The purpose of this project was to develop the numerical tools to study the flow and water quality problems associated with underground coal gasification (UCG) burns. If this new technology of energy extraction is to become viable and widespread, then the environmental consequences have to be studied, predicted and managed. One of the ways of doing this is to use numerical modeling of flow and water quality to assess the environmental impact after the burns have been completed. An environmental manager would like to know the distribution and location of the contaminant plume as a function of time over a given time span (say 20 years). These numerical tools will be useful to the manager faced with such problems. At the end of the burn, a cavity is formed which could be considered empty and dry. The water from the surrounding coal seam begins to seep in and the water level in the cavity begins to rise, as in a well. The permeability in the cavity will be very large and porosity of the rubble in the cavity will be close to unity. Conditions in the cavity will be unconfined until the water fills the cavity and makes the flow confined. In this confined condition, the permeability will remain large; however, the storage coefficient will be somewhat greater than the value it had during pre-burn conditions. After the cavity is full, a stage will be reached when flow begins to occur out of the cavity. Before this stage, water flows into the cavity and the contaminated water stays in the cavity. After this stage, the water that leaves the cavity is contaminated. This contamination is then advected, dispersed, and decayed and sorbed in the coal seam. If all of these parameters are known, then numerical modeling will predict the location and magnitude of the pollutant plume at any future time. This report describes the numerical models developed to study this phenomenon.