Harnessing the Mahaveli – SA Wickramasinghe, 1955
Posted on July 17th, 2023
e-Con e-News
(from ‘Relief of Ceylon’, Chapter V, The Way Ahead)
‘The study of the problem of agriculture & industry necessarily involves the study of the relief of the country before a comprehensive scheme could be intelligently planned for agriculture and industry.
In the centre of the island is the hill country over 1000ft. in elevation. The rest of the country is lowlands or plains which can be subdivided into 3 sections, the South East Plain, the South West Plain and the Northern Plain.
The hill country consists of mountain ranges rising up to 8,000ft. Most of the rivers in Ceylon take their source from this region. The Mahaveli Ganga and its tributaries form the main streams of this region. In this region there are over fifty waterfalls; the main waterfalls are the Aberdeen Laxapana Falls at an elevation of 3,000 ft., the Devon and Ramboda Falls at an elevation of 5,000 ft; and the Diyaluma, Kurunduoya. Manawela and Dunhinda Falls which are some of the more important falls. Only the Aberdeen Laxapana Falls has been harnessed for hydroelectric power so far.
The South West Plain extends from the hill country to the west coast between the Deduru Oya in the North and Walawe Ganga in the South. This plain has the largest and most populated river valley settlements. Except for the Deduru Oya all the rivers have their upper catchment areas in the hill country. The Maha Oya, Kelani Ganga, Kalu Ganga, Gin Ganga are the main rivers. All these rivers in their lower reaches form an extensive flood plains. The Rakwana and Deniyaya Hills are separated from the main hill country by the Kalu Ganga and Walawe Ganga Valleys.
The South East Plain lies between the Walawe Ganga and the Mahaveli Ganga. The Walawe Ganga, Kirindi Ganga, Menik Ganga and Kumbukkan Oya directly drain the hill country in the south.
The Central Region of the coast of the South East Plain is a high plateau extending from the Badulla hill range to almost the eastern sea coast. This region includes the fertile and historic Wellassa region and Buttala Wedirata. The Gal Oya, Heda Oya and other small rivers drain this region to the sea. On either side of this plateau are the plains of the Mahaveli Ganga and some of its tributaries and the basins of Walawe Ganga and Kirindi Ganga.
The central plateau and the flat river valley provide enormous possibilities for water conservation, hydroelectricity and extensive irrigation schemes with diversion of water from one river basin to another.
The East Coast is studded with lagoons, some of which are silted and now cultivated with paddy. By deepening of the rivers and by building a network of canals along the coast, we could easily provide drainage, water transport and irrigation for these low-lying coastal plains extending from Tangalle through Ambalantota, Hambantota, Batticaloa, Trincomalee, and MulIativu right up to the Jaffna lagoon.
Water conservation and diversion of water from one river basin to another, would mean the harnessing of the waters of the Mahaveli Ganga & its tributaries, the Laggal Oya, Badulu Oya, Uma Oya and Kotmale Oya, and the Walawe Ganga, Kirindi Ganga, Menik Ganga and Kumbukkun Oya with the rivers in the Eastern Coast which dry up in the dry seasons, partially or completely. These include Wil Oya, Heda Oya, Karanda Oya, Gal Oya, Andella Oya, Mundori Oya, Maduru Oya, Pankulam Aru, Yan Oya, Moo Oya, and several other streams.
These rivers can be made permanent streams feeding millions of people in this plain. The benefits of such a grand scheme must stir the enthusiasm of every patriotic citizen to unite for the struggle to overthrow this reactionary UNP Government, which shamelessly continues to defend its policy of selection of an uneconomic project for the development of only the lower basin of one river, the Gal Oya, with the help of the US experts at a prohibitive cost.
The Northern Plain extends from the Matale hills in the central region and lies between the Deduru Oya and the Mahaveli Ganga. From the Matale hills in the South the plain slopes away towards the West, Northwest, Northeast and East, thus providing a remarkably favorable natural relief for the diversion of the Mahaveli Ganga through a main canal for irrigation and water transport and for feeding the rivers that flow fanwise from the centre of this plain to the West and East coasts. Such a scheme involves several dams and reservoirs in the middle and upper catchment areas of the Mahaveli and its tributaries, including the Amban Ganga.
Such a scheme can feed all the streams in the Northern Plain that flow westwards and eastwards but now dry up for the greater part of the year. Such a scheme which could be economically developed with Soviet & Chinese technical aid & essential equipment, will be able to irrigate over 3 million acres. Additional advantages will be production of hydroelectric power at points where the water level changes and provision of cheap water transport. We also secure permanent protection of the country from floods and soil erosion by the scientific harnessing of flood waters and protection of the rivers from silting.
The natural relief of our country indicates that the central hilly region which is less than 5,000 square miles or one fifth of the entire country, control the future destiny of our people.
Effective control of all our big rivers can only be carried out by the building of big dams in this region in order to conserve water in big reservoirs. We thereby augment water supply for hydroelectricity and also make it possible to divert water from one basin to another. The numerous waterfalls can only be harnessed to provide maximum hydroelectric power by such a comprehensive scheme for water conservation which will ensure a steady flow of water even in the dry seasons of the year.’