Delhi Lieutenant Governor Vinai Kumar Saxena visited the Najafgarh Drain and inspected the ongoing works of de-silting of the drain using the scientific concept of “Partial Gravitational De-silting”. Najafgarh Drain is 57-km long with as many as 121 smaller drains discharging sewage into it. The annual silt deposit in the drain is to the tune of 2 to 2.5 lakh cubic meter and at present approximately 85 lakh cubic meter of silt is deposited in the drain.
The technique uses the flowing water in the drain to take the silt away by loosening and churning of the silt. As per the statement released by the Raj Niwas, conceptualized as a sustainable and cost effective cleaning measure, the exercise began recently. The concept ideated by Saxena from his experience of dredging in the ports of Gujarat, is a departure from the conventional method of de-silting that entails removing the silt through barges.
“Saxena entered the drain in a motor boat near Punjabi Bagh and spent over an hour inspecting the dredging work in about 1 km of area using the floating equipment and became the first LG ever to enter the Najafgarh Drain.
He has been, ever since taking over, consistently stressing and working towards cleaning the much maligned drain and converting it into an eco-tourism hub,” it read.“In conventional method of de-silting, the silt is removed from the drain and put on both banks of the drain, which incurs a major cost.
While some amount of silt is transported in trucks, a large quantity of silt flows back again into the drain with rainwater. Further, a part of the silt flowing back into the drain gets carried away with the water while most of the silk gets deposited at the bed which renders the entire de-silting process almost futile,” it said.
“However, the concept of Partial Gravitational De-silting uses the flowing water in the drain itself to take the silt away by loosening and churning of the silt instead of physically removing the silt, as is being done till now.
The churning of the thick silt deposit is being done with the help of non-conventional floating equipment and contraption modified with raker and spikes attached to the boats.
The modified equipment is dragged inside the drain by the boat and it in turn churns and loosens the silt. If the flow of water is fast enough, then the suspended silt can easily be taken along, thereby effecting natural de-silting,” the statement said.
The LG also directed officials to use this concept on a larger scale post trials and exploit technical parameters of the drain to the advantage.