Lack of annual flushing results in severe pollution of Yamuna this year | Latest Delhi News

This year, the water level in the Yamuna did not exceed the emergency level of 204.5 meters at the Old Railway Bridge, the first time since 2014 and only one of six cases recorded since 1963. This means that the river has not experienced a single flood cycle. lack of annual flushing in the heavily polluted area between Wazirabad and Okhla and lack of recharge of the aquifer, experts say. High pollution loads, untreated industrial wastewater and domestic wastewater are now combined with meteorological factors in the form of iceberg-like foam blocks floating on the surface of the river.

For a river like the Yamuna, the four-month monsoon cycle, when minor floods occur, is crucial for annual cleansing when the river flows from mouth to tail in one stream. This helps maintain a continuous flow, improves aquatic life during this period, and also helps replenish underground aquifers in floodplains.

Of course, this flood does not stop the foam from forming, but it does provide improved river health.

Although Delhi has received an additional 63% rainfall this year, the Yamuna has not crossed the danger mark.

Experts said that besides rainfall, many factors influence the water level in the Yamuna. Key among them are reduction in rainfall in the upper catchment areas of the river and its tributaries, controlled release from the Hatnikund dam, as well as a number of precautionary measures such as opening of all barrages to prevent recurrence of floods, Senior Irrigation Director and Flood Control (I&FC) department official ) said.

“Apart from the river level at the Old Railway Bridge, a flood warning is also issued when more than 1 lakh (100,000) cusecs of water is released from the Hatnikund Dam. This year’s peak flow during the monsoon season reached only 87,071 cusecs, and that too once. In comparison, last year the discharge level crossed the 3.5 lakh (350,000) cusecs mark,” said the official, who did not wish to be identified.

A Haryana irrigation department official said, “Water in the Yamuna at Hatinikund Dam mainly comes from two tributaries in Himachal Pradesh and the Haryana catchment area. The Bata tributary joins the Yamuna near Bata Mandi; The Giri originates in the Kothai Hills, flows through the Sirmaur district of Himachal Pradesh and joins the Yamuna near the Uttarakhand border. This year, not much water has flowed into the Yamuna from these rivers.”

Rainfall data from the India Meteorological Department shows that of the 15 districts that cover the upper reaches of the river and its tributaries, 12, including Seemaur, Solan and Uttarkashi, received below normal rainfall.

According to the I&FC, since 1963 there have been only six occasions when lower maximum levels were observed – in 1984 (204.15m), 1987 (202.51m), 1991 (203.36m), 2004 (203.72m), 2006 ( 204.1m) ) and 2014 (204m).

Over the past 62 years, the warning level has been breached in 53 of them, making this a common annual occurrence.

Bhim Singh Rawat, a Yamuna activist and member of the South Asian Network on Dams, Rivers and People (SANDRP), said the shortage of fresh water being released into the river and high levels of pollution also highlight the river’s environmental flow problem, which is now being addressed. supported. “The river is dead because no water is being dumped into it. Low to moderate flood levels are an annual occurrence, and the river has rarely been this dry over the past decade. For a river like the Yamuna, the four-month monsoon cycle is crucial for annual cleanup, where the river flows from mouth to tail in one stream – as opposed to a fragmented, polluted river during the remaining eight months. It is also critical for replenishing floodplains and aquifers,” he said.

According to the Delhi Pollution Control Committee (DPCC), fecal coliform levels, an indicator of sewage entering the river, reached a record 4,900,000 MPN (most probable number)/100 ml in September. This was 1,959 times the standard of 2,500 MPN per 100 ml, indicating that annual flushing did not occur that year.

Rawat said the condition of the river is also drawing attention to the problem of electron flow.

“An environmental flow of 23 cusecs (1 cusec = 35 cusecs) has been recommended by the National Institute of Hydrology as well as the Parliamentary Standing Committee on Water Resources, but the river receives only less than 10 cusecs of water. Apart from less rainfall, less water is released from the Hatinikund dam. Release for 15 days before Chhath can also provide temporary relief from foam due to dilution,” he said.

Diwan Singh, an activist who stood up for the Yamuna in 2007, said: “The flooding is recharging the aquifers in the floodplains. The longer the flood cycle, the better the health of the river. Monsoon months are the only time when the river flows in its natural state. Otherwise, beyond Wazirabad the river is almost extinct.”