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NATURAL AND GEOLOGIC HAZARDS
ASSESSMENT REPORT
URSA OPERATING COMPANY
BATTLEMENT MESA PUD PHASE 11
GARFIELD COUNTY, COLORADO
PREPARED FOR
URSA OPERATING COMPANY
1050 17TH STREET, SUITE 2400
RIFLE, COLORADO 81650
PREPARED BY
OLSSON ASSOCIATES
4690 TABLE MOUNTAIN DRIVE, SUITE 200
GOLDEN, COLORADO 80403
JULY 2017
PROJECT No. 016-3531
O‘OLSSON
ASSOCIATES
Natural and Geologic Hazard Report Preface
Garfield County, Colorado, finalized the Land Use and Development Code (LUDC) with an
effective date of July 15, 2013, last amended December 12, 2016. The Garfield Board of County
Commissioners (BOCC) adopted the LUDC to fully exercise all relevant powers conferred by
the laws of the State of Colorado as provided under the Colorado Constitution and State
Enabling Legislation.
ARTICLE 7: Standards, Section 7-108. USE OF LAND SUBJECT TO NATURAL HAZARDS,
states that land subject to identified Natural and Geologic Hazards, such as falling rock,
landslides, snow slides, mud flows, radiation, flooding, or high water tables, shall not be
developed unless it has been designed to eliminate or mitigate the potential effects of
hazardous site conditions as designed by a qualified professional engineer and as approved by
the County. Section 7-207. NATURAL AND GEOLOGIC HAZARDS requires a Natural and
Geologic Hazard Study be prepared by a qualified professional geologist be submitted with a
development plan or plat.
According to the Garfield County LUDC Section 4-203. Description of Submittal Requirements,
page 4-24, the professional qualifications for preparation and certification of certain documents
required by this Code are as follows:
"Geologist. Geology reports shall be prepared by either a member of the American
Institute of Professional Geologists, a member of the Association of Engineering
Geologists, or a qualified geotechnical engineer licensed in the State of Colorado."
A search of the Colorado Department of Regulatory Agencies (DORA) Licensed Professions
and Businesses indicates that Colorado licenses "professional engineers" and "engineer interns"
but does not appear to have a license specific to "geotechnical engineers." According to the
Colorado Geologic Survey, currently, the State of Colorado does not require licensure or
registration of geologists. Colorado Revised Statutes do require that geologic reports be
prepared or authorized by a professional geologist, and "Professional Geologist" is a term
defined in Colorado Statutes.
The references for these Statutes are shown here:
23-41-208. Definitions. As used in this part 2, unless the context otherwise requires:
• "Geology" means the science which treats of the earth in general; the earth's processes
and its history; investigation of the earth's crust and the rocks and other materials which
compose it; and the applied science of utilizing knowledge of the earth's history,
processes, constituent rocks, minerals, liquids, gases, and other materials for the use of
mankind.
• "Professional Geologist" is a person engaged in the practice of geology who is a
graduate of an institution of higher education which is accredited by a regional or
national accrediting agency, with a minimum of thirty semester hours (forty-five quarter)
hours of undergraduate or graduate work in a field of geology and whose post
baccalaureate training has been in the field of geology with a specific record of an
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additional five years of geological experience to include no more than two years of
graduate work.
• (2). Reports containing geologic information. Any report required by law or by rule and
prepared as a result of or based on a geologic study or on geologic data, or which
contains information relating to geology and which is to be presented to or is prepared
for any state agency, political subdivision of the state, or recognized state or local board
or commission, shall be prepared or approved by a Professional Geologist.
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Professional Geologist Certification
By means of this certification, I attest that:
• I am qualified to prepare a Natural and Geologic Hazard Study in accordance with
the provisions of Section 7-207 of the Garfield County LUDC, and that I am a
member of the American Institute of Professional Geologists per LUDC 4-203.
▪ Although I have not visited the proposed sites, I am familiar with the geology and
have performed field work in the area of the proposed Ursa Operating Company LLC
Battlement Mesa PUD Phase II natural gas well pads, water storage pad, and
pipeline sites located in Township 7 South, Range 95 West and Township 7 South,
Range 96 West, 6th Principal Meridian in Garfield County, Colorado.
• Although the Colorado Geological Survey does not currently have a licensing or
registration program for professional geologists practicing in the state of Colorado,
there are requirements within local and state statutes that require that geologic
reports be prepared by a professional geologist. I attest that I meet the requirements
of the Colorado Geological Survey's definition of a professional geologist having
completed and met the educational requirements of the Colorado Geological Survey
definition.
• I am a licensed Professional Geologist and Professional Geoscientist in other States,
including Texas, Utah and Wyoming which do have licensing programs for
professional geologists. I am a current member of the American Institute of
Professional Geologists (AIPG).
▪ I have reviewed published geologic maps and reports applicable to this area and
have considered the implications of these conditions in the context of the proposed
development and the Garfield County LUDC.
• This report has been prepared in accordance with good scientific principles and
engineering practices including consideration of applicable industry standards, and
with consideration of the requirements of the National Association of State Boards of
Geology. The conclusions and recommendations contained in this report are based
on information available and known to me at the time of this report. Good scientific
principles and standard engineering practices were taken into consid _�;,,, o in
arriving at the conclusions and recommendations made in this r
Prepared by:
darrnes W. Hix, PG
Senior Geologist
Date: 04/19/2017
Note: The PG's certification does not relieve the ownedoperator of the facility of the duty to review this report or fully implementing
the recommendations in accordance with all applicable federal, state, and local requirements in order to achieve the desired goals
or objectives.
Geologic and Natural Hazard Report
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Olsson Associates
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TABLE OF CONTENTS
Natural and Geologic Hazard Report Preface
Professional Geologist Certification
TABLE OF CONTENTS iv
APPENDIX A FIGURES iv
APPENDIX B ADDENDUM v
1.0 EXECUTIVE SUMMARY 1
1.1 Proposed Sites 1
1.2 Evaluation Summary of Potential Geologic Hazards 2
2.0 GENERAL SITE LOCATION AND REGULATORY BACKGROUND 3
2.1 Garfield LUDC Natural and Geologic Hazard Assessment 3
2.2 Garfield County Natural Hazard Mitigation Plan 8
2.3 Battlement Mesa Community PUD Phase II Project and Site Description 8
2.4 Structural Geology 8
2.5 Geology 8
2.6 Soil 9
2.7 Hydrologic Setting 10
2.8 Aquifers 11
3.0 NATURAL AND GEOLOGIC HAZARD ASSESSMENT 12
3.1 Utilities 12
3.2 Avalanche Hazard Area 12
3.3 Landslide Areas or Potential Landslide Hazard Areas 13
3.4 Rockfall Areas 13
3.5 Alluvial Fan Hazard Areas 13
3.6 Unstable or Potentially Unstable Slopes 13
3.7 Corrosive or Expansive Soils and Rock 15
3.8 Mudflow and Debris Fan Areas 15
3.9 Development Over Faults and Risk of Seismic Activity 16
3.10 Flood Prone Areas 17
3.11 Collapsible Soils 17
3.12 Mining Activity 18
3.13 Radioactivity 18
4.0 Conclusions and Recommendations 19
5.0 References 21
APPENDIX A FIGURES
List of Figures
Battlement Mesa PUD Phase II
• Vicinity Map — Battlement Mesa PUD Phase II Overview
• Surface Water and Water Wells Map — Battlemetn Mesa PUD Phase II
• Flood Plain Map — Battlement Mesa PUD Phase II
• Vicinity Map — Battlement Mesa PUD Phase II Pipelines
Battlement Mesa PUD - BMC A Pad
• Vicinity Map
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• Surface Geology Map
• Soils Map
• Surface Water and Water Wells Map
• BMC A Pipeline Adjacent Landowners and Structures
• BMC A Pipeline Property Owners
Battlement Mesa PUD BMC F Pad
• Vicinity Map
• Surface Geology Map
• Soils Map
• Surface Water and Water Wells Map
• BMC F Pipeline Adjacent Land Owners and Structures
• BMC F Pipeline Property Owners
Battlement Mesa PUD BMC L Pad
• Vicinity Map
• Surface Geology
• Soils
• Surface Water and Water Wells Map
• BMC L Pipeline Adjacent Land Owners and Structures
• BMC L Pipeline Property Owners
APPENDIX B ADDENDUM
• Seismic Hazards Associated with the Ursa Operating Company, LLC BMC A Pad Class
II Underground Injection Control Activity
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1.0 EXECUTIVE SUMMARY
Olsson Associates (Olsson) was contracted by Ursa Operating Company (Ursa) to assess
natural and geologic hazards potentially present in the area of the proposed Battlement Mesa
(BM) planned unit development (PUD) Phase II for the construction of natural gas production
well pads, water storage, flow and gathering pipelines (Sites) to be located in parts of Sections
8, 16, 17, and 18, Township 7 South, Range 95 West, and part of Section 13, Township 7
South, Range 96 West, of the 6t" Principal Meridian, Garfield County, Colorado. The Sites are at
an elevation of about 5,200 feet to 5,800 feet above mean sea level (amsl) as shown on the
attached Battlement Mesa PUD Phase II Vicinity Map.
The purpose of this report is to identify geologic conditions that may pose hazards to a land
development project in order that appropriate mitigation or avoidance techniques may be
implemented as described in the Garfield County Land Use Development Code (LUDC),
effective July 15, 2013, last amended December 12, 2016. According to the Garfield County
LUDC, Section 7-207, the types of natural and geologic hazards identified pertain to the
following:
A. Utilities;
B. Development in Avalanche Hazard Areas;
C. Development in Landslide Hazard Areas;
D. Development in Rockfall Hazard Areas;
E. Development in Alluvial Fan Hazard Areas;
F. Slope Development;
G. Development on Corrosive or Expansive Soils and Rock;
H. Development in Mudflow Areas;
I. Development Over Faults and Seismicity;
J. Radioactive Areas; and
K. Potentially Unstable Soils.
This report presents Olsson findings following an evaluation of these and other geologic
hazards potentially affecting the Sites and proposed development. The Ursa Operating
Company Sites were found to be suitable for the proposed development with consideration of
the following identified geologic hazards.
1.1 Proposed Sites
The following Sites are proposed to be completed as part of the Ursa BM PUD Phase II
development:
• BMC A Well Pad: SE % SE '/4 Section 13, T7S, R96W - 24 wells
• BMC L Well Pad: SE 1/4 NW % Section 8, T7S, R95W - 33 wells
• BMC F Water Storage: SW 1/4 SW '/4 Section 16, T7S, R95W — water storage tanks
• Phase II Pipelines: SW '/4 NE '/4 Section 8 and NW '/4 SW % Section 18, T7S, R95W.
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The proposed BM PUD Phase II Pads are shown on the Vicinity Maps. The BMC A Pad is
located south of the Battlement Mesa waste water treatment facility with an access road off
River Bluff Road (County Road 307) to the northeast. There are housing developments located
to the south and east of the BMC A Pad Site. The BMC F Pad is located to the southwest of the
intersection of Four Corners Road and Underwood Lane (County Road 302). The BMC L Pad is
located to the west side of Spencer Parkway, south of the intersection with North Battlement
Parkway (County Road 300N).
1.2 Evaluation Summary of Potential Geologic Hazards
The following table presents a summary of the evaluation of geologic hazards potentially
affecting each of the proposed Ursa BM Phase 11 development Sites. This report should be read
in its entirety to gain a full understanding of the evaluation process and the rationale behind the
assignment of the hazards listed below for each Site.
