கவனிக்க: இந்த மின்னூலைத் தனிப்பட்ட வாசிப்பு, உசாத்துணைத் தேவைகளுக்கு மட்டுமே பயன்படுத்தலாம். வேறு பயன்பாடுகளுக்கு ஆசிரியரின்/பதிப்புரிமையாளரின் அனுமதி பெறப்பட வேண்டும்.
இது கூகிள் எழுத்துணரியால் தானியக்கமாக உருவாக்கப்பட்ட கோப்பு. இந்த மின்னூல் மெய்ப்புப் பார்க்கப்படவில்லை.
இந்தப் படைப்பின் நூலகப் பக்கத்தினை பார்வையிட பின்வரும் இணைப்புக்குச் செல்லவும்: Water Resources of Ceylon

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WATER RESOURCES OF CEYLON
ITS UTILISATION
AND
DEVELOPMENT
BY
S. ARUMUGAM, B.Sc. (Lond.), B.Sc. (Eng.), F.I.C.E., M.I.w.E., Chief Engineer, Water Resources Board, Formerly Senior Deputy Director, Irrigation Department.
A WATER RESOURCES BOARD PUBLICATION Colombo, 1969

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FOREW ORD
Over thirty five years ago D. S. Senanayake wrote in his FOREWORD to R. L. Brohier's publication “ANCIENTIRRIGATION WORKS IN CEYLON’ that the “...greater part of the contribution to a knowledge of our past has been made by officers employed in the administration and technical branches of our ့်ဖြိုးငုံ Service. We owe indeed a deep debt of gratitude to these officers...’
I feel very much the same today as I peruse Mr. S. Arumugam's compilation on Water Resources Development in Ceylon, she has included in it ample information to stimulate the interest of visitors to the magnificent irrigation works of Ceylon. While delving into our glorious past, the present has not been minimised nor the future overlooked.
At present there is no one volume, official or otherwise, providing information on our Water Resources Developmnet Works, where they are or what they are like; this work amply satisfies that long felt need.
Mr. Arumugam has spent many years and definitely many hours of his leisure during his long career in the Irrigation Department in collecting and arranging the information contained in this monumental book.
This is a work of love and will be an example to the future generations of public servants.
C. P. DE SILVA
Ministry of Land, irrigation & Power, Colombo 1, 17th May, 1969.

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PREFA CE
Ceylon is blessed with ample rainfall: nevertheless, her people had to toil, through the ages, to conserve and utilise this precious natural resource. Though water is available in plenty over the year, it is by no means an easy task to be in a position to effect supply just where it is wanted and when it is wanted.
After assessing the water resources with which the country is served annually, an attempt is made in this compilation, to su/vey the story of conservation and utilisation of water resources in Céylon from the very early days of history.
A description follows, in chapter 3 of about 400 of the more important water resource development works in the River Basins of Ceylon. At the end is also shown proposed data of some of the works likely to be taken up in the immediate future.
Acknowledgement is made of the assistance rendered by Mr. A. Rajadurai with photographs of the works.
Intimation of any changes in the parameters of the works discribed would be appreciated.
S. ARUMUGAM
Water Resources Board, Colombo, June 1969.
BBLOGRAPHY
Reports of the Central and Provincial Irrigation Boards. Administration Reports of the Director of Irrigation. Journals of the Royal Asiatic Society. Concise History of Ceylon, University of Ceylon Press Board. History of Ceylon, University of Ceylon Press Board. Ancient Irrigation Works, R. L. Brohier. Irrigation Department Documents.

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C O N T E N T S
FOREWORD Preface
Chapter 1 Water Resources of Ceylon
Section -Resources
l.
General
Rainfall
River Basins of Ceylon Stream flow measurements Ground Water
Section II–Utilisation
6. 7. 8. 9. 10.
Domestic water supply Agricultural Development Industrial needs Hydro Power Water Shed Management
Chapter 2 Developing Water Resources
Work of the ancient Kings Achievements of Parakrama Bahu Development by the Dutch Enthusiasm of the British Governors Efforts of the Central Irrigation Board Development by the Irrigation DepartmentDevelopment by the Irrigation Department-II Independence and Development
Chapter 3 Development Works
Major River Basins 8 8 u e s Data of Development in the major river basins of Ceylon
Page
8
10
11 14
16 19 20 2
23
24 26 27
34 36

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Chapter 4
Projects Under Consideration
The Mahaweli Scheme (1) Diversion Anicut at Polgola (2) Moragahakanda Reservoir (3) Victoria Reservoir (4) Randenigala Reservoir Malwattu Oya Reservoir Scheme Samanalawewa Scheme Kelani Ganga Basin Scheme Deduru Oya Reservoir
399 399
401 402 404 405 406 407

CHAPTER 1
WATER RESOURCES OF CEYLON
SECTION -RESOURCES
1. General
Ceylon is a tropical island with a land mass of 25,332 Square miles (16 million acres or 6 million hectares), situated in the Indian Ocean, Latitude between 6 and 10° North and Longitude 80° to 81° East.
1.12. The island is subject to two monsoons; the South-Wes
monsoon prevailing from about April to September and the NorthEast monsoon from October to March. On the basis of distribution of rainfall, the island is divided into two distinct areas-the Wet and the Dry Zones. The Wet Zone comprises of the south-west area, covering about a quarter of the Island, extending southwards from Chilaw and terminating with Kandy and Nuwara Eliya in the east. The area of the Wet Zone is about 4 million acres.
The Wet Zone, with its two rainy seasons and an annual average rainfall of 95 inches, is well developed with economic crops-tea, rubber, coconut etc. The present economy of the country is largely dependent on development of the Wet Zone. -
1.13. The rest of the Island consists of its Dry Zone. The Dry Zone comprising of over 12 million acres, has only one rainy season, from about October to March, and the average annual precipitation is about 57 inches. The Dry Zone areas are arid and dry and well suited for irrigated agriculture.
2. Rainfall
1.21. The only source of water in Ceylon is direct rainfall; the amount of rainfall varies from place to place. The Island is served with a network of rain gauge stations, some of which have been in function for over hundred years. The more important stations are equipped with automatic recorders. Today there are over 600 rain gauge stations established all over the Island.
1.22. Rainfall, in the dry and wet zonal areas, during the twelve months of the year is depicted by the averages, shown below:- -

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Average Monthly Rainfall in Inches
Dry Zone Wet Zone All Island
January 7.5 4.2 5.9 February 2.7 2.6 2.7 March 3.3 5.7 4.5 April 4.0 8.8 6.4 May 2.9 1.7 7.3 June 0.9 9.3 5. July 1. 7.8 4.5 August 1.8 5.8 3.8 September 2.7 7.7 5.2 October 7.7 14. 0.9 November 2.0 1.5 1.8 December 10.6 6.1 8.4
Total 57.2 95.3 76.3
T.
Annual average rainfall at a few representative stations are shown below, as illustrated:-
Annual Rainfall at Selected Stations
Dry Zone Wet Zone Anuradhapura 56.9 Colombo 94.3 Kandy 79.6 JafÎina 52.3 Nanuoya 101.2 limbantota 42.3 Ratnapura 153.1
Mannar 38.1 Watawala 214.9
Annual Precipitation
1.23. Quantitatively the mean annual precipitation in the Dry Zone is about 57 million acre feet and 32 million acre feet in the Wet Zone totalling to 89 million acre feet as mean annual precipitation over the entire lsland.
3. River Basins of Ceylon
... Th basic requirement for any water resources development is the collection of comprehensive data. Knowledge of not only the water available for use, but also its conservation and distribution from se son to season, etc. For this purpose the Island his to be considered in small units, provincially or districtwise or what is mire natural, by river basins. A river basin is a natiral unit and lends itself ideally for water resources studies concerning rainfill, stream flow water use, drainage etc.
1.32. The territry of Ceylon can be divided into 103 component natural river basis ind another 94 small coastal basins. The 94 low lying coastal busins are small and have problems of their own; they do not make an elective contribution to the water resources of the Island. Several of cven the 103 river basins are not appreciably large.
2

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4>^). ତଠି \@そャゾー に代_しVい、陈^ ^ 心瓣@)) YYY)、y __ ~ ^ ~^|-• 的%고유/* @いい〜f~,^t @AQて~^ \,^+,^! @ ://! ;--,’~^,^~A
•@^r /„^7/!、 *-くQ/ / /!{ 戴/炽回/@4/ja ~^/இ/@) ;ミ引 {
P Arnca om.

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MAll AWELI GANGA CEY LON'S LARGEST RIVER
 

4. Stream Flow Measurements
1.41. Run off from the rivers of Ceylon varies very widely from stream to stream due to variations in rainfall, type of soil, its slope and other factors. For purposes of assessing the yield from river basins, stream gauging stations have been established to measure the flow of most of the more important rivers of Ceylon. There are nearly ninety stream gauging stations established in different localities, of which about thirty are equipped with current metering equipment. In most cases, the sites selected as flow gauging stations are potential impounding reservoir sites, with the result that there is no representative all Island coverage of stream flows in Ceylon. The ideal would be at least three gauging stations in each stream.
1.42. However, for purposes of assessment of total run-off in various streams of the Island, rates of flow have been synthesised? in the ungauged streams. In the tables that follow are shown the RUNOFF, so prepared, in the streams of the Dry Zone and the Wet Zone respectively.
1.43. The streams in the dry zone have poor run off varying between 10% to 50% of the precipitation; in about ten of them the percentage run off does not exceed 20%. The annual run off from the streams in the dry zone amounts to 20.7 million acre
feet.
But on the other hand, as would be expected there is more flow in the wet zone streams; the annual run off from the streams in the wet zone amounts to 20.9 million acre feet.
The total run off from all the streams in Ceylon thus amounts to 41.6 million acre feet.
RUN OFF FROM DRY ZONE BASINSl
BASIN RUN OFF in 1000 Ac. ft.
No. Name ܕ Area in Maha Yala Annual
Sq. Mis. Total 1-16. In the wet zone- --- mramm unus -- 17. Kachigala 86 73 27 100 18. Walawe Ganga 954 1,126 658 1,784
19. Karagan Oya : 22.5 1 9 20 20. Malala Oya 156 105 26 3 21. Embilikala Oya 23 15 4 19 22. Kirindi Oya 455 438 99 537 23. Bambawe Ara 31 21 5 26
Irrigation Department - S. Bocks. «w 2 Hydrometeorology of Ceylon, Part I. Rainfall and Run off. Messrs Hunting Survey Corporation Ltd. Toronto, Canada.

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RUN OFF in 1000 Ac. ft.
BASIN Area in Maha Yala Annual No Name Sq. Mls. Total
24. Mahasiliwa Oya 5 3 O 3 25. Butawa Oya 5 1 3 14 26. Menik Ganga 497 437 87 524 27. Katupila Aru 33.5 30 6 36 28. Kuranda Ara 5 43 9 52 29. Namadagas Ara 42 35 8 43 30. Karambe Ara 8 26 7 33 31. Kumbukkan Oya 476 516 70 586 32. Bagura Oya 36 44 55 33. Girikula Oya 6 3 3 6 34. Helawa Ara 20 4 4 8 35. Willa Oya 189 179 13 192 36. Heda Oya 236 273 29 302 37. Karanda Oya 65 187 9 196 38. Simena Ara 20 25 2. 27 39. Tamdiadi Ara 8.5 2 2 14 40. Kangikadichi Ara 22 25 2 27 41. Rufus Kulam 3.5 2 2 14 42. Pannel Oya 72 13 3 116 43. Ambalam Oya 45 68 2 70 44. Gall Oya 700 13,23 95 1,418 45. Andella Oya 204 310 14 324 46. Thumpankeni 3.5 3 O . 3 47. Namakada Aru 4.5 6 O 6 48. Mandipattu Aru 39 62 2 64 49. Pattanthe Dephue Aru 39 62. 2 64 50. Vett Aru O 20 2 51. Unnichchai 35 45 8 153 52. Mundeni Aru 500 578 3. 609 53. Miyangola Ela 88 95 6 101 54. Maduru Oya 602 1,062 7 1,133 55. Pulliyanpota 20.5 24 3 27 56. Kirimechi Odai 30 69 3 72 57. Bodigoda Aru 64 39 5 144 58. Mandan Aru 5 3 3 16 59. Makarachchi Aru 14.5 36 3 39 60. Mahaweli 4,034 2,836 1,470 4,306 61. Kantalai 174 214 7 221 62. Palampotta Aru 27 44 2 46 63. Panna Oya 56 87 3 90 64. Pankulam 47 26 7 223 65. Kunchikumban Aru 80 69 2 7 66. Palakutti Aru 8 8 O 8 67. Yan Oya 594 611 25 636 68. Mee Oya 35 35 36

RUN OFF in 1000 Ac. ft.
BASIN Area in Maha Yala Annual No. Name Sq. Mls. Total
69. Ma Oya 400 372 12 384 70. Churian Aru 29 29 30 71. Chavar Aru 2 12 O 12 72. Palladi Aru - 24 25 26 73. Munidel Aru 73 89 1 90 74. Kodalikallu Arth 29 41 1 42 75. Per Aru 146 81 4. 185 76. Pali Aru 33 43 1 44 77. Maruthapilly Aru 16 23 ... O 23 78. Thoravil Aru 35 38 39 79. Piramenthal Aru 32 40 1 41 80. Nethali Aru 47 50 51 8l. Kanakarayan Aru 350 325 12 337 82. Kalawalappu Aru 22 34 O 34 83. Akkarayan Aru 75 106 1 107 84. Mandekal Aru 116 120 1. 121 85. Pallararayan Kadu 62 51 0 51 86. Pali Aru 176 160 3 163 87. Chappi Aru 26 18 O 18 88. Parangi Aru - 32.5 260 6 266 89. Nay Aru 219 141 4 45 90. Aruvi Aru 1,268 962 42 1,004 91. Kal Aru 82 92 2 94 92. Moderagoma Aru 364 243 9 252 93. Kala Oya 1,083 795 64 859 94. Moongil Aru 17 11 O 95. Mi Oya 592 109 12 121 96. Madurankuli Aru 28 5 2 7 97. Kalagamuwa Oya 59 12 98. Rathambala Oya 84 94 10 104 99. Deduru Oya : 1,022 968 254 1,222 100-103-In the wet zone- - - ---
Total: Dry Zone 18,158 17,350 3,311 20,661

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RUN OFF FROM WET ZONE BASNS
RUN OFF in 1000 Ac. ft.
BASIN Area in Maha Yala Annual No. Name Sq. Mls. Total l. Kelani Ganga 885 2,372 3,435 5,807 2. Bolgoda 146 326 343 669 3. Kalu Ganga 1,050 2,801 3,493 6,294 4. Bentara 243 663 764. 1427 5. Madu Ganga 23 63 74 37 6. Madampe Lake 35 95 1 10 205 7. Telwatte Ganga 20 53 67 120 8. Ratgama Lake 4 12 23 9. Gin Ganga 360 734 816 1,550 10. Koggala Lake 25 63 74 137 11. Polwatte Ganga 91 125 130 255 12. Nilwala Ganga 375 625 585 1,210 13. Sinimodara Oya 15 24 22 46 l4. Kirama Oya 87 100 68 168 15. Rekawa Oya - 29.5 32 23 55 16. Urubokka Oya 136 143 63 206 00. Karambala Oya 230 205 87 292 101. Ratmal Oya 84 83 60 143 102. Maha Oya 590 795 775 1,570 103. Attanagalu Oya 284 300 38 618 Total: Wet Zone 4,712.5 9,613 11,319 20,932 Note: −
The above figures do not include (1) Area of Jaffna Peninsula including Vada
marachchi Lagoon 393.0 Sq. Mis. (2) Residual Area comprising largely Coastal
zones intervening between adjacent -
Basins 2,068.5 Sq. Mls.
1.44. The Average annual precipitation amounts to 89 million acre feet as indicated in para 1.23. A quantity of 41.6 million acre feet has been assessed as flowing in the streams as run off and the position may be shown as:-
PRECIPITATION AND STREAM FLOW (In million Acre Feet)
Dry Zone Wet Zone Total
Average Annual Precipitation 57 32 89 Run off - 20.7 20.9 41.6 Stream flow (37.5%) (65%) (47%) Balance 36.3 11.1 47.4
(62.5%) (35%) (53%)

5. Ground Water
1.51. Ground water is not an independent natural resource of a country. It is really a composite portion of the water resource, but available at a certain phase of the process of the water cycle movement. Undoubtedly it would entirely depend on the amount of surface flow that percolates into the subsoil, which is dependant on the nature of the subsoil.
An inventory of the ground water resources of the Island based on river basins has not been made, as no systematic exploration has been carried out.
1.52. Appraisal of ground water occurrences in Ceylon has been limited until recently to generalised statements indicating the possibilities of finding underground water in the five divisions the Island has been divided into:-
The Central Highland Zone. The Dry Lowland Zone. The Limestone regions of the North. The Coastal Zone.
The Jaffna Peninsula.
1.53. The Central Highland Zone of Ceylon consists o the wet region, enjoying very good precipitation, and rises up to 8000 feet in elevation. The igneous rocks of the area do not contain water, though some may often be found in the fissures and in the overburden. The amount is not copious.
1.54. The Dry Lowland Zone with less rainfall, has the same basic rock structure, but with different soil conditions. As in the above, ground water may be expected in the fissures. Where however the bed rock is irregular with depression, alluvial deposits in these depressions retain percolation, and can be recovered as ground water, before it finds its way to the sea.
1.55. A belt of Limestone Region extends along the western coast, northwards from Puttalam. In many places the limestone is covered over by red alluvial soil called ''Terra Rosa, often as much as twenty feet in depth.
Water occurs trapped in the solution cavities and in canal systems along joints and fractures. These caverns are expected to yield large quantities sufficient for irrigation purposes, etc. However, in view of the close proximity to the sea, the threat of sea infiltration is always there. -
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1.56. Fresh water is found in the sand dunes and permeable formations all along the Coastal Zone. The amount of water depends on rainfall and the nature of the locality. As this fresh water is more or less floating on the infiltrated sea water any attempt of heavy or deep draw off will bring up the sea water. Such sources may therefore satisfactorily serve the individual settlements in the locality.
1.57. The limestone belt along the western coast is best developed in the Jaffna Peninsula which is entirely composed of it. The surface of the area is generally flat rising to thirty two feet into the interior near Tellipalai. Soil cover is thin, about three feet generally, extending to about ten to twenty at a few places.
The fresh water trapped in the solution caverns which is found floating on sea water, forming a line is drawn out heavily for irrigation supply to garden crops, mainly chillies, onions, tobacco, etc.
The rate of depletion of the ground water has been alarming and recently fears have been expressed of several wells turning brackish with the exhaustion of fresh water storage and ingress of sea water.
With the intention of carrying out a hydrological investigation of the Peninsula, an organisation has been set up in March 1965, for the systematic observation of water levels and testing of sample water regularly in selected wells of the region.
Over four hundred wells, known as ''Observation Wells, have been selected, situated representatively all over the region of the Jaffna Peninsula. The water levels of the water in these observation wells are regularly measured and observations tabulated. Samples of water found at the bottom of these wells are collected and analysed for the presence of chloride ions, hardness as calcium carbonate and total solids present. The work is proceeding, but an interim report has been released.
SECTION I.-UTILIZATION
6. Domestic Water Supply
1.61. The quantity of water used for domestic consumption is relatively small compared to other consuming demands such as irrigation supply. Nevertheless this demand counts top-most in priority due to the nature of its service. Hence it receives priority in any water resource consideration.
The responsibility to effect domestic water supply to the public, generally rests with the civic institution of the locality. The Municipalities, Town Councils, Village Committees and the other Institutions of the Local Government secure financial assistance from the Central Government for the purpose and the service is executed by the Division of Drainage, Water Supply and Local Government Works.
8

1.62. The city of Colombo, with a population of over five lakhs, is served by the reservoirs across the tributaries of the Kelani Ganga. This is further augmented by pumping direct from the parent Ganga at Ambatalan and the system delivers over 40 million gallons per day including supply to towns south of Colombo as well. The Municipality of Kandy obtains about five million gallons daily from the Mahaweli Ganga and Negombo nearly 3 million gallons from Maha Oya. Besides these, there are about fifty other supply undertakings, These obtain their supply from batteries of shallow wells; their yield is usually inadequate for satisfactory issue. Further details appear in para 2.82.
1.63. It has been stated that 20% of the population in Ceylon is today receiving pipe-borne domestic water supply; if we apportion to each a maximum of 50 gallons per day (which of course is very excessive in the case of rural areas), the total amount of water used does not exceed 500 ac. ft. per day.
But in spite of the small quantity, the difficulty is to effect this supply at the place and at the time it is required.
7. AGRICULTURAL DEVELOPMENT
(a) Water for Irrigation supply ܖ 1.71. In Ceylon the use of irrigation supply has been mainly
confined to rice production. The following table indicates approximate water requirements for paddy production.
CONSUMPTION OF IRRIGATION WATER FOR RCE CULTIVATION
Requirements for the growth and maturity of a five month variety of rice plant:-
Maha Season Crop Yala Season Crop
Ас. ft. Ac. ft.
October () 0.50 April 0.75 November 0.75 May 1.75 December 0.50 June 1.50 January 1.00 July 1.25 February 0.75 August 0.75 March () 0.50
4.00 6.00
To mature an acre of rice crop about 4 acre feet of water is necessary, if it is cultivated during the wet months; 6 acre feet would be the requirement during the dry weather period. This is
*Administration Report of the Director of Water Supply and Drainage,
1965.
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usually termed the 'duty' of water supplied for irrigation. The quantity of water used would vary with the cultivation system adopted and the period of maturity of the particular variety of paddy.
1.72. With the need for more diversified agricultural enterprise, irrigated supply is now provided to more and more subsidiary food crops. Food crops, other than rice, that are now receiving consideration for irrigated water supply, include chillies, red onions,
Bombay onions, potatoes, pulses of several kinds and food grains such as Maize.
As a result of experiments, it has been found that the water requirements (duty) of some of these crops are as follows:-
Water Requirements of Subsidiary Crops'
Chillies 3 to 4 acre feet Red Onions 1. ίο , , و و Bombay Onions 1. tO 99 وو و و Small Grains 23 to , , ,
8. Industrial Needs
1.8. Industrial undertakings require water: (1) as aid to production (2) for cooling systems. In both cases some of the water would usually be discharged as effluent-often contaminated. The effluent is allowed to re-join the sources of supply only when purified and offensive acids, alkalies and poisonous chemicals, e.g., cyanides are neutralized and also factory residual waste is removed by pre-settlement tanks.
in planning, water resource supply for industrial needs the governing criteria are (1) the steady supply of the quantity stipulated throughout the year--as the factory cannot obviously be shut down for water shortage, and (2) the usual demand for more, due to subsequent expansion of the industry.
in Ceylon the problem, however, is in its infancy, but will rapidly show up as the programmed industrial development of the country gets into full production. The flow in the Kelani Ganga river has to be shared by the following undertakings;
1. The National Textile Corporation. 2, The Steel Corporation. 3. The Petroleum Corporation. 4. The Tyre Corporation. 5. The Fertilizer Corporation. 6. Kclinitissa Power Station. - Their demands impose a heavy call on the Kelani flow during the dry weather days.
There are other industrial concerns which draw off from other sources but there is no such heavy demand.
*Implementation Programme, 1962-Dept. of National Planning. O

9. Hydro Power
1.91. The only source of indigenous energy in Ceylon is hydroelectric power. The central hilly areas of Ceylon experience heavy precipitation, due to which stream flows descend rapidly to the lower regions; there are several water falls and over 50 of them have been listed.
The potential for hydro-electric development in the Island has never been systematically investigated. There is no inventory of all possible sites where such development is feasible.
1.92. The Economic Commission for Asia and the Far East in an early report mentions a potential of 1,000 megawatts of Hydro Power in Ceylon. When the Mission from the International Bank for Reconstruction and Development visited Ceylon they were shown a list of 13 stations where hydro-power development was feasible. This list, prepared in 1949, however assesses total potential at 500 megawatts.
The central highlands of Ceylon, where there is a concentration of high mountainous peaks with large rainfall and surrounded by a lower second plain, is basically suited for development of water power. But due to vagaries of rainfall, attempts at regular power production is impossible without impounding storage reservoirs; but the steep gradients of the mountainous streams necessitate high and therefore costly dams. Steep stream beds limit the storage capacity of the impounding reservoirs. So that hydro-power development becomes practical only where there are wide and long basins.
1.93. Mr. H. P. Pfeifer, a consulting engineer from the U. N. and Power Adviser to the Government of Ceylon, listed 30 possible hydro-electric power project sites in the Island in his report, over 5 years ago. He assessed the hydro-electric power that can be developed economically in Ceylon to be about 1,400 megawatts, and concluded that his computations show that the annual hydrel energy potentiah of Ceylon to be over 6000 million units of energy.
The more important sites selected by him were in the Kelani, Walawe and Mahaweli Ganga basins.
1.94. Since then several studies have been made and reports prepared by experts, summaries of which are indicated below:-
(a) Kelani Ganga Basin
(1) Kehelgamuwa Tributary, fully utilised (2) Maskeliya Tributary, works in hand; (3) In the middle reaches of Kelani Ganga, the following possibilities have been suggested by a U. S. S. R. Team in 1961. Nawatta Parusella Reservoir 36 M. W. 230 M. k. w. h. Yogama ss 15 s 130 sy Holumbuwa 穷多 12.5 , 16 sy * “The Economic Development of Ceylon, I.B.R.D. Mission, 1952.
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(b) Walawe Ganga Basin
(1) Samanala Wewa Reservoir.
Reports prepared (1966) by Engineering Consultants Inc., show
that 120 M. W. Plant can be installed, expecting 398 m. kilowatt hours of energy.
(2) Uda Walawe Dam has an installed plant of 6 M.W.
(c) Mahaweli Ganga
(1) The U. S. O. M. Team (1958-60) envisaged the following in a trans basin diversion project.
Nugawela Reservoir 120 M.W. 540 million Units Engery,
Cost Rs. 354 m. Diversion at Primose Hill Rs.. 434 m.
Ukuwela Plant 45 MW 333 m. Units Energy Cost Rs. 41 m. Diggala Plant 45 MW 333 m 99 , , , RS. 41 m. Lenadora Plant 33 MW 275 m. 99 ., ,, Rs. 34.2 m. Canal Units 17 MW 85 m. 9s , , Rs.. 42 m. (2) The UNSF (FAO) Team engaged (1966-68) on studies for the development of the Mahaweli Basin have the following:-
MAHAWELI GANGA HYDRO-POWER POTENTIAL 1. Mahaweli Ganga Cascade
No. Unit Installed Firm Energy
M. W. 106K. W. H. 1. Rozella a - 2.6 7.4 2. Trafalgar - 9.5 34.2 3. Carolina w a a II e 12.5 42.9 4. Koladeniya RP "O O. • 6.0 22.8 5. Ulapane A . . . . 21.0 59.6 6. aloluwa a w 17.3 60.4 7. Polgolla 8 0 38.8 183.0 8. Victoria Falls (1410-M. S. L.) 20.0 469.0 9. Randenigala (750-M. S. L.) ... 750 282.0 10. Rantanabe (495-M. S. L) 42.8 177.9 Total oo: 342.5 339.2
2. Kotmale Oya Cascade No. Unit Installed Firm Energy M. W. 106 K. W. H. 1. Agra a gy 5.1 20.0 2. Tillicoultry s a 1.4 40.7 3. Talawakcle a 40.0 132.0 4. Yoxford a 43.5 138.8 5. Kotmale s 105.0 447.6 6. Palmerston 8 a 2.2 5.6 Total ... ... 207.2 784.7
12

No.
N
O.
No.
i
3. Amban Ganga Cascade
Unit Installed Firm Energy M. W. 106 K. W. H. Kiula • p 22.3 98.9 Makeli Wewa s a 15.9 68.2 Kumbaloluwewa a a 40.0 15.2 Bowatenne No. 1 . . . . P s's 3.7 19.0 Bowatenne No. 2 wo e * * 40.0 1520 Moragahakande e ao o 40.0 1490 Total 0 0 O y a 1619 638.3
4. Uma Oya Cascade Unit O 8 O ... Installed Firm Energy M. W. 106 K. W. H. Bomurella 6.5 27.5 Wellimada 0.9 3.6 Puhulpola 7.3 22.3 Ettampitiya 22.1 70.4 Upper Uma Oya 25.5 95.5 Dematapelessa 2.5 85.5 Lower Uma Oya 30.0 13.3 Madulu Oya 6.9 26.2 Needan Kanda 5.9 24.3 Total 126.6 468.6
5. Badulu Oya and Loggal Oya Cascade Unit Installed Firm Energy M. W. 106 K.W.H. Rookatenna . . . 2.0 6.1 Upper Yelverton 1.8 5.5 Andeniya - - - . . . 14. 35.2 Kalawelpota a 6.1 14.6 Taldena 14.5 47.6 Pallewela 10.0 34.5 Total 0 to 48.5 143.5
6. Other Tributaries of Mahaweli Ganga Unit Name of Oya Installed Firm Energy M. W. 106 K. W. H. Naranpanawa Hulu Ganga 8.6 27.6 Tumpe Maha Oya 8.1 27.9. Heen Ganga Heen Ganga ... 7.1 25.5 Ratna. Ela Hasalaka Oya 12.4 38.9 Total 36.2 119.9
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Summary
No. River Installed Firm Energy
M. W. 106 K. W. H. 1. Mahaweli Ganga Cascade 4 342.5 1339.2 2. Kotmale Oya Cascade O 207.2 784.7 3. Amban Ganga Cascade B. A 16.9 638.3 4. Uma Oya Cascade ... s so 126.6 468.6 5. Badulu Oya & Loggal Oya Cascade 48.5 143.5 6. Other tributaries as a On 8 36.2 119.9
Total Potential e 922.9 3494.2
(d) Malwattu Oya Reservoir
This reservoir when constructed would have a plant of installed capacity 0.8 M. W.
(e) Kalu Ganga Basin
An assessment made in 1957 envisages the generation of 480 . million units of energy, with plant capacity 120 M. W. at a cost of Rs. 395 million, at various sites in the basin.
(f) The Gin Ganga and the Nilwala Ganga Basins are among
other possible sources.
The hydro-electric installations in commission in 1968 total only 110 megawatts; another 75 megawatts would be in commission by 1969. But the potential of the Island is 1,400 megawatts. The quest, therefore, is the securement of the balance 1.215 megawatts.
10. WATERSHED MANAGEMENT
l. 10. Il For the optimum utilisation of water resources, the country's watersheds have to be well managed. Proper management, by the prevention of indiscriminate clearing near stream-bed areas and the beds of streams and the cultivation and growth of permanent plantation, where such clearing has already taken place, forms the basis of water shed management. Such conservation is vital for thc cultivation of rice, the production of food, and forms the very cssence for existence of life in the hill country villages.
The watershed areas of streams and rivers are being indiscriminately cleared, depriving them of the natural vegetation and cover, which detain and hold up water flow and tend to make the streams perennial. As this process is continuing unchecked, there would eventually be no detention in any water course: the streams will run down the hill slopes fast as torrents, be exhausted and dry up immediately afterwards; there would then be a long dry season. All this, for want of detentive effect in the watershed area. The wanton destruction of natural water retentive capacity of the terrain is becoming widely prevalent, and what is more, is rapidly spreading.
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If a curb is not imposed at this juncture, the streams and elas in the hill country areas would all deplete and dry up; they would no longer be the perennial sources of domestic or irrigation water supply to the villagers, in the valleys. The situation concerns their very existence.
There is in Ceylon no specific legislation dealing with measures concerning the conservation of watershed areas that feed the water courses and streams. The Soil Conservation Act deals with measures necessary for the Conservation of the Soil-and that too only in ''erodible’’ areas, including re-afforestation of streams etc., it does not provide for measures specifically necessary for the Conservation of Water. A draft Act to be cited ''Water Shed Management Act has been prepared for enactment.
It provides for the declaration of any watershed area as ''conserved watershed and would normally be directed to concern fringe areas along streams and water courses. These are not always necessarily Crown reservations. It would apply to beds of streams too, whether private or Crown. Regulations could be framed, insisting that in areas so declared, only approved form of agricultural plantation, that is plantation of a permanent nature which do not require the frequent or annual stripping of under cover and natural vegetation, could be adopted. Maintenance of the Village Tank is fundamental to sustain life in the low country village. Just the same way, conservation of the Watershed is vital for the hill country village. The Village Tank is an artificial reservoir storing rain water for use during non-rainy months: the watershed is natural retention (sub soil) reservoir of rain for water flow in streams, making them perennial. The attention that is given to the former cannot be denied to the latter; both are vital to the nation.
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CHAPTER 2
DEVELOPNG THE WATER RESOURCES
1. THE WORK OF THE ANCIENT KINGS
2.11 The conservation of water and its distribution for rice cultivation became the foremost and solemn duty of the Kings of ancient Ceylon and those Monarchs who discharged this obligation were held in high esteem and veneration by the people.
The ancient chronicles of Ceylon viz. Mahawamsa, Culavamsa etc. make mention of tanks existing in Anuradhapura even during the pre Christian pariod of the 6th and the 5th centuries B. C.
The Tissa Wewa, a City Tank of Anuradhapura, is attributed to King Devanampiya Tissa (250-210 B.C.).
Irrigation practice by the diversion of small streams and from small privately owned tanks is recorded to have been developed by the first century B. C.
Soon afterwards, development progressed from privately owned minor tanks to works of major utility, where not one individual but a whole group or community was benefited.
2.12 King Vasabha (65-109 A. C.) is recorded to have been responsible for the construction of eleven tanks and twelve canals, thus earning the name endowed on him by posterity, as the 'First of the great Tank Building Kings. Six of these tanks have been identified, including:
Vaha Vapi (Panikkan Kulam of Puttalam-A'pura Road) Mahanikkhavatti (Manakattiya Eastern Minor Road 12th Mile) Aggivaddhamavaha (Hirivadunna near Habarane). Mayanti and Mayetti tanks (may be the Willachchiya tanks). and of the canals only the Alisara (Elahera) canal is now known, to perpetuate his name.
2.13 Development progressed actively thereafter and larger tanks, in fact the celebrated sixteen large reservoirs of King Maha Sena (276-303 A. C.), the Great Tank builder, are then recorded. Eight of the sixteen tanks constructed by him are identified to-day:-
Mahagama Vapi Challur Vapi (Huruluwewa) Khanu Vapi (Mahakandarawa Tank) Kokavata. Vapi Mahamani Vapi (Maminiya near Maradankadawela) Dhammaramma Vapi Kumbalaka Vapi (Kimbulvana, now known as Niramulla)
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Vahana Vapi Rattamalakandka Vapi (Padaviya Tank) Velangavitthi Vapi Tissavadhamanaka Vapi (Kaudulla Tank) Mahagalaka Vapi Cira Vapi Mahadaragalaka Vapi (Mahagalkadawela) Kalapasana Vapi (Karampankulam)
and foremost of them all Manihira Vapi (MINNERIYA TANK), where he is worshipped today at a shrine on the tank bund, a fitting tribute to the legacy left by him.
He is also said to have been responsible for the construction of the great Pabbatahata canal identified now as the present Minipe Canal-the dam across the Mahaweli (Manimekhala Dam) was however built later by Aggabodhi I.
2.14 King Dhatusena (459-477 A. C. became immortal with his foremost irrigation work-the Kala Vapi (Kala Wewa) built across the Kala Oya and the Jaya Ganga (Kala Wewa-Yoda Ela) the 52 mile long canal to convey the Kala Wewa waters to the city of Anuradhapura. Besides the twin tanks Kala Wewa and Balalu Wewa, he is recorded to have constructed 18 tanks of which 4 were major works, including:
Mahadatta (Madatugama at 51st M. S. Dambulla-Anuradhapura Road) Maha Eli (Mealiya Waya on 12th mile Ibbagamuwa-Polpitigama Road). 2.15. A King who distinguished himself in literary scholarship and in development work alike was Moggallana II (535-555 A. C.). During his reign were constructed, Pattapasana Vapi (Nachchaduwa Tank) along with a five mile feeder channel (now a natural stream) from there to Nuwara Wewa, in Anuradhapura. To him is. also ಖ್ಖted restoration or enlarging of Dhana Vapi (Padaviya Tank).
To Aggabodhi I (575-608 A. C.) a model king, who ruled for 34 years, is attributed the development of -
The Manimekahala Dam-The anicut across the Mahaweli Ganga at Minipe, along with improvements to about 17 miles of the Minipe Ela Scheme, built earlier. The Minneriya Kantalai Yode Ela, conveying water from Minneriya tank to Kantalai. Kurunda Vapi, now known as Thannimurippu Tank of Mullaitivu.
Aggabodhi II (608-618 A. C.) continued the development works commenced by his uncle Aggabodhi I and constructed the Gangatata Vapi (Kantalai Tank), into which the 54 mile Minneriya Kantalai Yode Ela terminated. To him is also attributed the construction of Giritata Vapi (Giritale Tank) fed by a branch of the Elahera canal.
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2.16 Thus by the seventh century A. C., the following were among the larger achievements accomplished by the ancients in developing the water resources of Sri Lanka:-
Major Reservoirs (those known now)
Minneriya Mahakandarawa Kaudulla Tank Hurulu wewa Padaviya Kalawewa Nachchaduwa Thannimurippu Tank Kantalai Tank Giritale Tank Thusa Vapi
River Diversion Works and Canals
Elahera canal Kalawewa Yode Ela and Tissawewa Feeder channel to and Nuwarawewa Minipe anicut and 17 miles of Minipe Yode Ela Minneriya Kantalai Yode Ela Hattota Amuna and channel
Although not many new works were done during the three centuries that followed, the monarchs nevertheless repaired, strengthened, enlarged and restored the works already accomplished by the earlier kings.
2.17 The Kala Wewa spill is reported to have been strengthened by King Mahinda II (777-797), when a feeder channel was also constructed from there to Tintinigamaka Vapi (now called Usgala Siyambalagamuwa Tank).
The Minipe Ela Scheme was extended to a total length of 47 miles, during the reign of King Sena II (853-887), when an augmentation scheme was also provided to Mahakandarawa Tank by a dam near Maradankadawela.
2.18 Names of other kings of that period who interested themselves in irrigation matters and in the preservation of work include Udaya II (887-898), and Sena III (938-946). But the most strenuous effort at restoration and consolidation of irrigation works was by Vijayabahu (1055-1110). He is reported to have put into function once again the Elahera Canal; among the tanks which received his attentions were Minneriya, Kaudulla, Kantalai, Nachchaduwa and Mahakandarawa tanks.
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2. THE ACHIEVEMENTS OF PARAKRAMA BAHU THE GREAT
2.21 Parakrama Bahu I (1153-1186), assumed charge of his own principality of 'Dakkinadesa, contained in the area between Kalu Ganga and Kala Oya. Conservation and Development was his key note to the path of plenty. He demonstrated his own dictum that water that comes from rain must be made useful to man.
2.22 The Deduru Oya (Jajjara Nadi), the river of his principality of Dakkinadesa, was first harnessed by damming at three major works sites. The Kotthabaddha anicut with the present Sengal Oya near Chilaw, the Sukaranjhara (Ridi Bendi Ela anicut) and the uppermost dam, Doradattika, below the present anicut site at the junction of the two streams Hakwatunu Oya and Kimbulvana Oya. Along with this fifty three tanks were restored or improved in the area, chief of which was Panduvasnuvara, near Hettipola which was given the title of the first ''Sea of Parakrama.'
With the military conquest over his rivals and the subjugation of their territories, his own development plan spread out, eventually to cover the whole island of Ceylon. No irrigation work built before his time escaped from being put into working condition to ensure productivity everywhere.
2.23 It is recorded that Parakrama Bahu I was responsible for the construction, restoration and enlargement of:-
163 ... Major Tanks 2,376 ... Minor Tanks
165 ... Anicuts 3,910 ... Channels from tanks and anicuts.
a most stupenduous achievement
The Mahawamsa narrates the ambitions of this great tank builder as follows:-
'In my kingdom are many paddy fields cultivated by means of rain-water, but few indeed are those which are cultivated by means of perennial streams and great tanks. By rocks, and by many thick forests, by great marshes is the land covered, In such a country let not even a small quantity of water obtained by rain, go to the sea, without benefiting man. " . Paddy fields should be formed in every place, excluding those only that produce gems, gold, and other precious things.'' The Sea of Parakrama (the Parakrama Samudra) was the masterpiece of his many ambitious projects and stands today to commemorate his achievements.
2.24 Foremost of all the works initiated during the period is the present Parakrama Samudra Scheme; it consisted of the Angame- ,
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dila anicut across the Kara Ganga (Amban Ganga) and the conveyance of the diverted flow by an inlet channel (Akasa Ganga) to Parakrama Samudra which earlier were three individual tanks: Topa Wewa, Dambutulu wewa and Eramaduwewa; now these are merged (on restoration) to form the present Parakrama Samudra at Polonnaurwa.
2.25 Thus by the 12th century, water-conservation had reached its zenith in Ceylon with a record which was the greatest achievement in history,
During the three centuries that followed, no new development was promoted: even the completed works went into decay: developmental activity was probably confined to the maintenance in working order of the works in the neighbourhood of the capital cities of Dambadeniya, Yapahuva, Kurunegala and Gampola,
3. DEVELOPMENT BY THE DUTCH
2.31 The position did not change with the arrival of the Portuguese (1505-1656), whose interest in agricultural enterprise was confined to cinnamon only.
2.32 The Dutch were in Ceylon for about 150 years from 1656 A. C. Unlike their predecessors, attention was paid by them for the agricultural development of Ceylon. Grants of lands were freely made for this purpose and a regulation published in 1666 prohibited owners of rice fields from leaving them uncultivated. Another order in 1744 announced seizure of such uncultivated lands to be given to other “more diligent cultivators.' The Dutch found it good economy to encourage agriculture in the low country and aided this with costly undertakings, by the construction and restoration of engineering works.
2.33 The most striking contributions made by the Dutch in Ceylon are the well known Dutch canals. These were excavated primarily for economical water transport but also aided agricultural development by draining the neighbouring areas and rendering them suitable for cultivation.
The Negombo and Kalutara canals facilitated the drainage of Muthurajawela and the Kotte area. The Maha Modera canal in Galle was expected to relieve flooding in the neighbouring low basin. Similarly the Nupa and Talagahagoda canals in the Matara area.
2.34 Paddy cultivation in the Colombo and Galle areas received much attention by this as 'a great part of the crops were being lost either having too great or too small a quantity of water. A long earthen embankment, over seven miles in extent, was erected along the northern bank of the Kelani Ganga, and which is in use today, known as the Kelani North Flood Protection Bund -to prevent the periodic inundation of the paddy fields in the
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low basins around Kelaniya. The lands situated adjoining the Nilwala Ganga were drained and irrigation facilities provided by suitable dams, etc. The Kirama Oya was regraded and facilities provided for diversion of water to paddy fields.
* By far the foremost of the Dutch water conservation work is the Urubokke Dam, completed in 1787 by Lt. Foenander to improve cultivation of 8000 acres.
2.36 Other works include the Irakkamam dam and the Amparai tank repair works by Bunnand, and improvement works to Kantalai Tank by Engineer Fornabur. Progress in development appears to have been very vigorous in the latter half of the 18th century during the administration of Vandegraaff.
4. ENTHUSIASM OF THE BRITISH GOVERNORS
2.4 The British took command of the maritime areas of Ceylon by 1798 and the entire Island in 1815.
Progress in the development of water resources in the Island, during the 150 years of the British occupation of Ceylon, divides into three distinct periods:-
Development, initiated by the enthusiasm of the Governors of the time. • . Efforts of the Central Irrigation Board and the Provincial Boards. Development by the Irrigation Department.
2.41 There had been an attempt with a proposal to restore Giant's Tank by Sir Thomas Maitland in 1806 which the Dutch too investigated for restoration but nothing was done; generally not much interest was taken on irrigation matters. However, following the pattern set up at Urubokke by the Dutch, the Kirama Dam was however constructed in 1825, across a tributary of the Nilwala Ganga. y
With the removal of the Rajakariya system in 1832 the communal machinery by means of which tanks had been kept in good repair from the very ancient days, terminated, without a substitute in its place. So the maintenance and up keep of communal water conservation works was not the responsibility of any individual or group and the works just wasted into general decay.
Even the Kirama and Urubokke Dams breached in 1837.
2.42 To Sir Emerson Tennent, Colonial Secretary in 1847, belongs the credit of reviving interest in irrigation development by legislative authority, with measures for the gradual restoration of irrigation schemes. This idea, later in 1855, culminated in the hands of Sir Henry Ward, Governor of Ceylon (1855-1860). The 'Irrigation Ordinance of 1856' described as the 'Ordinance to facilitate the revival and enforcement of ancient customs regarding the Irrigation and Cultivation of Paddy lands, was enacted.
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The Act was to be in force for 5 years from 1. 1, 1857 and was limited in the scope of application to those areas in Ceylon where there were large tracts of paddy land dependent on a single source of irrigation.
Under the terms and conditions of the Ordinance, funds were obtained and Sir Henry Ward was able to, during his term, to put back into working condition the works of the Dutch, viz: Irakkamam work in Batticaloa and the Urubokke dam and Kirama dam in the south.
The Irrigation Ordinance of 1861 was a renewal of the first, but the revised Irrigation Ordinance of 1867 embodied the required modifications with a wider scope covering repair of village tanks and minor works as well. •
2.43. Sir Hercules Robinson, Governor (1865-1872) was able to embark on developmental activity on a large scale.
The reward of his enthusiasm enabled commencement of reconstruction and restoration, and in several cases even completion during his term. Among the schemes were:-
S. P. N. W. P. Kekandura Tank Deduru Oya scheme Hali Ela Tank Kospotu Oya scheme Tissamaharama Tank Tinipitiwewa Udukiriwela Wennoruwewa
E. P. Uva Periyakulam Horaborawewa Rugam Tank Buttala Ela Pulukanavakulam Kudawewa
and about 25 others, with a record expenditure (considered, then, as astounding) of Rs. 1,050,000.
2.44 His successor in office, Governor Sir William Gregory (1872-1877) was equally keen and the tempo of development was nearly doubled and several works of restoration were taken up including:-
S. P. E. P. Urapola anicut Allai scheme
Sakamam A Chandiyantalawa
Kantalai Tank
N. C. P. N. W. P. Basawak kulama Maha Uswewa
Madawachchiya Tank Galgamuwa Tank. Yoda Ela from Kalawewa Elahera canal
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and a large number of village tanks, the restoration of whict was the special interest of Sir William Gregory whose requiremen was “that at least one hundred village tanks be properly repaired
each year.'
2.45 Sir Arthur Gordon (1883-1890) once again revitalised irrigation development and kindled enthusiasm which had worn out with the departure of Sir William Gregory and several works were taken up for restoration during his regime.
The restoration of Kalawewa was taken up, costing Rs. 405,095. The restoration of Kalawewa Yode Ela (Jaya Ganga of Old) was then (1889) undertaken, costing Rs. 304,484. Along with these the City Tanks of Anuradhapura, Nuwarawewa, Tissawewa and Basawakkulama were also restored. -
5. EFFORTS OF THE CENTRAL RRIGATION BOARD
2.51 In 1887 an Ordinance was passed creating a Central Irrigation Board, with the Governor as President, for the general management and promotion of irrigation. Provincial Boards were also set up with the respective Government Agents, of the area as Presidents who were entrusted with the execution of all works in their areas. No special staff was however provided and the works executed by the staff of the Public Works Department. Restoration Works taken up, included:-
Hambegamuwa Tank in Uva Bodi Ela in C. P. (3 miles) Kitulbokke Scheme in Sabaragamuwa Province. Uggalkaltota Scheme in Sabaragamuwa Province. Kanagarayankulam in N. P. Lahugala Tank in E. P. Maha Nanneriya in N. W. P. 2.52 A review of the progress achieved in the restoration and construction of irrigation development works, indicate the following position by the end of the Year 1889.
Large Small Anicuts Channels Length
Tanks Tanks of restored restored Channeł
W. P. -- -- -- C. P. 1. 28 104 168 197 N. P. 5 35 1 - S. P. 13 26 96 105 303 E. P. 20 8 1 5 7ן N. W. P.. 7 981 3 3 13 N. C. P. 6 1,148 -- 14 61 Uva P. 10 27 28 26 00 Sab... P. -- 2 2 5 Total 59 2,250 245 326 700
miles, of Channels
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2.53 During the next five years construction and restoration work was commenced and in may cases completed at:-
Kumbukkan Anicut (Uva) Bowatenne Ela (C. P.) Bodi Ela w (C. P.) Had breached seriously
and taken up again. Irakkamam, Sagamam and Thum
pankerni (in E. P.) Rugam (which had breached in 1881). Badulu Ela (Uva) è Hingura Ara Tank - (S.P.) Deduru Oya Works (N. W. P.) Yoda Wewa (S.P.) Madukande, Cheddikulam,
and Periyakulam (in N. P.)
work at Giant's Tank was slow and later received a set back due to an epidemic of Cholera (1898).
2.54. In 1896, it was decided to vest entirely in the Director of Public Works the responsibility for the execution of irrigation works, relieving the Government Agents of this task. For this purpose a special Irrigation Assistant (Henry W. Parker) and a number of Junior Engineers were added to strengthen the P. W. D.)
A new Irrigation Manual was published on the 18th of March 1899, which helped to define responsibility for the maintenance of irrigation works.
6. DEVELOPMENT BY THE IRRIGATION DEPARTMENT-I
2.6 1900-1907-In order to expedite the execution of irrigation works, a separate Irrigation Department, as distinct from the Public Works Department, was formed on the 15th of May 1900, with H. T. S. Ward as first Director of Irrigation, H. W. Parker, Irrigation Assistant, and seven Irrigation Engineers.
All surveys, designs and construction of new works restoration and maintenance of large schemes were the responsibility of the new Department. The Government Agents (the Provincial Board being abolished) were concerned about the upkeep of minor works carried out by the villagers themselves.
2.61 In 1904, Henry W. Parker, Irrigation Assistant, who had by the time become a most valuable officer and whose reports on the ancicnt irrigation schemes are even now works of authority, retired from Government Service. The Director of Irrigation (H. T. Ward) writes:-"“He (H. W. Parker) served in all the malarial districts of the Island and knew more about the ancient irrigation works than all the rest of the inhabitants of the island put together. He spoke Tamil, and Sinhalese fluently and was a Pali Scholar.
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He designed Deduru Oya Works, Giant Tank restoration, the Karachchi Scheme and reported on numerous irrigation schemes all over the island............... ''. Today he is more well known and remembered than even any Director of Irrigation of old.
The new Department, embarked on several new large construction works, besides repairing and improving several smaller works and was able to show in 1907 the accomplishment of the following:
Kirindi Oya Scheme Walawe Scheme Giant's Tank Kala Wewa Deduru Oya Works . Vakaneri Sagamam-Vammiyadi Pattipolaru Scheme Nachchaduwa Tank.
2.62 An important event was the arrival in Ceylon of W. L. Strange, loaned by the Indian Government. His report on ''Irrigation in Ceylon'' was published in 1909. Work on Iranamadu Tank which was a new construction work was proceeding steadily and the Dri Aru Tank was done in 1908, as a preliminary work to -cater for the labour camp and the water supply etc. Amparai, Kondavaddavan & Vellathipathi Tanks in E. P. were completed and Illakantai tank, Trincomalee executed in one year (1912). An estimate for Rs. 374,700/- was approved in the same year for the restoration of Tabbowa Tank,
2.63 The existing Irrigation Ordinance was revised and the new 'Irrigation Ordinance No. 45 of 1917 was enacted and framed in accordance with the recommendations of Strange's Report of 1908. Irrigation rates were now made variable with development and no longer remained fixed.
2.64. In 1917 the technical staff were relieved of the administration of cultivation rules, which from now on became a responsibility of the Government Agents.
2.65. Iranaimadu Tank, commenced in July 1902, was completed in 1921; it filled and was spilling in November same year. The investigation of the flood problem in Colombo area from Ja-Ela to Kalutara was commenced in 1920. The proposals were accepted and the work on the Colombo South Flood Scheme commenced on 18th October 1923.
2.66. Due to intense rainfall Illakantai Tank breached in 1923.
Lemasooriyagama anicut was completely overturned in 1923, and Madawachchiya Tank in N. C. P. also breached.
2.67. During the four years from 1924 construction work was -carried on at good pace; foremost among the works carried out were the Colombo South Flood Protection Works, the Colombo
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North Flood Protection Works, which was commenced in 1924. and completed in time to save Colombo from the 1926 floods; and the Left Bank Irrigation Scheme under the Liyangatota anicut, Walawe Scheme. The restoration work of Tabbowa, which was recommenced in 1921, was completed in 1925 and the tank filled for the first time and was spilling on 8. 12. 1925.
2.68 By 1930, the Irrigation Department was responsible for the maintenance of the following water conservation works:-
TABLE X
l64 Major Irrigation Works, Colombo South and North.
Flood Scheme Works 82 Miles of Tank Bund 563 Miles of Channels
95 Miles of Roads.
7. DEVELOPMENT BY THE IRRIGATION DEPARTMENT
2.71. A new irrigation policy was announced by D. S. Senanayake, Minister of Agriculture & Lands, in 1932, whereby improvements, to village irrigation works also became the work of the Department. Ceylonising the higher engineering grades was also initiated.
2.72. The Department also launched out on carrying out of Minor Flood Protection Works, preventing Kelani Ganga Flood Waters inundating low lying adjoining basins up to a predetermined flood height called Minor Flood Level or Level of Flood Protection.
Rufus Kulam Works which commenced in 1930 was completed in 1932. Akathimurippu channel construction was completed in 1934. Walawe L. B. Scheme was nearing completion. The Kelani North Bund (Dutch Work) was improved.
2.73. An event of great importance was also the utilisation of heavy mechanical equipm nt, for the first time, in the execution of development works. A Rustan Bucyrus Excavator excavating channels and a Caterpillar Tractor assisting breach closure work at the Eramadu Gap, P. S. Scheme are events of 1936-37.
Construction work was commenced at several large major works:-
Topa Wewa (P. S. S. 1st Stage) Ridi Bendi Ela
Mini pe lEla (1st Stage) Bathmcdila Ela (1st Stage) Colombo South Drainage-Wellawatte canal Attanagalla Oya Scheme
Elahea Scheme.
2.74. Mahaweli Ganga was harnessed for the first time in recent years by the restoration of the Minipe Anicut during FebruaryMarch, 1939.
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2.75. In spite of dislocation of normal activity in the Island due to war conditions (the Air raid on Colombo was on 5th April 1942,) work was carried on, on the following projects:-
Parakrama Samudra Scheme Minneriya—Stage III Elahera-Stage II Bathimedila—Stage II Kottukachchiya Nilwala Ganga-M. F. P. S. Gin Ganga-M. F. P. S.
Parakrama Samudra Scheme filled for the first time on Feb. 22nd, 1944.
2.76. A new land policy was initiated. It was considered insufficient to construct tanks and the irrigation channel systems only, but in addition to the land being opened up, asswedumisation should be done before the colonists were settled. -
A new land development unit embarked on clearing land and erection of colonists cottages at: Minipe, Kahagama, Elahera & Parakrama Samudra Schemes.
Irrigation development was pushed forward with great vigour iduring this period specially for the food production drive and work was commenced in July 1945 on the restoration of Devahuwa Tank and Murapola Scheme in October 1945. The ancient Elahera canal was mended with incredible speed by enthusiastic officers and the Ambanganga waters harnessed for immediate cultivation needs.
8. INDEPENDENCE AND DEVELOPMENT
Development Directed by Ministers of State
2.8. With the dawn of political freedom economic progress was the chief pre-occupation of Independent Ceylon. To this goal each Cabinet Minister directed his activities. The development of water resources for agricultural production (irrigation) was the responsi
bility of the Ministry of Agriculture and Lands. Water Conservation works for domestic water supply and for hydro-electric generation were subjects of the Minister for Communications & Works; due to subsequent re-allocations of functions of Ministers, the development of water resources now concern the Minister of Lands, Irrigation & Power-for the development of irrigation and hydropower, the Minister of Agriculture and Food-for the up-keep of minor irrigation works and the Minister of Local Government-for domestic water supply.
2.81. With 1947 came the long awaited day of Independence. By that time:-
''Gal Oya has become a household word. It is symbolic of the New Lanka. May it obtain fulfilment speedily and herald the progress of our march towards self-sufficiency.'
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With these words the Rt. Hon. D. S. Senanayake, Prime Minister, unveiled the commemoration pillar erected at Inginiyagala on which was inscribed in Sinhalese, Tamil and English the simple dedication:
“This commemorates the inauguration of the Gal Oya Irrigation and Power Project. Opened by the Hon. Mr. D. S. Senanayake, Prime Minister of Lanka on August 28, 1949.
The Gal Oya Scheme was envisaged as a multi-purpose project, and preliminary works were done in 1948; active construction commenced in 1949. The dam and headworks were completed later and the Senanayake Samudra commenced issuing water for the first time on the 10th of December 1951.
2.82. The first six year programme was drawn up for irrigation development during the years 1947/48 to 1952/53, as part of the post war programme of work. In this the completion of the following Schemes were envisaged:-
Six-Year Programme-1947/48 to 1952/53
Giritale - - - 623 Parakrama Samudra ... 14,050 Elahera ... 4,504 Raja Ela −a-
Minneriya - - - ... 3,216 Kahagama Ext. ... 1417 Nuwarawewa Ext. 506 Bathmedila ... a l, 12 Minipe Ext. ... . . . . 952 Ridi Bendi Ela ... 1,695 Dewahuwa .., 2,337 Gall Oya v ... 41,000 Kantalai Ext. ... 2,000 Allai Ext. ... 7,000 Walawe Res. ... 1,000 Hurulu wewa . . . 500
Total M « ... 81,912 Acres of new lands
Progress of work was channelled to the construction and the completion of these works by Mr. Dudley Senanayake, Minister for Agriculture and Lands. Minipe Stage I and the Minneriya Augmentation Schemes were completed in 1949-50; Huruluwewa, Kandalama, Kantalai, Giritale and Mahakadawewa Projects were completed by 1953. -
2.83. With the completion of the first six year programme towards the end of 1953, there were:-
1 13 Miles of tank bunds
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54 Miles of flood bunds 1267 Miles of channels
363 Miles of roads 634 Buildings
completed and maintained for effecting irrigation water supply to:
271,433 Acres under Major Irrigation Works and 412,350 Acres under Minor Irrigation Works.
The next programme commenced in 1954 by (Mr.) P. Bulankulame Disawe the then Minister for Agriculture and Lands included:
Vavunikulam Padaviya Maha Wilachchiya Mi Oya and Badulu Oya schemes.
A vigorous programme of development was commenced by Mr. -C. P. de Silva who assumed charge of the Ministry since 1956 with the following works:-
Giritale Extension Gal Amuna Hakwatunu Oya Usgala Siyambalagamuwa Mora Wewa Muthu Iyan Kaddu Kulam Kaudulla Tank Mahakanadarawa Tank and Chandrika Wewa.
Foods of 1957
2.84. But a most tragic event overtook all development activity in 1957. Torrential rains, unprecedented in living memory, fell. on the 24th to 26th December 1957, causing such catastrophic 'devastations as never experienced before-rainfall recorded at Habarana was 16.48 ins. on the 24th, 18.76 ins. on the 25th and 13.59 ins. on the 26th. Serious damages were caused to 35 major irrigation works and 1300 village tanks. Among the major tanks that breached were:-
Kala Wewa Hurulu Wewa Nachchaduwa Giant's Tank Akkarayankulam Pavatkulam Iratperiyakulam Unichchai Tank and, Rugam Tank.
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Repairing all these ravages and putting back into commission, many of these giants of old necessarily slowed the momentum that would otherwise have been accomplished in new developmental construction works.
2.85. Soon afterwards however the pace of development was. renewed with ever greater vigour and several large conservation projects, storage reservoirs and river diversions were embarked upon, among which are the Minipe Ela Extension Scheme, Muttu Aiyan Kaddu Klulam, Vavunikulam Reservoir, Akkarayan Kulam, Allai Extension Scheme, Morawewa Extension Scheme, Hakwatunu Oya Reservoir Scheme, Maha Kandarawa Scheme, Padaviya Extension Scheme, Rajangana Wewa, Angamuwewa Scheme, Kaudulla Scheme etc.
Construction work was commenced in 1963 on the Uda Walawe Dam across the Walawe Ganga, for the development of over 60,000 acres by the conservation and storage of over 200,000 acre feet of Water.
Work on the storage reservoir at Muruthawela and at Nagadeepa was commenced in 1966.
In the subject of Water Resources Conservation and utilization Ceylon is just now in the midst of an epoch making era when a most stupendous project, bigger than any, ever thought of, is being evolved.
The Mahaweli Ganga, our longest and largest river is to be harnessed, whereby six million acre feet of water is to be conserved to aid the development of nine lakhs acres. The work would cost about Rs. 6,000 million and would be spread over a period of twenty years.
The architect of this project is the Minister for Lands, Irrigation & Power.--Mr. C. P. de Silva. ܖ
Ground Water Exploitation
2.86 in 1964, two deep wells were drilled in the limestone regions, North of Puttalam
The first was at Kondachchi, about fifteen miles south of Mannar, where the surface was about 100 ft. above mean sea level. Red soil extended to 28 ft. depth and gravel up to 35 ft. depth. Thereafter sand mixed with limestone was encountered. Good limestone was first encountered at 90 ft. depth, and when broken through, water rose, on release, by 17 ft. Drilling was continued to over three hundred feet depth.
Yield tests were made later; these showed that even when pumping was done at 235 gallons per minute, the draw down as shown in a neighbouring drill hole did not exceed 3 feet, even after six hours of pumping. Plenty of supply is presumably available in the sub
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terranean regions of this locality. The quality of the water however was below standard.
The second well drilled at Vannathivillu about 12 miles north of Puttalam gave slightly different results.
Here again the surface was about hundred feet in elevation. The water bearing limestone was encountered and broken at a depth of 140 feet. When broken, water rose by seventy feet from the ground. Drilling was continued to a depth of 300 feet. With the pump lowered to a depth of about a hundred feet and working at its maximum speed of 235 gallons perminute, the draw-down was 30 ft. by which time pumping was stopped.
Since then several wells have been drilled and are being exploited for the lift irrigation scheme of the Vannathivillu region.
2.87. Hydro Power Generation
In the absence of coal fields, hydro power has always been looked upon as the only form of natural power available in Ceylon.
Electricity supply system from thermal stations was initiated in Ceylon in 1895, by private enterprise to serve the city of Colombo. The Pettah power station erected in 1898 served for several years. ့်y had electricity supply from 1901 and Nuwara Eliya from 1912 etc.
It was in 1910 that F.D. Rylands, Government Electrical Engineer,
first presented a report on the possibilities of harnessing the flow in the upper reaches of the Kelani Ganga for the generation of electrical power. Later in 1918, D. J. Wimalasurendra who was engaged in its investigation, formulated proposals for the AberdeenLaksapana Project, which was subsequently modified to the present Laksapana Hydro Electric Scheme. Work was started on the project in 1924 but was suspended in 1927; the economic depression and the outbreak of the World War delayed recommencement till 1940, when after a few set-backs, work was finally completed in 1950. The capacity of the project is 25 M.W. and a total cost was Rs. 55 Million. -
In 1954, the next stage of the work was commenced with the erection of a dam at Castlereagh. Castlereagh Reservoir storage augments the storage at Norton and aids generation of a further 25 M. W. at the Laksapana Station.
With the completion of a tunnel from Castlereagh to Norton a further capacity of 50 M. W. was brought into commission in 1964 at the Norton Wimalasurendra Power Station, which is the second hydro electric station to utilise the flows from the 65 sq. miles catchment of Kehelgamuwa Oya, tributary of the Kelani Ganga.
In the meanwhile at Inginiyagala, with the completion of the dam across Gal Oya in 1952 hydro electric generation was commenced;
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Later with the installation of the balance two units in 1963 the complete four units have a generating capacity of 10 M.W.
The waters stored in the Uda Walawe Reservoir, harnessing the flow of the Walawe Ganga, is designed to generate 6 M.W. hydrel power at power stations erected at the sluices of the reservoir.
The Maskeliya Oya, tributary of the Kelani Ganga is to be fully harnessed for hydrel power generation. The first stage of the project now under construction expected to be completed in 1969, comprises of impounding the flow in the oya with a dam at Mousakelle and installing a generating station at Polpitiya of 75 M.W. capacity.
Domestic Water Supply
2.88. Development of water resources for domestic water supply was confined to the city of Colombo at the commencement.
Supply to Colombo is obtained by the erection of a storage reservoir at Labugama, impounding the flow in Walk Oya, a small tributary of the Kelani Ganga. The work is 28 miles east of Colombo and was constructed in 1886 and is expected to yeild 12 million gallons per day.
To augment the above supply, the construction of another reservoir impounding the flow in Kalatuwawa Ela, an adjoining tributary of the Kelani Ganga, was commenced in 1949 and completed in 1960. The estimated yeild from this source is 20 million gallons per day.
Besides the above, a pumping station installed at Ambatalenpahala, about eight miles from Colombo, is also utilised to augment the supply to the city from the flow in Kelani Ganga.
2.89. Water supply schemes for other places in Ceylon were executed by the Public Works Department. In 1955 a proper program was prepared for the systematic execution of several supply schemes and in 1961 a separate Department of Water Supply and Drainage was created, under the Ministry of Local Government, for the execution of several schemes of pipe borne water supply.
All the nine Municipalities viz: Kandy, Galle, Jaffna, DehiwalaMt. Lavinia, Kurunegala, Negombo, Nuwara-Eliya, Badulla and Matale have water supply schemes, although some of them may not be adequate. Kandy with the recently completed pumping scheme from the Mahaweli Ganga near Peradeniya, is now adequately served; so is Negombo's with the supply from the Maha Oya.
Besides the above, over fifty Urban Council and Town Council areas are provided with pipe borne domestic water supply.
The supply to these schemes are generally obtained from the following kinds of sources:-
Well water from sand formations as found in Batticaloa,
and Mannar. Well waters from the limestone formation as at Jaffna.
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Well waters from the beds of streams as at Tangalle. River waters as from Mahaweli Ganga for Kandy, Kelani Ganga for Colombo (Part), Walawe Ganga for Hambantota, Maha Oya for Negombo. Water from Irrigation storage tanks as from Nuwara Wewa
for Anuradhapura. Surface drainage, from protected catchment stored in a
reservoir, as at Labugama for Colombo.
Due to limitations of the recuperative capacities of the sources of draw off, the supply schemes do not all of them provide the 50 gallons per head per day in Municipal areas, 30 g. d. in urban and 10 g. d. in rural areas. However, overall computations show that nearly 100 million gallons are supplied per day for domestic water supply.
Minor Irrigation Works
2.90. Nearly 400,000 acres of rice cultivation in Ceylon is supplied with water conserved in small irrigation works all over the Island; these minor Irrigation Works (or Village Irrigation Works) are small water conservation storage tanks or stream diversion anicuts looked after by the beneficiaries, under the care of Cultivation Committees, who are responsible for their maintenance and upkeep.
2.91. The land tenure system of the Island has been the subject of reform from time to time.
The Paddy Lands Act of 1958 was introduced in order to provide security of tenure to the tenant cultivator who otherwise was reluctant to improve the land or adopt cultural practices which would bring in higher yields. The new Act made tenancy a heritable right and also established a new institution called the Cultivation Committee. The Cultivation Committee was elected by farmers from among themselves. The new Act was enforced only in six Districts in 1958, but gradually others were included and by 1963, all the 22 Districts of the Island had been brought under the Act.
Over four thousand Cultivation Committees have since been set up and their duties include preparation and maintenance of registers of paddy lands, fixing of wage-rates of agricultural labour, adopting steps for the development and maintenance of irrigation works, efficient cultivation of paddy lands and the maintenance of their fertility.
The Department of Agrarian Services annually spends over four million rupees in effecting such repairs and improvements to Minor Irrigation works which the shareholders themselves are unable to perform. The work is generally done by the Cultivation Committees.
In the Agricultural Development Proposals of the Ministry of Agriculture and Food, for the years 1966/1970, the Department has financial programme for annual expenditure of about ten million rupees on minor irrigation works.
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CHAPTER 3
DEVELOPMENT WORKS
I. Major River Basins
3.11. The Island's area is divided into 103 component natural river basins.
Thirty six of these in number as shown in the list below have catchment areas of over 100 sq. miles and are usually termed Major (comparatively) River basins.
1. Kelani Ganga 19. Kantalai Basin and Per Aru 2. Kalu Ganga 20. Pankulam Aru 3. Bentota Ganga 21. Yan Oya 4. Gin Ganga 22. Ma Oya 5. Nilwala Ganga 23. Per Aru 6. Walawe Ganga 24. Kanakarayan Aru 7. Kirindi Oya 25. Mandekal Aru 8. Menik Ganga 26. Pali Aru 9. Kumbukkan Oya 27. Parangi Aru 10. Willa Oya 28. Nay Aru l l. Heda Oya 29. Aruvi Aru 12. Karanda Oya, Iremeti Aru 30. Modaragama Aru 13. Gall Oya 31. Kala Oya 14. Andella Oya, Navakkiri Aru 32. Mi Oya 15. Magalawatavan Aru 33. Deduru Oya 16. Mundeni Aru 34. Karambala Oya 17. Maduru Oya 35. Maha Oya 18. Mahaweli Ganga 36. Attanagalla Oya.
3.12. It may be pointed out that of these thirty-six basins, those with common characteristics can conveniently be collected into three groups:-
The South-West Monsoonal Basins; The North-East Monsoonal (Dry Zone) Basins; Basins that receive benefits from both the monsoons.
The South West Monsoonal Basins
3.13. Important rivers of this group are:-Kelani Ganga, Kalu Ganga, Bentota Ganga, Gin Ganga, Nilwala Ganga, Maha Oya and Attanagala Oya. Generally they receive copious precipitation from April to September and are wet even during the other months. Land use predominates with tea, rubber, coconut and some rice cultivation. The area is well populated. Most of the areas are
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already well developed. The need for irrigation is limited. Essential requirement and pressing demand in all these basins is flood prevention and effective internal land drainage, particularly in the lower reaches.
What is required therefore, at all these south west monsoonal river basins, is the erection of flood absorption reservoirs in the upper reaches, embodying hydro power generation wherever possible. As would be seen later, measures for the construction of these are at various stages of progress.
3.14. There are also low lying small basins all along the fringe of the seaboard of the Island. Of these, the basins in the south-west monsoonal area, which lie along the western coast from Negombo to Tangalla have distinct problems of their own, which may be listed as follows:-
1. Their drainage into the sea remains blocked by sand bar for
mation at the outfall, for about 10 months of the year.
2. Inundation of the area by minor floods is therefore inevitable
during this period.
3. During the post flood period sea water travels up the drainage 盟 and intrudes into the cultivable lands, rendering them Sac.
Works needed at these basins would therefore necessarily consist of
1. Measures, such as sea groyne walls to keep the sand bars open. 2. Salt water entry prevention structures. 3. Wherever possible, creation of inland lakes for fish and prawn
culture and inland fishery harbours.
The North East Monsoonal or the Dry Zone Basins
There are twenty six basins in this Group.
3.15. These form by and large, the most extensive part of the Island. Unlike the wet zone, the area is dry and arid that no crops can be grown without irrigation; a hazardous crop cultivation is practised during the rainy months of October to December, but the success of that is subject to the vagaries of seasonal rainfall. It is now realised that the future development and prosperity of the country lies in the planned development of the dry zone.
The two most important natural resources are land and water; but land use is not possible without irrigation and irrigation becomes possible mainly as a result of storage reservoirs. Priority then, for this zone, is for more and more irrigation storage reservoirs.
All the twenty six basins of this group have the common characteristic, there is land, there is water; the water resources have to be harnessed for irrigation supplies to convert the arid lands into arable productive lands.
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Several reservoirs have been constructed and ancient works restored in these basins, details of some of these are given, as each basin is dealt with and a few illustrations are also shown.
River Basins that receive benefits from both the Monsoons
3.16. There are two rivers which receive appreciable benefits from both the south-west and the north-east monsoons. These two bi-monsoonal rivers therefore have perennial flow conditions.
The Mahaweli Ganga is unique in that it is the only river that flows along the length (more or less) of Ceylon whereas, other rivers commencing from the central hills reach the sea as quickly as possible.
The second of these, the Walawe Ganga, has its source in the hills and flows in a southerly course.
The Deduru Oya, though strictly not a bi-monsoonal river, has its source in mid-country and flows down to the dry zone.
2-DATA OF DEVELOPMENT IN THE MAJOR REVER BASINS OF CEYLON
Having thus made an assessment of all our water resources, reviewed the water requirements for each of type of activity, and attempted a grouping of related river basins, the stage is set for the consideration of actual developments in each basin.
With this in view, each of the 103 river basins of Ceylon is now considered separately, in an anti clockwise order commencing from Kelani Ganga, giving details of major development works that have taken place in these with illustrations of some of them.
LIST OF RIVER BASNS
l. Kelani Ganga 17. Kachigala 2. Bolgoda 18. Walawe Ganga 3. Kalu Ganga 19. Karagan Oya 4. Bentara , 20. Malala Oya 5. Madu Ganga 21. Embilikala Oya 6. Madampe Lake 22. Kirindi Oya 7. Telwatte Ganga 23. Bambawe Ara 8. Ratgama Lake 24. Mahasiliwa Oya 9. Gin Ganga 25. Butawa Oya 10. Kegalla Lake 26. Menik Ganga 11. Polwatte Ganga 27. Katupila Aru 12. Nilwala Ganga 28. Kuranda Ara 13. Sinimodara Oya 29. Namadag s Ara 14. Kirama Oya 30. Karambe Ara 15. Rekawa Oya 31. Kumbukkan Oya 16. Urubokka Oya 32. Bagura Oya
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33. Girikula Oya 34. Helawa Ara 35. Willa Oya 36. Heda Oya 37. Karanda Oya 38. Simena Ara 39. Tamdia di Ara 40. Kangikadichi Ara 41. Rufus Kulam 42. Pannel Oya 43. Ambalam Oya 44. Gall Oya 45. Andella Oya 46. Thumpankeni 47. Namakada Aru 48. Mandipattu Aru
49. Pathanthoddathane Aru
50. Vett Aru 51. Unnichchai 52. Mundeni Aru 53. Miyangola Ela 54. Maduru Oya 55. Pulliyanpota 56. Kirimechi Odai 57. Bodigoda Aru 58. Mandan Aru 59. Makarchchi Aru 60. Mahaweli 61. Kantaliai 62. Palampotta Aru 63. Panna Oya 64. Pankulam
65. Kunchikumban Aru
66. Palakuttai Aru 67. Yan Oya 68. Mee Oya
. Ma Oya . Churian Aru . Chavar Aru . Palladi Aru . Nay Aru . Kodalikallu Aru . Per Aru . Pali Aru . Maruthapilly Aru . Thoravil Aru . Piramenthal Aru . Nethali Aru . Kanakarayan Aru . Kalawalappu Aru . Akkarayan Aru . Mandekal Aru . Pallarayan Kadu . Pali Aru . Chappi Aru . Parangi Aru . Nay Aru . Aruvi Aru . Kal Aru . Moderagoma Aru . Kala Oya . Moongil Aru . Mi Oya . Madurankuli Aru . Kalagamuwa Oya . Rathambala Oya . Deduru Oya . Karambalan Oya . Ratmal Oya . Maha Oya . Attanagalla Oya.
The numbering adopted above for each basin is identical with the numberings of basins in the published maps of 'Planned River
Basin Development of ''Irrigation and Power' of the Ministry.
This numbering is maintained in what follows in dealing with individual basins. Some of the smaller basins have however been
omitted.
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1. KELANI GANGA BASIN
Natural Conditions w−
The Kelani Ganga is one of the main rivers of Ceylon; it has its
source in the central hills near Adam's Peak and, flowing through
the south-western part of the Island, falls into the sea at Colombo.
It takes the sixth place in respect of its extent of water shed, viz., 885 sq. miles, but, nevertheless, with an annual average yield of 4.86 million acre feet, becomes second from the water resources aspect due to bounteous rainfall in the catchment. The basin is about 56 miles long from east to west and about 28 miles in width (north-south). -
Hydrology
Annual precipitation of rainfall in the Kelani Ganga basin varies from 225 inches in the hill country to 86.5 inches in the low-country flat plains.
The Kelani Ganga starts at the confluence of Kehelgamu Ganga and Maskeliya Oya; (from the mountain range of Kirigalpotha at an elevation of 7867 M. S. L.). In the same region other tributaries. such as We Oya, Gurugoda Oya, Sitawaka Ganga etc. join up bringing in an abundance of drainage. The characteristic feature of all ;မျိုး tributaries is their steep gradient, dropping about 200 ft. per ΠΠΕ,
Floods
As a result, prevalence of floods in the basin is a frequent feature. The heavy precipitation in the upper catchment causes the river to overflow its banks in the lower region. The flood plain is formed below the Glencorse Gorge which is 32 miles upstream of the sea outfall of the Kelani Ganga, the river bed level at the Gorge being 11 feet above M. S. L. Below Hanwella the flood plain becomes. much wider.
Land Use
The upper basin is planted with tea. Rubber predominates in mid-country occupying about 110,000 acres; Coconut 160,000 acres and rice cultivation in about 95,000 acres. Towns, villages, home gardens and some vegetable gardens, etc., form the balance 120,000 acres. Due to availability of good clay, manufacture of brick and tile, and pottery making is lucrative.
Power
The flow down the Ganga has been harnessed satisfactorily for hydro power.
The Kehelgamuwa tributary has been fully tapped with a 43,800 acre feet reservoir at Castlereagh and a small 730 acre feet reservoir at Norton Bridge. The first supplies water for hydro generation of the 50 M.W. installed plant at Norton and the second to another 50 M. W. plant at Laxapana.
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The Maskeliya Oya tributary is being dammed at Mousakelle to detain 88,000 acre feet to generate 75 M.W. of power at Polpitiya.
This forms Stage I of Maskeliya Scheme.
The second and third stages compose of the installations of 75 M. W. and 22.5 M. W. capacity plants for further use of water already stored at Mousakelle under Stage I.
Irrigation
In this basin of abundant rainfall, rice cultivation is carried out with the aid of village schemes utilising unregulated flow from small streams and with direct rainfall. There is no scope for any new venture as all lands are already developed. There will be no large scale use of Kelani Ganga water for extensive irrigation projects within the basin.
Domestic Water Supply
The flow down the river is used for domestic water supply of some villages and lower down, for augmenting supply to the City of Colombo. At present about 5 million gallons per day is being drawn off at Ambatalenpahala pumping station for this purpose; this quantity is to be increased to 75 million (300 acre-feet) in the future.
Water Supply for Industrial Use
Industrial projects are being mooted along the banks of the lower reaches of the Ganga, all of which would be requiring the flow in the river for their use. An indication of their probable requirements may be as follows:-
Acre Feet M.G.D. Per Day
Textile Corporation l 6 Steel Corporation 3. 14 Petroleum Corporation 20 80 Tyre Corporation 3. 14 Fertilizer Corporation 30 120 Grandpass Power Station 80 320
554 Colombo Water Supply 40 South Colombo Supply 64
104
The requirements would increase as productions are raised to maximum capacity of the installed industrial production plants.
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Reports on the Development of the Kelani Ganga Basin
The Kelani Ganga has been studied and reported on mainly from the point of view of the Flood Problem as it concerned the capital city of Colombo and the neighbouring areas.
In 1948, John Cotton, Consulting Engineer, U. S. A., prepared a report on the Control of the Kelani Ganga. He envisaged a storage reservoir in the upper reaches at Glencorse with a 75 M.W. hydro plant and the strengthening of existing embankments.
The International Engineering Co. Inc., San Francisco, U. S. A., made detail studies and suggested several alternative flood control schemes in 1948.
A mission from the International Bank for Reconstruction and Development prepared a scheme in 1952 for the re-settlement of lood victims to higher localities in preference to undertaking costly reservoir construction. -
A team of experts from the Technopromexports, U. S. S. R., in 1961, prepared a report on the “Kelani Ganga Basin Scheme, for flood control and utilisation of water potential of the basin with a view to flood protection development of power and irrigation.'
The feasibility report prepared by them envisages the construction of (1) two reservoirs across two upper tributaries; (2) Hydro power generation of 33 M.W.; (3) diversion canal system to irrigate 146,500 acres of new land in the adjoining basins; (4) embankment along the banks of the river in the lower reaches, costing in all about Rs. 920 million.
The following are some of the water resources development works in the basin, considered in the pages that follow:-
Mousakelle Reservoir Castlereagh Reservoir and Wimalasurendra Power House Norton Dam and Laksapana Power Station Labugama Reservoir
Kalatuwawa Reservoir
Kelani Ganga Water Supply Scheme to Towns South of
Colombo.
Kelani Ganga Minor Flood Protection Schemes Muthurajawela Scheme Colombo North Flood Protection Scheme Colombo South Flood Protection Shceme Colombo South Drainage Scheme.

