3-DIMENSIONAL SCALE-MODEL OF GROUNDWATER SOLUTE TRANSPORT

A three-dimensional scale model was designed and built to simulate ground-water solute transport at the Savannah River Site in east-central South Carolina. The site is 0.75 km2 in surface area, and averages 35 m in depth. Liquid wastes have been continuously disposed of on the site for about 30 years. The model was built to an undistorted geometric length scale of 1/500. Model materials of sand, cement, and water, blended in varying proportions to achieve different hydraulic conductivities and effective porosities, allowed simulation of four geologic formations in the prototype. The organic dye Rhodamine 6G was used to represent the prototype solute, tritium. Using scaling laws developed for advection, dispersion, chemical interaction, and making adjustments for the radioactive decay of the tritium, the model plume favorably compared with the carefully mapped plume at the prototype. Capillary forces were not scaled. The writers cautiously recommend more widespread use of scale models in ground-water research. © ASCE.