The 22-km stretch of the Yamuna through Delhi continued to flow 19 cm above the danger mark on Saturday with incessant rains in the upper catchment areas of the river. The river maintained a constant level of 205.02 metres on Saturday. However, the forecast issued by the Central Water Commission says the river waters would start receding now to reach a level of 204.85 metres at the Old Railway Bridge by 6 pm on Sunday.

?The river is not affected so much by local rains. It floods when it rains in the upper catchment areas of the Yamuna in Uttarakhand. Drains in areas close to floodplains like Jahangirpuri, Burari, Garhi, Mandu and Batla House are being pumped regularly to prevent any back flow of water in the city,? said V P S Tomar, Engineer-in-Chief, Irrigation and Flood Control Department.

While the river never goes beyond the flood plains, the city gets flooded during rains due to the 18 major drains that experience reverse flow from the river while already under pressure from the city?s discharge.

People residing in the low-lying Yamuna catchment areas have been evacuated and Divisional Commissioner (East) is the nodal agency looking after the rehabilitation of residents.

The worst flood in Delhi?s history was recoded in 1978 when the Yamuna had breached the danger mark by 2.66 m on September 3, to record a level of 207.49 m. While the period between 2003 and 2007 was a relatively dry patch, the danger mark of the river was breached five times in the last decade ? 2000, 2001, 2002, 2008 and 2009.

Worst floods

1978: (September) Widespread breaches occurred in rural embankments of the Yamuna, submerging 43 sq km of agricultural land under 2 metres of water, destroying the kharif crop entirely. In addition, several colonies of North Delhi, namely Model Town, Mukherjee Nagar, Nirankari Colony suffered heavy inundation, causing extensive damage to property. The total damage was estimated at Rs 176.1 million.

1988: (September) The river experienced floods of very high magnitude. Approximately 8,000 families in Mukherjee Nagar, Geeta Colony, Shastri Park, Yamuna Bazaar and Red Fort areas were affected.

1995: (September) The situation worsened due to lack of coordination between various state agencies, leading to slow release of water from the Okhla barrage. The villages situated along the riverbed were flooded, rendering approximately 15,000 families homeless .

flood figures

202.00 m: The average water level of the Yamuna river at Old Railway Bridge during the summer months

204.22 m: The flood warning level

205.44 m: Level at which a high flood is declared

low-intensity flood: Declared when the water is above the normal level, but below the danger level. At this stage, there is no danger to life and property but official departments have to keep a watch on the future discharge, with the Tajewala head works in Haryana being the controlling point upstream

Medium flood: Floods in which water-levels are above 204.22 m and below 205.44 m.