WRD starts work to strengthen Cholavaram reservoir’s bund that bore brunt of intense rains last year

The lake’s bund runs for nearly 3.5 km and has a depth of nearly 7.5 metre. The ₹40-crore project started recently is aimed at improving nearly 1.2-km stretch of the bund. A diaphragm wall, a concrete wall constructed underground, would be provided in the vulnerable portion of 200 metre, to arrest seepage and also function as a water retaining wall

The Cholavaram reservoir, a waterbody in Tiruvallur district, was one of the many sources that bore the brunt of December floods last year. | Photo Credit: FILE PHOTO

Cholavaram reservoir, which was severely affected during intense rain last year, is being restored to prevent seepage during extreme weather events.

Built during the British rule prior to 1877, the waterbody served as a balancing reservoir and a source to store water for city’s drinking water supply. The waterbody in Tiruvallur district was one of the many sources that bore the brunt of December floods last year.

Water had flowed out of the reservoir through the weakened portion of the bund, posing a flood threat to the downstream areas. Temporary measures were taken to alleviate inundation, said officials of the Water Resources Department, which is executing the restoration project.

After many years, the department has begun work to strengthen the vulnerable portions of the lake’s bund and ensure the safety of the waterbody. The reservoir’s storage that has declined to 10% of its capacity of 1,081 million cubic feet was also one of the criteria for initiating the work.

It may be recalled that the reservoir’s weir was strengthened about a decade ago to increase the lake’s capacity by an additional 200 mcft. However, no major work was carried out in the past decade.

The lake’s bund runs for nearly 3.5 km and it has a depth of nearly 7.5 metre. Officials of the WRD said the ₹40-crore project was started recently to improve nearly 1.2-km stretch of the bund. A diaphragm wall, a concrete wall constructed underground, would be provided in the vulnerable portion of 200 metre, to arrest seepage and also function as a water retaining wall.

The remaining stretch of the bund would be stabilised and widened. The entire work would be completed by September, officials said. However, experts noted that the other portions of the bund would also need to be improved for a comprehensive solution.

The department is also surveying the reservoir using differential global positioning system. Officials said the digital survey would ensure accuracy of project implementation and prevent manual errors. It would help understand and monitor the changes along the waterbody.