The Research On Comprehensive Evaluation Of Water Environment Safety Of Drinking Water Sources In Lanzhou

In order to provide scientific basis and practical guidance for the management and protection of water environment in Lanzhou Drinking Water source area,this paper provides a comprehensive evaluation on the safety of drinking water source in Lanzhou.Investigating the water environment problems in the source area,the ways of water pollution risk were studied.According to the research results,targeted measures were put forward to protect the water source area for improving improve the water environment safety and ensuring the drinking water quality safety.The main conclusions are as follows:(1)Based on the scope of water source area protected and influenced in Lanzhou,the administrative territorial entity of Xigu district,the regional DEM data and the watershed boundary,the small watershed system was divided by Arc GIS software.It is determined that the study area is composed of 23 natural subbases with different areas,with a total area of 442.28 km~2.(2)From 2010 to 2019,the water quality of drinking water sources in Lanzhou city is in good condition,with the water quality category of I~III.The over standard factors are TN and fecal coliform.It can be seen from the analysis of pollution factors that the poor quality of upstream water,the pollution risk of regional pollutant discharge and the high content of sediment are the important factors affecting quality of water.(3)During wet season and dry season,three accident scenarios were set up,including hazardous chemicals leakage,Xixin sewage main pipe leakage and debris flow emergency.They are used to forecast the water pollution incident.For example,the turbidity of water body rises to 200000 NTU after debris flow,which will reduce the water intake of water plant by half and affect 50%of urban domestic and industrial water.(4)The result of comprehensive evaluation shows that there is potential pollution risk of water quality in drinking water source area in Lanzhou City,and the safety of water environment is low.According to the potential environmental risks,the research puts forward the targeted measures for water source protection.