Yuxi City Groundwater Environmental Quality Evaluation

With the rapid economic development,the sharp explosion of population,and the acceleration of urbanization process,groundwater pollution became serious day by day.It led to decrease for water resources,which can be used,intensify water resources crisis,and influence economic development,also bring up dangers for eco-environments and human health,These problems also existed in Yuxi,where human activities were frequent and environments were weak.The shortage of water resources and the groundwater pollution have become severe environmental problems.It is urgent to exploit rationally,manage and protect groundwater resources in Yuxi.Based on the groundwater's chemical analyses and dynamic monitoring data,and according to the groundwater quality standard and the drinking water quality standard of China,the groundwater quality was synthetically evaluated in this paper.The results showed that the groundwater quality was not in a good state and that groundwater was unfit for direct usage occurs at the center of the basin in this region.Groundwater contaminants,such as NH₄⁺,Mn²⁺,COD,nitrate,nitrite,mostly spread near the city and industrial enterprises.The midst is basic unqualified in the basin,only part of qualified area existence,the water resources function loses quickly, also depravation trend.The quality of crevice water and karst water is better,but the tendency is not optimistic.According to the DRASTIC index and the spatial superimposition function of MAPGIS,the essay analyses the groundwater antipollution capability,the result is: the area's groundwater antipollution capability is in the bad-medium scope,it is divided into three kinds of grade areas.Among them,the basin area's is basically in worse scope;the peripheral basin's is in medium scope.It reflects that mankind's activities pollute the basin groundwater easily.The groundwater antipollution capability,combining with groundwater's quality, recoverable resources,and the actual utilization comprehensive analysis,we have calculated the different water-rich block's potential for groundwater exploitation coefficient,and have evaluated utilization potentialitie and function.In overall,the west and northeast areas of the basin's karst water is good groundwater resource, which is suitable for a range of uses,there is some potentialities for the development and utilization,but at present it is primary for agricultural irrigation,did not give tap potentialities to the full.Then,on the base of evaluaion results of groundwater's quality,the antipollution capability and the groundwater's utilization potentiality,we have made the synthetical evaluaion by AHP to the Yuxi groundwater environment quality,the result is:The groundwater environment quality of good region mainly is the west and north of the basin;the medium region is the majority of areas;and the bad region is the middle of the basin nearby the Yuxi river.Finally,according to the Yuxi environment quality's characteristic,from the perspective of the emergency water supply security,the resources development and the environment coordination,we have proposed two emergency groundwater sources and certain groundwater resources's countermeasures of sustainable utilization,and according to the Yuxi city groundwater's main existence form,proposed the concrete groundwater's environmental protection measure.