Ecological Risk Assessment Of Dam-Break Flood Based On Analysis Of Ecosystem Service Value

Ecological civilization and ecological security are closely related to human wellbeing,however,sudden extreme flood caused by dam-break will have an important impact on downstream ecological environment.Estimating flood ecological loss and carrying out flood ecological risk assessment have important reference value for determining ecological compensation,assessing risk level,conducting risk prevention zoning and risk management,and ensuring ecological safety.Therefore,under the funding of the General Project of the National Natural Science Foundation of China(51679222),this paper conducts assessment of the ecological risk of dam-break flood.The main work and results are as follows:(1)Numerical simulation of dam-break flood evolution.Starting from the hazard analysis of the risk source(dam-break flood),based on the MIKE 21 FM model,combined with specific engineering parameters and typical dam-break mode to carry out numerical simulation of dam-break flood of case reservoir project,basic water regime data were obtained,such as the maximum water depth,maximum flow velocity,and static water depth,which are used as the basis for establishing the flood hazardvalue loss rate correspondence relationship and flood hazard assessment.(2)Ecological loss assessment of dam-break flood.Based on the "value-loss rate"two-dimensional assessment model,the ecological value of various ecosystems in the study area is characterized by the ecosystem service value according to the ecosystem service value equivalent factor method combined with Xie Gaodi’s research results;The loss rate of various types of ecological value under different submerged water depths were determined according to principle of scientificity,reference,and operability,the total ecological loss is calculated and the spatial distribution of various ecological loss is calculated in the unit of township(block).(3)Ecological risk assessment of dam-break flood.Based on the "riskvulnerability-value" three-dimensional evaluation model,on the basis of the evaluation of dam-break flood hazard,ecosystem vulnerability and ecosystem service value of the flooded area,comprehensively evaluate the ecological risk level of dam-break flood.on this basis,risk prevention zoning and targeted regional ecological risk management was put forward.