Risk Assessment And Dynamic Decision Of Urban Emergency Water Supply Under Emergency

Water is the extremely important resource for daily life of human beings and development of both industry and agriculture.And urban water supply system is the key way to ensure the water demand of these users which is known as one of the urban lifeline engineering.In real life,however,water supply system operates abnormally in emergent situation(such as earthquake,rainstorm and so on),which will affect urban development and usually bring immeasurable loss.So it is essential to conduct the risk assessment for urban water supply system and make countermeasures of emergency water supply.Based on the uncertainty theory,in emergency situation,this dissertation evaluates the risk of urban water supply system by using uncertain risk analysis and uncertain reliability analysis.Then a dependent-chance goal programming model is formulated to maximum the possibility that an event will occur.The developed models contribute to risk assessment and desired schemes under emergency for decision makers.The main contents are as follows.Firstly,uncertain measure is introduced to measure the possibility which an emergency occurs.Due to the uncertain water supply in emergent situation,it is assumed as uncertain variable.Then the function of water shortage is formulated under uncertain environment.Moreover,system vulnerability is calculated with the Markov latent effects model and uncertain reliability analysis.On the basis of these analyses,the loss function of water supply system is defined.Then the risk assessment model in which water supply is assumed as uncertain variable is established for urban water supply system.Besides,when an emergency situation occurs,water supply system operates abnormally which results in uncertain water demand and water supply.So water demand and water supply are expressed as uncertain variables.Then the function of water shortage considering multiple factors is developed under uncertain environment.On the basis of defined function of water shortage,the risk assessment model in which water supply and water demand are both assumed as uncertain variable is established for urban water supply system.Secondly,due to the insufficient water supply under emergency,the water demands of multiple users are not achievable at the same time.Under such circumstance,it is apreferred solution to create a priority structure.Then a dependent-chance goal programming is developed to maximum the possibilities of satisfying the water demands of users.Finally a hybrid intelligent algorithm is designed for solving the model.Thirdly,the risk assessment model is used to assess the risk of urban water supply system in Handan City.Beyond that,dependent-chance goal programming model is applied into emergency water supply in Handan City.Thus the desired water-allocation scheme is obtained.The research will enrich the risk analysis methodology and broaden the application of uncertain risk analysis and uncertain programming.The results will be conducive to risk assessment of urban water supply system and emergency water supply.