3.3 Relative contributions of driving forces to urban flooding
The marginal effects of the six most important driving forces are shown in Fig. 5. With urban flooding density, the landscape shape index is complex, with a positive correlation ranging from 2.5 to 2.8 and a negative correlation ranging from 2.8 to 3.1. The slope shows a stepwise positive correlation with urban flooding density. As the green space ratio increased from 20% to 28%, the urban flooding density decreased from 0.010 to 0.005. The urban flooding density varies from 0 to 0.005 when the building congestion degree increases from 0.02 to 0.03. Building density experiences an initial increase and then stabilizes and finally drops.