[Influence of Pervious/Impervious Pattern on Runoff and Pollution in Parcel-based Catchment].

Determining the influence of pervious/impervious underlying surface pattern (composition, position, proportion, etc.) on the generation capacity of surface runoff and pollution in the urban parcel-based catchment could aid in alleviating the urban waterlogging and control non-point source pollution significantly. Landscape metrics were used to analyze the relationship between the characteristics of pervious/impervious underlying surface pattern and total runoff () and the cumulative load of dissolved pollutants () and particulate pollutants (). The results showed that: ① For the metrics of fragmentation, the patch density (PD) was positively correlated with and . and largest patch index (LPI) was negatively correlated with them. Especially, the PD exhibited a significantly positive correlation with (=0.59, <0.05, calculated in COD). However, the LPI exhibited a significantly negative correlation with (=-0.60, <0.05, calculated in COD). ② For the metrics of complexity, landscape shape index (LSI) was positively correlated with and , and mean shape index (MSI) was negatively correlated with them. Especially, the LSI exhibited a significantly positive correlation with (=0.61, <0.05, calculated in TP) significantly. However, the MSI exhibited a significantly negative correlation with (=-0.62, <0.01, calculated in TP) significantly. ③ For the metrics of vergence, the split index (SPLIT) was positively correlated with and , and the cohesion index (COHESION) was negatively correlated with them. The COHESION exhibited a significantly negative correlation with (=-0.59, <0.05, calculated in COD), whereas the SPLIT exhibited a significantly positive correlation with (=0.6, <0.05, calculated in COD). ④ In the planning on the distribution and pattern of pervious surface under small-scale catchment, it is suggested that the scattered small-regular patches should be transformed to large-irregular patches or patch group. The relationship of the fragmentation, complexity, and vergence of pervious/impervious surface, with the runoff generation, and pollution output in parcel-based catchment was analyzed, which provided a new method for rainfall runoff and pollution control by considering rational allocation of LID facilities in terms of its pattern characteristics (area, distance, shape, etc.).