Numerical modeling studies on the alternately pulsed infiltration and subsequent evaporation of water in a dry high desert alluvial soil

The concept of no liquid-phase migration of low-level radionuclides is extremely important for the U.S. Department of Energy, Nevada Operations Office (USDOE/NV) Low-Level Radioactive Waste Management Sites (RWMS) in Areas 3 and 5 of the Nevada Test Site (NTS). Each site location is situated in an area known for its dry conditions. A series of computer modeling problems were set up to study the effects of pulsing the desert surface with large amounts of water, followed by intense evaporative conditions. The pulsed-water scenarios were run using an in-house model, named {open_quotes}ODRECHB,{close_quotes} which is briefly described. ODRECHB is particularly adapted to model the dry desert alluvium and extreme evaporative conditions found at NTS. Comparable results were obtained using the well known Battelle NW code {open_quotes}UNSAT-H 2.0,{close_quotes} by Fayer and Jones. The realistic-to-overly conservative water applications to a bare soil surface did not cause water to infiltrate below ten meters. The results are shown on the accompanying video tape.