The civic authorities have come up with an offbeat solution to preclude overflow of city lakes during the present and future monsoons.
While nala widening works under the Strategic Nala Development Programme (SNDP) are still in various stages of progress at several locations across the city, the Lakes Wing of GHMC is busy deepening the surplus weirs of lakes, and fixing gates to them in order to take control of the outflows and thereby, prevent breaches to bunds.
Officials, on condition of anonymity, shared that orders for the same were issued by GHMC Commissioner D.S. Lokesh Kumar as a measure to prevent unforeseen emergencies.
Usually, weirs are constructed at the highest water level for every lake so that surplus water can exit without harming the bund. While gates are fixed for sluices to control the water flow for irrigation purposes, weirs do not have such controls as they are meant to drain all the excess water.
“However, the lakes in city have large amounts of silt that has reduced their holding capacity to a great extent. As a result, the danger of overflow or bund breach lurks even in the event of a moderate rain. The existing weirs are not sufficient to drain the water in a short notice,” explained an engineer.
Besides, sewage and flow of effluents described as ‘dry flows’ fill the lake to some extent even before monsoons, which reduces the capacity of the lake to take rainwater.
“Deepening of the weir along with fixing of gates will give us the option to drain the lake to some extent before monsoons in order to allow more rainwater. Once the water stabilises at optimum levels, we can close the gates,” the official says, and adds that this is better as precautionary measure than creating a breach when the lake starts overflowing.
As per the information shared by him, weirs are being deepened for close to 100 of the 185 lakes within the limits of GHMC, which have experienced crisis at some time or the other.
Weir deepened at Saroornagar tank
Already, the weir has been deepened and gates fixed for Saroornagar tank that has been receiving excessive inflows for the past two to three years due to storm water from Meerpet and Jillelaguda being diverted to the lake.
As the lake’s surplus channel has been inundating the surrounding colonies of Kodandram Nagar and Seesala Basti whenever there was heavy rain, officials have drained the lake to some extent before monsoons in order to avoid excessive outflows.
Gates for the surplus channel of Hussainsagar has been a long pending proposal, and if fixed, it could save the localities downstream which get water-logged every monsoon, say officials.
