Sand mining in small, steep hill rivers remains poorly quantified despite rising global concern over aggregate-driven ecological degradation. This study develops an integrated, indicator-based framework to evaluate the environmental and socio-economic impacts of manual and mechanical sand mining along the Langkaih River, Mizoram, Northeast India—a transboundary hill river recently subjected to a ban on mechanized extraction. Water quality was assessed at upstream, active, and downstream sites using the Water Quality Index (WQI) and a novel Water Quality Impact Gradient (WQIG), combined with turbidity analysis and livelihood surveys. These datasets informed two composite indicators—the Sand Mining Vulnerability Index (SMVI) and an Integrated Sustainability Index (ISI)—linking environmental pressure, socio-economic dependence, and adaptive capacity. Results show that mechanical suction mining generated extreme turbidity plumes and WQI deterioration from “Poor” to “Unsuitable for drinking,” with a 470% WQIG increase and high vulnerability (SMVI ≈ 64). Manual extraction caused moderate, reversible impacts (WQIG = −29%), higher employment intensity, and greater overall sustainability (ISI = 0.91 vs. 0.27). The framework transparently differentiates mining methods by environmental and livelihood performance, supporting evidence-based regulation in data-limited hill systems. The findings provide a transferable model for sustainable sand governance to protect drinking-water security and riverine ecosystem health across Himalayan and tropical basins.
Zonunsanga et al. (Tue,) studied this question.