Signature Bridge construction debris choking Yamuna’s flow
Delhi’s iconic new structure, the Signature Bridge, has almost choked the city’s lifeline, the river Yamuna.
Five months after the bridge was inaugurated — on November 8, 2018 — the debris dumped into the river to carry out the construction of the bridge has not been removed.
Over time, this debris has combined with the soil and hardened, hampering the flow of water to such an extent that the entire aquatic ecosystem is now under threat, according to a spot check at the choke point by Hindustan Times, and multiple hydrogeology experts.
The experts said that the obstruction under the bridge was seriously affecting the river’s flow, and if it was not removed before the 2019 monsoon, it could even alter the river’s morphology by creating new islands that will affect its flow for good. The Yamuna gets more than 75% of its water during the monsoon months and only about 25% from melting glaciers.
“This [obstruction] would seriously affect the river’s longitudinal connectivity with time. The flow of biota [aquatic plants and animals] would be disrupted,” said Shashank Shekhar, an assistant professor of geology, with specialisation in hydrogeology, at Delhi University.
“As the river’s flow has been hampered, there would be less water downstream during the summer. The river would try to extract more water from the aquifers, which sustain it during the summer, to maintain the equilibrium. This would affect the water level of the aquifers.”
Explaining morphology, Shekhar said, the river brings loads of sediments during the monsoon. “If the flow is disrupted, the river slows down and starts dropping the sediments halfway. This can lead to formation of new islands, which are not natural riverine islands,” he said.
While the Signature Bridge was constructed by the Delhi Tourism and Transport Development Corporation (DTTDC), the project was being overseen by the state Public Works Department (PWD).
A DTTDC officer, who asked not to be named, admitted the debris had not been removed. “Work regarding [the] removal of the debris under the bridge has just been initiated. The work would be completed before the monsoon arrives. We are doing it on a priority basis,” he said.
“I will have to check how much debris is there. If there is any such debris blocking the river, it would be removed as soon as possible,” said Sanjeev Kherwar, Delhi’s PWD secretary.
The 675-metre Signature Bridge, built at a cost of ₹1,518.37 crore, is an eight-lane carriageway that was thrown open in November 2018 to connect north and northeast Delhi and reduce the traffic burden on the Old Wazirabad Bridge. It connects the Outer Ring Road on the western bank of the Yamuna river with Wazirabad Road on the eastern side.
AK Gosain, a professor of civil engineering at the Indian Institute of Technology-Delhi and a specialist in hydrological modelling, warned that the river cannot wash off the construction debris and demolition waste on its own. “If it was just the soil then the river could have washed it off naturally. But the construction and demolition waste have reduced the cross-section of the river,” he said. “This is a serious problem.”
In 2014, environment activist Vikrant Tongad moved the National Green Tribunal (NGT) urging that an environment clearance of the Signature Bridge project and its impacts on the river should be conducted. On the orders of the NGT, the assessment study was done by the State Environment Impact Assessment Authority (SEIAA) and clearance issued in 2017.
“This kind of debris is a violation of the environment clearance. The NGT’s landmark judgment of Maili se Nirmal Yamuna also prohibits dumping of any debris or solid waste in the river or its floodplains. Such activities would hamper the river’s ecological flow and disturb the aquatic life,” Tongad said.
Experts say that if the flow of a river is obstructed and its biotic life affected, it would take a toll on Yamuna’s health. “A healthy river is always better for the sustenance of a city through which it is flowing. It is always better to have a healthy river with life in it than a dead drain in which aquatic life has almost vanished,” said Shekhar.