Study And Application Of Safety Evaluation Method For Drinking Water Sources In Villages And Towns Based On Analytic Hierarchy Process

China’s village drinking water sources are characterised by a large number of points and a wide range of areas.In recent years,the state has carried out a census and protection management of water sources of 1,000,000 tons and 10,000 people,which has effectively ensured the safety of water sources in larger villages and towns.However,the number of village water sources below 1,000,000 tons and 10,000 people is huge,remote and with a small water supply,which makes it difficult to conduct census and survey,and the management department does not have enough information about them and manages them improperly,so safety accidents are frequent and the guarantee rate of safe water supply in villages and towns is low.There is an urgent need to establish an appropriate safety evaluation method for village water sources under1,000 tons and 10,000 people,to discover the weaknesses in protection and management through survey and evidence collection,mathematical model analysis and other means,and to accurately identify the safety status of water sources.In this paper,based on a nationwide study of 107 village and towns water sources of less than 1,000 tons and 10,000 people,a safety evaluation index system for village and town water sources was constructed based on the hierarchical analysis method,and107 cases were evaluated based on this system,and pollution prevention and control programs were proposed for typical cases based on the evaluation results.The main contents are as follows:(1)107 village and town water sources nationwide were investigated,basic information on the population served by the water sources,their types,water quantity,pollution status,engineering construction status,etc.was collected and water samples were tested.The results show that: the water quality of the water source is not up to standard and the water supply is not enough is its main problem,the pollution problems such as solid waste,traffic crossing,agricultural surface source and domestic surface source within the protection area of the water source is the direct influence factor of water quality safety,the engineering construction problems such as the lack of isolation protection and signage of the water source is the indirect influence factor of water quality safety.(2)The safety impact factors of village and town water sources are selected as evaluation indicators,and the safety evaluation index system of village and town drinking water sources is constructed according to the hierarchical analysis method and given weights,which contains the target layer,criterion layer and indicator layer,and the water quality comprehensive index method,single factor evaluation method and eutrophication scoring method are selected as evaluation models,and the affiliation degree is established by the fuzzy comprehensive evaluation method.(3)The construction method was applied to evaluate 107 village and town water source cases,and a schematic diagram of water source protection zones was drawn up based on Arc Map to analyse water quality,water quantity,pollution source prevention and control,engineering construction and water source safety conditions,and the evaluation results showed that a total of 51 water sources belonged to the safety condition,while the remaining 56 water sources belonged to the critical safety condition,and their protection and management efforts should be strengthened.(4)Among the 107 research cases,the fuzzy comprehensive evaluation index of the lake and reservoir type water source in East China(No.32)is the largest,and the overall is in the critical safety condition.Through further analysis,it is concluded that the water source mainly has problems such as traffic crossing,domestic surface source,agricultural surface source,ritual pollution,irregular water source isolation and protection facilities,and the type and quantity of signage does not meet the requirements,etc.This paper This paper proposes a pollution prevention and control program and estimates engineering investment at three levels,including pollution control from internal sources,pollution prevention and control from external sources and construction of water source protection and management projects.The proposal has been adopted by the water source management and included in the project implementation plan.