SITE NAME
BMC A
Well Pad
BMC L
Well Pad
BMC F
Well Pad
Phase II
Pipelines
Potential Geologic Hazard
A. Utilities
N/A
N/A
N/A
N/A
B. Avalanche Area
N/A
N/A
N/A
N/A
C. Landslide Area
N/A
N/A
N/A
N/A
D. Rockfall Area
N/A
N/A
N/A
N/A
E. Alluvial Fan Area
N/A
N/A
N/A
N/A
F. Slope Area
X
X
X
X
G. Corrosive Soils
X
X
X
X
H. Expansive Soils
X
N/A
N/A
N/A
I. Mudflow Area
N/A
N/A
N/A
N/A
J. Faults/Seismicity
N/A
N/A
N/A
N/A
K. Radioactive Areas
N/A
N/A
N/A
N/A
L. Unstable Soils
N/A
N/A
N/A
N/A
X — Potential for geologic hazard to affect proposed development
N/A — Not Applicable
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2.0 GENERAL SITE LOCATION AND REGULATORY BACKGROUND
Ursa Operating Company LLC (Ursa) contracted Olsson Associates (Olsson) to conduct a
natural and geologic hazards assessment as defined in the Garfield County LUDC for the
proposed development of the BM PUD Phase II pads and associated gathering pipelines. The
proposed facilities will be used for exploration and production of natural gas, water storage, and
pipelines. The following sections present the LUDC definitions of natural and geologic hazards
as well as an overview of the BM PUD Phase II Development setting.
2.1 Garfield LUDC Natural and Geologic Hazard Assessment
According to the LUDC ARTICLE 7: STANDARDS, Section 7-108 Use of Land Subject to
Natural Hazards:
"Land subject to identified Natural and Geologic Hazards, such as falling rock, landslides, snow
slides, mud flows, radiation, flooding, or high water tables, shall not be developed unless it has
been designed to eliminate or mitigate the potential effects of hazardous site conditions as
designed by a qualified professional engineer and as approved by the County."
The LUDC defines a geologic hazard as "A geologic phenomenon that is so adverse to past,
current, or foreseeable construction or land use as to constitute a significant hazard to public
health and safety or to property."(LUDC Section 15-102. Definition of Words and Phrases, page
15-14).
The LUDC defines a Hazard Area as "An area that contains oris directly affected by a geologic
hazard, including but not limited to the following types of areas."(LUDC Section 15-102.
Definition of Words and Phrases, page 15-14).
A. Utilities. "Above -ground utility facilities located in Hazard Areas shall be protected
by barriers or diversion techniques approved by a qualified professional
engineer. The determination to locate utility facilities above ground shall be
based upon the recommendation and requirements of the utility service provider
and approved by the County.
B. Development in Avalanche Hazard Areas or Avalanche Area. An avalanche is
defined as "A mass of snow or ice and other material that may become
incorporated therein as such mass moves rapidly down a Slope." (LUDC Section
15-102. Definition of Words and Phrases). Development may be permitted to
occur in Avalanche Hazard Areas if the development complies with the following
minimum requirements and standards, as certified by a qualified professional
engineer, or qualified professional geologist, and the plan is approved by the
County.
1. Building construction shall be certified to withstand avalanche impact and
static loads and otherwise protected by external avalanche defense structures
that have been similarly certified.
2. Driveways and Subdivision roads shall avoid areas where avalanches have
return periods of fewer than 10 years.
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3. Clear -cutting or other large-scale removal of vegetation is prohibited in
avalanche path starting zones, or other locations that can increase the potential
avalanche hazard on the property.
4. Extractive operations in Avalanche Hazard Areas are prohibited when snow is
on the ground unless a program of avalanche control and defense measures has
been approved by the County to protect the operation.
C. Development in Landslide Hazard Areas.
A Landslide Hazard Area is defined as "An area with demonstrably active mass
movement of rock and soil where there is a distinct surface rupture or zone of
weakness that separates the landslide material from more stable underlying
material." (LUDC Section 15-102. Definition of Words and Phrases).
Development may be permitted to occur in Landslide Hazard Areas only if the
development complies with the following minimum requirements and standards,
as certified by a professional engineer, or qualified professional geologist, and as
approved by the County.
1. Development shall comply with recommended construction practices to
artificially stabilize, support, buttress, or retain the potential slide area and to
control surface and subsurface drainage that affects the slide area.
2. The following development activities shall be prohibited in Landslide Hazard
Areas:
a. Activities that add water or weight to the top of the slope, or along the
length of the slope, or otherwise decrease the stability of the Hazard Area.
Measures and structural improvements to permanently control surface and
subsurface drainage from the development shall be required.
b. Activities that remove vegetation or other natural support material that
contribute to its stability.
c. Activities that increase the steepness of a potentially unstable slope.
d. Activities that remove the toe of the landslide, unless adequate mechanical
support is provided.
D. Development in Rockfall Hazard Areas.
According to the Colorado Geological Survey (CGS), falling rocks are a special
category of the large family of gravitationally driven phenomena called landslides.
What are commonly called rockfall events generally fall into four technical
definitions: rockfall, rock topple, rock avalanche, and rock slide. Rockfall events
may involve one or more of these technical definitions and may grade into one
another. Development shall be permitted to occur in Rockfall Hazard Areas only
if the applicant demonstrates that the development cannot avoid such areas and
the development complies with the following minimum requirements and
standards, as certified by a qualified professional engineer, or a qualified
professional geologist, and as approved by the County.
1. Development shall comply with recommended construction practices to
minimize the degree of hazard. Construction practices may include:
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a. Stabilizing rocks by bolting, gunite application (cementing), removal of
unstable rocks (scaling), cribbing, or installation of retaining walls.
b. Slowing or diverting moving rocks with rock fences, screening,
channeling, damming, or constructing concrete barriers or covered
galleries.
c. Installation of structural barriers around vulnerable structures to prevent
rock impact.
2. The following development activities shall be prohibited in Rockfall Hazard
Areas:
a. Activities that add water or weight to, or otherwise decrease the stability
of, cliffs or overhanging strata.
b. Activities that will reduce stability, including activities that remove
vegetation or other natural support material, or that require excavation, or
cause erosion that will remove underlying support to a Rockfall Hazard
Area.
E. Development in Alluvial Fan Hazard Area.
According to the CGS, alluvial fans are defined as fan -shaped or cone-shaped
deposits of water -transported sediment, alluvium, that typically form at the base
of topographic features such as mountains or mesas, especially in areas with
steep slopes.
Development shall only be permitted to occur in an alluvial fan if the applicant
demonstrates that the development cannot avoid such areas, and the
development complies with the following minimum requirements and standards,
as certified by a qualified professional engineer, or qualified professional
geologist, and as approved by the County:
1. Development shall be protected using structures or other measures on the
uphill side that channel, dam, or divert the potential mud or debris flow.
2. Disturbance shall be prohibited in the drainage basin above an alluvial fan,
unless an evaluation of the effect on runoff and stability of the fan and on the
groundwater recharge area shows that disturbance is not substantial or can
be successfully mitigated.
F. Slope Development.
Development on slopes of twenty percent (20%) or greater shall only be
permitted to occur if the applicant demonstrates that the development complies
with the following minimum requirements or standards, as certified by a qualified
professional engineer, or qualified professional geologist, and as approved by the
County:
1. Building lots with 20% or greater slope shall require a special engineering
study to establish the feasibility of development proposed for the site. The
study shall address feasibility of construction required for the use and
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describe the mitigation measures to be used to overcome excessive slope
problems.
2. Development shall be permitted to occur on slopes greater than 30% only if
the applicant demonstrates that the development cannot avoid such areas
and the development complies with the following minimum requirements:
a. Cutting, filling, and other grading activities shall be confined to the
minimum area necessary for construction.
b. Development shall be located and designed to follow natural grade,
rather than adjusting the site to fit the structure. Roads and driveways
built to serve the development shall follow the contours of the natural
terrain and, if feasible, shall be located behind existing landforms.
3. Development on Unstable or Potentially Unstable Slopes. If a site is identified
as having moderate or extremely unstable slopes, then development shall be
permitted only if the applicant demonstrates that the development cannot
avoid such areas and the development complies with certified geotechnical
design and construction stabilization and maintenance measures.
a. Cutting into the slope is prohibited without provision of adequate
mechanical support.
b. Adding water or weight to the top of the slope, or along the length of
the slope, is prohibited.
c. Vegetation shall not be removed from the slope unless the integrity of
the slope can be adequately maintained.
4. Development on Talus Slopes. Development shall be permitted to occur on a
talus slope only if the applicant demonstrates that the development cannot
avoid such areas, and the development complies with the following minimum
requirements and standards, as certified by a qualified professional engineer,
or a qualified professional geologist, and as approved by the County.
a. The development shall be designed to withstand down slope
movement.
b. The design shall include buried foundations and utilities below the
talus slope surface.
c. Site disturbance shall be minimized to avoid inducing slope instability.
d. The toe of a talus slope shall not be removed unless adequate
mechanical support is provided.
G. Development on Corrosive or Expansive Soils and Rock
Development in areas with corrosive or expansive soils and rock shall be
designed based upon an evaluation of the development's effect on slope stability
and shrink -swell characteristics. Development shall be permitted only if the
applicant demonstrates that the development cannot avoid such areas and the
development complies with design, construction stabilization, and maintenance
measures certified by a qualified professional engineer, or qualified professional
geologist, and is approved by the County.
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1. Surface drainage shall be directed away from foundations.
2. Runoff from impervious surfaces shall be directed into natural drainages or
otherwise on-site in a manner that does not create or increase adverse
impacts to the development site or to adjacent or other property.
H. Development in Mudflow Areas.
Debris flows, fans, and mudslides are a common hazard in steep hillside areas of
Colorado. A mudflow debris area is defined as "An area subject to rapid mud and
debris movement or deposit occurring after mobilization by heavy rainfall or
snowmelt runoff. Such areas are formed by successive episodes of deposition of
mud and debris." (LUDC Section 15-102 Definition of Words and Phrases). On
flatter ground near the bottom of the hill side, they form "alluvial fans," similar to
those described above in Item E. Development in Alluvial Fan Hazard Areas, but
built up by debris flows rather than streams. They can mobilize anything in their
path and may consist of more solid material than liquid. The resulting fans are
more accurately described as debris cones or colluvial fans.
Development shall be permitted in a mudflow area only if the applicant
demonstrates that the development cannot avoid such areas, and the
development adequately employs construction stabilization, and mitigation and
maintenance measures as designed by a qualified professional engineer, or
qualified professional geologist, and as approved by the County.
Development Over Faults
According to the LUDC, development shall be permitted over faults only if the
applicant demonstrates that such areas cannot be avoided and the development
complies with mitigation measures based on geotechnical analysis and
recommendations, as certified by a qualified professional engineer, or qualified
professional geologist, and approved by the County.
J. Radioactive Area.
Under LUDC ARTICLE 4, Section 4-203 G. Impact Analysis, Item 6.
Environmental Impacts. D. "Evaluation of any potential radiation hazard that may
have been identified by the State or County Health Departments." Under LUDC
Section 15-102. Definition of Words and Phrases, a Radioactive Area is defined
as "An area subject to various types of radiation emission from radioactive
minerals that occur in natural or manmade deposits of rock, soil, or water."
K. Potentially Unstable Soils.
According to the LUDC, Potentially Unstable Soils are defined as "An area of
land identified as having soils that may cause damage to structures, such as
buildings and roadways, as a result of over saturation or some other outside
influence." (LUDC Section 15-102. Definition of Words and Phrases).
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2.2 Garfield County Natural Hazard Mitigation Plan
In February 2012, Garfield County prepared a Natural Hazard Mitigation Plan that provides a set
of actions to plan for natural hazards and to mitigate their impact to the citizens, property, and
environment of Garfield County. The plan divides the county into five areas, with the western
part designated Area 5. The mission of the plan is to reduce risk to life and property.
