engleski

Specific vulnerability assessment in karst system, example of Jadro and Žrnovnica springs catchment area, Croatia

Aquifer vulnerability to contamination assessment is proved to be avery frequent and valuable tool for evaluating the threats which contaminant load poses to groundwater quality, as well as vulnerability maps, which can be used as a background for land-use planning and as an additional tool in groundwater protection. According to the COST Action 620 “Vulnerability and risk mapping for the protection of carbonate (karst) aquifers” there are two types of vulnerability – intrinsic, which deals only with intrinsic characteristics of aquifers, and specific, which takes into account the type of contaminant or group of contaminants, their characteristics, as well as retardation and degradation process which can occur in the interaction between contaminants and overlaying layers. The Study area includes the Jadro and Žrnovnica springs catchment area which is located near Split, central Dalmatia, Croatia. Both springs are a very important source of drinking water for more than 300 000 local inhabitants. The catchment area, approximately 560 km2 wide, is predominantly composed of permeable carbonate rocks, which makes it even more difficult to protect groundwater resources. Recent studies have shown that there has been a trend of deterioration in the quality of spring water due to economic expansion in the catchment area and lack of appropriate protection of drinking water sources. The changes in water quality are not alarming, but a positive trend of increasing pollution, even below MAC limits, can indicate the existing problems, as well as encourage finding solutions to improve the water quality In this paper, specific vulnerability will be assessed using COP method in addition to definition of specific parameters S for nitrates, some heavy metals and indicators of microbiological contamination. The results of the specific vulnerability will be compared with the hazard analysis which has already been made for the study area in order to assess the level of anthropogenic impact. The measurement of concentration of some contamination indicators in some parts of the catchment area will be used to evaluate the comparison results. Such a comprehensive study can be used in defining the measures of protection or remediation to preserve the quality and quantity of groundwater as an essential source of drinking water from karst areas.

groundwater quality, contamination, specific vulnerability, COP, Jadro and Žrnovnica

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