IIT Roorkee finds severe silt accumulation in Satluj basin; NTPC proposes regulated mining solution
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Shimla, Oct 3,
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.
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The siltation has already inflicted recurrent damage to key infrastructure such as the Thali suspension bridge, Shimla-Mandi road, and bridges at Tattapani and Sunni. The Public Works Department has estimated over ₹29 crore for road repairs and ₹8 crore for the Thali bridge restoration.
Interestingly, IIT Roorkee’s report notes that the silt deposits around Sunni are particularly suitable for use in construction material. NTPC has suggested regulated mining of the deposits, which could reduce water levels while generating economic value. The company has expressed readiness to issue an NOC to the state government for mining activities.
The findings signal both a serious environmental concern and a potential opportunity for sustainable utilization of natural deposits in the Satluj basin.
About the Author
The HimachalScape Bureau comprises seasoned journalists from Himachal Pradesh with over 25 years of experience in leading media conglomerates such as The Times of India and United News of India. Known for their in-depth regional insights, the team brings credible, research-driven, and balanced reportage on Himachal’s socio-political and developmental landscape.
