The South Asia Network on Dams, Rivers and People (SANDRP) has said that water releases from the Ichari and Vyasi dams in Uttarakhand may have aggravated the flood situation in the Yamuna River during the 2025 southwest monsoon, when the river witnessed three flood spells in just two weeks between August 17 and September 1. The group’s analysis of official data shows that in several instances, the dam authorities released more water than was flowing into the reservoirs, thereby increasing the flood volume downstream.
According to SANDRP’s review, the Yamuna experienced a medium-scale flood on August 17, when discharges at the Hathnikund Barrage (HKB) in Yamuna Nagar, Haryana, crossed one lakh cusecs for 12 hours, peaking at 1,78,996 cusecs. A second, low-scale flood occurred on August 29, with discharges exceeding 50,000 cusecs for 21 hours and peaking at 83,774 cusecs. The most severe flood followed on September 1, when hourly water volumes stayed above one lakh cusecs for nearly 129 hours, with the peak discharge reaching 3,29,313 cusecs at HKB.
SANDRP said that two major dams—Ichari on the Tons River and Vyasi on the Yamuna—and three barrages—Dakpathar on the Yamuna, Asan on the Asan River, and Jateon on the Giri River—in the Himalayan segment of the Yamuna basin can significantly influence the river’s natural flooding pattern. However, with the discharge data of the three barrages unavailable in the public domain, their specific role in flood management could not be assessed.
The Ichari Dam, built in 1972 on the Tons River in Dehradun district, has a live storage capacity of 3.159 million cubic metres (MCM) and a gross storage capacity of 4.681 MCM. It diverts water to two hydroelectric projects—the 240 MW Chibro and the 120 MW Khodri. The maximum recorded flood peak at Ichari was 5,683 cumecs in August 2019.
During the August 17 flood, the dam released 1,145.51 cumecs (about 40,453 cusecs) more water than it received in inflows, lowering its reservoir level by over 10 metres within 10 hours. SANDRP said this indicated that the dam’s releases contributed to the first flood spell in the Yamuna. Before the second flood on August 29, the Uttarakhand Jal Vidyut Nigam Limited (UJVNL), which operates the dam, twice emptied the reservoir—on August 24 and 26—creating what the group called “artificial floods.” On August 31, a day before the third flood, the dam released 2,300.85 cumecs (81,254 cusecs) more water than inflows, again lowering the reservoir by over nine metres within three hours.
The Vyasi Dam, also operated by UJVNL and commissioned in May 2022, was found to have followed a similar pattern. Located near Juddo village in Dehradun district, the 86-metre-high dam diverts water for the 120 MW Vyasi Hydroelectric Project and has a gross storage capacity of 13.69 MCM. During the first flood spell on August 17, it released 2,145.37 cumecs (around 75,763 cusecs) more water than inflows, lowering the reservoir by nearly eight metres in 16 hours. SANDRP said this additional discharge “appears to have added to the flood volume.”
During the second, smaller flood at the end of August, Vyasi’s releases were below inflows, with water stored instead of released, which SANDRP said “compromised the river’s natural flooding pattern.” But during the high-scale flood on September 1–2, the dam released 2,153.13 cumecs (76,037 cusecs) and 482.05 cumecs (17,023 cusecs) more water than inflows, lowering the reservoir and adding to the river’s flood volume.
The Ichari and Vyasi dams are located roughly 75 to 80 kilometres upstream of the Hathnikund Barrage, with an estimated lag time of 10 to 15 hours for the released water to reach the barrage. Since discharges from both dams are regulated at Dakpathar Barrage, and the discharge data for Dakpathar, Asan, and Jateon barrages are not publicly accessible, SANDRP said it is difficult to assess the cumulative impact of these structures on the Yamuna’s flood behaviour.
The group emphasised that given the capacity of these dams and barrages to turn natural floods into disasters, their operational data and discharge records must be made public to ensure transparency and accountability during the monsoon season.
"The full hourly discharge data from Ichari and Vyasi dams which we were able to document can be seen here", SANDRP noted.
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