Tritium in liquid waste released from damaged storage containers or generated through the leaching of percolating meteoric water can migrate in both the liquid and vapor phases. Migration through layers with large pore sizes can occur in both lateral and vertical directions based on soil, hydrologic conditions and established thermal and pressure gradients. Basin alluvial fill is typically stratified, and zones of stratified materials with higher porosity could become confined conduits for tritium vapor. It is believed that such a process may be occurring at the Beatty radioactive waste disposal site, as native plants located several hundred meters from a known release have leaf level tritium activities above background. This work seeks to quantify thermal and water gradients in desert soils associated with creosote at the Nevada Test Site and determine what influence they have on vapor movement of tritium and determine the extent of tritium uptake by creosote associated with tritium in the soil vapor phase. Vapor movement and plant uptake are assessed using the TOUGH2 model, a multi-dimensional numerical code for simulating the coupled transport of water, vapor, non-condensable gas, and heat in porous and fractured media. To the extent possible, we use known hydraulic properties, hydraulic conditions, and layering sequences from the field study location. The modeling is carried out to simulate the field observations of tritium concentrations in porous material adjacent to the plants. This controlled study of dispersive and diffusive transport of tritium, and the use of plants as sentinels, could provide a more process-based explanation of this phenomenon, and hence improve the predictions of future potential transport from the disposal areas to surrounding soil. The understanding of those conditions that most affect tritium vapor migration could also reduce the time needed to identify when tritium release into surrounding soil has occurred.