Thursday, July 10, 2014

Divert Kelani River to Rajarata

The second week of June should have been an eye opening moment for Sri Lankans. Heavy rains fell on the western slopes of Central Highlands, raising the fear of floods once again. It was just weeks after inclement weather had claimed more than 20 lives. Meanwhile, Rajarata, the agricultural heartland of the island, was still reeling from the effects of a long drought which has dried most tanks and is likely to reduce the rice production significantly this year.
Spilling of Upper Kotmale Dam (Chathuranga Perera,

Sluice gates of the reservoirs in the Kelani River catchment area were opened since water reached spilling levels. However, in stark contrast, water levels were at 20-30 percent of the capacity in the four main reservoirs of the Mahaweli River (Kotmale, Victoria, Randenigala, Rantembe). For example, while the South Western parts of the island were being inundated, power generation was done only for 2 hours in Victoria Hydroelectric Power Plant. (The accompanying table shows the water levels as of June 25).
Water levels in major reservoirs on June 25, 2014.

Furthermore, the Mahaweli Project has been unsuccessful in providing water to the dry zone which is struggling through drought, simply because there is not enough water in the Mahaweli River. The tunnel starting from Polgolla can supply 875 million cubic meters per year to Rajarata. This is equal to four times the capacity of the Kotmale Reservoir. However, only 60 percent of it is supplied due to the lack of water in the Mahaweli River. The months May-September are the dry months in Rajarata. The main objective of the Mahaweli Project was to provide water to Rajarata during this period. However, this year, the said objective has not been achieved.

During the past few years, a significant change of the rain pattern has been observed. It may have been caused by the climate change or some other reason. It has created the possibility of what happened earlier this month from recurring in the near future. A certain area of the country is flooded while another area dries up for lack of water.

Since the weather pattern of the whole country is affected, and it affects the people as a whole, a holistic approach must be taken to solve this problem. One cannot limit to the Mahaweli River or the project. The country should be taken as one unit and solutions should be sought.

A Kelani-Mahaweli tunnel

Although it could appear as a far-fletched idea, there is a possibility of linking Kelani River and the Mahaweli River by a tunnel. If such a link is established, in a situation where Kelani River has more than enough water, the excess can be diverted to the Mahaweli River. It will help flood control in the Kelani River basin and simultaneously will help irrigate Rajarata. Therefore, the water that will possibly inundate the homes and roads in the Kelani valley will be used to cultivate rice which will feed the country. Effectively, the Kelani River will be diverted to Rajarata.

Diverting water from Kelani River might not be possible continuously. If the water level goes down in the Kelani River, salt water might come up the river and even enter the Ambatale Reservoir. Therefore, the diversion should be done according to the water levels of the rivers.

The best place to establish the Kelani-Mahaweli link could be the Ginigathhena area. Although many of us are unaware of the fact, the two rivers are only a few kilometers apart from each other in this area. It is also a famous fact that the rainwater which falls to the roof of the police station in Ginigathhena reaches two rivers. Water falling on one side of the roof reaches the Kelani River while water falling on the other side reaches the Mahaweli. While this writer is no expert in engineering, simple logic gives the thought that this could be done. A feasibility assessment of such a tunnel should be carried out by relevant experts to determine the possibility of such a project from being undertaken.

Dams above Polgolla

Another drawback in the Mahaweli Project is the fact that there are no reservoirs above the Polgolla dam except in Kotmale. However, the Kotmale Dam is in a branch of the Mahaweli River, the Kotmale Oya. The main river has not been dammed above Polgolla. If the river can be dammed in these upper reaches, it will facilitate the storage of water above Polgolla Dam. Thereby, it could be released when needed to Rajarata through Polgolla.

Several aspects have to be considered in studying the possibility of such a project. One factor will be the possible reduction of the electricity generation at Victoria Power Plant. However, this can be compensated by building power plants associated with the reservoirs upstream. Another more sensitive issue will be resettling people. Displaced people should be compensated adequately, perhaps with both monetary and land compensation.


The coming years will be a time of food scarcity and water scarcity. These two are interrelated with each other. Therefore, any government thinking about the future will have to decide on steps to guarantee water and food security to its people.

There is also a moral obligation for the Mahaweli Authority towards the people who were displaced by earlier projects and were resettled in places such as Mahaweli H Zone. They left lands where there was no scarcity of water. Therefore, the authorities should do their best to supply them water for their agricultural needs. It is a moral obligation of the country to a people who sacrificed for the betterment of all.

Diverting Kelani River could be the best answer to the drought in Rajarata. It might be the best answer to the flooding of the lower reaches of the Kelani River basin. It could be the next irrigation revolution Sri Lanka is waiting for.

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