HYDROLOGICAL MODELLING OF YONGDING RIVER FOR FLOOD DRAINAGE BY DIGITAL TERRAIN MODEL

摘要

The Yongding River passes through the west side of the Beijing municipality which is of great importance to the city. It serves for irrigation, flood drainage, recreation and ecosystem maintenance. With the rapid urbanisation in recent years, the river faces increasing problems of water resources, especially severe flush floods in wet season. To support sustainable development of the area and secure human properties, the municipality sponsored the Digital Yongding River project where hydrological studies play a fundamental role. This paper presents modelling of the flows in the river for the rainfalls with different return periods. Digital elevation model (DEM) is used to delineate the catchments and set up the conceptual river model. After refinements of cross-sections, the Manning roughness and hydraulic structures are added in. Finally, simulations of water surface for three return periods (10 years, 20 years and 50 years) are carried out and are presented in inundated maps.