1.1 MOUSAKELLE RESERVOIR
(and Polpitiya Power Station) Location:
Situated at Mousakelle on the Norton-Maskeliya Main P. W. D. Road.
Co-ordinates L/15(2.1 x 1.6)
Project:
To impound the flow in Maskeliya Oya, a tributary of the Kelani Ganga, for the development of Hydro power at three sites lower down the valley.
DATA Source of Supply: Catchment area 50 sq miles Dam: Concrete gravity structure.
Length of dam at crest 615 feet Maximum height 115 feet. Reservoir Full: •
Storage capacity 93,000 ac. ft. Area of water spread 1750 acres Operational status
Normal maximum water level 3830 M. S. L. Normal minimum water level 3758 M. S. L. Allowance for dead storage 8000 ac. ft. Spill:
Three radial gates each 35 ft. by 15 ft.
Polpitiya Diversion Dam: Object: w
Sited about 700 feet below the Laksapana power house, i.e. about 7 miles from Mousakelle reservoir, this dam diverts the flow in Maskeliya Oya (consisting now of flow in Maskeliya Oya and the diverted flow from Norton Dam discharged through Laksapana Power House) into the Polpitiya tunnel for power generation.
Dam:
Concrete gravity structure
Length (at crest) 430 feet Max. height 100 feet Free overflow section 55 feet Balance non-overflow Gated spillway
(3 openings) 115 feet Gates 24 feet high.
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Reservoir Full
Storage capacity 115 acre feet
Full supply water elevation 1233 M. S. L. Intake to tunnel: -
Invert level 1215 M. S. L.
Size: 15 x 13 feet Tunnel:
Length 23,000 feet (approx. 4 mils.) Surge Tank:
Diameter 21 feet
Power Plant at Polpitiya:
Two Francis turbines each driving a 37 MW generator, have a total capacity of 75 M.W. Annual output of electrical energy expected is 313 million units; This project which forms Maskeliya Hydro Electric Scheme Stage I is designated Samanela Power House.
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1.2 CASTLERFIGH DAM US VIEW
1.2 WIMALASURENDRA POWER STATION & SWITCH YARD

Page 30
W 鶯
Wዪ 黨
1.3 LAXAPANA CONTROL ROOM
 
 

1.2 CASTLEREAGH RESERVOR
(and Wimalasurendra Power House) Location:
Across Kehelgamu Oya, also known as Hambantota Oya in the upper reaches, about 4 miles above Norton Dam.
Co-ordinates: L/15 (3.1 x 3.9) Project:
Impounding the flow in Kehelgamu Oya, and conveying the storage through a tunnel for hydro power generation at the Wimalasurendra Power House at Norton. Constructed during 1956-58.
DATA
Source of Supply:
Kehelgamu Oya Catchment . 44.5 sq. miles. Average annual rainfall 137 inches. Concrete Gravity Dam:
Length at top level 711 feet. Max. height 155 feet. Reservoir Full:
Storage capacity 43,830 ac. ft. Head of water 65 feet. Area of water spread 910 acres. Operational status:
Elevation of full water level 3590 M. S. L. Elevation of minimum water level 3525 M. S. L. Spillway:
Length 470 feet. Sluice at 3525 M. S. L. Power Generation:
Tunnel: w
Length 4 Miles. Size: Horse Shoe shaped with side radius of
11 feet and crown radius of 3 ft. 6 ins. Conveyance 1000 cusecs. Level at inlet (sluice) 3525 M. S. L. Pipe Line:
Two pipe lines each 48 ins dia. at top end tapering down to 36
ins. dia. at the power house end.
Power House:
Water Wheels-Pelton wheels, single runner, horizontal double jet turbines. Each wheel consumes 125 cusecs at full load for
the continuous output of 12,500 K.W. generated at 11,000 Volts 3 phase 50 cycle with a capacity of 50 M.W. An annual output of 123 million units of electrical energy is expected to be generated costing about 3 cts. per unit. This project is usually referred to as Stage II B.
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13 NORTON RESERVOR
(and Laksapana Power House)
Location:
The Norton dam is sited across the Kehelgamuwa Oya-a tributary of the Kelani Ganga, where the Oya crosses the GinigathenaMaskeliya P. W. D. Main Road under the bridge known as the Kotelawala Bridge, near the 10 M. S. The site is about 100 miles from Colombo.
Co-ordinates: L/15 (0.0X 7.0) Project:
The reservoir, formed by the dam regulates the flow in the Oya for diversion of storage for power generation at Laksapana Power House and was completed in 1950.
DATA Source of Supply:
Drainage from the Kehelgamuwa Oya catchment 65 sq. miles in extent, partly direct and partly after detention (and power generation) in Castlereagh Reservoir, built higher up in the same basin.
Concrete Gravity Dam:
Length at top level 345 feet. Maximum height 94 feet. Size of inspection gallery 6 ft. 3 ins high and 3 ft. wide.
Reservoir full:
Storage capacity 744 ac. ft. Head of water 36 feet. Area of water spread 36 acres. Operational status:
Elevation of full water level 2844. M. S. L. Elevation of minimum water level . 2808 M. S. L. Active storage 315 ac. ft. Spillway:
Length 240 ft. Sluices:
Supply to tunnel conveyance. Power Generation:
Tunnel
Length: 8400 ft." Size: 8 ft. wide by 9' 3" high (horse shoe shaped) area 65 sq. ft.
44

Conveyance 500 cusecs Level at inlet (sluice) 2808.0 M. S. L. Level at outlet (surge chamber) 2796.5 M. S. L. Overall drop in level 11 ft. 6 inches.
Surge Chamber:
Height 71 ft.-6 ins.
Diameter 40ft, Level of floor 2766.5 M. S. L. Pipe Line:
Length 5000 ft. Gradient 1 in 3 Two 68 inch pipes each bifurcating into two 48 inch pipes at top end of pipeline; these are reduced to 36 inches at the bottom end which in turn bifurcates to, two of 28 inch pipes.
Laksapana Power House:
Maximum static head at the Power House is 1580 ft. Floor level is 1275 M. S. L. Water Wheels-Pelton type. Type: Single runner, two jet type running at 600 rp.m. Effective head on the wheel is 1474 ft. and each wheel consumes 83 cusecs at full load for the continuous output of 8,333 KW generated at 11,000 volts three phase fifty cycle. Total output 50,000 K.W.
When Stage I of this project was completed in 1950 the capacity was 25 M.W; with the completion of Stage IIA, which includes the Castlereagh Reservoir and necessary extensions to the Power House at Laksapana, the entire project at Laksapana has a capacity of 50 M.W. and is expected to generate annually 270 million units of electrical energy at a cost of about 2 cts per unit (Kilowatt hour)
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1.4 LABUGAMA RESERVOR
Location:
At Labugama, about 29 miles east of Colombo. Co-ordinates: L113 (3.6 X 2.2)
Project:
Storage reservoir impounding the flow of the Wak Oya for water
supply for domestic consumption in the City of Colombo. Construction completed in 1886. Improvements were effected
subsequently.
DATA
Catchment area-2500 Acres (3.9 sq. miles) Reservoir Full:
Storage capacity 1960 million gallons (7200 ac. ft). Depth of Water 73ft。 Area of water spread 205 acres
Elevation of full supply level 374 above Mean Sea Level Safe Yield 12 million gallons per day.
Service Reservoirs:
Two of 8 million gallon capacity each, at Elie House and at Maligakande.
As the consumption in Colombo is however about 21 million gallons a day the supply is augmented from Kalatuwawa Reservoir. The work is maintained by the Colombo Municipal Council.

1.5 KALATUWAWA RESERVOR
Location:
The Kalatuwawa Ela basin adjoins the Labugama Reservoir basin, and is situated about 24 miles east of Colombo. Co-ordinates: L/13 (4.4x2.8)
Project:
A storage reservoir impounding the flow in the Kala uwawa Ela for domestic water supply to residences in Colombo.
DATA
Catchment area of Basin, 3,320 acres (5.2 sq. mls.) Main Dan
Length 930ft。 . Concrete gravity section 710ft
Earthen embankment 220 ft. Height (Max). 72ft。
Reservoir Full
Storage capacity 3900 million gallons (14,400 ac. ft.)
Head of water 60 ft.
Elevation of F. S. L. 370 M. S. L.
Area of water spread 454 acres Spill
100 ft. long provided in the concrete section.
Water Treatment Plant
Designed to purify 20 million gallons per day. Estimated safe yield-20 million gallons per day.
The Kalatuwawa Reservoir with 33" is pipe line from Kalatuwawa to Dehiwala, 4.2 million gallon Reservoir at Dehiwala and 30" is pipe line from there to Wellawatte, augments the supply from Labugama to the City of Colombo. These works are in the charge of the Colombo Municipal Council.
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1.6 THE KELAN GANGA WATER SUPPLY SCHEME TO TOWNS SOUTH OF COLOMBO
Object
The flow in the Kelani Ganga is drawn off at Ambatale and supplied to Dehiwela, Mount Lavinia, Moratuwa, Kotte, Panadura and Kolonnawa.
Scheme
The project consists of river intake works and treatment plant at Ambatale near the 8th M. S. on the Colombo Hanwella Road, 40 miles of 1000 m.m. diameter pipe line to the service reservoirs at Dehiwela, Moratuwa and Panadura, and water towers at Delhiwela-Mt. Lavinia, Kotte and Kolonnawa. Necessary pumping stations, lift the supply to the water towers from the service reservoirs.
Progress
The project is at various stages of construction; at the commencement excess supply available at Kalatuwawa is being utilised for the project; but this scheme would eventually supply 26 million gallons, daily to the six areas mentioned above.
48

1.7 THE KELANI GANGA MINOR FLOOD PROTECTION SCHEMES IN THE LOWER REACHES OF THE RIVER
The several tributary basins of the Kelani Ganga in its lower reaches frequently fill up by reverse flow from the swelling Ganga due to heavy rainfall in the upper reaches of the hill country. To aid the agricultural development in these basin areas Minor Flood Protection Schemes had been evolved preventing the back water entry of Kelani Ganga.
2. The basin entrance is dammed by a bund in which is incorporated a masonry structure with either flap one-way gate (automatic) or screw down gate or/and plank bays for manual manipulation. The Ganga, however, enters the protected basin when the river rises over a certain level-the level of protection. The minor protection level by convention is worked out by actual observation to be the level at the site corresponding to the Flood Level of 5 ft. at the Nagalagam Street Gauge, Grandpass, Colombo. By these devices it is expected that the protected basins will not be inundated by the Kelani Ganga up to the point of the Minor Flood Level mark, viz., 5 ft. When the water reaches above that level it enters the basin through suitably provided spills and floods them and there is no longer any protection.
3. The introduction of the impediment, mainly gates, however large they may be in number would no doubt cause a certain amount of delay or time lag in draining out the basin's own drainage into the Ganga. Whereas flood water in the basin used to rise and fall freely with the water level in the Ganga when there was no Minor Flood Protection Works across it, now the basin drainage has to await the fall in the river flow before discharge through the sluices could occur. Thus, the most disputed aspect of Minor Flood Protection Projects is the retardation of post flood basin drainage.
A. MNOR FLOOD PROTECTION SCHEMES ON THE LEFT BANK OF KELANI GANGA
1. Ambatalenpahala Minor Food Protection Scheme (1930), a large basin just East of Colombo extending to about 5 miles with drainage outlets at Grandpass-two flood gate openings 6”×5', Sedawatte-10 flood gates 5'x4' and at Ambatale by the Main Road-4 flap gates 5'x4'.
2. Weliwita Minor Flood Protection Scheme (1930), situated near 8 Mile Post with two number 3’ diameter Armco gates.
3. Hewagamuwa Minor Flood Protection Scheme (1933), near
10 Mile Post has three of 18" diameter gates.
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Bomiriya Minor Flood Protection Scheme (1937) L/12 (4.2x 8.2) catchment area 25 sq. miles at Kaduwela, has eight number gates 5'x4'. Length of Structure 73'-6". Protection level 20.50. Extent benefited 3000 acres.
Ranala Minor Flood Protection Scheme (1934) L/12 (8.1 x 6.8) has three number 3’ diameter gates.
Henpita Minor Flood Protection Scheme (1940) L/12 (8.9X 6.3) has six number 5'x4' gates two of which are screw down type to admit floods; Catchment area 4 sq. miles; Protection level 28.6; area benefited 580 acres.
Kaluaggala-Berendi Gampala Minor Flood Protection Scheme (1960), the sluices are on the Kaluaggala/Labugama Road near bridges 1/6 and 1/9 and have rows of 4 diameter pipes.
Akkarawita Minor Food Protection Scheme (1960), has eight number flood gates 5'x4' these cover the basins that lie along the Colombo/Hanwella Road from Grandpass up to Kaluaggala.
B. Minor Flood Protection Scheme on the Right Bank of Kelani Ganga
1.
Talwatte Minor Flood Protection Scheme (1934), L17 (0.65X 0.55) near 7: Mile Post on the Kelaniya/Diyagamuwa Road has three number 3’ diameter gates. Protection level 16.50. Extent benefited 300 acres.
Pattiwila Minor Flood Protection Scheme (1933), near the 9th Mile Post has three number 18" diameter gates and two planked bays of 5 ft.
Yabaruwela Minor Flood Protection Scheme (1933), L/7 (4.9 x 0.2) near the 11th Mile Post close to Diyagama junction has three number 3" diameter gates. Catchment area sq. mile. Level of protection 2000. Extent benefited 200 acres.
Pahuru Oya (1934), L/7 (6.1 X 0.3) Malwana Minor Flood Protection Scheme has 6 flood gates 5'x4' and also two planked regulators. Catchment area 10 sq. miles. Protection level
21.5. Extent benefited 680 acres.
Mora-Ela (1936), L/12 (8.1 x 7.0), near the 6th Mile Post on Malwana Road. Catchment area 1 sq. mile has two gates 5'x4'; length of structure 45 ft. Level of protection 27.50. Extent benefited 300 acres.
Welgamuwa Minor Flood Protection Scheme (1936); L/12 (9.5 x 6.3) on the 7th Mile Post of Malwana Road has two number 5'x4' gates; length of structure 45 ft. Protection level 30.75. Extent benefited 350 acres.

10,
Giridara Minor Flood Protection Scheme (1954); L17 (11.7 x 0.9) on the Pugoda Road has 6 gates 5'x4'; length of structure 40 ft. Catchment area 4 sq. miles. Area benefited 350 acres.
Nikawela Minor Flood Protection Scheme (1954), L17 (12.5.x 1.8) on the Pugoda Road has 5 gates 5'x4'. Catchment area 5 sq. miles; length of structure 50 ft. Protection level 33.00. Area benefited 225 acres.
Pugoda Minor Flood Protection Scheme L18 (0.1 X2.2), has gates 5'x4'. Catchment area 20 sq. miles; 4 openings 4 x 5' sill 21.5, 4 openings 4'x5' sill 27.5. Area benefited 340 acres. Level of protection 37.75.
Minimaru Minor Flood Protection Scheme (1959), has gates. 5'x4'.
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1.8 COLOMBO NORTH FLOOD PROTECTION SCHEME
A scheme for the protection of the low lands in Colombo North from periodic flooding by the Kelani Ganga, though under investigation much earlier, was commenced in 1925, and completed by 1929.
Railway Embankment, about 2 miles long, comprises the main defence against the Ganga flood waters, connects on to high ground at Meetotamulla; the railway line to Kolonnawa is laid partly on it. Top level about 20 M. S. L.
Lock Gates at Grand Pass-North Lock. A set of four pairs of lock gates across the canal at Grand Pass prevent the Ganga water from entering through the canal.
Main Drain is expected to carry off local rainfall (when lock gates are closed and canal flow to Ganga is blocked up) and is about 2 miles long from St. Sebastian canal at Prince of Wales Avenue to Aluthmawatte. The last stretch of the main drain is by a 6 ft. dia. tunnel, about 1900 ft. long discharging into the sea at the Fisheries Harbour, Mutwal.
Kelani North Bund-originally erected by the Dutch is on the R. B. of the Kelani Ganga and protects the Kelaniya area, across the river on the opposite bank. It is about 5 miles long.
Flood Scheme-Minor Flood Level is reached when the Kelani Ganga reaches a height of 5 feet at the Gauge Post erected at Nagalagam Street, Grand Pass. A flood height of 8 ft. is classified as a Major flood etc.
Standing orders have been prepared requiring each Govt. Dept. to undertake certain functions as the flood level rises in the Kelani Ganga.
52

MNOR PLOOD PROTECTION WORKS
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1.8 COLOMBO NORTH FLOOD PROTECTION SCHEME
RAILWAY EMBANKMENT

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1.9 COLOMBO SOUTH FLOOD PROTECTION SCHEME
A Scheme to protect the low parts of the city of Colombo from periodic inundation by the Kelani Ganga was first considered in 1890-1900 but did not become a concrete proposal till 1922. In 1923 necessary investigations and proposals were made and construction was commenced. The Colombo South Flood Protection Scheme was completed in 1926.
The two gaps through which Kelani Ganga Floods entered the low lands of Colombo South were the:-
(1) Kolonnawa Bund (Heen Ela closure).
This bund connects to high ground at Gothatuwa, Wellampitiya and is 2400 ft. long. Top level is 23 M. S. L.
(2) Dematagoda Ela-Lock Gates
A set of four pairs of Lock Gates erected at Dematagoda, to form a lock, prevent the entry of floods through this ela, nevertheless permitting normal boat traffic.
N. B. See also under Colombo North Flood Protection Scheme.
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1.10 COLOMBO SOUTH DRANAGE SCHEME
Location. The drainage of Swamps in Kotte, Nawala, Battaramulla and Talangamuwa-Southern suburbs of the city of Colombo.
Scheme. About 2000 acres of low lands, which at one time may have formed the estuary of the Kelani Ganga, are to be drained effectively for development purposes. Much of the land is just above sea level and natural drainage through the Dehiwela Canal, and the Kalutara Canal-which are the drainage out flow canals of the area, is sluggish and insufficient.
The flow in the Kalutara Canal is to be accelerated by keeping the sea outfall at Panadura open, by means of groyne walls.
Scheme envisaged includes the provision of pumps to evacuatethe swamps, improvements to Dehiwela Canal with sea groyne walls and Salt Water Exclusion gates and regulated outlet to the
Kalutara Canal.
Eventually it is visualized to drain Colombo South and the Madiwela Catchments, through the Wellawatte Canal, Dehiwela Canal and the Panadura Ganga, into the Ocean.
54

1.11 MUTHURAJAWELA SCHEME
Location
Muthurajawela is a tract of marshy land, about 6,000 acres in
extent, along the western coast lying between North of the Kelani Ganga and South of Negombo Lagoon.
History
It is said to bear the name of King Muthu Rajah, who asweddumized the area in the 13th century. Some say it was so named because at one time it produced pearl like rice even now known as Muthu samba. The Dutch canal was opened by the Kings of Kotte in the 15th century for irrigating rice fields and improving communications. It linked the Kelani Ganga with the Dandugam Oya but unfortunately also led to the unforeseen result of introducing salt water during droughts and floods during rains.
The fields were found abandoned by the Dutch; in the middle of the 18th century however, the lands were partly reclaimed by Dissave de Costa. The chief features of the scheme were:-
(i) A bund in the North known as Tudella-Pamunugama road.
(ii) the Ja-ela canal intended to lead water into the fields from
a tank at Map-eliya, and
(iii) A lock at Mabole controlling the canal in the south.
. These however went into decay and the area relapsed once more to waste lands; the Hamilton Canal was then opened on the West to have water communication with Negombo. Unfortunately. this brought sea water into the area at high tide.
Salt Water Prevention & Flood Protective Works
In 1929 a scheme devised by C. Harward (D. I. E. Colombo Flood schemes) was taken up and the following works were done from 1929 to 1935 and again after a break due to the 2nd world war, the work was continued from 1948 to 1953. ها
(1) Kelani North Bund Scheme (improvements)
Kelani North Bund-4M 3384 ft. (a) Peliyagoda sluice-L/6 (10.6X 1.50) at 3: M. P.-ColomboNegombo road concrete structure 23'-9" long with one
gate 4-3" x 7-3" sill 46.00. (b) Talwatte sluice.
(2) Kalu Oya Muthurajawela Scheme
Wattala bund-L/6(10.70X2.70) at Wattala on left of ColomboNegombo road at 5th M. P. Length 1888 ft. level 59.0 to 58.0, Topwidth 8 ft. sluice at 200 ft, 4 openings 4'-3" x 6' 6"sill 46.00.
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(3) Ja-ela bund-LII (10.90 x 0.70)
Length-1 M-3900 ft., level 58.15 to 56.40. Top width 8 ft. Sluice at 1 MP, 4 openings 4'-3"x6'-6" sill 44.50. (4). , Pamunugana road bund. L/1 (9.30 X0.70)
Along Pamunugama road 1 miles from Ja-ela. Length 3000 ft., level 56.65 to 55.65. Top width 14ft. to 16ft. Sluice No. 1—2 dia. Sluice No. 2—2" dia. (5). Pamunugama diversion bund
Length 470 ft. (6) Bopitiya road gap L/1 (8.8 x 0.5)
On Bopitiya V. C. Road Length 1480", level 54.8. Top width 14ft. at 1400 ft. one concrete pipe 1" dia. with flap gate at sill 51.0
(7) Telengapatha Sluice L/l (10.75 X 2.0)
At 4. M. P. on Colombo-Negombo road Length 29'-6" with 2 openings 4'-3"x6 -14" sill 46.0 (8) Peliyagoda Main drain. (9) Controlled pipes and culverts—3 Nos.
These works were devised for the protection of Kalu Oya Basin and the Muturajawela tracts from the intrusion of salt water and flood water from Kelani Ganga, Kalu Oya and Ja-ela.
Drainage works
The following additional works were then undertaken, for draimage:---
(1) Construction of 28 drainage channels and a channel parallel to Hamilton canal-total length of 20 miles of channel
and bund. (2) construction of 7 salt water exclusion structures. (3) 4 Miles of marginal bunds along Dutch canal.
The drainage channels were connected on the East to the Old Dutch canal and on the west to the Hamilton canal and controlled by Salt Water Exclusion structures. The entry of salt water via Old Dutch canal is controlled by Ja-ela sluice at the north and
Wattala sluice at the south ends.
Additional work in 1956
The following were done:-
(1) Isolation bund at Mabole 1440 ft. long to isolate Kalu Oya catchment (24 sq. mls) from the basin (14 sq. mls). The Kalu Oya water will be diverted to Kelani Ganga through the Wattala sluice.
56

(2) Additional sluice at Wattala to take flood flow.
(3) Old Dutch canal widened from the confluence of Kalu Oya
to the Wattala sluice.
(4) When Kalu Oya and Kelani Ganga are in spate, discharge of Kalu Oya into Kelani is not possible. To cater for this an additional outlet to the sea was provided by installing a sluice on the Isolation bund and letting out the flood water to Hamilton canal via Old Dutch canaland drainage channels.
(5) 6 P. W. D. culverts were widened. The estimated cost of
above is Rs. 1,750,000/-
The Reclamation of the lands below Mean Sea Level, within the Muthurajawela marshes, probably by lift irrigation methods awaits consideration.
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2. BOLGODA BASN
The Bolgoda basin is a low lying coastal basin, typical of the South West coastal basins and located between the Kelani Ganga and the Kalu Ganga. What is usually termed Bolgoda Lake is a long stretch of accumulation of water in the low lands extending continuously from Weerasganga near Dehiwela to Bolgoda Lake North, Bolgoda Ganga and Bolgoda Lake South beyond Panadura. The main supply streams are the Maha Oya flowing into the North Lake and the Bolgoda Ganga flowing into the South Lake. The main sea outlet for the basin is the Panadura Ganga outfall at Panadura.
The catchment area of the basin is 146 sq. miles. The area of water spread of the lakes is 3,775 acres; due to sand bar formation at the Pandaura sea outfall, drainage discharge is impeded and water accumulates in the basin, preventing agricultural development of lands four feet below mean sea level.
Construction work, estimated cost of which is four million rupees, is in hand to erect groyne walls at the Panadura sea outfall to keep the mouth open for free flow throughout the year, as has been done at the Wellawatte outfall. This would help to reclaim about 5750 Acres of low lying fringe areas in the Bolgoda Basin.
The following works in the basin are considered in the pages that follow:-
Attidiya Drainage and Salt Water Exclusion Scheme, Bolgoda Flood Protection Scheme, Galtude Kindelpitiya Drainage & S. W. E. S.
58

2.1 ATTIDIYA DRAINAGE & S. W. E. S.
Location
In Attidiya about 4 miles East of Dehiwela on the DehiwelaPannipitiya Road. Co-ordinates L/11 (11.2 x 1.6).
Scheme
Drainage About a thousand acres of land developed with rice cultivation in Attidiya, suffer damage due to difficulties in drainage, as they are low lands; half the extent is not even two feet higher than mean sea level. The Attidiya canal, the main drainage outlet of the area flows into Weerasganga thence to Bolgoda Lake, which has its sea outfall at Panadura.
At the Southern end of the paddy area where lock gates are provided, pumps are installed which assist in draining the flow when water level in the Attidiya basin has to be lowered for needs of cultivation.
Salt Water Exclusion Salt water which comes up the Weerasganga is prevented from spreading into the 640 acres of cultivated area, through the Ela by providing earthen embankments and 20 ft. long structure containing one way sluices: Openings: Two of 4 ft. by 4 ft.
- One of 4 ft. by 4 ft. and regulators at the road bridges.
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2.2 BOLGODA FLOOD PROTECTION SCHEME
The scheme lies from 3rd Mille Post to 5th Mille Post on the Kalutara - Horana road.
Distance from Kalutara Town is about 5 miles.
Scheme:
Major floods occurring on R.B. of Kalu Ganga have adversely affected low lying lands in Bolgoda area. A flood preventive scheme was provided in 1951.
Main component works of the scheme are:-
(a) Main flood bund 70 chs. long and at further end is the Dikhena flood bund in length 10.4 chs. A closure bund is provided at Kapu Ela lock 7.0 chs. long.
(b) 4 sluices with control arrangements at sites along the main
Bolgoda flood bund.
(c) A sluice with control arrangements at Dikhena gap across
Dikhena flood bund.
(d) One Lock Gate structure across closure bund at Kapu Ela Lock 90 ft. long and 17 ft. wide, with gates and inlet and outlet valves.
Area protected 9000 Acres.

2.3 GALTUDE KNOELPTYA S. W. E. & M. F. P. SCHEME
Location
Along Paraduwa-Horana P. W. D. road upto 4th mile post turn right and proceed along gravel road a distance of about 1 mile to the L. B. of Bolgoda Lake which is L. B. of scheme and ends at Kitulgahawatta Ferry. The R. B. of scheme starts at Bridge No. 6/1 on Waskaduwa-Bandaragama P. W. D. Road and ends at Kitulgahawatta Ferry.
Distance from Kalutara Town is about 15 miles.
Scheme
The Galtude Kindelpitiya tract of 2285 acres of paddy lies on either bank of the Bolgoda Ganga. High tide water along Panadura Ganga heads upto the river and finally inundates the area about the Bolgoda lake and ganga thus causing damage to crops. There are about 20 drainage courses. falling into the ganga from the tracts and these help salt water entry to the cultivated area. -
Main components of the scheme are:-
(a)
(b)
(c)
Salt Water Exclusion bund, 5 miles along L. B. & 6 miles on R. B. of Bolgoda ganga with provision to carry an 8' wide roadway. Bund top level + 5 ft.
Parallel drainage channel along Salt Water Exclusion bund on L. B. & R. B.
Salt water exclusion structures on both L. B. & R. B. with capacity to adequately deal with the discharge of minorfloods totalling 12 in number with batteries of 3'x4' openings.
Area protected 2300 Acres.
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3. THE KALU GANGA BASIN
Description of Basin
The Kalu Ganga also like the neighbouring Kelani Ganga, is a westerly flowing river commencing from sources in the central hills at Adam's Peak at an elevation of over 7,000 feet. A few miles below Ratnapura the Ganga passes through a narrow constriction called the Ellagamuwa Gap. The Ellagamuwa Gap may be considered as separating the upper and lower regions of the basin. The Ganga is 82 miles long.
Hydrology
The Ganga drains some of the heaviest precipitating areas of Ceylon near Ratnapura. The average annual rainfall in the catchment is about 160 inches, of which over 90 inches precipitate during the months of May to June. The maximum volume of flood that had gone down the Ganga is assessed at two million acre feet, during a period of two weeks flood duration.
Kalu Ganga in Flood
The Kalu Ganga is a most prolific provider of flood waters; though only 80 miles long, Kalu Ganga is No. 1 in the annual amount of water conveyed by the river into the sea, an aggregate of over 6 million acre feet of water empties into the Indian Ocean to waste every year.
When in flood, Ratnapura town is affected and some houses go under water. The flooding is more damaging in the lower reaches where the gradient of the river is flatter. Several flood protection schemes against minor floods have been resorted to, to isolate and protect pockets near the coastal regions in the neighbourhood of Kalutara.
Land Use -
The entire basin is well developed; tea is grown in the areas. generally about 2,000 feet in elevation and above; then rubber and coconut and rice in valleys of the lower region:
Tea 35,000 acres Rubber 143,000 Coconut 30,000 Rice 63,000
The Ratnapura District is the main gem producing area of Ceylon and high quality graphite is also mined there.
The following is the list of some of the development works, details of which are given in some cases with illustrations in the next pages.
Batugedera Anicut Damme Ela Kalutara South Flood Protection Scheme Palatota Scheme-Kalu Ganga Flood Protection Scheme Paraduwa-Diyagama Minor Flood Protection Scheme. A flood protection scheme for this basin has been investigated and reported on by Engineering Consultants Incorporated.
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3.1 BATUGEDEIRA ANICUT
Location
Near Ratnapura; anicut near 66th Mile Stone on the Ratnapura-Pelmadulla Road. Co-ordinates L124 (7.8x7.3).
Historical
Local tradition associates this work with Ellapola, a Minister of the last King of Kandy under whose direction, the amuna is said to have been first erected.
Restoration
The work was restored in 1889 by the construction of a permanent anicut across Dodangaha Ela and Ketandola Ela and channel system.
Later improvements were effected in 1947 and in 1953, and concrete lining of the channel etc. was done.
Data Anicut Diversion
Catchment area 6.2 sq miles
Main Anicut (Dodangaha Ela)
Length of Structure 131 ܀ ft. Height 2ft. Head Sluice 5”×2”
Pick-up Anicut (Ketandola)
Length of Anicut 63 ft.
Height 22 ft.
Head Sluice 5'-3”×1"
Irrigation Supply.
About 2 miles of main channel system provide over 200 acres with supply for irrigation development.
The channel skirts the main road for some distance and can be seen near the 65th Mile Stone.
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3.2 DAMME ELA
Location
Near Ratnapura, South West about 10 miles. Co-ordinates I/24(2.6×65)
Restoration
Said to have been restored or constructed in 1876 by private individuals.
Scheme
In 1952, the work was acquired by Government, and improvements effected.
Anicut Diversion of flow in Niri Ela Ganga.
Data
Anicut
Catchment area 35.6 sq. miles Length of Structure 200 ft. Maximum Height 4 ft. Planked Bays 3 Nos. Head Sluice:
Location L. B. Size 6”×2-9”
irrigation Supply
A five mile long left bank channel mostly in deep cutting, commands lands in Elapatha, Dellaboda and other areas. Target for development 425 Acres.
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3.3 PARADUWA-DYAGAMA MNOR FLOOD PROTECTION SCHEME
Location:
From Nagashandiya junction along Horana Road and turn right at 2 miles along Galkande Road and about a mile to project. About 5 miles from Kalutara. Co-ordinates: L/22 (5.7x5.3)
Scheme
The paddy lands in the villages of Paraduwa, Diyagama & Panapitiya on R. B. of Kalu Ganga were affected by the floods of the ganga.
Main components of the scheme
A flood bund 4100 ft. long has been constructed on the right bank of Kalu Ganga, along the 3rd, 4th & 5th miles of the river.
5 Nos. structures have been provided with Screw operated gates along the bund at Nala Ela, Kalugoda Ela, Ukule Ela, Liggala Ela and Aluth Ela. A natural spilway 300 ft. long at chainages 30-33, a short bund at spillway 300 ft. in length, a closure bund to close gap at Goraka Ela to a higher level 135 ft. long has been constructed. Another additional bund 700 ft. long is constructed at a higher level
across Palli Ela to shut off flood water entering the Diyagama Basin.
The bunds and structures act as a minor flood protection scheme on the R. B. of Kalu Ganga. Protecting an area of about 411 acres of Paddy Lands. The scheme was constructed in 1958/59.
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34 PALATOTA BASIN
KALU GANGA FLOOD PROTECTION SCHEME
Location
Proceed towards Kalutara on Colombo-Galle Road, turn
left at Kalutara Clock Tower junction and proceed one mile along Palatota-Kethena P. W. D. Road.
Co-ordinates L/22 (2.8X2.5).
Scheme
The low lying area on the U/S of Kalutara-Kethena Road has been frequently subjected to minor floods of Kalu Ganga on the left bank and on representation made by the land owners this scheme was devised to protect an area of about 60 acres under Kalu Ganga flood protection schemePalatota Basin.
Main components of the scheme are:
(a)
(b)
The main flood bund has been constructed on L. B. of Kalu Ganga by raising the Kalutara-Kethena P. W. D. road to a length of 14.25 chains and connecting bunds on either ends 1.0 chains and 2.9 chains forming ramps.
A bridge cum sluice with lifting gates to control flood waters has been provided across main bund at 5.5 chains. A culvert 2 feet d has been provided at 8.5 chains across main bund , to act for drainage purposes. The work was done in 1958.
Area protected: 60 acres.

