GROUNDWATER VULNERABILITY

A DRASTIC Model Based on GIS for the Assessment of Shallow Aquifer's Groundwater Vulnerability



A DRASTIC Model Based on GIS for the Assessment of Shallow Aquifer's Groundwater Vulnerability

Abstract

Hydrological responses have been used for determining the surface water quality. These responses vary geographically. The processes of movement of groundwater and pollutant transportation of the sub- surface water are primarily influenced by sub-surface hydrologic environment. In this age of industrialization, groundwater is highly vulnerable to pollution, and the maps of aquifer vulnerability have been getting wide popularity. Groundwater is not only considered as the main source of drinking water, but is also the basis of human and economic activities. Some of the real and potential sources relying on ground water consumption include industry, household and agriculture. In order to continue execution of all these activities, there is an emerging need to study the groundwater pollution factors. In this paper, our main objective is to determine the groundwater vulnerable zones in the city, which is one of the thickly populated cities of the country, and has been suffering from the issues of groundwater pollution. In addition to the city, we also include the surrounding areas in our analysis. We use DRASTIC model based on advanced information system, i.e.; Geographical Information System (GIS) for determining the level of water pollution. The model depends on seven data layers for collecting inputs. The seven letters of the model DRASTIC are named after the initials of the layers; D: water Depth, R: total Recharge, A: Aquifer media, S: Soil media, T: Topography, I: vadose zone's Impact, and C: hydraulic Conductivity. The pollution level of groundwater in shallow aquifers was determined by using the GIS software Arcview 3.2 and ILWIS, version 3.0. The study revealed facts that approximately 80% of the groundwater in the city is highly vulnerable to pollution. This high level of pollution raises serious concerns for the 0.8 million population of the city. The advanced technologies such as GIS tools served as a vital component of this research, and provided considerable help in data collection and analysis stages. On the basis of research done, the software tools are recommended to be used by authorities for better and improved management of groundwater resources.

Keywords: Groundwater, Vulnerability, GIS, DRASTIC model.

Introduction

The issues related to groundwater often deals with the environmental concerns such as water pollution and its impact on water quality degradation. The groundwater pollution has become a most serious issue, as this water serves as the main source of drinking water, and is also used for various activities. For example, the domestic water usage completely relies on the groundwater. As the industrialization and population growth have been significantly increased over past few decades, greater amounts of household, chemical and industrial waste products are being discharged into the groundwater of the cities. Hence the increased waste materials can be considered as the major factor for polluting the groundwater in shallow aquifers of all the major cities of the world. As with all the countries, water pollution poses a serious ...