Intrinsic Vulnerability Mapping Research Articles

Source vulnerability mapping in carbonate (karst) aquifers by extension of the COP method: application to pilot sites

A step from resource to source vulnerability mapping is presented, based on the European COST Action 620 approach for karst groundwater protection. Guidelines on vulnerability assessment of the horizontal groundwater flow path within the karst saturated zone (K factor) are proposed. By integrating this into the previously existing COP method for intrinsic resource vulnerability mapping, adequate source protection can be assessed. The proposed “Karst saturated zone (K) factor” assessment considers groundwater travel time (t subfactor), connection and contribution to the source (r subfactor) and active conduit or fissured network (n subfactor). The extended COP method was applied in two carbonate aquifers in southern Spain with different geological, hydrogeological and climate settings. The results are coherent with previous research results of the studied areas. Moreover, they are consistent with the occasional groundwater contamination detected in one of the springs. On the other hand, an absence of contamination, despite high risk, justifies the lower degrees of vulnerability assigned to the sources surveyed. The source vulnerability maps obtained can thus be used as a basis for the delineation of protection zones.

Intrinsic vulnerability, hazard and risk mapping for karst aquifers: A case study

Groundwater from karst aquifers is among the most important resources of drinking water supply of the worldwide population. The European COST action 620 proposed a comprehensive approach to karst groundwater protection, comprising methods of intrinsic and specific vulnerability mapping, hazard and risk mapping. This paper presents the first application of all components of this European approach to the groundwater underlying the Ramallah district, a karst hydrogeology system in Palestine. The vulnerability maps which were developed can assist in the implementation of groundwater management strategies to prevent degradation of groundwater quality. Large areas in the case study area can be classified as low or very low risk area corresponding to the pollution sources due to the absence of hazards and also due to low vulnerabilities. These areas could consequently be interesting for future development as they are preferable in view of ground water protection.

A geophysical and geochemical approach for seawater intrusion assessment in the Acquedolci coastal aquifer (Northern Sicily)

Vertical electrical sounding (VES’) surveys and chemical analyses of groundwater have been executed in the coastal plain of Acquedolci (Northern Sicily), with the aim to circumscribe seawater intrusion phenomena. This urbanized area is representative of a more general problem interesting most of Mediterranean littoral areas, where intensive overdraft favors a heavy seawater intrusion through the coastline. Aquifer resistivity seems decisively to be conditioned by the chlorine and magnesium content in the main aquifer of the region. Schlumberger VES’, together with piezometric and chemical–physical information of groundwater, allowed us to perform hydrogeological and geophysical elaborations, to propose the occurrence of a relatively narrow belt marked by fresh–salt water mixing. In the considered plain, pollution risk studies have been already realized by authors with the proposal to identify—by parametric and synthetic zoning of significant hydrogeological elements—the most vulnerable sectors. In detail, an intrinsic vulnerability mapping has been already performed, applying the well-known SINTACS system. This paper intends to give—in this sector of Sicily—an example of integration of different methodologies, showing the role of geophysics to describe the degradation of aquifers on the whole as well as to assess their pollution risk better.

Assessment of intrinsic vulnerability to contamination for Gaza coastal aquifer, Palestine

Gaza coastal aquifer (GCA) is the major source of fresh water for the 1.5 million residents of Gaza Strip, Palestine. The aquifer is under deteriorating quality conditions mainly due to the excessive application of fertilizers. The intrinsic vulnerability of GCA to contamination was assessed using the well-known DRASTIC method. Detailed analysis of the intrinsic vulnerability map of GCA was carried out and did consider different relationships between the vulnerability indices and the on-ground nitrogen loadings and land use classes. In addition, correlation between vulnerability values and the nitrate concentrations in GCA was studied. Based on the vulnerability analysis, it was found that 10% and 13% of Gaza Strip area is under low and high vulnerability of groundwater contamination, respectively, while more than 77% of the area of Gaza Strip can be designated as an area of moderate vulnerability of groundwater contamination. It was found that the density of groundwater sampling wells for nitrate concentration is high for the moderate and high vulnerability zones. The highest first quartile, median, mean, and third quartile of nitrate concentrations are reported in the high vulnerability zones. Results of sensitivity analysis show a high sensitivity of the high vulnerability index to the depth to water table.

