President Gotabaya Rajapaksa has instructed officials of state agencies and stakeholders to accelerate construction work on irrigation projects. The World Bank, Asian Development Bank Green Climate Fund, the Japanese International Corporation Agency and donor countries provide financial support to most of these development projects. Among mega irrigational development projects are the lower Malwathuoya multi-sector development project and the Uma Oya multipurpose development project.
The Uma Oya multi-purpose development project and the lower Malwathuoya multi-sector development project are a turning point in recent irrigation history. The Malwathuoya project construction which was proposed in 1959 by a team of Russian experts has been dragging on for nearly 60 years until President Gotabaya Rajapaksa intervened to realisethe lower Malwathu Oya reservoir benefitting Sinhalese, Tamil and Muslim communities in Anuradhapura, Mannar and Vauniya districts.
Apart from providing drinking water, irrigational and industrial water, the project will generate electricity of 4.38 Gigawatt hours per annum. The Uma Oya multi-purpose development project will also provide drinking water, irrigational and industrial water including the generation of hydro electricity. The Uma Oya Down Stream Development will revive the prosperity and splendour once prevailed in historic Wellassa opening a new era for farmers in the Kirindi Oya river basin.
Headwork construction
The headwork construction of the Anuradhapura lower Malwathuoya multi-sector development project commenced in March 2021. The main dam under construction across the Malwathuoya at Bogoda village close to the Thanthirimale scared area, is three kilometres in length. The water capacity of the reservoir is 169,000 acre feet. The cost to be incurred for the completion of the reservoir is Rs. 39,000 million.
Once the project completed in 2024, around 45,000 acres in the the Anuradhapura and Mannar districts will get irrigational water in the Yala and Maha cultivation seasons.The annual water extraction requirement for drinking water from the reservoir with the consideration of future expansion in North Central and North regions under National Water Supply and Drainage Board will be 27.1 MCM.
Simultaneously, the Uma Oya multi-purpose development project (UOMDP) implemented by the Irrigation Ministry is planned to divert water from the Uma Oya basing to Kirindioya basing through a trans-basin tunnel to be used for hydro power generation and for supplementing the irrigation sector requirements in Badulla, Moneragala and Hambantota districts. Under this project two roller compacted concrete dams are constructed across two tributaries of Uma Oya to create separate reservoirs namely Puhulpola and Dyraaba reservoirs which are linked through a link tunnel.
The projects contract price is US $ 514 million. Uma Oya multipurpose development project consists of the construction of two dams across the two main tributaries of Uma Oya such as Dulgolla Oya at Puhulpola and Mahatotilla Oya at Dyraaba. There are over 23km long tunnels namely the link tunnel, headrace tunnel, vertical tunnel, vertical pressure shaft, tailrace tunnel with an underground power station at Randeniya.
Among the main objectives of the UOMDP are the annual trans – basin diversion 145 MCM water from the Uma oya basin to Kirindi Oya basin, generating and supplying 230 GWh of country’s national grid, provision of irrigation to 4500 hectares new and 1500 hectares existing lands, providing 30 MCM drinking and industrial water in Monaragala and Hambantota district.
Contract
The contract for this project was based on an unsolicited proposal submitted by Farab Energy and Water projects of Iran and Farab International FZE, to the Government and upon extensive negotiations between the parties concerned a contract agreement was signed in April 2008 between Irrigation Ministry and the Farab Energy and water projects of Iran and Farab International FZE collectively with a 5-year contract period plus one year maintenance period. It has been agreed that the commencement date of the project is March 15, 2010 whereas targeted project completion shall be May 2022 with room for an extension.
As far as the civil work pertaining to the UOMDP, the height of dams such as 38m Puhulpola and Dirraba 42.5 meters. The length of the reservoirs link tunnel is 3750 m whereas the Headrace (Power) tunnel length stands at 15.54 km. The length of the tailrace tunnel is 3650 meters.
According to the Irrigation Ministry information sources the water being collected in the two reservoirs is diverted to an underground powerhouse with capacity of 120 megawatt generating up to 230 GWh annually through a headrace tunnel beginning from its intake in Dyraaba reservoir with a length of 15.2 km. After utilising for power generation the water (145 million MCM per annum) then discharged to Aikota Ara a tributary of the Kirindi Oya through a tail race tunnel which is to be used for irrigation, drinking and industrial purpose.
Hydro power
The Uma Oya Multi – Purpose Development project consisting of the construction of two dams, across two main tributaries of Uma Oya at Welimada and Dyraba and in a 23 km long trans – basin diversion tunnels with an underground power station at Randeniya. The objectives are the generation of hydro power, irrigation, provision of drinking water and water required for industries. In particular the major concern is to supply adequate water for the utilisation at second International Air – Port at Hambantota, the Hambantota industrial zone the Hambantota harbour and oil Refinery.
As far as the origin of the project proposal the UOMPD project was first proposed in 1991 more than 30 years ago. However, when it was initially proposed it was rejected based on protests such as that it would harm the rights of the people to free water and due to some technical flaws in the master plan of the project. The agreement on UOMDP finalised in 2008 and the Iranian President Mahamoud Adminejad and former President Mahinda Rajapaksa witnessed signing the agreement.
