Assessment of groundwater salinisation risk using multivariate geostatistics

The risk assessment at regional scale requires modelling spatial variability of environmental variables. Traditional approach, based on estimating point environmental indicators, cannot be considered satisfactory for this purpose, because it does not take into account spatial dependence between variables. We propose the application of an approach to the problem of groundwater salinisation, in which multivariate geostatistics and GIS are combined to integrate primary information with exhaustive secondary information. The dataset consisted of 454 private wells used for irrigation and located in Apulia region (south Italy). Three variables were processed: concentration of chlorides and nitrates, as primary variables, and the distance from the coast, as auxiliary variable. The approach highlighted the widespread degradation of water resources in the Apulian groundwater. The maps of the global indicator allowed us to delineate the zones at high risk of groundwater contamination and also to identify those parameters most responsible for water degradation, so that a wiser management of water resources could be planned. This approach can be used as operational support to a wide range of activities and in decision making among several remediation alternatives.