3.5 KALUTARA SOUTH FLOOD PROTECTION SCHEME
Location:
Kalu Ganga. About a quarter mile towards Palatota, from Kalutara.
This scheme is for the protection of the low lying lands in the neighbourhood of Kalutara south L. B. of Kalu Ganga in the banks of Aluth Ela.
Co-ordinates L/22 (2.6X2.2).
Data
Length of bund from P. W. D. Road Bridge to River side Road 32.0 chs.
Structure
(a) One sluice is provided at 2.5 chs on the bund with control
(b)
arrangements and opening 8'-0"X6'-0" inclusive of 3'h Severage Outlet with automatic gate on one side of structure at 2.5 chs. Another sluice is provided across River side Road at Aluth Ela gap with seven openings 4' d with control arrangement gates of 49' x 4'9" at 19.0 chs.
Area protected: 260 acres.
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4. BENTOTA GANGA BASIN
The Bentota Ganga has its source in the one thousand feet hilly plateau above Pitagala and following a 30 mile long westerly course reaches the sea at Bentota, near Alutgama.
Hydrology
The Bentota Ganga drains an area of 243 square miles, in which an annual average rainfall of over 100 inches can be expected, spread over almost all the months of the year, usually prevalent in the wet zone. Mean annual flow is estimated at 810,000 acre feet.
Floods
Frequent inundation by periodic floods impose hardship on the land owners and retard agricultural development.
Land Use
Except in the very low reaches near the coastal belt the basin is planted with rubber. In the lower reaches coconuts and some paddy can be seen.
The basin is typical of the coastal basins along the south western coast of Ceylon.
Basin requirements
Flood Protecton
During times of flood, the ganga overflows the banks in the lower
reaches and inundates adjoining low-lying lands. These lands
require protection.
Land Drainage
Speedy internal drainage of these lands is the key note for its development, without which the area remains as marshy lands. The position is aggravated by the blockage of the ganga sea outfall by sand bar formation. ـــــ
Salt Water Prevention
When flow in the ganga subsides, sea water enters the ganga and intrudes into the adjacent low-lying lands rendering them brackish and unsuitable for agricultural development. S. W. E. sluices and gates are needed to prevent such intrusion.
Inland Fisheries and Prawn Culture
This basin, like several other basins similarly situated along the south-west coast of Ceylon, with inland lakes and water-ways, provide scope for development of inland fish and prawn culture. Development works in the basin consist mostly of salt water exclusion schemes to prevent ingress of sea water which travels up the river. Details of some of the S. W. E. Schemes follows:-
4.1 Dedduwa 4.2 Kavijapitiya 68

4.1 DEDDUWA DRANAGE AND SALT WATER EXCLUSION SCHEME
Location
Adjoining the 39th to 42nd Mile Post on Colombo-Galle Road.
Scheme
To prevent ingress of sea water which enters through the Bentota Ganga and also to facilitate drainage of the area.
Restoration
Constructed in 1945.
Drainage Works
1. Dedduwa Regulator and Bund O/7 (6.5 x 7.5)
Regulator-4 bays of 4 ft. each. Bund–650 ft. 2. Andu Ela Drainage Culvert O/7 (7.3 X 7).
Opening 2"x2". 3. Obadawatte Regulator O/7 (5.1 x8.4).
Drainage channel 1 miles.
Salt Water Exclusion Works
l, Aturwell; sea outfall structure O/7 (5.4X6.6).
()penings: 4 of 2-3" - 2'-3". Channel--.910 ft.
2. Kaikawela sca outfall structure O/7 (5.6X5.1).
Openings: 4 of 2'-3"x2'-3" each. Channel-610 ft.
Irrigation Supply
The work aids development in 2100 acres by drainage and prevention of ingress of sea water.
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4.2 KAVJJAPITYA DRANAGE AND SALT WATER
EXCLUSION SCHEME
Location
Near the 47th mile Colombo-Galle Road.
Co-ordinates O/7 (7.0 x 1.5)
Scheme
The Kavijapitiya Ela is the main drainage of a basin of about 400 acres; agricultural development of this basin is handicapped by (1) insufficient and slow drainage of the Maduganga lake and (2) the ingress of salt water. New work constructed in 1944 to alleviate these difficulties have been:-
1. A mile long drainage channel connecting Kavijapitiya Ela direct to the sea, crossing Colombo-Galle Road by culvert No. 47/3.
2. Sea outfall works at exit of channel consisting of 4 openings of double one way flap gates 2'-3"x2'-3" with channel cut in rock, deflector and chamber, 100 ft. long.
3. Culvert cum Regulator on Madu Ganga intake: 2 openings of 12'-3"x 7" with planking arrangement.
Irrigation Supply
70
The scheme benefits an extent of 362 acres with drainage facilities and prevention of ingress of sea water.

5. MADU GANGA BASIN
The Madu Ganga basin is a small area of 23 sq. miles in the West Coast, and enters the sea near Balapitiya. The sea outfall is usually closed by a sand bar; hence the chief work in the area is the Drainage and Salt Water Exclusion Scheme which was commenced
in 1964.
MADU GANGA DRANAGE AND SALT WATER EXCLUSION SCHEME
Location h−
Area on the East of the 49th mile, Colombo-Galle Roa Co-ordinates O112 (7.4x6.9)
Scheme
About a 1000 acres of developed land and swamps about 200 acres, which border the outer fringes of Madu Ganga Lake and the Ramtombe Lake, suffer due to insufficient drainage and cultivation is impaired. The sea water that travels up Madu Ganga also renders the area saline.
Construction work, for the project, provides:
(l) Reconditioning and regrading the internal drainage channels
within the area.
(2) Training the sea outfall at the mouth of the Madu Ganga with groyne walls into the sea, to prevent sand bar formation and facilitate daily flow out of the Ganga.
(3) Salt Water Exclusion structure to prevent sea water intrusion
into Madu Ganga.
The work incidentally provides safe anchorage for the fishing craft in calm waters secluded away from the rough seas.
Approximate cost Rs. 2 million.
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6. MADAMPE LAKE BASIN
MADAMPE LAKE DRANAGE AND SALT WATER
EXCLUSION SCHEME
Location
Near Ambalangoda, about the 54th mile on Colombo-Galle Road.
Co-ordinates O/12 (8.8x3.2).
Scheme
72
About 3500 acres of developed land that border the fringes of Madampe Lake suffer:-
(1) periodic inundation, as the lake does not always speedily discharge flood waters into the sea due to sand bar formation at the mouth.
(2) Salinity, due to sea water intrusion into the lake.
Construction work at the site provides:-
(1) Sea groyne walls at river mouth to assure permanent functioning of the river flow into the sea by the prevention of sand bar formation at the mouth.
(2) Reduction of rock at river mouth to facilitate rapid outflow of basin drainage.
(3) Salt water exclusion structure to prevent sea water intrusion into Madampe Lake.
The work incidentally provides safe anchorage for fishing craft in seclusion away from the rough seas.
Total cost Rs. million.

7. HKKADUWA ELA POST FILOOD DRANAGE SCHEME
Location
At Hikkaduwa, adjoining 61st mile on Colombo-Galle Road.
Co-ordinates Of 18 (11.6x6.9),
Scheme
Hikkaduwa Lake collects drainage from water shed area of 23 sq. miles and discharges into the sea through the Hikkaduwa Ganga (Bridge No. 60/1). Due to sand bar formation at the mouth of Hikkaduwa Ganga, this is possible only when floods are high. Normal floods, however accumulate in Lake and the rising water level periodically inundates over 650 acres of developed land, bordering the fringes of the lake. Attempt has been made to relieve such accumulation on these occasions, by the opening up of a drainage channel 1 miles long through Madabokka, from the lake to the sea direct, independant of the Hikkaduwa Ganga. This channel (crosses Colombo-Galle Road at bridge No. 62/1) is provided with salt water exclusion structure and helps in the lowering of water level in the Hikkaduwa Lake, on normal rainy days even when the sand bar at the Ganga mouth fails to open. Completed in 1960.
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9. THE GEN GANGA BASIN
The Gin Ganga, situated in the south-western region of Ceylon, and drains an area of 370 sq. miles. The Ganga is over 70 miles long; with its source at Abbey Rock (El: 4268), the river passes Udugama, Baddegama and flows into the sea at Gintota. The last stretch of 15 miles is through flat plains.
Hydrology
The region is essentially a south-west monsoonal area and floods are experienced during that period. The average annual flow into the sea is about 1 million acre feet and the mean annual rainfall about 130 inches.
Land Use
The basin is fairly well developed; the upper hill country region is planted with tea and rubber; coconut and cinnamon plantations predominate in the lower areas. Paddy lands are in pockets all along the ganga, amounting to about 28,000 acres. About half of this situated in the lowlands suffer from periodical floods.
An effort has been made to protect certain pockets of areas from floods by means of earth bunds, but without satisfaction.
A flood absorption reservoir higher up the river at Hiniduma and or at Madugeta has been suggested.
Basin Requirements
Foremost requirements is flood protection-prevention of the lands in the lower reaches from periodic inundation by flood waters
of the Gin Ganga. Therefore construction of flood absorption reservoirs is the indication.
Preliminary Planning of Water Resources Utilisation
Several stream diversion works have been carried out in the basin for irrigation supply to paddy cultivation, details of one of these follow; details of the flood protection scheme for the protection of the adjoining lands from minor flood in the Gin Ganga are also shown with illustrations in the next pages.
3.91 Bogahaduwa anicut. 3.92 Gin Ganga Minor Flood Protection Scheme.
A flood protection Scheme for this basin has been investigated and reported on by Engineering Consultants Incorporated.
74

9.1 BOGAHADUWA ANICUT
Location
About a mile East of the 5th mile on the Galle-Baddegama Road. Co-ordinates Of 18 (6.2X3.0)
Restoration
Constructed in 1954.
Scheme
Diversion of flow in Holuwegoda. Ela.
Data
Anicut
Catchment area 17. sq. miles Length of Structure 52'-3" Openings 7 NOS.
Each 5'-6" wide by 7'-6" Sluices:
Location R. B. Size l5 ins dia.
Irrigation Supply
The work benefits rice cultivation in 225 acres of land situated along the bank of Holuwegoda Ela.
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9.2 GN GANGA MNOR FLOOD PROTECTION SCHEME
The Gin Ganga is a 70 mile long river in the South West of Ceylon, with its source near Deniyaya-4000 ft. elevation and falls into the sea at Gintota, a few miles from Galle. The area lies directly in the path of the South West monsoon and experiences very heavy rainfall.
In the lower reaches, the Gin Ganga valley is about a mile wide and about 12,000 acres are under rice cultivation. These lands which are situated in the basins suffer from periodic inundation due to floods in the Ganga.
A flood protection scheme has been promoted for the area, which has as criterion the prevention of floods up to 18,000 cusecs in the Ganga, which corresponds to a height of 18.2 ft. at the Gauge near Aggalia-a few miles from Baddegama.
Earthen embankments prevent the ingress of Ganga floods into the protected basins; the control sluices permit basin drainage into the Ganga when it is low. The spill is for permitting floods in excess of minor floods to enter the basin. Lock gates are provided where necessary.
Basins in the LeftBank Basins in the Right Bank 1. Puhulduwa Basin 1. Majuwana
Area protected 3354 acres Area protected 307 acres. 2. Gotetuwa 2. Dodangoda
Area protected 128 acres. Area protected 326 acres. 3. Ganegama Basin 3. Kudawe Ganga
Area protected 314 acres. Area protected 2630 acres.
4. Holuwegoda
Area protected 3550 acres.
5. Kepu Ela
Area protected 346 acres.
76

10. KOGGALA BASIN
WAGGALAMODERA DRANAGE AND SALT WATER
EXCLUSION SCHEME
Location
At Talpe, near 77th to 79th miles, Colombo-Galle Road. Co-ordinates 0/23 (10.1 x 5.5)
Scheme
A Scheme for the reclamation of Waggalamodera lands was
constructed by the P. W. D. in 1889.
The Habaraduwa tract of paddy fields, about 600 acres in extent, situated between the 77th and 79th miles of ColomboGalle Road, annually suffer inundation by flood waters and
also become uncultivable due to salt water entry.
The Waggalamodera Drainage and Salt Water Exclusion Scheme consists of improving the conditions of above and
hence aiding development.
The work consists of:-
1. Waggalamodera new Drainage Channel discharging low water drainage, through culvert No. 7813 into the sea, with a
sea outfall structure.
2. Eluwila Main Drainage Channel discharging accumulation of water ponding up in the basin, through structure No. 8012 on Galle-Matara Road. This functions only when
there is a big flood and the sand bar is therefore open.
Scheme was completed in 1939.
Irrigation Supply
The scheme benefits an extent of 60l acres.
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11. POLWATTA GANGA BASIN
11.1 POLWATTA GANGA NUNDATION REGULATOR Location
Situated about 4 miles North of Welligama. Co-ordinates OI24 (6.8x6.8)
Scheme
By the erection of a regulator across Polwatta Ganga, the flow in it is headed up and diverted for cultivation.
Constructed in 1954.
Data
Diversion Regulator
Catchment area 82 sq. miles Length of Structure 100 ft. Height 2 ft.
Three Openings each 20 ft. wide by 12 ft. high with overhead bridge and steel gates and lifting gear.
Irrigation Supply
The work aids the development of 1135 acres of rice cultivation, situated in Jamburegoda and Palalla paddy tracts.
The Polwatta Ganga has its source above Nakiyadeniya, where it is known as Udugan Oya. It has a catchment area of 91 sq. miles and traverses nearly 20 miles before flowing into the sea at Welligama Bay. The upper reaches of the Basin are planted with rubber and some tea. In the lower reaches the Ganga flows through large stretches of rice lands. An important development work is the Polwatta Ganga Inundation Regulator. This work is supplemented by a diversion anicut at Tottegedora.
78

3.3 STRUCTURE AND GATES PARADUWA-DIYAGAMA SCHEME
6. MADAMPE SCHEME S.W.E. STRUCTURE

Page 50
11.1 POLWATTA GANGA REGULATOR
11.3 SEA GROYNE WALLS GOIYAPANA SCHEME
 
 

11.2 HALLOLA DOLA ANICUT
Location
Situated off the Welligama-Kananke Road.
Co-ordinates O24 (8.4X 7.0)
Restoration
Constructed in 1961-63.
Scheme
Utilisation offlow in Hallola Dola.
Data
Amicut
Catchment area 1 Sq. mile Length of Structure 50ft。 Openings: - 2 Nos.
Each 5 ft. by 5 ft.
Storage 80 ac. ft. Sluices:
Location . L. B.
Size 24" dia. to parent stream.
Irrigation Supply
The work aids rice cultivation in 200 acres extent, situated in Hallola village. Tanks in this bimonsoonal zone receives replenishment several times in a year unlike the dry zone where only one annual replenishment can be expected.
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11.3 GOYAPANADRANAGE AND SALT WATER EXCLUSION SCHEME
The Goiyapana basin is an adjoining (West) minor basin of the Polwatta Ganga.
Location
Scheme
Near Welligama, the sea outfall adjoins bridge No. 8612 on Galle-Matara Road.
Co-ordinates OI24 (4.0X3.2)
About 800 acres of developed land, situated in the fringes of the Goiyapana Ganga, are difficult to cultivate due to: (1) Periodic inundation by the Ganga waters, as the mouth of the Ganga at the sea outfall gets closed by sand bar formation.
(2) Salinity, due to sea water intrusion up the Goiyapana Ganga.
Construction work provided at the project includes:
80
(1) Two sea groyne walls at the Ganga mouth, which prevent sand bar formation, facilitate daily flow of the Ganga and rapid discharge of floods from the basin.
(2) Salt water exclusion structure to prevent ingress of sea Water.
Completed in 1960.

12. N LWA LA GANGA BASIN
The 45 mile long Nilwala Ganga, draining an area of 375 sq. miles, is in the southern sector of the Island and flows into the sea at Matara, after passing Akuressa and Morawaka higher up.
Hydrology
The entire basin is in the south monsoonal zone and experiences an average rainfall of 115 inches. Flood occurrence is fairly frequent during the monsoon. Annually about a million acre feet of water reaches the sea to waste, through the Nilwala Ganga.
Land Use
About a third of the basin, forming the uppermost region, is in luxuriant jungle; then the tea and the rubber plantation areas, followed by coconut, citronella and cinnamon areas are situated below.
Cultivation of rice is quite extensive in the basin amounting to about 40,000 acres.
A minor flood protection project consisting of earthen embankments and drainage gates has been attempted to protect cultivated areas in the lower region. This has not been very satisfactory.
Basin Demands
The cultivated lands (40,000 acres) in the lower reaches suffer by inundation due to periodic flooding by the Ganga. The demand of the basin is the alleviation of this distress, consistent with efficient drainage and irrigation supply when needed.
Preliminary Planning of Water Resources Utilization
As an all-purpose satisfactory solution, it has been suggested that multi-purpose flood detention reservoirs be constructed in the upper reaches of the valley, one each across the two tributary streams, Urubokka Ganga and Hulandawa Ganga.
A flood protection Scheme for this basin has been investigated and reported on by Engineering Consultants Incorporated.
81

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12.1 HALELA TANIK
Location
Is situated about 1 miles West of Kamburupitiya Junction, which is 11 miles North of Matara.
Co-ordinates O/20 (1.6 x 2.5)
Restoration
Present tank restored in 1871.
Data
Tank
Catchment area 3 miles Length of Tank Bund 320 ft. and 170 ft.
Tank Full:
Storage 3000 acre ft. Head of water 25 ft. Area of water spread 300 acres Spills:
Width 116 ft. and 86 ft.
Sluices:
3 Nos.
irrigation Supply
Channel system over three miles long provides supply for 306 acres of rice cultivation.

12.2 ELLAWELA TANK
Location
Is situated in Ellawela village, about 2 miles North East of Kamburupitiya Junction which is 11 miles North of Matara. Co-ordinates O120 (5x3.5)
Restoration
Present tank restored in 1876.
Data
Tank
Catchment area - 2.2 Sq. miles Length of Tank Bund 360 ft. Tank Full:
Storage 800 acre ft. Head of water 30 ft. Area of water spread 65 acres Spills:
Natural, channel 42 ft. wide.
Sluices:
24 ins. dia.
Irrigation Supply
Channel system over 1 miles long provides supply to 1613 acres for rice cultivation. Unlike in the dry zone, tanks in these bimonsoonal areas receive replenishment more than once in a year.
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12.3 DANDENIYA TANIK
Location
In Dandeniya village, about 4 miles North West of Dickwellaturn off near 109 M. P. on Colombo-Tangalla Road and proceed three miles.
Co-ordinates O/25 (9X5)
Restoration
Present Tank restored in 1884.
Data
Tank
Catchment area - 2 sq. miles Length of Tank Bund 250 ft. Tank Full:
Storage 750 acre feet Head of water 30 ft. Area of water spread 50 acres Spills:
Natural, channel 84 ft. wide.
Sluices:
L. B. Masonry Tower Sluice with 24" dia. pipe.
Irrigation Supply
Left Bank channel about 3 miles long and a short channel on the Right Bank, together aid rice cultivation in 626 acres. Unlike in the dry zone, tanks in these bimonsoonal areas receive replenishment more than once in a year.
84

12.4 SAPUGODA ANICUT
Location
About half a mile West of Kamburupitiya, a village 11 miles North of Matara.
Co-ordinates O120 (2.7x2.4)
Restoration
Present work constructed in 1874.
Scheme
Diversion of flow in Kirama Ara, a tributary of Nilwala Ganga.
Data
Anicut
Catchment area 53 sq miles Length of Structure 20ft. Height 5' - 6° Openings one Plank Contro- 3'X.5' Head Sluice:
Size 3”×5'
Irrigation Supply
A short channel 900 ft. long benefits 382 acres with irrigation supply for rice cultivation.
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12.5 URAPOLA ANCUT
Location
About 9 miles North of Matara on the Road to Kamburupitiya.
Co-ordinates O/25 (2.6 x8.6)
Scheme
Diversion of flow in the Kirama Ara, i a tributary of the Nilwalla Gan ce.
Data
Anicut
Catchment area 69 sq miles Length of Structure 24 ft. Height 5ft,
Head Sluice:
Size 11”-6”×6'-8”
irrigation Supply
A five mile long channel system commands irrigation supply to 1500 acres for development with rice cultivation.
86

12.6 KEKANADURA TANIK
Location
Is situated in Kekanadura village, which is 4 miles North East of Matara.
Co-ordinates O125 (5X4)
Restoration
Present work restored in 1871.
Data
Tank
Catchment area 3 sq. miles Length of Tank Bund 425ft, Tank Full: -
Storage 2300 acre ft. Head of water 35 ft. Area of water spread 210 acres. Spili:
Natural channel 50 ft. wide.
Sluice:
Masonry Tower with two openings each of 24" dia.
irrigation Supply *
Channel system with over 5 miles of main channel and the branch channels to Indopitiya, Ranaliya, Talpawila, Mahawita and Mahakanda totalling 7 miles, provide irrigation supply to 1165 acres for rice cultivation.
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12.7 NAGODAWETYA INUNDATION REGULATOR
Location
At Narangola, a village about four miles South East of the 5th mile on Matara-Akuressa Road.
Co-ordinates O/25 (1.0 x8.1) Constructed in 1962/63.
Scheme
Heading up of flow in Badulu Oya for irrigation by inundation.
Data Anicut
Catchment area 7.8 sq miles Length of Structure 30 ft. 6 ins. Openings: 4 Nos.
Each 5'-6" wide by 6'-6" with lifting gates Sluice:
Size 18 ins. dia.
Irrigation Supply
The work is intended to benefit, by inundation about 750 acres of land for rice cultivation, situated along the banks of Badulu Oya, in Narangola village area.
88

12.8 NILWALA GANGA MINOR FLOOD PROTECTION SCHEME
In the lower reaches of the Ganga commencing from about Paraduwa to the sea about, 13,000 acres are developed with rice cultivation. These suffer due to periodic inundation by Ganga floods.
The Nilwala Ganga Minor Flood Protection Scheme envisages the prevention of minor floods up to the magnitude of 11,800 cusecs (corresponding height 23.5 ft. at the Akuressa Gauge), from entering the four basins of the rice area by means of bunds, spills, control sluices, lock gates and irrigation sluices.
Basins on Left Bank of Ganga Extent of Rice cultivat
ed area for protection 1. Badulu Oya Basin 3,550 acres 2. Kadawedduwa Basin 4,270 ,
Basins on Right Bank of Ganga
1. Katuwangoda Basin 1.110 ,, 2. Lenaduwa Basin 2,470 ,
Construction of the Scheme was terminated pending further investigations.
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14. KIRAMA OYA BASIN
he Kirama Oya, has its source near Kirama village and flows through Walasmulla area and has its outfall into the sea at Tangalla.
The Kirama Oya Irrigation development scheme, the earliest irrigation work to receive the attention of the British (original work was by the Dutch) breached in 1837 and was restored in 1858-1875. at a cost of Rs. 94,603, for the maximum utilisation of the oya catchment drainage, by a detention storage tank in the upper reaches-theKirama Tank, and effecting diversion of flow in the parent oya at various selected sites, all along the 20 mile long stretch of the Kirama Oya, for irrigation supply for the cultivation of 3625 acres. Each anicut has its own diversion channel system for conveyance of
supply.

14.1 KIRAMA TANIK
Location
In Kirama village about 20 miles North West of Tangalla.
Co-ordinates Ol 5 (8.9 x 2.8)
Data
Tank
Catchment area 5 Sq. miles Length of Tank Bund 750ft。 Tank Full:
Storage 450 acre ft. Head of water 6 ft. Area of water spread 90 acres
Spills:
At L. B. 22 ft. Masonry At R. B. 80 ft.
Sluice:
Two openings 6'X6' Irrigation Supply
About 400 acres of rice cultivation is directly fed from the tank.
91.

Page 57
KIRAMA OYA BASIN
14.2 DIVERSION ANICUTS
1. Hambumandiya Anicut O/15 (12 X0.6)
Catchment area 20 sq miles.
Length of Structure 36 ft.
Height 7ft。
Irrigates 210 acres 2. Ethpitiya Anicut O| 15 (11.7 X0.1)
Catchment area 19.7 sq. miles.
Length of Structure 43 ft.
Height 11 ft.
Head Sluice 5”×5'-3”
Irrigates 200 acres 3. Uda Deberawa O/20 (11.8 X7.2)
Catchment area 20.7 sq miles.
Length of Structure 85'-6"
Height 9ft。
Irrigates 180 acres 4. Arachchi Amuna O/20 (11.9 X 6.7) .
Catchment area 25.1 sq. miles.
Length of Structure 54ft。
Maximum Height 11 ft.
Irrigates 310 acres 5. Okawela Anicut O/20 (13.2 X 4)
Catchment area 29.4 sq miles.
Length of Structure 29'-6"
Height V− 7 ft.
Irrigates 520 acres
6. Pattiyawela Anicut P/16 (0.1 X 2.5)
Catchment area Length of Structure
32.6 sq. miles.
37'-6"
Height 7ft。 Irrigates 274 acres 7. Kahawatta Anicut P/16(0.9X 1.6) V
Catchment area 66.6 sq. miles. Length of Structure 40 ft. Height 10 ft. Sluices 3 Nos. Irrigates 165 acres and three others:-
Nalagama P/16 (2.8 x 1.7)
Maha P/16 (4.1 x 0.3) and Danketiya P/21 (4.8x6.3)
92

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Page 58
12.1 HALIELA TANK
12.4 SAPUGODA ANICUT
 
 

14.3 DENAGAMA TANIK
Location
Is situated at Hakmana, about 13 miles North East of Matara. Co-ordinates OI20 (8.3 X 4.3)
Restoration
Present tank restored in 1876.
Data
Tank
Catchment area 3 sq miles Length of Tank Bund mile. Tank Full:
Storage . 840 acre ft. Head of water 14 ft. Area of water spread 80 acres
Spills:
Natural, channel 90 ft wide.
Sluices:
3 Nos. słuices.
Irrigation Supply
Two short channel systems aid rice cultivation in 850 acres. Unlike in the dry zone, tanks in these bimonsoonal areas receive replenishment more than once in a year.
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14.4 TANGALU WELYAYA SALT WATER EXCLUSION SCHEME
The Tangalu Welyaya tract of paddy fields are adjacent to the . 124th mile on the Colombo-Hambantota Road, about a mile out
of Tangalla.
The tract is about 1200 acres in extent of which about 600 acres are low, being only a foot above sea level.
Waters from the Kirama Oya Scheme, diverted by the Maha Amuna and Danketiya anicut help the cultivation of the paddy tracts. But sea water enter the tract through the Rekawa Kalapuwa and retard development in the lower areas in particular.
The Salt Water Exclusion Scheme consists of:- (1) Salt Water Exclusion Bund along the Kalapuwa confining
it, without spreading all over the fields. (2) An 8 bay Regulator up-stream of Bridge No. 124/6.
(3) A 5 bay Regulator up-stream of Bridge No. 124/7 and other
works, which were constructed in 1946.
These assure that no salt water from the Rekawa Kalapuwa reach the paddy fields.
They nevertheless retard the discharge of flood waters that accumulate in the Tangalu Welyaya basin from the Kirama Oya and further measures e.g. sea groyne walls are necessary to assure steady flow out of drainage from the basin.
94.

16. URUBOKK8 OYA BASIN
The Urubokke Oya has its source at Urubokka, a village 40 miles "directly North of Matara. The oya is formed at the source as a re ult of a diversion by a massive masonry dam across a perennial hill country stream. The oya then traverses a long stretch of nearly fifty miles draining 136 sq. miles to reach the sea at Ranna, near 130th M. S. on the Hambantota Road.
The drainage waters of the basin are well utilised for irrigation 'development by means of detention storage tank at Udukiriwila and several anicut diversion schemes all along the course of the Oya.
One of the earliest irrigation works to be restored by the British in 1861-original work was by the Dutch.
A total extent of 5,100 acres are thus developed in the basin and receive irrigation supply for regular rice cultivation.
Historical
One of the few irrigation works constructed by the Dutch; it was breached in 1837 for want of proper maintenance. The restoration of the scheme was again put in hand 1859-62 and completed at a cost of Rs. 407,302.
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16.1 URUBOKKE DAM
Location
At Urubokka, about 40 miles North of Matara. Co-ordinates O/10 (7.3x0.7)
Data
Catchment area 9 sq miles Length of Structure 160 ft. Maximum height 38 ft. Top width 13 ft.
A 2 mile long channel conveys water to Ginnely Oya stream to form Urubokke Oya.
96

16.2 UDUKIRIWELA TANK

Page 61
16.2 FOUR BAY ANICUT FEEDING UDUKIRIWELA TANK
16.3 ANDUPELANA ANICUT
 
 

URUBOKKE OYA SCHEME
16.2 UDUKIRIWELA TANK
Location
Situated at Weeraketiya, about 10 miles North of Tangalla. Co-ordinates P/16 (3.4x8.0)
Scheme
The Udukiriwela Tank is the fundamental means of irrigation detention storage and supply for development in the Urubokke Oya basin. Inflow is diverted for storage, from Urubokkhe Oya by Udukiriwela anicut.
Data
Talk
Source of Supply:
Diversion from Urubokke Oya and catchment drainage from 10 sq. miles. Length of Tank Bund 3300ft。 Tank Full:
Storage 3200 acre ft. Head of water 12 ft. Area of water spread 650 acres Spills:
Nature Channel flow Length 70ft。
Sluices:
No. 1 With one 24” dia. opening. No. 2 With two openings.
Irrigation Supply
Water stored in the tank ultimately reaches 4,150 acres, being let down into the parent stream and diverted by anicuts of the Urubokke Oya Scheme.

Page 62
URUBOKKE OYA SCHEME
16.3 DIVERSION ANICUTS
Udukiriwila Anicut P/16 (3.6 X8.3)
Catchment area 20 sq. miles Length of Structure 65'-6" Bays-three, 15 ft. wide each Height 5. ft.
Irrigates 700 acres
Wakumulla Anicut P/16 (4.5X7.4)
Length of Structure 41 '-6" Bays-five, 6'-6" wide Height - 7'-6" Irrigates 760 acres
Hakuruwela Anicut P/16 (7.5X7.2)
Length of Structure 37ft, Bays-five, 6 ft. wide Height - 6 ft. Irrigates M 550 acres
Andupelena Anicut P/16 (8.4X4.8)
Catchment area 108 sq miles Length of Structure 4'-6" Bays-five, 6 ft. wide Height 7 ft. Irrigates 800 acres
Ranna Anicut P/16 (0.9 X3.4)
Catchment area 110 sq miles Length of Structure V− 38 ft. Bays-five, 6 ft. wide Height 7ft, Irrigates 270 acres
Pattiyapola Maha Wewa P/16 (4.3X2.5)
Catchment area 16 sq. miles and supply from Udu
kiriwila Tank Bund-Length 4000ft,
Storage 570 acre ft. Head 9ft。 Spills-Two, 250 ft. long and 85 ft. long Sluices—4 Nos. s
Irrigates 450 acres. 98

A NI CUTS ACROSS
U RUBOKKE OYA
ADMINI MW11. A ANICU.
WJOU WARA TA
wirAx er vi
té !YAPOLA AHA WE YA..
ScaLE:- ON INCN to Four MILEs (Approx)

Page 63
18.1 UGGALKALTOTA L.B. CHANNEL HEAD SLUICE
 

16.4 MURUTHAWELA SCHEME
Location
Near Muruthawela village about 12 miles North of Tangalla. Co-ordinates P/11 (0.5X2.4)
Project
A new storage reservoir to impound the waters of Urubokke Oya.
Tentative Data
Tank
Catchment area 136 sq. miles Length of Tank Bund 4500 ft. Maximum height 105 ft。 Tank Full:
Storage 38,000 acre feet Spills:
Nature Concrete with four radial gates each
20"×12場”
Length 86ft。 Sluices:
Location L. B. R. B.
Size 2 of 3'x5' 34'x5'
Approximate capital cost Rs. 14 million.
Irrigation Supply ܢ ܕ
A four mile long right bank conveyance channel augments
development in Kirama Oya Scheme with supplemental irrigation to 5000 acres.
The left bank scheme similarly aids development of 4000
acres in Urubokke Oya Scheme and provide irrigation supply to 3000 acres of new development.
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Page 64
18. THE WALAWIE GANGA BASIN
The Walawe Ganga Basin, like that of the Mahaweli, lies in both the south-west and the north-east monsoonal zones. An upper segment of 224 sq. miles receives benefits of the wet zone and the 730 sq. miles in the lower reach receive the dry zone benefits. The mean annual rainfall ranges from 145 inches precipitation in the upper reaches to only 44 inches at Ambalantota, the southern end.
The Walawe Ganga commencing from Adam's Peak is 85 miles long up to Ambalantota and annually conveys about 1.2 million acre feet of water. There are seven major tributaries draining into Walawe Ganga. In all about 1.2 million acre feet of water flows down the ganga in an average year.
Land Use
The present development consists of tea and rubber in the upper basin and 15,000 acres of rice lands in the lower basin. The balance area awaits development.
Water Resources Utilization
The Liyangahatota Anicut situated about 15 miles from the sea, diverts the ganga flow for irrigation supply to the Walawe Right Bank channel and Left Bank Ridiyagama Tank major works schemes, to benefit about 10,000 acres.
Apart from the above there are other major irrigation works and minor irrigation schemes in the basin.
A new reservoir has been constructed across the Hulanda Oya tributary, called-Chandrikawewa to aid development of about 5000 acres of land with rice cultivation.
New Projects
Uda Walawe Reservoir scheme when completed would aid the development of 70,000 acres for agricultural development, approximately as follows:-
Rice cultivation about 34,000 aCS
Sugar cane, cotton and citrus 36,000 s
Samanala Wewa Proposal
A multi-purpose storage reservoir impounding the flow from 132 sq. miles of the main Walawe Ganga has been proposedknown as the Samanala Wewa Reservoir Scheme.
100

The Scheme consists of the main reservoir, a tunnel nearly two miles long, a forebay reservoir power plant and an after bay reservoir at Katupai.
It would supply irrigation for the cultivation of about 23,000 acres with subsidiary food crop and produce 398 million units of electric energy, 120 M. W. capacity.
The resources of the basin would have been well utilized when the proposals envisaged are completed.
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18.1 UGGAL KALTOTA SCHEME
Location
At Kaltota, about 18 miles by road from Balangoda Town. Co-ordinates M121 (0.9X 7.1)
Historical
The area is associated with the name of one Nila, to whom the area was given for development for services rendered by King Gaja Bahu (112-134 A.C.)
Restoration
In 1892 the Right Bank Channel was restored at an initial cost of Rs. 35,271/-. It was improved later and extended subsequently. The Left Bank Channel with an independent anicut was commenced in 1956.
Scheme
Diversion of flow in Walawe Ganga.
Data
Natural Diversion by rock & boulders for R. B. Concrete anicut across Ganga (lower) for L. B.
Catchment Area 152 Sq. miles
Right Bank Scheme (Upper) Length of Structure- Natural Diversion Inlet Sluice and long silt
reach.
Head Sluice 4”×4s
Left Bank Scheme (Lower Site)
Length of Structure 235 ft.
Maximum Height 3 ft.
Planked Bays 2 Nos.
Head Sluice: 2 Openings each 3'x3'-6"
Irrigation Supply
102
Right Bank Channel-about 4 miles long conveys supply to about 500 acres of rice cultivation in Kaltota village. The extension of the channel by another 4 miles benefits additional 500 acres. The new Left Bank Channel system consisting of 1 miles of main channel and 2 miles of distributary channels convey irrigation supply for the development of 650 acres (rice cultivation) as new Colonization Project in Demodera and Meddebedde villages.

18.2 KATUPATH OYA ANICUT
Location
South East of Balangoda, is reached by a steep 4 mile walk from the 5th mile on Balangoda-Kaltota Road.
Co-ordinates M121 (4.4 x 1.6)
Scheme
Diversion of flow in Katupath Oya, a tributary of Walawe Ganga.
Data
Amicut
Catchment area 5. Sq. miles Length of Structure 300 ft. Planked Bays 2 Nos. 5 ft. Wide Height 6 ft. Head Sluice:
Location R. B. Size 3”×1”-6"
Irrigation Supply
104 acres of new colonization development with rice cultivation is benefited by the work.
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Page 66
18.3 DIYAWNNE MAA ELA
Location
About 3 miles South of 11th mile on Balangoda-Kaitota Road in rugged terrain.
Co-ordinates M121 (7.3X2.2)
Historical
In 1908 a small anicut was constructed, which got washed off in 1948. New structure was subsequently erected about half mile down stream. The channel system suffered damage due to floods.
Seheme
Diversion of flow in Diyawini Oya, a tributary of Walawe Ganga.
Data
Amicut
Catchment area | 14 sq miles Length of Structure 80 ft.
10 Nos. Bays 5'x5" Head Sluice:
Location R. B. Size 12”×12”
irrigation Supply
About 200 acres are cultivated in the area.
104

製刪.8
* = ఎrఉణ జట్ల
18.4 UDA WALAWE RESERVOR-SLUICE
18.4 UDA WALAWE RESERVOIR-SPILL

Page 67
18.4 UDA WALAWE SCHEME–R.B. CHANNEL ENTERING CHANDRIKAWEWA
 
 

18.4 UDA WALAWE RESERVOIR
Location
East of the 27th Mile on the Pelmadulla-Ambalantota Road. From Colombo about 100 miles.
Scheme
A new reservoir across the Walawe Ganga, (Vana Nadi of old) formed by a long earthen embankment.
Data
Tank
Catchment area 454 sq miles Length of Tank Bund 2 miles Maximum Height 130 ft.
Tank Fu:
Storage, total 217,800 ac. ft. Usable storage 203,500 ac. ft. Area of water spread 8,400 acres F. S. L. 290 M.S.L.
Spills
Radial Gates 5 Nos. 60.5 ft. X20 ft. Natural spill V− 1250 ft.
Sluices:
R. B. L. B. Capacity 500 Cusecs 1300 Cusecs Power Sluices 1 Ng 2 No
Irrigation By Pass 2 Ng 2 Ng
Power Plant
Two Power Plants installed at each of the sluices, generate 1.8 MW at R.B. and 3.6 MW at L.B., totalling in all 5.4 MW.
(Canals
The Right Bank canal, 26 miles long and 30 ft. wide, conveys 500 cusecs to benefit 25,000 acres.
The Left Bank canal, 25 miles long and 40 ft. wide, conveys 1000 cusecs to benefit 46,000 acres.
Approx. cost Rs. 135 million.
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18.5 HAMBEGAMUWA TANK
Location
In Tanamalwila area, Wellawaya, Uva Province, situated 21 miles West of Tanamalwila and is difficult of access. Co-ordinates P/2 (2.6x7.3)
Historical
An ancient work across the Mau Ara restored in 1890 at an initial cost of Rs. 31,887|- to store about 2,000 acre ft. In 1961 the work was augmented and improved to store
3,400 acre ft.
Data
Tank
Catchment area 20 sq miles Length of Tank bund 2800 ft. Tank full:
Storage 3400 acre ft. Head of water 17ft, Area of water spread 400 acres Spills:
(1) (2) (3) Nature Masonry Masonry Concrete Location L.B. L.B. L.B. Length 24ft。 58 ft. 360ft, Sluices: -
R. B. size 12 Inches dia. L. B. new.
Irrigation Supply
Original channel two miles long benefits 300 acres of rice cultivation. The subsequent augmentation brings under command an additional 375 acres for new development.
Capital Cost
The 1961 improvements works cost Rs. 3 million.
106

18.6 WEL LAWA ANICUT
Location
Near Godakawela; off 21 Mile Stone on the PelmadullaAmbalantota Road.
Co-ordinates P1 (1.1 x 1.8)
Restoration
Present anicut constructed in 1897. Was subsequently improved in 1958 and in 1960.
Scheme
Anicut diversion of flow in Rakwana Ganga.
Data
Anicut
Catchment area 4 sq miles Length of Structure 122ft。 Maximum Height 3ft, Planked Bays 2 Nos. Head Sluice:
Location L. B. Size 4’×2'-6”
Irrigation Supply
A main channel 3 miles long conveys supply to about 250 acres of rice cultivation.
107

Page 69
18.7 AMBAGAHA ELA AMUNA
Location
Near Embilipitiya, by the road side at 3: Mile Stone on the Embilipitiya-Panamure Road. Co-ordinates P16 (5.1 X2.3)
Restoration
The present anicut and inlet channel was constructed in 1891 at a cost of Rs. 30,390. Subsequently improved in 1921 and later in 1959.
Scheme
Diversion of flow in Panamure Ela (which itself is augmented higher by Kitulabokke diversion) to augment supply to Hingura Ara Tank.
Data
Anicut Diversion for augmentation
Catchment Area 27 sq. miles Length of Structure 33ft。 Maximum Height 5ft。 Planked Bays 3 Nos. Head Sluices:
Location L. B. Size 4'-9"x2'-6" Irrigation Supply
Inlet channel to Hingura Ara Tank3 miles long, crosses the Panamure Road near the 2nd mile. The channel flows along a natural stream the Guru Ara, to the tank.
108

8.7 AMBAGAHA ELA AMUNA
18.8T HINGURA ARA TANK D/S OF SLUICE & CHANNEL

Page 70
18.8 HINGURA ARA TANK
18.11 CHANDRIKAWEWA
 
 

18.8 HINGURA ARA TANK
Location
§:Embilipitiya, of34th mile on Pelmadulla-Ambalantota Road.
Co-ordinates P16 (8.2x3.1)
Scheme
Was constructed under the direction of the Central Irrigation Board in about 1891. A beautifully constructed small tank.
Data
Tank
Source of Supply:
Diverted flow from Ambagaha Ela Amuna, through Guru Ara and drainage from self catchment of 4
Sq. miles. Length of Tank Bund 1340ft。 Tank Full:
Storage 340 acre ft. Head of water 18ft。 Area of water spread 38 acres Spills:
Nature Concrete crest wall. Location R.B. end of bund. Length − 70'
Sluices:
Location O.M. 4 ch. Size 12" is hume pipe and tower; downstream well and channel lining. irrigation and Supply
A three mile long main channel convey irrigation supply to over 350 acres of rice cultivation situated on either side of the main road at Embilipitiya.
109

Page 71
18.9 EMBLPTIYA TANK
Location
At Embilipitiya, on the Pelmadulla-Ambalantota Road. Co-ordinates P16 (8.8X2.3)
Restoration
Was restored by P. W. D. in 1891. A new spill was provided
and the Anicut Sluice (Bisokotuwa type) was restored.
Data
Tank
Source of Supply:
Diverted flow from Hulanda Oya Anicut and drainage from self catchment area of 13 sq. miles. Length of Tank Bund 2950 ft.
Tank Full:
Head of water 6.4 feet Spills:
Nature Masonry C.O. Location R.B. Length 30ft。 Sluices:
Location R.B. at 1685 ft. Size 12" |
Irrigation Supply
Benefits 120 acres situated at Embilipitiya. This tank is now supplied by the R. B. Channel of Uda Walawe Scheme.
110

18.10 KITULABOKKE ANICUT
Location
Off Embilipitiya, about 14 miles on the Embilipitiya-Suriyakande Road and a mile walk from there.
Co-ordinates O/10 (13.1 x6.6)
Historica
Presentanicut constructed in 1891, with an initial expenditure of Rs. 12,665/-.
Scheme
An anicut across the Eraporuwa Ganga diverts the Ganga flow into a channel, for trans basin diversion into neighbouring valley to augment flow in Panamure Ela-which is the source of supply to the Kolonne Irrigation work under the Hingura Ara Tank.
Data
Anicut Diversion
Catchment Area 19 sq miles. Length of Structure 98ft。 Maximum Height 5ft。 Planked Bays 3 Nos.
Head Sluice:
Location R.B. Size Two Openings
Irrigation Supply
The trans basin diversion conveyance channel is about three quarter mile long and is cut through a ridge of hills, it was constructed in 1891 at a cost of Rs. 19,335/-.
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Page 72
15. CHANDRIKA WEWA
(Reservoir across Hulanda Oya, a tributary of Walawe Ganga)
Location
Is situated about two miles South of Embilipitiya near the 36th Mile Post on the Pelmadulla-Ambalantota Main Road. Co-ordinates P16 (10.2x0.8)
Project
An entirely new work (there had been no tank at the site before) formed by the erection of an earthen embankment across the Hulanda Oya.
Data Tank
Catchment Area 64 sq miles Length of Tank Bund miles Tank Full: V
Storage 22,400 acre fit. Head of water 27景ft. Area of water spread 1,100 acres Spills:
Location L.B. Flank Nature Channel flow Length v, 1000ft。
Sluices:
Location Right Bank Size 2 Openings each
3'-9x3'-9"
Irrigation Supply
Main channel 7 miles long, with a conveyance at commencement of 146 cusecs, terminates at Metigatwela tank. A
system of 20 Distributary Channels totalling over 30 miles, command an extent of 5300 acres consisting of 250 acres in Halmillaketiya, about 2200 acres in Tunkama, 1100 in Kuttigala and 1700 acres (Tract VI) in Padanangala. The R. B. Channel of Uda Walawe now flows through this tank.
Capital Cost
Rs. 14 Million.
Progress
Water stored in the tank for the first time in 1963.
112

LsìJIN V VLO LVHVAÐNVAIT zi '8||

Page 73
18.12.3 RDIYAGAMA TANK-SLUICE
18.12.3 RIDIYAGAMA TANK
 
 
 
 
 

18.12 WALAWE SCHEME (LOWER BASIN)
Irrigation development in the lower reaches of the Walawe Ganga (Vana Nadi of old) basin consists of the diversion of the Ganga at Liyangahatota by an Anicut, which diverts supply to Left Bank and Right Bank channel systems.
Walawe Left Bank Scheme feeds Ridiyagama and Kadawara Tanks while the Right Bank Scheme feeds Mamadola and Oluwila Tanks for intermediate storage.
Head Works of the Scheme, (Liyangahatota Anicut) WaS COstructed in 1889. The Left Bank Scheme was incorporated in 1924.
HEAD WORKS LIYANGAHATOTA ANICUT
Location
In Hambantota District, is situated mile East of Barawakumbura, a village 11 miles from Embilipitiya towards the South on the P.W.D. road from Pelmadulla to Ambalantota. Co-ordinates P/12 (2.1 x 4.3)
Data
Anicut Diversion
Catchment area 882 sq. miles Length of Structure 240 ft. Maximum Height 18ft。 Four Scour Sluices
Head Sluices: L.B. R.B.
Size 5 ft. x 7 ft. 6 ft. x 3 ft. Head of water 6.35ft 9.5ft。
Irrigation Supply
A total extent of 12,670 acres are irrigated under this Anicut through the Walawe Left Bank and Walawe Right Bank Schemes.
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18.12.1 WALAWE RIGHT BANK SCHEME
MAMLADOLE TANK −
Location
On the 4th Mile Post of Nonagama-Ratnapura Road. Co-ordinates P/17 (3.83 x 8.30)
Scheme
Walawe Right Bank Scheme.
Data
Tank
Source of Supply:-
Drainage from Catchment area 1.20 sq. miles and supply by Walawe R.B. Channel.
Length of Tank Bund 1800 ft. Tank Full:
Storage 300 acre ft.
(approximately) Head of water ... ' 4 ft. Spills:
Nature Masonry Wall Location L. B. Length 38'-two lengths of
19 feet.
Sluices:
Location L.B. Inlet Sluice & R. B. Outlet
- Sluice Size L.B. 7' 0" wide x4' 0" high
R.B. 7' 0" wide x4' 6' high
Irrigation Supply
Walawe Ganga R.B. Main Channel feeds the tank.
114

18.12.2 WALAWE RIGHT BANK SCHEME-OLUWILATANK
Location
Mile North of 139 Mile Post of Tangalla-Hambantota P. W. D. Road.
Co-ordinates P/17 (6.46X5.40)
Scheme
Walawe Right Bank Scheme.
Data
Tank
Source of Supply:
Drainage from Catchment area 0.25 sq. miles and Supply by Walawe Right Bank Channel.
Length of Tank Bund 1935ft, Spills:
Nature Clear over fall, concrete slab
pitching. Location Right Bank Length 30ft,
Sluices:
Location L.B (LowLevel) R.B. (High Level) Size 3' 0" wide 3' 0" wide
5' 0" high 2' 6" high
Irrigation Supply
No. 3 D Channel of Walawe Right Bank Scheme feeds the
tank. The Oluwila L. B. Channel 200' and Oluwila R. B. Channel 1500' irrigate the fields at Oluwila and Tawaluwila.
115

Page 75
18.12.3 WALAWE GANGA LEFT BANK SCHIEMEROYAGAMA TANK
Location
Is situated in Ridiyagama village, the terminus of the 6 mile
long P. W. D. Road running North from Ambalantota Co-ordinates P/12 (5.70x2.03)
Project
This tank which is the main reservoir in the Walawe Ganga L.B. Scheme was commenced in 1923 and completed in 1928.
Data
Tank
Catchment area:
12 sq. miles but is mainly fed by the Walawe Left Bank diversion channel from the 240 ft. long Anicut across Walawe Ganga at Liyangahatota.
Tank Bund: Length 1 miles
Average height 20 ft.
Storage 21,750 ܖ acre ft. Head of water 17ft. Area of water spread 2,200 acres
Spills:
No. 1 No. 2 Location R.B. R.B. Type Natural Natural
n with crest wall
Length 210ft.87ft,
Sluices:
Location ܫ L.B. Size Two Openings of
3' X4'
irrigation
The work irrigates a total extent of 5,700 acres, listed under Walawe Ganga Left Bank Scheme.
16

18.12.4 WALAWE LEFT BANK SCHEME
KADAWERA TANK
Location
3 miles North of 3rd Mile Stone on Ambalantota-Ridiyagama Road.
Co-ordinates P/12 (7.15x 1.72)
Scheme
Walawe Left Bank Scheme.
Data
Tank
Source of Supply:
Drainage from Catchment area 24 sq. miles & Walawe Left Bank Channel.
Length of Tank Bund 100'
Spills:
Nature . Natural Spill Natural Spill Location L.B. R.B. Length 100ft 200ft。
Sluices:
Location At 610 ft. from L.B. end of Bund Size 15" diameter.
Irrigation Supply
Walawe Left Bank Main Channel feeds the tank and Walawe Left Bank Main Channel also directly feeds the fields.
117

Page 76
20. MALALA OYA BASIN
The Malala Oya, which drains an area of 156 sq. miles has its, source near Augunukolapelessa and collects its waters from innumerable clusters of minor abandoned tanks of ancient Ruhuna. Three works of development in the basin are Mahawewa, Mahagalwewa and Badagiriya which are recent restorations for Colonization. Much of the run off from the catchment is very likely lost in percolation en route as the sea outfall of the Oya at Malala Lewaya and the Malala Modera are not impressive in magnitude.
118

20.1 MAHA WEWA
Location
About 10 miles to the West of Tanamalwila on the Hambegamuwa Road.
Co-ordinates P12 (6.7 x 1.9)
Restoration
1956-60.
Scheme
Storage Tank.
Data
Catchment area 5 sq. miles Length of Tank Bund 2200 ft, Tank Full:
Storage 630 acre feet. Head of water 11 ft. Area of water spread 125 acres
Spills:
Nature Channel flow Location R.B. Length 270ft。 Sluices:
Location L.B. R.B. Size 12 ins. 12 ins.
Irrigation Supply
A Left Bank and a Right Bank channel system provide irrigation facilities for 200 acres of rice cultivation.
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Page 77
20.2 MAHAGAL WEWA
Location
About 25 miles North West of Hambantota.
Co-ordinates P/7 (8.75x5.95)
Restoration
Restoration of present work commenced 1953.
Scheme
Impounds the waters of Maha Ara.
Data
Tank
Catchment area 37.0 sq miles Length of Tank Bund 3,900 ft. Tank Full:
Storage 1,446 acre ft. Head of water 10 ft. Area of water spread 240 acres
Spills:
Nature C. O. Spill Location L. B. Length 300' Sluices:
Location R.B. end Size 1”×2”
irrigation Supply
Main Channel 3 miles 2400' long.
The work supplies water for the irrigation of 500 acres for rice cultivation in new colonization development project.
2U

20.3 BADAGRYA TANK
Location
About 12 miles North of Hambantota. Co-ordinates P/13 (2.3x5.7)
Historical
The ruins at Badagiriya are ancient and are reported to include 3rd & 6th century inscriptions. The ruins may be of Badagaldora Vihare built by Kavantissa.
Restoration
Restoration work commenced 1956-57.
Scheme
Impounds the waters of Malala Oya.
Data
Tank
Catchment area w 135 sq. miles Length of Tank Bund 1 miles Tank Full:
Storage 2350 acre ft. Head of water 8ft。 Area of water spread 105 acres Spills:
Nature Concrete on Rock Concrete Structure Location Central R.B. Length 280 ft. and 175 ft. 110 ft. Sluices:
Location L.B.
Size 3 ft. dia.
irrigation Supply
Thc work supplies irrigation for new development of 800 acres of rice cultivation.
Augmentation proposals has a target for bringing under command another 200 acres in addition.
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Page 78
22 KIRINDİ OYA BASIN
The Kirindi Oya basin, commencing from Ella, near Bandarawela elevation 4,000 ft. extends through Wellawaya and Tanamawila to finish up at the southern seaboard at Kirinda near Tissamaharama a total length of 50 miles.
Kirindi Oya is essentially a dry zone river and the flow in it now benefits the irrigation system at Tissamaharama.
Hydrology
The Kirindi Oya has a total watershed area of 455 sq. miles of which about 177 sq. miles are above the 500 ft. elevation, 175 sq. miles lower down with another 103 sq. miles in the plains; average annual rainfall is about 74 inches. Gaugings indicate an average. annual flow of 322,000 acre feet at Ellawela diversion structure.
Land Use
The very upper reaches close to Ella is developed with tea, and lands around and below Wellawaya and Tanamalwila are injungle. the lower reaches close to the coastal plains have been developed for rice cultivation.
Water Resources Utilization-Irrigation
Three major irrigation works at Sudupanawela, Handapanagala and the Kirindi Oya Diversion Works aid the cultivation of about 10,000 acres of paddy lands.
Besides these, there are about 30 minor irrigation schemes.
A storage reservoir is proposed near Lunuganwehera with a storage capacity of 180,000 acre feet for the cultivation of 60,000 acres with rice. Some of this land has to be found from the adjoin
ing basin.
122

22.1. SUDUPANAWELA ANICUT
TLocation ܙ
In Wellawaya, Uva Province. Is reached by the Sudupanawela Agricultural road at Wellawaya.
Co-ordinates M118 (0.2x5.7)
Historical
This anicut was constructed across the Kirindi Oya, in 1891, at an initial cost of Rs. 14,120. It was rebuilt and the scheme improved in 1934 by the Irrigation Department.
Data
Anicut
Stream catchment at Anicut site 40 sq miles Length of Structure 180ft, Height 10 ft. Planked Bays: 4 NoS. i Sluice- L.B. opening 5' x 5 ft.
irrigation Supply
By a left bank main channel over two miles long 356 acres are supplied for rice cultivation.
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22.2 HANDAPANAGALA WEWA
Location
In the Wellawaya area of Uva Province. Is situated about six miles South East of Wellawaya and is reached by a three mile approach road branching off from near 45th Mile Post. on the Wellawaya-Hambantota Main Road.
Co-ordinates M123 (2.8x6.7)
Historical
The area is traditionally associated with the reign of Walagam Bahu (104-88 B.C.) when many works were carried out. The tank is formed by a short bund across the Maha Ara, a tributary of the Kirindi Oya, and abutting at the left bank into Handagalla hill, from which the tank derives its name. Restoration was commenced in 1952 and was completed subsequently; but could not withstand the disastrous flood of December 1957 and was breached. Was however rerestored in 1960, and first supply made for cultivation.
Data
Tank
Catchment area 20 sq miles Length of Tank Bund 3600 ft. Tank Full:
Storage 5000 acre fit. Head of water 19 ft. Area of water spread 450 acres Spills:
Nature Concrete C.O. Location R.B. Length 535 ft. and 100 ft. of rock face.
Sluices:
R.B.-Size 3 ft. dia.
Irrigation Supply
A right bank channel system benefits an extent of 800 acres for development by new colonization.
Capital Cost
124
Rs... 1 million.

