A Modified AVI Model for Groundwater Vulnerability Mapping: Case Studies in Southern Italy

Daniela Ducci,Mariangela Sellerino

doi:10.3390/w14020248

Abstract

Many methods for evaluating the aquifer’s vulnerability to pollution have been developed in the past four decades by using geographic information system (GIS) tools. However, even if the aquifer vulnerability concept is well defined and the methods have been constantly tested and compared, the problem of the choice of the best “standard” method remains. To meet these objectives, aquifer vulnerability maps are of crucial importance. The choice of method depends on several factors, including the scale of the project, the hydrogeological characteristics of the area, and data availability. Among the many methods, the AVI (Aquifer Vulnerability Index) method has been widely used as it considers only two physical parameters. The AVI Index represents the hydraulic resistance of an aquifer to vertical flow, as a ratio between the thickness of each sedimentary unit above the uppermost aquifer (D, length), and the estimated hydraulic conductivity (K, length/time) of each of these layers. The AVI Index has a time dimension and is divided into five classes. In order to avoid a widespread presence of the higher vulnerability classes, especially in shallow aquifers, the AVI classification has been modified using statistical methods. The study reports the application of the modified AVI method for groundwater pollution vulnerability, in three different areas of southern Italy, highlighting the limitations of the method in alluvial aquifers and the differences with other methods.

Highlights

Groundwater, accounting for over 97% of all freshwater available on earth, is a key factor for human life, but it is a vulnerable resource
The classification of the indexes/values in vulnerability degree in function of the vulnerability method is in Table 1: vulnerability indexes have been classified in a range of five “vulnerability degrees”, from “very high” to “very low
This study study applied pollution vulnerability in in three different areas of southern

Summary

Introduction

Groundwater, accounting for over 97% of all freshwater available on earth, is a key factor for human life, but it is a vulnerable resource. The worsening of the groundwater quality is due to agricultural, domestic, and industrial activities. Are generally spread on the ground’s surface, and occasionally, especially in the past and in illegal practices, directly introduced into the aquifer, e.g., by wells. The slow movement of groundwater through the vadose zone and aquifers determines that the pollution, generated by agricultural, industrial, and other anthropogenic activities (sometimes decades ago!), can affect the current groundwater quality and this can continue into the future. In order to restore groundwater quality, large economic resources and efforts are required; groundwater remediation techniques are available and have been continuously implemented in the past years, but they are costly and only applicable to small areas

Methods

Results

Conclusion