Landscape patterns and quantified attribution to runoff changes based on the Budyko framework in Nanning, China

The urban stormwater flood and its ecological effects are becoming increasingly prominent underlying the rapid urbanization of China. Nanning is a typical southern city with frequent flood disasters and an urgent need to conduct quantitative research and explore effective countermeasures. Therefore, the quantitative contributions of rainfall, evapotranspiration (ET), and landscape patterns to urban stormwater runoff are analysed using the Budyko framework in this paper. The results show that the rainfall, landscape pattern, evapotranspiration and runoff in Nanning have significant synergistic interaction. The change of rainfall has a positive effect on runoff increment, accounting for 5.9 similar to 12.3% of the annual rainfall. The change of the underlying surface parameter (n) has a negative effect on runoff decrement, accounting for -14.8%. Evidently, the blue (water space), green and grey infrastructure of the underlying surface and its spatial pattern largely determine the quantity and spatial distribution of storm runoff in Nanning City.