Assessing the impact of sand mining on channel morphology: a case study of the Raidak-II river in the Himalayan foreland

Abstract Sand mining plays an important role in changing the morphological features of any river. The present study aims to investigate the long-term geomorphic consequences of instream sand mining on the Raidak-II River in the Himalayan foreland basin over 24-year timescales (2000–2024), presenting a more comprehensive assessment of channel morphological dynamics. Multi-temporal satellite datasets (Landsat and Google Earth images) and various geospatial techniques have been used using ArcGIS 10.4.1 to quantify key morphological parameters, including Channel Index (CI), Valley Index (VI), Sinuosity Index (SI), Braiding Index (BI), Total Braiding Index (TBI), Bar Mode (mbr), and bar-to-channel area ratio (BA/CA) across three river segments (A–C). Transect analysis and detailed mapping of sandbars were used to trace how the river’s width and bar areas changed over time across different segments. The results show that significant mining-induced modifications occurred: Segment-B and Segment-C widened, while Segment-A narrowed; CI, VI, and SI decreased, demonstrating channel simplification and straightening. Braiding indices fluctuated, with bar mode variability, reflecting bar fragmentation and pit formation. BA/CA ratios decreased across segments, showing significant channel deterioration. The spatio-temporal changes of mining bar areas indicate channel bar instability. These findings reveal how long-term sand mining profoundly alters river channel morphology in the Himalayan foreland basin. Using GIS and remote sensing approaches, it provides evidence to guide sustainable sand-mining policies and river management. The findings emphasize the need for careful planning, monitoring, and regulations to protect river health, offering a framework for responsible resource use and policy development in similar Himalayan River systems.