Agricultural development:

Irrigation sector - a driving force

by P. Krishnaswamy

Sri Lanka has a long history, or rather the longest history of all nations, of having implemented techniques for reservoir construction to regulate water for irrigation for food crop production.

'Hydraulic civilisation' dates back to 400 BC in Sri Lanka when they had constructed the "Bisokutuwa" or the sluice for regulating irrigation.

The kings who ruled the country in the era thereafter and successive governments since independence followed in that tradition, constructing major irrigation systems to provide adequately for the food requirements of the people, without making them to depend on external sources for the purpose.

President Mahinda Rajapaksa when he came to power in 2005 gave first priority to making the country self-sufficient in rice and the country, under his 'Mahinda Chintana' concept, has already achieved it. It is also likely that Sri Lanka will export rice in the near future.

The Irrigation Department set up over a century ago has followed the tradition, implementing several major multipurpose reservoir and irrigation projects from its inception, starting from the massive Galoya Valley and Udawalawa Development Projects under the government of Prime Minister D.S.Senanayake, followed by other projects by successive governments including the Chandrika Wewa Project, Jayanthi Wewa Project and the Lunugamwehara project (Kirindioya), Mahakanagarawa and Rajangana projects. . The Department also played its significant role towards the massive Mahaveli Multi-purpose Development Project which encompasses many parts of the country.

The Department has already implemented several major projects under the ' Mahinda Chintana' concept that : " By 2020, the Irrigation Sector will become the driving force in agriculture development with the supply of water in adequate, equitable and reliable quantities and in a sustainable, efficient and economic-friendly manner".

These development projects in the irrigation and agricultural sector have been well studied, minutely planned and systematically implemented to ensure biodiversity and sustainability , thanks to the vision of our ancient rulers and President Rajapaksa, while water crisis, both for consumption and food crop production, is looming large in many world nations today. In many countries, water diversion from rivers has now reached a point where some of them no longer make it to the4 sea. In some, especially in the Middle East countries, exploitation of below-surface water has been excessive and reckless, without regard for what is sustainable and without any plans for replenishment. As water is taken from agriculture, grain imports in those countries typically rise.

Fortunately Sri Lanka is safeguarded in these respects. The future of the irrigation sector has been set out in a way to promote agriculture productivity by increasing the availability of new water resources and enhancing the present level of waster use and conveyance efficiencies to an optimal level.

Under the 'New Water Resources Development Program' the already started large scale development programs will be expedited, after resolving the technical and financial constrains over the medium term.These include the Moragahakanda & Kaluganga Reservoirs Development Project, the Deduru-oya Reservoir Project, the Uma Oya Hydro Power Diversion Project and the Rambukkan Oya Project. These reservoir projects will also replenish the below-surface aquifers around the project-site areas.

The total investment requirement in the irrigation sector over the period from 2010 to 2020 is estimated at Rs.277.5 Billion. Of this Rs.186.7 Billion is expected from foreign sources and the remainder will be financed by the government with the support of the private sector. The Government has allocated Rs.4.062 Billion in the 2012 Budget for 19 ongoing new irrigation projects. The project-wise breakup and the amount allocated are: The Rambukkan Oya Reservoir Project in Maha Oya Divisional Secretary Division in the Eastern Province which has received the second largest allocation of of Rs.492 Mn under the 2012 budget is targeted to irrigate 1400 ha of new cultivable lands which include 400 ha of high lands.

The Rambukkan Oya river discharges more than 50 MCM water annually to the Indian Ocean through the Mundani Aru river, mainly during the North-East monsoonal season.

This source has been tapped to improve the agricultural productivity and other facilities in the divisional secretary area. More than 2200 agricultural families are directly benefited under this project while more than 25,000 families will get other benefits including drinking water and replenishment of ground water aquifers. The gross storage of reservoir is 56 MCM.

The water spread area is 800 ha and is designed flow is 5.7 m3/sec. Under the canal system, the length of the main canal is 7 km and the length of distributory canals is 39 km . The length of field canals is 84 km .Eight minor tanks will also receive water from the canals .

The catchment area of the reservoir is 128 Sq. km The other benefits include pipe borne water supply to the Maha Oya area and improved road network within the project area. The project will be completed at the end of 2012 . Other infrastructure facilities to the people of the Maha Oya Divisional Secretary division include road networks, electricity, schools and clean drinking water which will largely contribute to the improvement of the quality their life of people.

The Weheragala Reservoir Project ( Menik Ganga Reservoir ) which has received the third highest fund allocation of Rs.400 Mn under the 2012 Budget has already been completed. Its gross storage capacity is 60,000 acre feet.The river water is diverted to the Lunugamvehara Tank and there are multiple benefits under this project, including irrigation facilities to 25,000 acres of paddy land belonging to over 20, 000 agricultural families , drinking water and bathing facilities to people of the area and also to the large number of pilgrims to the Kataragama shrine. Part of the reservoir is located within the wildlife park.

It also helps to protect the flora and fauna and provides water to the wildlife in the sanctuary which attracts a large number of tourists. Various infrastructure facilities have been provided to the areas covered by the project, including road networks, electricity and facilities to grow subsidiary food crops.

It ensures regular release of water to the Manik Ganga during the dry season, greatly benefiting the pilgrims. Under the Ellepothana Project in the Anuradhapura district an anicut has been constructed across the Yan Oya with two canals feeding water to several minor irrigation tanks, benefiting about 1100 agricultural families engaged in paddy cultivation. This being a dry zone the levels of the water tables in the surrounding areas have been elevated providing easy access to drinking water from the ground. In the Kandy district a concrete dam is being constructed across the Gurugal Oya tributary river.

The work is in progress. On completion it will provide irrigation facilities to about 220 acres of paddy land and benefit over 2400 families. The 300 meter concrete dam over the deep river valley will also provide easy access for the people of Hanguranketa to Kandy and vice versa.

The other ongoing projects will also provide infrastructure facilities to the local residents in addition to providing irrigation facilities for the cultivation of paddy and other highland crops.