Assessment of sediment retention benefits of check dams under changing environmental conditions in the Loess Hilly and Gully Region, China

The Loess Plateau region faces significant soil erosion challenges exacerbated by climate change and land use transformations. Check dams are critical soil and water conservation structures that reduce sediment transport, yet their long-term effectiveness under changing environmental conditions remains uncertain. This study evaluates the sediment retention benefits of check dams in the Yanhe River Basin, a highly erodible area in the Loess Plateau, under future climate and land use scenarios. We used the CMIP6 climate projections and the PLUS land use model to simulate future climate conditions and land use changes, integrated with the WaTEM/SEDEM model to predict soil erosion and sediment yield for the next 20 years under three scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). Results indicate that soil erosion and sediment yield will increase, particularly under high-emission scenarios (SSP5-8.5), where sediment yield may rise by 17.3% by 2040. However, check dams can effectively reduce sediment yield by 25.4%, mitigating the impact of future climatic and land use changes. These findings underscore the importance of maintaining and enhancing check dam networks for sustainable watershed management in erosion-prone regions. The study provides valuable insights for policymakers to implement long-term soil and water conservation strategies to mitigate the adverse effects of climate change on sediment dynamics.