EPA Document Focuses On Use Of Groundwater Geohydrology Computer Program

On Dec. 6, EPA's Web site announced the release of a document that introduces, through a case study, the use of the groundwater geohydrology computer program WhAEM for Microsoft Windows (32-bit), or WhAEM2000.

WhAEM2000 is a public domain, groundwater flow model designed to facilitate capture zone delineation and protection area mapping in support of the state's and tribe's Wellhead Protection Programs (WHPP) and Source Water Assessment Planning (SWAP) for public water well supplies in the United States National Exposure Research Laboratory (NERL -- http://www.epa.gov/nerl/index.html).

Program operation and modeling practice are covered in a series of progressively more complex representations of a well field tapping a glacial outwash aquifer. WhAEM2000 provides an interactive computer environment for design of protection areas based on simple WHPAs (e.g., radius methods, well in uniform flow solutions), and geohydrologic modeling methods. Protection areas are designed and overlaid upon U.S. Geological Survey Digital Line Graph (DLG), Digital Raster Graphic (DRG) or other electronic base maps. Geohydrologic modeling for steady pumping wells, including the influence of hydrological boundaries, such as rivers, recharge, no-flow boundaries, and in homogeneity zones, is accomplished using the analytic element method. Reverse gradient tracelines of known residence time emanating from the pumping center are used to delineate the capture zones.

WhAEM2000 has import and export utilities for DXF files and Shape files. WhAEM2000 has on-line help and tutorials. Install scripts and base maps are available for download from the EPA Center for Exposure Assessment Modeling Web site (http://www.epa.gov/athens/software/whaem/index.html).

The document, Working with WhAEM2000 - Capture Zone Delineation for a City Wellfield in a Valley Fill Glacial Outwash Aquifer Supporting Wellhead Protection, can be accessed at http://www.epa.gov/athens/publications/reports/Kraemer%20600%20R05%20151%20WhAEM2000.pdf.

This article originally appeared in the 12/01/2005 issue of Environmental Protection.

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