Author: Ronald Lee Hershey
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 40

Get Book Here

Book Description

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 15

Get Book Here

Book Description
Periodically, water has been observed in emplacement boreholes drilled for underground testing of nuclear weapons at Pahute Mesa, Nevada Test Site, and is often at levels elevated above the predicted local water table. Water which may provide a means to transport residual radionuclides away from weapon tests may originate as fluids introduced during drilling, from naturally perched groundwater draining into the borehole, or from penetration of the local groundwater table. Lithium-bromide (Li-Br) tracer is being used to evaluate both the origin and movement of these borehole waters. The drilling fluid used to drill the final 100 meters of borehole U-19bh was chemically labeled with LiBr tracer. Lack of significant increase in borehole Br inventory over time indicates that standing water in U-9bh is not returned drilling fluid. Possible sources for the standing water are drilling fluid infiltrated above the bottom 100 in or natural water from a perched or shallower-than-expected saturated zone. The minimum detectable Darcy velocity of water passing through U-19bh is 0.3 m/yr. Borehole U-19bk has a water level approximately 50 in above the predicted pre-drilling water level. Initial water samples were collected from U-19bk to characterize the borehole water quality prior to adding the tracer. The major-ion analytical results of U-19bk along with historical water quality analyses of Water Well 20 and water well UE-19c show that all three waters are similar in character and therefore the water in U-19bk may be either residual drilling fluids originating from Water Well 20 and UE-19c or naturally occurring Pahute Mesa groundwater. LiBr tracer was added to the U-19bk borehole and samples for tracer analysis were collected one month later. For the one month period, no detectable loss of Br was observed. Over this short time period, the minimum detectable Darcy velocity is 10.6 m/yr.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 25

Get Book Here

Book Description
The presence of standing water well above the predicted water table in emplacement boreholes on Pahute Mesa has been a recurring phenomenon at the Nevada Test Site (NTS). If these levels represent naturally perched aquifers, they may indicate a radionuclide migration hazard. In any case, they can pose engineering problems in the performance of underground nuclear tests. The origin of these elevated waters is uncertain. Large volumes of water are introduced during emplacement drilling, providing ample source for artificially perched water, yet elevated water levels can remain constant for years, suggesting a natural origin instead. In an effort to address the issue of unexpected standing water in emplacement boreholes, three different sites were investigated in Area 19 on Pahute Mesa by Desert Research Institute (DRI) staff from 1990-93. These sites were U-19az, U-19ba, and U-19bh. As of this writing, U-19bh remains available for access; however, nuclear tests were conducted at the former two locations subsequent to this investigations. The experiments are discussed in chronological order. Taken together, the experiments indicate that standing water in Pahute Mesa emplacement holes originates from the drainage of small-volume naturally perched zones. In the final study, the fluids used during drilling of the bottom 100 m of emplacement borehole U-19bh were labeled with a chemical tracer. After hole completion, water level rose in the borehole, while tracer concentration decreased. In fact, total mass of tracer in the borehole remained constant, while water levels rose. After water levels stabilized in this hole, no change in tracer mass was observed over two years, indicating that no movement of water out of the borehole is taking place (as at U- 19ba). Continued labeling tests of standing water are recommended to confirm the conclusions made here, and to establish their validity throughout Pahute Mesa.

Author: University of Nevada System. Water Resources Center
Publisher:
ISBN:
Category : Hydrology
Languages : en
Pages : 128

Get Book Here

Book Description
Price list of available publications.

Author: University and Community College System of Nevada. Water Resources Center
Publisher:
ISBN:
Category : Water resources development
Languages : en
Pages : 128

Get Book Here

Book Description

Author: University of Nevada System. Center for Water Resources Research
Publisher:
ISBN:
Category : Water resources development
Languages : en
Pages : 74

Get Book Here

Book Description

Author:
Publisher:
ISBN:
Category : Hydrology
Languages : en
Pages : 388

Get Book Here

Book Description

Author:
Publisher:
ISBN:
Category : Artesian wells
Languages : en
Pages : 36

Get Book Here

Book Description

Author:
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 34

Get Book Here

Book Description

Author: Richard K. Blankennagel
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 46

Get Book Here

Book Description
Additional title page description: Description of hydraulic testing in deep drill holes and of ground-water characteristics in the Pahute Mesa area.