Vulnerability Assessment And Protection Area Division Of Groundwater Source In Juxian County Of Shandong Province

Groundwater is an important natural resource for human beings and one of the main sources of daily water use.The groundwater is deeply buried,with good water quality,not easy to be polluted,and easy to be mined.But once the groundwater is polluted,it is very difficult to repair.At present,most cities and regions in our country have been polluted by groundwater in varying degrees.Groundwater protection is imminent,especially as a water source.Groundwater vulnerability assessment and protection area division are common effective methods to protect groundwater.Juxian groundwater source is located in Rizhao City,Shandong Province,which is mainly supplied by groundwater.Due to the lack of effective management and protection of water sources,the quality of groundwater is worrying.Therefore,this paper selects the groundwater source in Juxian County of Shandong Province as the research area to evaluate the vulnerability of the research area and divide the protection area,so as to provide a reasonable theoretical basis for the protection of groundwater in this area,which has practical significance for the protection of groundwater.Based on the project of investigation and evaluation of groundwater sources in Shandong Province,the following research is carried out on the basis of relevant data collection and field investigation:(1)This paper analyzes the characteristics and types of the study area,and summarizes the vulnerability assessment method drtic-iag based on the traditional DRASTIC model.Analyze and summarize the vulnerability evaluation parameters and the relatively important relationship between each parameter in the study area,determine the weight,do a good job in the parameter distribution and corresponding score of the whole area,and then stack them to get the vulnerability evaluation results.With the aid of ArcGIS software,the whole evaluation method makes use of the function of the software to map and calculate.(2)According to the analysis of basic hydrogeological conditions,hydrodynamic field and hydrochemical field in the study area,the conceptual model is determined.The MODFLOW module of GMS software is used to build the model.After the analysis and summary of the research area,the scope,boundary conditions,source and sink conditions,precipitation evaporation and the setting and adjustment of related hydrogeological parameters are determined to identify and verify the model.(3)Based on the flow model,the particle tracing model is established by modpath module in GMS,and the scope of groundwater protection area in the research area is determined based on Relevant specifications.The conclusions based on the research of the study area named Juxian are following:(1)The high vulnerability area is concentrated in the industrial area and the middle reaches of the Shuhe river.The industrial area is mainly affected by chemical plants.The middle reaches of the Shuhe River have large net supply,coarse medium particles in the seepage area and relatively large mining fraction,so the vulnerability is the highest.The high vulnerability area is concentrated in the river area except the middle reaches of the Shuhe River,mainly because of large net supply,coarse medium particles in the seepage area and medium vulnerability The area is concentrated around the study area,mainly because the medium particles in the seepage area are coarse and the groundwater is shallow;the lower vulnerability area and the lower vulnerability area are concentrated in the central plain area,with lower index scores and the strongest anti pollution performance of groundwater.(2)By comparing the results of the two methods,the results of the improved method are similar to those of the traditional method,which shows that the improved method is reasonable to some extent.Different places show that the factors of the improved method selection are more comprehensive and the evaluation results are more accurate.Therefore,the application of the improved drtic-iag method in the selected research area is reasonable and credible.(3)According to the hydrogeological conditions of the study area,determine the groundwater flow system and boundary conditions of the simulation area,determine the scope and boundary conditions of the model,model stratification,treatment of source and sink terms and relevant initial parameters of the model;identify the model according to the water level measured in 2016,and verify the water level measured in 2017.The results of recognition and verification show that the model fits well.(4)According to the groundwater flow model,the particle tracing model is established to determine the scope of the first level protection area,the second level protection area and the quasi protection area.On this basis,in order to monitor the situation of water source in real time,the monitoring area of water source is established.