Vertical tritium transport from the shallow unsaturated zone to the atmosphere, Amargosa Desert Research Site, Nevada
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62h0052067 20140224103001.0 cr an |||||||| 131031s2007 a fsbm |000|0 eng | 1446436 9780549166047(e-book) : CNY371.35 NGL eng NGL a494.4 Garcia, Christina Amanda. Vertical tritium transport from the shallow unsaturated zone to the atmosphere, Amargosa Desert Research Site, Nevada [electronic resource] / Christina Amanda Garcia. 2007. 1 online resource. Description based on online resource; title from title page (viewed Oct. 31, 2013) Thesis (M.S.)--University of Nevada, Reno.bHydrogeology, 2007. Includes bibliographical references. Understanding the impact of desert vegetation on tritium transport and fate is essential when considering low-level radioactive waste (LLRW) isolation in the arid western U.S. This study uses field data to estimate the magnitude and spatio-temporal variability of tritium transport from the shallow unsaturated zone to the atmosphere adjacent to a LLRW facility and numerical modeling to clarify tritium transport mechanisms beneath desert vegetation. A 2-year tritiated-water-vapor (HTOg) mass of 0.0013 g was released within the study area and quantified using evaporation, transpiration, and HTO g concentrations in plants and shallow soil. Spatial tritium flux variability was predominantly driven by proximity to HTOg source areas. Temporal variability was controlled by the subsurface HTOg concentration gradient, concentration dilution from precipitation, and depth of maximum root-water extraction. Numerical simulation results indicate that root uptake by desert vegetation can lead to upward water movement below the root zone. This, in turn, can increase the upward HTOg flux. Amplified upward fluxes prevent long-term shallow subsurface moisture accumulation, limiting moisture penetration below the root zone and the potential for groundwater contamination. Groundwater flow ; Groundwater flow Mathematical models. Amargosa Desert (Calif. and Nev.) Electronic dissertations local. aInternet resource. aCN b010001 http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=%2fcMaS2MdbgY%3d 010001 Bs2909 rCNY371.35 ; h1 bs1401