Envision: Visualizing Water Quality from Geographically Distributed Wells

Understanding trends in ground water contaminant concentrations is complicated by the fact that ground water quality presents complex three-dimensional trends over multiple spatial scales. To address this issue we have developed a method to jointly display three-dimensional ground water quality and topographic data. This approach allows the user to: 1) identify local areas of elevated contaminant concentrations, 2) identify particular topographic features (river valleys, plateaus, etc) associated with elevated concentrations, 3) assess differences among aquifers and well use types, and 4) identify associations among different constituents. The approach used here links geospatially referenced concentration data with elevation data contained in Digital Terrain Elevation Data (DTED) files within an easyto-use MATLAB-based visualization system. The method was applied to visualize information on nitrate and arsenic occurrence in a national ground water quality database. The method shows that high arsenic is associated with the transition from plains to piedmont in New Jersey. Nitrate in Iowa is shown to be associated with shallow wells in the southeastern portion of the state. The approach developed here is compatible with any Microsoft Excel Spreadsheet database which follows specific format conventions.