CHENNAI: After six decades of siltation, the state government will increase the capacity of Madurantakam tank in Chengalpet -- the second largest tank in the state -- by deepening it, strengthening the bund and remodelling the spillways at Rs 120.23 crore in anticipation of Nabard assistance. The rejuvenated tank may also augment the drinking water supply to Chennai.
After a detailed study, the PWD revised the parameters of existing storage level to 791mcft (million cubic feet) from 530mcft and full tank level to 32.15m from the existing 31.65m.
“The proposal has been forwarded to Nabard for loan assistance of Rs 120.23 crore. The state government has sanctioned Rs 1 crore for the current fiscal and the balance during the next financial year based on need,” said an official.
Located along the Chennai-Trichy national highway, the main source of supply to the tank is the Kiliyar river from Vandavasi and Nelvoymaduvu from Uthiramerur taluk.
Officials say the strengthening is required since heavy rain in 2015 filled all the tanks in the district and their bunds were breached causing flood. One of the primary reasons for floods is loss of storage capacity of the system and non-system tanks due to sedimentation. Madurantakam’s tank capacity fell by 24% as per a bathymetric survey. “The plan is to deepen the tank and use the earth for reclamation of foreshore land. We are converting the tank to balancing reservoir with regulated shutters,” the official said.
There had been periodic breaches of the tank’s bund until the MGR regime increased its capacity to 694mcft by providing 2ft high falling shutters in the weirs in 1985-86.