Evaluation Of Water Security In Datong Based On Improved Catastrophe Theory

Datong is located in the Beijing-Tianjin-Hebei water source protection area and the upstream water conservation area of Xiongan new area.It is an important energy and chemical base in China.With the economy development and ecological civilization construction,the urban water resources shortage,water environmental pollution,water ecological deterioration and other problems are becoming more and more prominent,thus water security has become the primary problem restricting the sustainable economic and social development of Datong.Therefore,the scientifically and reasonably evaluating the water safety status of Datong and the corresponding water safeguards are of great practical significance for the integrated and coordinated development of social economy,water ecology,water environment and water resources in DatongBased on previous studies,this paper improved the catastroph theory from three aspects: the Indian hut catastroph model was introduced into the evaluation system,and the control variables of the model were increased from 4 to 5.The entropy method is used to calculate the index weight,which reduces the subjectivity of index ranking.The transformation function of total catastroph series is constructed to avoid the interference to the evaluation result by the evaluation value approaching.Based on the systematic analysis of the concept and connotation of water security and the evaluation system of water security at home and abroad,according to the present situation of water security in Datong,the evaluation system of water security in Datong is constructed.The evaluation system is divided into three layers: target layer,criterion layer and index layer.The target layer is water security,the criterion layer includes five subsystems such as social economy,water ecology,water environment,water resources and water management,and the index layer includes 22 evaluation indexes such as groundwater exploitation coefficient,waste sewage discharge and total water resources.Taking 2017 as the current year and using county district as the evaluation unit,the improved mutation theory was used to evaluate the water security status of Datong.The evaluation results showed that the overall water security condition of Datong was poor in 2017.Among the 9 counties,only the urban area and Lingqiu county had a water security level of relatively safe,and the water security level is relatively unsafe for other counties including Xinrong district,Datong county,Yanggao county,Tianzhen county,Guangling county,Hunyuan county and Zuo yun county.According to the evaluation results of the water security subsystem,the main problems in the social-economic subsystem are the low economic development scale and high population growth rate;The main problems of the water ecological subsystem are over-extraction of groundwater,soil erosion and low proportion of ecological water;The main problems of water environment subsystem are large discharge of waste water,low sewage treatment rate and river pollution;The main problems of water resources subsystem are the relative scarcity and uneven distribution of total water resources;And the main problems of water management subsystem are the low water input,low efficiency of water using and leakage of pipe network.In view of the existing problems of water security in each county,the corresponding water security guarantee and improvement measures are proposed,which mainly include optimizing industrial structure and layout,controlling population growth,groundwater over-extraction area treatment,soil and water conservation and ecological restoration,river water environment treatment,and implementing the strictest water resources management system.This study can provide a reference for constructing water security system and planning water security strategy in Datong.