Drought helps expedite renovation work on Kalawewa tank

by Gamini WARUSHAMANA

Renovation work on the Kalawewa tank in the Anuradhapura district with a 100,000 acre feet capacity is now in progress, under the Dam Safety and Water Resources Planning Project (DSWRPP). The prevailing drought in the area has helped to expedite work, especially in the renovation of the riprap of the tank, said the Director, River Valley Development and Reservoirs, H.H. Padmasiri.

Renovation work on the Kalawewa tank is slow due to capacity limitations of the contractors.

The dry weather condition is ideal for renovation work of the dam and we can minimise the economic and social impacts. "Our effort is to complete the laying of rip-rap and dam filling before the monsoon rain starts," Padmasiri said.

The cost of the Kalawewa renovation project is Rs.128 m. Laying a new riprap, dam filling, installation of toe filters, construction of toe drains, bathing places, installation of instruments to measure water level and pressure, renovation of spill gates and sluices are being carried out under the project.

There were cracks in all six sluice gates of the tank and concrete and electro mechanical repairs were done on the spill gates. Eight new safe bathing places have been set up considering the large number of local and foreign tourists who visit the tank throughout the year.

This project will improve water management capabilities and directly benefit the farmer community. Reducing the risk of the dam breaking is another objective of the project. Modern technology will be used to monitor water seepage while upgraded electro mechanical systems of the spill gates will help the authorities to react quickly in case of an emergency, he said.

The Kalawewa tank, built by King Dathusena (455 -473 AD) was expanded by King Mahinda - II (777-797 AD). It was renovated during the British colonial period and in 1958. Mahaweli waters reached Kalawewa in 1976 under phase I of the Mahaweli river development project ending the uncertainty of water for irrigation in the Kalaoya valley.

Today the Kalawewa tank is a key reservoir in the Mahaweli system. This is the first major renovation and rehabilitation of the tank undertaken after 1958. The DSWRPP launched in 2008 had selected 32 major reservoirs for renovation and the project was scheduled to be completed by 2013. However, due to the delay in implementation, it has been extended by two years.

The World Bank has provided an interest free loan of $71.6 m for the project.

The DSWRPP recently organised a media field tour to demonstrate the progress of Kalawewa, Kandalama and Dambuluoya tanks.

Most of the ancient dams dating from a 2,000-year-old irrigation-based civilisation were made of packed earth. Most of them have not undergone any major repair in the recent past. The DSWRPP has found that there are seepages, cracks in the dams and parts of the dams had even sunk.

Spill gates, sluice gates and other safety mechanisms too are in a dilapidated condition and need immediate modernisation.

The objective of the DSWRPP is to ensure public safety and address key challenges faced by the farmers in the country. With the dams getting older it has been found that they suffer from various structural deficiencies.

Renovation work on the Kandalama tank is complete. This is the first sub-project to be completed. The Kandalama tank has a 33,000 acre feet capacity and provides water for farmlands up to Kekirawa.

Engineer Sanjeewa Ilangasinghe of the Mahaweli Authority said that a range of issues related to the irrigation system has been solved and as a result socio economic status of the people will improve.

Dam filling, laying rip-rap, repairs of the sluices and spill gates, toe filters and toe drains, construction of safe bathing places were included in the renovation work of the Kandalama tank.

A new bridge has been constructed over the spillway addressing the transport issues faced by the resi'dents in several villages across the Kandalama dam. During the rainy season these villages are marooned for several days as spill water of the tank goes across the main access road. It affects the livelihoods of the people and the tourist hotels in the area.

This is the first major renovation of the Kandalama tank after 62 years. The cost of the civil construction is Rs. 50 m and the cost of electro-mechanical work is Rs. 70 m, Ilangasinghe said. The renovation work on the Dambuluoya tank too needs similar reconstruction work and in this case too, a substantial part of the sub project has been completed.