Proposed APLIE method for groundwater vulnerability assessment in karst-phreatic aquifer, Shandong Province, China: a case study

Groundwater vulnerability assessment has become a useful tool to delineate areas for the prevention and control of groundwater pollution. The paper proposed the APLIE method by combining the DRASTIC, PI, COP, European approach with the characteristics of karstphreatic aquifer in North China in the help of ARCGIS (R), which was used to assess the groundwater vulnerability of Dawu water source, Shandong Province, China. Water abundance (A), protective cover (P), types of land use (L), infiltration amount of precipitation (I) and groundwater exploitation (E) were picked up to compose the index system for characterizing the hydrogeology and environmental geology setting and evaluating the aquifer vulnerability. Weights of new index system were reassigned using the analytic hierarchy process method based on the relative importance of indexes. The assessment results indicated that groundwater vulnerability mapping with APLIE method is in better agreement with the current hydrogeological and environment geological understanding of Dawu water source area compared with the results obtained from PI and COP methods. And the exceeding standard subareas of ammonia nitrogen (NH4-N) and electric conductivity in the study area proved the reliability of groundwater vulnerability results. Subareas of vulnerability were portioned by natural breaks based on the spatial platform of ARCGIS (R). The integrated vulnerability map showed that the very high and high vulnerability subareas were formed for reasons of highest or higher infiltration amount of precipitation (I), worst or worse protective cover (P), most complex type of land use (L), poor water abundance (A) and over groundwater exploitation (E). Sensitivity analyses showed that infiltration amount of precipitation (I) is the most sensitive factor affecting groundwater vulnerability in the case study. In short, APLIE method was applicable to assess the karst-phreatic vulnerability in the study area with readily available hydrogeological and environment geological data. Hence, the groundwater vulnerability mapping is a promising tool for sensible groundwater resource management and land use planning, which contributes to the development of human survival and sustainable development of groundwater.