Influence of Landscape Pattern Changes on Runoff and Sediment in the Dali River Watershed on the Loess Plateau of China

The large-scale Grain for Green project on the Loess Plateau of China significantly changes the regional landscape pattern, which has a profound impact on runoff and sediment process. The relationship between landscape pattern and runoff and sediment in the Dali River watershed is established. Cropland and grassland areas in the watershed show a downward trend, whereas the woodland and building land increases continuously. The Number of Patches (NP), Patch Density (PD) and Landscape Diversity (SHDI), Landscape Division Index (DIVISION) increase significantly. The Largest Patch Index (LPI) and Landscape Shape Index (LSI) show overall change in the rising and falling rule. The Contagion Index (CONTAG) and Cohesion Index (COHESION) first increase, then decrease. A decreasing trend is shown by runoff and sediment. The annual runoff in 2010 was 29.76% less than in 1960, and the annual sediment load was 84.87% less. NP, PD, COHESION, DIVISION and SHDI have a significant negative correlation with runoff and sediment, and CONTAG and runoff sediment are positively related. This study could provide theoretical support for guiding watershed land use and landscape planning to effectively reduce runoff and sediment transport.