IIT Roorkee finds severe silt accumulation in Satluj basin; NTPC proposes regulated mining solution

A comprehensive study by IIT Roorkee, commissioned by NTPC, has highlighted alarming levels of silt accumulation in the Satluj River basin, posing significant risks to bridges, roads, and townships in Himachal Pradesh. The findings, covering the period 2014–2024, indicate that while the riverbed remained largely stable until 2021, subsequent years witnessed drastic geomorphological changes due to recurring floods.

The study, which relied on remote sensing, GIS, multi-date and multi-sensor satellite data, divided the region into three zones: Tattapani, Sunni, and Chaba. Data shows that in 2022 and 2023, heavy floods triggered unprecedented sedimentation. In 2023 alone, the river recorded 2,861 million cubic meters of spillage—the highest since the commissioning of Kol Dam. Silt concentration peaked at 7,120 ppm, also marking a record.

Zone-wise analysis showed sharp increases in silt spread: in Tattapani from 7 hectares (2022) to 27 hectares (2023), in Sunni from 0.5 to 10 hectares, and in Chaba from 1.7 to 8 hectares during the same period. The massive sediment build-up forced NTPC to shut down Kol Dam operations for the first time on July 11, 2023.