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Data from a thick unsaturated zone in Joshua Tree, San Bernardino County, California, 2007--09

Data Series 717

Prepared in cooperation with the Joshua Basin Water District
By:
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Abstract

Data were collected on the physical properties of unsaturated alluvial deposits, the chemical composition of leachate extracted from unsaturated alluvial deposits, the chemical and isotopic composition of groundwater and unsaturated-zone water, and the chemical composition of unsaturated-zone gas at four monitoring sites in the southwestern part of the Mojave Desert in the town of Joshua Tree, San Bernardino County, California. The presence of denitrifying and nitrate-reducing bacteria from unsaturated alluvial deposits was evaluated for two of these monitoring sites that underlie unsewered residential development. Four unsaturated-zone monitoring sites were installed in the Joshua Tree area—two in an unsewered residential development and two adjacent to a proposed artificial-recharge site in an undeveloped area. The two boreholes in residential development areas were installed by using the ODEX air-hammer method. One borehole was drilled through the unsaturated zone to a depth of 541 ft (feet) below land surface; a well screened across the water table was installed. Groundwater was sampled from this well. The second borehole was drilled to a depth of 81 ft below land surface. Drilling procedures, lithologic and geophysical data, construction details, and instrumentation placed in these boreholes are described. Core material was analyzed for water content, bulk density, matric potential, particle size, and water retention. The leachate from over 500 subsamples of cores and cuttings was analyzed for soluble anions, including fluoride, sulfate, bromide, chloride, nitrate, nitrite, and orthophosphate. Groundwater was analyzed for major ions, inorganic compounds, select trace elements, and isotopic composition. Unsaturated-zone water from suction-cup lysimeters was analyzed for major ions, inorganic compounds, select trace elements, and isotopic composition. Unsaturated-zone gas samples were analyzed for argon, oxygen, nitrogen, methane, carbon dioxide, ethane, nitrous oxide, and carbon monoxide. Drill cuttings were analyzed for denitrifying and nitrate-reducing bacteria. One of the boreholes installed adjacent to the Joshua Basin Water District proposed groundwater-recharge facility was installed by using the ODEX air-hammer method and the other was installed by using a 7.875-inch hollow-stem auger. Drilling procedures, lithologic and geophysical data, construction details, and instrumentation placed in these boreholes are described; however, geochemical data were not available at the time of publication.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Data from a thick unsaturated zone in Joshua Tree, San Bernardino County, California, 2007--09
Series title:
Data Series
Series number:
717
Year Published:
2012
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
California Water Science Center
Description:
vii, 103 p.
Number of Pages:
114
Time Range Start:
2007-01-01
Time Range End:
2009-12-31
Country:
United States
State:
California
County:
San Bernardino County
City:
Joshua Tree
Additional Online Files(Y/N):
N