THIRUVANANTHAPURAM: The persistent and heavy rainfall causing large-scale urban flooding in the capital has reignited the pressing need for the long-delayed cleaning and desilting of the Aruvikkara reservoir. With the reservoir’s reduced holding capacity due to silt and sediment accumulation, authorities are compelled to open the shutters promptly after continuous rainfall, resulting in the overflow of rivers and canals, and subsequent flooding in densely populated urban areas.
The reoccurring inundation of the capital has intensified the call for expediting the long-pending desilting of the reservoir, enabling agencies to respond more effectively to calamities. While previous attempts by the Kerala Water Authority (KWA) to initiate the desilting project were unsuccessful, the state government, in 2019, assigned the Kerala Irrigation Infrastructure Development Corporation (KIIDC) to undertake the desilting of the reservoir through a turnkey basis.
Initially built in the 1930s with an original capacity of two million cubic metres, the Aruvikkara dam’s storage capacity has dwindled by 50% due to accumulated silt and sediments. An official from the city corporation emphasised that the immediate opening of the dam shutters post-rainfall exacerbates urban flooding. Stressing the urgency of desilting and capacity enhancement, the official emphasised the need for increased water retention to delay the need for opening the shutters. “No major desilting work was undertaken at the dam since it was constructed. They need to desilt and increase the capacity so that more water can be contained and delay the raising of shutters,” said the official.
Desiltation work to be tendered within two weeks, says KIIDC According to KIIDC, the detailed project report (DPR) for the deslitation project has been finalised. “We will be tendering the work within two weeks. We are undertaking the project on a turnkey basis so that the government doesn’t have to spend any money. Also, revenue will be generated from the project,” said KIIDC chief executive officer S Thilakan.
He said that around 10 lakh metric cube of accumulated silt, sediments and sand will be removed from the reservoir as part of the project. “Aruvikkara reservoir is the drinking water source of Thiruvananthapuram and hence the desiltation project will be appropriately planned so that it will not disrupt the normal water supply also the quality of the water that is pumped daily,” said Thilakan. He said that it will take two years to complete the project.
Aruvikkara dam cannot be blamed entirely for the flooding, says KWA official According to KWA authorities, even if the reservoir is desilted the shutters have to be raised.”The capacity of the reservoir can be increased through desilting, but in the event of continuous heavy rainfall, raising the dam shutters becomes imperative. Perhaps, after the completion of the desilting project, we may be able to delay the raising of shutters for one to one and a half hours at the most,” said an official source of KWA. The official said that silt filled reservoir is only one of many factors causing flooding.
“Rainwater harvesting is a solution that the authorities should consider seriously. Ground water recharging should happen and now the water is flowing on the surface as absorption is not happening. Such solutions will bring a positive impact,” the official added.