Optimal resizing of groundwater monitoring networks: a retrospective analysis of a reduced configuration

The redesign of environmental monitoring networks is a field rich of practical applications, in particular in light of recent EU environmental directives. When dealing with an existing monitoring network reduction, the easiest approach is to search for redundancies among the monitoring locations (clusters of locations) and to remove the most useless of them on the basis of the values of some quantitative parameter. This approach could lose some important features of the existing network, thus reducing its informative content. To avoid such a risk, the results of the network optimization should undergo a retrospective analysis capable to verify, by assessing some independent statistical indices, the acceptability of the reduced configuration with respect to specific managerial issues. The case study presented in this work focuses on the optimal downsizing of a groundwater monitoring network located in the Southern part of Italy. The MSANOS optimization software has been used to select the locations to remove from the existing network, with the goal to sustainably balance maintenance costs and information loss. The investigated case is of particular interest for both the critical issues of the considered resource and the recognized importance of the groundwater monitoring in the European Water Framework Directive.