福州市主城区水系洪涝灾害成因及整治对策研究-水利工程专业论文.docxVIP

ABSTRACT Along with the explosive expansion of urban area and the increasing frequency of extreme weather events, the urban flood disaster is increasingly frequent, especially in the city located along tidal estuary. In this dissertation, according to the runoff processes from diverse sub-basins in northern mountain area and the flood water discharge processes out each urban drainage pipeline in term of four design rainstorm criterions, a numerical simulation model of flood control and drainage of it is established in allusion to the city at tidal estuary, by which the capacity of flood discharge and waterlogging drainage of the status quo is evaluated and the causes of flood disaster is revealed by the annlysis of the hydrodynamic characteristics of the river network within the main city. On this basis, flood control strategies are proposed matched with different design rainstorm conditions. In addition, the encounter risks of rainstorm and tidal level which are the most main factors resulting in the disaster are analyzed with copula fuction, and the risk of this disaster is calculated. This research mainly includes the following aspects: According to the water system information, a numerical simulation model of flood control and drainage is established with HEC-RAS software, and then the model is verified with the rainstorm data, flood control operation data and the flooding area during Typhoon “Longwang”. The capacity of flood discharge and waterlogging drainage of the status quo is evaluated by simulation flooding routing on four design rainstorm conditions. Results show that the discharge capacity of water system in Fuzhou city is unable to reach once in 5-year design rainstorm criterion. The hydrodynamic characteristics of the water system within the main urban area of the city are analyzed by the simulation of flood processing on the rainstorm with 5-year return period, in which the main causations of the disaster are respectively revealed from four factors—i