Runoff quantity response of three urban mountain parks-hilltop subtype in humid subtropical climate based on SWMM

Abstract

With the development of sustainable stormwater management, urban parks have the advantages and necessities in constructing low impact development system to reduce and reuse stormwater. This study aims to understand the hydrological processes in small scale mountain watersheds based on three typical hilltop parks in Chongqing, China. Sub-catchment areas were divided into paved square type (PST), vegetation cover type (VCT) and mixed cover type (MCT). Native stromwater models by SWMM were created under 25 mm, 50 mm, 4 years and 20 years precipitation events to simulate the runoff quantity. The runoff quantity per unit area in different sub-catchments was provided as : PST > MCT >VCT. Runoff quantity affected by impervious surface percentage was the most significant compared to other parameters. Positive correlation between slop and runoff quantity was showed visibly when slop was above 42 degrees. Peak runoff could be affected by characteristic width of sub-catchment.