SAN JOAQUIN EXPERIMENTAL RANGE
RESEARCH REQUEST FORM
Project Director/Principal Investigator: Roger Bales
Affiliation and contract information: University of California, Merced
Southern Sierra Critical Zone Observatory. RBales@ucmerced.edu
Field Manager contact: mmeadows@ucmerced.edu
Collaborators: Cliff Riebe, Anthony O’Geen, Peter Hartsough, Matthew Meadows
Project Title: Geoprobe and Geophysics of the Critical Zone
Attach an extended project proposal that includes background, justification,
objectives, methods, and time line.
We would like to do additional monitoring into the deeper saprolite and bedrock
at the San Joaquin Experimental Range (SJER) site (see attached map and GPS
locations). This project has two components: Geoprobe and Geophysics. A major thrust
of our proposed work is to quantify weathering, fracture spacing and orientation, water
content, and the size and distribution of macropores and subsurface corestones. By
coupling direct measurements of subsurface properties from the Geoprobe together with
indirect measurements from geophysics we will address the fundamental, methodological
problem of calibrating geophysical surveys, which are relatively easy to apply over broad
scales and minimally invasive. Hence it is important that the Geoprobe measurements are
co-located with the geophysical surveys insomuch as possible.
Geoprobe:
The purpose of this component is to collect a small number of physical samples
for analysis, while also allowing for the installation of water monitoring wells in the
subsurface. Our proposal is to use a Geoprobe (http://geoprobe.com/) sonic drilling rig to
collect samples down to ~10m and install monitoring wells at these sites. We chose the
Geoprobe, largely because it was inexpensive (we have one available at UC Davis) and is
very low impact. We propose to do dry drilling so would not be introducing any water or
other drilling fluids. The Geoprobe runs on a track, which minimizes disturbance to offroad areas. We would like to attempt 7-11 drilling locations, which may go as deep as
12m, along the geophysical transect going from the ridge south to and across the main
access road. Wells will be completed with 2" PVC, slotted in the bottom ~2m for
monitoring subsurface water. We do not expect to encounter any groundwater while
drilling in late summer/early fall. However, we do expect instrumentation in the wells to
reveal transient groundwater during the winter. We plan to collect continuous soil and
rock cores from all the wells which will be analyzed for physical and chemical properties
of the saprolite and deep water therein. Location is flexible but will generally be with the
vicinity of the existing flux tower at SJER (37.109N, 119.731W) but in an area not in
conflict with the existing NEON instrumentation. Please see attachments for general
location, although final well locations may be slightly different.
Geophysics:
The purpose of this component is to obtain a better understanding of the geology
and regolith formation at SJER using non-invasive geophysical techniques. Our
geophysical surveys will include seismic refraction, resistivity, ground-penetrating radar,
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nuclear magnetic resonance, gravity and magnetics along transects near our current SJER
Flux Tower site.
None of the geophysical techniques will result in significant or lasting disturbance
to the landscape. The gravity and magnetic surveys are completely passive and can be
conducted with instruments carried over the ground by a team of two researchers.
Seismic refraction and resistivity surveys are more labor intensive, requiring a team of
four or five researchers, because of the amount of equipment involved. However both
techniques are minimally invasive and can be conducted at the same time to minimize
disturbance. In seismic refraction surveys, a connected line of 96 geophones is distributed
across the surface at regular intervals. Geophones need to be in solid contact with the
ground, and have a two-inch spike on one end so that they can be driven into the soil. On
removal, after our survey, we will backfill the small holes thus produced. Seismic
refraction surveys measure the velocity and attenuation of seismic energy in the
subsurface. Hence seismic energy must be applied to the subsurface. This is done with a
sledge hammer applied with vigor to a steel plate. To obtain a distributed view of the
subsurface over the entire transect, we will need apply energy to multiple “shot points”
along the transect. At each shot point a series of 5-10 blows is needed to optimize the
signal-to-noise ratio in the seismic data. In resistivity surveys, an array of connected
electrodes (similar to the geophones) is distributed and driven into the top 2-3 inches of
soil for the resistivity surveys. The resistivity surveys measure resistance of the
subsurface to passing a current. Hence a current must be applied to the subsurface to
obtain measurements; this is accomplished with pulses of current routed through the
electrodes from a car battery. The applied current is minimally invasive and should have
no effect on biota.
Describe the project location, including SJER range unit numbers.
Project location will be within footprint of existing Flux Tower (37° 6'31.3992"N,
119° 43'53.6196) and approximately in a transect running south of the tower, across the
road and up the adjacent hill (see attached map). Non-invasive geophysics lines may also
run perpendicular to this transect.
Describe the duration of use and activity periods.
Project duration should be 1-2 weeks of on-site activity for each portion of the
project (Geoprobe and Geophysics). Project timeframe is August to December, 2013 and
continuing Spring to early Winter 2014. All Geoprobe activity will occur within a short
2-7 day period, likely in 2013 including a team of 4-6 people. Geophysics activity would
likely occur in 2014 including a team of 5-10 people. Access to monitor installed wells
would continue into the future and have a limited number of people (1-2 people for 1 day
per visit).
Describe any markers, including tags, flagging, stakes, or other to be used. Will
GPS location data be collected at these locations?
No permanent markers or stakes are needed. We request to install PVC well
casing into the geoprobe holes and potentially instrument them with water monitoring
equipment. Well casing can be flush with surface or may protrude less than 5 inches
above surface.
Will the use or exclusion of CSUF livestock be needed as part of the experiment?
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For livestock use, describe the location, timing, duration, and movements desired.
For exclusion, describe the location and duration. Identify whether any new fencing
is needed. Concurrence from CSUF is required.
No
Randy Perry
California State University, Fresno
Will other SJER or CSUF facilities be needed? If so, which facilities and for what
purpose?
Housing during field operation may be requested by individual researchers.
Do you intend to publish your results?
Yes. We plan on publishing and will acknowledge the contributions of CSUF
and/or PSW in published materials. Current and future publications can be accessed
through our website: http://criticalzone.org/sierra
Will project include use of toxic chemicals?
No
Please provide the required proof of liability insurance.
See attached self-insurance document.
________________________________________________________________________
I will provide annual progress statements and two copies of all published reports plus a
final report at the end of the study. In addition, I agree to remove all study markers at the
end of the study at my project expense.
_______________________________
Project Director/Principle Investigator
______________________
Date
SUBMIT THIS FORM TO DR. KATHRYN PURCELL (kpurcell@fs.fed.us)
Distribution: The SJER Committee (Kathryn Purcell, Randy Perry, Ken Tate, Mel George, Kevin Rice),
Renee Denton, Neil McDougald, Mike Mosinski, and Anthony Suniga.
Rev 13 Nov 2012
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