Technical Studies

The purpose of this project is to evaluate the issues of adding “Specific Freeboard Areas” in the delimitation of the Two-Year Return Period Flood Zone from three different aspects: the technological analysis, the economical analysis and the legal analysis.

In the technological analysis, this project evaluates the uncertainty effects from the hydrological, hydraulic and geometrical factors for the delimitation of the Two-Year Return Period Flood Zone. Moreover, the reliability and feasibility of the added “Specific Freeboard Area” are also demonstrated. Our results show that the Two-Year Return Period Flood Zone underestimates the flooding risk due to the hydrological and hydraulic factors. Consequently, adding the “Specific Freeboard Area” is proved to effectively improve the reliability and feasibility for the delimitation of the Two-Year Return Period Flood Zone.

In the economic analysis, we further consider the impacts of human activities and try to establish the analytical framework for the delimitation of the Two-Year Return Period Flood Zone. Using theories from cost-benefit analysis, with results from technological analysis as inputs, we discuss and verify the economic rationale in adding the “Specific Freeboard Area” to the Two-Year Return Period Flood Zone. Other considerations in social and ecological factors are also included in our analysis.

In the legal analysis part, this study starts from checking the present laws and regulations about the delineation of 2-year Return Period Flood Zone under the requirements of Administrative Procedural Law and Process of Formal Rulemaking promulgated by Executive Yuan. This study then goes to the examination of authorities of the delineation of 2-year Return Period Flood Zone from the present Water Conservancy Law and related regulations. After the previous processes, this study reviews related laws and regulations, other than Water Conservancy Law, in order to find if there is any overlap or override by the above laws and regulations to the laws and regulations about 2-year Return Period Flood Zone. Based on the results from technological and economic analyses, it is established that the “Specific Freeboard Area” is definitely required in the delineation of 2-year Return Period Flood Zone and it can not be taken apart or ruled out. Consequently, this study combines all the results from legal, technological and economic analyses, and therefore employs methodology of juridical explanation to support the present legislation. This study also provides 3 suggestions of future modification in Water Conservancy Law and related regulations, in order to help water and legal professionals understand the rules of 2-year Return Period Flood Zone.