A massive multi-functional project for Deduru Oya
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.
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.
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
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
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
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.