Hanford Site ground-water model: Geographic information system linkages and model enhancements, FY 1993.

摘要

Models of the unconfined aquifer are important tools that are used to (1) identify and quantify existing, emerging, or potential ground-water quality problems, (2) predict changes in ground-water flow and contaminant transport as waste-water discharge operations change, and (3) assess the potential for contaminants to migrate from the US Department of Energy's Hanford Site through the ground water. Formerly, most of the numerical models developed at the Hanford Site were two-dimensional. However, contaminant concentrations cannot be accurately predicted with a two-dimensional model, which assumes a constant vertical distribution of contaminants in the aquifer. Development of two- and three-dimensional models of ground-water flow based on the Coupled Fluid, Energy, and Solute Transport (CFEST) code began in the mid- 1980s. The CFEST code was selected because of its ability to simulate both ground-water flow and contaminant transport. Physical processes that can be modeled by CFEST include aquifer geometry, heterogeneity, boundary conditions, and initial conditions. The CFEST ground-water modeling library has been integrated with the commercially available geographic information system (GIS) ARC/INFO. The display and analysis capabilities of a GIS are well suited to the size and diversity of databases being generated at the Hanford Site. The ability to visually inspect large databases through a graphical analysis tool provides a stable foundation for site assessments and ground-water modeling studies. Any ground-water flow model being used by an ongoing project should be continually updated and refined to reflect the most current knowledge of the system. The two-dimensional ground-water flow model being used in support of the Ground-Water Surveillance Project has recently been updated and enhanced. One major enhancement was the extension of the model area to include North Richland.