2.3 Battlement Mesa Community PUD Phase II Project and Site Description
The proposed BM PUD Phase II Sites are located within the platted community limits of
Battlement Mesa, Colorado as shown in the Project Overview Map. The Sites are to be located
in proximity to existing development in Battlement Mesa community. The following sections
provide information about the proposed development and the site geologic setting.
2.4 Structural Geology
The BM PUD Phase II natural gas well pads, water storage pad, and pipeline sites are located
in the southeastern part of the Piceance Basin. The Piceance Basin is an irregularly-shaped
elongated basin formed by tectonic forces associated with the Laramide orogeny. These forces
down warped the earth's crust and formed the Piceance Basin as a result of the uplift of the
surrounding Colorado Rocky Mountains and the Colorado Plateau.
The Piceance Basin is the major structural geologic feature in the region. It is bound to the east
by the Grand Hogback monocline, the White River Uplift to the northeast, the Gunnison Uplift to
the south, the Uncompahgre Uplift to the south and southwest, the Douglas Creek Arch to the
west-northwest, and the axial basin uplift to the north (Grout and Verbeek, 1992).
Sedimentary rocks in the southwestern Piceance Basin gently dip to the north - northeast
except where this regional dip is interrupted by low -amplitude folds. Numerous small sub -
parallel northwest trending folds have been identified in the Green River Formation within the
basin.
There are no mapped faults shown in the area of the Sites on the Geologic and Structure Map
of the Grand Junction Quadrangle, Garfield County, Colorado (Cashion, 1973) or on the
Preliminary Geologic Map of the Grand Valley Quadrangle, Garfield County, Colorado (Donnell,
Yeend, Smith, 1986). A fault is a fracture in rock along which movement has occurred.
The Colorado Rocky Mountains are bound by faults; however, these faults are not always
visible at the ground surface either because the fault trace is `blind' meaning that the fault does
not have surface expression since it does not cut across overlying sedimentary bedrock units, or
that it has been buried and concealed by unconsolidated sediments deposited over the area
where the faults are present. There are no known major faults that have been mapped in the
area of the Sites.
2.5 Geology
Geologic units at each of the Sites are shown on the individual Surface Geology Maps.
According the Preliminary Geologic Map of the Grand Valley Quadrangle (Donnell, Yeend,
Smith, 1986), bedrock mapped in the project area consists of the Eocene and Paleocene -age
Shire Member of the Wasatch Formation which consists of purple, lavender, gray, and brown
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claystone, with minor beds of fine- to medium -grained sandstone. The maximum exposed
thickness of the Wasatch is approximately 1,200 feet.
The Tertiary age Wasatch bedrock in the area of the Sites is covered with unconsolidated
sediments of Quaternary age including alluvial terrace and fan gravel deposits, mud flow and
fan gravel deposits, alluvial and floodplain deposits, and modern alluvium. Weak claystone in
the Shire Member of the upper Wasatch Formation is responsible for slope failure which
resulted in slides and debris flows during the Pleistocene epoch of the Quaternary period at a
time when the climate was much wetter and colder. The Pleistocene epoch, often colloquially
referred to as the Ice Age, lasted from approximately 2,588,000 years ago to 11,700 years ago
and was characterized by the most recent global period of repeated glaciations.
Alluvial terrace and fan gravel deposits (Qla), consist of grayish brown, sandy gravel of basalt,
and locally derived slabby siltstone, marlstone, and sandstone; moderately to poorly sorted;
poorly stratified; rock fragments, angular to well rounded, and having a maximum thickness of
200 feet, or 61 meters. The proposed BMC L pad; Phase 11 pipeline segment sites, located in
Section 8, Township 7 South, Range 95 West, is underlain by this unit.
The Pleistocene mudflow and fan gravel deposits (Qgmf) consist of pebble, cobble, and boulder
gravel in a gray matrix of coarse sand. The unit is poorly sorted, contains angular to subangular
clasts of primarily unweathered basalt, but does contain some sandstone, marlstone, siltstone,
and claystone. The unit was largely derived from solifluction deposits located to the east of the
quadrangle. Solifluction deposits gradually move down slope, especially where a frozen subsoil
acts as a barrier to the percolation of water. The BMC A pad and Phase II pipeline segments in
Sections 13 and 24, Township 7 South Range 96 West, and the BMC F water storage pad in
Sections 16 and 18, Township 7 South, Range 95 West are underlain by mudflow and fan
gravel deposits.
Younger, Holocene deposits of modern alluvium, alluvial, and floodplain deposits (Qal and Qalc)
consisting of mud, silt, sand, and gravel are also present along the Colorado River drainage
covering the fan gravel deposits in the vicinity of the Sites. The alluvial and floodplain sediments
are locally derived from coalescing fan deposits and sheet -wash deposits from terraces along
the active Colorado River drainage, and also contain well-rounded, well -sorted, non -locally
derived crystalline rocks transported from areas to the east. The gravel commonly ranges in
thickness from 10 feet to 60 feet thick; however, it is locally up to 100 feet thick, especially near
the Colorado River (Yeend, 1969).
2.6 Soil
The individual Soils Maps, based on Natural Resources Conservation Service (NRCS) data,
show the area soil types present at each of the proposed Sites. Soils, consisting of the following
units, are within the study area around BM PUD Phase 11 well pads, water storage pad, and
Phase II Pipelines:
• Arvada Loam, 6% to 20% slopes, Map Symbol 4: The Arvada loam is a deep, well
drained sloping soil formed on fans and high terraces at elevations ranging from 5,100
feet to 6,200 feet amsl. The Arvada loam is derived from highly saline alluvium
consisting of sandstone and shale. The surface layer is typically a moderately alkaline,
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pale brown loam about 3 inches thick. The subsoil is brown silty clay loam about 14
inches thick, and the substratum is a light brown or brown silty clay loam to a depth of 60
inches. Permeability is very slow, and the available water capacity is high. Organic
matter content in the surface layer is low. The surface erosion hazard is moderately
rapid, and the erosion hazard is severe.
• Ildefonso stony loam, 6% to 25% slopes, Map Symbol 33, and 25% to 45%, Map Symbol
34: These soil units are deep, well drained, moderately sloping, hilly, to steep soils found
on mesa breaks, valley sides, and alluvial fans at elevations ranging from 5,000 to 6,500
feet amsl. These soils formed in mixed alluvium derived primarily from basalt. The
surface layer is a brown stony loam about 8 inches thick, the underlying material is a
white, strongly calcareous stony loam to a depth of 60 inches. Permeability is
moderately rapid, available water capacity is low, the surface runoff is medium and the
erosion hazard is severe for these soils.
• Potts Loam, 6% to 12 % slopes, Map Symbol 56: The Potts loam is a deep, well
drained, moderately sloping to rolling soil formed on mesas, benches, and the sides of
valleys at elevations between 5,000 feet and 7,000 feet above mean sea level. The Potts
loam soil formed in alluvium derived from sandstone, shale, or basalt. Typically, the
surface layer is a brown loam about four inches thick, the subsoil is a reddish brown clay
about 24 inches thick, and the substratum is a pinkish white loam to a depth of 60
inches. Permeability is moderate, and available water capacity is high. Surface runoff is
medium, and the erosion hazard is severe.
• Potts Ildefonso complex, 12% to 25% slopes, Map Symbol 58: Strongly sloping to hilly
soils on mesas, alluvial fans, and the sides of valleys at elevations ranging from 5,000
feet to 6,500 feet amsl. As stated above, the Potts loam was formed in alluvium derived
from sandstone, shale, or basalt; while the Ildefonso soil formed in very strongly
calcareous, basaltic alluvium with small amounts of eolian material. Permeability of the
Potts loam is moderate, and the available water capacity is high. Surface runoff is
medium, and the erosion hazard is moderate. Permeability of the Ildefonso soil is
moderately rapid and the available water capacity is low. Surface runoff is medium for
the Ildefonso soils, and the erosion hazard is moderate.
The Arvada loam, Ildefonso soils, and Potts loam soil are corrosive to uncoated steel and low to
moderately corrosive to concrete. Salinity ranges from 2 millimohs per centimeter (mmohs/cm)
to less than 4 mmhos/cm. Community development over these soil types is limited by low
strength, shrink -swell potential, large stones, and slopes. Buried piping and structures onsite will
need to have adequate cathodic protection to prevent corrosion due to the salinity of these soils.
Slopes should be protected to prevent erosion.
2.7 Hydrologic Setting
The Sites are located on a terrace at elevations of approximately 180 feet to 800 feet above the
Colorado River flood plain. The Colorado River is located between approximately 1/8 -mile to
over a mile and a half to the north-northwest of the Sites. The Monument Gulch creek drainage
is located approximately 1,000 feet to the east of the BMC A pad Site. These surface water
features are shown on the individual Surface Water and Water Well Maps.
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2.8 Aquifers
The Wasatch Formation locally yields water to wells in some areas, but is generally considered
a confining unit. The Tertiary sedimentary rocks in the Piceance Basin are generally fine-
grained and well cemented resulting in very low hydraulic conductivity in the rock matrix.
Sandstone and siltstone generally occur in lenticular bodies and locally have moderate hydraulic
conductivities ranging from 0.001 feet per day to 0.01 feet per day. These lenses of sandstone
and siltstone are often widely spaced and not interconnected which further limits the volumes of
groundwater the formation can yield to wells. In some areas, fracturing during the structural
deformation that occurred when the Piceance Basin was uplifted and through dissolution of
cementing minerals has enhanced the permeability and hydraulic conductivity in parts of the
Piceance Basin aquifer system (Topper et al, 2003).
Water well depths in the area typically range from 250 feet to 300 feet below ground surface
(bgs) along the terraces above the Colorado River. Static water levels reportedly range between
20 feet and 60 feet bgs based on a review of permitted water wells in the vicinity of the Sites.
Surficial aquifers are present in the alluvium along the Colorado River and its major tributaries.
The depth to groundwater is expected to be less than 20 feet in close proximity to the Colorado
River. This alluvium is typically too thin, narrow, and discontinuous along tributaries to be
considered a major aquifer, although in some areas the alluvium is locally important as surficial
aquifers (Banta and Robson, 1995). Groundwater within the unconsolidated sediments in the
area of the proposed Sites is controlled by the thickness of the sediments and the depth to the
top of the Wasatch bedrock. The estimated groundwater flow direction in the vicinity of the Sites
is likely to be sub -parallel with the Colorado River, flowing north-northwest toward the Colorado
River through the center and northern part of the proposed Sites. These deposits are shown on
the individual Surface Geology Maps.
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3.0 NATURAL AND GEOLOGIC HAZARD ASSESSMENT
The following sections present the assessment of geologic hazards in the vicinity of the
proposed well pads, water storage facility, and Phase II pipelines. The Battlement Mesa PUD
Phase II Vicinity Map shows the location of the BM PUD Sites in relation to the surrounding
parcels and local roads.
3.1 Utilities
Above -ground utility facilities located in Hazard Areas are to be protected by barriers or
diversion techniques approved by a qualified professional engineer. Above -ground utilities are
not expected to be required at the proposed facilities. The determination to locate utility facilities
above ground will be based upon the recommendation and requirements of the utility service
provider and approved by the County. Except for potential flash flooding, above -ground utilities,
such as transformers, are not expected to be affected by geologic or other natural hazards.
Trenches for water pipelines and natural gas pipelines are expected to be associated with the
proposed development. The slopes of the Arvada loam, Ildefonso stony loam, Potts loam, and
Potts-Ildefonso complex soils may pose technical challenges to the installation of these utilities;
however, it is expected that these limitations can be overcome with proper design and
installation.
Housing and community infrastructure developments are located to the north, south, east, and
west of the Sites. The Battlement Mesa waste water treatment facility is located to the north of
the BMC A pad Site off River Bluff Road. An easement for overhead powerlines is located to the
west of the BMC L pad south of North Battlement Parkway.
