Keeping drains clear of sediment, waste can prevent floods: Expert

GUWAHATI: Experts and conservationists say de-silting of drains by the Guwahati Municipal Corporation (GMC) alone cannot solve the worsening urban floods in the city until scientific measures such as placing debris-control screen and creating silting basin at the inlet point of the drains, are adopted by the government.
Sediment coming with the stormwater from hills as well as plains due to rapid deforestation and encroachment and the waste disposed in the drains and the river channels clog the drains and thereby cause floods in the city.
IIT Guwahati professor for water resources Arup Kumar Sarma said apart from adopting the ecological management practices like increasing grassland, tree cover and vegetation, steps to prevent waste and sediment going into the drains should also be equally taken up. “Flow of debris into the channel can be controlled by placing a suitable screen at the inlet of the channel. This will prevent the flow of debris and large-sized objects into the channel which may obstruct the channel and can promote deposition of silt. The screen should be cleaned at regular intervals of time to increase its efficiency,” he added.
He said creating silting basin at the confluence of the primary and secondary drains can also be an effective way to curb the sedimentation as such basin reduces the velocity of flow and deposition of silt occur at the basin and lesser amount of silt will enter the drains or channels.
Meanwhile, conservationist Hemen Lahkar said the authorities concerned must cover the drains with slabs to prevent people from throwing waste into the drains, which clogs the channels. “Bharalu, Mora Bharalu and Bahini rivers are examples of how garbage dumping has resulted into clogging of the channels,” he added.
Earlier this year, the GMC placed CCTV cameras at 10 locations of the Bahini rivulet to detect people throwing waste. Lahkar urged the civic body to step up monitoring by installing more CCTVs and also manually in order to save the drains and channels and thereby mitigating floods in the city.