Intrinsic groundwater vulnerability assessment, comparison of different methodologies and validation


ŞENER E.

ARABIAN JOURNAL OF GEOSCIENCES, vol.14, no.19, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 19
  • Publication Date: 2021
  • Doi Number: 10.1007/s12517-021-08338-y
  • Title of Journal : ARABIAN JOURNAL OF GEOSCIENCES
  • Keywords: Groundwater vulnerability, DRASTIC, GOD, Aksehir Lake, Turkey, AQUIFER VULNERABILITY, DRASTIC METHOD, POLLUTION VULNERABILITY, COASTAL REGION, GIS, MODEL, PLAIN

Abstract

Several methods were proposed and applied by different researchers to determine the groundwater vulnerability to pollutants. These methods have some advantages and disadvantages and the application of different methods and evaluation of the results increase the reliability of studies. In the present study, the DRASTIC and GOD methods were selected to assess the intrinsic groundwater vulnerability to pollution around Aksehir Lake within the Akarcay Basin, Turkey. Two intrinsic groundwater vulnerability maps were compared with graphical and statistical analyses such as correlation and simple linear regression. In addition, the vulnerability maps were checked against groundwater nitrate concentrations. Single-parameter sensitivity analysis was performed for the DRASTIC parameters and it was found that aquifer media (16.96%) and impact of the vadose zone (14.70%) have higher effective weights than the other parameters. Generally, both vulnerability maps prepared for the study area provide similar results and GOD vulnerability index and DRASTIC vulnerability index values have high positive correlation (r= 0.84). The alluvium regions around and also along the shore of the lake have high pollution potential in the region. However, according to the R-2 values obtained with simple linear regression analysis, intrinsic groundwater vulnerability prepared using the DRASTIC method has higher accuracy than that prepared using the GOD method. This result is also supported by groundwater nitrate concentrations.