3.2 Avalanche Hazard Area
Winters are cold in the mountainous areas of Garfield County, and valleys are colder than the
lower parts of adjacent mountains due to cold air drainage. Average seasonal snowfall in
Garfield County is 50 inches. The greatest snow depth at any one time during the period of
record from 1951 to 1974 was 29 inches recorded at Rifle, Colorado approximately 25 miles to
the east-northeast of the proposed Sites.
Avalanches are not expected to affect the proposed natural gas well sites or pipelines located at
elevations of approximately 5,200 feet and 5,800 feet amsl. Areas in eastern Garfield County
are at higher elevations; receive more snow pack, and are therefore, more prone to avalanches
in certain years.
Avalanches are the most dangerous geologic hazard in Colorado resulting in injuries, loss of
life, and about $100,000 in direct property damage, and indirect economic losses in the millions
of dollars annually. However, the avalanche prone areas include the Park Range and Flat Tops
in northeastern Garfield County, Colorado, to the north of Glenwood Springs. Glenwood
Springs, near the east edge of the area, averages about one degree cooler than Rifle and
receives about five inches more precipitation per year (Harman and Murray, 1985).
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3.3 Landslide Areas or Potential Landslide Hazard Areas
The Sites are located on alluvial terrace, fan gravel, and mudflow deposits of Pleistocene -
Quaternary age. According to the Garfield County Natural Hazard Mitigation Plan, the overall
relative risk ranking due to landslides in Area 5 is 10% or a hazard index of 0.33. There are
earthflow and soil creep deposits mapped to the south of the Sites in southern half of Section
19, but these deposits are not mapped in Sections 16 or 18, Township 7 South, Range 95 West.
Movement of the extensive earthflow and soil creep slopes has ceased, except for local
occurrences of very recent slumps and mudflows. Solifluction deposits are extensive in the
Rulison 7.5 -minute quadrangle located to the east, but are only found in a small area on the
east side of the Parachute (Grand Valley) 7.5 -minute quadrangle (Yeend, Donnell, Smith,
1986).
According to Map 24 — Surface Geology map, Geologic Hazards Identification Study (Lincoln
Devore, 1975-1976), landslide areas are shown to the north of Interstate 70 in the Parachute —
Battlement Mesa area, but the mapping did not extend to the south of the highway. Landslide
areas are shown to the northwest of the town of Parachute (Garfield County, Surface Geology,
2007).
3.4 Rockfall Areas
The Sites are not located within areas that are prone to rockfall or potential for rockfall.
Potential rockfall areas are present along the steep drainages incised by Monument Creek to
the south and southeast or at higher elevations to the south on Battlement Mesa.
3.5 Alluvial Fan Hazard Areas
The Sites are not mapped within the alluvial fan hazard area according to the Garfield County
Surficial Geology, 2007. However, the Sites are located on an alluvial terrace underlain by fan
gravel deposits and mudflow according to the Preliminary Geologic Map of the Grand Valley
Quadrangle (Donnell, Yeend, Smith, 1986). The prehistoric mudflows and fan gravels are
associated with the Battlement Creek drainage located approximately 2.5 miles to the northeast.
These fan gravel and mudflow deposits lie about 100 feet above the modern Colorado River
flood plain.
3.6 Unstable or Potentially Unstable Slopes
According to the Garfield County Natural Hazard Mitigation Plan, the overall relative risk ranking
due to slopes in Area 5 is 31% or a hazard index of 1.17. Any risk ranking above 1 is considered
high risk. According to the Garfield County Slope Hazard Study Areas 1, 2, & 3 map, parts of
the area north of the Colorado River and the town of Parachute, Colorado have been mapped
as being in an area of major slope hazard. The map does not show the area south of the
Colorado River and in the vicinity of the Sites as being identified in a slope hazard area.
According to the Garfield County Natural Hazard Mitigation Plan (February 2012), steep ravines
and narrow valleys characterize the western part of Garfield County (Area 5). In and among the
landscape are the wells and pipelines that are the underpinning of the County economy. In the
steeper areas of western Garfield County landslide, debris flow, rock falls, and soil instability
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due to the steep slopes pose a risk to these assets. This is not the case in the BM PUD Phase II
development area.
The slope hazard map recommends that site-specific investigations should be conducted to
assess active landslide areas. Geologic studies may include intensive drilling and sophisticated
strength testing, stability analyses, and monitoring of soil, rock, and groundwater conditions.
Mitigation may be possible, but likely will be expensive, may require special siting, and will
involve some risk. Avoidance may be recommended for projects of lower economic value
(Garfield County, Slope Hazard Study 2002).
The soils in the area are formed in areas with 6% to 12% slopes (Potts loam, soil unit #56), 6%
to 20% slopes (Arvada loam, unit symbol #4), 6% to 25% and 25% to 45% slopes (Ildefonso
stony loam, unit symbols #33, #34), and 12% to 25% slopes (Potts-Ildefonso complex, soil unit
#58). Engineering, design, and construction practices of the proposed facility pad developments
are expected to mitigate the limitation of slopes at the Sites. The Sites are located within an
area developed for other land uses, including housing and commercial developments and public
infrastructure located to the north, south, east, and west of the proposed BM Phase II PUD
facility pads and pipeline segments.
The proposed BMC A pad location, BMC A UIC, and BMC A pipeline are in an area where the
elevation rises 140 feet over a distance of approximately 310 feet, and is underlain by the
Ildefonso stony loam (unit symbol #34). Cut and fill slopes are planned during construction with
a finished grade across the BMC A pad of 1%. RJ Engineering & Consulting, Inc. of Glenwood
Springs prepared a Geotechnical Consultation for the BMC A pad dated April 11, 2017, updated
in July 2017, that recommended a nail wall for the proposed cut depths of 30 feet. SGM of
Glenwood Springs, Colorado prepared a Drainage Report for the BMC A pad dated July 2017
that has recommendations for on-site and off-site drainage, as well as stormwater detention. If
groundwater is encountered slope drains should be installed within the fill slope as seepage is a
limitation for development in areas with the Ildefonso soils. Equipment, production and UIC
wellheads will be located toward the cut slope on the pad and placing loads on the fill slope
should be avoided.
The BMC A pipeline should be constructed to select the best available vertical and horizontal
alignment within the proposed right-of-way, and use best management practices (BMPs) to
prevent erosion. These may include sediment barriers, interceptor dikes, trench plugs, trench
dewatering, diversion ditches, sediment basins, and seeding and revegetation.
The proposed BMC F pad location is in an area where the change in elevation rises 40 feet over
a distance of approximately 800 feet. A tributary to Monument Gulch is located to the south. The
site is underlain by the Ildefonso stony loam (unit symbol #33) with 6% to 25% slopes, and the
Potts-Idelfonso complex (unit symbol #58) with 12% to 25% slopes. Produced water storage
tanks will be placed toward the cut slope side of the BMC F pad and loading on the fill slope
should be avoided. If groundwater is encountered slope drains may be required since seepage
is a limitation to development for the Ildelfonso soils. SGM of Glenwood Springs, Colorado
prepared a Drainage Report for the BMC F pad dated July 2017 with recommendations for on-
site and offsite drainage as well as stormwater detention.
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The proposed BMC L pad location is in an area where the elevation rises 60 feet over a
distance of approximately 1,600 feet. Soils underlying this site are mapped as Potts loam (unit
symbol #56) with 6% to 12% slopes, interfingered with the Potts-Ildefonso soils (unit symbol
#58) with 12% to 25% slopes. SGM of Glenwood Springs, Colorado prepared a Drainage
Report for the BMC L pad which discusses off-site drainage, on-site drainage, and stormwater
detention. Ursa's stormwater management plan (SWMP) provides BMP details.
3.7 Corrosive or Expansive Soils and Rock
According to the Garfield County Natural Hazard Mitigation Plan, the overall relative risk ranking
of asset risk from soils in Area 5 is 5% or a hazard index of 0.18. According to the Soil Survey of
the Rifle Area, the Potts loam soils are corrosive to unprotected steel and moderately corrosive
to concrete. Sedimentary rock containing high salt content, such as chloride or sulfate, and soils
derived from these rock types, may also be corrosive to concrete or metal, causing damage to
structures built upon them. The Arvada, Potts, and Ildefonso soil types are slightly acidic to
alkaline with pH ranging from 6.6 to more than 8.4 standard units. The salinity in these soils
typically ranges from less than 2 mmhos/cm to less than 4 mmhos/cm.
Some Tertiary and Cretaceous age sedimentary rocks with high clay content are capable of
accepting water into their chemical structure and expanding many times their volume when dry.
These sedimentary rocks, and soils formed from these rock types, may expand or contract as
they become wet and then dry out resulting in damage to structures built upon them. The shrink
swell potential of the Arvada loam is severe, while the shrink -swell potential of the Ildefonso and
Potts soil is considered low to moderate.
The proposed BMC A pad, BMC A UIC pad, and BMC A pipeline are located in an area
underlain by the Ildefonso stony loam (unit symbol #34) and adjacent to an area underlain by
the Arvada loam (unit #4). If Arvada loam soils are encountered on the location construction
may require the use of geotextile fabrics or lined secondary containment for the tanks to
address the shrink -swell potential issues. There may be a higher potential for shrink -swell
issues near the toe of the fill slope where Arvada loam soils are present. Pipeline joints should
be able to relieve stress and strain from expansive soils, or when transitioning from one soil type
to another. Both the BMC A pipeline and BMC L Pipelines should be coated or protected with
cathodic protection to prevent corrosion.
3.8 Mudflow and Debris Fan Areas
The Sites are located in an area of Pleistocene age mud flow and fan gravel deposits partially
overlain by alluvial terrace deposits. The Sites are located on a terrace near the Colorado River
drainage. These prehistoric deposits are Holocene in age and future mud slides are a potential
hazard if the area were to receive heavy rains. These flows are expected to originate from
higher elevations to the south and would follow the drainages to lower elevations closer to the
Colorado River floodplain.
Wetter conditions at the end of the last ice age were most likely responsible for the development
of the extensive mudflows and fan deposits peripheral to Battlement Mesa and were deposited
by historic flows from Battlement Creek. Glacial conditions that existed on the Grand Mesa
during the Pleistocene did not exist on Battlement Mesa at this time. Abundant annual runoff is
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suspected in creating high pore -water pressures within the Wasatch Formation shale and
claystone to cause slope failure, especially on north -facing slopes where evaporation was at a
minimum (Yeend, 1968). More recent slumps and mud flows have occurred south of Plateau
Creek near the town of Collbran. These slumps and mud flows developed in glacial till.
According to the Garfield County Natural Hazard Mitigation Plan, the overall relative risk ranking
of the asset risk from debris flow in Area 5 is 1% or a hazard index of 0.05.
3.9 Development Over Faults and Risk of Seismic Activity
Most earthquakes or seismic events occur as the result of natural geologic phenomena, such as
displacement along faults or due to volcanic activity. The Dotsero Crater located in Eagle
County to the east of Garfield County is one of several volcanic features resulting from basaltic
eruptions between 3,800 and 5,500 years ago. The hot springs in Glenwood Springs are the
result of geothermal activity where groundwater is heated by rocks overlying magma and the hot
water circulates back to the surface.
The Piceance Basin and other Tertiary age basins of the Colorado Plateau are defined by
monoclines, at least along one margin. The Grand Hogback, to the east near the town of Rifle,
is such a monocline which is thought to have formed by reactivation of pre-existing, steeply
dipping fault zones in the Precambrian basement rock. Recent seismic data suggests that some
of the monoclines, especially in the Rocky Mountain foreland near the boundary with the
Colorado Plateau, overlie a west-, southwest-, or south -directed thrust fault system. These blind
thrust faults transect older Mesozoic and Paleozoic sedimentary rocks that resulted from two
major deformational events associated with the uplift of the ancestral Rocky Mountains. The
Grand Hogback monocline formed above the tip of a blind, Precambrian basement rock thrust
fault wedge which moved southwest and west-southwest into the Piceance basin (Grout and
Verbeek, 1992).
