HomeMy WebLinkAbout1.19 Geologic Hazards ReportTPR 176-25
Underground Injection Control Well
Geologic Hazards Report
CPX Piceance Holdings, LLC
34 S. Wynden Drive, Suite 240
Houston, TX 77056
Grand Valley Consulting, LLC dba
(970) 261-3415 jwithers@geotechnicalgroup.net
3510 Ponderosa Way, Grand Junction, Colorado 81506
July 29, 2022
CPX Piceance, LLC
34 S. Wyden Drive, Suite 240
Houston, TX 77056
Attention: Nick Kurtenbach, Principal
713-554-9031
nick@cpxpiceance.com
Subject: Geologic Hazard Report
CPX Well Pad 25A
Beaver Creek, Garfield County, CO
GVC Job No. 4,843
Dear Mr. Kurtenbach,
This letter is to document Geotechnical Engineering Group visited the subject site,
reviewed geologic mapping and reviewed the “Geologic Hazard Assessment, Existing
Tepee Park Ranch Well Pad 25A Site, Garfield County, Colorado” dated February 16, 2022
published by Walter Environmental & Engineering Group Inc. The Walter report identified
no potential geologic hazards impacting the site. The purpose of this report is to address
potential geologic hazards.
SITE CONDITIONS
The subject site was located at latitude 39° 24’ 15” N, longitude -107° 49’ 59” W at an
elevation of approximately 9,160’. It consisted of an existing well pad constructed of an
earth embankment, cut and fill. Embankment construction was made in 2008,
approximately 14 years ago. The existing well pad has a relatively flat and nearly level
surface measuring roughly 350’ x 350’. We used a hand inclinometer to measure the
natural topography above and below the site was 6 to 10 degrees. There was a 50’ cut
slope on the west side of about 1V:1 H slope. We observed the cut slope was revegetated
and has new growth including grass and trees. There was a 30’ fill slope on the east side of
about 1V: 1.7H slope. Review of the “Geologic Map of Colorado” Tweeto, 1979 indicates
alluvial valley fill (including poorly sorted basalt and sedimentary rock detritus) underlain by
Green River Formation. The formation includes siltstone and sandstone.
Grand Valley Consulting, LLC dba
GeoHaz Study CPX 25A, Garfield County, CO
July 29, 2022
GVC Job No. 4,843
Page 2 of 3
GEOLOGIC HAZARDS
House Bill 1041 as passed by the Colorado State Legislature in 1974 was to designate
geologic hazards which, if present, may pose a threat to life or property. In addition, we
understand Garfield County code has additional requirements related to development in
alluvial fan, slopes 20% or more, corrosive or expansive soil and rock, mudflow, and faults.
Observed geologic hazards as outlined by our understanding of House Bill 1041 and
Garfield County code, are discussed below.
1. Radioactivity: Our understanding of site geology, existing and proposed
construction is that radioactive materials and potential for radon gas is not a concern at the
subject site.
2. Seismic Considerations: The subject site is not located within 10 miles of known,
mapped faults. Based on review of mapping we believe seismic activity is not a concern for
the subject site.
3. Ground Subsidence: Ground subsidence is a hazard typically associated with past
mining and collapse of mined areas. We did not observe any mining features on or near the
site. We did not observe fill subsidence or evidence of slope movement at time of our site
visit. We do not believe subsidence potential exists on the site.
4. Landslides: We measured existing slopes of 6° to 10° in vicinity of the site. We
found no mapped or observed landslide in vicinity of the subject site. We do not identify
landslide potential at the subject site.
5. Avalanche: Avalanche hazard is associated with slopes on the order of 30° to 45°.
We identified one area of 45° slope, the 50 foot high cut slope on the east side of the slope.
In our opinion, the cut slope is very limited in nature and does not constitute an avalanche
hazard.
6. Rockfall: We did not observe potential for rockfall or rock roll out. We did not identify
potential rockfall hazard on the subject site.
7. Flood: We found no evidence of flood hazard on or near the subject site.
8. Mudflow and Debris Fans: We found no evidence of mudflow and debris fan hazard
on or near the subject site.
Grand Valley Consulting, LLC dba
GeoHaz Study CPX 25A, Garfield County, CO
July 29, 2022
GVC Job No. 4,843
Page 3 of 3
9. Corrosive / Expansive Soil and Rock: We did not identify obvious evidence of
surface expansive soils/rock exposed at the surface at time of visit. Corrosive / expansive
conditions are not typically associated with the mapped site geology. We do not believe
corrosive or expansive soil conditions impact the subject site.
10. Slopes: We did not observe evidence of slope related movement on or near the
subject site. We found cut and fill slopes that had generally been revegetated and had a
stabile appearance. In our opinion, slope hazard is not a concern for the subject site.
SUMMARY
Results of this study indicate no geologic hazard impacts to the subject site. In our
opinion, there are no geologic hazards identified that preclude the proposed construction.
LIMITATIONS
The scope of work performed is specific to that requested in this report and the
AUTHORIZATION TO PROCEED, ENGINEERING AND TESTING SERVICES between
Grand Valley Consulting, LLC and CPX Piceance , LLC dated July 18, 2022. Other
proposed construction and/or reliance by other clients will require project specific review by
this firm. Changes in site conditions can occur with time. Changes in standard of practice
also occur with time. This report should not be relied upon after a period of three years
from the date of this report and is subject to review by this firm in light of new information
which may periodically become known. We believe this investigation was conducted in a
manner consistent with that level of care and skill ordinarily used by engineers practicing in
this area at this time. If we can be of further service in discussing the contents of this report
or the analysis of the influence of the subsurface conditions on the construction, please
call.
Sincerely,
Grand Valley Consulting, dba
GEOTECHNICAL ENGINEERING GROUP
John Withers, P.E.
Engineer
(1 copy emailed)
8/7/20158-11-2022