Check dams, weirs to help clean up Yamuna, says Satyendar Jain

The 57km-long Najafgarh drain crosses into Delhi from Haryana through the Dhansa border before entering the Yamuna river.

The Delhi government is constructing around two dozen temporary weirs and check dams along the two major drains--the Najafgarh drain and supplementary drain--that empty into the Yamuna river to keep a check on its suspended solid and ammonia levels, Satyendar Jain, the Capital’s water minister and chairperson of Delhi Jal Board, said on Sunday.

Delhi water minister Satyendar Jainsaid there are plans afoot to keep a check on the Yamuna river’s suspended solid and ammonia levels. (ANI Archive)

The 57km-long Najafgarh drain crosses into Delhi from Haryana through the Dhansa border before entering the Yamuna river. The second biggest drain in the city--the supplementary drain--originates from Kakrola regulator.

Jain said the irrigation and flood control department is executing plans to treat the largest pollution sources of the Yamuna river, as part of which the construction of 11 weirs has been completed on the supplementary drain while three weirs have been constructed on the Najafgarh drain. The work on 10 more weirs is currently underway.

A weir is a small barrier built across a stream which helps raise the water level slightly upstream.

“Weirs are erected to increase the retention of water. Currently, Delhi Jal Board treats wastewater from drains only by trapping it through its Interceptor Sewer Project, which is under the ambit of the Yamuna Cleaning Cell (YCC),” a Delhi Jal Board official said.

The YCC was constituted in November last year to ensure better coordination among agencies for cleaning the river. The cell is responsible for the execution of the Yamuna Cleaning Action Plan.

Jain said that some of the recently constructed weirs have already started to show positive results. “The irrigation and flood control department has submitted a test report about the impact of these initiatives. The test report of the drain water collected near Rithala STP, Rohini Sector 11 weir, Rohini Sector 16 weir, and Rohini Sector 15 weir shows that there is a reduction in total suspended solids (TSS) after the construction of the weirs. The TSS level went down from 166 mg/L in Rithala to 49 mg/L in Rohini Sector 15. Similarly, the ammonia level went down from 26 mg/L in Rithala and 18 mg/L in Rohini Sector 15 and the biochemical oxygen demand (BOD) level was reduced from 83 mg/L near Rithala STP to 27 mg/L at Rohini Sector 15,” the minister said.

BOD represents the contamination of organic material in water. A government official said that the I&FC department’s other measures include the installation of trash barriers and floating booms to trap floating solid materials, removal of hyacinth, raising boundary walls to prevent waste dumping in drain and erection of wire mesh grilles on bridges.

During the second phase, the government also plans to introduce floating rafters and aerators to improve the water quality levels, an official associated with the project said.

The Delhi government has announced its goal to clean the Yamuna river by 2025. The 22km stretch of Yamuna in Delhi, from Wazirabad barrage to Okhla barrage, is less than 2% of the Yamuna’s total length but accounts for nearly 76% of the total pollution in the river, the National Green Tribunal-appointed erstwhile Yamuna monitoring committee had noted.