Karst groundwater protection: First application of a Pan-European Approach to vulnerability, hazard and risk mapping in the Sierra de Líbar (Southern Spain)

The European COST action 620 proposed a comprehensive approach to karst groundwater protection, comprising methods of intrinsic and specific vulnerability mapping, validation of vulnerability maps, hazard and risk mapping. This paper presents the first application of all components of this Pan-European Approach to the Sierra de Líbar, a karst hydrogeology system in Andalusia, Spain. The intrinsic vulnerability maps take into account the hydrogeological characteristics of the area but are independent from specific contaminant properties. Two specific vulnerability maps were prepared for faecal coliforms and BTEX. These maps take into account the specific properties of these two groups of contaminants and their interaction with the karst hydrogeological system. The vulnerability assessment was validated by means of tracing tests, hydrological, hydrochemical and isotope methods. The hazard map shows the localization of potential contamination sources resulting from human activities, and evaluates those according to their dangerousness. The risk of groundwater contamination depends on the hazards and the vulnerability of the aquifer system. The risk map for the Sierra de Líbar was thus created by overlaying the hazard and vulnerability maps.

Validation of an intrinsic groundwater pollution vulnerability methodology using a national nitrate database

The importance of groundwater for potable supply, and the many sources of anthropogenic contamination, has led to the development of intrinsic groundwater vulnerability mapping. An Analysis of Co-Variance and Analysis of Variance are used to validate the extensively applied UK methodology, based upon nitrate concentrations from 1,108 boreholes throughout England and Wales. These largely confirm the current aquifer and soil leaching potential classifications and demonstrate the benefits of combining soil and low permeability drift information. European legislation such as the Water Framework Directive will require more dynamic assessments of pollutant risk to groundwater. These results demonstrate that a number of improvements are required to future intrinsic groundwater vulnerability methodologies. The vertical succession of geological units must be included, so that non-aquifers can be zoned in the same way as aquifers for water supply purposes, while at the same time recognising their role in influencing the quality of groundwater in deeper aquifers. Classifications within intrinsic vulnerability methodologies should be based upon defined diagnostic properties rather than expert judgement. Finally the incorporation into groundwater vulnerability methodologies of preferential flow in relation to geological deposits, soil type and land management practices represents a significant, but important, future challenge.

Risk assessment of earth fractures by constructing an intrinsic vulnerability map, a specific vulnerability map, and a hazard map, using Yuci City, Shanxi, China as an example

Risk assessment of earth fracture hazards is particularly useful for regulatory, managerial, and decision-making purposes at all levels of government. A “three-map” method that includes intrinsic vulnerability, specific vulnerability, and hazard maps is developed to assess the earth fracture hazards in Yuci City, Shanxi, China. The intrinsic (natural) vulnerability map is based on the assessment of various natural factors by coupling the technologies of a Geographical Information System (GIS) to an Artificial Neural Network (ANN). The specific vulnerability map is generated by coupling the technologies of a GIS and an Analytical Hierarchy Process (AHP). According to the overlapping principles of multiple geo-information systems, the hazard map is therefore defined by overlapping the intrinsic and specific vulnerability maps using a spatial-operation function in the GIS. Unlike the intrinsic vulnerability map, the hazard map takes into account human activities and the importance of the area to be assessed. The proposed “three-map” approach is not only scientifically valuable, but provides a more realistic assessment of earth fracture hazards as well.

Using A GIS Approach For Setting Up A CoastalAlluvial Aquifer Intrinsic Vulnerability Map

This paper presents the application of a Geographic Information System for the setting up of an intrinsic vulnerability map of the 85 km extended Capoterra Plain coastal alluvial multilayered aquifer (Southern Sardinia Italy). The aquifer intrinsic vulnerability assessment was developed using the point count system model SINTACS 4.0 implemented using the Geographic Information System ARC/INFO. The final product is represented by a 1 : 25.000 scale aquifer intrinsic vulnerability map. This map was conceived to be an instrument for assisting local planners, managers and administrators in the task of evaluating the relative vulnerability of areas to groundwater contamination from various sources of pollution and it will be useful for developing programming, managing and protecting strategies of groundwater and environmental resources of the Capoterra Plain coastal area.