22.3 BALAHARUWA TANK
Location
In the Wellawaya area of Uva Province; is situated about seven miles West of the 35th Mile Stone on the WellawayaHambantota Main Road-about 22 miles South West of Wellawaya.
Co-ordinates M122 (8.2 x 1.3)
Restoration
Tank was restored in 1956.
Data
Tank
Catchment area 10 sq miles Length of Tank Bund 4200 ft.
Tank Full:
Storage 630 acre ft. Head of Water 8ft。 Area of water spread 130 астes Spills: (1) (2)
Nature Concrete C.O. Channel Location Right Bank Left Bank Length 70ft。 320ft,
Sluice:
R. B.-18 inches dia.
irrigation Supply
With a main channel over 1 miles long and field channels an extent of 210 acres benefited for rice cultivation, over half of which is new colonization. (Capital Cost
Rs. 3 lakhs.
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22.4 DAMBE WEWA
Location
About 2 miles West of the 43rd mile on HambantotaWellawaya Road, passing Etiliwewa colony.
Co-ordinates M122 (12.4x3.6)
Restoration
Restoration 1960-62
Scheme
Impounds the flow in Dambe Ara and Mimule Ara.
Data
Tank
Catchment area 4.3 sq miles Length of Tank Bund 3550ft。
Tank Full:
Storage 1170 acre ft. Head of water - 13ft。 Area of water spread 175 acres Spills:
Location R.B. Length 200ft。
Sluices:
Location L.B. R.B. Size 15 ins. 15 ins. Irrigation Supply
The work effects irrigation supply to 230 acres of rice cultivation. •
, 26

THE KIRIIND OYA SCHEME
The waters of KirindiCya are utilised for irrigation development by anicut diversion at Elagala near Tissamaharama, and Left and Right Bank Schemes from the anicut. W
The Left Bank Channel takes off about quarter mile above the anicut with a four-bay head sluice with two openings 5 ft. by 4 ft. each, with a conveyance of 440 cusecs and flows down as an inlet channel to Tissawewa. On the way, a feeder channel takes off to supply Deberawewa. Tissawewa supplies water through a plank bay spill to Yodawewa, the last tank in the Kirindi Oya L.B. Channel Scheme. The L.B. Scheme consisting of Deberawewa, Tissawewa and Yodawewa benefits a total extent of 6,224 acres.
Access to the Elagala anicut and Tissawewa inlet channel is gained by the inlet channel road going northwards from Tissawewa Bund passing between Deberawewa and Tissawewa.
The Right Bank Channel taking off from just above the Elagala anicut and controlled by the head sluice cum bridge, on the anicut approach road from the Hambantota-Wellawaya P. W. D. Road, falls into Pannegamuwa Tank. The planked bay spill structure below the bridge on the Hambantota-Wellawaya Road at the 16 mile post delivers supply from Pannegamuwa Tank into the inlet channel to Wirawilawewa; Wirawilawewa is connected to the tank across the road formerly called Yoda-Kandiya Wewa, and now absorbed as Wirawilawewa. The Right Bank Scheme consisting of Pannegamuwawewa and Wirawilawewa benefits a total of 2,241 aCS.
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22.5 ELLAGALA ANICUT
HEAD WORKS OF THE KRNDI OYA SCHEME
This anicut is built across the Kirindi Oya about 7 miles from Tissamaharama and is reached by a two mile road N.E. of the 165th mile post on the Hambantota-Wellawaya Road.
Co-ordinates P18 (8.9X2.6)
The present structure of the anicut was constructed during 187478, at an initial cost of Rs. 101,842.
Damming the flow from 300 sq. miles of catchment area in Kirindi Oya Basin, the anicut is 289 feet long, crest level 103.84. M. S. L. and 17 high from the bed of the river.
The anicut contains a two bay concrete arched scour gate 6 ft. by 4 ft. with sill at 86.34 M. S. L. provided with lifting gate and planking arrangement. A silt ejector 4 ft. bv. 4 ft. is also embodied. at 94.67 M. S. L.
128

22.5 ELLAGALA ANICUT
22.5.1 DEBER AWEWA SPILL

Page 82
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22.5.1 DEBERA WEWA
KRND OYA LEFT BANK SCHEME
Location
Is situated in Tissamaharama about a quarter mile from the Hospital and is approached along the Mutuamma Low Level Channel and Road, turning off near the Tissa Hospital. It can also be reached from the Inlet Channel Road from Tissa Wewa.
Co-ordinates P/13 (10.7x8.6)
Restoration
The present tank was restored in 1889.
Project
Tank
The tank is fed by a 4 mile feeder channel which takes off from the Kirindi Oya Left Bank or Inlet Channel feeding Tissa Tank and is one of the Tissa Tanks.
Data
ll as own Catchment area 2.2 sq. miles, but is mainly fed by Kirindi Oya Diversion waters.
ength of Bund m 700 ft. Average eight 2 ft. | alink Full:
Storage 450 acre ft. Area of water spread 150 acres Spills: .
Clea overfall masonry at left bank Length 62 ft. Spill channel falls into Tissa Tank.
Sluices: w
L.B. High R.B. Low R. B. High Level Level Level (Yatala) Mutiama One opening One opening One opening 2"×1碁' 4'x4' 1 ft. dia. Irrigation Supply
The Channel system benefits an extent of 945 acres of rice
cultivation.
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22.5.2 TSSA WEWWA
KRNDI OYA LEFT BANK SCHEME
Location
The well known tank situated at Tissamaharama in Ruhunu of ancient fame and fed by Kirindi Oya, diversion (Left Bank) effected at the Elagala anicut.
Co-ordinates P/13 (12.2 x 7.6).
Historical
Tissavapi, first large tank in Mahagama,was built by Ilanaga (35-44 A.C). The work has several subsequent references as the area was the seat of the Princes who ruled over Ruhuna.
Restoration
Present tank was restored in 1879 at an initial cost of Rs. 28,572/-. - Recent work (improvements) in 1939.
Later work-Spill raised to level 66.0 in 1949 and to 66.5 in 1955.
Data Tank
Own Catchment 15 sq. miles Is also fed by a 4 mile inlet channel from Elagala Anicut, Kirindi Oya Scheme.
Length of Tank Bund mile (Main Road)
Average height 15ft。
Tank Full:
Storage . 2,900 acre ft. Head of water 14 ft. Area of water spread . 575 acres
Spills:
A 200 ft. masonry structure at L.B. with two planked bays 5' x 7".
Sluices: Location Size
L.B. (low level) 2x3 L.B. (high level) 8"x2' R.B. (high level) 2" dia. Irrigation Supply
The work benefits an extent of 2725 acres for cultivation of rice.
30

22.5.2 TTSSA WEWA
22.5.3. YODE WEWA SPILL

Page 84
ణ్ణిజ్ఞప్తి
22.5.3 YODE WEWA
22.6.5 WIRAWILA TANK
 
 

22.5.3. YODA WEWA KIRINDI OYA LEFT BANK SCHEME
Location
Is the end tank of the Kirindi Oya Left Bank Scheme which comprises of Deberawewa, Tissa & Yodawewa tanks and is situated about 6 miles from Tissamaharama on the TissaKirindi Main Road. Road forms part of the Tank bund.
Co-ordinates P/13 (13.4x5.9)
Historical
Yoda Wewa identified as the ancient Duratissa (the far Tissa Tank) and the adjoining Sitharawila are believed to have been constructed by King Maha Naga in the second century B.C. These were enlarged during King Ilanga (38-44 A.D.) period. In the twelth century A.D., it is recorded to have been restored by King Parakrama Bahu.
Restoration
Tank
Restoration of all the Tissa Tanks were taken up during the administration of Governor, Sir Henry Ward (1855-60) on the recommendation of Civil Engineer, Mr. Harrison and completed in 1902.
Data
Yoda Wewa has its own catchment drainage from 18 sq. miles, but is mainly fed from Kirindi Oya Diversion from Tissa Wewa, crossing the Tissa-Kataragama Road, about
mile from Tissa.
Tank Embankment-Length 3,500 ft. (Main Road) Tank average height 15ft, Tank Full:
Storage 7,900 acre fit. Head of water 12 ft. Area of water spread 1,200 acres Spills: Location L.B. No. 1 L.B. No. 2 Nature Masonry C/O Masonry C/O Length 104ft, 38ft, Sluices:
Location L.B., Central Type Bisokotuwa Masonry Size Two of 2 X 2 3' x 24'
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Irrigation Supply
An extent of 2576 acres is fed by the two channel systems which extend four miles.
Note: The Naga-Gala (Cobra Stone) found at the sluice is tradition
132
ally believed to commemorate the builder-King Maha Naga, such stones, however, are generally associated with the name of the Snake King, Muchalinda, the sacred guardian of the Water,

22.5.4 PANNAGAMUWA WEWA KIRINDI OYA RIGHT BANK SCHEME
Location
Is situated off 16 M.P. on the Hambantota-Wellawaya
Road.
Co-ordinates P/8 (8.7 x 0.5)
Data
Tank
Catchment area 2 sq. miles, but is fed by the Kirindi Oya
Right Bank channel system from Elagala Anicut en route to Wirawila Tank.
Length of Tank Bund mile Average height 7ft, Tank Full:
Storage 1000 acre ft, Head of water 8ft, Area of water spread 275 acres Spills:
L.B. Natural 300 ft.
Spill water flows down to Wirawila Tank.
Sluice:
Location L.B. R.B. Opening 2”×2場” 2 of 8' x 6'
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22.5.5. WIRAWLA TANK
KRNDI OYA RIGHT BANK SCHEMIE
Location
Is 4 miles west of Tissamaharama.
Co-ordinates P/13 (8.6X8.4)
Historical
The stretch of water to the South of the HambantotaWellawaya Road still retains the original historical name of Yoda Kandiya Wewa but the scheme as a whole is merged into Wirawila Tank.
Data
Tank
Catchment area 32 sq. miles, but also receives Kirindi Oya Diversion Supply from the Right Bank Channel fed into Pannagamuwa Tank by planked bay spill below the bridge on the Hambantota-Wellawaya P. W. D. Road.
Length of Tank Bund 1 miles Average Height 17 ft, Tank Full: -
Storage 10,000 acre ft. Head of water 12 ft. Area of water spread 1,400 acres Spills:
Location L.B. No. 1 L.B. No. 2 R.B. Nature Natural Natural Clear over-flow Length 300 ft. 330ft 42 ft. Sluices:
Location Right Bank . Size 4”×3器”
Irrigation Supply
The four mile long channel system irrigates 2,000 acres.
34

26. MENIK GANGA BASIN
The Menik Ganga has its source in the Passara hills, elevation about 4000 ft. and flowing past Buttala and Kataragama reaches the sea at Yala.
The river is about 50 miles long and the watershed area of 497 sq. miles is in the dry zone. Annually about 0.18 m. acre feet reach the sea through the Ganga. Flood period is during the months of November-December.
Most of the basin is in thick virgin jungle, except for some tea near Passara and the rice lands developed under Buttala anicut.
As the Ganga flows through the heart of the Yala sanctuary, and by the strict natural reserve of the Ruhunu National Park, the desirability of programming agricultural development for man is subject to question.
Development proposals in this valley is however advisedly restricted to the restoration of several village tanks, situated between Kataragama and Buttala.
However, if and when it becomes necessary, a storage reservoir can be well sited which would aid the development of 8,000 acres for irrigated agriculture and another 8,000 acres for lift irrigation or highland cultivation.
135هې

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26.1 KONGAHLA WEWA
Location
In Moneragala area of Uva Province. Is situated near Buttala about 3 miles to the north of 142nd mile on the Wellawaya-Pothuvil Main Road. Co-ordinates M118 (9.2 x8.5)
Historical
Is a work that had functioned in the olden days, but was abandoned with over five breaches. Restoration was commenced in 1958.
Data
Tank
Catchment area 1 Sq. miles Length of Tank Bund 1,500 ft. Tank Full: ,
Storage 357 acre fit. Head of water 14ft。 Spills:
Nature Concrete Location Left Bank Length 160ft, Sluices:
Size 2 Nos, each 12" dia.
Irrigation Supply
Work restored to benefit 200 acres for the cultivation of rice.
Augmentation Scheme
The tank has an augmentation project, by the erection of a 33 feet anicut across the Okuruwa Kandura at site M113 (9.2 x 1.5) and the diversion of the Kandura flow by means of a four feet wide inlet channel 1 mile 1600 ft. long. This would give an assured
inflow to fill the tank.
136

26.2 YUDAGANAWA TANK
Location
In the Buttala area of Uva Province; is sited about a mile
and half from Buttala. Co-ordinates M118 (8.0x6.1)
Historical
The tank is said to have been constructed during the reign of King Mahanaga 300 B.C. and the area is traditionally associated with the fight-the “Yuda” between Dutugemunu and his brother. Restoration 1950-52.
Data
Tank
Catchment area Length of Tank Bund
Tank Full:
Storage Head of water Area of water spread
Spills:
Nature
Location Length
Irrigation
1.7 sq. miles 3,000 ft.
1,000 acre ft.
12 ft.
50 acres
Concrete C.O. Left Bank 100 ft.
By means of a mile long main channel, with distributaries and field channels, 252 acres of rice fields are developed for
colonization.
Capital Cost
Rs... 230,000/-
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26.3 BUTTALA ANICUT
Location
In Buttala, Uva Province. The Anicut is reached by a two mile walk along the channel frcm the 141st mile on Wella
waya-Pottuvil Road. Co-ordinates M118 (8.7X6.0)
Historical
Built by the P. W. D. in 1871 across Menik Garga, at an initial cost of Rs. 17.50; in the anicut is incorporated a store which has the following inscription:
“Buttala Ela Built in 1871 by J. A. Araiel and R. D. Ormesby, C.E. Sir Hercules Robinson K. C.M.G. Governor, W. E. Sharpe A. G. A., Dickwella Rate mahatmaya.
Data
Anicut
Stream catchment at site 56 sq. miles Length of Structure 224ft。 Average height 7 ft. Planked bays 3 Nos. Sluice-Two openings 5ft。4署ft。
rrigation Supply
Note
138
The fow in Menik Garga, thus diverted feeds the 44 miles long main channel to supply 1,350 acres of rice fields.
It is customary to release supply frcm this work, to boost up Menik Ganga, on festival occasions for pilgrims needs
at Kataragama.

264 KARAWILA WEWA
Location
In Kataragama area, about 3 miles west by cart track. Co-ordinates PI3 (11.9 x 0.15)
Scheme
Two small tanks-the original Karawila and the neighbouring Mylagama are merged to form one larger work.
Data
Tank
Catchment area 5.0 sq miles Length of Tank Bund - 79 chains
Tank Full:
Storage 290 acre ft. Head of water 7.35 ft. Area of water spread 325 acres
Spills: Nature C.O. spill on R.B., Natural spill on L.B. Location L.B. R.B. Length 300' 225'
Sluices: Location At 27 chs., 37.5 chs., 1 mile 5 chs. Size 3 Nos. 18" di dia. each.
Irrigation Supply
250 acres in Karawilagama village.
139

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31. KUMBUKKAN OYA BASIN
The Kumbukkan Oy a has its scurce in the hills above Moneragala and flowing a lergth of over thirty miles reaches the sea at Kumana.
The basin falls just outside the area of the wet zone and in extent is 476 sq. miles. The Oya is assessed to have a mean annual flow of 586,000 acre feet. But development in the basin has been confined to the upper reaches in and around Moneragala.
It has to be admitted that any attempt at large scale land development for agriculture cannot be undertaken in the lower reaches of this basin, without adversely affecting the seclusiveness of the Yala Sanctuary.
Anyhow, when it is thought prudent to embark on such enterprise, development can best be done by the construction of four reservoirs, the Kumbukkan Oya, Nambane Oya (tributary), Hulandawe Oya and the Alahala Aru reservoirs. These would then provide irrigation supply to about 15,000 acres.
140

31.1 KUMBUKKAN OYA ANICUT
Location
In the Moneragala area, Uva Province. Is situated below Bridge on the 147th mile of the Wellawaya-Pottuvil Main Road, about six miles from Moneragala.
Co-ordinates M118 (12.4X8.2)
The Project
Where the Wellawaya-Pottuvil Main Road crosses the Kumbukkan Oya, the P. W. D. constructed a road bridge with anicut underneath, in 1883. The diversion fed a seven mile long channel. The anicut and channel cost Rs. 188,345. The Irrigation Department improved the work and extended the scheme, making it a comprehensive irrigation development project in 1951.
Data
Anicut
Stream Catchment at site 98 sq miles Length of anicut 200 ft. Average Height 9 ft. Planked bays: Six Nos. each 9 ft X9 ft. Suice: L.B. Two openings 6 ft x 6 ft.
- Irrigation Supply
A left bank scheme, with a ten mile long main channel, four miles of distributary channels and field channels supply 1,600 acres of rice fields about half of which is private and the balance a colonization project in Okkampitiya.
41

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31.2 HULANDA OYA ANICUT
Location
Near Moncragala about a mile south of the 51st mile of Wellawaya-Pottuvil Road. Co-ordinates M114 (2.5x2.8)
Scheme
Anicut diversion of waters of Hulanda Oya, a tributary of Kumbukkan Oya.
Data
Anicut Diversion
Catchment area 34 sq miles Length of Structure 100ft。
with 8 bays each 5 ft. X5 ft.
Head Sluice:
Location L.B. Size - 30" dia.
irrigation Supply
A Left Bank channel carried precariously in the upper reaches on steep terrain, with several drainage crossings convey supply for rice cultivation of about 400 acres of new colonization development.
42

31.3 KUMANA TANK
Location
About 26 miles. south of Panama.
Co-ordinates: P15 (12.1 x 7.9)
Data
Tank
Catchment Area 2.5 sq. mis. Length of Tank Bund 60 chs.
Tank Full
Storage: 375 ac, ft. Head of water 5 ft. Area of water spread 380 acs.
Spills:
Nature Natural Location 12 chs. Length 200ft。
Sluices:
Location 51 chs. Size . 15” dia. Tower type.
irrigation supply
Irrigable area 114 acres for late Mahaor Yala cultivation.
43

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35. WLA OYA BASIN
The Wila Oya is a short stream about twenty miles long in the south-east regions of the island.
The basin is in the dry arid areas south of Pottuvil and is not suitably situated to attract settlement or development.
Annually about 192,000 acre feet of water is computed to be flowing in the river, all of which will be during the north east monsoonal period.
The development of the basin is best done by the erection of a reservoir, more or less at the provincial boundary, which would provide irrigation water supply to about 4,000 acres. .
144

35.1 ETTIMOLE WEWA
Location
In Moneragala Area of Uva Province. Is reached by turning of at the 169th mile on the Wellawaya-Pottuvil Main Road and proceeding 8 miles to Wattegama village and thence another 5 miles along new road. Co-ordinates M114 (10X 1.1)
Historica
The area has important historical references. Ettimole was the capital of "Ruhuna and was the Head Quarters residence of the rulers of Ruhuna. Queen Sugala, the last of them, was defeated in battle by Parakrama Bahu's forces here. The tank Ettimole Wewa-'Uruvela Vapi' as it has been identified, would have been an important land mark. The tank was restored by Parakrama Bahu (1153-1186). Present tank restored in 1962.
Project −
Drainage from 10 sq. miles is stored in Ettimole Wewa and let down the parent stream Wila Oya to be picked up and diverted by an anicut four miles down-stream to benefit a thousand acre left bank colonization project.
Data Tank
Catchment area 9.5 sq. miles Length of Tank Bund 3950ft, Tank Full: .-
Storage 5000 acre ft. Head of water 16 ft. Area of water spread 470 acres Spills:
Nature Concrete (C.O.) Length 130 ft. i Sluice: 30 ins. dia. Pick-up Anicut
Own catchment (excluding Tank) 10 sq miles Length of Anicut 145ft, Planked Bays 3 NOS. Sluice: L.B. 2 Openings, each 3”×2'-6" Irrigation Supply
Supply commences below the pick up anicut with a left bank scheme commanding an extent of 1,000 acres for new colonization development. Capital Cost
Rs. 1.6 million. Progress
Construction commenced 1956.
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35.2 KOTIYAGALA MLAHA WEWA
Location
About 10 miles south of 169th mile on the WellawayaPottuvil Road.
Co-ordinates M120 (0.3 x 6.6)
Restoration
Work 1953-58.
Scheme
Impounds the flow in Uva. Ela.
Data
Tank
Length of Tank Bund mile Tank Full:
Storage 1400 acre ft. Head of water 15ft, Area of water spread 210 acres Spills:
Nature Concrete Concrete Channel Location L.B. 1 L.B. 2 R.B. Length 230ft, 40 ft. 100 ft.
Sluices:
Location R.B. Size 24 inches.
Irrigation Supply
The work irrigates 450 acres of rice fields for new colonization settlement.
146

35.3 PANAMA TANK
Location
This is situated in Panama Pattu D.R.O.'s Division in the Pottuvil Electoral District.
Co-ordinates N116 (4.15x4.85)
Data
Tank - w
Catchmet area Self catchment of 1 sq. mile and supply from Inlet Channel from Willa Oya Anicut Length of Tank Bund 4385 feet Tank Full:
Storage 2170 ac. ft. Head of water - 10ft, Area of water spread 300 acres
Spills: .ܓ No. 1 No. 2 Nature C. O. C. O. Location R. B. R. B. Ilength 116/-9”100ft
Sluices:
Location 40 ch. 33 ft. from L. B. Size 24 ins dia.
irrigation Supply
An R. B. Main Channel 77.30 chains long irrigates a total of 437 acres.
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36. HEDA OYA BASIN
Natural Conditions
Heda Oya is a short stream, which along with the adjacent Karanda Oya, flows eastwards into the eastern sea board at Arugam Bay near Pottuvil. The Oya has its source in the Moneragala hills.
Hydrology
The watershed of Heda Oya is 237 sq. miles; the annual rainfall of the upper catchment is 79 inches of which 51 inches precipitate during the north-east monsoon. December-January are the usual rainy months. The annual yield in the Heda Oya is about 332,000 acre feet.
Land Use
Most of the basin is in jungle; the lower reaches being alluvial plains is suited for agricultural development, provided satisfactory irrigation supply is ensured. Two chief settled areas are around Lahugala and Pottuvil, population of which does not exceed 20,000. About six small irrigation storage projects aid the development of about 3,000 acres of rice lands.
Water Resources Utilization
For utilizing the greater part of the water resources of the basin, a site has been selected for reservoir construction about 15 miles from the sea board. Various preliminary work necessary to collect data has been done.
This reservoir has a catchment area of 161 sq. miles and a yield of 332,000 acre feet, would benefit about 30,000 acres of rice cultivation. The expected cost of the project is Rs. 95 million.
Basin Requirement
Essential requirement of this jungle basin is development.
With the provision of the above project, ensuing development may be visualized as follows:-
Rice Lands 30,000 acres Highland (gardens, etc.) 20,000 , Land for reservoir bed, streams and other
civic uses 10,000
Forest reserves (above the reservoir) etc. 10,000 ,
48

36.1 LAHUGALA TANK
Location
This is situated 10 miles west of Pottuvil.
Co-ordinates: N/15 (13.35X5.15)
Data
Tank
Catchment area 3 sq. mls. and also supply by
channel from Heda Oya. Length of Tank Bund 3700ft,
Tank Full:
Storage 2670 ac. ft. Head of water 9 ft。 Area of water spread 574 acs. Spills:
Nature Masonry Natural
Location L.B. end R.B. end Length 188 ft. 500ft.
Sluice:
Location L.B. end Size 2/9" dia.
Irrigation supply
Length of chls. R.B.-1 ml. 4900 ft. L.B.–1 ml. 1900 ft. Irrigable area 366 acs.
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36.2 RADELLA - TANK
Location:
In Panama area, about 10 mls. South west of Arugam Bay Co-ordinates N111 (3.5 x 0.9)
Historical
Ancient work, which was really composed of two tanks hence probably its name "Erattal Kulam (twin tank), The Northern portion of the tank had apparently functioned separate from the South Western, being separated by a dividing bund.
Has now been restored as a combined large tank known as Radella Tank.
Data
Tank
Catchment area 4: sq. mls. Længth of Tank Bund One mile
Tank Full:
Storage 且650ft, Head of water 11 ft.
Spills:
Nature Rock Location L.B. Length 105 ft and 3 openings
each 4'x3' Sluices:
Location R.B. Size 24” dia.
Irrigation Supply
150
An R. B. channel system conveys supply to new development of 500 acres of rice cultivation.

36.3 NAULLA TANK
flocation:
This tank is situated in Panama Pattu D.R.O's Division in Pottuvil.
Co-ordinates: N/16 (5.40x8.62)
Data
Tank
Catchment area 1.8 sq mls. Length of Bund 625ft,
Tank Full:
Storage 920 ac. ft. Head of water 9 ft. Spills:
Nature Rubble masonry Location 135 ft. from L.B. end Length 41 ft. w
Sluice: −
Location 42 ft. from L.B. end Size 10"
Irrigation supply r
Length of Main Channel 25.80 chs. Irrigable area 255 acs.
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36.4 ROTT TA' KULAMI
Location
This tank is situated 3 miles north of Pottuvil Co-ordinates N111 (6.80 x 6.90)
Data
Tank
Catchment area 15.4 sq. mls. of self catchment and Kunchan Odai Anicut at R.B. of tank diverts water to tank. Length of Tank Bund 5740 feet Tank Full:
Storage 3400 ac. ft. Head of water 12.5 ft. Area of water spread 660 acres Spills:
Nature Natural Length 580 feet ž Sluice:
Location Menthodai Siriya High Level Size 12" dia. 12” dia. 12" dia.
Irrigation Supply
Irrigation development 760 acres.
52

37. KARANDA OYA BASIN
Natural Condition
The Karanda Oya Basin is adjacent and north of the Heda Oya, and is a short stream emptying into the eastern sea board at Arugam Bay near Pottuvil.
Hydrology
The catchment area of Karanda Oya is 167 sq. miles. It is essentially a north-east monsoonal stream which is dry otherwise. Average annual yield from the catchment has been computed at about 132,000 acre feet.
Land Use
Most of the land is alluvial plain and well suited for agricultural development, provided irrigation water supply be available.
The best economic crop to be cultivated has to be decided.
Water Resources Utilization
A site has been selected for the construction of a dam to form a reservoir and some preliminary work has been done in this connection. About 80,000 acre feet of water is available for irrigation supply to about 10 to 12 thousand acres for agricultural development. Approximate cost of project Rs. 25 m.
Basin Requirement
Storage reservoir for irrigation supply is the essential requirement for the development of this arid jungle basin.
153

Page 96
41. RUFUS KULAM ARU BASIN
This is a small basin of 13 sq. miles of catchment area which drains into the sea near Trukkovil. The development of the area is due to the restoration of the Tank between 1920-1930. The ancient name would more aptly have been Thirukkovil Kulam.
S4

41.1 RUFUS KULAM
Location
About 7 miles west of Tirukkovil
Co-ordinates: N/1 (4.9 x 1.8).
Data
Tank
Catchment area 3.8 sq mls. Length of Tank Bund 740 ft.
Tank Full:
Storage 2770 aC, ft. Head of water 16ft。 Area of water spread 350 acs. Spills:
Nature Structure Location R.B. Length 242ft,
Sluices:
Location R.B. Size 2 openings, 2 X 1-6" each
lirrigation Supply
For the cultivation of 1020 acres.
155

Page 97
42. PANNEL OYA BASIN
42.1 PANNALAGAMA RESERVOR
Location
Near the abandoned village Pannalagama.
Co-ordinates: M110 (7.25x8.77)
Scheme:
Storage reservoir restored by the River Valleys Development Board and improved to a larger work. The Pannalagama Reservoir impounds the waters of Pannel Oya.
Data
Catchment area 18 sq miles Length of Tank Bund 1300ft。 Tank Full:
Storage 22,200 ac. ft. Head of water 35ft, Area of water spread 980 acs.
Spills: 3 Nos. 15"X8" Radial Gates-Crest Level 250 M.S.L. Sluices: 48" dia Barrel—Sill Level 215 M.S.L.
Irrigation Supply
The L.B. Channel and distribution system benefits 3600 aCCS.
156

42.2 VAMMYADI TANK
Location
About 15 miles west of Tirrukovil.
Co-ordinates N11 (1.3 x 1.5)
Restoration
Impounds the flow in Potana Oya.
Data
Tank
Catchment area 5.4 sq mls. Length of Tank Bund 1030ft,
Tank Full:
Storage 1 130 ac. ft. Head of water 12 ft. Area of water spread 170 acs. Spills:
No. 1 No. 2 No. 3 Nature structure Structure structure Length 68" 145' 38"
Sluices:
Size 18" dia.
irrigation Supply
Along with Sagamam irrigates 2734 acres.
157

Page 98
42.3 SAGAMAM TANK
Location:
About 6 miles west of Tirukkovil. Co-ordinates N11 (4.9X.3.9)
Historica
Ancient work incorporated in the Gal Oya Scheme.
Restoration
Present work was restored in 1872 at an initial cost of Rs. 105,733. v
Data
Tank
Supply from Ambalam Oya tank and self Catchment aea 5 sq. mls. Length of Tank Bund l ml. Tank Full:
Storage 3620 ac. ft. Head of water 16 ft. Area of water spread 750 acs.
Spills:
Nature Structure CIO Location R.B. Length 295ft,
. Sluices:
Location L.B. R.B. Size 2 " X 1' 24 ins. dia.
irrigation Supply
Supplies irrigation facilities for rice cultivation in 2734 acs.
58

43. AMBALAM OYA BASIN
43.1 AMBALAM OYA TANK
Location
South of G al Oya Scheme above R. B. Main Channel. Co-ordinates MI5 (12.7x6.3)
Historica
New work constructed by Gal Oya Development Board in 1959-61.
Scheme
Impounds flow in Ambalam Oya.
Data
Tank
Catchment area 13 sq mls. Length of Tank Bund 1 mile.
Tank Full:
Storage 35,000 ac. ft. Head of water 25 f,
Spills:
Nature - Crestwall on Rock Location Centre Length 185 ft.
Sluices:
Location RB, Size 3 Nos, each 36 ins. dia.
lrrigation Supply
The work has for target the supply for irrigation development of 600 acres of rice cultivation.
159

Page 99
432 NEETHA KULAM
Location
The tank is about 6 miles S.E. of Irakkamam tank.
Co-ordinates N11 (3.4 x 7.8)
Historical
Previously existing work incorporated in Gal Oya Scheme
Data
Tank
Source of supply Wanagamuwa D. channel, Gal Oya R. B. channel scheme and drainage from. Self Catchment area 1 l Sq. mis. Length of Tank Bund 3300ft,
Tank Full: ܫ
Storage 600 ac. ft.
Head of water 6ft,
Area of water spread 190 acs.
Spills:
Nature channel flow
Location L.B.
Length 350 ft
also planked opening at LB: 3 of 6'X6'.
Sluice: -
Location L.B. R. B.
Size 12 ins. 24 ins.
Irrigation Supply
Along with Illukachchenai, supplies irrigation water for regular rice cultivation in 975 acres.
160

43.3 ILLUKACHCHENAL TANK
Location:
South of Irakkamam tank Co-ordinates K121 (2.9 x 0.4)
Historical:
Previously existing work incorporated in Gal Oya Scheme.
Data
Tank
Source of supply: drainage from catchment area of 7 sq. miles, now augmented by R. B. Main Channel Gal Oya Scheme.
Length of Tank Bund 4300 ft. Tank Full:
Storage I 240 ac. ft. Head of water 10 ft. Area of water spread 220 acs.
Spills:
Nature Structure CIO Location R.B. Length 200 ft. Sluices:
Location L.B. R.B. Size 24 ins. 12 ins.
161

Page 100
44. (GAL OYA BASIN
44.1 GAL OYA ANCUT NEAR BBLE
Location
An existing diversion work, at the head waters of Gal Oya Stream, about 3 miles south of Bibile; it has no connection with the Gal Oya Development Project.
Co-ordinates M13 (7.7X3.1).
Restoration
Restored in 1890, at an initial expenditure of Rs. 32,414
Scheme
Diversion offlow in Gal Oya (across which is the Senanayake Samudra about 25 miles lower).
Data
Anicut
Catchment area 35 sq. miles ' Length of structure 263 ft. Scour Sluices: 2 Nos. each 8' X 7”-6“ Crest level 735.63
Head Sluices:
Location L.B. R.B. Size 2 Openings 2 Openings
4”×7"-6" 4"×7-6"
Irrigation Supply
The left bank channel irrigates over 300 acres and the right bank about 110 acres.
62

31. 1 KUMBUKKAN OYA ANICUT
35.2 KOTIYAGALA MAHA WEWA–SPILL

Page 101
44.2 INTAKE SLUICE SENANAYAKE SAMUDRA
44.2 POWER HOUSE & TAIL CHANNEL
SENANAYAKE SAMUDRA
 
 

GAL OYA SCHEME .
44.2 SENANAYAKE SAMUDRA
Gal Oya Reservoir, at Inginiyagala.
Location
About 54 miles S. W. of Batticaloa. Co-ordinates. J/25 (1.6X 1.0).
Scheme
Storage Reservoir formed by earthen dam across the Gal
Oya, at a narrow gap in the valley by the Inginiyagala hills. Was constructed by Messrs. Morisson & Knudson, Con
tractors, during 1949-52.
Reservoir
Catchment area Earthen Dam
Full Reservoir
Spillway
Length:
Height:
Openings: Sluice:
Power Generation: .
Irrigation Supply
Data
384 sq. miles.
Length 3600 ft.
Height 140 ft.
Top width 30 ft.
Contents-2 million cu. yods.
earth
Storage 770,000 ac. ft.
Head of watcr 10 ft.
Water spread 30 sq. mls.
Site at L. B. about l - mls. from
dam.
Type: Concrete ogee gravity
section with inspection Chamber.
1020 ft. overall.
770 ft. spill length.
60 ft. 6 Nos. of 5" x 5" each. 13 ft. dia pipe.
Penstock 13" dia, 714 ft. long. Surge Tank 48", 112 ft. high.
Generators 4 Nos. each 2500 K.W
Left Bank channel scheme, target 80,000 acres; length of main channel about 32 miles. Right Bank channel scheme, target 40,000 acres; length of main channel about 21 miles. The Reservoir cost Rs. 750 Lakhs (1949) and stores irrigation supply for over 110,000 acres for rice and other cultivation.
163

Page 102
44.3 GAL OYA SCHEME-LEFT BANK MAN CHANNEL
Total length 32 miles.
Main Channel Data
(a) Miles 1 to 8. (Himidurawa) Bed width 50 ft. Depth 7ft. Conveyance 1145 cusecs for 80.000 acs.
(b) Miles 8 to 12 (Uhana)
Bed width 35 ft. Depth 6.7 ft. Conveyance 785 cusecs.
(c) After Navakiri the channel is reduced to about 20 ft.
as only about 25,000 acres (approx) are under command.
The main channel crosses Namal Oya in the 2nd mile and enters Aligalge tank in the 4th mile and thence to Himidurawa tank in the 9th mile.
The Andella Oya tank is reached at the 14th mile, after the Uhana take-off. Navakiri Aru tank is about another 10 miles along the channel.
Paragahakella channel Distributary
Off-take at 5 miles from M. channel Length 3 miles Conveyance 44 cusecs Irrigates 1530 acres
Uhana Branch channel Off-take at 12 miles from
M. channel Length 9 mls. Conveyance 435 cusecs Bed width 25 ft. Irrigates 30,000 acs.
Mandur Distributary Takes of 9 mls. from
Uhana Br. chl. Length 93 mls. Conveyance 259 cusecs Bed width 20 ft. Irrigates 18,000 acres
164

44.4 NAMAL OYA TANK
Location
About 4 miles north of Senanayake Samudra, above L. B. main channel-Gal Oya Scheme.
Co-ordinates J/20 (1.1 x 6.1)
Historical
New work constructed by the Gal Oya Development Board
Scheme ܡ
Impounds the flow in Namal Oya.
Tank
1961-62.
Data
Catchment area Length of Tank Bund Tank Full:
Storage Head of water Area of water spread
Spills:
Nature: Location Length
Sluices:
Location Size
Irrigation Supply
The work provides irrigation c tiltivation.
20 sq. mls. 1 miles.
37,000 acre feet
35 ft. 1600 acs.
Channel Spill R.B. 300ft,
L.B. 48 ins. dia.
supply to 8000 acres of rice
165

Page 103
44.5 GAL OYA SCHEME, LEFT BANK-ALIGALGE TANK
Location
About 4th mile of L. B. main channel of Gal Oya Scheme.
Co-ordinates J/25 (4.6.x2.7)
Historical
New work constructed by Gal Oya Development Board 1950-51.
Scheme
L. B. main channel conveyance tank
Data
Tank
Catchment area 5 sq. mls. Length of Tank Bund 3500ft。
Tank Full:
Storage 2150 acre feet Head of water 8 ft. Area of water spread 270 acres
Spills:
Nature Channel flow with crest wall Location R.B. Length 360 ft.
Sluices:
Location L.B. R.B. River Sluice Size 18 ins. 12 ins. 24 ins.
166

44.6 GAL OYASCHEME, LEFTBANK-HIMDURAWA TANK
Location
On the 9th mile of L.B. main channel Gal Oya Scheme. Co-ordinates J/25 (6.6X 6.5)
New work constructed by Gal Oya Development Board, 1951-52
Scheme
Tank
L. B. main channel conveyance tank.
Data
Catchment area 5 sq. mls. Length of Tank Bund 5000ft。
Tank Full:
Storage 3500 acre feet Head of water 9 ft. Area of water spread 275 acres
Spills:
Nature Rock face CIO Location L.B. Length 200ft。
Sluices:
Location L.B. R.B. Size 1 No. radial gate 24 ins.
15”×8” The work feeds Kondavattavan Tank.
167

Page 104
44.7 GAL OYASCHEME, LEFT BANK-KONDAVATTAVAN
TANK
Location
Below 9th mile of L.B. main channel and adjoining Amparai Tank.
Co-ordinates J/25 (9.1 x 5.8)
Historical
Existing work constructed under the Pattipola Aru Scheme; now incorporated in the Gal Oya Scheme.
Restoration
Present work was restored in 1912.
Data
Tank
Source of supply: inlet channel from Himidurawa tank, Gall Oya Scheme L. B. channel & drainage from Catchment
aCa 18 sq. mls. Length of Tank Bund 4500ft,
Tank Full:
Storage 91.30 acre feet Head of water 19ft。 Area of water spread 880 acres Spills:
Nature channel flow channel flow Location L.B. R.B. Length 350 300
Sluices:
Location Centre Size Two openings, 4'x3'-6"
Inlet channel from Magaha Elaanicut 3 miles long, also completed in 1912.
Irrigation Supply
This work supplies water to Amparai Tank and to Valathipiddy Tank.
168

44.8 GAL OYA SCHEME, LEFT BANK-AMPARAI TANK
Location
At Amparai, Gall Oya Valley.
Co-ordinates J/25 (10.9X 6.4)
Historical
Existing work constructed under the Pattipola Aru Scheme, now incorporated in the Gal Oya Scheme.
Restoration
Present work restored in 1873 at an initial cost of Rs. 32,217 subsequently improved in 1912.
Data
Tank •
Source of supply: inlet channel from Kondavattavan tank, Gal Oya Scheme L. B. channel also
Catchment area 5.4 sq. mls. Length of Tank Bund - mile Tank Full:
Storage 7250 ac. ft. Head of water 13 ft. Area of water spread 900 acres Spills:
Nature Structure Structure Location L.B. R.B. Length 19ft, 320 ft.
Sluices:
Location L.B. Centre Size 10’ x 9’ 2器”×2髪”
169

Page 105
44.9 GAL OYA SCHEME, LEFT BANK-VALATHPDDY TANK
Location
Near the 37th mile, Kalmunai-Inginiyagalla road-about 5 mls. east of Amparai.
Co-ordinates K116 (0.9X0.4)
Historical
Existing work in the Pattipola Aru Scheme, now incorporated in the Gal Oya Scheme.
Restoration
Present work was restored in 1912.
Data
Tank
Source of supply: inlet channel from Kondavattavan tank, Gal Oya Scheme L.B. channel & drainage from
Catchment area 12 Sq. mls. Length of Tank Bund 1 miles
Tank Full:
Storage 2070 acre feet Head of water 10 ft. Area of water spread 380 acres
Spills:
Nature channel flow Location L.B. Centre R.B. Length 100ft,130ft, 170ft,
- Sluices:
Location L.B. R.B. Size 5”×10" 5”×10"
Planked openings
170

44.10 GAL OYASCHEME, LEFT BANK
WEERAGODA. TANK
Location
About 7 miles north of Amparai.
Co-ordinates J/20 (13.x2.5)
Historica
Anicut work incorporated in the Gal Oya Scheme,
Restoration
Present work restored in 1889, with an initial expenditure of Rs. 37,669.
Data
Tank
Source of supply: Uhana Branch channel Gal Oya Scheme, Left Bank channel scheme and drainage from
Catchment area 7 sq. mis. Length of Tank Bund 2120ft。
Tank Full:
Storage 1300 ac. ft. Head of water 12'-9" Area of water spread 260 acs. Spills:
Nature Structure Location L.B. Length 350ft,
Sluices: ズ
Location L.B. Size 20 inches dia.
This work feeds Chadayantalawa tank.
Irrigation Supply
Along with Chadayantalawa tank supplies irrigation to 2217 acres.
17

Page 106
44.11 GAL OYASCHEME, LEFTBANK–CHADAYANTALAWA
TANK
Location
About 9 miles N. E. of Amparai. Co-ordinates K116 (1.4 x 3.3) Historical ancient work incorporated in the Gal Oya Scheme.
Restoration
Restored in 1873 at an initial cost of Rs. 55,926.
Data
Tank
Source of supply: from Veeragoda tank, Uhana Branch channel and drainage from
Catchment area 10 sq mis. Length of Tank Bund 2440 ft.
Tank Full:
Storage 3200 acre. ft. Head of water 15ft。 Area of water spread 600 acs. Spills:
Nature • - Structure Structure Location L.B. 1 L.B. 2 Length 175ft。 400ft。
Słuices:
Location L.B. Size 27 ins.
Irrigation Supply
Supplies irrigation to 2217 acres.
172

GAL OYA SCHEME
44.12 RIGHT BANK CHANNEL
The Right Bank channel commences with bed width of 30 ft. and a mean depth of about 7 feet capable of conveying 750 cusecs and gradually tapers as issues are made, down to 16 ft. bed width and 150 cusecs conveyance in the final section from 20th mile to 21 mile at end of channel.
The channel crosses the Pallang Oya by a syphon in the 4th mil and enters Padagoda Tank soon after.
The Galmadu and Varipattanchennai Distributory channels take off near the 9th mile and the main channel is conveyed by Alahena tank in the 11th mile and by the Malayadi tank at the 13th mile.
173

Page 107
44.13 GAL OYA SCHEME, RIGHT BANK
PALLANG OYA TANK
Location
South of Senanayake Samudra, above R.B. main channel Gall Oya Scheme.
Co-ordinates MI5 (12.8x6.4)
Historical
New work constructed by Gal Oya Development Board 1957-60.
Scheme
Impounds the flow in Pallang Oya.
Data
Tank
Catchment area 36 sq. mls. Length of Tank Bund 2600 ft。
Tank Full:
Storage 93,000 -܀ acre ft. Head of water 55ft。 Area of water spread 2500 acres
Spills:
Nature The tank is expected to absorb the Location entire yield from the catchment. Length J However a natural spill is provided
at the right bank end.
Sluices:
Location R.B. Size 3 Nos each 4” X6"
irrigation Supply
The work effects irrigation supply to 2960 acs. of rice cultivation and 2700 acres of sugar cane development.
174

44.14 GAL OYA SCHEME, RIGHT BANK
EKGAL
Location
ARU TANK
South of Senanayake Samudra, above the R.B. main channel,
Gal Oya Scheme and near the 20th mile on the Siyambalan
duwa-Amparai road.
Co-ordinates M15 (7.6x7.1)
Historical
New work constructed by Gal Oya Development Board
1955-57.
Scheme
Tank
Impounds the flow in Ekgal Aru.
Data
Catchment area Length of Tank Bund
Tank Full:
Storage Head of water Area of water spread
Spills:
Nature Location Length
Sluices:
Location Size
irrigation Supply
The work effects supply for the irrigation development of 420 acres of rice cultivation and 1600 acres of sugar cane
cultivation.
13 sq. mls. 3700ft。
21,500 ac. ft.
18 ft. 1000 acres.
channel
L.B.
340ft。
R.B. 2 Nos. of 4 " X 6"
175

Page 108
44.15 GAL OYA SCHEME, RIGHT BANK
ALAHENA TANK
Location
On the 12th mile of R.B. main channel Gal Oya Scheme and near 26th mile on Siyambalanduwa-Amparai road.
Co-ordinates J/25 (9.1 x 0.5)
Historical
New work constructed by Gal Oya Development Board 1957-59.
Scheme
R. B. main channel conveyance tank.
Data
Tank
Catchment area - 1 l sq. mls. Length of Tank Bund . 4300ft。
Tank Full:
Storage 1770 acre feet. Head of water 6. ft. Area of water spread 250 acs.
Spills:
Nature Structure CIO. Location R.B. Length 200ft。
Sluices:
Location R.B. Size. Radial gates 2 Nos. each 15' x 8”.
Spill, gated sluice and draw off for R.B. main channel are all at one site at R. B. flank.
176

44.16 GAL OYA SCHEME, RIGHT BANKMALAYADI TANK
Location
14th mile of R. B. main channel, Gal Oya Scheme. Co-ordinates J/25 (10.8X0.4)
Historical
New work constructed by Gal Oya Development Board 1959-61.
Scheme
R. B. main channel conveyance tank.
Data
Tank
Catchment Area 5 sq. mls. Length of Tank Bund - 1 mile
Tank Full:
Storage 7300 ac. ft. Area of water spread 580 acres Spills:
Nature Channel flow Location L.B. Length . 200 feet
Sluices:
No sluice provided. The lands below tank bund and above sugar factory are supplied from the R. B. main channel.
177

Page 109
44.17 GAL OYA SCHEME, RIGHT BANK-IRAKHAMAM TANK
Location
About 7 miles S. E. of Amparai.
Co-ordinates K121 (1.4x4.2)
Historical
Anicut work incorporated in Gal Oya Scheme.
Restoration
Present work was restored in 1891.
Data
Tank
Source of supply effected by deviation at Maruthadianicut of Ekgal Aru.
Drainage from Catchment area 7,8 sq mis.
Length of Tank Bund 2650ft。
Tank Full:
Storage 15,700 ac. ft. Head of water 15ft, Area of water spread 2030 acs.
Spills:
2 Nos. 26 ft. and 51 ft. in length
Sluices:
Selindivan Andimadu. Andimadu
Location R.B. L.B. anicut Size 12”×9” 7”×5' 2”×5'
78

45. ANDELLA OYA BASİN
45.1 ANDELLA OYA TANK
Location
On the 14th mile of L. B. main channel, Gal Oya Scheme.
Co-ordinates J/20 (5.4X3.6) -
Historical
New work constructed by the Gal Oya Development Board.
Scheme
L. B. main channel conveyance tank.
Data
Tank
Catchment area 33 sq. mls. Length of Tank Bund 1 mls.
Tank Full:
Storage 2140 ac. ft. Head of water 7 ft.
Spills:
Nature . Structure CIO channel channel Location L.B. 1 L.B. 2 R.B. Length 150ft, 200ft。 300 ft.
Sluices:
Location L.B. L.B. Size 18 ins. 4 pipes each
24 ins.
179

Page 110
45.2 BALAGALLA TANK
Location
The tank is about 2 miles. S. W. of Navakiri tank. Co-ordinates J 120 (3.4X8.7)
Scheme
Tank formed by damming a narrow valley. Impounds waters of Balagalla Ela, a tributary of Navakiri Aru.
Data
Tank
Catchment area 10. I sq. mis.
Tank Full:
Storage 6200 ac. ft. Head of water 25ft。 Area of water spread 500 acres
Spills:
Location R.B. Length 265ft,
Słuices:
Size Opening 36" dia.
80

45.3 NAVAKIRI ARU RESERVOIR. GAL OYA VALLEY
Location
On the 23rd mile of the Gal Oya Scheme main L.B. channel. Co-ordinates J/15 (7.3 x 0.8)
New work constructed in 1950-54.
Restoration
Tank
Impounds waters of Navakiri Aru, source of which is at Friars Hood well known hill of Veddah resident Tissahamy, bounded by Raja Gala hill range.
Data
Source of supply: Gal Oya Scheme main L. B. channel and
drainage from self catchment 70 sq mls. Length of Tank Bund 2 miles.
Tank Full: S.
Storage 42,500 ac. ft. Head of water 19ft, Area of water spread 2700 acres.
Spills:
Nature Structure C/O channel Structure C/O Location L.B. L.B. 2 R.B. Length 250ft。 225ft。 250ft。
Sluices;
Location L.B. Size 2 Nos. each of 4' X 6'
Irrigation Supply
Supplies facilities to 15,000 acres.
18

Page 111
45.4 THUMPANKERN TANK
Location
About 4 miles north of Vellaveli.
Co-ordinates K111 (0.8x7.5)
Historical
Previously existing work incorporated in the Gal Oya Scheme
Data
Tank
Catchment area 1.5 sq. mls. Length of Tank Bund 1970ft。
Tank Full:
Storage 680 ac. ft. Head of water 14'-3" Area of water spread 125 acs.
Spills:
Nature Structure on rock Location L.B. Length 187ft。
Sluices:
Location R.B. Size 20” dia.
Irrigation Supply
Supplies water for the irrigation of 672 acres of rice cultivation.
82

48. - MLANAL, PUDD ARU BASIN
48.1 PULUGANAWI TANK
Location
This tank is situated 6 mls. S.W. of Unichai-Paddirippu E. D.
Co-ordinates J/15 (7.9X 6.5).
Restoration
Present work restored in 1872 at an initial cost of Rs. 56,343.
Data
Tank
Catchment area 10 sq. mls. Length of Tank Bund 2250ft,
Tank Full:
Storage 1875 aC. ft. Head of water 20ft。 Area of water spread 240 acs.
Spills L.B. R.B.
Nature C.O. 90' C.O. structure
natural 10' on rock Location L.B. R.B. Length 200ft。 10f,
Sluices
Location 250' from L.B. end. Size 24荘”×1/6"
Irrigation Supply
Irrigable area-4222 acres: however due to insufficiency of water, only about 2200 acres are regularly cultivated.
183

Page 112
48.2 KADDUKAMUNAL TANK
Location
This tank is situated near Kokkadicholai in Paddiruppu Electoral District -
Co-ordinates: K16 (1.0 x 0.2)
Restoration
Restored in 1872 at an initial cost of Rs. 33,680.
Data
Tank
Catchment area 2.44 sq mls.
& supply from inlet chl. Length of Tank Bund 8044 ft.
Tank Full:
Storage 5026 ac. ft. Head of water 6 ft. Area of water spread 891 acres
Spills
Nature Drowned Length 146ft,
Sluice
Location L.B. R.B. Size 2"1"×8” 2"1"×8"
Irrigation Supply
Main Channel R.B. 1300 ft.
L.B. 100 ft.
Irrigable area 6964, acres (entire Manalpuddi Aru scheme).
184

51 & 52-MAGALAVATTAVAN AND MUN DEN
ARU BASINS
These two adjacent basins in the Eastern Province contain about 800 sq. miles. The area is undeveloped jungle land except at the lower reaches below Unichchai. The Badulla-Batticaloa main road runs for a distance of over 40 miles through the heart of the basin.
Hydrology - - w
The area is situated in the dry Zone and average annual rainfall
is about 70 inches. Annual floods inundate the rice lands in the coastal areas.
Land Use
The upper reaches yet remain in jungle; four storage reservoirs at Unichchai, Rugam, Kitulwewa, Wadamune and a few minor irrigation schemes aid the development of about 30,000 acres of rice cultivation. Bulk of the balance, which is over ten times as much, is not developed.
Water Resources Utilization
For the comprehensive utilization of the water resources of the 800 sq. miles, proposed plan envisages the construction of four storage reservoirs, one each, in the upper reaches of the four streams, Magalavattavan Aru, Rambukkan Oya, Maha Oya and Gallodai Aru. The sites are selected so that yield from 328 sq. miles are being utilized by the four combined reservoirs, amounting to over 643,000 acre feet. Land to be developed is assessed at 60,000 acres in addition to benefiting the 22,000 acres already developed lands below Unnichchai Tank.
Unused water resource potential and land use potential await development.
185

Page 113
51 MAGALAVATTUVAN ARU BASIN
51.1 ADACH CHAL KULAM
Location
5 miles S. E. of Unnichchai Circuit Bungalow. Co-ordinates J/10 (5.65x0.03).
Restoration
Restoration 1950-1952.
Data
Tank
Catchment area 3.25 sq. mls. Length of Tank Bund 2000 ft.
Tank Full:
Storage 510 ac. ft. Head of water 14ft, Area of water spread 65 acres.
Spills: r
Nature C.O. spill Length 150ft、
Irrigation Supply
Benefits 200 acres.
186

51.2 UNNICHCHAI TANK
Location
4 miles approximately east of Badulla-Batticaloa road from 8th mile post. Co-ordinates J/10 (2.60 x 2.50).
Historical
A scheme for restoration of 'Oniche tank was put up in 1892. Proposals to construct the above tank were however framed in 1902 and the work was completed in 1919.
Scheme -
It is not an ancient tank. This was constructed by throwing an embankment across the Magalavattuvan river.
Data Tank
Catchment area 106 sq. mls. Length of Tank Bund 6200 ft. Height 35ft, Tank Full:
Storage 30,500 ac. ft. Head of water 23ft。 Area of water spread 2500 acs. at FSL Spills:
Nature Clear overfall spills. Location - R.B. & L.B. Length R.B. 540' & L.B. 154'
The L.B. spill being extended by 320' with 3 radial gates 20'x10' Sluices:
Location 2 Nos. sluices-one on R.B. other on L.B. Size 4'x3'6" both R.B. & L.B.
Irrigation Supply
The area developed is divided into 3 divisions. 1. L. B. Division. This receives its supply of water through L. B. sluice & the distribution is done through the main chl. 8 M. 2,640 in length. 2. River Division. The L. B. sluice is utilised to supply water to the river division as well. The R. B. sluice constructed to serve the R. B. division eventually is at present utilised to supply water also to the river division. 3. R. B. Division. Area is fed by the R. B. sluice & the chl. has recently been completed to the 13th mile. There is the possibility of extending the chl. to the 20th mile. The area cultivated is 6936 acres, which includes 1700 acres of new cultivation.
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52. MUNDEN ARU BASIN
S2.1 WELGAHAKANDYA TANK
Location
This tank is situated across Thevali Odai Aru just above the confluence of the two main tributaries in the Bintanne PattuCo-ordinates J/14 (9.90 x 7.60)
Restoration
Restoration commenced in 1955.
Data
Tank
Catchment area 5. 10 sq mls. Length of Bund mile
Tank Full:
Storage 1700 ac. ft. Head of water 15ft, Area of water spread 230 acres at FSL. Spill No. 1:
Nature C.O. Location L.B. Length 60 ft. Spill No. 2:
Nature C.O Location R.B. Length 60 ft.
Sluice:
Location - on bund at 13 chs. Size - . One No. 2/24" b pipe.
Irrigation Supply
The development of 566 acres by supply from the work.
88

52.2 RUGAM TANK
Location
mile to the left of Badulla-Batticaloa road at 82 mile post. Co-ordinates J.19 (10.25 x 4.25).
Restoration
Restored in 1868 at an initial cost of Rs. 158,943. Breached in 1891 & repaired by 4th Division Pioneers. Breached in 1957 & repaired in 1958-59.
Scheme ܗܝ
Waters of Mundeni Aru enter the tank. At high flood, the inflow is beyond exact assessment. The tank spills heavily.
Data
'Tank
Catchment area 35 sq. mls. Length of Bund 1 m. 2173 ft. Tank Full
Storage l 6, 120 ac. ft. Head of water 4'10" Area of water spread 2430 acs. Spills:
Nature - v Masonry structure Location At R.B. end Length 1036' 6"
། A natural spill also exists on
the L.B. end. Length 230 feet. Sluices 1
Location At R.B. end. Size 1'-6" x 2'-4" wide.
Irrigation Supply
The storage in Rugam Tank aids rice cultivation in 7814 acres, by a system of channels, drainage streams and pick up anicuts e.g. Sadivakaddu Amicut.
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52.3 KITULWEWA TANK
Location
Tank
This tank is close to Rugam and about 13 mls. S. W. of Chenkaladi. It is situated on the Left Bank of Mundeni
Aru directly opposite Rugam Tank.
Co-ordinates J/9 (9.05x5.75).
Data
Catchment area 11 sq. mls. Length of Bund 7,600 ft. (L.B. 2600 & R.B. 5000). Tank Full:
Storage 4200 ac. ft. Head of water 12ft。 Area of water spread 530 acres Spills: No. 1 No. 2 No. 3
Nature structure structure structure Location L.B. central R.B. Length 200ft, 250 ft. 300 ft. Sluices:
Location At 22 chs and 4.75 chs. on bund
Size - 2 Nos. 24" dia. Tower-sluice.
Irrigation Supply
190
Target for development 800 acres of rice cultivation, in new colonization land.

