Fish

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Title
UTAH GEOLOGICAL SURVEY WEST DESERT GROUND- WATER
MONITORING PROJECT Informal Technical
Session December 09, 2008
Hugh Hurlow, Lucy Jordan, Matt Affolter, Mike
Lowe Utah Geological Survey
Twin Springs
Fish Springs
Great Basin Carbonate Aquifer
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Program summary

• Summary of Monitor-Well Drilling Program
• 3.5M over 2 years (July 1, 2007
• to June 30, 2009)
• Wells in basin-fill and carbonate
• aquifers
• Located near proposed SNWA well field areas of
  suspected
• interbasin regional flow agricultural areas
  environmentally
• sensitive springs wetlands saline water
  monitoring
• Characterize background water levels and
  chemistry
• understand regional flow in carbonate
  basin-fill aquifer
• systems their connectivity quantify future
  drawdown
• data for future ground-water flow models

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Update
UTAH GEOLOGIAL SURVEY WEST DESERT GROUND-WATER
MONITORING PROJECT PROGRESS UPDATE

• Three-fourths complete in work and budget as of
• December 31, 2008
• 26 sites 47 boreholes 64 wells (piezometers)

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Project map 1
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Water levels
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Water levels 2
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chemistry1
Previous Data
UGS Monitor Wells
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Data table
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Results
Results          Water quality is typically
good (lt500 ppm total-dissolved-solids
concentrations) in the upper 1000 feet of
both the basin-fill and bedrock aquifers. TDS
increases markedly below 1000
feet.          Water levels vary from 22 to
1426 feet below land surface. Water levels are
shallowest in the Snake Valley basin center, and
deepest in the Confusion Range east of Snake
Valley. In our new monitor wells on the eastern
and western margins of Snake Valley, water
levels are similar in the basin-fill and bedrock
aquifers, suggesting close connection of the
two aquifers. These wells show a slight downward
vertical gradient, suggesting recharge to the
carbonate aquifer. Upward vertical gradients are
observed in the Snake Valley basin center,
indicating discharge from the basin-fill
aquifer toward the land surface.         
Preliminary data suggest that most ground water
in Snake Valley is a mixture of modern
(recharged lt50 years ago) and old (recharged
2,000 to 22,000 years ago) waters.         
Our preliminary aquifer test of the carbonate
aquifer yielded a fairly high transmissivity,
consistent with results from SNWAs test of the
same aquifer in Spring Valley.
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Future work
UTAH GEOLOGIAL SURVEY WEST DESERT GROUND-WATER
MONITORING PROJECT PROGRESS UPDATE

• Work for 2009
• Aquifer tests (2 Site 11 The Cove Site 3 East
  of Garrison)
• Boreholes (1 to 5 Sand Pass, Gandy Salt Marsh
  South, Upper
• Swazey Wash, other???)
• Spring-Discharge Gauges (Miller Ranch, Foote
  Reservoir, Twin
• Springs, ?Coyote Spring, ?Dearden Ranch
• Saline-water monitoring wells
• Re-sample selected wells

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Results benefits
Uses and Implications          This
ground-water monitoring system will provide an
early warning of future ground-water level
changes in Snake Valley.          Long-term,
continuous water-level monitoring will help
define trends under current conditions,
better quantify available resources, and quantify
changes if/when new pumping occurs.         
Aquifer-test data will help quantify the capacity
of the bedrock (carbonate) aquifer to
transmit and store ground water.         
Spatial distribution of sites will help
understand regional-scale flow patterns
including interbasin flow.          We expect
that our results will be will be incorporated
into SNWAs ground-water flow model for their
pipeline EIS, and the model they will present to
the Nevada State Engineer at the Snake Valley
hearing in Fall of 2009.
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dissemination
UTAH GEOLOGIAL SURVEY WEST DESERT GROUND-WATER
MONITORING PROJECT PROGRESS UPDATE

• Dissemination
• Project Description and Results available on
• UGS web page
• http//www.ugs.state.ut.us/esp/snake_valley_projec
  t/index.htm
• (updated quarterly)
• Summary report at end of project
• Uses of Data
• Detect water-level changes early to allow
  mitigation
• Calibration of new ground-water flow model
• for US BLM EIS for SNWA pipeline
• ?? Monitoring system as part of interstate and/or
• stipulated agreement (neither currently in
  place)

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Project Map 2
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All applications
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Site types
Basin-fill Aquifer
Carbonate Aquifer
Site Types
Springs Wetlands
Agricultural areas
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completion1
Basin Fill Single-Completion Well Diagram not to
scale
Carbonate Single-Completion Well Diagram not to
scale
12 ¼ borehole diameter
10 ft
14 ¾ borehole diameter
10 ft
20 ft
Concrete
6.5 borehole diameter
10 ft
6 5/8 OD 250 wall steel casing 20 into bedrock
20 ft
2 sch 80 PVC
bentonite grout
¼ time-release bentonite pellets, 10 ft
6 1/8 borehole diameter
Paired Carbonate-Basin Fill Monitor Well Design
sand filter pack
20 2 sch 80 0.02-slot PVC screen
Well design by Lucy Jordan (UGS) Steve Crawford
(USGS)
Paired well diagram
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completion2
Dual-Completion Well Diagram - not to
scale -
Double-wall steel locking hole enclosure (minimum
2.5 bgl)
Well stick-up min 1.5 agl w/ venting cap
10 ¾ OD 250 wall steel casing to 20 ft
Concrete
12 ¾ borehole diameter
8 ¾ borehole diameter
¼ time-release bentonite pellets
20-40 2 sch 80 .02 slot PVC screen
2x12 mesh (3 Monterey) sand pack 20 abv 10
blw screen
¼ time-release bentonite pellets
30-solids bentonite grout
2 sch 80 PVC pipe
¼ time-release bentonite pellets
20 2 sch 80 .02 slot PVC screen
2x12 mesh (3 Monterey) sand pack 20 abv 10
blw screen
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completion3
Spring-Gradient Well Diagram - not to
scale -
completion2
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Regional map
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ag1
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ag2
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Sensitive Species

• On UT Division of Wildlife Resources
• Sensitive Species List, Tier 1 (highest
  priority)
• Occupy spring pools riparian habitat in
• Snake Valley, Tule Valley, Fish Springs
• Potential candidates for Federal listing as
• threatened species

Indigenous To Utah
Info.from Chris Keleher, DNR Endangered
Species Program
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Conceptual flow
From USGS SIR 2007-5261 (BARCAS final report)
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Hydrologic Budgets
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hydrostratigraphy
Basin-fill aquifer
upper
lower
Hydrostratigraphy
Upper Paleozoic carbonate aquifer
Middle confining unit
Lower Paleozoic carbonate aquifer
Modified from Hintze and others (2000)
Lower confining unit
hydrostratigraphy
Hydrostratigraphy
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Basin fill 2
Data from Saltus and Jachens, 1995
Basin-FillAquifer
Basin Fill