The Coupling Effect of Flood Discharge and Storm Surge on Extreme Flood Stages: A Case Study in the Pearl River Delta, South China

Abstract The low-lying Pearl River Delta in South China is subject to severe flood threats due watershed floods, sea level rise, and storm surges. It still unknown what extent how far inland surges rise impact the extreme stages. This study investigated coupling effect of discharge surge on stages by using site observations simulations generated Hydrologic Engineering Center-River Analysis System model. results show that discharges dominated middle upper Delta, while had maximum near river mouth. showed a significant increase after 2002 Hengmen waterway. design for post-2002 period were 0.23–0.89 m higher than pre-2002 ones at six return periods from 5 200 years examined this study. Their difference declined toward waterway reduced zero about 23 km away outlet. coincidence further escalates lower 30 estuarine waterways. Our quantify intensified are urban planning designing managing control facilities other coastal fluvial deltas.