Evaluation of Flooding Comprehensive Water Control Scheme－A Case Study of Ehuxi Urban Drainage Tainan City

Abstract

Currently under extreme climate condition short-time rainfall often exceeds 100mm which is much more than 65 8mm the capacity of drainage system of Zhuxi area or 78mm the capacity of drainage system of Taipei city Hence rainfall over 100mm will inundate most area in Taiwan Since flood can not be eliminated it is better to control flood hazard with“Not afraid of flooding”water drainage system At present water overflowing river dikes is hazardous because the environment has no flood tolerance Hence development of flood tolerant environment is the basis of building“Not afraid of flooding”urban drainage system Alternative engineering method make“Not afraid of flooding”water drainage system be tolerant to flood and fast recovery from flood For example erosion resistant and porous concrete material is adopted and the area of flood detention pond and green space is increased As a result capacity of environmental flood control is improved and environmental recovery speed after flood recession is also increased Building a “Not afraid of flooding”city water drainage system means rebuilding urban drainage system like sponges which absorb and release water quickly This research proves that after the first term remediation plan was finished Zhuxi is now equipped with “Not afraid of flooding”water drainage system which can handle excessive rainfall Quick water recession after 0823 heavy rain event which happens during construction also proved that making river bank revetment with flood toleranance and recovery ablity is more efficient than keep heightening flood protection works If the second term remediation plan is implemented it will add another 7 000m3 of flood detention area lower Q25 water level on upstream and midstream by 20cm and lower Q10 water level on upstream and midstream by 10cm The flood area will be reduced by 2 7 ha and about 1 100 people will be protected

Date of Award	2020
Original language	English
Supervisor	Jan-Mou Leu (Supervisor)