Evaluation of Groundwater Vulnerability and Sustainability Using GIS

Abstract

Knowledge of spatial and temporal variability in groundwater quality is necessary to validate and compliment aquifer vulnerability estimates that have become important elements for sound resources planning. Here, to evaluate vulnerability of the unconfined groundwater, we assessed intrinsic aquifer vulnerability of the alluvial Nasuno Basin of Tochigi Prefecture, Japan, using the DRASTIC model. We also used a groundwater quality index, which synthesizes different available water quality data to delineate spatial variability in the overall groundwater quality. Data are mapped spatially in GIS (Geographic Information System) and the results integrated to assess the pollution risk and degree of sustainability of water quality in the basin. Although the study area was characterized by high to very high aquifer vulnerability, the groundwater quality was generally good with only limited zones showing relatively lower groundwater quality: the vicinity of the Naka and Houki Rivers and the lower part of the basin. This information clearly reflects the greater role of anthropogenic impacts (agricultural and urban activities) on the groundwater quality of the area.