Author(s): Mukesh Kumar Yadav; Romeji Ngangbam; Victoria Ningthoujam
Linked Author(s): Ngangbam Romeji Singh
Keywords: Sand-Gravel mining Cross Section change River morphology
Abstract: Sand–gravel mining triggers change of the morphology of alluvial rivers as shifting of banks, flow depth, channel width, and more importantly disturbs the natural sediment transport regime. These changes are apparent due to the recent increase in unscientific sand–gravel mining. Thoubal River is one of the affected rivers in Manipur, India where sand–gravel mining has been rampantly practiced as compared to other rivers in the state. Unregulated sand–gravel mining has led to a deficient fluvial condition in the river system, where more sand–gravel has been extracted than the sediment capacity naturally available for removal, which has altered the river morphology and hydraulic regime. This study aims to undermine the impact of sand–gravel mining on the fluvial river system as change in the spatiotemporal cross profiles of river, short-term fluctuation of river bed morphology using HEC-RAS quasi unsteady sediment transport model supported by hydrographic surveys. The model results show the station which undergoes deposition/erosion within the simulated period of time. Geospatial analysis of river study area shows incoherent shifting of river banks within the period of 2010 to 2020. Further during field survey it was found that the sand and gravel mining has formed channel bars creating several channels and increasing braiding and dividing river flow, especially in the reach from Leirongthel to Changamdabi, where rampant sand–gravel mining has been observed.
Year: 2025