Assessment of hydrological response to soil and water conservation measures in the Loess Plateau based on a novel modeling framework

Abstract

Soil and water conservation (SWC) measures play a critical role in controlling soil erosion and protecting water resources on the Loess Plateau (LP). However, their impacts on hydrological processes remain insufficiently understood. This study develops a novel hydrological modeling framework that integrates both infiltration-excess and shallow saturation-excess runoff mechanisms. We applied the model to two pilot areas on the LP and systematically evaluated the hydrological response under various SWC measures based on qualified simulated rainfall-runoff events. The results showed that the berm measure had a high Manning roughness coefficient of 0.12, the artificial grassland measure showed a high stable infiltration rate of 0.79 mm/min, and the terracing measure demonstrated the highest initial infiltration rate of 2.23 mm/min. Compared to other measures, the berm measure was most effective in reducing surface runoff, with its runoff component was mainly in the form of interflow, accounting for 94.2 %. Additionally, terracing and artificial grassland measures showed relatively small percentages of shallow saturation-excess runoff, accounting for 0.7 % and 0.4 %, respectively. This study highlights that, when balancing hydrological benefits with socio-economic feasibility, the berm measure on steep slopes has greater potential for reducing runoff, while terracing and artificial grassland measures on gentle slopes offer a more ecologically sustainable watershed management approach.