52.4 KARADIAN ARU TANK
Location
Of the Batticaloa-Badulla road, near 86th mile stone, 10 miles west of Chenkaladi.
Restoration
Restored in 1950-52.
Scheme
Impounds the flow in Karadian Aru.
Data
Tank
Catchment area − 4 sq. mls. Length of Tank Bund å ml.
Tank Full:
Storage 1000 ac. ft. Head of water 8ft。 Area of water spread 225 acres Spills:
Nature Rock Location R.B. Length 310ft。
Sluices:
Location L.B. Size 24" in dia.
Irrigation Supply
Provides irrigation supply for the cultivation of 200 acres in Karadian Aru Farm.
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53 MYANGALLA ELA
53.1 THARAWA KULAM
Location
The tank is situated in the Miyangalla Ela Basin, in the Eravur Korale Pattu. At present the access is to proceed along the tract to Wadamune Tank-up to the 7th mile turn. left and proceed mile.
Co-ordinates J/4 (7.45x7.35).
Historical
Restored in 1962.
Data
Tank
Catchment area 2.66 sq. mls. Length of Tank Bund 3200 ft
Tank Full:
Storage 370 ac. ft. Head of water 7ft, Area of water spread 90 acres Spills:
Nature C.O. spill Location L.B. Length 165 ft.
Sluices:
Location At 27 chs. on bund Size 12" b sluice.
Irrigation Supply
Target for development 200 acres of rice cultivation.
192

54. MADURU OYA BASIN
The Maduru Oya has its source near Bibile and flowing for 86 miles reaches the sea about fifteen miles north of Batticaloa.
The entire region is in the dry zone and the drainage area is 602 square miles in extent. The Oya is estimated to convey a flow of over one million one hundred thousand acre feet, all during the north-east monsoonal period.
The basin area is not well developed and the upper reaches are yet in complete jungle. In the lower reaches rice cultivation are practised mostly under direct rainfall.
Basin Requirement
As these are suitable lands (some of them already under cultivation) for development and water is available in the river, what are wanted very early are storage reservoirs for providing irrigation water supply.
Two reservoirs are proposed, one in the upper regions-the Maduru Oya upper reservoir and another in the lower-the Maduru Oya lower reservoir. These and another across the tributary stream Kuda Oya, would satisfactorily irrigate about 50,000 acres.
The U.N.S.F. Team engaged in the development of the water resources of the Mahaweli Ganga envisage augmentation of the Maduru Oya by a right bank canal from Minipe anicut and with an upper and lower reservoir across the Maduru Oya, provide irrigation water supply to about 101,000 acres of land.
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54.1 ARALAGANWILLA WEWA
Location
Situated about 15 miles south east of Manampitiya.
Co-ordinates J/3 (4.9 x 4.0)
Restoration
Restoration of present tank commenced in 1956. The tank breached for the major floods and was repaired subsequently.
Data
Tank
Catchment area 3 sq miles Length of Tank Bund 4300ft,
Tank Full:
Storage 1560 acre ft. Head of water 12ft。 Area of water spread 250 acres Spills:
Nature Concrete Structure Length 400 ft.
Sluices:
Location L.B. Size 9" x9"
Irrigation Supply
A left bank channel system delivers supply for development of 300 acres of rice cultivation for new colonization develop
ment.
194

54.2 GAL, WEWA
Location
About 5 miles east of Manampitiya.
Co-ordinates G/23 (5.7x4.4)
Scheme
Two village tanks Bora Wewa and Gal Wewa have been
merged, by removal of the dividing bund, to form one large scheme, impounding the waters of Wage Oya, a tributary
of Maduru Oya.
Data
Tank
Catchment area 9 sq miles i Length of Tank Bund 3500 ft.
Tank Full:
Storage 1050 acre ft. Head of water 8.75ft。 Area of water spread 250 acres Spills:
Nature Concrete Rock Face Location L.B. R.B. Length 300 325
Sluices:
Location L.B. R.B.
Size 12" dia. 2 of 12" dia.
Irrigation Supply
The work delivers irrigation supply to 350 acres of new colonization development for rice cultivation.
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54.3 WADAMUNE WEWA
Location
The tank is situated in the Electoral District of Kalkudah and is 3 mls. south as the crow flies from Welikanda.
Co-ordinates G|23 (10.64 x 4.8)
Scheme
Tank restored in 1957-62.
Data
Tank
Catchment area 7.8 sq. mls. Length of Tank Bund 3,200 ft.
Tank Full:
Storage 3660 ac. ft. Head of water 11 ft。 Area of water spread 50 acres Spills:
Nature Concrete Location L.B. R.B.
- at 1 ch. 32 chs. Sluices
Location L.B. R.B. Size 24”dia. 24"dia.
Irrigation Supply
The work aids new development of 400 acres of rice cultivation.
196

S4.4.1 PUNANI ANICUT VAKANERI SCHEME
Location
To the left of the abandoned old Punani Anicut in the diverted section of the Maduru Oya.
Scheme
Anicut diversion
Anicut Data
Length 77' Crest Level 55.75 MSL
Openings Radial Gates 7 Nos. 13' 6" X8' 0”
-- 3 Nos. 20’ 00” X 10' 0"
Irrigation Supply V
L. B. Channel supplements the supply to Vakaneri Tank.
The Distribution system under the R. B. Channel would benefit 1600 acres.
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WAKANER SCBEME
54.4.2 WAKANERI TANK
Location
This tank is situated 10 miles from Oddamavadi town. It is 2 miles from the Batticaloa-Polonnaruwa road.
Co-ordinates G/24 (7.95x5.90.)
Restoration
Present tank restored in 1908. F. S. L. of tank raised by
foot in 1953.
Data
Tank
Source of supply:-Drainage from own catchment area of 4 sq. mls. & mainly diverted supply from Punani anicut, across Maduru Oya. Length of Tank Bund 6800 ft.
Tank Full:
Storage il 1,250 ac. ft. Head of water 17.7ft。 Area of water spread l, 120 acres
Spills:
Nature Masonry spill cum-causeway. Location 14.15 chs. Length 185'8"
Sluices:
Location R.B. L. B. Size 5”×2場” 3”×2塁”
Irrigation Supply
Main channel ll miles Irrigable area R.B. 5580 acres
L.B. 1232 acres
By a long channel system and also by dropping supply & picking up later from the parent stream (river division) the work provides irrigation supply to 6285 acres of rice cultivation.
In addition the work also supplies water for the Government Paper Factory at Valaichchenai.
198

55. PULIYANPOTHA BASIN
55. 1 ANASUDDA "KADDU KUILAM
Location
This tank lies in the village Mankerni, in Eravur Korale Pattu.
This tank is accessible from both the Batticaloa-Trincomalee and Batticaloa-Polonnaruwa roads. The tracks are jeepable in dry weather with difficulty.
Co-ordinates G/19 (9.4 x 1.3).
Restoration
This is an abandoned breached tank selected for restoration.
Data
Tank
Catchment area 5.30 sq. mls. Length of Tank Bund 2,700 ft. Tank Full:
Storage 750 aC. ft. Head of water м 8ft。 Area of water spread 250 acres Spills:
Nature C.O. spill Location R.B. Length 300 ft.
Sluices:
Nature Tower Sluice Size 18"
Tigation Supply
The work has a target of 300 acres of development with rice cultivation,
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56. KRIMECH ODA BASIN
56.1 KIRMACHICH KULAM
Location
The tank is situated in Mankerni village, Eravur Korale Pattu. The tank is reached by proceeding along the Batti
caloa-Trincomalee road and taking the V. C. road on the left at the 28th M.P.
Co-ordinates G/19 (6.90x2.75)
Historical
This is an ancient breached tank having a massive bund of 3100 ft. in length.
Data
Tank
Catchment area 5.85 sq. mls. Length of Bund 3100 ft. Tank Full:
Storage 1260 ac. ft. Head of water 9'6" Area of water spread 275 acres. Spills:
Nature C.O. 220 and rockface 100. Location Left Bank Length 320ft
Sluices:
Location At 28.5 chs. on bund Size 18" Tower sluice.
Irrigation Supply
Target for development 250 acres of rice cultivation.
200

56.2 MARUTHANKERN KULAM
Location
The tank is situated in Eravur Korale Pattu, Batticaloa District. It is about 5 miles. S. W. of Pannichchankerni village. The tank is formed by constructing a bund across the river Pakkilipattu Aru.
Co-ordinates G 119 (5.45x5.30).
Data
Tank
Catchment area 9.30 sq. mls. Length of Tank Bund 5000 ft.
Tank Full:
Storage 2150 ac. ft. Head of water 8ft。 Area of water spread 492 acres Spills:
Nature C.O. spill Location L.B. Length N 250ft。
Sluices:
Location Tower sluice at 25.25chs.
& 48.10 chs. Size 18ᏉᏜ
Irrigation Supply
Target for development 400 acres of rice cultivation.
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59. MAKARACHCHI ARU BASIN
59.1 KADDUMURIPPU KULAM
Location
This tank is situated in Eravur Korale Pattu in the Eastern Division. - -
Co-ordinates G/14 (0.85X3.10)
Data
Tank
Catchment area 25 sq. mls. Length of Bund 5200ft, Tank Full:
Storage 4250 ac. ft. Head of water 11 ft. Area of water spread 750 acres Spills:
Nature C. O. spill Location At 1 m. 2.25 chs. on
bund. Length 800 ft. Sluices:
Location At 5.1 chs. Size 2'6" of Tower sluice
irrigation Supply
Target for development 400 acres of rice cultivation.
202

60. MA HAWEL GANGA BASIN
The Mahaweli Ganga is Ceylon's largest and longest river. It drains an area of 4,034 sq. miles which is nearly one sixth of the area of the island. Its length is 207 miles. It has its sources in the Central highlands and drops nearly 8,000 ft. to flow into the sea at Koddiyar Bay, South of Trincomalee. The Dik Oya which has its source in Marlborough Estate-elevation 4,500 ft. and Dambagastalawa Oya, Agra Oya and Nanu Oya from the Ambawela hills, Horton Plains and Pidurutalagala respectively (all above . 7,000 ft.) are the four streams that form the Ganga. Dambagastalawa Oya flows into Agra Oya and these two streams meet Nanu Oya at Talawakelle to form Kotmale Oya which is one of the largest tributaries of the Mahaweli Ganga. Dik Oya meets Kotmale Oya at Mahavilla and from their confluence the river is called Mahaweli Ganga. The pheripheral length of the watershed boundary is 400 miles and water divides separate this river from the Walawe Ganga, Kirindi Oya, Kelani Ganga, Maha Oya, Deduru Oya, Kala Oya and Maduru Oya.
Land Use and Potential
The Mahaweli Ganga basin consists of distinctive natural regions having characteristic soil types, topography, climate and land use potential. The high lands in the wet zone are well developed with tea, rubber and cocoa on the hill slopes and with paddy in the valleys, but there is very little development in the lower basin. The existing land use pattern' in the basin is given below:-
Land Use Extent Percentage
Acres
l. Urban 7,520 0.3 2. Homestead gardens 172,580 6.7 3. Rubber 32,380 1.3 4. Tea 357,720 3.9 5. Paddy 177,430 6.9 6. Other Permanent Cultivation 84,450 3.3 7. Shifting cultivation 364,700 14.2 8. ForcSt 1,131,190 43.9 9. Grass Land & Scrub 180,760 7.0 10. Unused Land 15,530 0.6 l. Water &Marsh 50,450 1.9
Total 2,574,710 100%
* Taken from the Report on Survey of the Resources of the Mahaweli Ganga
Basin, Part I by the Hunting Survey Corporation Ltd,
203

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The above table shows that 65% of the area of the basin, mostly in the plains, is yet available for development.
Existing major irrigation development schemes in the basin consist of:-
Name of Scheme Extent Benefited 1. Badulu Oya Scheme 2500 acres 2. Sorabora Wewa Scheme 1300 , 3. Damparawa Wewa Scheme 1 100 , 4. Mapakada Wewa 900 , 5. Bathmedilla Scheme 1300 , 6. Alai Scheme 14000 , 7. Minneriya Tank 14325 , 8. Giritalle Scheme 4400 , 9. Parakrama Samudra Scheme 18150 10. Elahera Scheme 4800 11. Kaudulla Scheme 10230 , 12. Minipe Extension Scheme 10460 , 13. Hathtota Amuna 600 , 14. Nalanda Oya Reservoir Diversion Scheme Nil
Paddy is cultivated in all these lands.
Hydrology
The source of the Mahaweli is in the hill country Wet Zone and hence it has two flood peaks and two dry spells. The 820 sq. miles of its catchment area which is in the wet zone experiences heavy rainfall, the highest mean annual fall being 218 inches at Watawala. The balance catchment area of 3,214 sq. miles is in the dry zone where the average annual rainfall varies between 55 to 80 inches.
The average annual run-off of the Mahaweli excluding the 600,000 acre feet diverted annually at Minipe, Elahera and Angamedilla anicuts is 7,900,000 acre feet. The mean annual discharges at some points along the river are:-
at Peradeniya 1,680,000 ac. ft. ,, Gurudeniya 1,935,000 ac. ft. ,, Randenigala -. 2,951,000 ac. ft. , Weragantota 4.206.000 ac. ft. ,, Manampitiya 6.360.000 ac. ft.
The flood cycles in the Mahaweli basin coincide either with the North East or South West Monsoon periods. Major floods were recorded in June 1888, October 1906, December 1913, July 1932, May 1933, May 1940, August 1947 and December 1957. The largest recorded flood experienced in the upper reaches of the river was in August 1947, the flood peak at Peradeniya railway bridge at 2.30 p.m. on the 15th August 1947 was 180,000 cusecs.
204

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Page 123
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Flood peak periods in the lower Mahaweli do not necessarily coincide with that of the upper reaches. In the upper section the river flows mostly through a deep and rocky river channel while the lower portion forms the flood plain. The biggest flood experienced in the flood plain was in December 1957 when the flood peak flow at Manampitiya on the 26th of December was estimated as 514,950 cusecs. The railway embankment at Manampitiya acted as a weir and the flood waters spilled over it for a length of 21,500 ft. Also the Weragantota Rest House which was under 3 ft. of water for the August 1947 floods, was almost completely submerged except for the ridge of its roof.
Water Resources of the Major Tributaries:
The Mahaweli Ganga has numerous tributaries, the main parametres of the larger ones are:-
Name of Tributary Catch- Length Drop in Q
Stream ment 1 12 mils. feet ac.ft. x 105
3TCa
1. Kotmale Oya 226.0 43.3 5500 845 2. Uma Oya 283.0 46.5 5985 520 3. Badulu Oya 152.0 37.5 3394 305 4. Loggal Oya 101.5 28.3 3711 269 5. Heppola Oya 47.6 22.0 4220 70 6. Ulhitiya Oya 170.5 38.5 811 38 7. Hulu Ganga 97.3 8.5 3900 300 8. Hassalak Oya 46.0 13.0 4250 126 9. Heen Ganga 49.7 17.5 5583 218 10. Amban Ganga 573.5 77.1 4100 1165 í 1. Kalu Ganga 107.0 25.0 2775 265 12. Kaudulla Oya 196.0 35.0 517 136
Almost all the major irrigation schemes in the area are fed by the tributary streams. All these schemes are ancient works restored and improved in recent times and reflect the efforts and the skill of the ancient engineers to harness the water resources of the Mahaweli Ganga.
Investigation for Development
Three Teams of engineers and other specialists investigated various aspects of the development that could be undertaken utilising the water resources of the Mahaweli Ganga.
USOM Team
A team from the U.S.O.M. was assigned the task of investigating the most suitable means of augmenting water supplies to the (Dry
205

Page 124
Zone) areas of the North Central Province with the Mahaweliwater. This was done in collaboration with the Irrigation Department, during 1958-1961. Their report, which was published in 1961, outlined a scheme to divert 2500 cusecs of the Mahaweli flow at Primrose in Kandy and convey the discharge in a lined canal to assure double cropping of 97,000 acres of existing paddy land and opening up 155,000 acres of undeveloped land. The plans included four hydro-power stations with installed capacities of 120 MW., 45 MW., 45 MW., and 33 MW. The construction cost of this diversion scheme without land development and infra-structures cost was estimated at Rs. 1203 million.
Hunting Survey Corporation Ltd.
In keeping with an agreement between the Governments of Ceylon and Canada, the Hunting Survey Corporation Ltd., of Canada were awarded in 1955 the task of evaluating the land and water resources of the Island. They worked in collaboration with the Survey Department.
As far as the Mahaweli Ganga basin was concerned, their task was more explicit, for in addition to evaluating the land and water resources, they had to evaluate the land potential for development and to prepare tentative plans for future use and to specify additional investigations required before development could be undertaken. They did their field work in 1958 and published their report (2 volumes) in 1961.
The UNDP-FAO Team
The third team which consisted of experts in irrigation, hydropower, agriculture, sociology, economy etc. from the F. A. O. worked in collaboration with the Irrigation and other government counterparts to prepare a Master Plan for the complete utilization of the water resources of the Mahaweli Ganga for irrigation and hydro-power development and for flood protection. They commenced their investigations in March 1965 and published an ad-hoc report in March 1967 outlining the development potential of the Mahaweli Ganga. In the next stage of their investigations they studied the first priority structures and areas in more detail and finalised the main parameters of the Master Plan.
Their investigations showed, that it would be possible to supply 5,800,000 acre feet of water, from the proposed and existing reservoirs on the Mahaweli Ganga and in the N.C.P. for the irrigation of 9,000,000 acres. The extents to be benefited in the Mahaweli and Maduru Oya basins is estimated as 473,000 acres while the balance 427,000 acres will be in the North Central Province. Proposals envisage an assured water supply to 246,000 acres of already irrigated lands for rotational cropping and opening up 654,000 acres of uncultivated lands for irrigated agriculture. Based on the soil types,
206

diversified agricultural cultivation has been proposed making the project economic and also catering to the food and other demands of the country. In addition to the agricultural benefits, the combined use of the reservoir and canal drops permit development of 2611 K.W. H. of electrical energy annually, with an installed capacity of 507 M.W.
The estimated cost of the project for providing irrigation, drainage . and flood protection facilities, land development and settlement and power production is Rs. 5,583 million. This includes the cost of land clearing and levelling for water delivery to the farmers fields. The foreign exchange component of the expenditure is estimated at 38%. The total capital cost of the project including power transmission lines, overhead expenditure etc. is estimated at Rs. 6,700 million. It is estimated that the annual benefits from agricultural and power production when the scheme has been fully develop
ed will be Rs. 1,320 million and Rs. 114 million respectively.
In view of the vast financial implication, the project has been planned to be implemented in 3 phases over a period of 20 years. The first phase has again been sub-divided into three steps. The estimated cost of the first phase is Rs. 1549.9 million while the first step is estimated to cost Rs. 575.7 million. The target period set for completion of the first step is 1972.
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60.1 AMB EWELA RESERVOR
Location
Near Ambewela Railway Station. Co-ordinates M111 (5.8x4.3).
Scheme
Flow in Dambagastalawa Oya to be impounded near Ambewela and supply diverted across the ridge to the neighbouring Palugama and Welimada valley by a link channel leading to a 450 ft. tunnel underneath the railway line adjoining
Tank
the railway station.
Data
Catchement area Length of Tank Bund
Tank Full:
Storage Head of water Area of water spread
Spills:
Nature Location Length
Sluices:
1. Location
Size Sill Level of Sluice
2. Location
Size Sill Level of Sluice
Irrigation Supply
The work has for target aiding vegetable and other cultivation practised in the Palugama and Welimada valley, an extent of
208
about 1000 acres.
4,000 ac. ft. 62 ft. 150 acres F. S. L. (5992.5)
Structure (C.O.) L.B. 40 ft.
L.B. (in spillway) for discharging 10 cusecs into parent stream. 24” dia.
5930 M.S.L. R.B. (for trans-basin discharge through tunnel).
24” dia.
5960 M.S.L.

60.1 AMBEWELA RESERVOIR TUNNEL INTAKE

Page 126
፰፻፭
60.6 UDUGODA BANDARA EL
 

602 KANDE ELA TANK
Location
In Nuwara Eliya District; is sited on the Blackpool-Amba
- wela main road, about 8 miles from N’Eliya.
The Project
Tank
A tank was constructed in 1947 by damming the narrow Kande Ela Valley: the flow in the ela, thus controlled and regulated, is picked up lower down and conveyed by channel and natural stream ravine to Palugama, for benefiting rice and vegetable cultivation.
Kande Bla Tank: Catchment area i sq. mile. Tank Bund (Road) 460 ft.
Tank full:
Storage 1760 ac. ft. Head of water 27 ft. Area of water spread 110 acres Spill:
Circular “Morning Glory” RCC spill, 3" dia. Crest Elevation: 6170.9 M.S.L. Sluice Size: 14” dia.
Anicut-M/11 (7.1 X6.1)
Natural rock diversion about 3 miles below the tank. Conveyance channel 6 miles long passes through Glenorchy and Ambewela Tea Estates skirting Welimada-NEliya road at 60th mile and afterwards to Edanpolakotha village; it bifurcates (L. B.) to Gawarammera and (R. B.) drops by 700' ravine to Palugama and joins up with Alut Ela Scheme. Benefits 410 acres of rice cultivation and 700 acres of vegetable cultivation.
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60.3 WELKADA ELA
Location - . .
From Talawakelle to Madakumbura Tea Estate Factory and thence to site. Co-ordinates L110 (9.5 x 2.3)
Constructed in 1960.
Scheme
Diversion of flow in Welikada Ela, a tributary of Kotmale Oya, to benefit paddy cultivation in Dunuhadeniya and Medakumbura villages.
Data
Anicut
Catchment area | sq mile Length of Structure 15ft。 Planked Openings 2 Nos 4"x2" | Silt reach 26 ft. long Pick up anicut across Kande Ela at 1 mile 1 1 chains Length of Structure 12ft。 Height li ft. Planked bays 2 Head Sluice 3' x '-6" Silt reach 38 ft. long
irrigation Supply
A two mile channel through tea plantation leads to a ravine which flows down to cultivated area in extent 260 acres.
210

60.4 ATA BAGE OYA ANICUT (UPPER)
Location
Off Panwilatenna, a village near 23rd mile on the KandyGampola-Galaha road.
Co-ordinates L15 (7.7x5.4)
Scheme
Diversion of flow in Atabage Oya (upper reaches). Improved in 1953-54.
Data
Anicut
Catchment area w - 12 sq. miles Length of Structure 126 ft. With two openings 5'x3' and 3'x3'
Head Sluice:
Location L.B. Size 3' x 1. irrigation Supply
A left bank channel system over 1 miles long conveys supply for the development of 140 acres of rice cultivation.
ATA BAGE OYA ANICUT (LOWER) L15 (7.5x5.2)
Location м.
This is in Atabage Udagama, and is about half mile downstream of the Atabage Oya (upper) anicut. Improved in
1949.
Data
Anicut
Catchment area 12 Sq. miles Length of Diversion Walls 20 ft. and 28 ft. Head Sluice: 2 x 1' L.B.
2' X 1 ' R.B. L.B. Channel- mile (Bulane Channel) R. B. Channel-1 miles (Maharawela Raja Ela) Rice area benefited-172 acres.
21

Page 128
60.5 GAMPOLAWELA RAJA ELA
Location
Between Gampola and Nawalapitiya. Turn westwards near 19 M.P. on Gampola-Nawalapitiya road and proceed 3 miles.
Co-ordinates L15 (1.9X 2.0)
Restoration
Anicut work restored in 1938.
Scheme
Diversion of flow in perennial stream—Ulapane Oya.
Data
Anicut Diversion
Catchment area 6 sq. miles Length of Structure 27 ft. upper stretch 57 ft. lower stretch Maximum height 3ft。 Head Sluice Two openings each
3' x 2"
irrigation Supply
A long channel over 8 miles in length irrigates 435 acres, situated on either side of the main road to Nawalapitiya.
22

606 UDUGODA BANDARA ELA ANCUT
Location
Near Wattegama; 1 miles north west of lith mile on Kandy-Madulkele road.
Co-ordinates 120 (12.2 X 2.2)
Scheme
Diversion of Maha Oya. Constructed in 1938.
Anicut Diversion
Catchment area i.l sq. mile
Length of Structure 23 ft.
Maximum height 5ft,
Head Sluice 3'-6" X 1 '-6" Irrigation Supply
L. B. channel 4 miles long with several water falls effects supply to 285 acres of rice cultivation.
213

Page 129
60.7 MURAPOLA ELA ANCUT
Location
Near Hanguranketa. Turn westwards near 13th mile on Kandy-Hanguranketa road; proceed one mile to channel at 8th mile.
Co-ordinates MII (0.8 x 6.0)
Scheme
Diversion of flow in Gurugal Oya and in Kuda Oya, constructed in 1948-51.
Data
Anicut Diversion (3 anicuts)
Catchment area | 1.6 sq. miles
Gurugal Oya Anicut
Length of Structure 76."
Kuda Oya First Anicut v
Length of Structure 90'
Kuda Oya Second Anicut
Length of Structure 104
Head Sluice 3'-6" x2'-8"
Irrigation Supply
A long channel system-over ten miles in length collects the flow from the three anicuts and conveys to rice fields and other development in Bopitiya and Marassana, totalling over 2000 acres. Further augmentation works are envisaged. The work cost Rs. 18 lakhs (1948).
24

60.7 MURAPOLA ELA

Page 130
60.9 MA-EA DVERSON
60.9 MA-ELA CHANNEL KANDURA CROSSING
 
 

608 WEERAPITIYAMAHA ELA
Location
Near Rangalla; from Teldeniya proceed towards Rangalla and then north for 3 miles from near the 21st mile.
Co-ordinates J/16 (4.6x3.0).
Restoration
Restored in 1897.
Scheme
Diversion of flow in Kota Ganga.
Data
Anicut
Catchment area 3 Sq. miles Length of Structure 25ft, Maximum height 3ft, Size 5”×2”
Irrigation Supply
A left bank channel system over 3 miles in length conveys irrigation supply to 170 acres of rice fields.
215.

Page 131
60.9 MIA-ELA AN CUT
Location
Near Hewaheta; about two miles south of the 31 M. P. on the Kandy-Galaha-Rikilligaskada road.
Co-ordinates M11 (2.6X2.3)
Scheme
Restored in 1900, for part diversion of flow in Mul Oya.
Data
Anicut Diversion
Catchment area 5 sq. miles Natural diversion by rock Head Sluice 3 / X -9"
Irrigation Supply
An eight mile long channel, crossing and re-crossing the main road at five places and finally reaching Hanguranketa area after supplying Willwala areas etc. and Walugam Wewa, benefits in all an extent of 1360 aores for rice cultivation and other crops.
Walugam Wewa, M/1 (4.6 X 5.6)
Source of Supply-Ma-Ela Irrigation Channel
Length of Tank Bund 424ft。 Two Masonry Spills L.B. 15 ft. R.B. 25 ft.
Serves as intermediate storage for 535 acres.
216

60.10 KTULPE ELA
Location
About 5 miles from Rikillagaskada, along Hewaheta and Ekiriya road.
Co-ordinates M11 (1.7x5.8)
Historica
The Unantenna area is Ruantenna of old which was the name during the days of King Kirtisiri Rajasinghe. On the R. B. of the Head Works is “Dolugalakanda' reputed to have harboured Prince Pandukhabaya during the period of his misfortunes. On the L. B. is “Malhethgoda' where he met his uncles in battle.
Restoration v
Restored in 1935 and subsequently improved in 1950 and 1955. -
Scheme
Anicut diversion of Mal Oya flow into Unantenna channel etc.
Data
Amicut
Catchment area 13 sq. miles Length of Structure 170ft。 Maximum height 3 ft. Planked bays 3 Nos. Silt reach 37 ft. long with scour
bay. . Head Sluice:
Location R.B. Size 6”×3”
Irrigation Supply
3 miles long channel system conveys irrigation supply to 400 acres of rice cultivation.
217

Page 132
60.11. WADUWAWELA ELA
Location
Is across Belihiul Oya, under the bridge near culvert No. 27/13 .
on Padiyapelella-Ellamulle road which takes off from 28 mile on the Kandy-Padiyapelella-Maturata road.
Co-ordinates MII (5.2x0.7)
Scheme
The present masonry anicut was restored in 1887, together with a four mile long channel, but was abandoned after the 1915 earth slip, Was reconstructed and the scheme put into working order in 1951
Data
Anicut Diversion
Catchment area 21 sq. miles of up
land area Length of Structure 70 ft. Maximum height, 4 ft. Head Sluice 5'-6" x 3'-6"
Irrigation Supply
Four mile long channel skirting steep hill slopes is intercepted by streams; pick up anicuts across Ampiti Oya and Ukutu Oya, both in the first mile of channel augment conveyance and altogether 328 acres are irrigated for rice cultivation.
218

60.12 LEMASURYAGAMA ANICUT
Location
About 8 miles from Padiyapelella; at Lemasuriyagama. Turn northwards near 31st mile on the Kandy-MaturataRagalla road and go down about two miles.
Scheme
Diversion of flow in Belihiul Oya, for the development of a settlement sponsored by Mr. Le-Mercier, Govt. Agent, Kandy. Constructed in 1893.
The anicut, turned over as an entire block, during the floods in 1923 and was rebuilt subsequently.
Data
Anicut Diversion
Catchment 44 sq miles Length of Structure 50ft. Maximum height 4 ft. Head Sluice 2'-3"x4"
irrigation Supply
An L. B. channel system in steep land, about 3 miles long, irrigates 264 acres.
219

Page 133
60.13 DKILYAD DE ELA
Location
In Lewellegolla village in Walapane, and is reached by a 3. mile walk from Wattumulla, at 38th mile on Kandy-Ragalla road.
Co-ordinates M11 (11.4X2.3)
Restoration
Restoration commenced in 1957.
Scheme
Diversion of flow in Aran Oya.
Data
Anicut V
Catchment area 2 Sq. miles Length of Structure 27ft。 Planked bays 2 NoS. 4' X3" Silt reach 65 ft. long Inlet Sluice:
Size 2'-6”×2” Silt escape 4'x3'-9"
Head Sluice:
Size 2'-6”×3'-9” Low level silt escape 2”×6"
Irrigation Supply
Two mile long channel system conveys supply for the development of 250 acres with rice cultivation.
220

60. 14 MNPE YODE ELA
An anicut diversion scheme across the Mahaweli Ganga.
Location
The Head Works is reached by travelling 46 miles from Kandy to Weragantota and then 12 miles along agricultural road, passing Morayaya. The channel (Yode Ela) is crossed over at Hassalaka, near Weragantota-on the opposite bank of the Mahaweli Ganga is Aluthnuwara (Mahiyangana). Co-ordinates M12 (3.9x8.8)
Early History
Head works identified as the '"Manimekkala Dam across the Mahaweli Ganga, constructed by Aggabodhi I (575-608 A.C.) when 17 miles of the Minipe Canal identified as "Pabbatana Canal'', was also constructed. Later, the Pabbatana Canal was extended to a length of 47 miles during the reign of King Sena II (853-887 A. C.).
Restoration
The scheme was restored in 1941, as a colonization project when anicut Head Works and 17 miles of Minipe Channel were constructed. A.
Large scale extension of the scheme was however commenced in 1949, when the anicut was raised and Head Works improved and the channel widened and regraded, to be extended over thirty miles. The new Minipe Yode Ela will be augmented by inflow from Hassalaka Oya and Heen Ganga and other
Streams.
Data
Diversion Anicut across Malaweli Ganga Catchment area of Ganga 1218 sq miles Length of Structure 735ft, Maximum height ... " 14ft。 Planked bays 98 Nos. Head Sluice (L. B.) 11”-6”×3"
Irrigation Supply
The target is irrigation supply and development of 21,500 acres of rice cultivation, for two seasons regularly, Extension work is estimated to cost 550 lakhs (1960).
22

Page 134
60.15 KEENAWELA LA
Location
In Uda Pussellawa area; from Rupaha school (RupahaNildandahena-Watumulla road) down hill walk of 1. miles to reach head works.
Co-ordinates M/7 (0.2 x 6.6)
Scheme
Anicut across Madullu Oya, constructed several years ago, first reconditioned in 1908 and later considerably improved
in 1963.
Data
Anicut Diversion
Catchment area 27 sq. miles Length of Structure 60 ft. Maximum height 6 ft. Planked bays 3 Nos. Head Sluice 3'-6" x2'-6"
irrigation Supply
Four mile long channel on sloping face of hill country conveys supply to 300 acres for development with rice cultivation, in Madulla village. Improvement works cost 2.2 lakhs in 1963.
222

أ. الالم
60.14 BRIDGE CUM SPILL OVER HASALAK OYA MINIPE SCHEMIE
60.14 BRIDGE CUM SPILL OVER HASALAK OYA (DIS VIEW)
MINIPE SCHEME

Page 135
60. 19 DIVERSION OF WELA OYA BATH MEDILLA SCHEME STAGE II
60.19 DIVERSION OF UMA OYA BATHMEDILLA SCHEME STAGE I
 
 

60.16 UMA ELA
Location
Head works reached by stiff 3 miles walk down hill from Hakgala near N'Eliya. Co-ordinates M111 (8.7 x 8.5)
Present work constructed in 1900 by the beneficiaries and later improved by the Government.
v
Scheme
Diversion of flow in Uma Oya (upper-reaches).
Data
Anicut
Catchment area 16 sq. mls. Length of Structure 76 ft. Scour Sluice 4'4'x4' Head Sluice:
Location L.B. Size 6'x4'
Irrigation Supply
A ten mile long winding channel, which almost reaches Welimada area, supplies water to 1000 acres of rice cultivation in steep terrain.
223

Page 136
60.17 MAHA ELYA ANCUT
Location
In the Boralanda Ohiya area of Uva Province. Is reached by the Welimada-Ohiya road, 8 miles drive to Rahangalla. Farm and 3 miles walk along the channel.
Co-ordinates M/16 (10.7 x 8.4).
The Project
Originally a stick and boulder amuna diverted the flow of Mahatotilla Oya to Hinnarangola Ela, along a 3 miles long. channel benefiting rice and other cultivation in Hinnarangolla Village. Subsequently permanent anicut structure was constructed called the Maha Eliya Anicut, and the main channel was widened, regraded and extended.
Data
Anicut
Stream Catchment at site 6. Sq. mis. Length of Anicut 56ft, Average height 4 ft. Planked bays-two 4'x4' each Sluice-L. B. size 4碁”×2”
Irrigation
The 7 mile long left bank main channel conveying 25 cusecs. at commencement drops supply to the Hinnarangolla private lands over 380 acres at the Kandura crossings and outlets for rice and vegetable cultivation. Potatoes are cultivated at the Rahangalla Farm. The last 4 miles of channel benefits over 500 acres for new development with suitable crops.
Capital Cost
224
Rs. 3 lakhs.

60. 18 MAHATOTLLA OYA ANICUT
Location
In Bandarawela area of Uva Province. Is situated near Bandarawela and is reached by a short walk from culvert No. 6/8 on the Bandarawela-Welimada Main Road.
Co-ordinates M112 (2.6x3.8).
The Project
An anicut founded on solid rock just above a 30 ft. fall of thc Mahatotilla Oya, diverts flow from 60 sq. miles, to a right bank channel commanding 700 acres for development. The left bank is too steep for agricultural enterprise. Construction commenced in l96 li .
Data Amicut
Stream Catchment at site 60 sq mls. Length of anicut structure 100 ft. Planked bays-two 4墨/×4′ rrigation
A right bank main channel 44 ft. wide at commencement and 6 mileslong, extending up to the 7 M. S. on the WelimadaBadulla Road, will command new development.
Capital Cost
Rs. one million.
225

Page 137
60.19 BATHIMEDLA EL LA
Scheme
The flow in Uma Oya is diverted by an anicut in Talpitigala Rubber Estate and carried in a conveyance channel (usually designated Stage 1), across the ridge into a natural stream, which flows into Wela Oya valley.
The Wela Oya is dammed at Kivulegedera and left and right bank channel irrigation schemes constructed as Stage 2.
Further, about 3 miles below, another pick up anicut across the same Wela Oya diverts the accumulating drainage flow by a new mid channel to irrigate the lands in the tail end of
Stage 11. Stage 1-Diversion of Uma Ova
Anicut
Location Talpitigala Estate
Co-ordinates M12 (3.2 x 0.3).
Length of Structure 382 ft.
Crest level 1000.96 R.L.
Sluice Two of 4'6" x 4'3"
Conveyance Channel Conveyance from anicut to ridge.
Bed width 7ft。
Conveyance 65 cusecs.
Length 5 miles.
Stage 11-Diversion of Wela Oya
Anicut -
Location At Kivulegedera about 30 miles
north of Badulla.
Co-ordinates M12 (7.5 x 4.6).
Length of Structure 82 ft.
Crest level 643 R.L.
Sluice 1 L.B. 4'3" x 3'
11 R.B. 2'9" X2'6".
Irrigation Supply
L.B. Channel system 6 miles long irrigates 1200 acres. R.B. Channel irrigates 200 acres.
Mid Channel
Amicut
Location At Kivulegedera about 25 miles
from Badulla. Co-ordinates Mi2 (5.8 x 6.1). Irrigation Supply
This work augments supply to about 250 acres of lands in the tail end of Stage 2, by a channel system 4 miles long.
226

60.20 BATATU HENA ANICUT
Location
About 8 miles west of Kandeketiya and situated along the Mahaweli Ganga, opposite to Minipe.
Co-ordinates MI2 (2.2 x 7.4).
Construction
Constructed 1962-1963.
Scheme
Diversion of flow in Uma Oya in the lower reaches, about mile above its confluence with the Mahaweli Ganga.
Data
Amicut
Catchment area - 168 sq mis. Length of Structure 635 ft. on rock
Openings 13 Nos. each 4" wide.
Head Sluice:
Location R.B. Size 4'-6”×2”
irrigation Supply
A 3 mile long channel conveys supply to 100 acres of new colonization area situated by the banks of Mahaweli Ganga.
227

Page 138
60,21 BADULUPITYA ELA
Location
About a mile S. W. of Badulla. Co-ordinates M17 (8.9 x 2.6).
Restoration
Restored in 1897.
Scheme
Diversion of flow in Badulu Oya, about mile below the Alut Oya Anicut.
Data
Tank
Catchment area 46 sq. mls. Length of Structure 163 ft. Crest level 2205.5 M.S.L. Scour Sluices two 4'x4' each
Head Sluice:
Location L.B.
Size 5”×2”
Irrigation Supply
Left bank channel system over 2 miles long aids the development of rice cultivation in 200 acres, in Badulla town. The channel runs past the Hospital and the Irrigation Department Subdivisional Office.
228

60.22 TALDENA ELA
Location
Head works below 6th mile on Badulla-Migahakiwula Road. Co-ordinates M7 (9.9X7.2).
Restoration
Restored in 1888 at an initial cost of Rs. 21,873.
Scheme
Diversion of flow in Badulu Oya.
Data
Anicut
Catchment area 92 sq. mls, Length of Structure 158ft, Scour Sluice 8' x 4'-6" Head Sluice:
Location . L.B. Size - 4”×3"
irrigation Supply
Long channel skirting the road all along the 7 mile length supplies irrigation facilities to 200 acres of rice fields.
229

Page 139
60.23 BADULU OYA ANICUT
Location
In the Kiullegedera area of Badulla District. The Anicut is sited across Badulu Oya, in the lower section about 10
mile before its confluence with the Mahaweli Ganga and is
reached from Kandeketiya, 18 miles from Badulla.
Co-ordinates M12 (7.0x4.3).
The Project
Drainage from over 100 sq. miles is diverted by an anicut to a right bank colonization scheme extending to the banks of Mahaweli Ganga, benefiting over 2000 acres for new develop
ment.
Anicut
Stream Catchment at site 114 sq mls. Length of anicut 217 ft.
Crest level 573.0 Average height 5ft。 Planked bay: one, 5' x 6'
Sluice: V
Two openings 4' x 4' each.
Irrigation
Main right bank channel over eight miles long, designed to . convey 82 cusecs at commencement and four distributary channels totalling 9 miles, with necessary field channels to command 2513 acres for development with rice cultivation.
Capital Cost
Rs. 2 million.
230

60.24 DAMBARAWA TANK
Location
In Bintenne, about 2 miles E. S. E. of Alutnuwara. Co-ordinates J122 (7.7X7.6)
Scheme
A minor work now becoming of greater utility in view of the supply from Mapakada Wewa, which in turn receives diverted conveyance from flow in Heppola Oya.
Data
Tank
Source of Supply Inlet channel from Mapakada Wewa and self-catchment 7 sq. miles Length of Tank Bund 3700ft。 Tank Full:
Storage 12,900 acre ft. Head of water 25ft, Area of water spread 850 acres
Spills:
Nature Concrete on Rock Location L.B. Length 220 ft.
Sluices:
Location L.B. R.B. Size 18" dia. 2 of 24” dia.
Inlet channel from Mapakadawewa Tank
Bed width 5ft。 Length V 2000ft。
irrigation Supply
Target for development 1800 acres of rice cultivatic n.
23

Page 140
60.25 MAPAKADA WEWA
Location
Situated close to Alutnuwara, by the 19th mile on the BibileAlutnuwara Road.
Co-ordinates J|22 (7.8x5.0)
Historical
An ancient work, the origin of which has not been identified.
Was apparently functioning during the 9th-10th centuries as indicated by an inscription of the period, in the locality.
Restoration
Restoration. 1952-53.
Data Tank
Source of Supply Diverted supply from Heppola Oya and self catchment drainage from 3 sq miles. Length of Tank Bund 1900 ft. Tank Full:
Storage 6700 acre ft. Head of water 25 ft. Area of water spread 460 acres
Spills:
Nature Channel flow Location R. B. flank Length 125ft, Sluices:
Location L.B. R.B. Size 24" dia. 24” dia.
Anicut across Heppola Oya
Length of Structure
with 9 No. openings each
144 ft. 6”×6"
fitted with lifting gates and two bays each 30 ft. wide
with permanent crest.
Irrigation Supply
The work has for target irrigation development of 1300 acres of rice cultivation.
232

60.24 DAMBARAWA TANK
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s s y s 救 S
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60.25 MAPAKADAWEWA-SLUICE

Page 141
60.26 SORABORAWEWA-SPILL
60.30 NALANDA OYA SCHEME-EBBAWELA REGULATOR
 
 

60.26 SORA BORA WEWA
Location
About 3 miles from Alutnuwara (Mahiyangana). Co-ordinates J/17 (6.1 X 2.3)
Historical
An ancient work of historical importance, which has several references. The area and the Vihare was visited by Udaya IV (946 A.C.), Vijayabahu I (1055-1110), Parakrama Bahu I (1153-1186) etc.
Restoration
Present work was restored in 1876 at an initial cost of Rs
11,405/-.
Has been improved subsequently.
Scheme
Storage Tank.
Data
Tank
Catchment area 24 sq miles Length of Tank Bund 1600ft, Tank Full:
Storage 11800 acre feet Head of water 21.7 ft. Area of water spread 1100 acres Spills:
Nature Rock Location R.B. Length 30ft,
Sluices:
Location. L.B. R.B. Size 24" dia. 24" dia.
Irrigation Supply
The work regularly benefits rice cultivation in 1700 acres,
233

Page 142
60.27 HATTOTA AMUNA
Location
At Pallegama, about 30 miles from Naula Junction and 12 miles from Elahera.
Co-ordinates J/11 (8.1 X8)
Historical
An anicut diversion scheme with 28 miles long channel, identified as Hattota Amuna was constructed during the reign of Aggabodhi II (608-618 A. C.); it is later reported to have been repaired and reconstructed by Parakrama Bahu I (1153-1186).
Restoration
The present Hattota Amuna, however, may not be the identical work; it was completed in 1952-57.
Scheme
Diversion of waters of Kalu Ganga (in the Central Province)
Data
Anicut
Catchment area 50 sq miles
Length of Structure 320 ft.
Head Sluice:
Location L.B. Size 4”×2'-6"
Irrigation Supply
The Left Bank Scheme consists of a 6 miles long channel system and aids the development of 500 acres of rice cultivation in new colonization development lands.
The projected Right Bank Scheme will benefit approximately 800 acres, similarly.
234

60.28 MAHA OYA ANCUT
Location
From Kandy to Rangalla and to Corbetts Gap and down
by newly traced road, through rubber estate to site-about 35 miles.
Co-ordinates J/16 (8.4x8.6) Construction 1956.
Scheme
Diversion anicut on wide rock site, across Karambekeliya Оya.
Data
Anicut
Catchment area 4.2 sq. miles Length of Structure 60 ft. Maximum height 5ft。 Planked bays One Head Sluice:
Size 3'x2'
Irrigation Supply
2 mile long supply channel in rugged terrain crosses drainage from Pusse Ela and other minor streams and conveys supply to 23 acres of private fields and 204 acres (102 lots of 2 acres each) for new colonization development in Meemure village. Cost of work in 1960 was Rs. 4.2 lakhs.
23S

Page 143
60.29 KARAUGAHAWELA WEWA
Location
13 miles south east of Elahera.
Co-ordinates J/7 (1.3X 1.5)
Restoration
Restoration work initiated in 1956.
Scheme
Impounds flow in Gamburu Oya.
Data
Tank
Catchment area 11 sq. miles Length of Tank Bund 。3500ft。 Tank Full:
Storage 1820 acre ft. Head of water 20 ft. Area of water spread 220 acres Spills:
Nature Structure C.O. Rock Rock Location L.B. Central R.B. Length 200ft。 120ft,155ft。 Sluices:
Location R.B. Size 24 ins. dia.
Irrigation Su ply
R. B. Channel Scheme tar et for developmnt 470 acres. L. B. system 130 acrs. Some of the R. B. lands ev ntually become absorbed in the Miripe Yode Ela Project. The work is expected to cost Rs. 6.5 lakhs (1965).
236

WVCI—NHIOAY{{SEITH VXO VOINVTVN 09°09

Page 144
60.30 NALANDA OYA RESERVOR.--SPIL
60.32 ANICUT ACROSS AMBAN GANGA
 
 

60.30 NALANDA RESERVOIR
Location
Near Nalanda; turn off westwards from 31st mile on KandyTrincomalee Road and proceed about four miles. Co-ordinates 110 (7.1 X6)
Constructed 1947-57.
Project
Tank
Nalanda Reservoir has been formed by impounding the waters of Nalanda Oya (a tributary of Amban Ganga) by a mass concrete dam.
In the dam structure is incorporated necessary spillway, for discharge of surplus water and sluices for effecting supply down the Nalanda Oya watercourse to augment Amban Ganga.
When the reservoir water level is sufficiently high, flow can also be diverted, by means of regulator gates at Ebbawela at the northern end of the reservoir.
Data
Catchment area 48 sq miles Length of Concrete Dam (at top) 402ft。 Maximum height of Dam 102ft。 Width of Dam at base 80ft。 Width of Dam at top 7ft, Head of water 70ft, Storage capacity 12,400 acre ft.
. Sluices:
Two steel pipes of 3 ft. diameter, fitted with shut off needle valves-sill 70 ft. below spill level.
Spill:
Horse shoe shaped 156 ft. long concrete spill, level three feet below top of dam.
EBBAWELA REGULATOR-FOR TRANS BASN DIVERSION
Structure with four openings each 18 ft. wide and 7 ft. high is constructed with sills about 63 ft. higher than the reservoir sluice level, for sending supply to Kala Wewa, through Welimiti Oya. The work cost Rs. 70 lakhs.
237

Page 145
60.31 BOWETENNE ANCUT
Location
Off Naula. Travel towards Elahera, from Naula (34 M.P. on Kandy-Trincomalee Road), and after 4 miles proceed 1 miles on minor road till road along channel is met.
Co-ordinates II 10 (10.2x5.5).
Scheme
Anicut across Amban Ganga, constructed in 1895 at an intial cost of Rs. 15,101/-. It was repaired and improved
in 1925.
Data
Anicut Diversion
Catchment area 187 sq. miles Length of Structure 25ft。 Maximum height 5ft, Head Sluice 6”×4碁'
Irrigation Supply
A three mile long Left Bank channel system supplies irrigation water to 230 acres of rice fields.
238

60.32. ELAHIERA CANAL Location
Near the 12th mile on the Naula-Elahera Road.
Co-ordinates of Head Works: Anicut across Amban Ganga J|6 (4.0X8.5). w
Historical
Known as the Alisara canal of old, is a work of ancient antiquity, which has several references in history. Earliest reference is construction by Vasaba (65-109 A. C.). King Aggabodhi II (608-618) is recorded to have improved it and extended to supply Giritale and Minneriya Tanks. Later Vijeyabahu (1055-1110) repaired and improved the work. It was put into good commission during the Parakrama Bahu period. It was restored in 1887 at a cost of Rs. 55,430. In 1945 it was re-commissioned and once again Amban Ganga waters augmented Minneriya Tank. It has since been improved and widened.
Scheme
The purpose of the Elahera Canal is to divert flow in the Amban Ganga for direct irrigation development and to augment supply to Minneriya and Giritale Tanks.
Data Anicut Head Works
Catchment area 538 sq miles Length of Dam ܫ ܓ (1) Anicut across Amban Ganga 380 ft. (2) Anicut across Kuda Ganga loop
95 ft. Head Sluice:
Openings: 10'x 6' and 5'x 6', fitted with steel gates on rollers. Channel
The total length of Elahera Canal, from Amban Ganga Headworks to the bifurcation structure at Diyabaduma is 20 miles. The canal is capable of conveying 1000 cusecs with 5 ft. depth; the first 900 ft. is in rock. The road crosses the channel just after 2 M.P. The Kongetta Oya (4th mile), Heerati Oya (7th mile) and the Kotapitiya Oya (12th mile) ar, among the several cross drainage streams that fall into the canal. From Bakamulla, supply is made to Minneriya and Giritale by two separate streams and channel.
Irrigation Supply
An extent of 5200 acres is directly irrigated, in tracts situated
along the lenth of the canal. Besides, the canal augments supply to Minneriya Tank and also to Giritale Tank.
239

Page 146
60.33 ATTARAGOLLAWA ANCUT
Location
Off the 16th mile on the Naula-Pallegama Road, in the Elahera area.
Co-ordinates J/1 (6.1 x 2.0) Anicut constructed in 1957-60.
Scheme
Anicut diversion of waters of Amban Ganga.
Data
Amicut ܝ
Length of Structure 518ft. Inlet Sluice 2 bays 4'x2'-6" Head Sluice:
Location R.B. Scheme. Size 5”×2”
Irrigation Supply
A main channel, over 5 miles in length with necessary field channels and offtakes has for target, water supply to 500 acres, of new colonization development in rice cultivation.
240

60.34 GRTALE TANK
Location
At Giritale, 8 miles from Polonnaruwa on the Minneriya Road.
Co-ordinates G 117 (0.5X2.2)
Historical
Identified as ''Giritala vapi'' or Giritala vava'', constructed during the reign of King Aggabodhi II (608-618); later reported as restored or enlarged by Parakrama Bahu I (1153-1186).
Restoration
Present tank restored in 1905, to hold 4000 acre ft. of water; has now been improved and enlarged during 1949-52 to hold 17,500 acre ft. of water and the new right bank colonization development project incorporated.
Data
Tank
Source of Supply:
Drainage from own catchment 9 sq. miles and also Amban Ganga flow diverted through the Elahera canal.
Length of Tank Bund 1700ft,
Tank Full:
Storage 17,500 acre ft. Head of water 40 ft. Area of water spread 760 acres Spills:
Nature Concrete Ogee Section Location . L.B. Length 125f、 Słuices:
Location L.B. R.B. Size (2'-6” X 1 "-6") 36” dia.
Irrigation Supply
The Left Bank channel supplies 780 acres. The new Right
Bank channel system aids colonization development of 3800 acres of rice cultivation.
241

Page 147
60.35 MINNERIYA SCHEME
60.35. MINNERYA TANK Location
At Minneriya, 14 miles from Polonnaruwa. Co-ordinates G/16 (12.3 X5.3)
Historical
Identified as '"Manihira vapi, foremost of the 16 celebrated reservoirs constructed by King Maha Sena (276-303 A.D.). He is still worshipped in a shrine by on the tank bund. The tank was later repaired and improved by Parakrama Bahu (1153-1186).
Restoration
Present tank restored in 1903 and subsequently improved and enlarged in 1953.
Data Tank
Source of Supply:
Drainage from own catchment of 9 sq. miles and supply of Amban Ganga diverted through the Elahera canal.
Length of Tank Bund 1 miles Tank Full:
Storage 1 10,000 acre ft. Head of water 38 ft. Area of water spread 6,300 acres Spills: Two Nos.
Nature Masonry with radial gates. Location Below Bridges on the Main Road. Length 45 ft. Sluices:
L. B. l. L. B. 2 R.B. Location Jayanthi Low Raja Ela
Sluice Level Size 3 Openings 4' x 5'-6" 3' X2'-6"
of 4' x 5'-6"
Irrigation Supply -
The Minneriya Yode Ela-Left Bank channel system over 15 miles long, commands bulk of the irrigation development area and reaches Kaudulu Oya.
The Right Bank Raja Ela irrigates over 1,400 acres of rice cultivation.
The Minneri-Kantalai Yode Ela originates from one of the tank spills. The discharge from the other feeds Kaudulla Tank.
242

60.35.1 MINNER I YA TANK R.B. SILUECE
Aos,
60.35. MINNERIYA TANK

Page 148
” محصور
60.35. MINNERYA TANK SPLL
°ካኤጭዪ: ሶቾየኬኡ J፳፱፻
60.36 KAUDULLA TANK SPLL
 
 
 

MNNERYA SCHEME 60.35.2. MINNERYA voDE ELA
The Minneriya Yode Ela takes off from the Low Level Sluice of the Tank. The Jayanthi Sluice supplies the Yode Ela.
Irrigation Development under this Ela, forms four stages, in order of development.
Stage I 4500 acres Stage II 2300 acres Stage III 2600 acres Stage IV 2568 acres
This Yode Ela is 15 miles long, the last five miles of which are extensions, to supply Stage IV of the scheme.
At commencement when it passes under the P. W. D. Road bridge the bed width is 20 ft, thereafter the section is reduced as water is delivered for irrigation en route. In the seventh mile, the railway line is crossed.
243

Page 149
60.35.3 MINNERYA - KANTALA YODE ELA
This ancient conveyance canal was devised to feed Kantalai Tank with the waters of Amban Ganga, already diverted through the Elahera canal to Minneriya Tank.
The original work is attributed to Aggabodi I (575 to 608), later it is reported as being repaired and restored during the days of Wijeyabahu (1055-1110). As a component of the well known 'sea of Parakrama it would have been in its best condition during Parakrama Bahu’s period (1153-1186).
This Yode Ela, 20 miles in length, commences from the spill on L.B. of Minneriya Tank, under Road Bridge of Habarana-Polonnaruwa Road, where three radial gates each 15 ft. by 8 ft. are installed.
The first section of the Yode Ela from Minneriya Tank to Gal Oya (stream) crossing, adjoining the Gal Oya Railway Station is over five miles in length, and the canal is 80 ft. wide capable of carrying normal discharge of 300 cusecs and flood flow of 2,800 cusecs. It flows under the railway near the quarter mile post and also feeds two small tanks Rotawewa and Matale Wewa.
The next section of the canal is from Gal Oya stream crossing to Alut Oya stream crossing, a length of 8 miles. These two stream crossings are provided with suitable gated structures to exclude flood flow; these are in the catchment of Kaudulla Tank.
Yode Ela extends from Alut Oya for 7 miles to main road crossing at Dambulla-Trincomalee Road bridge from where it flows as a natural stream-Kituluttu, into Kantalai Tank.
The last two sections were restored in 1955.
Total length 20 miles
Bed width 80 ft. Conveyance (flood) 2800 cusecs.
244

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A. 3. P

Page 150
シv:
రజ్జీ• هة تنا পািকস্তু  િદૂ
ઇ........ , છે
60.36 RADIAL GATES: KAUDULLA TANK
స్ట్రేడ్లే
60.36 KAUDULLA TANK-D/S OF SLUICE
Sc
 
 

60.36 KAUDULLA TANK
cation
About 8 miles north of Minneriya.
Co-ordinates G/12 (1.4X5.2)
storical
Identified as Tissavaddhamanaha-vapi (Rantisava) one of the 16 celebrated reservoirs constructed by King Maha Sena (276-303 A.C.) and later reported as being repaired and restored by Wijeyabahu (1055-1110). Improved by Parakrama Bahu (1153-1186).
*storation
Present restoration commenced in 1958.
Cheme
Impounds waters of Gal Oya and Alut Oya (also receives supply from Minneriya-Kantalai Yode Ela)
Data
Source of Supply:
Drainage from own catchment 32 sq. miles augmented
by flood flow from Gal Oya and Alut Oya streams and flood
flow from Minneriya Tank, through the Aggala Wan Oya.
Length of Tank Bund 5 m. 39 ch. Tank Full:
Storage • 104,000 acre ft.
Head of water 25 ft. Spills:
Nature Concrete structure
Location L.B.
Length 650ft。 Sluices:
Location L.B.
Size 4'-6”×4'-6".
Trigation Supply
The target for irrigation water supply is the development of 6282 acres of rice cultivation as new colonization. Approximate cost Rs. 17.5 million.
245

Page 151
60.37 PARAKRAMA SAMUDRA SCHEME
60.37.1 ANGAMEDILA ANCUT AND THE IN LET CHANNEL
Location
t 12 miles from Polonnaruwa, along tank and channel unds.
Co-ordinates G|21 (12.9X1.1)
Historical
Anicut and the conveyance channel, known as Akasa Ganga, and now called the Angamedila Yode Ela was constructed by Parakrama Bahu (1153-1186)
Restoration
Present work restored in 1948-1952.
Scheme
Anicut diversion of flow in Amban Ganga to Topawewa and Dambutulu Wewa.
Data
Amicut
Catchment area of Amban Ganga 540 sq miles Length of Structure 90ft, Scour Gate − - 5”×4"
Head Sluice:
Location L.B.
Size 2 openings of 10'x4'
Irrigation Conveyance Channel-Angamedila Yode Ela.
THE AKASA GANGA
Length of Channel 33 miles Bed width of Channel 50 ft. and 40ft. Depth 6 ft. Conveyance 1000 cusecs.
246

PARAKRAMA SAMUDRA SCHEME
D CHANNEL
60.37

Page 152
60.37.1 ANGA MEDI LA ANICUT
60.37.1 ANGAMEDILA ANICUT-R. B. SLUICE
 
 
 

PARAKARAMA SAMUDRA SCHEME
60.37.2 TOPAWEWA AND DAMBUTULU WEWA
Location
At Polonnaruwa.
w Co-ordinates Gf12 (5.4X8.1)
Historical
The achievements of Parakrama Bahu I (1153-1186) were prodigious. His is the immortal glory of having constructed or improved 165 dams, 3910 canals, 163 major tanks and 2376 village tanks. The pride of all is the Angamedila Anicut, Akasa Ganga, Dambutulu Wewa and Topawewa chain-called today the Parakrama Samudra.
Restoration
Present work restored in 1948-52.
Data Tank
Source of Supply:
Conveyance received through the Angamedila diversion of Amban Ganga flow and drainage from own catchment of 28 sq. miles. Tank Full:
Storage 98,000 acre ft. Head of water 22 ft, Area of water spread 5600 acres Spills:
Nature Concrete Structure with Radial gates Location On 5th mile of bund. Length 127ft, Also a natural spill. Sluices:
No. 1. D. 1 Sluice Location At 14 miles on Bund Size 4 openings of 42" dia.
NO. 2. D. 2 Sluice Location At 24 miles on Bund Size 1 opening of 4'-3"x4"
No. 3. D. 3 Suice Location At 44 miles on Bund Size 1 opening 36" dia. Irrigation Supply
D. 1 Channel System supplies 15,000 acres of rice cultivation. D. 2 Channel System supplies 2,400 acres of rice cultivation. D. 3 Channel System supplies 800 acres of rice cultivation. The work cost Rs. 33 lakhs (1950) and effects irrigation supply to 18,200 acres of rice cultivation (most of which is colonization development.)
247

Page 153
60.38 GAL AMUNA ANICUT
Minneri Oya carries the drainage from Minneriya, Giritale and Polonnaruwa areas.
Cultivation was practised in the area below these, with the aid of a temporary dam (amuna) at a rock (Gal) site-G/17 (8 x 6.6), by enthusiastic peasants.
The anicut diversion scheme commenced in 1956, provided at the site, a permanent anicut as Head Works with, data:-
Data
Anicut
Length of Structure 46 ft. with 3 Nos. Radial gates each 13'-6" x 4'-6" and overhead bridge.
L.B. Head Sluice:
3 openings 4'-9"X3'-9".
irrigation Supply
A left bank main channel system, with the aid of necessary distributary and field channels, diverts water supply for
irrigation development of 3056 acres situated between Minneri Oya and Khambili Oya.
Approximate cost Rs. 3.2 million.
248

60.38 GAL AMUNA ANICUT
༥དུ་་་་་་་་་་་་་་་་་་་་་་་་་་་ དང་
AMUNA SCHEME-SPILL CUM CAUSEWAY

Page 154
60.41.1 ACROSS THE MAHA WELL GANGA
KANTALA-ALLA ACCESS
60.41.1 ALLAI SCHEME—VERUGAL ANICUT (Under Const.)
 
