Planning response to flood disaster based on spatial and temporal simulation of rainfall and flood in county urban watershed

Abstract

In recent years, with the intensification of global climate change, the risk of urban waterlogging and regional floods in China has significantly increased. Shanghang County in Fujian Province is a typical small watershed city in the mountainous areas of western Fujian, with increasingly severe problems such as flood control and drainage, soil erosion prevention and control. This study is based on the needs of sponge city planning and development, selecting small watershed cities in typical mountainous areas of western Fujian as the research area. With the help of geographic information platform (GIS), a geographic database is established. SCS-CA hydrological model is used to quantitatively simulate the runoff generation and concentration process of watersheds around the city which would flow into the urban area under the scenario of extremely heavy rainstorm. The security pattern of flood disaster in the urban area was found out on the basis of comprehensive risk evaluation of flood disaster in Shanghang County. Furthermore, in the planning of sponge cities, the green and gray infrastructure in the urban area should be reasonably arranged, which can store and drain the simulated flood and rainfall amount, also Optimizing the urban landscape pattern and ensuring the ability of small watershed cities in mountainous areas to prevent and control flood disasters.