Assessment of Aquifer Vulnerability Based on GIS and ARCGIS Methods: A Case Study of the Sana’a Basin (Yemen)

Yahia Alwathaf,Bouabid El Mansouri

doi:10.4236/jwarp.2011.312094

Abstract

Groundwater is the main source of water in arid and semi-arid regions. Therefore, pollution of groundwater is a major issue because aquifers and the contained groundwater are inherently susceptible to contamination from wastewater and agricultural activities. Aquifer vulnerability has been assessed in the Sana’a basin using the DRASTIC method, based on a Geographic Information System (GIS). The DRASTIC model uses seven environmental parameters (Depth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity) to characterize the hydrogeological setting and evaluate aquifer vulnerability. A regional scale aquifer vulnerability map of the basin was prepared using overlay analysis with the aid of GIS. A DRASTIC vulnerability map, verified by data of nitrate in groundwater, shows that the defined areas are compatible with land-use data. It is concluded that 6.4% of the basin area is highly vulnerable and urgent pollution-preventions measures should be taken for every kind of relevant activity within the whole basin.

Highlights

Nowadays, groundwater resources play an important role in meeting demands on water supply because of regional climate change and scanty surface water source or their unsuitability
The main aim of this study is to evaluate the aquifer vulnerability in the basin and determine the degree of contamination of Sana’a basin using the DRASTIC model based on Geographic Information System (GIS)
Seven parameter maps were prepared in a GIS environment and the vulnerability classification of the basin was performed using GIS technique

Summary

Introduction

Groundwater resources play an important role in meeting demands on water supply because of regional climate change and scanty surface water source or their unsuitability. Leaching of various pollutants through the unsaturated zone and groundwater zone gives rise to contamination in these zones. These processes vary from one location to another. A thorough overview of existing methods is given in [7] and in [8]. These methods have been mainly applied to groundwater protection in porous aquifers, except the EPIK [9,10], PI [11], and COP [12] methods which are developed for the assessment of vulnerability in karstic areas

Objectives

Methods

Results

Conclusion