DRASTIC modification to map groundwater vulnerability to pollution using nitrate measurements in agricultural areas

Abstract

The main purpose of using DRASTIC model is to map the groundwater susceptibility to pollution in different areas. However, this method has been used in different places without any modification; it cannot be taken into account the effects of pollution type and characteristics. This is the reason why this methods needs to be standardized and approved for the aquifer and particular type of pollution. In this research study, through the correction of the rates of DRASTIC parameters, we can assess the potential of vulnerability to pollution more effectively with accuracy. The new rates were calculated by identifying the relationship between each parameter to the concentration of nitrate in groundwater. The methodology that has been used for the research study was implemented in Astaneh aquifer reside in north part of Iran. Nitrate concentration from underground wells were tested and analyzed in thirteen different locations. The measured nitrate concentrations were utilized to associate and link the pollution in aquifer to DRASTIC index. The method of correlation i.e. Pearson correlation was applied to find the relationship between the index and measured pollution in each section and so, to change the rates. The results of the study reveal that the changed DRASTIC is better than the traditional method for nonpoint source pollution particularly in agricultural areas. Regression coefficient results showed that the changed method between vulnerability index and nitrate concentration was recorded as 64 percent as compared to 23 percent which was recorded before modification.

DRASTIC modification to map groundwater vulnerability to pollution using nitrate measurements in agricultural areas

Introduction

Groundwater is considered as the most important resources widely used in different parts of the world particularly in those areas which are located in arid and semi-arid regions. This is the reason why water quality is becoming more important in effectively managing groundwater. Usually Aquifers are loose, thin and highly leaky and therefore, enormously vulnerable to pollution from the ways of surface. The potential for groundwater to be polluted as a result of human action performed at or near the surface that has been considered as a leading managers of this major resource in recent years in order to implement the policy of prevention.

The ability or potential for contaminants to obtain a specified position in the underground system after the beginning at some places above the top most aquifer is known as groundwater vulnerability (National Research Center, 1993). The assessment of vulnerability must be based on scientific, accurate evidence and objective. Nowadays, there are different methods that have been introduced to estimate the accurate groundwater vulnerability. It has been observed that in most of the cases, these procedures are called as analytical tools that always intended to correlate groundwater contamination to land activities. These assessment processes and procedures are categorized in three different parts: process-based simulation models, statistical methods (Harbugh et al., 2000) and overlay and index methods.

Process-based models are generally involved large number of data and secondary information necessary to apply mathematical ...