Study On Groundwater Pollution Early Warning In Shuhe Basin Of Juxian County

Groundwater is an important part of water resources.Compared with surface water,groundwater has the advantages of uniform spatial and temporal distribution,better water quality,relatively low treatment cost and easy exploitation.However,once groundwater is polluted,it will be difficult to recover and control.With the extensive and rapid development of social economy,a large number of industrial,agricultural and living pollutants enter into groundwater and cause groundwater pollution.More than 70% of the 640 cities in China have serious water pollution.Water shortage and water pollution have become an important problem restricting economic development and affecting human life and health.Therefore,the study of groundwater pollution early warning is of great significance to the protection of groundwater.Shuhe Basin in Juxian County is located in Juxian County,Rizhao City,southeastern Shandong Province.Groundwater is the main source of drinking water in the basin.With the development of economy and society,a large number of industrial pollutants are discharged and excessive use of chemical fertilizers and pesticides in agricultural production has caused groundwater pollution to varying degrees,which has threatened the safety of drinking water and restricted the development of local economy.In view of this situation,we take Shuhe Basin in Juxian County as the research area to carry out the early warning work of groundwater pollution in this area,in order to provide a reasonable basis for groundwater protection and rational development and utilization in this area.Based on the comprehensive analysis of the existing data and the actual field sampling survey,this paper carries out the early warning research on groundwater pollution in Shuhe Basin,Junxian County,and mainly carries out the following research work:(1)The groundwater quality was evaluated by Nemerow index method in high and low water periods.The groundwater quality was divided into five grades,and the groundwater quality zoning map was obtained.The results showed that the groundwater quality types in the study area were between good and bad,the area with the largest distribution area was the better water quality area,followed by the poorer water quality area,mainly distributed in the population.In the dense urban areas,the areas with good water quality are the smallest,with partial distribution and sporadic distribution in some areas as the main distribution.(2)The groundwater quality situation in the next three years is predicted by exponential smoothing method.On this basis,the groundwater quality change trend is analyzed by Spearman rank correlation coefficient method based on the long-range groundwater quality observation data.The groundwater quality change trend zoning map of the study area is obtained.The results show that the groundwater quality change trend is divided into three categories,which are: Water quality is getting better,water quality is stable and water quality is deteriorating.The largest area is water quality stabilization area,followed by water quality deterioration area and water quality improvement area.Water quality deterioration area is mainly located in densely populated urban areas,which is related to a large number of industrial enterprises and large amount of pollutant discharge.Water quality improvement area is only distributed in a small area in the northwest corner of the study area,while the remaining area is located in the remaining area.It is a stable area of water quality.(3)Using DRASTIC model,the groundwater anti-fouling performance is evaluated and evaluated individually.According to the comprehensive index of anti-fouling performance,the groundwater anti-fouling performance is divided into five grades,and the groundwater anti-fouling performance zoning map of the study area is obtained.Considering the point source and non-point source pollution in the study area,the pollution load risk assessment is carried out,and the pollution load risk zoning map of the study area is obtained.Considering the water-rich aquifer and the grade of water functional zone,the groundwater pollution hazard assessment was carried out,and the pollution hazard zoning map of the study area was obtained.Based on the raster superposition function of Arc GIS software,the groundwater pollution prevention performance evaluation,pollution load risk assessment and groundwater pollution hazard assessment results are combined to get the groundwater pollution risk comprehensive index value.According to the size of the comprehensive index,groundwater pollution risk is divided into three grades,namely low pollution risk,medium pollution risk and high pollution risk.The results show that the area of groundwater with low pollution risk is the largest in the study area,mainly distributed in the eastern and western regions of the study area,followed by medium-risk groundwater,mainly distributed in the central region of the study area.The area of highrisk groundwater is relatively small,mainly distributed along the banks of Shuhe River in strip shape,though.The distribution area is small,but it mainly distributes in the first-class protected areas of several important water sources.(4)According to the groundwater pollution early warning index system,the corresponding relationship between warning degree and warning line is delineated.The results of groundwater quality assessment,water quality change trend analysis and groundwater pollution risk assessment in the whole study area are superimposed according to the corresponding relationship between the delimited warning degree and warning line.The warning degree is divided into five categories: no warning,light warning,medium warning,heavy warning and giant warning.The results show that the giant and heavy police areas in the study area are mainly distributed in the densely populated urban areas on the West Bank of Shuhe River,which is related to the high inherent vulnerability of groundwater aquifer and the high risk of industrial point source pollution load,which makes the groundwater quality in this part of the area worse and deteriorating trend;the middle police area is mainly distributed in Shuhe River.The groundwater quality of the two sides of the river and its tributaries is relatively good,and the trend of water quality change tends to be stable.The pollution load is mainly agricultural pollution from non-point sources,and the pollution risk is medium.The other areas are light-warning and non-warning areas.The groundwater quality is good,the trend of water quality change is stable or better,the pollution load is low,and the risk of groundwater pollution is low.