There are no major faults shown in the Grand Valley area on the Geologic and Structure Map of
the Grand Junction Quadrangle, Colorado and Utah (Cashion, 1973). There are no mapped
faults shown on the Preliminary Geologic Map of the Grand Valley Quadrangle, Garfield County,
Colorado (Donnell, Yeend, and Smith, 1986) in the immediate vicinity of the Sites.
Colorado is considered a region of minor earthquake activity; however, there is uncertainty due
to the relatively short historic record. According to the USGS Colorado Earthquake History
online, newspaper accounts were the primary source of earthquake data in Colorado prior to
1962. Few earthquakes have been reported in this part of Colorado. A very minor earthquake
occurred in the northwestern part of Colorado on November 22, 1982 at 3:09 a.m. MST. The
magnitude 2.9 earthquake was located about 18 miles northeast of the town of Rifle and was
felt at a fish hatchery in the area.
A 4.3 magnitude earthquake occurred on January 7, 1971 south of Glenwood Springs at a
depth of 33 kilometers. A swarm of earthquakes occurred in the Carbondale area, the largest
occurred on April 22, 1984 and had a magnitude of 3.1 on the Richter scale. The quake was felt
in Carbondale and in Glenwood Springs, and of the hundreds of quakes that occurred in the
Carbondale area during that time period, 12 were reported as felt. In August 2001, a 4.0
magnitude earthquake was recorded five miles north of Glenwood Springs. A 3.8 magnitude
earthquake was felt near New Castle and Silt in February 2006.
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A 2.2 magnitude earthquake occurred in October 2016, and a 2.9 magnitude occurred on
December 25, 2016 near New Castle. A 3.3 magnitude earthquake occurred on January 30,
2017 approximately 5 kilometers south of New Castle at a depth of 5 kilometers. A swarm of 11
earthquakes occurred in the Marble area ranging from 1.1 to 2.8 in magnitude.
There have been cases where seismicity has been shown to be triggered by human activity
through injection of fluids into the subsurface. Induced seismicity is defined as a phenomenon
caused by human activities, such as injecting waste water into Underground Injection Control
(UIC) wells causing a release of energy within the earth. The concept of human induced
seismicity was first proposed in connection with earthquakes resulting from the injection of
chemical weapon waste fluids at the Rocky Mountain Arsenal near Denver in the 1960s and
1970s. More recently injection of waste water from oil wells in northcentral Oklahoma has
resulted in earthquakes. Most induced seismicity events are very small. Citizen activist groups
asked Colorado oil and gas regulators to determine if nearby injection wells were causing the
recent seismic activity in the Silt — New Castle area.
Julie Dutton, a geophysicist with the National Earthquake Information Center, doubted a
connection with injection operations and the seismic activity. The area is known to have
infrequent earthquakes. There are relatively few earthquakes in Garfield County, and currently it
does not appear that seismic activity is increasing in frequency. An estimated 30,000
earthquakes occur annually worldwide with magnitudes ranging from 2.5 to 5.4 (Denver Post,
Post Independent articles).
3.10 Flood Prone Areas
The BMC A pad, BMC A UIC pad, BMC A pipeline, BMC L pad, BMC L pipeline, and BMC F
pad locations are not located within the floodplain. According to the Garfield County Natural
Hazard Mitigation Plan, the overall relative risk ranking due to floods in Area 5 is 23% or a
hazard index of 1.09. Olsson conducted a review of the FEMA 100 -year flood hazard zone in
the Vicinity of the Town of Parachute and Battlement Mesa, Garfield County, Colorado, or a
Firmette Map generated from the FEMA data. The Colorado River flood plain is located several
hundred feet to the north of the Sites at an elevation that is approximately 180 feet lower than
that of the lowest Site elevation, BMC A Well pad. Monument Creek and the unnamed
drainages to the northeast and the southwest are shown as having Zone A — 100 -year flood
plains located along their banks. These areas are also prone to flash floods. RJ Engineering &
Consulting, Inc. prepared a Geotechnical Consultation for the BMC A pad, and SGM prepared a
Drainage Report for the BMC A, BMC L, and BMC F pads for the 2 -year, 25 -year, and 100 -year
storm events using National Oceanic Atmospheric Administration (NOAA) Atlas information to
calculate runoff and size stormwater detention ponds. The flood plain along the Colorado River
is shown in relation to the BM PUD Phase II Sites on the attached Flood Plain Map.
3.11 Collapsible Soils
Collapsible soils are another type of subsidence that occurs in parts of western Colorado where
unconsolidated sediments are present. This ground settlement can damage man-made
structures such as foundations, pavements, concrete slabs, utilities, and irrigation works.
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Collapsible soils have not been mapped in the area and are not expected to be encountered in
the vicinity of the Sites.
3.12 Mining Activity
A review of the Grand Valley 7.5 -minute quadrangle did not show any significant mining
activities in close proximity to the proposed BM PUD pad Sites. Oil shale mining was conducted
north of the town of Parachute, and there are sand and gravel operations along the Colorado
River. There are no mining activities shown in the immediate area of the Sites.
3.13 Radioactivity
Naturally occurring radioactive materials are not expected to be an issue at the Sites. Colorado
oil and gas operations are not known to have a significant problem with naturally occurring
radioactive materials (NORM) or technologically enhanced naturally occurring radioactive
materials (TENORM); however, there have been some instances where pipe scale has
contained radium and associated radon gas. Since the sites are not continuously occupied, a
NORM survey, including site-specific testing, is not necessary. A NORM survey could be
performed to further assess the radon potential at the Sites to serve as a baseline assessment if
used pipe or pipe scale is to be disposed offsite in the future.
Olsson reviewed the Colorado Bulletin 40, Radioactive Mineral Occurrences of Colorado which
states that nearly all of Garfield County's uranium production came before 1954, and most of
that came from the Rifle and Garfield mines. Both of these mines were located along the same
ore body near the town of Rifle. These occurrences were all hosted in the Jurassic Morrison and
Entrada Formations, and the Triassic -Jurassic Navajo Sandstone, or the Triassic Chinle
Formation which are known to contain uranium and vanadium deposits in the county and in the
Colorado Plateau in general (Nelson -Moore, Collins, and Hornbaker, 1978). These formations
lie at great depth in the vicinity of the Sites and are stratigraphically below the depth of the
Wasatch Formation.
The Colorado Department of Public Health and Environment (CDPHE) has posted a statewide
radon potential map on their website based on data collected by the EPA and the U.S.
Geological Survey. Garfield County and most of Colorado has been mapped as being within
Zone 1 — High Radon Potential, or having a high probability that indoor radon concentrations will
exceed the EPA action level of 4 picocuries per liter (pCi/L).
Radon is not expected to be a significant problem at the proposed Sites since the development
will not include any permanent structures, personnel will not be onsite for extended periods, and
the Sites will not be developed with structures containing basements or substructures in which
radon can accumulate.
Geologic and Natural Hazard Report
Ursa Operating Company BM PUD Phase II
Garfield County, Colorado - July 2017 rev
18
Olsson Associates
Golden, Colorado
Project #016-3531
4.0 Conclusions and Recommendations
The following conclusions and recommendations were made following a review of the available
Site data for natural and geologic hazards in the vicinity of BM PUD Phase II pad and pipeline
segments located in Garfield County, Colorado.
• Geological hazards are not expected to be associated with the installation of buried
utilities at the BM PUD Phase II pad and pipeline sites. Pipeline joints should be
designed to accommodate stress and strain resulting from slopes and shrink -swell of
soils, or transition from one soil type to another. The use of stormwater BMPs to prevent
erosion and sediment transport will be used during construction. Corrosive soil may be a
limitation to this construction, but this limitation should be able to be mitigated with
proper engineering, design, and construction. Coatings and cathodic protection for
buried piping may reduce corrosion resulting from salts in these soils.
• Avalanche conditions are not expected to be a hazard in the area of the Sites.
• The Sites are located on an alluvial terrace and underlain with Pleistocene age mud flow
and fan gravel deposits. The Sites are within the limits for the Battlement Mesa PUD,
and there are housing developments to the east, northeast, and southeast of the Sites.
The mud flow, terrace, and fan gravels are not expected to constitute a geologic hazard
for the BM Phase II PUD pad and pipeline development.
• Rockfall areas are not present in the area of the Sites, and are not expected to be a
geologic hazard affecting the proposed Sites. Rockfall hazard areas are present to the
south at higher elevation on Battlement Mesa.
• The Sites are not in an alluvial fan hazard area; however, the BMC A pad site is
underlain by alluvium and fan gravels. The BMC F pad and BMC L pad sites are
underlain by Pleistocene age mud flow and fan gravels that were deposited during
prehistoric times from floods associated with Battlement Creek. Alluvial fans have been
deposited at the mouths of Battlement Creek, Monument Gulch, and other nearby
streams.
• Slope is a not expected to be a geologic hazard affecting development of the BM PUD
pad Sites as long as the slopes are less than 20%. If development occurs on slopes of
between 20% and 25% additional engineering and design may be needed. RJ
Engineering of Glenwood Springs prepared a Geotechnical Consultation for the BMC A
pad, and SGM of Glenwood Springs prepared Drainage Reports for the BMC A, BMC F,
and BMC L pads.
• The Arvada, Ildefonso, and Potts loam soils are corrosive to unprotected steel and
moderately corrosive to concrete. The Arvada loam soil, present on part of the BMC A
pad has a high shrink -swell potential. The Ildefonso stony loam contains large rocks.
The Potts loam, Ildefonso stony loam, and the Potts-Ildefonso complex soils are listed as
having low to moderate shrink -swell potential, so expansive soils are not expected to
pose a hazard affecting the proposed BM PUD pad sites. Cathodic protection is needed
for the pipelines to prevent corrosion.
• Collapsible soils are not present in the vicinity of the proposed BM PUD pad sites.
Geologic and Natural Hazard Report
Ursa Operating Company BM PUD Phase II
Garfield County, Colorado - July 2017 rev
19
Olsson Associates
Golden, Colorado
Project #016-3531
• No significant faults have been mapped or are known in the BM PUD Phase 11 pad sites.
Earthquakes have been recorded in the eastern part of Garfield County, but have not been
recorded in the Battlement Mesa area.
• The BM Phase 11 pad and pipeline sites are not mapped as being within the 100 -year
flood plain. Flash flooding is a hazard for lower elevations along the unnamed drainages
to the east and southwest of the proposed Sites and along the Colorado River. Areas
immediately adjacent to these streams are located within the 100 -year flood plain and
are prone to flood risks. SGM prepared Drainage Reports for the BMC A, BMC L, and
BMC F pads and calculated the stormwater runoff for a 2 year, 25 year, and 100 year
storm event to calculate the volume needed for stormwater detention ponds.
• There are no mining activities shown in the vicinity of the Sites. Natural gas well drilling
has been conducted in the area since the 1960s.
• There are no significant radioactive mineral deposits known in the immediate area of the
Sites. The presence of NORM may be an issue with exploration and production and
could be an issue with used pipe scale or used equipment. Radioactive materials are not
expected to pose a significant hazard at the Sites. If elevated NORM wastes are
encountered, the NORM wastes will need to be disposed in accordance with applicable
state and federal regulations.
