The origin of elevated water levels in emplacement boreholes, Pahute Mesa, Nevada Test Site: A numerical study

Technical Report · Wed Dec 01 00:00:00 EST 1993

DOI:https://doi.org/10.2172/10165462· OSTI ID:10165462

Gardner, G G; Brikowski, T H

The origin of elevated water levels in emplacement boreholes at Pahute Mesa, Nevada Test Site, is uncertain. If the water is from naturally perched aquifers, then presumed ``above water table`` weapons tests may directly impact the groundwater quality. The purpose of this study is to determine the probable source of the elevated water in boreholes by comparing modeled seepage of infiltrated drilling fluids, and the seepage from a simulated naturally perched aquifer with the observed water level history. In the model, large volumes of water are infiltrated, yet return flow of fluids back into the hole stops within three days after the end of drilling and is insufficient to produce observed standing water. Return flow is limited for two reasons: (1) the volume of the saturated rock next to the borehole is small; (2) pressure head gradient direct unsaturated flow away from the borehole. Simulation of seepage from a naturally perched aquifer readily reproduces the observed water levels.

• Research Organization: Nevada Univ., Reno, NV (United States). Desert Research Inst.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC08-90NV10845
• OSTI ID: 10165462
• Report Number(s): DOE/NV/10845-44; ON: DE94015056; BR: 35DB01025/35EW31209; TRN: AHC29415%%39
• Resource Relation: Other Information: PBD: Dec 1993
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
NEVADA TEST SITE
BOREHOLES
WATER INFLUX
ORIGIN
HYDROLOGY
WATER TABLES
FLOW MODELS
GEOLOGIC MODELS
WELL DRILLING
STRATIGRAPHY
SENSITIVITY ANALYSIS
COMPILED DATA
EXPERIMENTAL DATA
540250
450200
SITE RESOURCE AND USE STUDIES
NUCLEAR EXPLOSIONS AND EXPLOSIVES