 

60.39 ROTTUWAKULAM
Location
About 15 miles north of Manampitiya, off the 10th mile on the Welikanda-Tirukonamadu Road.
Co-ordinates G 118 (5.4x5.7)
Data
Tank
Catchment area 7ë sq. miles Length of Tank Bund 2700 ft. Tank Full:
Storage 650 acre ft. Head of water 10 ft. Area of water spread 165 acres Spills:
Nature Concrete Structure Location L.B. R.B. Length 80ft, 150 ft. Sluices:
Location L.B. Central Size 12" dia. 21” dia. Irrigation Supply
The work benefits the development of 275 acres of rice cultivation.
249

Page 155
60,40 MAWAKULAM
Location
About 10 miles north east of Minneriya.
Co-ordinates G|18 (5.2X2.2)
Scheme ع
Impounds the waters of Mawakulam Aru a minor stream that falls into the Mahaweli Ganga, after crossing the Welikanda-Thirukonamadu Road.
Data
Tank
Catchment area 7 sq. miles Length of Tank Bund 4200 ܫ ft.
Tank Full:
Storage 670 acre ft. Head of water 8 ft. Area of water spread 175 acres Spills:
Nature Channel flow with crest wall Location L.B. Length 400ft,
Sluices:
Location L.B. R.B. Size , 6” dia. 15" dia.
Irrigation Supply
The work benefits the development of 225 acres, with rice cultivation.
250

60.41 ALLA SCHEME
The Koddiyar Pattu, in Trincomalee is a fertile area for agricultural enterprise and several reports were prepared for its develop ment.
In 1907, a scheme to build an anicut across Verugal in place of the stick dam, cut a link channel between Mavil Aru and Verugal and deepen the Kallar channel, with a flood bund and Head Regulator at Kallar was prepared and work on this were completed by 1928, when it was formally inaugurated by H. E. Sir Herbert Stanley.
In 1941, was launched the Allai Extension Scheme by which the perennial flow in Mahaweli Ganga is conveyed for irrigatio through Mavil Aru and Verugal Head Works.
The Allai Scheme now composes of:—
(1) Anicut across Verugal Aru (2) Anicut across Mavil Aru Verugal Head Works (3) Flood Bund and Sluice (4) Kallar Inlet Channel and Head Sluices (5) L.B. & R.B. Channel Distribution System (6) Allai Tank
251

Page 156
ALLA SCHEME
60.41.1 WERUGAL HEAD WORKS
Location
Scheme
252
Is situated direct south of Trincomalee about 20 miles asthe 'crow flies.' At Verugal, 3 miles along Kallar inlet channel. Co-ordinates G18 (11.1 X2.1).
A detention tank formed by the retention of flow in the Mavil Aru and Verugal rive-both branches of Mahaweli Ganga, by means of the Mavil Aru Anicut and Verugal Anicut and the flood bunds at Verugal. As the Mahaweli Ganga is perennial, the amount detained is small and the quantity of inflow from the G. nga into these branches is indeterminate, considerable spilling overflow accommodation is required.
Data Tank − -
Catchment area ndeterminate inflow from Maha--
weli Ganga. Length of Tank bund 1 mile
Verugal Anicut Mavil Aru Anicut Nature Concrete with Concrete with 4 Radial gates Radial gates each
20' X 10." Length 197 ft. with 3 bays
each New Sluice:
Location at L.B. Size 5 openings each 6'X6'. Kallar Head Sluices:
Location L.B. R.B. Size 3 openings Two openings: each 5' x 4'-6" 4' x 3'-6" and
6”×5'-2”. Irrigation Supply
The diverted supply is led into Kallar inlet channel 3 miles long. The left bank channel system about 10 miles long, taking off from Kallar Head Sluice effects supply to new rice cultivation for colonization development. Supply is delivered into the original Kallar stream to aid the regular cultivation of the Allai and Peruvelli lands; the right bank system incorporates a 9 mile long main channel for supply to new development. In all about 10,000 acres of rice fields are benefited by the work.

ALLA SCHEME
60.41.2 ALLAI TANK
Location ܚ
South of Trincomalee, in Toppur village.
Co-ordinates G/3 (12.8 x 2.5)
Restoration
The original Allai Tank, restored in 1890, has since been modified as more or less perennial supply can be delivered to the area from the Mahaweli Ganga.
Scheme
The tank has since been reduced.
REDUCED ALLAI TANK
This work comprises of the main Allai Tank but with a reduced F. S. L. and its northern portion kept apart. Reduction of F. S. L. from the original l6.0 to 14.0 enables blocking out of the land in the fringe area for cultivation under the R. B. Scheme.
Data
Supply from Kallar drainage. . Bund top level 8.0 M.S.L.
253

Page 157
LLAKANTHA KULAM
Location
Tank
In Koddiyar Pattu, south of Trincomalee, and is approached
from the 2nd mille of Mutur-Foul Point Road.
Co-ordinates G14 (1.3X7.8)
Restored in 1891.
Data
Catchment area Length of Tank Bund Tank Full:
Storage Head of water Area of water spread
Spills:
Nature Location Length
Sluices:
Location . Size .
Irrigation Supply -
The work supplies water to 300 acres of rice cultivation.
254
13 sq miles 3600ft,
620 acre ft.
10ft, 65 acres
Masonry L.B.
185ft。
L.B. R. B. 6” dia. 12” X 12”

.
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61.1
6.1.1 KANTALAI TANK-SPILL
ནི་ད་དུ"་ད" s
క్షి కి
iiభ
GAL OYA SPILL-KANTALA YODE ELA

Page 158
64. MORAWEWA SLUICE
 

61 KANTALAI (PER ARU) BASIN
61.1 KANTALA TANK
Location
At Kantalai, 28 miles south west of Trincomalee. Co-ordinates G12 (5.7 x 1.1)
Historical
An ancient work, which has several historical references, identified as “Gangatota Vapi” or “Gangatala Vapi” constructed during the reign of Aggabodhi II (608-618). It is also the Thirukulam (Sacred tank) of Kulakoddai Arasan (circa 436) built for the upkeep of Koneswaram Temple lands at Thampalakamam. Later improved by Parakrama Bahu I (1153-1186).
Restoration
Present tank restored in 1869, to store 25 ft. of water, from own catchment. Enlarged to store 33 ft. an ancient conveyance channel Kantalai Yode Channel (constructed by Aggabodhi I 575-608) repaired from Gal Oya, Alut Oya to Kitul Utu in 1959. Vendarasenkulam was also restored and enlarged to augment the supply from Kantalai.
Data Tank
Source of Supply:
Drainage from own catchment 77 sq. miles and the the diversion of Gal Oya and Alut Oya catchments through the Kantalai Yode Ela.
Tank Full:
Storage 110,000 acre feet. Head of water 41 ft. Area of water spread . 5,000 acres Spills:
Nature Concrete structure below road
bridge. Location R.B. Length 150 ft. with 10 Radial
gates 15' x8' Sluices:
Location L.B. (Per Aar) R.B. 1 R.B. 2 (Montagna) Size 2 No. 3'x2' 3'x2' 2 bay tunnel
3基”×2” Irrigation Supply
The L.B. channel system (Per Aar) and the R.B. channel supply water for over 13,000 acres of rice cultivation and 7500 acres of sugar cane cultivation.
255

Page 159
61.2 VENDARASAN KULAM
Location
Adjoining Kantalai Tank.
Co-ordinates G12 (6.25 x200)
Scheme
Supplements supply to fields under Kantalai Tank.
Data Tank
Catchment area 4.3 sq. miles (Is also linked with Kantalai Tank) Length of Tank Bund 3800 ft. Tank Full:
Storage * 20,000 ac. ft. Head of water 39.5ft, Spill:
Nature Natural Elevation 180 M.S.L. sluices:
2 Nos. 3'6° Irrigation Supply
Benefits land under Kantalai Tank.
25b

61.3 GALMETYAWA TANK
Location
About 18 miles south west of Trincomalee, off the Trincomalee-Dambulla Road.
Co-ordinates G12 (9.75 x 8.60)
Historica
Parakrama Bahu l (l 153-1186) founded Panduvijayagama; Nissanka Malla (1187-196) is recorded to have constructed Panduvijayakulam, from an inscription found at the site.
Restoration
Restoration commenced 1960.
Scheme
Storage tank
Data
Taak
Catchment area 4. Sq. miles Length of Tank Bund 1400ft,
Tank Full:
Storage 777O acre ft. Head of water 36 ft. Area of water spread 400 acres
Spills:
Nature Channel flow Location R.B. Length : 300 ft.
Sluices:
Location Y L.B. Size i 36” dia.
Irrigation Supply
Channel system conveys supply for 600 acres of rice cultivation for new colonization development.
257

Page 160
61.4 PARAVIPANCHAN KULAM
Location
25 miles south west of Trincomalee, on the TrincomaleeDambulla Road.
Co-ordinates G12 (8.1 X5.7)
Scheme
Flood Detention tank impounding flow of Paravipanchan Aru.
Data
Tank
Catchment area 5. Sq. miles Length of Tank Bund 1400 ft. Tank Full:
Storage 4500 acre ft. Head of water 25 ft. Area of water spread 250 acres
Spills: w ,
Nature Concrete chute on rock Location R.B. Length 120ft。
Sluices:
Location L.B. Size 36” dia.
Irrigation Supply
There is no direct development under the work as such, but the supply aids development under Kantalai Tank and also helps the new settlement from flood damage by Paravipanchan Aru.
258

63. PAN OYA
63.1 ANDAN KULAM
Location
About 3 miles west of Trincomalee, on the Kandy Road. Co-ordinates D123 (4.7 x 7.6)
Restoration
Present work restored in 1885 at an initial cost of Rs. 32,953|-
Data
Tank
Catchment area 4.7 sq. miles
Length of Tank Bund w 4300 ft.
Tank Full:
Storage 1350 acre ft. Head of water 13负。 Area of water spread 20 acres
Spills:
Nature Masonry Masonry Location L.B. R.B. Length 46 ft. 100 ft.
Sluices:
Location L.B R.B. Y Size ! 2" dia. 16" dia.
Irrigation Supply
An R.B. main channel about 2 miles long and a short L. B.
channel, together supply irrigation to 460 acres, situated on either side of the Trincomalee-Anuradhapura Road.
259

Page 161
63.2 PERYAKULAM
Location
About 6 miles on the Trincomalee-Kuchchuveli Road and two miles to west.
Co-ordinates D118 (3.9 x 2.6)
Historical
Extensive archaeological ruins of places of worship in the vicinity indicate the ancient origin of the work. The cultivators even now make an annual observance to Iyanar, the presiding deity over agricultural enterprise, at the site of a huge monumental stone on the tank bund.
Restoration
The present tank was restored in 1869.
Scheme
As catchment is insufficient, is augmented by supply from Pokkankulam which has a catchment of 2 sq. miles and storage 300 acre ft.
Data
Tank
Catchment area 3 sq miles Length of Tank Bund 4100 ft. Tank Full:
Storage 1600 acre feet Head of water 10 ft. Area of water spread 275 acres Spills:
Nature Masonry Masonry Location L.B. Central Length 90ft 28 ft.
Sluices:
Location L.B. R.B. . Size 1’ X 2' 12" dia.
irrigation Supply
A total extent of 270 acres in Nilaveli village is regularly cultivated by the aid of left bank and right bank channel systems from the tank.
260

633 PERIYA ELUMPURUKKI KULAM
Location .
About 10 miles north west of Trincomalee.
Co-ordinates D118 (1.9 x 4.9)
Restoration
Restored in 1960.
Scheme
Apart from impounding flow from its own catchment, the work had, one time, been augmented by diverting supply from Pay Oya, when it would have been a major scheme
Tank
of the area.
Catchment area Length of Tank Bund Tank Full:
Storage Head of water
Area of water spread.
Spills:
Nature
Location . Length
Sluices:
Location Size
irrigation Supply
The work commands an extent of 200 acres for development
in Nilaveli village.
23 sq miles 6600 ft.
600 acre feet
7ft。 200 acres
Channel flow L.B. R.B. 300ft。 300ft。
Central l5 ins. dia.
261

Page 162
64. PANKULAM ARU I BASIN
The Pankulam is a short stream to the north of Trincomalee.
It has its source in the hills north of Kantalai, and after being impounded at Mora Wewa and at Pankulam flows into the sea near Kuchchaveli.
Hydrology
The stream is in the dry zone; the basin is 147 sq. miles in extent and is estimated to convey an average annual flow of 223,000 acre feet.
Land Use
The newly constructed Mora Wewa with the proposed extension works now in hand would utilize the commandable water flow. .
Basin Requirements
More land is available for development in the lower reaches, which can conveniently be opened up with the aid of a channel system from the reservoirs proposed in the neighbouring Yan Oya basin.
262

64. PANKULAM ARU BASIN
64.1 MORA WEWA
Location . . . . . . .
About 3 miles south of 16th mile on the TrincomaleeAnuradhapura Road.
Co-ordinates D122 (6 x 7.7)
Historical
ls an ancient work (not to be mistaken with the more well known Mora Vapi in Kala Wewa District where important events took place in the days of old.)
Restoration
Present restoration in 1962.
Scheme
Storage reservoir formed by impounding flow in Pan Oya. Part of the catchment is diverted to tanks that supply the Trincomalee Town Water Supply Scheme. -
Data Tank
Catchment area (effective) 15 sq. miles Length of Tank Bund 1600f。
Tank Full: w
Storage 27,200 acre feet Head of water 26ft, Area of water spread 1900 acres Spills:
Nature Concrete chute fall Location L.B. Length 200 ft.
Sluices:
Location R.B. Size 4豊”×4襲”
Irrigation Supply
A main channel of length 5 miles, crossing the TrincomaleeAnuradhapura Road through a syphon, along with necessary branch channels etc. effect supply for new development of 300 acres of rice cultivation, in Pankulam village and beyond. Approximate cost Rs. 5 million.
263

Page 163
64.2 ETHANDAMURPPU KUAM TANK
Location
North west of Trincomalee, about 7 miles south west of
Kuchchaveli.
Co-ordinates D112 (10.3x3.9)
Restoration
Restored about 25 years ago and subsequently improved.
Taak
Catchment area Length of Tank Bund
Tank Full:
Storage Head of water
Spills:
Nature Location Length
Sluices:
Location Size
irrigation Supply
3 Sq. miles 6500 ft.
420 acre ft.
7ft。
Channel flow
L.B. R.B. 200 ft. 300ft。
L.B. R.B.
9" dia. 9" dia.
About 200 acres are developed with supply from the work.
264

65 KUNCHU KUMBAN BASIN
65.1 GOMARANKADAWELA WEWA
Location
In Gomarankadawela village, about 5 miles to north of 17th mille on Trincomalee-Anuradhapura Road.
Co-ordinates D117 (2.2x4.4)
Data
Tank
Catchment area l: sq. miles Length of Tank Bund 2300 ft.
Tank Full:
Storage w 600 acre ft. Head of water 12ft。 Area of water spread 200 acres Spills:
Nature Concrete Location L.B. Length 100ft
Sluices:
Location Central Size 12" dia.
Irrigation Supply
About 125 acres are supplied for rice cultivation in a well settled village.
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65.2 MADAWACH(CHIYA KULAM
Location
Off the 10th mile on the Trincomalee-Anuradhapura Road. Co-ordinates D117 (2.5 x 8.3)
Restoration
Restored in 1960.
Data
Tank
Catchment area 2. sq. miles Length of Tank Bund 3700ft, Tank Full:
Storage 750 acre feet Head of water 14ft。 Area of water spread 190 acres Spills:
Nature Concrete Location L.B. Length 110 ft.
Sluices:
Location Centre
Size 12”×12”
irrigation Supply
About 300 acres of development is aided by this work.
266

65.3 NEELA PANIKIKAN KULAM
Location
North of Trincomalee, about 12 miles beyond Kuchchaveli.
Co-ordinates D112 (3.5 x 6.4)
Historical
Local tradition associates it with a one time hero named Neela Panikkan. The hillock of same name, by the side, also figures in the tradition. Restoration first taken up in 1909. Enlarged about 25 years ago and subsequently improved and enlarged.
Scheme
Formed by impounding the waters of Neela Panikkan Aru.
Data
Tank
Catchment area 10 sq miles Length of Tank Bund 3400ft。
Tank Full:
Storage 800 acre ft. Head of water ,9ft。 Area of water spread 430 acres
Spills:
Nature Concrete on rock Location L.B. Length Two spills totalling
200ft, Sluices: w
Location L.B. Size 18 ins. dia.
irrigation Supply
A channel system over 1 miles in length benefits 600 acres in Tiriyai village
267

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65.4 CHAMALANKULAM TANK
Location
About 5 miles South west of Kuchchaveli, north of Trincomalee.
Co-ordinates D112 (9.0 x 4.9)
Restoration
Restored in 1941 and subsequently improved.
Data
Tank
Catchment area 6ë sq. miles Length of Tank Bund 7100 ft.
Tank Full:
Storage XV 400 ܗܝ acre ft. Head of water 6 ft. Area of water spread 70 acres Spills:
Nature Concrete Natural Location L.B. R.B. Length 180ft。 120ft Sluices: − Location L.B. R.B.
Size 12 ins. dia. 12 ins. dia.
Irrigation Supply
Target for development 300 acres.
268

67, YAN OYA BASIN
The Yan Oya rises in the hills near Dambulla and after being impounded at Huruluwewa, flows a length of 94 miles to reach the sea south of Pulmoddai, about thirty miles north of Trincomalee.
The entire Yan Oya basin is in the dry zone and is 594 square miles in extent. The mean annual flow from the catchment is estimated to be 636,000 acre feet. There are several minor tanks dependent on the flow of its tributaries, particularly in the upper reaches of the catchment. Huruluwewa reservoir was restored a few years back, impounding the flow from 77 sq. miles of the Yan Oya catchment; but due to the unusual shape of the catchment, being narrow and long, the tank has not been filling up to full capacity regularly, every year.
Land use in the basin consists of rice cultivation and home gardens under the settlements of each of the minor tanks and the major work Huruluwewa.
Basin Requirements
There is abundant land available for development, which is now in jungle in the basin, particularly from where the Oya crosses the Anuradhapura-Trincomalee Road. There is also appreciable flow in the Oya during the North East monsoonal season. Reservoirs and schemes of development to open up the jungle lands are required.
Proposed Development
A large reservoir has been proposed near Horowupotana, called the Horowupotana Reservoir, and a smaller reservoir lower down, both of which between them would store sufficient flow to effect irrigation supply to a large extent. In fact, the scheme can function jointly along with the neighbouring basins Pankulam (on right bank) and Ma Oya (on left bank), benefiting a total extent of about 70,000
3CCS. ...'
The proposals under formulation by the U. N. S. F. Team for the development of the water resources in the Mahaweli Ganga basin, envisages the augmentation of the flow in Yan Oya by the N. C. P. supply canal; Huruluwewa would then provide assured supply to lands depending on the tank. Proposals also include (only) one new Yan Oya reservoir in the terminal reaches of the Oya, called the Yan Oya reservoir, capable of developing 27,000 acres with irrigation supply.
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67.1 HABARANA TANK
Location
At Habarana.
Co-ordinates G|16 (1.5x5.05)
Scheme
Storage Tank
Data
Tank.
Catchment area 2 sq. miles Length of Tank Bund 3940 ft.
Tank Full:
Storage 330 acre fit. Head of water 10ft. Spills:
Nature Masonry C.O. Location L.B. Length 120'
Sluices:
Location R.B. Size 18” dia. Hume Pipe
Tower Sluice.
irrigation Supply
Length of Channel one mile, irrigating 10 acres.
270

67.2 HORIWLA TANK
Location
About a mile off from the 9 mile stone on the Maradankadawela-Habarana Road.
Co-ordinates F120 (10.2x5.4)
Restoration
Restored 1952-54 and improved after flood damage in 1957.
Scheme
Impounds the flow in Horiwilla Oya,
Data
Tank
Catchment area 27. Sq. miles Length of Tank Bund 1 miles
Tank Full:
Storage 4000 acre fit Head of water 16 ft. Area of water spread 600 acres Spills:
Nature Concrete Structure Location R.B. Length 300 ft.
Sluices:
Location L.B. R.B. Size 15” dia. 15” dia.
Irrigation Supply
Left Bank Channel system about 2 miles long provides irrigation supply to 320 acres. The Right Bank Channel, crossing the spill channel by a syphon is about a mile long and irrigates 190 acres.
271

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67.3 HURULU WEWA
Location
Is situated about mile east of Yakalla village and can be
approached from Kekirawa, along 17 miles motorable road leading to Kahatagasdigiliya. Co-ordinates F115 (13.2 x 8.7)
Historical
An ancient work with reference made during King Mahasena's (276-303 A.D.) regime, when it was known as ''Challural
Vapi.”
Project
Restoration was commenced on 10.7.1949. The head works and the left bank scheme received early attention and the tank commenced holding water from 1953. Much work was done subsequently to complete the scheme. The work encountered phenomenal floods in December
1957 (Habarana 16" rain in a day) and breached disastrously for over 1100 foot wide; was subsequently restored in 1958.
Data Tank
Catchment area 77 sq miles Length of Tank Bund 8730 ft. Maximum height 81 ft. Tank Full:
Storage 55,000 acre ft. Head of water 27 ft. Area of water spread 4,000 acres Spills:
(1) (2) Nature Concrete Ogee Natural Highlevel Location Left Bank Left Flank Length 400ft, 500ft, Sluices:
Location L.B. Central R.B. Size 30" dia. 30" dia. 30” dia.
irrigation Supply
The Left Bank and the Right Bank Channel systems, each
about 10 miles long, irrigate over 4,000 acres each, consisting of private lands 750 acres and colonization area 7150 acres. About 850 acres at the end of the R.B. is augmented from Keulkada Wewa.
Capital Cost
Rs. 7 million.
272

64.1 MORAWEWA SPILL
67.3 VIHARE ON HURULUVA/FWA TANK BUND

Page 168
ĥTldS—VAARAAntı non H £'l9
 

67.4 KEULKADA TANK
Location
About 10 miles north of Huruluwewa.
Co-ordinates G.16 (6.0 x 6.6)
Historical
An ancient work, which may have functioned at the same time as Huruluwewa. Ruins of sluice structure etc. seen in the vicinity.
Scheme
Restored in 1959 chiefly to augment supply to lands in the end tracts of Huruluwewa Scheme.
Data
Tank
Catchment area 114 sq miles Length of Tank Bund 1600 ft.
Tank Full:
Storage ... " 4700 acre ft. Head of water 20ft。 Area of water spread 460 acres Spills:
Nature Clear overfall chute Location L.B. L.B. Length 100ft, 200 ft.
Sluices: سمبر
Location L.B. R.B. Size 30” dia. 18" dia.
Irrigation Supply
A four mile main channel conveys supply to Tracts 11 and 12 of Huruluwewa R.B. Scheme-extent about 850 acres.
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67.5 DIUL WEWA
Location
About two miles north of the 71st mile on the AnuradhapuraTrincomalee Road.
Co-ordinates D121 (0.7 x 1.5)
Historical
Stone ruins of Bisokotuwa Sluice indicate its antiquity, but the work has not been identified so far.
Restoration
Restored in 1952 but breached again in 1957 for the major flood of December 1957.
Data
Tank
Catchment area 6.8 sq miles Length of Tank Bund 700ft。
(High ground in between) Tank Full: 射
Storage 3000 acre ft. Head of water 22 ft. Area of water spread 350 acres Spills:
Nature Concrete and two other H.L
Structure natural spills . 60 ft. 150ft。 Location R.B. Length 60 ft. Sluices:
Location L.B. Size 24" dia.
Irrigation Supply
Over 400 acres are developed with rice cultivation, with supply from this work.
274

69, MA OYA BASIN
Physical Features
The Ma Oya is a forty mile long river in the North Eastern regions. of Ceylon; commencing in the Kahatagasdigiliya area, the stream collects drainage from 400 sq. miles and passing Kebitigollewa and Padawiya regions, empties into the sea at the Kokilai Lagoon.
The stream receives a flow estimated at 384,000 acre feet as drainage from the catchment.
Land use is dependent on the several minor tanks constructed on the tributaries and the major tank Padawiya completed recently. The main stream is thus utilized.
Proposals for development
The tributary basins have not been harnessed for water resources utilization. The proposals include a new reservoir across the northern tributary to be called Kiul Oya reservoir and to provide irrigation supply to about 2,000 acres.
The U. N. S. F. Team's proposals for development of this basin, consists of augmentation of flow in the Ma Oya by conveyance from the N. C. P. canal and the construction of three reservoirs, called the Kiulwewa, Kitulgala and the Mukunu Wewa reservoirs across the tributaries which would provide irrigation supply to a total of 86,000 acres.
275

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69.1 PADAWIYA TANK
Location
About 50 miles north east of Anuradhapura, proceeding through Medawachchiya and Kebitigollewa.
Co-ordinates Dill (1.0X3.2)
Historical
Identified as Ratmalkandha Vapi of Mahasena and Danavapi of Moggallana II (535-555 A.C.); later known as Padivapi, was enlarged and put into good order by Parakrama (1153
1 186). Nissanka Malla (1187- 1 196) decreed Padivapi a sanctuary for animals.
Restoration
Present tank restored in 1954-58.
Scheme
Storage reservoir impounding the waters of Mora Oya and Mukunu Oya.
Data Tank
Catchment area 106 sq. miles Length of Tank Bund 2 miles Tank Full:
Storage 72,500 acre ft. Head of water 22ft, Area of water spread 5,800 acres Spills:
Nature Concrete and Rock with gates Location Left Bank Length O'gee Section - 50 ft. . . Trapezoidal - 590 ft. Rock - 300 ft.
Sluices:
Location R.B. Size 3 Openings 4'x2'-6" each
irrigation Supply
An extensive channel system, on right bank only, supplies water to about 13,000 acres of rice cultivation.
Approximate cost Rs. 22 million.
276

میر
69.1 VIEW OF PADAWIYA TANK FROM CIRCUIT BUNGALOW
69.1 PADAWIYA TANK SPILL

Page 171
69.1 PADAWIYA TANK SLUICE
69.1 PADAWIYA SCHEME-CHANNEL SPILL
 
 

73. MANAL ARU (NAY ARU). BASIN
73.1 THANNIMURIPPU KULAM
Location
About 20 miles north east of Puliyankulam. Co-ordinates D11 (2.3 x 7.9)
Historical
Work of antiquity. Identified as Kurundavapi of King Aggabodhi I (575-608). Celebrated Kurantan Kulam of old, together with Kurantan ur (settlement), Kurantanmalai (place of worship) and Kurantan Cholai (parkland); reported in Sessional Paper No. XLVI of 1886 by Henry Parker.
Restoration
Restored in 1959 and subsequently improved.
Scheme
Impounds the waters of Thanikallu Aru and Periyak Aiu, tributaries of Nay Aru.
Data
Tank
Catchment area 51 sq. miles Length of Tank Bund 23 miles Tank Full:
Storage 15,000 acre feet Head of water 19ft。 Area of water spread 1500 acres Spills:
Nature Structure (C.O.) Location R.B. Length 600ft,
Sluices:
Location L.B. R.B. Size 3'-6" x3' 3'-6" x 3
Irrigation Supply
Target area for development, 3,330 acres. .
277

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74. KODALKALLU ARU BASIN
74.1 KANUKERNI TANIK
Location
About 6 miles south of Mullaitivu.
Co-ordinates B121 (5.3 x 5.1)
Restoration
Present work restored 1895-1905.
Scheme
Impounds the waters of Kodalikallu Aru.
Data
Tank
Catchment area 26 Sq. miles. Length of Tank Bund 4200 ft.
Tank Full:
Storage 200 acre feet Head of water 12ft, Area of water spread 430 acres Spills:
Nature . Structure (C.O), Location L.B. Length 300 ft. sluices:
Location L.B. R.B. Size 12" diameter 12" diameter
Irrigation Supply
The work regularly aids the development of 1250 acres of rice cultivation, in Mullaitivu area.
278

75. PER ARU BASIN 75.1 MUTHU IYAN KADDU KULAM
Location
About 15 miles east of Mankulam; is reached from Oddichuddan-on the Mankulam-Mullaitivu Road.
Historical
Earlier known as Muthu Rayan Kaddu Kulam, is referred to as "Man Malai' by Parker in Sessional Paper XLVIII of 1886, where he describes the state of work and also of the Adukku Kallu Anicut (Tekkam) across the same Per Aru about two miles below. The massive anicut is 18 feet thick, 15 feet high and over 200 feet in length.
Restoration
Scheme
Restoration commenced 1959.
The work impounds the waters of Per Aru.
Data Tank
Catchment area 66 Sq. mles Length of Tank Bund 5850 ft.
Tank Full: -
Storage 41,000 acre feet Head of water 27ft, Area of water spread 3,100 acres Spills:
Nature Structure on rock Location R.B. Length 500 ft,
Sluices:
Ilocation L.B. R.B. Size 3'-3”×4'-6" 3'-3" x 4'-6"
irrigation Supply
Target for development was 6000 acres of rice cultivation, equally divided between Left Bank and Right Bank channel systems (approx). Cultivation of subsidiary food crops has now been substituted.
279

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78. TERAVIL ARU BASIN
78.1 UDAYAR KADDU KULAM
Location
Off the 16th mile on the Paranthan-Mullaitivu Road and 3 miles to south.
Co-ordinates:- A120 (4.3x5.4).
Scheme
Formed by damming the waters of Teravil Aru.
Data
Tank
Catchment area 24 sq. mls. Length of Tank Bund 4900ft。
Tank Full: V
Storage 6500 ac. ft. Head of water 18 ft. Area of waterspread 750 acres
Spills:
Nature Structure Location L.B. Length 410ft.
- Sluices:
Location L.B. R.B. Size 24” dia 30" dia.
irrigation Supply
A two mile long channel system has a target extent of 1200 acres for development with rice cultivation.
280

79. PIRAMENTHAL ARU BASIN
79.1 VSUAWAMA DU KULLAM
Location
About 3 miles south of the 13th mile on Paranthan-Mullaitivu Road.
Co-ordinates A120 (1.8x7.6)
Scheme
Impounds the flow in Piramenthal Aru.
Data
Tank
Catchment area 12 sq. mls. Length of Tank Bund 4320 Ft. Tank Full:
Storage 3000 acre ft. Head of water 18ft。 Area of water spread 250 acres
Spills:
Nature Structure Location R.B. Length 300ft
Sluices: 1A
Location L.B. R.B.
Size 24" dia 24" dia
Irrigation Supply ·
Extent of development in rice cultivation 600 acres.
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80. NETHALI ARU BASIN
80.1 KALMLADU KULAM
Location
About 11 miles east of Kilinochchi, situated beyond Iranaimadu Tank
Co-ordinates A119 (13.0 x 6.6).
Early History
Not known, other than what the name implies, viz. a tank formed by damming low swamp (madu) at a rocky (Kal) - site. -
Restoration
Present work restored in 1951-1953 and improved subsequently.
Scheme
Impounds the waters of Nethali Aru.
Data .
Tank
Catchment area 263 sq. mls. Length of Tank Bund 4500ft, Tank Full: . .
Storage 9150 ac. ft. Head of water 21ft。 Area of water spread 1000 acres
Spills:
Nature Structure Location R.B. Length 400 ft.
Sluices:
Location L.B. Size - 30” dia.
Irrigation Supply
Target for development 450 acres of middle class new Colonization Scheme and supply of irrigation water to existing rice fields below.
282

80.1 KALMADU KULAM SPILL
śy WWW
81.3 IRANAMADU KULAM SPILL

Page 175
81.3 IRANAIMADU SCHEME–DRI ARU TANK
81.4 THONDAIMANAR BARRAGE--JAFFNA LAGOON SCHEME
 
 

81. KANAGARAYAN ARU BASIN
The Kanagarayan Aru has its source near Vavuniya and flowing in a south to north direction for over sixty miles, fills the Iranaimadu tank and eventually falls into the Elephant Pass Lagoon.
Historically it is recorded that in order to increase the flow in the river, its catchment area was extended by joining up by a cut canal, drainage from areas above Kanagarayan Kulam, which apparently was the terminal source then.
The basin is entirely in the dry zone and therefore flow in the river is limited to the North East monsoonal season only.
Land Use
Much of the basin is yet in jungle, dotted with isolated villages and settlements below minor tanks. The main development areas are under Kanagarayan Kulam and Iranaimadu Tank where about 20,000 acres are under rice cultivation.
Proposals for new development
A new storage tank has been suggested about fifteen miles above Iranaimadu Tank where about 7,000 acres could be developed.
The scope of this new proposal is visualized to be much bigger
with the proposed N. C. P. canal from the Mahaweli diversion augmenting the flow in the Kanagarayan Aru.
283

Page 176
81.1 CHIEMAMADU
Location
About 14 miles north east of Vavuniya, on the Mamaduwa Road.
Co-ordinates C110 (4.1 x 1.6)
Historical
The tank (madu) may have obtained its name from the 'shema flowering plants, often found in the jungle.
Restoration y
Restored in 1958.
Scheme
Impounds flow of the topmost reaches of Kanagarayan Aru
Data
Tank
Catchment area 14 sq miles Length of Tank Bund 5000ft。
Tank Full:
Storage 2000 acre ft. Head of water 9'-8" Area of water spread 400 acres Spills: -
Nature Structure (C.O.) Location L.B. Length 300
Sluices:
Location L.B. R.B. Size 24” dia. 24” dia.
Irrigation Supply
The work aids the development of 600 acres of rice cultivation.
284

81.2 KANAGARAYAN KULAM
Location
Situated west of 133rd mile, Kandy-Jaffna Road.
Co-ordinates C14 (12.7 x 4.5)
Historical
Original name said to be suggestive of one time colonist settlers of the Vanni-the "Rayans, along with Pallava rayan, and Akka rayan Kulams
Restoration w
Present tank restored in 1888-1896, initial cost Rs... 27,714.
Scheme
Source of Kanagarayan Aru.
Data
Tank
Catchment area 3.5 sq. miles Length of Tank Bund 6100ft。 Tank Full:
Storage 700 acre feet Head of water 11 ft. Area of water spread 160 acres Spills:
Nature Structure Structure Location L.B. R.B. Length 85 ft. 52ft。 Sluices:
Location Central Size 12" diameter
Irrigation Supply
Il rrigable arca 125 acres.
l'hic work aids rice cultivation in 75 acres.
285

Page 177
813 IRANAMADU KULAM Location
This reservoir is sited 4 miles east of Kilinochchi Town. From the Kandy-Jaffna Road, turn right at 157 M.P. and proceed along Wilson Road for a distance of 4 miles to the tank bund. Co-ordinates A119 (7.95x6.50).
Original construction:-
This is the first tank to be constructed new, by the Irrigation Department, other than the restoration of earlier works. The original proposal and estimate were prepared by H. T. S. Ward, Director of Irrigation in 1902, to hold 26' of water. Work was commenced in 1906 and completed in 1922. All work was done with manual labour by the Pioneer Labour Force. The tank was formed by joining up and damming A. (iranai) low lying swamps (madu) of the Kanagarayan
TU.
Subsequent improvement:-
The tank was raised in 1951 to hold 30 ft. and an additional sluice was constructed on the R. B. Additional lands were taken up on the R. B. & L. B. areas.
Tank Data:-
Catchment area 227 sq. miles. Length of Tank Bund 98.50' Tank Full:
Storage 82,000 ac. ft. Head of water 30': F.S.L. 57.0 M.S.L. Area of water spread 5750 acres Spills:
Nature- CIO spill Location L.B. end. Length 600' Sluices:
Location L.B. R.B. Size 5'-0" X4-0" 4՛ X27-8" Irrigation Supply:- .
L.B. Main Channel 3m. 4700' Land irrigated
private 14,908 acres Distributary 2m. 3886' Colonization
area 1,131 , R. B. Main 7 m. 400'
Distributary 2m. 4950' Colonization area 2,805 ,
Total 18,844
286

814 THE JAFFNA PENINSULA LAGOON SCHEME
Location
The name 'Jaffna Peninsula Lagoon' has become attributed individually to each and collectively to all the lagoons in and around the Jaffna Peninsula.
Within the Jaffna Peninsula there are the Vadamarachchi and the Upparu lagoons. Of these the first forms the north and east lagoons with the sea outfall and ingress at Thondamannar. The second, often referred to as the South Lagoon is linked to the sea at Ariyalai, in the outskirts of Jaffna Town.
Thc cxtcrnal lagoons i.e. Elephant Pass Lagoon and Jaffna Lagoon are to the east and west of Elephant Pass. The Elephant. Pass Lagoon stretches from Elephant Pass to the eastern fringe of the Peninsula at Chundikulam. The Jaffna Lagoon is the sheet of water west of Elephant Pass and is the largest of them all.
Historical
It has been said that the lagoons in the Jaffna Peninsula were formed by subsidence due to subterranean deposits getting dissolved.
In 1879, Sir William Twynam refers to a tradition that these lagoon areas were once cultivated lands, without any sea water entry. He promoted a scheme for their reclamation.
In 1916, due to persistant requests of Mr. Horsburg, an attempt was made to prevent salt water entry into the East Lagoon, and to retain at least a foot of fresh water.
Scheme
Rcclamation of the areas, by shutting off any further sea water entry and its gradual replacement by fresh water.
JAFFNA PENINSULA LAGOON SCHEME THE WADAMARACHCH LAGOON location
Thc sca outfall of this lagoon is through Bridge near the 7 tile on the Pallai-Valvettiturai Road, 13 miles north of Jffn.
(o-ordinates A123 (0.8 x 4.0)
istorical
Thondamannar (Thondai-mannaru) is said to have been excavated by Thondai-mann to provide safe shelter to fishing craft against the fierce North East monsoonal storms.
287

Page 178
Scheme
Unfortunately the Thondaimannaru also provides entry for sea water to inundate and render saline over 5000 acres.
The ingress is particularly heavy during the heavy blowing. and high seas of the North East monsoonal season.
Project consists of a barrage across the outfall.
Data
Thondamannar Barrage Structure Catchment area l 1.5 sq miles Length of Barrage 613 ft. Permanent Spillway:
Length w 200ft, Solid Crest 2.50 M.S.L. Top of planking 4.00 M.S.L Gated Openings:
Total No. 18 Gate Size: Upper 20"×4s Lower: 20"×4" Crest Level of Barrage (Gates closed position) 4.0 ft. above M. S. L. Sill of Planking in Permanent
Spillway 2.5 ft. above M.S.L.
Sill of Bottom of 18 No. Gateways 3.5 ft. below M.S.L. Area inundated by sea water (the
North & East Lagoon) 7300 CeS
The work cost Rs. 11 lakhs in 1948.
JAFFNA PENINSULA LAGOON SCHEME
THE SOUTH LAGOON
Location
The sea outfall of this lagoon is through the Bridge in the 196th mile on the Jaffna-Kandy Road, 4 miles south east of Jaffna.
Co-ordinates A12 (10.1 X 2.2)
Scheme
288
Sea water enters, driven particularly by the South West monsoonal winds, through the bridge and renders waste about 1500 acres of land. Project consists of a semi-circular spill across the outfall.

JAFFNA PENNSULA LAGOON
CONVERSION TO FRESH WATER LAKE
A NAKA RAYAN A
MAA) MULA M4 ***
· VAV VMAYA.
A... .

Page 179
814 ARIYALAI SPIELL SOUTH LAGOON
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81.4 ELEPHANT PASS LAGOON
 
 
 

Data
Salt Water Exclusion Structure
Catchment area 85 sq. miles 150 ft. radius, Circular Structure- Length 540 ft. Openings:
10 Nos. wooden gates 5'-6"X5 ft.
32 Nos. Planked Openings 5 ft. wide. Crest Level of Structure 4 ft above M.S.L. Sill Level of Openings 1 ft. below M.S.L. Area of water spread 6400 acres.
JAFFNA PENINSULA LAGOON SCHEME
ELEPHANT PASS LAGOON
Location
At Elephant Pass stretching east of the 116th mile on the Kandy-Jaffna Road, about 30 miles south east of Jaffna.
Scheme
The bed of the lagoon, 19,000 acres in extent, has been rendered saline by sea water entry from the west (during South West monsoon) through the bridge at Elephant Pass and from the east (during North East monsoon) by the collapse of the sand bar openings at Chundikulam.
The project envisages the prevention of such ingress and the conservation of fresh water, draining down the Kanagarayan Aru. It was first thought of in 1879, and later pressed for
in 1928.
Data
Catchment area 474 sq miles Length of Bund at Elephant Pass 2 m. 3740 ft.
(Bridge closed) Length of Bund cum spil at Chundi
kulam 1 m, 4700 ft.
Spill:
Length 2000ft。 Sill level 2.5 M.S.L. Planking 2.0 ft. Link Channel:
Length 2 miles
289

Page 180
815 NLAWARA PUM.PNG SCHEME
PUTTUR
Location
At Puttur, a village two miles west of 10th mile on the JaffnaPoint Pedro Road.
Ni lawarai
The “Tidal Well at Puttur, usually known as the Nilawarai, appears on the surface very much like an ordinary rectangular pit or "kerni’’, but unlike others it is 164 ft. 6 inches deep.
The well is of approximate dimensions 50 ft. by 40 ft. at the surface but widens out to an undefinable subterranean cavern beneath the top land crust.
Water level is about 0.2 feet below mean sea level and is of the highest potable quality down to a depth of 50 ft. Presence of dissolved impurities become evident below that level and the water contained below 80 ft. depth is comparable to sea water; below 130 ft. the contents are even heavier than sea water with more dissolved solids.
Pumping Project
290
Pumping tests were carried out in 1946 to ascertain the quantity of water that could be drawn daily without making a permanent lowering of the water level and without affecting the wells in the vicinity.
Based on the 1esults of tests, a pumping irrigation development project has been promoted to supply water for the
cultivation of subsidiary food crops in 250 acres and has
been working satisfactorily since 1950.

83. AKKARAYAN ARU BASIN
83.1 MURHANDY TANK
Location
About 7 miles west of the 150th mile on Kandy-Jaffna Road.
Co-ordinates A124 (0.50x8.00)
Historical
An ancient village by which is found the original shrine, in commemoration of which is founded the new Murihandy way side temple at 151; M.S. on Kandy-Jaffna Road.
Data
Tank
Catchment area 7ë sq. mls. Length of Tank Bund 9500ft。
Tank Full:
Storage 1800 ac. ft. Head of water 9ft。 Area of water spread 420 acres Spills:
Nature Structure Location R.B. Length 240 ft.
Sluices:
Location L.B. R.B. Size 18" dia, 18” dia.
irrigation Supply
Aids development of 420 acres of rice cultivation.
291.

Page 181
83.2 AKKARAYAN KULAM ,
Location
About 10 miles west of Murihandy (152nd mile) on KandyJaffna Road.
Co-ordinates A118 (13.5 x 4.0).
Historica
An ancient work, the antiquity of which is not known.
Restoration
Present work restored in 1953-54 and subsequently improved.
Data
Tank
Catchment area 45 sq. mls. Length of Tank Bund 5600ft。
Tank Full:
Storage 17,000 ac. ft. Head of water 2量ft, Area of water spread 2000 acres Spills:
Nature Channel flow High Level Location . L.B. R.B. Length 600' 200'
Sluice:
Location L.B. R.B. Size 36” dia. 2 of 12" dia. each
Irrigation Supply
L. B. channel system aids the development of 2000 acres and the R. B. 1000 acres, of rice cultivation.
292

83.2 AKKARAYANKULAM SPILL
85.2 KARIYALA NAGAPADUVAN TANK-CENTRAL SPILL

Page 182
86.1 VAVUNIKULAM R. B. SLUICE
86.1 VAVUNIKULAM R. B. CHANNEL TROUGH
 
 
 

84. MANDEKAL ARU BASIN
The Mandekal Aru along with the neighbouring eastern basinAkkarayan Aru, together drain an extent of 181 sq. miles. Both these are north east monsoonal basins which are dry during the other months. They have their source near Puliyankulam and flow in a north westerly and northerly course for about twenty five miles each, before falling into the sea on either side (west and east) of Poonakeri.
These basins are estimated to have a total annual yield of 72,400 ac. feet, out of which about 50,000 ac. ft. can be expected to be available for storage with reasonable success from year to year.
Land Utilization
Existing schemes at Akkarayankulam, Vannerikulam, Maniyar Kulam etc., aid the development of about 6,000 acres; the balance area is in jungle.
Proposed development
A long low dam built to impound the flow from both the basins in one reservoir, sited above Poonakeri, would largely aid to sustain the underground water table of this dry arid region, facilitating domestic water supply and also providing irrigation water supply. The irrigation benefits will first accrue to the large extent of about 3,000 acres, now cultivated with rice, subject to the vagaries of direct rainfall. The proposed reservoir should also benefit about two thousand acres of new lands.
293

Page 183
84.1 KODIDA KADDINA KULAM
Location
About 13 miles S. W. of Murihandy (152nd mile) on KandyJaffna Road.
Co-ordinates A123 (11 x 7.5).
Commenced in 1961.
Data
Tank
Catchment area 9 sq. mls. Length of Tank Bund 8000 ft. Tank Full:
Storage | 880 ac. ft. Head of water 8ft. Area of water spread 520 acres Spills:
Nature Structure Channel flow Location L.B. R.B. (H.L.) Length 380' 100' Sluices:
Location L.B. Size 24" dia. Irrigation Supply
Irrigation development of 400 acres of rice cultivation.
294

84.2 AMBELAPERUMAL KULAM
Location
About 11 miles S.W. of Murihandy (152nd mile) on KandyJaffna Road.
Co-ordinates A123 (11.2X8.7).
Restoration
Restoration work, 1960.
Data
lank
Catchment area 24 sq. mls. Length of Tank Bund 2 miles
Tank Full: -
Storage 3050 aC. ft. Head of water 9ft。 Area of water spread 700 acres
Spills:
Nature Structure Location At 1st mile on Bund Length 675 ft. wann
Sluices:
Location L.B. R.B. Size 2 of 18" dia. 18” dia.
Irrigation Supply
Target for irrigation development 1000 acres of rice cultivation.
295

Page 184
843 VANNER KULAM
Location
About 12 miles direct west of 152nd mile on Kandy-Jaffna Road.
Co-ordinates A118 (7x3.6).
Historical
Location suggests it having been across and impounding waters of Iyankan Aru: later probably due to breaching and dwindling population became separate tank without a river Supply, but only a tank (eri) with direct rainfall (van).
Restoration
Restored in 1950 and subsequently improved.
Data
Tank
Source of supply:
Regulated inflow from Iyankan Aru and from
Catchment area 5 sq. mis. Length of Tank Bund li mls. Tank Full:
Storage 1700 ac. ft. Head of water 8ft。 Area of water spread 350 acres Spills:
Nature Structure Location L.B. Length 300ft, Sluices:
Location L. B. Size 18" dia.
Inlet channel from Iyankan Aru.
Irrigation Supply
Aids cultivation development of 700 acres-new colonization.
296

85. PAL LAVARAYAN KADDU BASIN
85.1 TENNIYANKULAM
Location
In the Tunukai area of the Jaffna District N. P., situated about 5 mls. N.W. of Tunukai and approachable also from Pallavarayan Kaddu.
Co-ordinates A123 (7.9 x 5.8).
The Project
An ancient work formed by damming, Terrankandal Aru, also called Tenniyankulam Aru further down. Improvement work consists of detaining the flow of the main aru, without allowing it to escape at the right flank and other necessary works.
Data
Tank
Catchment area 17.75 sq. mls. Length of Tank Bund 2 mls. 1500 ft.
Tank Full:
Storage 4,400 ac. ft. Head of water 10 ft. Area of water spread , 940 acres
Spills:
Nature Masonry C.O. Location R.B. Length 500ft, Sluices: L.B. R.B.
18” dia. 18” dia.
irrigation
Irrigable land extends on both banks and are catered for by left bank and right bank channel system. About 250 acr s of cultivated land and over 500 acres new land are commandable for irrigation water supply.
297

Page 185
85.2 KARYALA NAGAPADUWAN TANK
Location -
About 3 miles east of 18th mile on Pooneryn-Mannar Road, As 18 (3.4x 1.9)
Restoration
Commenced in 1960.
Scheme
mpounds the flow in Pallavarayan Kaddu Aru.
Data
Tank
Catchment area 55 sq. mls. Length of Tank Bund 4 miles Tank Full: :
Storage 7700 aC. ft. Head of water 10 ft. Area of water spread 1400 acres Spills:
Nature Structure Structure Location L.B. R.B. Length 400ft。 400 ft. Sluices:
Location L.B. R.B. Size 24” dia. 24" dia.
Irrigation Supply
Target for irrigation development rice cultivation in 1500 aCeS.
v298

86. - PAL ARU BASIN
Pali Aru basin, known to have been well developed even during the pre-Christian era, complete with its then Pali Wavireservoir and Pali Nagaram township, has its source near Puliyankulam and flows in a north westerly course for over forty miles before reaching the Sca.
The river drains an area of 176 sq. miles and about 163,000 acre feet of water flows in the stream annually.
Land Development
A new reservoir, Vavunikulam, has been completed recently across this stream; this work will aid the development of about 20,000 acres, for cultivation of rice, highland settlement and for other associated purposes, all around the village of Tunukai.
Proposals for development
An additional reservoir, to be called the Pali Aru reservoir, can be sited below the Vavunikulam Scheme. Such a reservoir would receive drainage from about 125 sq. miles and aid the development of about three thousand acres of direct cultivation.
The proposals of the U.N.S.F. Team include an upper reservoir, above Vavunikulam called the Pali Aru reservoir to be augmented with the flow diverted to Pali Aru by the N. C. P. canal. This along with a similarly placed Parangi Aru reservoir in the neighbouring basin is envisaged to aid irrigation supply to 45,000 acres in addition to the seven thousand acres already under irrigation.
299

Page 186
86.1 VAVUNKULAM
Location
Is situated about 10 miles S. W. of Mankulam.
Historical
Peliwapi, as this work was known in the olden days, is referred to as lying in a breached condition as far back as 161 B.C., the era of King Dutugemunu (Mahavansa XXVII. 39-41). Local tradition also attribute the ancient name ''Bhavani' to this work.
Restoration work was commenced in 1954, with aid from
• the Australian Government under the Colombo Plan.
Data
Tank
Catchment area 88 sq. mls. Length of Bund w 2 miles
Tank Full:
Storage 35,300 ac. ft. Head of water 24 ft. Area of water spread 3150 acres Spills: (1) (2) (3)
Nature: Concrete Chl. Ch.
C.O. Location R.B. R.B. L.B. Length: 700' 1200' 500'
Sluices:
3 Nos. L.B. Central R.B.
4x3' 18" dia. 4X3" |
Irrigation Supply
The work benefits 6000 acres of rice cultivation for new development.
The right bank scheme, with a channel over 8 miles long commands the Tunukai area, nearly 3000 acres in extent.
The left bank scheme benefits a similar extent.
300

88. PARANGI ARU
Parangi Aru has its source in the Vavuniya-Omaintai region and flows westwards for about 40 miles before reaching the sea near the plains of Illuppai Kadavai.
The stream drains a catchment area of 325 square miles and the flow in the stream is assessed as 266,000 acre feet. There are a few minor village irrigation works in the catchment and three somewhat larger works near the source.
Existing land use is entirely dependent on the above tanks. Overall, it can be said that the bulk of the basin yet remains to be developed.
Proposals for development
Proposals formulated consist of two major reservoirs, the first the “Upper Parangi Aru Reservoir in the upper regions above Mundumurippu and the second the “Lower Parangi Aru Reservoir' being an enlarged and augmented Kurai Tank.
The Upper Parangi Aru reservoir, along with the similarly situated Pali Aru reservoir in the adjacent basin would aid the development of 45,000 acres with irrigation supply.
The Lower Parangi Aru reservoir would be somewhat smaller and may be able to command about two to three thousand acres.
30

Page 187
88.1 MADUKANDE TANK
Location
Near 3rd mile on Vavuniya-Horowupotana Road.
Co-ordinates C115 (1.3x0.6)
Historical
The area is celebrated as one of the places where the sacred ''Tooth Relic' was lodged on the journey from India to Anuradhapura. The tank has been once known as Mandu Kotte Tank, from the tree ferns 'mandu' that flourish on the hill. -
Restoration
Restored 1886-96, initial cost Rs. 19.807.
Data
Tank
Catchment area 44 sq miles Length of Tank Bund ,3550ft, Tank Full:
Storage 1400 acre feet Head of water 13ft, Area of water spread 270 acres Spills:
Nature Channel Structure Structure Location L.B. 1 L.B. 2 R.B. Length 50ft。 46 ft. 146 ft.
Sluices:
Location L.B. R.B. Size m 9" dia. 12” dia.
irrigation Supply
Extent of 400 acres depend on this work for irrigation water Supply.
302

88.2 VAWUNIYA TANIK
Location
At Vavuniya. Co-ordinates C/14 (12.4 x 1.7)
Historical
Once known as Villam Kulam, was one of the earliest tanks. to be restored.
Restoration
Present work restored in 1887.
Data
Tank ܗܝ
Catchmeh area 10 sq. miles Length of Tank Bund 5200 ft.
Tank Full:
Storage 1620 acre feet Head of water 12 ft. Area of water spread 350 acres Spills:
Nature Structure (C.O.) Channel Location L.B. R.B. Length 352量。 136 ft.
Sluices:
Location (i) , (ii) Size 12" dia. 9" dia.
Irrigation Supply ;
The work supplies irrigation water for cultivation of rice in 427 acres and also for the civic amenities of Vavuniya Town.
303

Page 188
88.3 MAMADUWA TANK
Location
About 6 miles north east of Vavuniya. Co-ordinates C/15 (1.7x5.0) .
Historical
Believed to be a work of very early origin; reported to have been repaired during the reign of Kassapa V (914-923 A.C.).
Restoration -
Restored in 1888-96, initial cost Rs. 16,396.
Data Tank
Catchment area 264 miles Length of Tank Bund w 6480ft.
Tank Full:
Storage 3030 acre feet Head of water 12'-9" Area of water spread 600 acres Spills:
Nature Masonry Natural Location L.B. R.B. (2 spills) Length 100 ft. 375鲁、 Sluices: (i) (ii) (iii)
Location L.B. L.B. L.B. Size 9” dia. 12" dia. 9" dia.
irrigation Supply
The work aids development of 760 acres of rice cultivation in Mamaduwa village.
304

Location
88.4 MAHA RAMPAI KULAM
About two miles east of 114th mile on Kandy-Jaffna Road. Co-ordinates C114 (13.2 x 4.1)
Restoration
Restored in 1888-96, initial cost Rs. 16,712.
Data
Tank
Catchment area 6 sq. miles Length of Tank Bund 3850 ft.
Tank Full:
Storage 640 acre feet Head of water 10 ft. Area of water spread 160 acres Spills: (i) (ii) (iii)
Nature Structure Structure Structure Location L.B. L.B. R.B. Length 100 ft. 59ft。 60ft
Sluices: /
Location L.B. w R.B. Size 12" dia.
Irrigation Supply
The work aids cultivation of 226 acres.
305

Page 189
88.5 KALMADU KULAM
Location
About 10 miles north east of the 10th mile on VavuniyaMannar Road.
Co-ordinates C14 (4.0 x 7.2)
Scheme
Kalmadu is sited below Periyakaddu, to impound the waters of Periyakaddu Aru, and as its name would imply, it is a low ground (madu) with rock (kal) out crops along the bund line on L. B. ܬܐ
Restoration
Restored-1953-57.
Data
Tank
Catchment area 24 sq miles Length of Tank Bund ,5700ft,
Tank Full: −
Storage 200 acre ft. Head of water 8ft。 Area of water spread 350 acres Spills:
Nature Concrete Structure-C.O. Location L.B. Length 400 ft.
Sluices:
Location - R.B.
Size 18 ins.
Irrigation Supply
A Right Bank Channel System over 7 miles long conveys
supply for the development of 400 acres of rice cultivation for new colonization.

