Nevada Water Science Center


Aquifer Tests

Contact Information

Phil Gardner
Groundwater Specialist
Phone: (775) 887-7664
Email:pgardner@usgs.gov

 

Mailing Address
USGS
Nevada Water Science Center
2730 N. Deer Run Rd.
Carson City, NV 89701

 

Nevada Water Science Center
Information

Home Page Surface Water Groundwater Water Quality Research Contact Us

 

 

Bijou Area, South Lake Tahoe

Primary Investigator: Jena Green

 

Well Data

USGS Site ID
Local Name Altitude Uppermost
Opening
Lowermost
Opening
Primary Aquifer Hydraulic
Conductivity
(ft/d)
385715119562901 MW-194 6306.4 15 25 ALLUVIAL FILL 0.95
385719119565302 MW-196 6242.1 14.4 18.8 ALLUVIAL FILL 0.3
385719119565301 MW-197 6243.7 23.3 27.7 ALLUVIAL FILL 4
385719119565601 MW-198A 6240.6 9.3 13.7 ALLUVIAL FILL 0.75
385720119565602 MW-198B 6240.4 18.8 23.2 ALLUVIAL FILL 6.5
385720119565501 MW-199A 6240.7 10.1 14.5 ALLUVIAL FILL 20
385720119565603 MW-199B 6240.9 19.5 23.9 ALLUVIAL FILL 2.5
385725119565402 MW-201B 6242 12.5 20 ALLUVIAL FILL 8

 

Aquifer Test

All Aquifer Test Files (zip)

Slug Test (pdf) || Related Publication: Scientific Investigations Report 2008-5162

 

Slug tests were conducted in 8 wells in South Lake Tahoe, California to estimate the range of hydraulic conductivities in the alluvium around and upgradient of the Park Avenue detention basins (Figure 1). The slug tests were conducted between June 6, 2006 and June 7, 2006. Results from these slug tests constrained groundwater velocity estimates, which control transport and travel times of nutrients. Hydraulic conductivities of sandy clay to medium sand were estimated.

Site

The slug tests occurred in wells that were completed almost exclusively in sand. Screened intervals ranged from approximately 3 to 24 ft below land surface across thin layers of clay, silt, and fine to medium sands. Seven wells were screened in sandy layers, while the remaining single well located upgradient was screened in sandy clay.

Map of sites

Figure 1. Location of wells for slug tests in South Lake Tahoe, California.

 

Procedures

Water-levels were displaced by about 2 ft (volume of 0.0493 ft3 ) with solid slugs of diameter 0.086 ft. Water levels were measured with a pressure transducer at 1-second intervals to a resolution of 0.01 ft. This sampling frequency defined the waterlevel responses well because the 90-percent recovery time exceeded 10 seconds during all slug tests. The 90-percent recovery time was 12 seconds in well MW 201B and MW 199A which adequately captured the well responses. Between 2 and 4 slug responses were observed in each well.

Analysis

Slug tests were analyzed using analytical solutions coded in spreadsheet software (Halford and Kuniansky, 2002). Slug-test responses were analyzed using Bouwer and Rice (1976). Water-level recovery in well MW 197 was typical (Figure 2) of the 20 responses. Water-level measurements, analyses, and results from all tests are summarized in the file SUMMARY_Bijou.xls.

Hydraulic Property Estimates

Hydraulic conductivity estimates ranged between 0.3 and 20 ft/d (Table 1). The average hydraulic conductivities of medium sand were about 7 ft/d. The average hydraulic conductivity of the sandy clay was 1 ft/d. Overlap existed between the hydraulic conductivities of the sands and the sandy clay as the sands ranged from 0.3 to 20 ft/d while the sandy clay ranged from 0.9 to 1 ft/d.

 

 

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://nevada.usgs.gov/barcass/index.htm
Page Contact Information: Nevada Water Science Center Web Team
Page Last Modified: September 24, 2009 -->