A fully coupled GIS weighted multi-criteria decision making approach (MCDM) framework was designed to identify and prioritize areas for monitoring aquifer hydraulic heads within the Victoria County Groundwater Conservation District, TX. The criteria address salient hydrogeological factors including groundwater variability, recharge, surface water groundwater interactions and groundwater fluxes across district boundaries. Texas water statutes require groundwater conservation districts to quantify these factors and utilize them to manage aquifers. The ratings for these criteria were obtained using a variety of digital data in conjunction with concepts of entropy theory and regionalized variable analysis. A stakeholder survey instrument was used to prioritize and weigh these criteria. A monitoring priority index (MPI), whose value theoretically ranges between 0 - 1 was computed as a weighted average of six mutually exclusive criteria. The MPI value was seen to range between 0.2 ~ 0.6 within the study area. Lower values of MPI indicate areas where current level of monitoring is adequate and areas with higher MPI point to locations where additional monitoring is necessary. In particular, monitoring along district boundaries, particularly along the western and southern sections was recommended based on the analysis. The developed methodology was seen to provide a transparent and simple to use approach to identify and prioritize areas within the district for the purposes of groundwater monitoring. In addition, a statistical power analysis was carried out independently to identify the required number of wells to detect a pre-specified change of 1 ft of drawdown in five years. The results of the power analysis was combined with GIS-MCDM to configure the network (i.e., identify the number of wells within the network and their spatial locations). The proposed framework demonstrates the utility of GIS in facilitating a scientifically-credible and stakeholder-driven approach for establishing regional-scale groundwater monitoring networks.
展开▼
