GROUNDWATER SOLUTE TRANSPORT MODELING USING A THREE-DIMENSIONAL SCALED MODEL

Scaled models have been rarely used as predictive tools for porous media flow problems; the few so employed were mostly one-dimensional, with the results being generally favorable, particularly for certain flow phenomena (e.g., water infiltration into soil; miscible fluid drives in oil reservoirs). In fact their use may have been prematurely eclipsed by the rapid conversion of modeling efforts into computer simulations which began in earnest 20 years ago, at about the time work on model scaling laws was beginning.; Scaled models are used extensively in current hydraulic research on sediment transport and solute dispersion in free surface flows (rivers, estuaries), but are neglected in current groundwater model research. Thus, an investigation was conducted to test the efficacy of a three-dimensional scaled model of solute transport in groundwater. No previous results from such a model have been reported.; Experiments performed on uniform scaled models indicated that some historical problems (e.g., construction and scaling difficulties; disproportionate capillary rise in model) were partly overcome by using simple model materials (sand, cement and water), by restricting model application to selective classes of problems, and by physically controlling the effect of the model capillary zone. Results from these tests were compared with mathematical models.; Model scaling laws were derived for groundwater solute transport and used to build a three-dimensional scaled model of a groundwater tritium plume in a prototype aquifer on the Savannah River Plant near Aiken, South Carolina. Model results compared favorably with field data and with a numerical model. Scaled models are recommended as a useful additional tool for prediction of groundwater solute transport.