Effect of land use/cover changes on runoff in the Min River watershed

Quantifying and interpreting the impacts that land use/cover change (LUCC) have on hydrology at basin scales are of great significance for the sustainable development of watershed ecosystems, water resources, and land management. The Soil and Water Assessment Tool was used to establish the regional model. The Min River watershed was divided into 236 sub-basins, and simulations showed the spatial distribution of runoff in each sub-basin with GIS-based image displays. We set five scenarios to investigate the negative hydrological effects characterized by reductions in the water yield. From 1995 to 2004, the effect of simulated mean annual runoff caused by LUCC was -12.61 m(3)/s and the climate variability caused -67.61 m(3)/s. From 2005 to 2014, the hydrological effect caused by LUCC was -2.38 m(3)/s and the climate variability caused -58.53 m(3)/s. The elevation, Shannon's diversity index, largest patch index, and interspersion and juxtaposition index were all characterized by strong relationships with the sub-basin outlet flows (adjusted R-2 = 0.572) using multivariate stepwise regression analysis. Redundancy analysis further proved that the reduction in grassland has led to a decrease in vegetation dominance while large increase in cultivated and residential lands has led to a higher degree of landscape richness and fragmentation, which has caused the reduced water yield. The restoration of grassland vegetation, as well as urban and agricultural water usage should be the primary focus of flow recovery.