Impact of land use on frequency of floods in Yongding River Basin, China

Abstract

As the debates surrounding the negative influences of flood control using dams or reservoirs on the eco-environment become fierce, non-structural flood control measures like land use change gain more attention. This study researched the effect of integrated and single land use changes on three floods at small, medium and large scales, respectively, in Yongding River basin. A SWAT (Soil and Water Assessment Tool) model was used to simulate the effect of integrated and single land use changes on floods of different scales. The single land uses were set as S1, S2, S3 to represent the agricultural, grass and construction land changes. The results showed that: (1) the integrated land use changes reduced the small flood, the medium flood and the large flood by 14%, 13% and 5%; (2) the land use management functioned most effectively on medium-scale floods and least effectively on large-scale floods; (3) S1 decreased the medium floods optimally by 24% with a 7-day maximum runoff volume as the indicator and by 29% with a 1-day maximum flood discharge; (4) S2 reduced the medium floods optimally by 21% with runoff depth volume as the indicator; (5) S3 increased the medium floods optimally by 15% with a 1-day maximum flood discharge as the indicator.