AN OPTIMIZATION METHOD FOR MONITORING NETWORK DESIGN IN MULTILAYERED GROUNDWATER-FLOW SYSTEMS

Multiple migration pathways and the need to consider several potential siting horizons render the problem of groundwater monitoring network design a difficult task for three-dimensional systems. While the appli cation of quantitative simulation-based approaches for this problem is often impractical due to computational requirements, qualitative appr oaches can be ineffective because they are highly subjective and typic ally lack a set of well-defined criteria for locating sampling sites. An analytically based methodology developed in this paper integrates t he practical implementation aspects of a qualitative approach with a q uantitative analysis in deriving groundwater monitoring networks geare d toward early detection of migrating contaminant. Monitoring wells ar e located among sets of candidate nodes in each of several hydrostrati graphic intervals on the basis of contamination susceptibility. Suscep tibility is defined by nodal weights, which are derived on the basis o f the locations of sites relative to contaminant source boundaries and potential contaminant plumes. As is illustrated from the results of a case study application, derived monitoring network configurations exh ibit two key characteristics: (1) clustering of wells around outlets a t contaminant source boundaries and (2) coverage of vacant areas in mu ltiple siting horizons that are susceptible to contamination.