Presenter
Miss. Juan WU, Bureau of Hydrology Information Center of Taihu Basin Authority
Co-author(s)
Prof. Hejuan LIN, Bureau of Hydrology Information Center of Taihu Basin Authority
Sub-theme
3. Building Resilience for Disaster Prevention and Mitigation
Topic
3-5. Monitoring and early warning of water-related disasters
Body
Flood resilience management and decision-making are comprehensive strategies that integrate pre-disaster prevention, in-disaster scheduling and post-disaster reconstruction. High variation of land use and hydraulic engineering (including sluices and lowland polders) regulation have been widely recognized as the most important factors in flood control over the Taihu Basin. Under the background of frequent extreme rainstorm occurrence, the Highest Water Stage (HWS) of river networks often broke the historical records in recent years . Aimed at enhancing the capacity of flood control resilience and tackling high water stage problems of the Jiangnan Canal, including Changzhousan (CZ), Wuxida(WX) and Suzhoufengqiao(SZ), there is a clear and urgent need to acknowledge the spatial and temporal hydrological regime variation. In order to study the impacts of different hydraulic engineering floodwater drainage regulation schemes on flood characteristics of representative stage stations of the Jiangnan Canal, the intense rainstorm-induced flooding data during typhoon In-Fa of 2021 over the Taihu Basin was set as an example. The hydrologic and hydrodynamic model was applied to compare the Urban Optimization Scheme (UOS) and Regional Optimization Scheme (ROS). The results demonstrated that: (1) Compared with the flood characteristics before 2001, the highest water stage (HWS) of CZ, WX and SZ increased 0.45 m, 0.58 m, 0.34 m, respectively, the ratio of average precipitation and water stage increase (PZ) decreased 24%, 27%, 27%, respectively; while the flood rise rate (Zt) increased by 67%, 93%, 69%, respectively. (2) Compared with the water stage increase of the same 100.0 mm precipitation before 2001, the value was 0.15 m to 0.19 m higher after 2002 for the three stations. The results indicated that the flood peak water stage was higher, the peak time was advanced, while the flood hydrograph in short and fat shape has changed to sharp and thin shape, particularly significant in WX. (3) Compared with the UOS of hydraulic engineering floodwater drainage regulation, the HWS of CZ, WX and SZ for the ROS decreased 0.05 m, 0.07 m and 0.02 m, which indicated that the ROS had better effects on tackling high water stage problems of the Jiangnan Canal. Therefore, countermeasures and suggestions, such as strengthening the scientific dispatching of urban polders with basin and sub-region hydraulic engineering, expanding floodwater drainage project, and coping with risks through insurance sharing, are proposed to serve as references for future flood risk reduction and hazard mitigation over the Taihu basin.