A 2-km stretch of the Najafgarh drain from Timarpur to Mall Road Bridge in north Delhi has been completely cleaned and the work upstream is fast progressing. According to sources, the annual silt deposit in the drain is over 3 to 4 lakh tonnes and around 85 lakh tonnes of solid waste is lying in the drain at present.
The silt, accumulated in the form of two solid mounds, is equal to the 85 lakh tonnes of waste at the Ghazipur landfill site. The 57-km-long channel, which flows into the Yamuna, has as many as 121 smaller drains that discharge sewage into it.
Sources at Irrigation & Flood Control Department (I&FC) said that drain has as many as 121 smaller drains discharging sewage into it. The annual silt or sewage deposit in the drain is to the tune of over 3 to 4 lakh MT and at present approximately 85 lakh MT of solid waste is lying deposited in the drain due to negect and apathy.
Comparing the silt if the drain to the landfill sites of the city, they said that the silt/garbage accumulated in the form of two solid mounds, is equal to the 85 lakh MT waste accumulated at the Ghazipur landfill site. “These under water mounds in the drain block the natural flow of water, especially during the rainy season resulting into overflowing of drains falling into it and cause flooding and water logging in the City,” they informed.
The two km stretch of the Najafgarh Drain from Timarpur to Mall Road Bridge has been completely cleaned by the concerned agencies, which is the main polluting source of the Yamuna River.
On the directions of the Lieutenant-Governor VK Saxena a de-silting monitoring centre has also been set up near Timarpur Bridge.
In the first phase to clean the 57-km long drain, the thick silt deposit, garbage and hyacinth have been completely removed from 2-km stretch of the 12-km stretch from Timarpur to Basai Darapur, said sources adding, “Starting October 15, nearly 17,000 MT of silt has been removed from this stretch in less than a month’s time.”
Informing about the methods used to clean the stretch, they said that it has been cleaned using the innovative concept of Partial Gravitational De-silting that uses the flowing water in the drain itself to take the silt away by loosening and churning of the silt.
“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.
This equipment is dragged into the drain by boats and they, in turn, churn and loosen the silt, which is thereafter carried out with flowing water in the drain,” they stated. Till now, the silt was being removed physically and being placed on the drain banks from where it would flow back into the drain during rains.