New Delhi: Has the ability of the Yamuna to carry excess water been impaired? Delhi govt’s Flood Control Report 2025 broaches this troubling issue. Data on the water flow seems to indicate that even smaller volumes are now pushing the river level to dangerous highs, suggesting that the Yamuna’s flood-carrying capacity within the capital has shrunk significantly.The water level in the Yamuna has crossed the 207-metre mark only five times since 1963. In 1978, 2010 and 2013, the river rose above this point only when the Hathnikund barrage in Haryana released 7–8 lakh cusecs of additional water. But in July 2023, when the city suffered its worst flood in decades with the level rising to 208.66m, the discharge at Hathnikund was a lot lower at 3.5 lakh cusecs. Worse, the Yamuna touched 207.48m this week when the released volume was only 3.2 lakh cusecs. Clearly, even smaller volumes at Hathnikund are proving threats in Delhi.
Experts point to rampant encroachment, concretisation and construction on the floodplain in Delhi, and the numbers are a clear warning that the city might not withstand a discharge of 7-8 cusecs from Hathnikund any longer.Professor CR Babu, who heads the Centre for Environmental Management of Degraded Ecosystems, didn’t have any doubts. “The width of the floodplain has drastically reduced,” he declared. “Due to this, even a small release from Hathnikund spikes the river level in Delhi and floods the low-lying areas. Also, see the Delhi Metro, road and railway bridges that have been constructed. Each new bridge resists the movement of the floodwater. The floodplain has also shrunk due to too much construction.”He added that silt and sediment deposited due to untreated sewage being dumped in the river couldn’t be washed away entirely by the seasonal floods.According to professor AK Gosain, professor emeritus, IIT-Delhi, while floodplain encroachment was certainly a factor, the Central Water Commission needed to recalibrate its rating curve, meaning the manner in which discharge and water level are measured. “If the riverbed level changes, it would impact the gauge discharge curve, which is formulated based on actual flow and discharge,” Gosain explained. “I doubt if the curve being used has been updated. Maybe that is why lower discharge still results in higher water levels.”He agreed that encroachment of the floodplain deprived the river of space to accommodate additional discharge. If that was the issue, the current flood is “of our own making”, he said.An irrigation and flood control department official pointed out that silting the entire river was a difficult task. All that can be done is to clear some silt from the river’s course. “There are several concretised ghats, which don’t absorb the floodwater,” he added.Bhim Singh Rawat of the South Asia Network on Dams, Rivers and People also said that the fact of “three barrages along just a 22km stretch of the river” affected water dynamics. Quoting a jal shakti ministry report that the closure of the barrage gate at ITO resulted in half a metre of flow in upstream areas, Rawat said the report revealed that water discharge calculation formulae of these barrages, including Hathnikund, were “inaccurate”.Cautioning that a disastrous flood was round the corner, Rawat said, “These floods have again underlined the undisputed fact that the Yamuna floodplain in Delhi has greatly lost its flood-carrying capacity. The large-scale infrastructural projects along, across and on the floodplain over the past decade and a half have fragmented and permanently damaged a huge chunk of the floodplain. These structures have also greatly compromised the flooding pattern of the river.”
