Evaluation of a GIS-Based Integrated Vulnerability Risk Assessment for the Mancha Oriental System (SE Spain)

Abstract

It is widely recognized that groundwater-vulnerability maps are a useful tool for making decisions on designating pollution-vulnerable areas, in addition to being a requirement of European Directive 91/676/EEC. This study addressed the vulnerability of the Mancha Oriental System (MOS) to groundwater contamination with an integrated Generic and Agricultural DRASTIC model approach. In the MOS, groundwater is the sole water resource for a total population of about 275,000 inhabitants and for 1,000 km 2 of irrigated crops. DRASTIC vulnerability maps have been drawn up for two different years (1975 and 2002) in which the potentiometric surface has dropped dramatically (80 m in some areas) due to the considerable expansion of irrigated croplands. The quality of available resources has also deteriorated due to the agricultural practices and the discharge of wastewater effluents. Vulnerability maps are used to test the data on nitrate, sulphate, and chloride contents in groundwater in the Central and El Salobral-Los Llanos hydrogeologic domains of the MOS for 2002. Regardless of the method applied, the dramatic alteration in land use leads to a change in the DRASTIC index and vulnerability to groundwater contamination decreases for the study period. Vulnerability in the MOS increases in areas where the irrigation return flow is notable. The lack of a statistical correspondence between the DRASTIC index and the spatial distribution of nitrate, chloride, and sulphate contents and the distribution of the pollution load suggest that this method does not accurately assess the risk of the MOS to groundwater pollution.

A GIS-based quality assessment model for olive tree irrigation water in southern Spain

“…More complex models and GIS-based tools were previously used to assess quality in ground water (e.g. Moratalla et al, 2011) and irrigation water (Romanelli et al, 2012). However, the proposed model allows one to obtain maps for specific risks with a view to defining measures tailored to each risk and area, and also for different water sources (surface and ground).…”

Risco de intrusão salina e desenvolvimento sustentável: gestão integrada de água subterrâneas

“…Embora as águas superficiais sejam mais vulneráveis a esta poluição do que as águas subterrâneas, quando estas são contaminadas, não é fácil intervencionar-se para melhorar a sua qualidade (chenini et al, 2015). A vulnerabilidade de um sistema aquífero à poluição está relacionada com diversos aspetos, nomeadamente, com a litologia, a geometria do espaço em que está confinado e a hidrogeologia (chenini et al, 2015;Varol & Davraz, 2010;Moratalla et al, 2011). Quando se faz a avaliação da qualidade da água de um sistema aquífero, deve atender-se aos vários aspetos hidrogeológicos, isto é, à sua zona de recarga, ao seu caudal e aos usos do solo na região.…”

Evaluation of groundwater vulnerability to pollution using DRASTIC, composite DRASTIC, and nitrate vulnerability models

“…Preparing vulnerabilities or, in other words, vulnerability zoning is a powerful lowcost method yet, which in determining priority aquifers in terms of monitoring and care, selecting safe areas for urban development, agriculture and industry with minimal damage to groundwater, plays a key role that can help planners and managers protect groundwater. Vulnerability zoning is based on the idea that some areas are more sensitive to groundwater pollution than other areas (5). In fact, with the help of vulnerability maps, potentially dangerous groundwater activities can be placed in areas where groundwater aquifers are less threatened.…”