A massive multi-functional project for Deduru Oya

Ariya RUBASINGHE

The Deduru Oya is the sixth largest river in Sri Lanka which is about 142 km in length and has a water resource area of about 2,420 km. The objective of the project was to prevent about 1,000 billion sq. metres of water flowing out to the sea and to be used for productive purposes.

The historical records indicate that during the reign of King Parakramabahu the Great, dams were built at three locations basing the Deduru Oya and the water was used for irrigation purposes.

Construction work of the Deduru Oya project in progress. Pictures by Nissanka Wijeratna

Although preliminary discussions on development activities basing Deduru Oya was held in the 1990s and in 2002, the present government was able to start the massive irrigation project which is currently being implemented. A massive 2.4 km long and 20 metre high dam is now being constructed near Wariyapola.

Project Direct Engineer B. A. A. S. Perera told a group of media personnel who visited the project site that 70 percent of the construction work of this dam has already been completed and the project is scheduled to be completed by 2013. This dam is expected to hold 4,000 cubic acres of water upon its completion.

Our local engineers have been able to achieve the targets set out for this project utilizing the local engineering knowledge in accordance with a local design, using local funds and local manpower. This project which is estimated to cost Rs. 8,000 million is totally funded by local resources. Funds are released for this project annually from the Treasury and the amount that has been allocated for the year 2012 is Rs. 1,800 million.

Over 900 families will be relocated in an area of 1,781 hectares that will go under water due to this project. The resettlement of these families is in its final stage. This reservoir has about 1,400 km of water resources areas and can hold 75 million cubic metres of water.

The Left Canal: The reservoir has eight sluice gates and its Left Canal is about 44 km long. It runs through the electorates of Wariyapola, Nikaweratiya, Panduwasnuwara, Bingiriya. This canal is to feed about 200 small tanks. It is expected to provide irrigation water to about 6,000 acres from this left canal.

The South Canal: The capacity of holding water by the 33 km South Canal is 8.5 cubic metres. It is a completely concreted water flowing canal. This canal runs through Yapahuwa, Nikaweratiya and Anamaduwa Electorates upto Inginimitiya reservoir.

The main objective of this canal is to provide irrigation water to 2,640 hectares of Iginiyamitiya which is facing an acute water shortage problem. From this canal, irrigation water will be provided to another 3,000 hectares land while the Radav Bendi Ela project will provide irrigation water for 400 hectares and the Thabbowa reservoir will provide irrigation water for another 865 hectares.

The Central Canal: The Magalla Central Canal which is 12 km in length is also a canal of special significance under this project. This canal has a water flow of 1.4 cubic metre per second and it passes to Mahawewa through the Nikaweratiya electorate. It is expected to provide irrigation water to the Magalla project from the Central sluice of this canal. It will first feed the hydro power project and then pass to the Magalla project through the Ridee Bendi Ela.

Drinking water: This project will also provide drinking water facilities to about 1.5 million persons belonging to 50,000 families in 14 Divisional Secretariat Divisions.

Flood water management: The Deduru Oya project also aims to undertake flood management, minimize erosion of the reservoir banks and to make the Deduru Oya, a water way which has a continuous high flow of water.

Electricity and other social benefits: As a by-product of this project 1.5 MW of power will be generated. Other benefits that could be accrued from this project is to get a boost for the cultivation of additional crops, coconut etc., development of new village roads and uplifting of the standard of living of people in the areas of Karuwalagaswewa, Kobaigane, Wariyapola, Ganewatte, Mahawa and Maspotha.

The project has so far provided employment for about 500 unskilled workers, trained them in various skilled jobs and has contributed to the flow about one million rupees to the village population. Nearly 15,000 families will directly benefit from this project. In addition, about 200,000 persons will benefit directly and indirectly from this project.

Deduru Oya project

Use of local engineering skills: The construction work of the main dam is being carried under the direct supervision of the Irrigation Department while the digging of canals is being carried out by the Department deploying local contractors.

Physical progress: At present 90 percent of the main dam construction, three percent of the construction of sluices, 90 percent of the left sluice gates, 85 percent of the Southern sluice gates, 10 percent of the Southern canal, 60 percent of the left canal (30 km has been completed from the 44 km), 30 percent of the extension of the Magalle South canal, 50 percent of the estimation and surveying of the canal tributaries have been completed.

Resettlement: Over 2,000 hectares will get inundated by this project. There are about 700 families in these areas. These areas belong to the four Divisional Secretariat Divisions of Maspotha, Ganewatte, Mahawa and Wariyapola.

The people who get displaced due to the Deduru Oya project were given the option of selecting land areas of their own preference for their resettlement. The selection of these lands was carried out by the project officers of the area Land Commissioner and the Divisional Secretaries.

Relief relating to resettlement will be provided to the people in accordance with Cabinet decisions.

These include provision of one acre of inland and one acre of paddy land to the families depending on farming under the Radav Bendi Ela project (for 76 families), and for 77 families that were displaced from the Kobaigane Divisional Secretariat Division provision of one acre land free of charge and another one acre from the same area on concessionary basis from the Thelahera area. In addition to this, to those who prefer to live close to the town, to provide 1/2 acre each from the Peterweli Estate or Polgammana Estate or from Madurakanchiy Estate in Bamunukotuwa. The sub families will get 1/4 acres. All these families will also get compensation for their land that will be acquired by the project.

The targets of this project are: completely filling the Deduru Oya Reservoir with water before the 2012 Maha season, provision of water to the main left canal before the 2012 Maha season, and completion of the construction of the South canal before the end of 2013. In this manner another multi-functional huge irrigation project of Sri Lanka is being constructed for the benefit of the future generations.