Study On Investment Decision Of Urban Flood Control Strategies From The Perspective Of Climate Change

Global climate change has altered natural environmental systems in complex ways,leading to more frequent and severe damage to urban socio-economic systems by flood events.Therefore,from the perspective of long-term urban planning,it is an urgent problem for the government to formulate effective urban flood control strategies and mitigate flood risks.However,since flood risk is affected by environmental,economic and social factors,its occurrence frequency and disaster losses present significant uncertainty.Therefore,from the perspective of climate change,this paper focuses on the investment decision of urban flood control strategies.The main contents are as follows:(1)Aiming at the risk aversion of the insurance market to extreme flood events,an investment decision model for urban flood control strategy based on risk aversion is proposed.Firstly,the extended loss distribution approach(LDA)is used to estimate the expected economic losses of different levels of floods and Bayesian inference is used to estimate the parameters of the loss distribution;Secondly,the variance premium pricing principle is applied to convert the expected losses into premiums;Then the project value model is constructed using dynamic net present value(NPV)to determine the optimal investment time;Finally,the feasibility of the model is verified through a case and the impact of the main parameters in the model on the optimal flood control strategy is analyzed.(2)Aiming at investors’ mastery of extreme flood disaster information,an investment decision model for urban flood control strategy based on cognitive level is proposed.Firstly,the goal is to minimize discount unavoidable expected losses and investment costs;Secondly,with the introduction of uncertainty theory,extreme flood losses are treated as random variable and uncertainty variable respectively;Then,according to the variable categories,a dynamic mixed integer nonlinear optimization model is established respectively to determine the type and investment time of flood control measures;Finally,the feasibility of the model is verified through a case and the impact of the main parameters in the model on the optimal flood control strategy is analyzed.(3)Considering the multi-stage decision-making problem of flood control project investment,an investment decision model for urban flood control strategy based on Markov decision process(MDP)is proposed.Firstly,with the goal of minimizing investment costs and potential losses,the MDP method is applied to the problem of formulating urban flood control strategies;Secondly,consider that the transition probability is affected by both the system state and the action strategy;Then,two scenarios of finite stage and infinite stage are analyzed.Finally,the feasibility of the model is verified through case analysis and the impact of discount coefficient on the optimal strategy is discussed.