Najafgarh drain
The Najafgarh drain or Najafgarh nalah, which also acts as Najafgarh drain bird sanctuary, is another name for the northernmost end of River Sahibi, which continues its flow through Delhi, where it is channelized, and then flows into the Yamuna. Within Delhi, due to its channelization for flood control purposes, it is now erroneously called "Najafgarh drain", and gets this name from the once famous and huge Najafgarh Jheel (lake) near the town of Najafgarh in southwest Delhi and within urbanized Delhi.
Background
Etymology
Within the National Capital Territory of Delhi, this channelized waterway misclassified and misnamed as the Najafgarh drain or nullah is the continuation of the Sahibi River and an elongation of the Najafgarh Lake.History
During the 1960s and before, the rain-fed Sahibi River, which originates in the Jaipur District of Rajasthan, passing through Alwar District in Rajasthan and Gurgaon District in Haryana, entered Delhi near Dhansa and spilled its overflow in the Najafgarh Lake basin. This overflow created a seasonal lake; an area of more than was submerged in some seasons. This water then continued to flow on the other side, forming a tributary of the River Yamuna. In the following decades, this Sahibi River flow reaching the Dhansa regulators was channelized by digging out a wide drain and connecting it directly to the River Yamuna. This channelization also drained off the seasonal Najafgarh Jheel that had formed there previously. The channelized drain from Dhansa regulators to Keshopur Bus Depot on Outer Ring Road is wide with thick and high embankments. A vast amount of water is retained in this widened drain by closing the Kakrola regulators under Najafgarh Road to recharge the local ground watertable; hence it acts like an elongated lake as well. The drain has been much widened over the years to drain all the water which in earlier decades used to collect in the Nagafgarh Jheel basin; this was supposedly done to remove the threat of flooding in Delhi. Before the draining of this lake in the 1960s by widening of the Najafgarh drain by the Flood control and irrigation department of Delhi the lake in many years filled up a depression more than in rural Delhi, It had an extremely rich wetland ecosystem forming a refuge for vast quantities of waterbirds and local wildlife. The lake was one of the last habitats of the famed and endangered Siberian Crane which has all but vanished from the Indian subcontinent now. Till before independence many British colonial Officers and dignitaries came in large parties for waterfowl hunting every season.Hydrology
Course
The 51 km-long Najafgarh drain starts at Dhansa and joins the Yamuna river near Wazirabad. Najafgarh Drain is canalized after Bharat Nagar up to confluence to River Yamuna at Downstream Wazirabad Barrage.Wetland bird sanctuary
The wide and deep drain acts as an elongated lake maintaining water-level even during the summer months, leading to recharging of ground water table, and the drain's elongated water body with trees planted on both its embankments acts as a wildlife and bird sanctuary which during the winter months attracts vast numbers of migratory birds and also supports local wildlife year-round.Infrastructure
Forested embankments
The Najafgarh drain has been much widened over the past decades and now has thick mud embankments on both its sides to channel the waters and protect Delhi from floods, these embankments have been planted with thick forest cover which serve as a much needed habitat for remnant local wildlife occurring in nearby and surrounding farmlands including common foxes, jackals, hares, wild cats, nilgai, porcupines and various reptiles and snakes including the dreaded cobras. Many local birds including waterbirds roost and nest in these trees.Sections of the forested embankments of Najafgarh drain are currently classified as and are featured in Protected Forests and Recorded Forests as "M. P. Green area Najafgarh Drain ", "Afforestation M.P.Green Area Najafgarh Drain " and "Chhawla or Najafgarh drain city forest ".