Zero precipitation in the upper catchment and substantially reduced dam discharges by 1 lakh cusecs, loss of storage capacity of Durgapur Barrage due to siltation has led the Damodar to cause extensive devastation in the lower valley.
Uncountable localities in East Burdwan’s Galsi, Raina, Jamalpur and Hooghly’s Arambagh, Goghat, besides Udaynarayanpur, Amta in Howrah have been receiving water by the Damodar flood waters since yesterday, especially after the Barrage mounted discharge to 2.79 lakh cusecs against its designed bearing capacity of 1.5 lakh cusecs, claimed Shashi Rakesh, member secretary, Damodar Valley River Regulation Committee.
At 5 pm today, the barrage maintained discharge rate at 2.39 lakh cusecs. The combined discharge by the Maithon and Panchet upper dams was reduced to 1.30 lakh cusecs from yesterday’s 2.5 lakh cusecs. Sanjoy Majumdar, executive engineer, Damodar Headworks of state irrigation department said, “Their discharge takes almost 10 hours to hit our lock gates and so, once they have stepped down discharge, we’d get the reduced water in the small hours tomorrow.” Up to then, barrage would have to choose for a very little slowdown, he claimed.
The unrelenting deluge by the Durgapur Barrage meanwhile has badly affected 212 villages in East Burdwan where 12,908 persons suffered the disastrous situation. In the district, 237 houses fully and 428 houses were partly destroyed. In Bankura, 620 houses were fully and 2402 houses were fully destroyed, the Disaster Management cells of the districts informed today.
On why the barrage can’t hold excessive discharge by the upper dams, Mr Majumdar said, “We’ve already suffered storage capacity loss due to continued siltation over the decades.” The barrage’s installed water bearing capacity was 10.273 million cubic metres. But since its inception in 1956, the barrage’s pond area has lost 52 per cent of its initial storage and siltation alone has reduced this by 37 per cent, the morphodynamic measurement of the alluvial Damodar by the Central Water Commission experts revealed. The study by hydrology expert, Prof S Nandy had claimed: “About 6 million cubic metre sedimentation was transported to the riverbed from the upper catchment through dam-discharge over the years.” The volume of sediment discharges ranged between 70 to 1308 MT per day, the research unearthed.