88.6 PALAVI TANK
Locatioп .
About 10 miles north of the 10th mile on the VavuniyaMannar Road.
Co-ordinates C19 (2.6 x 4.0)
Scheme
Impounds the waters of Periyakaddu Aru.
Data
Tank
Catchment area 48 sq miles Length of Tank Bund 2 miles Tank Full:
Storage 12,000 acre ft. Head of water 22ft, Spills:
Nature Structure-C.O. Location R.B. Length 835ft,
Sluices:
Location L.B. R.B. Size 24 inches dia. 24 inches dia.
Irrigation Supply
Target for development under the work-2500 acres of irrigated rice cultivation.
307

Page 190
88.7 PANANKAMAN TANK
Location
From Mankulam to Vavunikulam and from there about four miles to village and tank.
Co-ordinates C/3 (13 x 13.3
Historical
The name suggests a farm settlement (Kamam) of (Panar) which may have functioned when the city of Pali Nagaram and the large tank Peli Wavi. flourished in the neighbouring Vavunikulam area.
However, later said to be the Head Quarters of one of the Vanni kings: in the area are found abandoned wells, temples and other signs of ancient habitation.
Data
Tank
Catchment area and augmentation
from Konayan Kulam 1.5 Sq. miles Length of Tank Bund 4900 ft. Tank Full:
Storage 600 acre ft. Head of water 7ft。 Area of water spread 150 acres
Spills: ܫ
Nature - Structure-C.O. Location L.B. Length 200ft。
Sluices:
Location Two Sluices Size - 9 ins. and 6 ins.
Irrigation Supply
308
The work aids irrigation development of 200 acres of rice cultivation.

88.8 KURA TANK
Location
About 6 miles east of 17th mile on Mannar-Poonakeri Road. Co-ordinates C/3 (1.30x3.50).
Historica
The work, very likely, is an unfinished (kurai) reservoir, conceived to function (like Giants Tank Scheme and Tekkam Diversion) along with partly completed anicut across Parangi Aru, five miles up; this comprehensive project had received a set back during the construction period.
Restoration
The tank (Kurai Tank) has since been restored to function by itself-1961.
Data
Tank
Catchment area 3ë sq. miles Length of Tank Bund 2 miles
Tank Full: .
Storage 600 acre feet Head of water 10 ft. Area of water spread 350 acres Spills:
Nature Channel flow with crest wall. Location Central Length 200ft。
Sluices:
Location L.B. R.B. Size - 24 ins. dia. 24 ins. dia.
irrigation Supply
Target for irrigation development 500 acres.
309

Page 191
89. NAY ARU BASIN
89. PERYA THAMPANA KULAM
Location
About two miles north of the 15th mile on the VavuniyaMannar Road.
Co-ordinates C113 (9.7x3.3)
Historical
The first of the larger tanks across the Nay Aru (in the West of N.P.); H. W. Parker refers to the earlier work that had existed at the site in the ancient days in Sessional Paper No.
XLIX of 1886
Restoration
Present tank restored in 1956.
Scheme
Impounds the waters of Nay Aru (upper raches).
Data
Tank
Catchment area 23 sq. miles Length of Tank Bund 5200ft,
Tank Full:
Storage 1100 acre feet Head of water 9 ft. Area of water spread 250 acres
Spills:
Nature Concrete Location L.B. R.B. Length 300 ft. 300ft。
Sluices:
Location - L.B. R.B. Size 18” dia. 18” dia.
Irrigation Supply
for the development of 350 acres of rice cultivation for a thriving colonization project.
30

88.8 SETTLERS AND ENGINEERS AT KURA I TANK
89.2 PERYAPANDIVIRCHCHAN TANK SPILL

Page 192
قره ، تلفن ... میان آنظقه
89.4 PERIYA MADU TANK
90.1 NACHCHADUWA TANK
 
 

89.2 PERIYAPANDIVIIRICHCHAN KULAM
Location
About 6 miles north west of the 15th mile on VavuniyaMannar Road.
Co-ordinates C/13 (7.4 x 4.5)
Restoration
Present work restored in 1952-57.
Scheme
Impounds the flow in Nay Aru, situated below Periya Thampanai Kulam in the same valley and as its name would indicate is an important (Pandu) largely spread out (Virich
chan) tank.
Data
Tank
Catchment area 32. Sq. miles Length of Tank Bund 7000ft, Tank Full:
Storage 2800 acre ft. Head of water 11 ft. Area of water spread 600 acres
Spills:
Nature Structure (C.O.) Location L.B. Length 750ft,
Sluices:
Location L.B. R.B. Size 18 ins. dia. 18 ins. dia.
irrigation Supply
The work effects irrigation water supply for the development of 900 acres of rice cultivation, situated near Madhu Church.
311

Page 193
89.3 THACHCHIANA MARUTHAMADU
Location
About 3 miles north of Madhu Church.
Co-ordinates C18 (5.7x2.7)
Restoration
Restored in 1951-54.
Scheme
Impounds the flow of Nay Aru, being another tank in the Nay Aru basin.
Data
fank
Catchment area 43 sq miles Length of Tank Bund 4900ft。
Tank Full:
Storage 580 acre feet Head of water 5 ft. Area of water spread 300 acres Spills:
Nature Structure C.O. Location Central Length 600 ft.
Sluices:
Location L.B. Size 12 ins. dia.
irrigation Supply
The work supplies water for rice cultivation in over 100 acres.
312

89,4 PERIYA MADU
Location
About 10 miles east of the 12th mile on Mannar-Poonakeri Road.
Co-ordinates C18 (3.9 x 7.8)
Scheme
The one before the last of the series of tanks in the Nay Aru Basin and as its name would imply it is comparatively a large (Periya), low swamp (Madu), bunded up to form a tank.
Restoration
Restored in 1952-57. Has subsequently breached and been repaired.
Data
Tank
Catchment area i 142 sq. miles Length of Tank Bund 1 miles
Tank Full:
Storage 4500 acre feet Head of water 12ft。 Area of water spread 560 acres Spills:
Nature Channel flow with structure. Location R.B. Two spills Length 1000 ft. and 1500 ft.
Sluices:
Location L.B. R.B. Size 30 ins. dia. 48 ins. dia.
Irrigation Supply
Left Bank Channel system extending 6 miles, aids the develop
ment of 750 acres of rice cultivation in Widatal Thivu area, as new colonization.
313

Page 194
90. ARUVI ARU BASIN
The basin is referred to as Malwattu Oya in the upper reaches and Aruvi Aru in the lower reaches. Though it is the second largest basin, but being situated in the dry zone monsoonal area the amount of yield from the basin is not very large.
It is one of the earliest basins to be settled, even from prehistoric
days. There are about 1450 working tanks in this basin, some
of them large (and with long history) but most of them are working minor irrigation schemes.
Among the larger reservoirs are Nachchaduwa, Tissa Wewa, Nuwara Wewa, Maha Kanadarawa, Iratperiyakulam, Pawat Kulam and Giant's Tank.
Malwattu Oya rises at Ritigala Hills (2,514 ft.) and draining the Dambulla and Anuradhapura areas passes Medawachchiya and falls into the Gulf of Mannar, near Chilvathurai, opposite Mannar Island. Its length is 104 miles.
Hydrology
The extent of the Malwattu Oya basin is 1,433 sq. miles. The basin depends entirely on the North East monsoonal rainfall and the average precipitation in the catchment annually is 56 inches, and the total annual yield is 1 million acre feet. Flood problems have not been very severe, though opening of the spill gates at Nachchaduwa has caused inundation of properties in Anuradhapura town.
Land Use
The upper segment of the basin is fairly well developed with the large reservoirs, rice lands, villages and the several minor irrigation works all over the area. Improving these, maintaining them in good working order and extending them to aid larger areas of development would be the pattern of land use in the region.
The lower region however is yet in jungle and provides scope for new development. −
Water Resources Utilization
For the judicious use of the unexpended yield from the catchment a site for the construction of a storage reservoir has been selected about 25 miles from the sea outfall. The extent of the drainage of the Oya at this site is 832 sq. miles. Details are listed further down.
Irrigation
Several large scale, medium scale and minor irrigation development schemes utilise the water resources of the basin.
314

Domestic Water Supply
Supply for Anuradhapura town is drawn off from Nuwara Wewa. The quantity is small and presents no problem except during periods of severe drought.
As in all dry zone basins, the demand is for the storage of available flow for aiding irrigation supply.
Proposals for development
The Technoprom export organisation of the U.S.S.R. has prepared a project report for the construction of a reservoir, at the site mentioned earlier for storing 282,000 acre feet of water to irrigate 32,000 acres of land to be developed newly and for effecting supply to the nearly 20,000 acres of land already developed under Giant's Tank and Akathi Scheme. Cost of project Rs. 80.7 million.
The U. N. S. F. Team envisage the construction of two new reservoirs at Tirapane and at Kapirigama which, along with the proposed Malwattu Oya reservoir is expected to provide irigation supply to 71,000 acres of new land development, in addition to the 41,000 acres already cultivated under the existing major tanks Nachchaduwa, Nuwara Wewa, Maha Kandarawa, Sangilikandarawa, Pavat Kulam etc.
315

Page 195
90.0 MANANKATYAWA TANK
Location
Is situated about 20 miles S. E. of Anuradhapura and 5 miles west of Huruluwewa.
Co-ordinates F115 (9.3 x 7.5)
Scheme
Storage Tank
Data
Tank
Catchment area 23.8 sq. mls. Length of Tank Bund 5300 ft.
Tank Full:
Storage 8300 ac. ft. Head of water 18ft,
Spills:
Nature Concrete Structure Location R.B. Length 100ft。
Sluices:
Location L.B. R.B. Size 2”×2” 4”×3”
Irrigation Supply
Extent benefited 1800 acres.
316

90.1. NACHCHADUWA TANK
Location
About 10 miles south east of Anuradhapura.
Co-ordinates F/19 (10.1 x2)
Historical
Attributed to King Moggallana II (535-555 A.C.), a great tank builder and identified as Pattapasana Vapi of old.
Later reported as being repaired and restored by Vijeyabahu (1055-1110). -
Restoration
Present tank restored in 1906 and improved in 1917. The breaches that occurred in 1957 were repaired in 1958.
Scheme
Impounds the waters of Malwattu Oya and Maminiya Oya from the Habarana area.
Data Tank
Catchment area 236 sq. miles'
and supply from Kalawewa, through Kalawewa-Yode Ela by new link channel. .
Length of Tank Bund One mile
Average Height 35ft。
Tank Full:
Storage 45,100 acre ft. Head of water 25ft。 Area of water spread 4,400 acres
Spills:
Nature Concrete on rock Location Right Bank Size 467 ft. with three gates 9"x 7'-6"
each.
Sluices:
Location L.B. 1 L.B. 2 R.B. (H.L.) Size 2 of 4" dia. 3 " X 2" 3 of 4'x3'-6" Extrasluice to supply Nuwara Wewa-Yode Ela: Openings 8 of 4 ft. dia.
317

Page 196
Irrigation Supply
318
The long left bank channel system-(consisting of an upper channel 10 ft. higher than the lower channel), conveys supply to rice cultivation and also augments flow in K.Y.E. to Apura reaching the outskirts of Anuradhapura. These supply water to over 5400 acres.
The ancient Yode Ela (excavated during the reign of King Moggallana II), now almost a natural stream flowing down to Nuwara Wewa is from a small spill at the Right Bank. A new sluice and a proper channel has now been constructed to feed Nuwara Wewa.

90.1 NACHCHADUWA TANK SPILL
90.2 NUWARA WEWA

Page 197
90.4 BASAWAKKULAMA TANK
90.5 MAHAKANDARAVA TANK & SLUICE
 
 

90.2 NUWARA WEWA
Location
At Anuradhapura. Co-ordinates F.19 (6.5 x 7.8)
Historical
One of the city tanks of Anuradhapura the origin of which belongs to the antiquity of the pre-Christian era. Identified as ''Nakara vavi recorded as having existed during the reign of Gaja Bahu I (114-136); was enlarged and improved to form large work and for augmentation, a feeder channel was cut from Nachchaduwa Tank (then Pattapasanavapi). during the reign of Moggallana II (535-555).
Restoration
Present work was restored in 1890 at an initial cost of Rs. 65,307|-.
Data
Tank
Source of supply:
Drainage from own catchment of 32 sq. miles and also augmentation from Nachchaduwa down special sluice via ancient canal.
Length of Tank Bund 4 miles Average Height 35 ft. Tank Full:
Storage 36,000 acre ft. Head of water 23ft。 Area of water spread 3,000 acres Spills:
Nature Masonry Masonry Location L.B. R.B. Length 13 f, 30ft. Sluices:
Location Central R.B. Size 2 of 20” dia. 2 of 20" dia.
Irrigation Supply
Total extent of 2400 acres depend on this work for regular irrigation supply. The Anuradhapura town water supply is drawn from this tank, which apparently had always been one of its functions in early days.
319

Page 198
90.3 TISSA wEwA
Location
At Anuradhapura. Co-ordinates F/9 (4.1 x8.2)
Historical
The construction of the original Tissa Wewa (Tissa Vapi) is ascribed to Devanampiya Tissa (250-210 B.C.); subsequent references relate to enlargement of the work by later monarchs.
Scheme
Present tank was restored in 1889.
Data
Tank
Source of Supply:
Conveyance from the Kala Wewa-Yode Ela (terminus), own catchment 2 sq. miles. Length of Tank Bund 1 miles Tank Full: r
Storage 2900 acre ft. Head of water 17 ft. Area of water spread 450 acres Spills:
Nature Masonry Channel Location L.B. R.B. Length 60 ft. 35ft。 Sluices:
Location L.B. R.B. Size 12”×12” 12”×12”。 and Bassawakkulama supply outlet 3”×3"
Irrigation Supply
Regular supply to 1000 acres of rice cultivation.
320

90.4 BASSAWAKKULAMA TANK
Location
In the city of Anuradhapura. Co-ordinates F|4 (4.4X0.3)
Historical
Probably the most ancient work in Ceylon, identified as ''Abhayawewa and associated with the reign of Pandukabhaya, 4th Century B.C.
Restoration
Present tank restored in 1874 at an initial cost of Rs. 69,5911-.
Data Tank
Has own catchment area of 33 sq. miles, but receives in . addition supply from Tissa Wewa. Length of Tank Bund 3,900 ft.
Tank Full:
Storage 1900 acre ft. Head of water 16 ft. Area of water spread 265 acres Spill:
Channel flow with structure has 9 bays. Length 100 ft.
Sluice:
Size 2'-4" X '-6".
Irrigation Supply
An extent of 916 acres are benefited with irrigation supply from this work; an important function of Bassawakkulama however is the provision of water for civic needs of the pilgrims etc. for which purpose five feet of water is always reserved.
32

Page 199
90.5 MAHA KANADARAWA TANK
Location
About 4 miles north east of Mihintale. Co-ordinates F13 (0.3 X2.1)
History
ls identified as "Kanadiyadora or Khanu Vapi of ancient times, constructed by King Maha Sena (276-303 A.C.); later referred to as Maha Kanadara Wewa, when a feeder channel was constructed to it during the reign of Sena II (853887) by the construction of a dam at Maradankadawela (Khattanta Nagara) and 12 miles long canal. Later reported as being repaired and restored by Vijayabahu (1055-1110) and improved by Parakrama Bahu (1153-1186).
Restoration
Present restoration commenced 1958.
Scheme
The reservoir is formed by impounding the waters of Kanadara Oya, a tributary of Malwattu Oya.
Data Tank
Catchment area 26 sq. miles Length of Tank Bund li miles Tank Full:
Storage 32,300 acre ft. Head of water 18 ft. Area of water spread 3,400 acres Spills:
Nature On Rock Ogee on rock with
Y 2 gates 20' x 10' Location Centra R.B. Length 600 ft. 320 ft.
and High Level (Central) spill 300 ft. Sluices:
Location L.B. R.B. Size 3基”×4場” 3場”×4場”
Irrigation Supply
322
The work benefits 6000 acres equally divided between the left bank and right bank channel systems.
The left bank main channel crosses the Mihintale-Medawachchiya Road and also the Anuradhapura-Medawachchiya Road and flows towards Parasanga Wewa. The right bank irrigation system extends towards Mahagalkadawela.

90.5 MAHAKANDARAWA DEVALAYA
90.9 PAVATKULAM SPILL

Page 200
ኣከኋ፩
ལྷོ་ 鹽
90.10 MANIAR KULAM
90.1 1 CHEDDIKULAM
 
 

90.6 SANGILKANDARAWA TANK
Location
East of the 9th mile of Anuradhapura-Medawachchiya Road. Co-ordinates C/25 (0.7x2.5)
Restoration
Present tank restored in 1907.
Data
Tank h
Catchment area 63ë sq. miles Length of Tank Bund 7000ft,
Tank Full:
Storage 3140 acre feet Head of water 12ft. Area of water spread 650 acres Spills: No. 1 No. 2 No. 3
Nature f Masonry Masonry Masonry Location L.B. L.B. R.B.
Length 400 ft. 270ft, 75ft。
Irrigation Supply
The work supplies irrigation facilities to 850 acres; the channel system crosses the Anuradhapura-Medawachchiya Road at the 90th mile.
323

Page 201
90.7 MEDAWACHCHIYA TANK
Location
At Medawachchiya, 15 miles north of Anuradhapura.
Co-ordinates C/24 (12.3X3.9)
Restoration
Present tank restored in 1876; it breached due to excessive
Tank
rains in 1923 and was repaired. the big flood of December 1957.
Catchment area Length of Tank Bund
Tank Full:
Storage Head of water
Area of water spread
Spills:
Nature Location Length
Sluices:
Location Size
Irrigation Supply
The work supplies water for regular cultivation of 275 acres.
324
It suffered damages during
16 sq miles 300 ft.
150 acre feet 11 ft. 180 acres
Masonry L.B.
82 ft.
L.B. R.B. 12” dia. 6” dia.

90.8 IRATPERIYA KULAM
Location
East of 108th mile on Kandy-Jaffna Road, in the village by the same name.
Co-ordinates C/19 (11.1 x 6.5)
Historical
The inscription found on the rock in the embankment, records the visit of Gaja Bahu I (112-134 A.C.) to the shores of “ ‘Alawichcha Lake. ”” .
Restoration
Present tank restored in 1886-1896, initial cost Rs. 25.556.
Scheme
Impounds the flow of Kal Aru.
Data
Tank
Catchment area l2 sq. miles Length of Tank Bund 5320 ft.
Tank Full:
Storage 3500 acre feet Head of water 15 ft. Area of water spread 525 acres Spills:
Nature Structure Location R.B. Length 142 ft. sluices:
Location L.B. Central R.B. Size 12" dia. 18" dia. 10" dia.
Irrigation Supply
The work regularly aids the development of 550 acres of rice cultivation.
325

Page 202
909 PAVAT KULAM
Location
About 6 miles west of Vavuniya.
Co-ordinates C/19 (7.3x4.1)
Historical
Believed to be of very ancient origin, may even be preChristian. Had breached and overgrown for several centuries. A small portion of the reservoir had however been restored as an independent tank called 'Ullukulama'.
Restoration •
In 1958, the comprehensive work has once again been restored.
Scheme
Impounds the waters of Kal Aru and Kallukundamadu Aru.
Data Tank
Catchment area | 15 sq. miles Length of Tank Bund 2 miles
Tank Full:
Storage 27,000 acre feet Head of water 19ft。 Area of water spread 3,000 acres
Spills:
Nature Rock & Structure with four Structure Radial Gates 20 ft. Location Central R.B. Length 650 ft. 400 ft. Sluices:
Location L.B. R.B. Size 42” dia. 4”×3'-6"
Irrigation Supply
Left Bank Scheme irrigates Olukulama and Mathuvaithakulam fields and new colonization development, in all 2000 aCCS.
Right Bank channel aids new development of 2000 acres of rice cultivation, making in all 4000 acres.
326

90.10 MLANLARİ KULLAM
Location .
About two miles south of 10th mille on Vavuniya-Mannar Road.
Co-ordinates C/14 (1.5 x 0.1)
Restoration
Restored in 1952.
Data
Tank −
Catchment area 14 sq miles Length of Tank Bund 2900ft,
Tank Full: h−
Storage 700 acre feet Head of water 10 ft. Area of water spread 140 acres Spills:
Nature Rock Location V− L.B. Length 250ft,
Sluices:
Location R.B. Size 2" dia.
Irrigation Supply
The work aids development of 160 acres of rice cultivation.
327

Page 203
90.11 CHEDDIKULAM
a Location
East of 37th mile on Mannar-Medawachchi adjoining the village and railway station with the same
ale.
Co-ordinates C/18 (13.2x3.7)
Historical
Has been known as Vengala Cheddikulam; the site is said to be one time Head Quarters of the eldest of three brothers
who ruled over adjoining areas-others being Nadu (middle) Cheddikulam and Sinna (youngest) Cheddikulam.
Restoration
Tank
Present tank restored in 1892.
Catchment Area Length of Tank Bund
Tank Full:
Storage Head of water
Area of water spread
Spills:
Nature Location Length
Sluices:
Location Size
Irrigation Supply
328
Irrigable area 125 acres. The work aids rice cultivati
5. sq. miles 3850ft。
700 acre feet
11 ft. 160 aCeS
Structure Structure
L.B. R.B. 85ft, 52ft。
Central
12" diameter
on in 75 acres.
Road and

90.12 MARUTHAMATIDU
Location
About 2 miles north of 44th mile on Medawachchiya
Co-ordinates C/24 (3.3 x 6.6)
Scheme
Impounds the waters of Naruvili Aru (upper reaches).
Data
Tank
Catchment area − 14 sq miles Length of Tank Bund 3800 ft.
Tank Full:
Storage 1500 acre feet Head of water 12ft。 Area of water spread 275 acres
Spills: V
Nature Structure Structure Location L.B. R.B. Length 100ft,150ff。
Sluices:
Location L.B. R.B. Size 9” dia, is 9" dia.
Irrigation Supply
Over 400 acres are cultivated with irrigation supply from
this tank.
329

Page 204
90.13 MUHATHAN KULAM
Location
Adjoining the 39th mile on the Medawachchiya-Mannar Road.
Co-ordinates C118 (12.5 x 1.8)
Historical
Tradition associates the area with temples and holy places at the nearby Vavale Lake, by the banks of Malwattu Oyathen known as “Kadamba Nadhi'.
Restoration
Present tank restored in 1953.
Scheme
Impounds the waters of Naruvili Aru.
Data
Tank
Catchment area l5 sq. miles Length of Tank Bund 6000 ft.
Tank Full:
Storage 2400 acre feet Head of water 11 ft, Area of water spread 400 acres Spills:
Nature Channel flow Location L.B. Length 630 ft.
Sluices:
Location R.B. Size 24” dia.
Irrigation Supply
The work aids development of 800 acres of rice cultivation in Cheddikulam area.
330

90.14.1 SUSPENSION BRIDGE TO TEKKAM

Page 205
90. 14.1 TEKIKAM
90. 14.3 GIANTS TANK-...-HEAD SLUICE
 
 

90.14 GLANT'S TANK SCHEME
90.14.1 THE TEKKAM (DIVERSION ANICUT)
Location
About a mile South of 26th mile on Medawachchiya-Mannar Road.
Co-ordinates C/13 (4.8x0.6)
Historica
Malwattu Oya-“the Kadamba Nadhi”” of ancient days and Aruvi Aru in Mannar District is dammed by a “Tekkam” (obstruction) about 22 miles from its mouth. The structure is massive about 12 feet high, 640 feet long and “full breadth 90ft.””
Scheme
The flow in the river is headed up and diverted by the Tekkam
to (i) Giant's Tank by means of the inlet channel and (ii)
Akathimurrippu Scheme by an L.B. Channel.
Data
Anicut Diversion
Source of Supply: Aruvi Aru (Malwattu Oya)
Catchment area 1168 sq miles Length of Structure 685ft, Height 12ft, Crest Level 70.39 M.S.L.
Right Bank Scheme
Inlet channel (Alawakkai) to Giant's Tank benefits 15,000 3CCS.
Left Bank Scheme
Akathimurippu Scheme main channel benefits 4500 acres.
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Page 206
GLANT'S TANK SCHEME
90.14.2 THE ALAWAKKA
(INLET CHANNEL TO GIANT'S TANK)
The Alawakkai conveys the diverted flow, from the Tekkam to Giant's Tank and is about 15 miles in length.
The present channel was designed by H. Parker in 1881 (and construction commenced in the following year) to the following dimensions:-
Bed width 70ft。 Depth of water 5 ft. 6 ins. Conveyance 800 cusecs Gradient 1 in 7500 Maximum velocity of flow 2 f. p. s.
On the 16th of November 1900, the Engineer in charge was happy to send 'a stream of water 70 ft. wide and 4 to 5 ft. deep down the Alawakkai for the first time from the Aruvi Aru, the water 'found its way through the breaches (yet unrestored) in the Giant's Tank Bund’’.
The Head Sluice control is sited very near the second mile post along the channel.
Immediately above the Head Sluice is the 70 ft. spillway to discharge unwanted water through Sittaru, back to the river.
At 6 mile, the channel crosses the main road, from Medawachchi to Mannar under P. W. D. Bridge near the 20, M. P.
Also along the channel are to be found spills, flood outlets and three main water issue sluices for irrigation needs.
332

90.14.3 GIANT'S TANK
Location
Between the 11th and 15th miles on the Mannar-Medawachchiya Road.
Co-ordinates G/12 (7.8 x 7.2)
Historical
Nicholas considers the possibility of this work being identical with 'Mahanama Matha Vapi, a tank in the north with 17 mile canal’’ augmentation, constructed during the reign of King Dhatusena (459-477) and which was later listed as one of the tanks restored by Parakrama Bahu I (1153-1186). Its restoration was very vigorously mooted in the 18th - century, during the administration of Van de Graaff under the Dutch regime, but nothing happened. The subject was revived in 1880, with a motion in the State Council, dated September 29th, 1889 by Sir P. Ramanathan and its restoration commenced in the following year to be completed after several delays (due to epidemics, death of the I. E. etc) on the 30th November 1902.
Locally it is referred to as 'Sodayan Kattu Karei" or the giant built embankment.
Data Tank
Source of Supply:
Inlet Channel (Alawakkai) from the Tekkam (Malwattu Oya diverted flow) and own
Catchment area of 38 sq miles Length of Tank Bund 4 miles Tank Full: − Storage 26,600 acre ft. Head of water 10'-4" Area of water spread 4,550 acres Spills:
Nature Channel flow Location R.B. Length 172ft。 Sluices:
There are seven sluices:
Irrigation Supply
With a total net work of over 24 miles of main channel and equal length of branch channels, water is conveyed from the sluices to several minor irrigation tanks all over the irrigable area.
333

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90.14.4. AKATH TH MURRPPU CHANNEL
Location
Takes off from the Tekkam.
Historical
334
H. Parker who inspected the work in 1881, presumes that it was never a completed work. In Sessional Paper I of 1881 he describes the condition of the work, then. This probably is a higher channel.
The Akaththimurrippu Scheme of to-day was promoted in
1928, as a new left bank project from the already existing, Tekkam (of Giant's Tank Scheme) and conveys surplus flow feeding several village tanks terminating with Akaththimurrippu Tank.
The channel is 14 miles long and has the following data:-
Bed width 7.
Depth 4'-6" Slope 1 in 5000 Conveyance 83 Cusecs.

90.4.3 GIANTS ANK
90.14.3 GIANTS TANK-D/S OF CHANNEL

Page 208
90.14.4 AKKATHIMURIPU INLET CHANNEL & SLUICE
పళ్లభణిశభః
92.2 MODERAGAM ARU ANICUT
 
 
 

92. MODERAGAM ARU BASIN
The Moderagam Aru has its source near Anuradhapura and flows westwards by the Wilpattu National Park, separating the Puttalam and Mannar Districts, reaching the sea at Marichchukaddi.
Hydrology
This dry zone stream has a catchment area of 364 sq. miles and the annual average flow amounts to 252,000 acre feet.
Resources Development
Besides a few village tank projects in the upper catchment close to Anuradhapura, the flow in the Aru is impounded at Mahawillachchiya; a new scheme and a diversion weir at the historical site called Pilmadu Tekkam diverts supply to a storage tank called Viyadi Kulam. −
Basin Plan
Due to the location of the Wilpattu National Park, which is a national asset, any further large scale development in this basin may not be desirable.
335

Page 209
92.1 MAHA WILLACHCHYA VEWA
Location
Is situated about 18 miles north west of Anuradhapura. Co-ordinates F13 (4.1 x 7.8)
Historical
Believed to be a work of very ancient antiquity, the origin of which has not yet been identified. 'Mayettivapi is recorded to have been improved and the bund enlarged during the reign of Udaya II (887-898).
Restoration y
Present tank restored in 1955-58.
Scheme
The tank is formed by damming the waters of Talawe Oya, which is known as Moderagam Aru, further down. In view of the close proximity of Wilpattu National Park
Reserve, development of the area under the work is restricted
to 2500 acres.
Data
Tank
Catchment area 142 sq. miles Length of Tank Bund 1 miles Tank Full:
Storage 32,500 acre ft. Head of water 37ft。 Area of water spread 2,400 acres Spills:
Nature Concrete Structure Location L.B. Length 400 ft. Sluices: -
Location L.B. R.B. Size 3'-6” dia. 3'-6” dia.
Irrigation Supply
L. B. and R. B. channel system together convey supply for the development of 2500 acres of rice cultivation.
336

92,2 MODERAGAM ARU ANCUT
Location
About 10 miles east of Marichchikaddi which is a village 32 miles south of Mannar.
Co-ordinates CI22 (8.8x2.9)
Historical
An anicut site with the ruins of an 8 ft. anicut of large boulders, 40 ft. thick and 80 ft. long (called the Ussayppu Kallu Tekkam) placed in lime mortar. A partly excavated channel (Alavakka) took off on the R. B. presumably to feed a tank Periya Kattu about five miles away, on the same pattern as the Malwattu Oya, Tekkam and Giant’s Tank. H. Parker's report on the work appears in Sessional Paper No. 1 of 1881.
Restoration
Present work restored in 1962.
Scheme
Diversion of flow in Moderagam Aru, known as Talawa Ela in the upper reaches and across which the Mahawillachchiya Tank is constructed. The area of the anicut headworks is in proximity to the Wilpattu Game sanctuary.
Data
Anicut - .
Catchment area 336 sq. miles Length of Structure 340 ft. Spills:
Nature C.O.
Location On flank
Length 30 ft. Sluices:
Location R.B.
Size 3 of 36 inch pipes.
Irrigation Supply
The diverted flow augments supply to Viyadikulam and other tanks in Marichchikaddi area, by a conveyance channel over 5 miles long.
337

Page 210
92.3 VIYADI KULAM
Location
About 4 miles east of Marichchikaddi village, which is 32 miles south of Mannar.
Co-ordinates Cl22 (4.2 X 5.2)
Historical
This work, referred to once as ''Periya Kattu' kulam was apparently originally conceived to receive the diverted flow from ''Ussayppu Kallu Tekkam,' a function in the same way as Giant's Tank. It was reported as having a bund five miles long.
Restoration
Restoration commenced in 1960.
Data
Tank
Source of Supply:
Diverted conveyance from Moderagam Aru and drainage
from own catchment of 3 sq miles Length of Tank Bund li miles Tank Full:
Storage 840 acre ft.
Head of water 8ft,
Area of water spread 300 acres . Spills:
Nature C.O.
Location L.B.
Length 500 ft.
Sluices:
Location L.B.
Size 12 inches dia.
Irrigation Supply
The work aids development of rice cultivation in 150 acres of land and to augment supply to other village tanks e.g. Attikuli Tank in Marichchikaddi village.
338

93, KALA OYA BASIN
The Kala Oya has its source near Nalanda and flows for 97 miles in a north-westerly direction passing Dambulla, Kala Wewa, Rajangana and reaches the sea near Pomparippu.
Hydrology
This dry zone Oya draining an area of over a thousand sq. miles, is impounded at the historical Kala Wewa tank where the catchment area is 323 sq. miles and, again, at Rajangana reservoir, where catchment area is 622 sq. miles. The average annual flow in the Oya is 860,000 acre feet, of which 72,600 acre feet is impounded at Kala Wewa and 81,600 acre feet at Rajangana. There are several other smaller and minor tanks in the region.
Land Utilization
The upper reaches of the Kala Oya basin are fairly well utilised by development under the Kala Wewa, Siyambalagamuwa, Rajangana, Angamuwa and several other major & minor irrigation schemes.
The lower basin is yet undeveloped.
Proposals for development
A lower Kala Oya reservoir is proposed a few miles below the Puttalam-Anuradhapura road crossing. Such a scheme would aid the development of over 8,000 acres with irrigation supply; a total development of about 20,000 acres in all could be envisaged up to the western sea coast.
Among the proposals for the development of the water resources of the Mahaweli Basin, recommended by the U.N.S.F. Team, is the Bowatenna-Kala Oya canal, which would augment the flow in this basin. As a result, the development of a total area of 78,000 acres of irrigated cultivation, is envisaged in the basin.
339

Page 211
93.1 KANDALAMA TANK
Location
of Dambulla.
Co-ordinates F/25 (11.6x2.7)
Scheme
The tank was formed by damming Mirisgoni Oya. Restoration work was done during the years 1952-1957 and the tank re-constructed to aid the development of the area
Tank
around Dambulla town.
Catchment area Length of Tank Bund
Tank Full:
Storage Head of water
Area of water spread
Spills:
Nature Location Length
Sluices:
Size Head
Irrigation Supply
The right bank channel system benefits an extent of 2080 acres including 350 acres of the Govt. Farm, through which it passes, crossing the Trincomalee Road to Randeni Wewa Tank and later parallel to the Anuradhapura Road.
340
This storage reservoir is situated about 3 miles to the east
37.7 sq miles 3200 ft.
24,400 acre ft.
28 ft. 1,700 acres
Masonry on rock At Left Bank entrance 260 ft.
R.B. L.B.
3 " dia. 3" dia. 28 ft. 26 ft.
The left bank system is not so extensive.

93.1 KANDALAMA TANK-SLUICE

Page 212
93.2 DEWAHUWA TANK—SLU ICE
93.2 DEWAH U WA TANK-SPL t
 
 

93.2 DEWAHUWA TANK
Location
At Dewahuwa about five miles from Galewela, on GalewelaKekirawa Road and westwards one mile to tank bund.
Co-ordinates II5 (1.7 x 6.7)
Early History
Local legend narrates the story of Dutugemunu receiving pirith thread (“huiya”) from the Gods (Dewa) when camping at this site.
Restoration
There were two tanks Dewahuwa and Palu Rotawewa, which were made into one large tank in 1950.
Data
Tank
Catchment area 26 sq.miles Length of Tank Bund 4300ft,
Tank Full:
Storage 7750 acre feet Head of water 25 ft. Area of water spread 850 acres Spills:
Nature Concrete structure on
rock. Location L.B. Length ,600ft,
Sluices:
Location R.B. Size 3 ft. diameter
Irrigation Supply
Colonization development of 2336 acres with rice cultivation is aided by a 9 miles long R. B. channel system, lying above and below main road; the channel crosses main road near 7th mile. The road along tank bund proceeds to Moragolla. The work cost Rs. 17 lakhs in 1950.
34

Page 213
93.3 KALA WEWA SCHEME
933.1 KALA WEVA
Location
About 30 miles south east of Anuradhapura and 10 miles from Kekirawa.
Co-ordinates F120 (0.8 x 0.7)
Historica
The celebrated Kalavapi reservoir (as Kalawewa was called then) of ancient history was constructed during the reign of Dhatusena (459-477). Several subsequent references make mention of the repairs etc. done at various times, e.g. Mahinda II (777-797) improved and strengthened the work. The Kala Oya valley was dammed by a five mile long earthen embankment, sixty feet high to impound the waters of Dambulla Oya and Heen Ela just below their confluence.
Present tank was restored in 1887 and enlarged by 6 ft. in 1939; the 1957 breaches were repaired in 1958, and the twin tanks Kalawewa and Balaluwewa merged to form one large
reservoir.
Data
Tank
Sources of Supply:
Drainage from own catchment area 323 sq. miles and supply from Nalanda Reservoir by Welimiti Oya.
Length of Tank Bund:
Kalawewa 1 m. 1600 Balaluwewa 1 m. 1900
Tank Full: メ
Storage 72,700 acre ft. Head of water 30ft。 Area of water spread 6,400 acres Spills:
Nature Concrete Masonry Location Central Length 600 ft. and a long high level natural spill at the L.B. end Sluices: (i) (ii) (iii)
Location Yode Ela Goda. Ela Balaluwewa Size 3 of 2 of 27" dia 2 of 27" dia.
2”×2'-9” ۔۔۔۔
342

93.3.ł KALAWEWA
93.3.1 KALAWEWA SPILL WATERS

Page 214
933.2 KALAVEVA Y()) A
93.4 KATTIYAWA TANK
 
 
 

Channels:
R.B. -Yode Ela (Jaya Ganga), 54 miles long to Anuradhapura, Kahagama channel 15 miles long takes off near 5th mile on Yode Ela.
L.B. --Balalu Ela - 2 miles
Goda Ela - Short length.
Irrigation Supply
The work supplies water to 12.700 acres of rice fields direct.
343

Page 215
KALA WEWA, SCHEME
93.3.2 KALA WEWA YODE ELA (JAYA GANGA)
Receives supply from the Yode Ela sluice at Kala Wewa, size 3 openings each 2 X2'-9"; this ancient canal cut during the reign of Dhatusena (459-477), is a masterpiece of engineering skill. It is 54 miles long flowing from Kala Wewa to Anuradhapura; it conveys supply to 60 minor tanks en route, to the Kagama Branch channel, to Nachchaduwa Tank and the City Tank of Anuradhapura.
It was restored in 1889 at an initial cost of Rs. 295,750/-.
It crosses the Kekirawa-Anuradhapura main road at the 7th mille and can also be seen near the 9th, 10th, 16th & the 19th miles
of the same road.
The Kagama Branch channel takes off from the 5th mile of the Yode Ella.
344

93.4 KATTY AWA TANK
Location
is situated about 3 miles to the south on the road which
branches off near the 14 mile stone on the AnuradhapuraMaha Illuppallama-Kekirawa Road.
Co-ordinates F114 (5.3 x 0.8)
Historical
An ancient work-Kativapi was restored by Parakrama (1153-1186).
Scheme Y
Restored in 1950-1952 to impound the waters of Kattiyawa . Ela, containing the waste waters of Maha Illuppallama and other tanks. v
Data
Tank
Catchment area 34 sq. miles Length of Tank Bund 5000ft, Tank Full:
Storage 2750 acre ft. Head of water 12ft。 Area of water spread 400 acres Spill:
175 ft. long, rock face, clear over fall spill at R.B. Sluice:
One 24" dia. pipe.
irrigation Supply
A three mile long channel system irrigates 500 acres of development area.
345

Page 216
93.5 SIYAMBALANGAMUWA TANK
Location
About 6 miles to the west of Kala Wewa, is reached by travelling northwards about 4 miles from Moragallagama Railway Station.
Co-ordinates F124 (9.5 x 7.2)
Historical
An ancient work, believed to have been put into working order during Parakrama Bahu’s period-the 12th century.
Restoration
Present tank restored in 1956.
Scheme
Storage tank impounding flow in the upper reaches of Siyambalangamuwa Oya.
Data
Tank
Catchment area 18 sq miles Length of Tank Bund 3800ft。
Tank Full:
Storage 1300 acre ft. Head of water 17ft。 Area of water spread 260 acres
Spills:
Nature Concrete structure on rock Location R.B. Central R.B. Length 240 ft. 160 ft. 80 ft.
Sluices:
Location L.B. R.B. Size 3 ft. dia. 3. ft. dia.
Irrigation Supply
The left bank channel supplies 250 acres and the right bank channel an extent of 160 acres for rice cultivation, for new colonization development.
346

93.6 USGALA SIYAMBALANGAMUWA wEwA
Location
About 6 miles north east of Galgamuwa.
Co-ordinates F118 (12.7x6.7)
Historical
This very ancient work (correct name Siyambalangamuwa which was changed recently to Usgala Siyambalangamuwa to avoid confusion with another work of the same name about 15 miles up-stream) is presumed to be one of the works of King Maha Sena (276-303 A.D.), later, King Mahinda II (777-797) is recorded to have excavated a 16 mile channel from Kalawewa to augment this work identified as 'Santinigamakavapi. The area was the scene of an important battle. It had apparently been reduced to a smaller work subsequently and in the days of Bhuvaneka Bahu (1534-42) is said to have benefited about 750 acres.
Restoration
Was investigated for restoration in 1878 by Mr. Cotterill. Restoration was taken up in 1955. h−
Data Tank
Catchment area 7 sq. miles Length of Tank Bund 4700 ft. Tank Full:
Storage 22,000 acre ft. Head of water 21 ft. Area of water spread 1,900 acres Spills:
Nature Concrete Concrete Location R.B. 1 R.B. 2 Length 140ft。 276ft。 A short length of spill discharging into the oya is also constructed in the L. B.- Total 450 ft. Sluices:
Location R.B. L.B. Size 3 " dia. 3 " dia.
Irrigation Supply
The right bank channel commands 950 acres and the left bank channel system an extent of 622 acres for new coloniz
ation development with rice cultivation. Approximate cost Rs. 3 million. −
347

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93.7 (HALA KALAN KUTTTYA TANK
Location
Situated about 10 miles west of Kala Wewa.
Co-ordinates F/19 (6.3 X5.9)
Restoration
The work was improved in 1956.
Scheme
Impounds the flow in Kalan Kuttiya Ela.
Data
Tank
Catchment area 25 sq. miles Length of Tank Bund One mile
Tank Full:
Storage 1000 acre ft. Head of water 12 ft. Area of water spread 70 acres
Spills:
Nature Concrete Structure Location R.B. Length 370ft。
Sluices:
Location L.B. R.B. Size 2" dia. 12" dia.
Irrigation Supply
Provides irrigation supply for the development of 330 acres of rice cultivation.
348

93.8 RAJANGANA RUINS

Page 218
  

Page 219
93.9 ANGAMUWA WEWA
(RAJANGANA SCHEME)
Location
About 6 miles west of Tambuttegama.
Co-ordinates F/13 (6.6x4.9)
Historical
Angamuwa Wewa-'Angagama Vapi-of old is recorded
as being one of the tanks restored by Parakrama Bahu
(1153-1186). Ruins found in the vicinity are said to be of Anulapavata Maha Vihare—1st and 4th century inscriptions.
Restoration
Present restoration--1956.
Scheme
Impounds the waters of Lunu Oya, a tributary of Kala Oya.
Data
Tank
Catchment area 50 sq miles Length of Tank Bund 1 mile Tank Full:
Storage 1 1,700 acre ft. . Head of water 20 ft. Area of water spread 1,100 acres Spills:
Nature Concrete Structure with 2 gates each 20' x 10' Location Central Length . 500 ft.
Sluices:
Location L.B. R.B. Size 24" dia. 24" dia. Irrigation Supply
This work forms part of the Rajangana Scheme; the sluice discharges into the R.B. channel of the Rajangana Scheme and benefits 2000 acres.
350

95. 1.1 ABAKOLA WEWA

Page 220
95.1.2 ATTARAGALLA TANK-SPILL
99.1 DEDURU OYA ANICUT
 
 

95. MI OYA BASIN
The Mi Oya has its source in the Galgamuwa-Maho area and flows westwards for sixty seven miles, before reaching the sea at Puttalam.
The stream drains an area of 592 sq. miles and is assessed to have a flow of 121,000 acre feet, during the north-east monsoon.
Land use is dependent, in the dry zone, on irrigation water supply. Existing works in the upper reaches consists of the recently completed Mi Oya Diversion Scheme and Tabbowa Tank which is constructed across Nanneri Oya, a tributary of Mi Oya. There are several minor works in the basin.
Proposals for development
Two major reservoirs are proposed; the upper Mi Oya reservoir at Inginimitiya and the lower Mi Oya reservoir (Rajawanni Reservoir) about five miles from Puttalam. A smaller reservoir can be erected in the upper reaches of Nanneri Oya.
As the amount of water in the basin is not sufficient to effect irrigation supply to all the commandable lands and as the neighbouring Deduru Oya basin has spare flow, diversion of Deduru 'Oya flow to the Mi Oya basin would be of advantage. In which event an extent of about 50,000 acres could be developed in the combined project.
351

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95.1 MI OYA DIVERSON SCHEMIE
The nature of the Scheme that apparently existed in the area, consisted of a diversion anicut across the Mi Oya, diverting flow to Attaragollawa Tank for purposes of irrigation supply under that tank.
The present project consists of storage reservoir cum diversion of the Mi Oya at Abokalawa Tank, feeding Attaragollawa from where supply is also made to Palukadawela Tank where the bulk of the development is undertaken.
These three tanks of the Mi Oya Scheme chain are about a mile apart and are connected by inlet channels each 40 and 35 ft. wide.
352

MI OYA DIVERSON SCHEMIE
95.1.1 ABAKOLA WEWA
Location
3 miles south east of Ambanpola.
Co-ordinates F/23 (10.7 x 4.1)
Present tank constructed in 1954.
Scheme
Impounds, detains and diverts flow in Mi Oya for , direct
irrigation supply and to feed Attaragalla and Palukadawela Tanks in the Mi Oya Diversion Scheme.
Data
Tank
Catchment area 66 sq. miles Length of Tank Bund 3500ft,
Tank Full:
Storage 4200 acre feet Head of water 12 ft. Area of water spread 500 acres Spills:
Nature Masonry Rock Length Y 500ft,200ft、
Sluices:
Location R.B. L.B. Size 12” dia. 36” dia.
Irrigation Supply
The work provides direct supply to 833 acres of rice cultivation and feeds Attaragollewa Tank, in the chain.
353

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MI OYA DIVERSION SCHEME
95.1.2 ATTARAGALLA TANK
Location
About 3 miles east off Ambanpola. Co-ordinates F123 (11.1 x 5.5)
Restoration
Restored in 1954, to serve as an intermediate tank in the Mi Oya Diversion Scheme chain to convey Mi Oya flow (diverted by Abakola Wewa) to Palukadawela Tank and for direct supply to fields.
Data
Tank
Source of Supply:
Inlet channel from Abakola Wewa and 16 sq. miles of catchment. Length of Tank Bund 1 miles
Tank Full: -
Storage 3700 acre feet Head of water 15ft。 Area of water spread 500 acres Spills:
Nature Masonry Location R.B. Length 170ft。
Sluices:
Location L.B. R.B. Size 36" dia. 12" dia.
Imlet channel from Abako la Wewa:
Length 5280ft, Bed width 40 ft.
Irrigation Supply
The work serves as intermediate storage and also effects supply to 1000 acres of direct irrigation to new colonization development.
354

MI OYA DIVERSION SCHEMIE
95.1.3 PALUKA DAWELA TANK
Location .
About 3 miles north east of Ambanpola.
Co-ordinates F123 (11.2X6.8)
Scheme
Improved and augmented in 1960 to receive diverted supply from Mi Oya, f om Abakola Wewa, through Attaragalla Tank, forming the end tank of the Mi Oya Diversion Scheme.
Data
Tank
Source of Supply:
Inlet channel from Attaragalla Tank and 7 sq. miles of catchment.
Length of Tank Bund 3800 ft. rank Full:
Storage 5700 acre fit. l lead of water 15ft。 Arca of water spread 650 acres Spills:
Nature Concrete-skin type Location L.B. Length ,100ft, . Sluices: .
Location Central R.B. Size 12" dia. 36" dia. Inlet channel from Attaragalla Tank:
Length 4200 ft. Bed width 35ft,
lrrigation Supply
An extent of 3000 acres are supplied with irrigation water aiding new colonization.
355 .