Geologic and Natural Hazard Report
Ursa Operating Company BM PUD Phase II
Garfield County, Colorado - July 2017 rev
20
Olsson Associates
Golden, Colorado
Project #016-3531
5.0 References
• Cashion, W.B., 1973, Geologic and Structure Map of the Grand Junction Quadrangle, Colorado
and Utah, USGS, Map 1-736, scale 1:250,000
• Donnell, J.R., Yeend W.E., Smith M.C., 1986, Preliminary Geologic Map of the Grand Valley
Quadrangle, Garfield County, Colorado, scale 1:24,000
• Grout, M. A. and Verbeek, E.R., 1992, U.S.G.S. Bulletin 1787-Z, Fracture History of the Divide
Creek and Wolf Creek Anticlines and Its Relation to Laramide Basin -Margin Tectonism, Southern
Piceance Basin, Northwestern Colorado, 32 p.
• Harman, J.B. and Murray, D. J., 1985, Soil Survey of Rifle Area, Colorado, Parts of Garfield and
Mesa Counties, Colorado: U.S. Department of Agriculture, Soil Conservation Service, in
cooperation with the Colorado Agricultural Experiment Station, 149 p. two plates, and 20 map
sheets.
• Nelson -Moore, J.L., Bishop Collins, D., Hornbaker, A.L., 2005, Colorado Geologic Survey, Bulletin
40, Radioactive Mineral Occurrences of Colorado, pp 154-158 (CD)
• Robson, S.G. and Banta, E.R., 1995, U.S.G.S. Hydrologic Investigations Atlas 730-C, Groundwater
Atlas of the United States, Segment 2, Arizona, Colorado, New Mexico, Utah, 32 p.
• RJ Engineering & Consulting, April 11, 2017, updated July 2017, Geotechnical Consultation BMC
A Pad in Garfield County, Colorado letter to SGM, Inc., 2 p.
• SGM, Drainage Report, Ursa Operating Company, BMC A Pad, July 2017, 13 p.
• SGM, Drainage Report, Ursa Operating Company, BMC F Pad, July 2017, 18 p.
• SGM, Drainage Report, Ursa Operating Company, BMC L Pad, July 2017, 18 p.
• Topper, R., Spray, K. L., Bellis, W.H., Hamilton, J.L., Barkman, P.E., Ground Water Atlas of
Colorado, Colorado Geologic Survey, 2003, Special Publication 53, 210 p.
• Yeend, W.E., 1969, Quaternary Geology of the Grand and Battlement Mesas Area, Colorado,
USGS Professional Paper 617, 50 p, 1 plate.
Online References
• Colorado Oil and Gas Conservation Commissionhttp://cogcc.state.co.us/
• Natural Resources Conservation Service - Soil Survey http://www.nrcs.usda.gov/
• Garfield County LUDC https://www.garfiled-county.com/community-
development/documents/land-use/Complete-Land-Use-and-Development-Code-07.15.2013.pdf
Natural Hazard Mitigation Plan (Green, et al) — February 2012
https://www.garfield-county.com/county-services/documents/Garfield-County-Hazard-Mitigation-
Plan.pdf
• Garfield County Geographic Information System: https//www.garfield-county.com/geographic-
information-systems/download-qis-data.aspx
• Colorado Geological Survey website: http://geosurvey.state.co.us/hazards
• Colorado Geological Survey website: http://geosurvey.state.us/land/Pages/Professional Geologist
• Colorado Department of Public Health and Environment: http://co-radon.info/CO radon map.html
• Denver Post, Garfield County's biggest earthquake in decade
http://www.denverpost.com/2017/01 /31 /garfield-county-earthquake-silt/
• Post Independent Yet another earthquake, Garfield County's biggest in decade, hits Silt
http://www. postindependent.com/news/yet-another-earthquake-biggest-one-lately-hits-silt/
Geologic and Natural Hazard Report
Ursa Operating Company BM PUD Phase 11
Garfield County, Colorado - July 2017 rev
21
Olsson Associates
Golden, Colorado
Project #016-3531
APPENDIX A — FIGURES
Battlement Mesa PUD Phase 11 Maps
Phase II Pads and Access Roads
Phase II Pipelines
Notes / Comments
3 -mile Buffer
Parcels
County Road
City Limits
Pad, Access Road, and Pipeline Source: River Valley Survey, Inc.
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa r.;r
Vicinity Map
Battlement Mesa PUD
Phase II
0 1,250 2,500 5,000
Feet
Battlement Mesa Planned Unit Development
Colorado River
Author: S. Stoddart
Revision: 0
Date: 1/11/2017
Proposed Pads and Access Roads
Proposed Pipelines
1/4 Mile Buffer
Stream / River
Perennial Stream
Intermittent Stream
Ditch / Canal
• Water Wells (all applications)
Notes / Comments
Pad, Access Road, and Pipeline Source: River Valley Survey, Inc.
Hydrography Source: USGS
Water Well Source: CDWR
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographic,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
112 Ursa
Surface Water and Water Wells
Battlement Mesa PUD
Phase II
o 500 1,000 2,000
Feet
OLSSON
Author: S. Stoddart
Revision: 0
Date: 1/11/2017
Proposed Pads and Access Roads
Proposed Pipelines
100 -Year Flood Plain
Notes / Comments
Pad, Access Road, and Pipeline Source: River Valley Survey, Inc.
Flood Plain Source: Garfield County IT Department
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
1t'` Ursa
Flood Plain
Battlement Mesa PUD
Phase II
0 500 1,000 2000
Feet
O\OLSSONe n
Author: S. Stoddart
Revision: 0
Date: 1/11/2017
Proposed Pipelines
Proposed Pads and Access Roads
3 -mile Pipeline Buffer
Parcels
— County Road
Battlement Mesa Planned Unit Development
Parachute Town Limits
Colorado River
Notes / Comments
Pipeline Source: River Valley Survey, Inc.
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Vicinity Map
Battlement Mesa PUD
Phase II Pipelines
0 1,250 2,500 5,000
Feet -
N
OLSSON
Author: S. Stoddart
Revision: 0
Date: 2/14/2017
BMC A PAD
Proposed BMC A Pad and Access
3 -mile Buffer
Parcels
County Road
City Limits
Battlement Mesa Planned Unit Development
Colorado River
Notes / Comments
BMC A Source: River Valley Survey
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
ig?Ursa
ern,
ter
Vicinity Map
Battlement Mesa PUD
BMC A Pad
Section 18, Township 7 South, Range 95 West
Section 13, Township 7 South, Range 96 West
0 1,250 2,500 5,000
Feet
CY\OLSSON• n
Author: S. Stoddart
Revision: 0
Date: 1/3/2017
Proposed BMC A Pad and Access
t1•
Wasatch Formation (including
Fort Union equivalent at base)
and Ohio Creek Formation
[QA
Modern alluvium
Notes / Comments
BMC A Source: River Valley Survey
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
1 Ursa
Surface Geology
Battlement Mesa PUD
BMC A Pad
0 50 100 200
Feet
N
CY\OLSSON• n
Author: S. Stoddart
Revision: 0
Date: 12/29/2016
Proposed BMC A Pad and Access
4 Arvada loam, 6 to 20 percent slopes
• Ildefonso stony loam, 25 to 45 percent
slopes
0 Potts loam, 6 to 12 percent slopes
Potts-Ildefonso complex, 12 to 25
• percent slopes
Notes / Comments
BMC A Source: River Valley Survey, Inc.
Soils Source: U.S. Department of Agriculture, Natural Resources
Conservation Service
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
•�: `3WAIrs.
r.xwarv•
Soils
Battlement Mesa PUD
BMC A Pad
0
Feet
50 100 200
OLSSONJ n
Author: S. Stoddart
Revision: 0
Date: 12/29/2016
Proposed BMC A Pad and Access Roac
n1/4 Mile Buffer
Stream / River
Perennial Stream
Intermittent Stream
• Water Wells (all applications)
Notes / Comments
BMC A Source: River Valley Survey, Inc.
Hydrography Source: USGS
Water Well Source: CDWR
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographic,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
.itUrsa
Surface Water and Water Wells
Battlement Mesa PUD
BMC A Pad
o 125 250 500
Feet
OLSSON n
Author: S. Stoddart
Revision: 0
Date: 12/29/2016
Battlement Mesa Company
Maintenance Buildings - 94 feet
Water Treatment
Maintenance Building - 256 feet
Waste Water Treatment
Facilities - 80 feet
Proposed BMC A Pipeline
n Proposed BMC A Pad
n 200 -ft Pipeline Buffer
n 350 -ft Pipeline Buffer
nParcel Boundaries
Notes / Comments
Pipeline and Pad Source: River Valley Survey, Inc.
Parcel Source: Garfield County GIS
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
See attached list for land owners.
Ursa
Adjacent Land Owners
and Structures
Battlement Mesa PUD
BMC A Pipeline
0
Feet
125 250 500
OLSS9!
Author: S. Stoddart
Revision: 0
Date: 1/17/2017
240913406004
BATTLEMENT MESA
PARTNERS
240708100152
BATTLEMENT MESA
LAND INVESTMENTS
Proposed BMC A Pipeline
n Proposed BMC A Pad
nParcel Boundaries
Notes / Comments
Pipeline and Pad Source: River Valley Survey, Inc.
Parcel Source: Garfield County GIS
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Property Owners
Battlement Mesa PUD
BMC A Pipeline
Feet
0 75 150 300
• OLSSON s: A
Author: S. Stoddart
Revision: 0
Date: 1/19/2017
BMC F PAD
Illoui
iimk„,
1
Proposed BMC F Pad and Access
3 -mile Buffer
Parcels
County Road
Battlement Mesa Planned Unit Development
Parachute Town Limits
Colorado River
Notes / Comments
BMC F Source: River Valley Survey
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Sections
Ursa
Vicinity Map
Battlement Mesa PUD
BMC F Water Storage
16 and 17, Township 7 South, Range 95 West
0 1,250 2,500 5,000
Feet
OLSSON• n
Author: S. Stoddart
Revision: 0
Date: 2/14/2017
Proposed BMC F Pad and Access
EQ11
Landslide deposits
Notes / Comments
BMC F Source: River Valley Survey
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
1P Ursa
•
Surface Geology
Battlement Mesa PUD
BMC F Water Storage
0 50 100 200
Feet
OLSSON
Author: S. Stoddart
Revision: 0
Date: 12/29/2016
Proposed BMC F Pad and Access
Ildefonso stony loam, 6 to 25 percent
slopes
0 Potts loam, 6 to 12 percent slopes
Potts-Ildefonso complex, 12 to 25
percent slopes
Notes / Comments
BMC F Source: River Valley Survey, Inc.
Soils Source: U.S. Department of Agriculture, Natural Resources
Conservation Service
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Soils
Battlement Mesa PUD
BMC F Water Storage
0 50 100 200
Feet
OLSSONJ
Author: S. Stoddart
Revision: 0
Date: 12/29/2016
Proposed BMC F Pad and Access Road
n1/4 Mile Buffer
Intermittent Stream
• Water Wells (all applications)
Notes / Comments
BMC F Source: River Valley Survey, Inc.
Hydrography Source: USGS
Water Well Source: CDWR
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographic,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Surface Water and Water Wells
Battlement Mesa PUD
BMC F Water Storage
o 125 250 500
Feet
OLSSON .
Author: S. Stoddart
Revision: 0
Date: 12/29/2016
BMC L PAD
Proposed BMC L Pad and Access
— Proposed BMC L Pipeline
3 -mile Buffer (Pad/Acc)
Parcels
County Road
Battlement Mesa Planned Unit Development
Parachute Town Limits
Colorado River
Notes / Comments
BMC L Source: River Valley Survey
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa ,•
Vicinity Map
Battlement Mesa PUD
BMC L Pad
Section 8, Township 7 South, Range 95 West
0 1,250 2,500 5,000
Feet
CY\OLSSON • n
Author: S. Stoddart
Revision: 0
Date: 2/14/2017
Proposed BMC L Pad and Access
Proposed BMC L Pipeline
Wasatch Formation (including
VD Fort Union equivalent at base)
and Ohio Creek Formation
Notes / Comments
BMC L Source: River Valley Survey
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Surface Geology
Battlement Mesa PUD
BMC L Pad
0 50 100 200
Feet -
N
OLSSON
Author: S. Stoddart
Revision: 0
Date: 2/14/2017
Proposed BMC L Pad and Access
Proposed BMC L Pipeline
0 Potts loam, 6 to 12 percent slopes
Potts-Ildefonso complex, 12 to 25
percent slopes
Notes / Comments
BMC L Source: River Valley Survey, Inc.
