Impacts of urbanization on flooding in Jialu river basin

Abstract

Urbanization changes the hydrological process in urban areas by increasing impervious surface area. This study explored the impact of impervious surface change on the flooding process at the catchment above Zhongmu in the Jialu River basin. Three typical urbanization scenarios were set up, and two flood events were used to calibrate and validate the HEC-HMS model. The impervious rate of the Jalu River basin increased continuously from 1998 to 2018 (18.6%-47.0%) and increased even faster from 2008 to 2018 (26.2%-47.0%). Before 2008, the change in the flooding process was not obvious, and the increased amplitude of runoff depth, peak flow, and flood volume were less than 2%. After 2008, the three characteristic values increased significantly, with a growth rate between 7.3% and 11.5%. The change characteristics are accelerated with the increase in the impervious rate. Our findings are helpful in understanding the variation law of the flooding process in urbanization and provide science and technology support for urbanization construction.