Identification of the inter-basin water diversion project-effected local flood risk factor by using the fishbone-diagram method

Abstract

When carrying out the inter-basin water diversion project, we must face problems such as the long river routing distance and complex hydro-meteorological conditions along the main channel. Under the condition of the unchangeable standard of the designed rainstorm, the changes of the underlying surface could inflect the designed flood. As a result, the drainage channel is not as consistent as the designed condition, therefore the flood discharge condition in the upper and lower sub-reaches changes, and the actual flow capacity of the hydraulic structure is reduced compared with the designed conditions. The above-mentioned situations could cause risk event of the rising of designed flood level in the left bank and will cause local flood risk, and also cause corresponding economic losses and social impacts. In this study, for the first time, the fishbone-diagram method is applied to identify the local flood risk factors of the inter-basin water diversion project. By using this method, the changes of characteristic values of watershed above cross section, villages, factories or other buildings at the outlet location of the drainage structures etc. are identified as the local flood risk factors, and there are mainly eight types of local flood risk factors which can be taken into consideration when selecting engineering and non-engineering measures to reduce or eliminate the risk factors. PACS: J0101