Soils Source: U.S. Department of Agriculture, Natural Resources
Conservation Service
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa.
Soils
Battlement Mesa PUD
BMC L Pad
0 50 100 200
Feet -
N
OLSSON
Author: S. Stoddart
Revision: 0
Date: 2/14/2017
Proposed BMC L Pad and Access Road
Proposed BMC L Pipeline
1/4 Mile Buffer (Pad/Acc)
Intermittent Stream
• Water Wells (all applications)
Notes / Comments
BMC L Source: River Valley Survey, Inc.
Hydrography Source: USGS
Water Well Source: CDWR
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographic,
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Surface Water and Water Wells
Battlement Mesa PUD
BMC L Pad
o 125 250 500
Feet
OLSSON n
Author: S. Stoddart
Revision: 0
Date: 2/14/2017
Proposed BMC L Pad and Access Road
nAffected Parcels
Adjacent Parcels
Notes / Comments
BMC L Source: River Valley Survey, Inc.
Parcel Source: Garfield County GIS
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
See attached list for land owners.
Ursa. •
Adjacent Land Owners
Battlement Mesa PUD
BMC L Pad
Miles
0 0.125 0.25 0.5
OLSsASSO9N.
Author: S. Stoddart
Revision: 0
Date: 1/4/2017
Proposed BMC L Pipeline
Proposed BMC L Pad
nParcel Boundaries
Notes / Comments
Pipeline and Pad Source: River Valley Survey, Inc.
Parcel Source: Garfield County GIS
Imagery Source: Esri, DigitalGlobe, GeoEye, i -cubed, Earthstar Geographics
CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN,
IGP, swisstopo, and the GIS User Community
Ursa
Property Owners
Battlement Mesa PUD
BMC L Pipeline
0 100 200 400
Feet
OLSSON . n
Author: S. Stoddart
Revision: 0
Date: 1/19/2017
APPENDIX B — ADDENDUM
SEISMIC HAZARDS ASSOCIATED WITH THE
URSA OPERATING COMPANY, LLC
BMC A Pad Class 11
Underground Injection Control Activity
OAS OLSSON
ASSOCIATES
April 19, 2017
Addendum to the Geologic and Natural Hazards Report — April 2017
Seismic Hazards Associated with the Ursa Operating Company, LLC
BMC A Pad Class II Underground Injection Control Activity
Olsson Project #016-3531
Olsson reviewed available published geologic reports and maps for the proposed Ursa
Operating Company (Ursa) BMC A Pad Class II Underground Injection Control (UIC) well. The
proposed Battlement Mesa PUD BMC A Pad UIC well pad is located to the northeast of the
town of Parachute, Colorado off of County Road 307. The site is located in the SE 1/4 SE 1/4
Section 13, T7S, R96W, 6t" P.M. and is located in parcel # 240913406004 and 240708100152.
Injection Wells and Induced Seismicity
Most earthquakes or seismic events occur as the result of natural geologic phenomena. There
have been some cases where seismicity was suspected to have been triggered by human
activity, known as induced seismicity. Induced seismicity is defined as a phenomenon caused
by human activities, such as injecting wastewater into UIC disposal wells, which results in a
release of energy within the earth. Most induced seismicity is of a low magnitude.
Colorado is well known in earthquake literature for a swarm of earthquakes that occurred in the
late 1960s and were linked to operation of a deep chemical waste injection well by the Army
Corps of Engineers at the Rocky Mountain Arsenal near Denver, Colorado (McClain, 1970).
Studies have also been conducted in Colorado to control seismic activity by monitoring fluid
pressures and the quantities of fluid injected.
An experiment in earthquake control in Chevron Oil's Rangely oil field in Rio Blanco County
Colorado was performed by the Advanced Research Projects Agency of the Department of
Defense and USGS following the induced seismicity at the Rocky Mountain Arsenal. The
earthquakes were apparently triggered by high pressure injection of fluid into stressed rock, and
with reduction in fluid pressure, the earthquakes sharply decreased in frequency at the Rocky
Mountain Arsenal after injection of fluids stopped in 1966. The purpose of the Rangely oil field
seismicity experiment was to see if earthquake control and prevention of inadvertent triggering
of earthquakes might become feasible. (Raleigh, Healy, Bredehoeft, 1976)
The field experiment was designed to 1) know the fluid pressure in the vicinity of the hypocenter
of the earthquakes, 2) measure the absolute state of stress, 3) have precise hypocentral
locations and focal plane solutions for the earthquakes, and most important 4) to be confident
4690 Table Mountain Drive, Suite 200 TEL 303.237.2072
Golden, CO 80403 FAX 303.237.2659 www.oaconsulting.com
that the active phase of the experiment would not materially increase the likelihood of a
damaging earthquake. The area was also sparsely populated. The Chevron Rangely Oil Field
met these criteria, and an array of seismographs at Vernal, Utah had been recording small
earthquakes from the vicinity of Rangely since their installation in 1962. Chevron had been
waterflooding, the injection of water at high pressure for secondary recovery of oil, since 1957.
In the fall of 1967, a portable array of seismographs was installed and recorded 40 small
earthquakes in two areas within the oil field where fluid pressures were high due to
waterflooding. In 1968 Chevron Oil Company leaseholders and the operator, agreed to permit
the experiment to control seismic activity and the experiment began in September 1969 with
Chevron's cooperation. After a year of recording seismic activity with the local network of
seismographs, the fluid pressure in the vicinity of the earthquakes was reduced by back flowing
water from the injection wells. If the reduction of fluid pressure resulted in reduced seismic
activity, the pressure was raised again by injection and the cycle was repeated. Concurrent
measurements of reservoir pressure in nearby oil wells were used to establish the reservoir
performance and predict spatial distribution of pressure with the cycles of injection and
withdrawal. Measuring stresses in situ and the frictional properties of the reservoir rock, a test of
the effective stress hypothesis was made by comparing the observations with the predicted fluid
pressure for triggering earthquakes. (Raleigh, Healy, Bredehoeft, 1976)
There is little evidence of faulting in the Rangely area. At the western end of the oil field,
drainage patterns are aligned along a structure trending 30 degrees east of north that produced
500 meters (1,640 feet) of apparent displacement in rocks five kilometers north of the oil field.
There was no evidence of displacement along this fault where its projection to the south
intersected the rocks along the south flank of the doubly plunging anticlinal fold that is the
structural trap for the oil field. (Raleigh, Healy, Bredehoeft, 1976)
Several current investigations are underway to explore a potential link between seismicity to
operation of a few of the nation's approximately 30,000 Class II UIC wells used by the natural
gas and oil industry to dispose of produced water or to enhance resource recovery. These Class
II injection wells are a subset of more than 800,000 injection wells nationwide that handle a
variety of industrial wastes and the development of various minerals and geothermal energy
sources (API, 2012).
Underground Injection Control Regulation
The U.S. Environmental Protection Agency (EPA) regulates the UIC program and the injection
of fluids related to oil and gas production as Class II disposal wells for the protection of
underground sources of drinking water (USDWs). In many cases, the EPA delegated authority
to implement the UIC program to the states, with 39 states having primary authority over 95
percent of all UIC Class II wells. The EPA delegated primacy for regulation of Class II UIC wells
to the State of Colorado in April 1984. Class II UIC wells inject fluids associated with oil and
natural gas production. Most of the injected fluid is salt water, or brine, naturally present in the
formation, produced along with the oil and gas and is injected into a deep disposal well into a
formation that contains brine with similar or more saline water quality characteristics.
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Underground Injection Control and Seismicity in Colorado
The Colorado Oil and Gas Conservation Commission (COGCC) is the agency in Colorado with
primacy for permitting Class II UIC wells associated with oil and gas production operations. The
COGCC regulates operators of Class II UIC wells in accordance with federal law and COGCC's
rules and policies which are in place to reduce the likelihood of induced seismicity. The current
safeguards defined by the COGCC permit process include limits on injection volume at
pressures below the fracture gradient. The permit process also involves input from the Colorado
Division of Water Resources (CDWR), the Colorado Geological Survey (CGS), the Colorado
Department of Public Health and Environment (CDPHE), and EPA Region 8 UIC program in
Denver.
The COGCC requires Class II UIC wells be properly constructed with cemented surface casing
and production casing to isolate and prevent fluid flow between the injection zones and USDWs.
The COGCC UIC engineer reviews all relevant information including hydrogeologic studies,
CDWR water well information, COGCC geophysical well logs from area production wells. The
COGCC UIC engineer also reviews information on the specific formation and well construction
data submitted by the operator, including resistivity, cement bond, and geophysical logs to verify
that 1) the surface casing is set below the fresh water zones used as a water supply, and 2)
production casing and cement placement and quality adequately isolate the injection zone and
USDWs including fresh water zones that are not currently used as water supplies. The COGCC
requires mechanical integrity tests (MIT) be performed on the injection wells every five years.
The maximum surface injection pressure is calculated based on a default fracture pressure
gradient of 0.6 pounds per square inch (psi) per foot of depth. The operator may conduct a
State Rate Injection Test to define whether a higher injection zone fracture gradient exists. The
COGCC UIC engineer designates a maximum surface injection pressure as a condition of
permit approval. It is the COGCC's policy to keep injection pressures below the fracture
gradient, which is defined for each injection well, in order to minimize the potential for seismic
events related to fluid injection.
Mitigation and Minimization of Injection -Induced Seismicity
Injection -induced seismic events have the potential to impact USDWs. The EPA's UIC program
has undertaken investigation of a number of recent small to moderate magnitude seismic events
recorded in areas with Class II disposal wells related to unconventional hydrocarbon production.
The EPA's Office of Ground Water and Drinking Water (OGWDW) Drinking Water Protection
Division requested that the UIC national Technical Workgroup (NTW) develop
recommendations for consideration by UIC regulators. The UIC NTW consists of UIC staff from
each EPA regional office, EPA headquarters, and six state UIC program representatives. In
June 2011, a subgroup was formed to develop a report of recommending possible strategies for
managing or minimizing significant seismic events associated with induced seismicity in the
context of Class II disposal well operations.
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Unconventional production activities and larger volumes of waste water have created a need for
increased disposal capacity, and the permitting of new disposal wells to handle large volumes of
produced water and other exploration and production related waste water. Of the 30,000 Class
II UIC disposal wells, very few have produced seismic events with magnitudes greater than
M4.0. In addition, the EPA is unaware of any USDW contamination resulting from seismic
events related to injection -induced seismicity (UIC-NTW, 2014).
The NTW identified three key components that are thought to contribute to injection -induced
seismicity: 1) the presence of a stressed fault, 2) pressure buildup from disposal operations, and
3) a pathway for the increased pressure to communicate from the disposal well to the fault. The
NTW used a strategy that summarized geoscience factors and applications, applied petroleum
engineering methods, compiled and reviewed historic and current scientific literature from
ongoing projects and materials associated with injection -induced seismicity, and selected case
examples of Class II brine disposal wells suspected of inducing seismicity in different areas of
the country.
According to the NTW report, a fault of concern is a fault optimally oriented for movement and
located in a critically stressed region. The fault is also of sufficient size, possesses sufficient
accumulated stress/strain, such that fault slip and movement has the potential to cause a
significant earthquake. A fault may consist of a single fault or a fault zone comprised of multiple
faults and fractures.
