The National Green Tribunal (NGT) was informed by the Centre that congestion in the Yamuna River, particularly between the Wazirabad and Okhla barrages, impaired the accuracy of the 2023 flood forecasts issued by the Central Water Commission (CWC). The NGT had earlier taken suo motu cognizance following a newspaper report on the CWC’s failure to predict the severity of the floods experienced by Delhi last year.
According to the Ministry of Jal Shakti (MoJS) and the CWC, the 2023 floods in Delhi, which necessitated the evacuation of over 25,000 people from inundated areas, were exacerbated by unusually high discharges from the Hathnikund Barrage. The Ministry explained that the river’s flow at the Delhi Railway Bridge (DRB) site increased steadily, peaking at an unprecedented water level on July 13, which was significantly higher than previous records.
The MoJS’s detailed response highlighted that for a flood forecast to be accurate, the water channel needs to be in a free-flow state. However, this condition was not met due to several obstructions along the Yamuna’s course through Delhi. These included the partial opening of gates at the ITO Barrage, significant silt deposits forming islands, tree debris, and muck from ongoing bridge construction activities, all contributing to the river’s congestion.
The impact of these obstructions on the flow dynamics of the river was significant, with the MoJS stating, “If the free flow condition of the channel is compromised, then the forecast issued will not match with the actual forecast.” This mismatch was clearly demonstrated during the 2023 flooding events, where the actual water levels and the damage they caused were much greater than what had been anticipated.
