Estimating Impacts of Dam Development and Landscape Changes on Suspended Sediment Concentrations in the Mekong River Basin’s 3S Tributaries

Abstract

The Mekong River Basin (MRB) is undergoing rapid dam development, which is altering the river suspended sediment concentration (SSC). In this study, we used satellite remote sensing records spanning 31 years to detect SSC changes (SSC prediction r2=0.78, RMSE=21.2 mg/L) due to dam development. We focused on the 3S basin of the MRB. We also used satellite data on nighttime lights, which reflect human settlement patterns, and land cover to explain SSC patterns. Our technique allowed for quantification of SSC changes due to dam construction (e.g., +120 mg/L near basin outlet), reservoir sediment trapping (e.g., −108 mg/L), deforestation, and human settlement (e.g., +117 mg/L near impacts). Our technique also demonstrated how the SSC of the 3S rivers compared to that of the Mekong mainstem over time (e.g., from ∼13% to 100% greater). Our comprehensive analyses of SSC records with dam development indicate that SSC changes will continue with ongoing dam and landscape development in the MRB. From a hydrologic perspective, SSC monitoring will be imperative for effective sediment and water management. Our satellite-based approach answers critical sediment needs of improved monitoring and adaptive management throughout the MRB and other global locations for practitioners who are engaged in real-world management of their river basins.