Applying Physiographic drainage inundation model to Risk Assessment of Water System-Donggangxi Watershed

Abstract

The assessment on damage of hydraulic engineering works is conducted for preventing hydraulic protection works destroyed by rainstorm event from causing disaster However since damage assessment area is very wide and can only be patrolled by human labor it is very difficult to prevent disaster by discovering not instantly visible structure damage like hollowing and subsidence Hence risk assessment of water system is used for investigating disaster cause and propose risk management strategy This research conducts risk assessment on Donggangxi Watershed and compares assessment results with historical flood area The Risk in watershed is evaluated by Hazard x Vulnerbility In hazard assessment flood frequency is usually analyzed with HEC-RAS model of 50 years recurrence period However there is some discrepancy between hazard factor evaluated by HEC-RAS and historical flood area Hence this research conducted simulation of Donggangxi water system with Physiographic Drainage Inundation Model (PHD) established by Tsai et al (1997) Yang et al (1998) Wong et al (2004) and Tsai et al (2007) Flood hazard is evaluated by “flood level and current riverwall height” of HEC-RAS and “flood level >0 5m” of PHD respectively The evaluation results are compared with historical area of rainstorm flood HEC-RAS which can only simulates flood overflow from riverwall is not capable of evaluate flood caused by long-time rainstorm whereas PHD is capable of evaluate flood area accurately Hence PHD is more accurate for evaluate flood hazard

Date of Award	2021
Original language	English
Supervisor	Jan-Mou Leu (Supervisor)