A GIS-based DRASTIC Model for Assessing Groundwater Quality Vulnerability: Case Study of Surat and its Surroundings

Abstract

Groundwater is one of the most important water resources, with varying quality and quantity. It is extremely difficult to recycle contaminated groundwater. As a result, protecting groundwater from contamination is critical. Industrial and municipal wastes, agricultural contamination owing to pesticides and chemical hazards, seawater intrusion in coastal areas, and other factors damage groundwater. The objective of the study is to assess the groundwater quality vulnerability using the DRASTIC model with a geoinformatics approach in Surat and its surroundings. Depth of water, Net recharge, Aquifer, Soil, Topography, Impact of the vadose zone, and Hydraulic conductivity are the parameters to be considered for assessing the vulnerability using the DRASTIC model. In this study, all parameters are weighted by conventional weights. The study shows that almost 53.46% of the total study area is under moderate vulnerability, and 46.54% of the area is under high vulnerability. Olpad, Kamrej, chorasi, Surat city, and the lower part of Bardoli talukas are coming under high vulnerability, whereas other parts are coming under moderate vulnerability. It is observed that the parameters like net recharge, impact of the vadose zone, depth to the water table, and aquifer media are largely affected by high vulnerability. The study delineates groundwater vulnerability in the study area, which can help land-use policies and norms for activities connected to recharge and seepage concerning the current status of groundwater vulnerability and quality. This study helps policymakers and local authorities in taking protective measures for groundwater quality.

Application of the Weighted Arithmetic Water Quality Index in Assessing Groundwater Quality: A Case Study of the South Gujarat Region

“…SI i is the subindex of the ith parameter and i represents the number of parameters taken into consideration [5,27]. In Table 1, the ideal values and unit weights for the water quality variables and their standard values are shown [10,30].…”

“…Groundwater is typically used by farmers to irrigate their crops more frequently than other sources, such as surface water [3]. Groundwater quality and quantity are significantly impacted by both natural and man-made activities [4,5].…”

Evaluation of Groundwater Vulnerability of Yishu River Basin Based on DRASTIC-GIS Model

“…The size of the standard grids was decided after considering the spatial distribution of each item, the characteristics of the changes, and the accuracy of the collected data so as to delineate the vulnerability zones in the YRB. The DRASTIC model, a well-established framework for assessing regional groundwater pollution potential, quantifies the impact of each assessment index on groundwater pollution prevention through scoring values [33,34]. Each evaluation index is classified into grades, and its score is determined based on its influence on groundwater pollution.…”

“…These indexes are the groundwater depth (D), net recharge of aquifers (R), aquifer media (A), soil type (S), topography (T), medium of seepage zone (I), and hydraulic conductivity of aquifer (C). Each of these indicators represents a specific hydrogeological condition that contributes to the overall vulnerability of groundwater [33,34,36].…”

“…In the context of aquifer vulnerability evaluation, the vector or grid units in GIS graphics can correspond to the evaluation units employed in evaluation methods [26,32]. Furthermore, the classification and overlay analysis process of GIS software aligns precisely with the factor scoring process and weighted sum analysis of diverse factors in evaluating groundwater vulnerability [33,34]. The utilization of GIS technology's attribute database and spatial overlay analysis for evaluating the vulnerability of aquifers proves to be both straightforward and prevalent.…”