After the signing the agreement, civil society organisations community leaders clergy including leading bhikkus held a number of protesting campaigns against the project highlighting some of the adverse impact. The villagers in the area protested vehemently claiming that the project’s underground tunnels would dry up many freshwater springs creating a acute shortage of water. In December 2014 cracks were observed in houses in Heeloya, Palleperuwa, Makulella, Egodagama, Weheragalathenna caused by the vibrations of tunnel construction.
Leak
Consequently, the Central Environmental Authority had detected a leak pouring out 250 liters of water per second in to the underground tunnel systems of the Uma oya Multi – proposes Development project. In 2015, the first part of the UOMDP had been completed and under the agitative circumstances like continuous public protests, the then Government of Maithripala Sirisena suspended the project following the appointment of a committee to submit a report on controversial impacts on the project. However, the Central Environmental Committee declared after investigations that the project contractors had violated a number of environmental assessment committee conditions for causing such unwarranted incidents.
Environmentalists said that a flawed environmental impact assessment for the first phase was passed in 2011 under Government pressure. The Centre of Environmental Justice such as CEA, put forward its objections, over the first EIA in 2011, alleging that the environmental cost has not been analysed properly and if the cost of resettlement was included too the project wouldn’t yield any benefits. The project is a part of the development policies carried out by the Sri Lanka government.
As in many other huge development projects in this particular project seemed causing socio – economic losses, displacement and pollution affecting the livelihoods of people for the profits of national and international elites. A huge amount of material and energy have been used to create the facilities. Following environmentalists and local authorities there has been also a lack of transparency in the implementation of the project.
It is unfortunate that due to the agitation of villagers in the UOMDP project area including the discovery of the leak pouring water in to underground tunnels, cracks in the households due to vibrations caused in the process of tunnel construction the construction which was in progress of the UOMDP halted nearly for two years. Although later action was taken to overcome the problematic situation, it is reported that water still leaks at a smaller level, and Iranian engineers and staffers are still engaged in the project activities.
A senior engineer of the UOMDP told the Sunday Observer that the electricity generation will commence most probably in June 2022, following the testings expected to be started in May.
Kirindi Oya basin
The Uma Oya Downstream Development project is the other major component of the Uma Oya multipurpose Development project which mainly includes the multi development in Kirindi Oya river basin.
The main objective of this project is to use the water resources of Uma oya and Mahatotilla Oya to solve the acute shortage of water being experienced in Kirindi Oya basin in Wellassa region a part from using for the generation of hydro power implemented under the UOMDP. The Irrigation Department had estimated in 2015 that the total cost to be incurred was Rs 9352 million and later in 2021 it was revised as Rs 17,914 Rs million, concerning the Uma oya Down Stream Development Project.
Under this sub component the following items were planned at the beginning to get the maximum benefits such as construction of new AlikotaAra Reservoir in the Kirindioya basin holding a capacity of 5200 acre feet, increasing the capacity of Handapanagala reservoir from 5000 acre feet to 15000 acre feet, construction of new Kuda Oya reservoir with a water capacity of 18500 acre feet and construction of canal systems up to Singhalayagama. Canal system include construction of Alikota – Ara main canal 24 km long, Kudaoya main canal 36 km long and construction of Handapanagala left bank canal eleven km long with Alikota Ara reservoir new 624 hectares and 638 hectares of land getting irrigation facilities in Yala and Maya Seasons while under the emerging Handapanagala reservoir 5620 acres are to be cultivated in Yala and Maha seasons.
Also with new Kudaoya reservoir now under construction 5,250 acres and 2,050 acres of land would able to be cultivated in the Uma Oya Downstream Development project would provide waters to around 110 minor tanks with 55 tank improvements in the region.
Handapanagala reservoir
Under this project on one side the waters stored in Alikota Ara reservoir are released to Kirindi Oya and through the Handapanagala anicut build across the Kirindi Oya water will be diverted to new Handapanagala reservoir. Around 2000 families in Thanamalwila Divisional Secretariat division in Wellawaya are highly benefited from the project. The Irrigation Department in collaboration with the NWSDB is making arrangements to provide drinking water to Kahakurullanpalessa Habbegamuwa and the surrounding areas. Among other benefits for livelihood empowerment are improved facilities for inland fisheries industry, infrastructure development, improving livelihood and health care conditions and ground water recharging.
At present, the Irrigation Department had been endeavoring to complete the construction work of number of irrigation projects country wide. Among them are lower Deduru Oya, Sengal Oya, Morana, Wellassa, Navodaya, irrigation projects, Mahagalgamuwa feeder canal project Mahagona reservoir project, Kawudulla Damsopura extension project Godigamuwa reservoir project Wilakandiya reservoir project Kudawilachchiya and Dematagala reservoir projects. Apart from these large and medium scale irrigation projects the Irrigation Department is entrusted with the Wari Saubhagya (Irrigation prosperity) program involving the complete restoration of 5,000 minor irrigation tanks scattered in the country mainly in the dry zone.