Page 223
95.2 GALGAMUWA WEWA
Location
About 13 miles east of Galgamuwa Station.
) Co-ordinates F118 (11.5x1.6)
Restoration
Present tank was completed in 1877. The site has historical references.
Data
Tank
Catchment area 4 sq mis. Length of Tank Bund 1200 ft.
Tank Full:
Storage 6500 acre ft. Head of water 20ft。 Area of water spread 640 acres
Spills:
Nature Rock Location R.B. Length 20 ft.
Sluices:
Location - R.B. Size - 18” dia.
Irrigation Supply
Work aids in the development of 400 acres for rice cultivation. W−
Note: This Tank is not to be mistaken for the small railway tank of the same name adjoining the Railway Station.
356

953 MAA ANDARAWA. TANK
Location
Situated east north east of Maha Nanneriya a village 9 miles east of Galgamuwa.
Co-ordinates F118 (2.2X3.1)
Historical
An ancient work.
Scheme
Impounds the flow in Nanneri Oya.
Data
Tank
Catchment area 13 sq miles Length of Tank Bund 4800 ft.
Tank Full:
Storage 700 acre feet Head of water 11 ft. y Area of water spread 315 acres
Spills:
Nature Concrete Structure Location L.B. Length 272ft,
Sluices:
Location L.B. Size S. 2" dia.
Irrigation Supply m
The work benefits 400 acres of rice cultivation for new colonization development.
Approximate cost Rs. 6 lakhs.
357

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95.4 MEDYAWA WEWA
Location
About 4 miles north of Maho-3 miles east of 32nd mile on Kurunegala-Anuradhapura Road.
Co-ordinates F123 (11.0x2.7)
Restoration
Present tank completed in 1879.
Data
Tank
Catchment area 11 sq. miles Length of Tank Bund - One mile
Tank Full:
Storage 2500 acre feet Head of water 14ft, Area of water spread 380 acres Spills:
Nature Masonry and channel flow Location 4 Spills of total Length length 250 ft. Sluices:
Location L.B. Size 12" dia.
Irrigation Supply
Work benefits about 1000 acres of rice fields.
358

95.5 MAHA US WEWA
Location
About 8 miles north east of Anamaduwa, which is on the Kurunegala-Puttalam Road.
Co-ordinates F122 (11.7x6.4)
Restoration
The restoration of this work commenced in 1877 and was completed in 1894 at a cost of Rs. 61,392.
Data
Tank
Catchment area ' 323 sq miles Length of Tank Bund 230 ft.
Tank Full:
Storage 2740 acre fit. . Head of water 16 ft. Area of water spread 525 acres Spills;
No. 1 No. 2 Nitre A Masonry Masonry location L.B. H.L. Length 361 ft. 64ft。
Sluices:
Location R.B.
Size ・26”×18”
Irrigation Supply
A channel system, over 3 miles in length, delivers supply to 875 acres for development of rice cultivation.
359

Page 225
95.6 KOTTUKACHCHIYA AND KACHCHIMADUWA TANKS
Location
At Kottukachchiya, 43rd mile on the Kurunegala-Puttalam Road.
Co-ordinates F122 (1.3 x 7.6)
Kottukachchiya tank and Kachchimaduwa tank across the road are now interconnected by a free passage beneath thi roadway and function as one scheme.
Scheme
Present tank restored in 1950.
Data
Tank
Catchment area 23 sq miles and 95 sq. miles Length of Tank Bund 3400ft。 and 3000 ft. Tank Full:
Storage 2700 acre ft. and 650 acre ft. Head of water 13 ft. and 12 ft. Area of water spread 450 acres and 140 acres Spills:
Nature Concrete Concrete Location L.B. L.B. Length 140ft,200ft, Sluices:
Location L.B. R.B. Size 2 ' X 1 "-6” l 5 ins dia.
Irrigation Supply
Channel system nearly four miles long, supplies 857 acres of rice cultivation by colonists.
This tank functions along with and is augmented by storage and supply from Kachchimaduwa Tank, across the road.
360

95.7 PAHARYA TANK
location
Branch off northwards near 14 miles on the Puttalam Anuradhapura Road and proceed about 3 miles.
Co-ordinates F112 (4.6 x 1.95) .
Restoration
Restored 1957-62.
Scheme
Impounds the flow of Dangaha Ella.
Data Tank
Catchment area 13. Sq. miles Length of Tank Bund mile
Tank Full:
Storage 1800 acre ft. Head of water 16 ft. Area of water spread 250 acres Spills:
Nature On rock Location L.B. Length - 280ft.
Sluices:
Location R.B. Size 30” dia.
Irrigation Supply
The work aids rice cultivation in 350 acres of newly developed
land.
36

Page 226
958 TABBOWA WEWA
Location
About 2 miles north east of 8 M.P. on the PuttalamAnuradhapura Road.
Co-ordinates F/17 (1.1 x 7.3)
Restoration
Restoration of present work, was commenced in October 1912 (Estimated total Rs. 374,700), river closure was effected and work completed in 1925 and on 8.12.25 tank spilled for the first time. The work was improved and enlarged in 1969.
Scheme
Impounds the flow in Nanneri Oya, which is also dammed at Maha Andra Wewa, about 15 miles higher. The spill flows
reach Mi Oya.
Data
Tank
Catchment area 150 sq. miles Length of Tank Bund 1 miles Tank Full:
Storage 12,000 acre ft. Head of water 16 ft. Area of water spread 1500 acres. Spills:
Nature Concrete with Radial Gates 20 of
23'-7”×3'-0 Location L.B. Length 500ft。
Sluices:
Location L.B Central R.B. Size Masonry 12" dia. Masonry
Sluice pipe Arch
Sluice
irrigation Supply
A left bank channel system 33 miles long and a right bank channel system two miles long irrigate in all 2000 acres for rice cultivation.
362

98. RATHAMBALA OYA BASIN
The Rathambala Oya is a small river which empties into the
Mundel lake, near Battulu Oya. Katupotha Tank is an ancient work which has since been restored.
363

Page 227
: 98.1 KATUPOTHATANK
Location
About 6 miles south east of 63 mile post on ColomboPuttalam Road.
Co-ordinates III (11.3 x 0.5)
Restoration
Restored 1952-56.
Scheme
Impounds the waters of Rathambala Oya.
Data
Tank
Catchment area 70 sq miles Length of Tank Bund 1 miles Tank Full:
Storage 3300 acre ft. Head of water 11 ft. Area of water spread 600 acres Spills:
Nature Skin Type Location L.B. Length 350ft。
Sluices:
Location R.B. Size 2'-6" dia.
Irrigation Supply
A 2 mile long main channel with distributaries etc., supply 500 acres of newly developed rice fields by the colonists.
* .364

99.' DE DURU OYA BASIN .
Deduru Oya has its source in the foothills of Matale and flows 87 miles through the Kurunegala and Chilaw Districts and reaches the sea north of Chilaw.
The Deduru Oya basin is one of the three river basins which is situated and receive benefit from more than one monsoona zone. The upper reaches, about 576 sq. miles are situated in the intermediate zone of Matale area and the lower 446 sq. miles are - in the dry zone of Chilaw District.
It has been assessed that the Oya receives a flow of 968,000 acre feet during the Maha season; in addition 254,000 acre feet is received during the Yala season, being the benefit of the south-west monsoonal precipitation in the catchment.
Land Use
Unlike the dry zone river basins, land use in the Deduru Oya basin does not depend on stored irrigation supply. In the upper reaches some rice cultivation is practised with the aid of Irrigation supply from diversion anicuts or diversion anicuts cum storage tanks. There are also a few minor tanks in the catchment.
The basin is generally well developed with coconut plantation, which forms the bulk of agricultural activity in the region.
Proposals for development m
Two major reservoirs are proposed to conserve the flow in the Deduru Oya. The Ridi Bendi Ela reservoir being larger and situated higher could supply water to the Mi Oya basin as well. The lower reservoir would aid the development of lands in the Chilaw District.
As mentioned under Mi Oya Basin, the combined project would aid the development of 50,000 acres.
365

Page 228
99.1 DEDURU OYA SCHEME
In the upper reaches of the Deduru Oya, the river is diverted by a massive masonry anicut to feed Batalagoda Tank.
History records the damming of Deduru Oya at three other places lower down, by Parakrama Bahu I, during his earlier period when he was engaged in the development of Dakkinadesar:
1. “Kotthabaddha' dam, very likely Senegal oya.
2. “Ebavalapitiya” dam-above the Ridi Bendi Ela
anicut. ܫ
3. “Demodera” anicut where Hakwatunu oya and Kim
bulvana oya meet.
But the present Deduru Oya anicut, at Batalagoda, in the upper reaches is a later effort for augmenting Batalagoda Tank, when irrigation development was enlarged under the scheme.
* Deduru Oya works was designed by H. Parker, Irrigation Assistant
and constructed under his guidance, approx. initial expenditure Rs. 526,550.
366

DE DURU OYA SCHEME
99.1.1 DE DURU OYA ANCUT
Location
About 5 miles south of 66th mile on Kurunegala-Dambula Road.
Co-ordinates 114 (10 x 4.4)
Schemeż
Present work completed in 1902.
Data
Anicut Diversion
Catchment area 80 sq miles Length of Structure 275ft, Height 10ft。
Massive masonry structure with three silt gates each 4 ft. wide by 5ft. high.
Head Sluice Y
Location R.B. 6 No. openings Size 6 ft. high 3'-6" wide, each.
Inlet channel to Batalagoda
Length 2 miles Bed width 16ft。
Irrigation Supply
The inlet channel also serves 250 acres direct besides feeding Batalagoda Tank.
367.

Page 229
DE DURU OYA SCHEME
: 99.1.2 BATALAGODATANK
Location ... i About 2 miles south of 66th mile on Kurunegala-Dambulla
Road.
Co-ordinates II14 (8.8 x 5.9)
Historical
Believed to be a very ancient work, constructed to serve the Parana Nuwara City, and repaired by King Kumara Das (513-522 A.C.) and later by Queen Kalyanawathie (12021208 A.C.).
Restoration
Restoration was undertaken in 1890. Present tank completed in 1902.
Data
Tank
Source of supply: Inlet channel from Deduru Oya Anicut and self catchment 5 sq. miles.
Length of Tank Bund 4400 ft.
Tank Full:
Storage 5000 acre feet Head of water 12ft。 Area of water spread 700 acres
Spills:
Nature Concrete Structure Location L.B. L. B. 2 Length 100 ft. 150 ft.
Sluices:
No. of openings 6 Size Each 6 ft. high by 2'-3" wide.
Irrigation Supply
Ten mile long main channel system feeds Dolukanda, Tatirigama, Uyangalla and Hiripitiya branch channels for irrigating in all 5000 acres of rice cultivation.
368

*臨
99.1.2 BATA IAGO DA TANK --SPL
99.2 HAKWATUNU OYA RESERVOIR-SPILL UNDER CONST.

Page 230
99.3 KIMBULWANA TANK
99.4 WANARA WEWA
 
 

99.2 HAKWATUNU OYA RESERVOIR
Location
Sited about four miles east of the 15th mile on the Ibbaga
muwa-Maho Rd., which takes off from near 62nd mile on the Kurunegala-Dambulla Road.
Co-ordinates I/4 (8.5 x 4.0)
Historical
The Hakwatunu Oya (Sankamadhamandu Nadi) tributary
of the Deduru Oya had been dammed and diverted for irrig
ation supply in the ancient days, apparently at more than one site, in this locality.
Scheme
Reservoir formed by impounding the flow in Hakwatunu Oya, by damming a narrow valley between two hillocks Kepi'Yigala and Koragahahena. Construction commenced 1957. Approximate cost Rs. 10 million.
Data
Tank
Catchment area 24 sq miles Length of Tank Bund 2900 ft. Tank Full:
Storage 16,000 acre ft. (nett) Head of water 26 ft. Area of water spread 960 acres
Spills: -
Nature Mass concrete Location Central Length , 200' Segmental concrete structure over 26 ft. high with 3 radial gates 20' x 12' each. Sluices:
Location R.B. L.B. Size 2/3' 6" di 2/3' 6" b
lrrigation Supply
left Bank Scheme 7 miles long benefits 2000 acres of private land and colonization development. Right Bank scheme similarly benefits 1500 acres.
369

Page 231
99.3 KIMBULWANA TANIK
Location
Situated about 4 miles north of the 72nd mile post on the Kurunegala-Dambulla Road, near Lenawa Group Estate.
Co-ordinates I/9 (9.9 x 4.5)
Scheme
Storage reservoir formed by the restoration of an ancient tank impounding the waters of Kimbulwana Oya, a tributary of Deduru Oya.
Data
Tank
Catchment area 38 sq miles Length of Tank Bund 2600 ft.
Tank Full:
Storage 3400 acre feet Head of water 12 ft. Area of water spread 475 acres Spills:
Locations (1) L.B. (2) R.B. Length 100 ft. 100 ft.
Sluices:
Location R.B. Size 3 ft.dia.
Irrigation Supply
The Left Bank Scheme benefits about 215 acres. The Right Bank Scheme, about 2 miles long, benefits 1300 acres.
Development consists of both private and new colonization lands.
370

99.4 WANARA WEWA
Location
In Kurunegala, near Railway Station.
Co-ordinates II 14 (4.3 x 1.3)
Historical
Along with Udu Watta Wewa (Kurunegala Tank) formed
the ancient row of lakes that supplied water to the city of Hastisailapura (Kurunegala).
Restoration
Present tank was completed in 1873 and was improved Subsequently.
Data
Tank
Catchment area 4 sq. miles Length ofTank Bund)o M Tank Full:
Storage 1500 acre feet Head of water 17ft。 Area of water spread 220 acres Spills:
Nature Masonry Location R.B. L.B. Length 40 ft. 28 ft.
Sluices:
Location R.B. L.B. Size 16” dia 12” dia
irrigation Supply
A right bank channel system over a mile long and a two mile left bank channel together benefit an extent of 431 acres of rice cultivation.
371

Page 232
99.5 DIYATURE ANICUT
Location
Near 75th mille on Kurunegala-Dambulla Road.
Co-ordinates 119 (13.5. X 4.7).
Scheme
Anicut Diversion of flow in Kimbulwana Oya a tributary of Deduru Oya. The anicut was constructed in 1937.
Data
Anicut Diversion
Catchment area 12 sq miles Length of Structure 108 ft. Height - 6 ft,
Head Sluices:
Location L.B. R.B.
Size 3'-3”×1”-6" 3”×3'-3"
Irrigation Supply
The left bank channel, 3 miles long irrigates 500 acres. The right bank channel, 23 miles long supplies 300 acres.
372

99.5 DIYATURE ANICUT
99.6 KOSPOTHU OYA ANICUT .

Page 233
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103.1 MURUTHAWELA ANICUT
 
 
 
 
 
 
 

99.6 KOSPOTTHU OYA ANICUT
Location
About 6 miles, as the crow flies to east of Kurunegala is reached by turning northwards at Mawatagama on the Kurunegala-Galagedera Road. -
Co-ordinates II14 (9 x 1.2)
Constructed 1872-90, cost Rs. 12,417.
Scheme
Diversion of flow in Dik Oya, a tributary of Deduru Oya.
Data
Anicut Diversion
Catchment area 42 sq. miles Length of Structure 221 ft. Maximum height 6 ft.
Head Sluice:
Location R.B.
Size 3'-6" x2'
irrigation Supply
Right Bank channel system about 3 mile long benefits 300
CTSS.
373

Page 234
997 RIDI BENDI ELA SCHEME
A project to divert the flow in Deduru Oya, by means of the Ridi Bendi Ela Anicut and convey supply by a long inlet channel, irrigating about 500 acres en route, to Magalle Wewa in Nikaweratiya on which depends over 5000 acres of rice cultivation for water supply for double cropping each year.
Historical
Parakrama Bahu (l 153-1186 A. C.) is recorded to have commenced this work, for the development of Panduvas Nuwara, by conveying Deduru Oya flow to Magalle Wewa. Project consisted of the amicut across the oya and a long channel.
The present inlet channel from anicut to Magalle Wewa was restored in 1942. A channel over 12 miles long, 21 ft. wide, with a road by the side, crossing the Padeniya-Anuradhapura Road near 21 M.P., conveys the diverted flow.
374

RO BEND ELA SCHEME
99.7.1 RD BENOI ELA ANICUT
Location
About 1 miles east of 21st mile post on Padeniya-Anuradhapura Road.
Co-ordinates I/3 (9.6 x 1.1)
Historical
Ancient work, recorded to have been constructed by Parakrama Bahu (1 153-1186) in his earlier period when he was engaged in the development of Panduvas Nuwara to augment supply to Magalle Wewa.
Restoration ــــــــ
Present anicut completed in 1952.
Scheme
Diversion of flow in Deduru Oya, into an inlet channel to feed Magalle Wewa.
Data
Anicut
Catchment area 530 sq miles. Structure 350ft,
Mass concrete with scour gates and
divided wall. - Abutments 20 ft. higher than anicut
CreSt. Head Sluice: w
Location At L.B. Of concrete blocks with a
central pier and two cast iron gates with winch lifting gear.
Openings: 2 NoS. each 10 ft. X3 ft.
375

Page 235
RDI BENDI ELA SCHEME
99.7.2 MAGALLE WEWA—-NKAWERATIYA
Location
At Nikaweratiya. Co-ordinates I/3 (0.8 x 1.9)
Historical
Constructed during the reign of King Maha Sena (276-303 A.D.), later repaired and enlarged, when Ridi Bendi channel and anicut was constructed by Parakrama Bahu (1 153-1186).
Restoration
Present tank was restored in 1873 and improved and augmented in 1958
Scheme
Storage tank which receives in addition to flow from own
catchment, copious supply from the Ridi Bendi Elaanicut by diversion of flow in Deduru Oya.
Data Tank
Source of Supply:
Inlet channel from Ridi Bendi Ela anicut and self catchment 21 sq miles.
Length of Tank Bund 1 mile Tank Full:
Storage - 7500 acre fit. Head of water 18ft。 Area of water spread 650 acres Spills:
Nature Masonry Masonry Location L.B.No. 1 L.B. No. 2 Length 110 ft. 200ft。 Sluices:
Location L.B. Central R.B. l. R.B. 2
Size 24" dia 15" dia. 4" dia. 24" dia.
hirrigation Supply
The left bank channel system, about 3 miles long benefits lands in Magallegama village. The central sluice irrigates lands in Nikaweratiya. The right bank channel system is very long over 14 miles in length and covers an extensive
area west and northwards. In all 5000 acres are irrigated from this work.
376

99.8 VA KADA POTHIA MAHA WEVA
Location
In Nikaweratiya area, about 3 miles south of 22 mile post on Kurunegala-Nikaweratiya Road.
Co-ordinates 18 (0.4x7.4)
Restoration
As the tank had been long out of function, rice and garden cultivation and dwellings are found in the tank bed area. The people have to be re-settled before restoration could be completed.
Scheme
Storage tank impounds flow in Rambukkan Oya—a small tributary of Deduru Oya.
Data
Tank
Catchment area 343 sq miles Length of Tank Bund 3400 ft.
Tank Full:
Storage 3200 acre feet Head of water 10 ft. Area of water spread 505 acres
Spills:
Nature Skin type concrete structure Location R.B. Length 300ft,
Sluices:
Location L.B. R. B. Size 24" d. 24" is
Irrigation Supply
Target for irrigation supply 1000 acres.
377

Page 236
99.9 GALKSSA BEMMA ANICUT
Location
About a mile north of 32nd mile on Madampe-Kuliyapitiya Road.
Co-ordinates I/12 (0.5X2.8)
Scheme
The Dandagamu Oya has been dammed by relief labour and a concrete structure is now provided with spill gates etc.
Data
Diversion Anicut
Catchment area 189 sq. mls. Length of Structure 100ft。 With 8 No. openings each 5' X 11 (Screw operated gates) Height 12ft,
Also a spilling section 36 ft long.
Irrigation Supply
Eight pipe sluices sizes 15" dia. to 6" dia. would aid supply to 217 acres of private developed rice fields and aid in new development of over 50 acres.
378

99.10 KARAWTA YODE ELA
Location
About half mile north of the 103 M.P. on the ChilawKurunegala Road.
Co-ordinates I/7 (1.7 x 1.5)
Historical
An ancient work which conveyed the waters of Deduru Oya to feed several minor tanks.
Restoration
Work on present anicut commenced in 1956.
Scheme
Diversion of flow in Kolamunu Oya, a tributary of Deduru Oya.
Data
Anicut
Catchment area 158 sq miles Length of Structure 177ft。 Openings: 10 NoS. .
Fitted with radial gates of size 15 ft. wide by 8 ft. Head Sluice:
Location L.B. Size 2 openings each
4'-6”×2".
Irrigation Supply
A long ancient channel, over eight miles in length, has now been restored to feed 550 acres in Godawela, 120 acres in Mahawilattawa, 30 acres in Kanattawa etc., and 700 acres in Karawita, making in all a total of 1400 acres.
379

Page 237
100. KARAMBALAN OYA BASIN
The Karambalan Oya is a short stream about twenty five miles long, which, rising in the Kuliyapitiya region, reaches the sea south of Chilaw.
The basin is 230 sq. miles in area and is computed to carry a flow of about 300,000 acre feet.
The high land is all developed with coconut; some rice cultivation is practised in the isolated valleys. These are served with irrigation supply from diversion anicuts.
The area is well developed with highland crops. Almost the entire run off flows to the sea.
380

100.1 ANICUT ACROSS KADUPTYA OYA
Location
About half mile above Tinipitiwewa tank.
Scheme
To divert flow in Kadupitiya Oya a tributary of Karambalan Oya, into Tinipitiwewa, constructed in 1904.
Data
Апісшt
Length of Structure 150 ft. Openings: 5 Nos. each 25 ft wide Head of water 6 ft. 9 inches. Inlet sluice to tank- Planked regulator
3 bays 4 ft. X5 ft.
381

Page 238
100.2 TNP TWEWA
Location
Adjoins 42nd mile on Colombo-Chilaw Road. Co-ordinates I/11 (7.7 x 1.5)
Restoration
Present tank was restored in 1871 and later improved and enlarged in 1939.
Data
Tank
Receives diverted supply from anicut across Kadupitiya Oya and also drainage from own catchment area of
3 sq. miles.
Length of Tank Bund. mile Tank Full:
Storage 500 acre ft. Head of water 7ft。 Area of water spread 200 acres Spills:
Nature Masonry-Circular, C.O. Location R.B. by road side. Length 100ft, Sluices:
Location R.B. Size 2 bay planked regulator 2 X2' Irrigation Supply
The tank supplies irrigation facilities to 960 acres of rice fields.
382

102. MAHA OYA BASIN
The Maha Oya is one of the major rivers of Ceylon. Rising in the Kandy-Nawalapitiya area, the Maha Oya flows for 78 miles through the Kegalle and Negombo Districts, reaching the sea north of Negombo.
The Maha Oya basin is situated entirely in the wet zone and is 590 sq. miles in extent. The total annual run off in the Oya is assessed as being one and a half million acre feet. This is received in about equal quantities during the Maha and Yala seasons.
The basin is well developed with coconut, rubber and other crops of the wet zone. Some rice cultivation is also practised in isolated valleys with the aid of small diversion anicuts.
Computations show that about a million acre feet annually flow into the sea, to waste, unused and therefore plenty of surplus water is available for development
383

Page 239
102.1 YAKA BENDİ ELA SCHEME
Location
Across Maha Oya, about 3 miles down-stream of the Road Bridge at Giriulla.
Co-ordinates II22 (12.1 x8.)
A massive anicut is said to have existed across Maha Oya, about 12 miles below the Giriulla road bridge, which diverted water supply along a long channel, traces of which are seen to-day, for irrigation in Pitigal Korale.
A concrete anicut is envisaged at the same rocky site, about 300 ft. long, 23 ft. high and with eleven radial gates, each 25 ft. by 16 ft. high incorporated in it, to dam the Maha Oya which drains 453 sq. miles of catchment at this spot.
A right bank channel about 20 miles long following the ancient course, wherever now possible, would convey supply for rice cultivation in the drainage basins of Mahandura Oya, Kandapola Oya and the Ratmale Oya assessed at 8000 acres of double cropping.
Approximate cost Rs. 25 million.
384

103. ATTANAGALLA OYA BASIN
Attanagalla Oya Basin is situated between the Kelani and Maha Oya Basins in the Western Province and is approximately 30 miles long by 20 miles wide.
The three streams (1) Diyella Oya (2) Attanagalla Oya and the (3) Uruwal Oya form the Attanagalla Oya which discharges into the Negombo Lagoon as Dandugam Oya and also through Ja-Ela.
Diyella Oya, with a catchment area of 55 sq. miles, crosses the Colombo-Kandy Road, in its upper reaches in the 28th mile near Pasyala. Among the permanentanicuts built across it, for irrigation purposes, are (1) Muruthawela Anicut (2) Pallewela Anicut (3) Maha Amuna Anicut (4) Panugala Anicut and (5) Idallawela Anicut.
The Diyella Oya has its confluence with Attanagalla Oya at Gampaha.
Attanagalla Oya, with a catchment area of 238 sq. miles crosses the Colombo-Kandy Road in the 19th mile. Among the permanent anicuts constructed across it are (1) Morenna Anicut (2) Kitawela Anicut (3) Tammita Anicut and (4) Kotagoda Anicut. The Attanagalla Oya, known as Dandugam Oya in the lower reaches crosses the Colombo-Negombo Road near the 16th mile.
Uruwal Oya, with a catchment area 63.5 sq. miles, forms the Southern basin. The Kinigama, Galwetiya, Bogampitiya and Wellikada anicuts are constructed across it. The Uruwal Oya exits through Ja-Ela but discharges also through Dandugam Oya.
The Attanagalla Oya Irrigation Development Scheme, consisting of the various anicut diversion projects mentioned above was constructed during 1945-1950, and provides irrigation and drainage facilities to over seven thousand acres of land for rice production. Each anicut project is considered in detail in the pages that follow.
385

Page 240
ATTANAGALLA OYA SCHEME
103.1 MURUTHAWELA ANCUT SCHEME
Location
Along Colombo-Kandy Main Road after passing culvert No. 2814 turn left. The anicut is situated here. Nearest Town Nittambuwa 3 miles Nearest Railway Station Pallewela 5 miles Co-ordinates L13 (0.1 x 7. )
Scheme
There used to be 6 temporary amunas built by cultivators
to provide Irrigation facilities to their fields. These Amunas
were very easily washed away for minor floods. As a result the cultivators had to face recurrent heavy losses.
A new permanent structure was constructed in 1955 with 3 No. planked bays and spillway 15 feet wide. The gates are operated by screw lifting arrangement. The two channels originate from the L.B. and R.B. head sluices each having an opening of 2 diameter.
Data
Anicut Diversion
Catchment of Oya 8 sq. miles Length of Structure 427-0" Maximum Height 18'-6" Planked Bays 3 Nos. Head Sluice 2 Nos. on L.B. and
R.B.
Irrigation Supply
386
A total length of over 9 miles of main channels and necessary branch channels provide irrigation supply to 675 acres.

ATTANAGALLA OYA SCHEME
103.2 PALLEWELA ANCUT
Location
By railway line, about a mile north of the Pallewela Railway Station.
Co-ordinates 122 (1.8 x 0.5)
Scheme
Diversion of flow in Diyella Oya. .
Data
Anicut Diversion ܗܝ
Catchment area l8 sq miles Openings: 3 of 6'X5
2 of 6' x2' 3 of 6' x 1" Sluices:
Location L.B. R.B. Size 18" dia. 18" dia.
irrigation Supply
The work benefits 675 acres.
387

Page 241
ATTANAGALLA OYA SCHEME
103.3 MAHA AMUNA ANICUT SCHEME
Location
From Veyangoda-Nittambuwa Road turn left at Pattalagedera and proceed to Kumbaloluwa Sub-Post Office. Turn left proceed mile.
Co-ordinates L12 (10.7 x 7.6)
Scheme
There used to be 16 temporary amunas built by the cultivators to provide irrigation facilities for 275 acres. After every flood these had to be repaired.
A new permanent structure was constructed in 1951 with 6 planked bays the gates of which are operated by screw lifting
arrangements.
Data
Anicut Diversion
Catchment of Oya 24 sq miles Length of Structure 47'-4" Maximum Height 177-07 Planked Bays 6 Nos. r Head Sluice 2 Nos. R. B. and L. B.
Irrigation Supply
An R.B. and L.B. channel system, of total length about 4 miles, benefit 470 acres.
388

ATTANAGALLA OYA SCHEME
03.4 PANUGALA ANCUT SCHEME
Location
From Veyangoda Railway Station along Kalagedihena Road for about 4 mile, turn right and proceed mile.
Co-ordinates L12 (8.95 X 5.40)
Scheme
There had been 10 temporary amunas built by the cultivators to provide irrigation for 625 acres. These were built placing logs across the Oya. Cultivators had to repair them regularly as they were washed away for even minor floods. One permanent anicut was erected to replace them.
Data
Anicut Diversion
Length of Structure 607-6" Maximum Height 6'-0" Planked Bays 4 Nos. Head Sluice 2 Nos. L.B. and R.B.
Irrigation Supply
An R.B. and L.B. channel system of total length about 4 miles, benefit 470 acres.
389

Page 242
AT"TANAGALLA OYA SCHEME
103.5 DALLAWELA ANICUT SCHEME
Location
Along Gampaha-Minuwangoda Road for about 1 mile turn right at the Sign Board and proceed mile to anicut site. w
Co-ordinates L12 (4.9 x 2.5)
Scheme
There had been 4 temporary amunas put up by cultivators to irrigate a total of 244 acres. Occasional floods had washed off these amunas and the cultivators had much difficulty in building them anew. A permanent structure was constructed in 1946 with 5 planked bays operated by screw lifting arrangement.
Anicut Diversion
Data
Catchment of Oya 53 sq miles Length of Structure 42'-6" Maximum Height 9'-6" Planked Bays 5 NoS. each 6' X4“ . . Head Sluice S. No. on the R.B.
| No. on the L.B.
Irrigation Supply
390
A channel system about 4 miles long on R.B. benefits 520 acres. The one mile long left bank channel irrigates 50 acres.

ATTANAGALLA OYA SCHEME
103.6 MORENNA ANCUT
Location
in Colombo District, is situated about 4 miles from Gampaha, about 300 yards to the north of bridge No. 2011 on the Colombo-Kandy Main Road.
Co-ordinates L12 (7.7 X 2.0)
Scheme
There had been 9 temporary amunas, erected by cultivators to head up and divert the flow in this branch of Attanagalla
Oya to aid irrigation of rice fields. In 1948 one permanent concrete anicut structure was erected instead.
Data
Amicut -
Stream Catchment 7 sq. miles Length of Anicut Structure 54 ft. Maximum Height 99 11 ft. Planked Bays 6 Nos. completed with screw lifting
arrangements. Sluices L.B. and R. B.
Irrigation Supply
With over 4 miles of main channels and 6 miles of branch channels, in the right bank and left bank channel systems 1070 acres of private rice fields are irrigated far double cropping.
39

Page 243
ATTANAGALLA OYA SCHEME
103.7 KITAWELA ANICUT SCHEME
Location
Scheme
Along Gampaha-Yakkala P. W. D. Road for about mile, turn to left at Sign Board to the V. C. (gravel) road and proceed to Ihalagama Temple premises. From here proceed on foot to Railroad 300 yards to anicut.
Co-ordinates L12 (5.35X2.25)
There had been 16 temporary amunas built by the cultivators to irrigate a total of 1,318 acres. The cultivators had to face difficult times whenever there were floods.
Instead, in 1948 two permanent anicuts were constructed, a 4 Bay anicut and the other a 3 Bay anicut. The gates of these anicuts are operated by screw lifting arrangement.
Anicut Diversion
Data -
Catchment of Oya 75 sq miles Length of Structure (No. 1) 33'-4" (No. 2) 24'-3" Planked Bays (No. 1) 4 Nos. (No. 2) 3 Nos. Maximum Height (No. 1) 13'-7" (No. 2) 12'-0 Head Sluice 2 Nos. on L.B. and R.B. ,
Irrigation Supply
392
A channel system, with 3 miles of main channels and 8 miles of distributary channels, provide irrigation supply to 1450 acres.

ATTANGALLA OYA SCHEME
1693.8 TAMMTA ANICUT
Location
Near 15th mile on Ja-Ela-Gampaha Road.
Co-ordinates L/2 (2.0 x 1.8)
Scheme
Diversion of flow in Attanagalla Oya.
Data
Amicut
Catchment area 138 sq miles Length of Anicuts No. 1 No. 2 V 24ft。 32ft,
3 bays 6' x 11' 4 bays 6' x8 Sluices:
Location L.B. R.B. Size 8." 3'x4'
Irrigation Supply
The R. B. channel 1 miles long irrigates 300 acres: the L.B. commands 30 acres.
393

Page 244
ATTANAGALLA OYA SCHEME
103.9 KOTAGODA ANICUT
(GALWETIYA)
Location
Off the l6 mile post on the Gampaha-Ja-Ela Road. Co-ordinates L12 (0.1 X 2.8)
Scheme
Diversion of flow in Attanagalla Oya.
Data
Anicut Diversion
Catchment area 143 sq miles Length of Structure 33ft。 Openings: 4 Nos. each 6” x 11'-6" SJuices:
Location L.B. R.B.
Size 3 of 9” dia. 3 of 9” dia.
394

ATTANAGALLA OYA SCHEME
103.10 KINIGAMA ANICUT
Location
About half mille east of Miriswatte Junction, off 17th mille. Colombo-Kandy Road.
Co-ordinates L/7 (6.5 x 8.5)
Scheme
Diversion of flow in Uruwal Oya.
Data
Anicut Diversion
Catchment area 12 sq. miles Length of Anicut 45 ft. 3 No. bays 3'-6”×6"
Irrigation Supply
The left bank channel system nearly 3 miles long irrigates 270 acres. The right bank channel over 3 miles in length benefits 255 acces
395

Page 245
ATTANAGALLA OYA SCHEME .
103.11 GALWETTYA ANCUT
Near 16 mile post on Colombo-Kandy Road. Co-ordinates L/7 (5.8 x 0.02)
Scheme
Diversion of flow in Uruwal Oya.
Data
Anicut
Catchment area 16 se. milles Length of Structure 38 ft. Openings: No. 5" x 5'-6"
5 NoS. 5 " X 5'-6" Sluices:
Location R.B. Size ' x 3" planked
irrigation Supply
Work benefits 142 acres.
396

ATTANAGALLA OYA SCHEME
103.12 BOGAMPTYA ANCUT
Location
About a mile north of Ganemulla.
Co-ordinates L12 (2.4 x 0.7)
Scheme
Anicut diversion across Uruwal Oya.
Data
Anicut Diversion
Catchment area 30. sq. miles Length of Structure 40 ft. ܫ Planked Bays 6 No. each 8' x 5'
Sluices:
Location - L.B. R.B. Size 18 ”9×”18 ܫ" two rows.
Irrigation Supply
A left bank and right bank channel system convey water
to 160 acres.
397

Page 246
ATTANAGALLA OYA SCHEME 103.13. WELIKADA ANICUT
Location
Along Gampaha-Ja-Ela P. W. D. Road for 33 miles, turn
left at Mabima cemetery and proceed along road for mile to anicut site. s
Co-ordinates L12 (0.5 x 1.9)
Scheme
There had been 15 No. temporary amunas irrigating a total of 570 acres before a new permanent structure was built. The temporary structures erected by the cultivators were
washed away whenever there were floods.
The new structure was constructed in 1946, and had 5 planked bays operated with screw lifting arrangements.
In June 1957 repairs were effected to R.B. Guide Bund which was affected by floods.
Data
Amicut Diversion
Catchment of Oya 39 miles Length of Structure 78'-9" (inclusive of Abutments) Maximum Height 7'-0" Planked Bays 5 Nos. Head Sluice Two NoS. R.B. and L.B.
Irrigation Supply
An R.B. and L.B. channel system, of total length 7 miles irrigates over 1230 acres.
398

CHAPTER 4 PRољстs UNDER CONSIDERATION 1 MAHAWELI GANGA SCHEME
1.1 DVERSION ANCUT AT POLGOLLA
A Location
The site is by the road-side, about five miles from Kandy on the Wattegama Road.
Project
To divert a portion of the flow in the Mahaweli Ganga and convey same through Sudu Ganga to (1) Kala Wewa Basin (2) Moragahakanda Reservoir and (3) generate hydroelectric power.
Proposed Data
Diversion Weir
Length of weir (at top level) 530 ft, Maximum height 49”ft, Operating head of water 7”ft, Elevation of water level 1445 M.S.L. :
Spillways
Vertical lift hook type 10/40'x 20'
Diversion Tunnel
18 ft. diameter tunnel 26100 ft. long would convey 2000 cusecs of water for irrigation and power generation.
Power Generation
4 units of 9.0 M. W. each Mean annual energy 237 m.K.W.h.
Approximate Cost
RS. 97.44 milion.
399

Page 247
12 MORAGAHAKANDA RESERvoy
Location
Is situated on the Naula-Elahera Road abot a mile above the Elahera anicut.
Project
Reservoir to regulate the flow in Amban Ganga, and the
diverted flow from Mahaweli Ganga, for irrigation & power generation.
Reservoir
Proposed Data
Source of Supply:
Ambanganga catchment, also balance of Mahaweli Ganga flow (part) diverted at Polgolla through Sudu Ganga and after diversion at Bowatenne.
Length of Reservoir Dam consists of:
Earthen embankment 2,020 ft. Earth & rock fill dam 1,200 ft. Concrete dam 1,620 ft. Total length 4,840 ft.
Reservoir Full:
Storage 600,000 acre feet Normal Elevation-water spread 630 M.S.L, Minimum Elevation 567 M.S.L. Regulated yield 1.318,000 acre feet Active Storage 455,200 acre feet
Spillway:
Sector gates 3/65' x 5'
Channels and Irrigation System:
The N.C.P.Canal & augmenting supply to systems D.G.
Power Generation
Four units of 10 M.W. each. Mean Annual energy 96 K.W.h.
Est. Cost (1967)
Rs. 186.6 million
400

1.3 VECTORIA RESERVOR
Location
Is situated across the Mahaweli Ganga, at Victoria Falls, somewhat below the confluence of Hulu Ganga tributary; the site is reached from the 12th mile Kandy-Teldeniya Road, by driving for six miles through estate roads and
getting across the Hulu Ganga.
Project
The main purpose of this reservoir is to regulate the Mahaweli flow for power generation and irrigation.
Reservoir
Proposed Data Source of Supply:
Mahaweli Ganga Catchment area 730 sq miles Length (at top level) of concrete Dam 1400 feet. Maximum height of Dam 338 feet Cubic contents (concrete) Dam 681,000 cyds
Reservoir Full:
Storage capacity 415,000 ی acre feet
Operational Status:
Normal water surface Elevation 1410 M.S.L. Minimum . 1215 , Active Storage 390,000 acre feet Regulated yield 926,000 acre feet
Spillway:
Four Segmental gates 4/50' x 30"
Under-sluices:
Two Size-25 ft. by 25 ft.
Power Supply:
Static head 660 ft. Pressure tunnel (diameter) 21 ft. Length w 4,720 ft. Discharge (Max) 2740 cusecs
Power Generation
Installed Capacity - 4/30 M.W. Mean power output . 629,000 K.W.h.
Approx. Cost
Rs. 247.2 million.
40

Page 248
1.4 RANDENGALA RESERVOR
Location
is sited across the Mahaweli Ganga, at Randenigala Hills, about five miles above Minipe anicut, which is about ten miles drive from Mahiyangana.
Project
This main reservoir regulates the flow in the Mahaweli Ganga for irrigation, power generation and flood control.
Reservoir
Proposed Data
Source of Supply:
Mahaweli Ganga Catchment area 900.5 sq. mls.
Length
Along crest of concrete dam 1705 feet
Maximum height of dam 279 feet
Cubic contents of dam 1,200,000 c. yds.
Reservoir Full:
Storage capacity 629,000 ac. ft.
Operational Status
Normal water surface elevation 750 M.S.L.
Minimum -do - 672 M.S.L.
Active Storage 374,000 acre ft.
Regulated yield
90% frequency 1,462,000 ac. ft.
Spillway
Sector gates 3/70"×25'
Power Generation ་་”
Installed Capacity 3/25 M.W. Mean power output 370,000 K.W.h.
402

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Page 249
2. MALWATTU OYA RESERVOR
Location
The Dam site is at the village of Kappachchi and is reached by an access road taking off from the MedawachchiyaMannar Road near the 40th mile post.
Scheme
A reservor to impound the flow in Malwattu Oya.
Proposed Data
Tank
Catchment area 8 19 sq miles Length of Tank Bund 2.42 miles Maximum height - 92.5ft,
Tank Full:
Storage 282,000 acre ft.
Head of water 23ft。
Area of water spread 5,300 acres
Spills:
Nature - Mass Concrete
Location L.B.
Length 217 ft. with 5 No. Radial Gates
39' x 20' high
Crest Elevation 87.3 M.S.L.
Sluices:
Location L.B. R.B.
Size 8' x 6 6'-6" X6'-6"
Irrigation Supply
Target 32,000 acres including 20,000 acres of existing fields, and generation of 800 K. W. of electric power.
404

3. SAMANALA WEWA
Location
Impounding the flow in the upper reaches of Walawe Ganga. The dam site is reached from off Belihul Oya on BalangodaHaputale Road and the tunnel sites etc. is easier reached from of the Balangoda-Kaltota Road.
Scheme
The proposal is to construct a main dam across the Walawe Ganga below its confluence with Belihul Oya, thus forming a large storage reservoir. The stored water is to be led through a two mile long tunnel into a smaller reservoir to be erected across the Diyawini Oya (called the Forebay reservoir, elevation about 1500); from here water will drop about a 1000 ft. into Katupai reservoir to be constructed across Katupai Oya. Hydro electric current will be generated and water will be issued for irrigation development from Katupai
reservoir.
Proposed Data
Main Dam
Catchment area l32 sq. miles Length of Tank Bund 1665ft。 Maximum height of dan 353ft,
Tank Full:
Storage 265,000 acre ft. Head of water 54ft, Area of water spread 2,740 acres Spill:
Nature Concrete (El. 1524) Length 220ft.
Draw off to Diyawinne Tank
10 ft. dia. tunnel at El. 1470.
Power Generation
Four 30,000 K.W. units to be installed and expected to generate 350 million K.W. of electric at energy.
Irrigation Development
40,000 acres,
Probable Cost
Rs. 260 million.
405

Page 250
4. KELAN GANGA BASIN SCHEME
Flood Control and Water Potential Utilization
The Kelani Ganga conveys the drainage of 890 sq. miles from Adam's Peak to the sea in Colombo.
A scheme for ""Flood Control and Utilization of Water Potential of the Kelani Ganga Basin with the view to Flood Protection Development of Power and Irrigation' has been drawn up by U. S. S. R. Technopromexport of Moscow in 1961.
The proposals include:
1. Embankments
By raising the existing embankments and providing gh embankments from Pugoda to river mouth, the Kelani a is to be made capable of discharging increased flood flow of 115,000 cusecs, as against the 57,000 cusecs only which can now be discharged by the river.
2. Storage Reservoirs
(a) Nawata-Parusella Reservoir will be constructed by short high dams across the Kelani Ganga at Nawata and across We Oya. at Parusella. The reservoir thus formed would accommodate, 718,000 acre ft. of basin drainage and besides regulation of flood would generate electricity-33 M.W.
(b) Holombuwa Reservoir is formed by earth dam across the Gurugoda Oya at Holombuwa and would hold 62,000 acre ft.
(c) Diversion canal-50 miles of conveyance canal of 2430 cusecs capacity is to be constructed for transbasin diversion of the Kelani water to the dry zone regions of the North Western Province for the development of 146,500 acres of new lands. 9 Pumping Stations are to provide liftirrigation for 80,000 acres of rice cultivation.
Probable Cost
Rs. 922 million.
406

5. DE DURU OYA RESERVOR
Location
The reservoir embankment is sited about 1000 ft. above the Ridi Bendi Ela Anicut across the Deduru Oya.
Co-ordinates I/3 (9.75x 1.05)
Scheme
A reservoir Scheme impounding the Waters of Deduru Oya to benefit 33,000 acres of existing lands.
Proposed Data
Tank
Catchment area 530 sq miles Length of Tank Bund 5500ft,
Tank Full:
Storage 50,000 ac. ft. Head of water 57ft,
Spills:
Nature Radia Gates of 32 x 25 Location L.B. Length 42'
Suice:
Location R.B. Size 2 Nos. 4 '0 X 4 '0 Sill Level 178 M.S.L.
Pumping Plant
Part of the sluice discharge is expected to be lifted across the ridge to the neighbouring basin.
Total Capacity 325 cusecs No. of Pumps &
Type 4 Nos. Vertical — Mixed flow
Horse power of each 1275
Designed head 84
Maximum power req.4,000
Size of delivery 2 Nos. pipe lines 5' 0 each.
Irrigation Supply
To benefit 33,000 acres of existing lands.
407

Page 251

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Page 252
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Numbers in the above map refer to names of works as appearing in
index pages 408-414
 
 
 
 
 
 
 
 
 
 
 
 

NDEX OF DEVELOPMENT WORKS IN MAJOR REVER BASNS
No. Nanne Page
i. Abakola Wewa A - ... 353 2. Adachchal Kulam s 。ア - ... 186 3. Akathimurippu Channel KO KO ~ • A ... 334 4. Akkarrayan Kulam A. A a- ... 292 5. Akkaravita M. F.P.S. - - - - - * KO KO 50 6. Alahena Tank - a- - a ... 76 7. Alawakkai . . . . . . . ... 332 8. Aligalge Tank w w8 a - ... 66 9. Allai Scheme O NO KI> ! (* » - AO X 0 ... 251 10, Allai Scheme-Alai Tank ... A X XO - a 253 11. Allai Scheme Verugal Hd. Wiks. - a ... 252 12. Ambagaha Ela Amuna O O « ... 108 13. Ambalam Oya Tank a- a a A 6 KM ... 159 14. Ambalaperumal Kulam a . . . ... 295 15. Ambatalenpahala MFPS A KI. a & K O KO 49 6. Ambewela Reservoir & 8 a . ... 208 17. Amparai Tank ... & 8 - m ... 169 18. Anaisuddakaddu Kulam - KM 0 ... 199 19. Andankulam - - - O KO a ... 259 20. Andella Oya Tank 8 . A --- a m ... 79 21. Andupelena Anicut KO A V & 98 22. Anga medila Anicut w a в в « " ... 246 23. Angamuwa Tank ... - a ... 350 24. Arachchi Amuna ... - - a- - - * • KR- KO • 92 25. Aralaganwilla Wewa » «X- XA- ... 194 26. Attalbage Oya Anicut 4 XX - - ea w ... 211 27. Attanagalla Oya Scheme a XA XA 00 a ... 387 28, Attaragollawa Anicut a a 0 ... 240 29. Attaragalla Wewa as a ... 3S4 30. Attidiya Dr. & S. W. E. S. ... - a C- A 59
31. Badagiriya Tank - - - «X «6 » ... 121 32. Badulu Oya Anicut Ka a KO O O O O V- ... 230 33. Badulupitiya Ela KO KO - - - - ... 228 34. Balagalla Tank ... a a , , ... 180 35. Balaharuwa Tank... 25 ... - مچو مه 36. Bassawakkulama ... Qa «6 AA - - - - - - .321 . ه 37. Batalagoda Tank ... a - XO XO - ... 368 38. Batatuhena Anicut A XA AT - ... .227 39. Bathmedila Ella ... A VA XO ... 226 40. Batugedera Anicut - O KI> & W & - a 63 41. Bogahaduwa Amicut - - a a w 75 42. Bogampitiya Anicut KO O ... 397 43. Bolgoda F. P. S. - - - 60 44. Bomiriya M. F. P. S. . - X • a KOM O 4* 50 45. Buttala Anicut ... a a - ... . 138 46. Bowetenne Anicut A» «O «6 a- a - ... 238
47. Castlereagh Reservoir O 4- 9 O XO O w as - 43 48. Chadayantalawa Tank - - ... 172 49. Chamalankulam Tank a a ... 268 50. Chandrika Wewa ... KM 4 KO «» ... 12 51. Chemamadu NA WA KA a 0 0 ... 284 52. Cheddikulam a O KO KO ... 328 53. Colombo North F. P. S. a- a «» v 0 a - - - 52 54. Colombo South F. P. S. A II - «Y KO A A W 53 55. Colombo South Dr. Scheme ... A - 54

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No. Navre Page
56. Dambarawa Tank 23 57. Dambe Wewa 12658. Dambutulu Wewa 247 59. Damme Ela - 64 60. Dandeniya Tank 84 61. Debera Wewa ... 29 62. Dedduwa Dr. S. W. E. S. 69 63. Deduru Oya Scheme 366 64. Deduru Oya Amicut 367 65. Denegama Tank 93 66. Dewahuwa Tank ... 34 67. Dikiliyadde Ela 220 68. Diulwewa 274 69. Diyature Anicut 372 70. Diyawinne Maha Ela 04 7). Ekgal Aru Tank ... 75 72. Elahera Canal . 239 73. Elephant Pass L. S. 289 74. Ellagala Anicut 28 75. Ellawela Tank 83 76. Embilipitiya Tank 110 77. Ethandamurippu Tank 264 78. Ethpitiya Anicut 92 79. Ettimole Wewa 45
80. Gal Amuna Anicut 248 81. Galkissa Bemma 378 82. Galgamuwa Wewa 356 83. Galimetiyawa Tank 257 84. Gal Oya Anicut 62 85. Gall Oya Scheme 63 86. Gal Oya Left Bank Scheme 164 87. Gal Oya Rt. Bank Scheme ... 73 88. Gallitude-Kindelpitiya SWES 61 89. Galwetiya Anicut ... • − �h 396 90. Gal Wewa 195 91. Gampolawela Raja Ela 212 92. Ginganga MFPS ... 76 93. Giant's Tank 333 94. Giant's Tank Scheme 33 95. Giant's Tank Headworks 33 96. Giant's Tank Inlet Chl. 332 97. Giant's Tank Akathi Chl. 334 98, Giritale Tank 24 99. Giridara MFPS. ... 51 100. Gomarankadawela Wewa 265 101. Goiyapana Dr. & SWES 80 02. Habarana Wewa ... 270 03. Hakuruwela Anicut 98 104. Hakwatunu Oya Wewa 369 105. Hali Ella Tank ... 82. 06. Hallala Dola Anicut 79 107. Hambeganuwa Tank 06 108. Hambumandiya Anicut 92 109. Handapanagala Tank 24 1 10. Hattota Amuna ... 234 111. Hennita MFPS 50

No. Nane Page
112. Hewagamuwa MFPS. 49 113. Hikkaduwa PF. Dr. S. 73 114. Himidurawa Tank... 167 115. Hingura Ara Tank 109 116. Horiwila Tank ... 271 Il 17. Hulanda Oya Anicut 142 1 18. Hurulu Wewa 272
119. Idallawela Anicut ... 390 120. Ihala Kalan Kuttiya Tank 348 121. Ilakanthai Kulam 254 122. Illukachchenal Tank 16 123. Irakkamam Tank ... 178 124. Iranaimadu Kuliam 286 125. Iratperiya Kulam 325 126. Jaffna Peninsula Lagoon Scheme 287
127. Kadawera Tank ... 117 128. Kaddukamunai Tank 84 129. Kaddumurippu Kulam 202 130. Kahawatte Anicut... 92 131. Kalatuwawa Reservoir 47 132. Kala Weva 342 133. Kala Wewa Scheme 342 134. Kala Wewa Yode Ela 344 135. Kalmadu Kulam J 282 136. Kalmadu Kulam V O − − 306 137. Kaluaggala-Berendi Gampala MIFPS 50 138. Kalutara S.F.P.S. ... - 67 139. Kanagarayan Kulam 285 140. Kandalama Tank . 340 141. Kande Ela Tank ... 209 142. Kantalai Tank 255 143. Kanukerni Tank ... 278 144. Karadiyan Aru Tank 191 145. Karaugahawela Wewa 236 . 146. Karawita Yode Ela w w a 379 147. Karawila Tank ... a 139 148. Kariyalai Nagapaduwan Tank 298 149. Kavijjapitiya SWES so 70 150. Kattiyawa Tank ... - « 345 151. Katupath Oya Anicut 103 152. Katupotha Wewa ... 364 153. Kaudulla Tank 245 154. Keenawela Ela ... 222 155. Kekanadure Tank 87 156. Kelani Ganga MFPSS so 49 157. Kelani Ganga Basin Scheme ... 406 158. Kelani Ganga Water Supply Scheme 48 159. Keulkada Wewa ... -- 273 160. Kimbulwana Oya Wewa 370 161. Kinigama Anicut 395 162. Kirama Oya Scheme 90 163, Kirama Oya Basin Anicut 92 164. Kirama Oya Tank 91 165. Kirimachchi Kulam 200 166. Kirindi Oya Scheme 27 67. Kirindi Oya Head Works 128

Page 254
No. Nanne Page
168. Kirindi Oya Left Bank 129 169. Kirindi Oya Right Bank 33. 70. Kitawela Anicut ... 392 171. Kitulabokke Anicut
172. Kitulpe Ela 27 173. Kitul Wewa a■ « w 190. 174. Koddai Kaddina Kulan 294 75, Kondavattuvan Tank 68 176. Kongaha Wewa ... 36 177. Kospothu Oya Anicut 373 178. Kotagoda Anicut ... 394 179. Kotiyagala Maha Wewa 46 80. Kottukachchiya Tank 360 181. Kumbukkan Oya Anicht 4.
82. Kumana Tank 43 83. Kurai Tank 309
84. Labugama Reservoir 46 185. Lahugala Tank 49 186. Laksapana Power Station 44 187. Lemasuriyagama Anicut 29 88. Liyangahatota Anicut 3.
189. Madampe Dr. & SWES 72 90. Medawachchiya Kulam 266191. Madu Ganga Dr. & SWES 7
192. Madukande Tank 302
193. Ma Ela • • ❖፡ 216. 194. Magalle Wewa 376 195. Maha Amuna Anicut 388
196. Maha Andarawa Tank 357 197. Maha Eliya Anicut 224 198. Maha Gal Wewa ... 20 199. Maha rampai Kulam 305 200. Maha Kandarawa Tank , 322 201. Maha Oya Anicut... ... saw 235. 202. Mahatotilla Oya Anicut - 225
203. Mahaweli Ganga Basin Development 203
204. Mahaweli Ganga Diversion Project 399 205. Maha Wewa - - - 19
206. Maha Willachchiya Tank 336 2007. Mana US Wewa 359 208. Malayadi Tank 17ד" 209. Malwattu Oya Project 404 210, Mamadole Tank 4. 211. Mamaduwa Tank ... 304 212. Manankatiyawa ... 36, 213. Manalpiddi Aru Scheme 183. 214. Maniar Kulam ... 327
215. Mapakada Wewa . 232 216. Maruthamadu ... 329. 27. Maruthankerni Tank 20
218. Mawakulam w 250 219. Mediawachchiya Tan 324 220. Mediyawa Tank 358. 221, Minimaru MFPS 5
222. Minipe Yode Ela 22 223. Minneriya Scheme 242 224. Minneriya Tank 242

No. NWarne Page
225. Minneriya Yode Ela 243 226. Minneriya-Kantalai Yode Ela 244 227. Mi Oya Diversion Scheme 352 228. Moderagam Aru Anicut 337 229. Mousakelle Reservoir 4. 230. Mora Ela MFPS ... 50 23. Moragahakanda Project 400 232. Morenna Anicut ... 391 233. Mora Wewa 263 234. Muhathan Kulam... 330 235. Murapola Ela 214 236. Murihandy Tank ... 291 237. Muruthawela Anicut 386 238. Muruthawela Project 99 239. Muthuliyankaddukulam 279 240. Muthurajawela Scheme 55 24. Nachchaduwa Tank 317 242. Nagodawetiya Regulator 88 243. Nalanda Oya Reservoir 237 244. Namal Oya Tank 165 245. Naula Tank 151 246. Navalkiri Aru Reservoir 18 247. Neelapanikan Kulam 267 248. Neethai Tank 160 249. Nickawela MFPS 51 250. Nilavarai Pumping Scheme 290 251. Nilwala Ganga MFFS 89 252. Norton Dam ... 44 253. Nuwara Wewa 319
254. Okawela Anicut 92 255. Oluwila Tank 115
256. Padawiya Tank 276 257. Pahariya Tank ... 36 258. Pahuru Oya MFPS 50 259. Palatota Basin MFPS 67 260. Palavi Tank - - - 307 26. Pallang Oya Tank 174 262. Pallewela Anicut ... 387 263. Palukadawela Tank 355 264. Pannalagama Reservoir 156 265. Panama Tank 147 266. Panankamam Tank 308 267. Pannagamuwa Tank 133 268. Panugala Anicut ... - - - 389 269. Paraduwa-Diyagama MFPS 65 270. Parakrama Samudra Scheme ... 246 271. Parakrama Head Works 246 272. Parakrama Topawewa etc. 247 273. Paravipanchan Tank 258 274. Pattiyawela Anicut 92 275. Pattiyapola Maha Wewa 98) 276. Pattivila MFPS . 50 277. Pavatkulam 326 278. Periya Elumpurikki Kulam 261 279. Periyakulam 260 280. Periyamadu 313

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44
Usgala Siyambalangamuwa Tank
No. Name Page 281. Periyapandivirichchan 31 282. Periyathampani Kulam 310 283. Polgolla Diversion 399 284. Polwatte Ganga Regulator 78 285. Pugoda MFPS ... 5. 286. Puluganavi Tank ... 183 287. Punani Anicut 197 288. Radella Tank - 150 289. Randenigala Reservoir 402 290. Rajangana Tank ... 349 291, Ranala MFPS 50. 292. Ranna Anicut - A 98 293. Ridi Bendi Ela Scheme 374. 294. Ridi Bendi Ela Anicut 375 295. Ridiyagama Tank ... 116 296. Rottakulam 8 A 152 297. Rottuwakulam 249 298. Rufus Kulam 155 299. Rugam Tank 189: 300. Sagamam Tank ... 158 301. Samanala Wewa Project 40S 302. Sangilikandarawa Tank 323 303. Sapugoda Anicut 85 304. Senanayake Samudra 163 305. Siyambalangamuwa Tank 346 306. Sorabora Wewa . 233 307. South Lagoon (JPLS) 288 . 308. Sudupanawela Anicut 123 309. Tabbowa Tank ... 362 310. Thachchana Maruthamadu 312 311. Taldema Ela - - - 229 312. Talwatte MFPS. ... 50 313. Tammita Anicut ... 393 314. Tangalu Welyaya SWES 94
315. Tekkam a 33 316. Tenniyankulam 297 317. Thannimurippu Kullam 277 318. Tharawai Kulam ... 192 319. Thondai Mannar Barrage 287 320. Thumpankerni Tank 182
321. Tissa Wewa (in A’pura) 320 322. Tissa Wewa (in Tissa) 130 323. Topawewa 247 324. Uda Deberawa, Amicut 92 325. Uda Walawe Reservoir 105 326. Udayar Kaddu Kulam 280 327. Udugoda Bandara Ela 213 328. Udukiriwela Amicut 97 329. Uggal Kaltota Scheme 102 330. Uma Ela 223 331. Unichchai Tank 187 332. Urapola Anicut 86 333. Urubokke IDam a 96. 334. . Urubokke Udukiriwela Tank ... 97 醬 Urubokke Diversion Anicuts ... 336.

Page
Nane
337. Vadamarachchi Lagoon 287 338. Vakaneri Scheme 198 339. Vakaneri Tank ... 198 340. Valathipiddy Tank 170 341. Vammiyadi Tank 57 342. Vanmerikulam 296 343. Vavunikulam 300 344. Vavuniya Tank 303 345. Veeragoda Tank 7 346. Vendarasan Kulam 256 347. Verugal Head Works 252 348. Visuwamadu Tank 28 349. Viyadikulam . 338
350. Wadamune Wewa 96 351. Waduwawela Ela 28 352. Waggala Modera SWES 7ך 353. Wakumulla Anicut - 98 354. Walawe Scheme (Lower reaches) 13 355. Walawe Scheme Head Works ... 13 356. Walawe Left Bank Scheme 16 357. Walawe Rt. Bank Scheme 114 358. Wanara Wewa 371 359. Weerapitiya Maha Ela 215 360. Welgamuwa MFPS 50 361. Welligaha Kandiya Tank 88 362. Welikada Anicut ... 398 363. Wellikada. Ela 210 364 Welliwita MFPS 49 365. Wellawa Anicut ... 107 366. Wimalasurendra Power House 43 367. Wirawila Tank . 34
368. Yabaruwela MIFPS 50 369. Yakabendi Ela ... 384 370. Yakada Potha Maha Wewa 377 37. Yoda Wewa 13
72. Yudaganawa Tank 37
45

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