Structural Geology
The Battlement Mesa PUD BMC A Pad UIC well site is located in an area on the southern
margin of the Piceance Basin. The Piceance Basin is a broad structural and depositional basin
trending northwest, that formed during Late Cretaceous time. The sedimentary rocks gently dip
between two degrees to five degrees (2° to 5°) northward into the center of the basin. The
surface geology of the site area consists of unconsolidated Quaternary age deposits. These
deposits are typically several tens of feet thick, and total thickness may be as much as 150 feet
thick. These unconsolidated sediments obscure fractures and faults in the bedrock in the area;
however, no there are no known major faults mapped in the area of the site.
Regionally within the Piceance Basin there are faults that trend to the northwest. There are
several northwest -trending faults present on the north side of Plateau Creek to the south of
Battlement Mesa and north of the Grand Mesa. These faults cut rocks as young as the upper
Wasatch and possess throws of less than 150 feet. Small recent fractures in the basalt capping
Grand Mesa are a result of landslide activity and do not extend far below the base of the basalt
(Yeend, 1969).
Recent seismic data for the area near Rifle suggests that monoclines, such as the Grand
Hogback, and similar monoclines in the Rocky Mountain foreland near the boundary with the
Colorado Plateau, overlie a west-, southwest-, or south -directed thrust system. The Grand
Hogback is interpreted as having formed above the tip of a Precambrian basement rock wedge
blind thrust fault that moved southwest and west-southwest into the Piceance Basin. The Divide
Creek Anticline and the Wolf Creek Anticline, located to the west of the Grand Hogback, are
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thought to be related to this same thrust system (Grout and Verbeek, 1992). These faults were
active when the Colorado Plateau and Rocky Mountains were being uplifted during the
Laramide orogeny during the late Cretaceous period.
Northwestward -trending faults with displacements large enough to be shown on areal geologic
maps are not common in the area; none have displacements exceeding 150 feet, and none
were traced for more than a mile. The faults of this set are uniform in strike direction, but some
appear to have had complex zones of movement and jointing rather than simple displacement
(Fischer, 1960).
The largest fault in the Rifle area, trends slightly north of west, nearly parallel to regional strike.
The strike refers to the attitude or position of linear features such as faults, outcrops, beds,
joints, and folds. In this case the regional strike is controlled by the structural orientation of the
Piceance Basin. The maximum displacement along this fault is about 500 feet observed in the
southern part of Section 34, Township 4 South, Range 92 West, and was mapped for about six
miles in the area (Fischer, 1960).
As many as 30 faults are described in the area of the Grand Hogback west of Glenwood
Springs. These faults consist of a series of parallel, northwest trending, west dipping, normal
faults that have broken the basalt cap and basalt gravels. The offset Quaternary basalt gravels
indicate possible recent movement, but due to the nature of deformation, large earthquakes
caused by the process would seem unlikely (Kirkham and Rogers, 1978).
The structural geology of the Roan Plateau area to the north of the site and on the southwestern
flank of the Piceance Basin is fairly simple. The deepest part of the basin is about 18,000 feet
below sea level and lies about 18 miles to the north of the Roan Plateau. The depth to the
Precambrian basement within the area increases from about 7,500 feet below sea level at the
southwestern corner of the area to about 14,000 feet below sea level along the northern
boundary of the area (Hail, 1992).
There are no major faults in the central Roan Plateau area. Three narrow grabens are present
along a northwest -trending fracture zone to the north of the Crystal Creek anticline in the central
part of Township 4 South, Range 96 West, and Township 4 South, Range 97 West. Maximum
measured stratigraphic displacements on these faults do not exceed 120 feet; most are
considerably less. These grabens are thought to lie along a single fracture zone that extends for
a total distance of about 9 miles (Hail, 1992).
Colorado Geological Survey Earthquake and Late Cenozoic Fault Map
According to the Colorado Geologic Survey most people are surprised to learn that natural
earthquakes do occur in Colorado. The largest known earthquake Colorado experienced was a
magnitude 6.6 earthquake in November 1882 in north -central Colorado. (Blume and Sheehan,
2003). Natural earthquakes can be triggered by movements along faults, by rock fall, or
subsidence resulting from the collapse of underground mines. Uplift of the Colorado Rocky
Mountains and Colorado Plateau, and the creation of the Piceance Basin, occurred as a result
of tectonic activity and movement along faults during the Late Cretaceous and early Tertiary
geologic periods
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The only seismic event shown on the Colorado Geologic Survey Earthquake and Late Cenozoic
Fault and Fold Map Server in close proximity to the site is related to the Atomic Energy
Commission's Project Rulison in September 1969. Project Rulison was an induced seismic
event resulting from the detonation of an underground nuclear device to stimulate natural gas
production from tight sands at a depth of 8,426 feet. It had a magnitude of 5.3 on the Richter
scale.
Another underground nuclear detonation induced seismic event took place at the Rio Blanco
test site in Rio Blanco County northwest of Rifle, Colorado in May 1973. The Rio Blanco test
involved simultaneous detonation of three 33 -kiloton nuclear devices and was also designed to
stimulate natural gas production from tight gas sands. The event had a magnitude of 5.4 on the
Richter scale
National Seismic Hazard Maps
The 2014 USGS National Seismic Hazard Map Long-term Models display earthquake ground
motions for various probability levels across the United States. The maps show the Parachute —
Battlement Mesa area as having 0.03 to 0.05 peak ground acceleration, expressed as a fraction
of standard gravity (g), with a ten -percent probability of exceedance in 50 years. Maps prepared
by the USGS and the Colorado Geologic Survey do not show any Quaternary faults in the
Parachute — Battlement Mesa area. The Piceance Basin is shown in an area with < 1c/0 chance
of damage.
The 2016 and 2017 USGS National Seismic Hazard Map short-term models indicated high
seismic hazard (greater than 1°/0 probability of potentially damaging ground shaking in one-year
in Oklahoma - Kansas, Raton Basin along the Colorado -New Mexico border, north Texas, north
Arkansas, and the New Madrid seismic zone. During 2016, several damaging induced
earthquakes occurred in Oklahoma within the highest hazard region of the 2016 forecast. All of
the 21 magnitude (M) >_ 4 and three M >_ 5 earthquakes occurred within the highest hazard area
in the 2016 forecast. Serval observations of damaging ground shaking were also recorded in the
highest hazard area of Oklahoma. Outside the Oklahoma -Kansas focus area, two earthquakes
with M >_ 4 occurred near Trinidad, Colorado, but no earthquakes with M > 2.7 were observed in
north Texas or the north Arkansas focus areas (Peterson et al, 2016).
The 2017 forecasted seismic rates are lower in regions of induced activity due to lower rates of
earthquakes in 2016 as compared to 2015, which may be related to decreased wastewater
injection, caused by regulatory actions or by a decrease in unconventional oil and gas
production, or both. The 2017 forecasted hazard is still significantly elevated in Oklahoma as
compared to the hazard calculated from seismicity before 2009 (Peterson et al, 2016).
Garfield County Earthquakes
Olsson reviewed published resources for earthquake potential in Colorado (Kirkham and
Rogers, 1978) and felt reports for select Colorado earthquakes (Oaks and Kirkham, 1986). A
series of earthquakes occurred in the late 1970s to mid-1980s to the west of Mount Sopris. The
earthquakes had magnitudes of 3.0 to 4.0, at depths of approximately 5 kilometers (3.11 miles).
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A 4.3 magnitude earthquake occurred to the north near County Road 163 and west of Highway
82 south of Glenwood Springs on January 7, 1971. This earthquake was reportedly at a depth
of 33 kilometers, or approximately 20.51 miles.
Two 2.9 magnitude quakes occurred near Douglas Pass including one on March 8, 1994, and
another 2.9 magnitude earthquake that occurred on March 19, 2002. These earthquakes appear
to be the result of natural causes and are not related to injection of fluids.
A 2.5 magnitude earthquake was recorded on July 9, 2009 near Palisade in Mesa County. An
earthquake occurred north of Grand Junction on January 30, 1975 and had a magnitude of 4.4
on the Richter scale and was felt as far away as the towns of DeBeque and Delta.
Earthquakes have been recorded in eastern Garfield County. The area of New Castle has
experienced earthquakes with one reported on December 21, 1906, and two recorded in late
December 1920. These are taken from newspaper accounts at the time and are described as
'felt reports' meaning that they were taken from personal accounts at the time. These
earthquakes were assigned an intensity of III and V, respectively, on the Mercalli scale based
on the described damage (Oaks and Kirkham, 1986).
More recently earthquakes have been recorded in the New Castle area including two in October
1990 with magnitude of 2.1 and 2.3 on the Richter scale, and another on December 12, 1990
with a magnitude of 2.7 on the Richter scale. A 4.3 magnitude earthquake occurred near
Glenwood Springs in January 1971; a 2.2 magnitude earthquake occurred north of Glenwood
Springs on August 10, 2001; and another 3.8 magnitude earthquake occurred five miles west of
Glenwood Springs on February 8, 2006.
Residents of Silt and New Castle felt a 3.3 magnitude earthquake on January 30, 2017 that was
centered 5 kilometers south of New Castle. The earthquake was reportedly the largest to hit the
area in the past 10 years, but was the third earthquake recorded since October 2016. A swarm
of 11 earthquakes occurred near the Marble area that ranged from magnitude 1.1 to 2.8 on the
Richter scale. A 2.9 magnitude earthquake occurred near New Castle on Christmas Day 2016.
According to a January 31, 2017 Denver Post article and January 30, 2017 Post Independent
article, Ms. Julie Dutton, a geophysicist with the National Earthquake Information Center, said
that she doubted any connection with oil and gas operations and high-volume injection wells
used for disposal of produced water and fracking fluids. "There are so few earthquakes there, it
is difficult to make any kind of correlation," she said. "It's not something that we think is
becoming more active. The area will and does have infrequent earthquakes."
Summary
Colorado is well known in earthquake literature for the discovery in the late 1960s of induced
seismicity resulting from the injection of wastewater at the Army's Rocky Mountain Arsenal
facility. A 1969 experiment performed in the Rangely oilfield waterflood areas, showed induced
seismicity events could be controlled, and if triggered inadvertently, future earthquakes could be
prevented by reducing fluid pressure. The experiment at Rangely confirmed the hypothesis that
earthquakes could be triggered by an increase of fluid pressure, and the cessation of seismic
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activity within one day of the initiation of back flowing established the correlation between fluid
pressure and earthquakes beyond reasonable doubt. There is a strong correlation between the
frequency of the seismic activity and variation in the fluid pressure around the predicted values
of effective stress. The frictional strength of the fault varies in direct proportion to the difference
between the total normal stress and the fluid pressure.
Extraction of oil and injected water just to the north of the experimental wells in Rangely served
to maintain fluid pressures over most of the fault zone well below the critical value for triggering
earthquakes. The Rangely experiment confirmed what was known through laboratory testing on
a much larger and more complex scale. The results suggest that earthquakes triggered
inadvertently by raising subsurface fluid pressures in an otherwise seismically inactive area can
be controlled. Adherence to permit limits placed on the volumes and pressures under which
wastewater injection occurs prevents triggering inadvertent induced seismic events.
The COGCC and EPA have safe guards in place to prevent injection induced seismic events
from occurring. The Class II UIC well must be constructed to prevent communication between
the disposal zone and overlying fresh water zones. The Class II UIC well must pass a
mechanical integrity test and must be re -tested every five years. The injected volumes and
maximum surface pressures recorded in the permit are designed to be below the fracture
pressure gradient.
There are no mapped or known major faults in the area. Most of the northwest trending fault
traces that have been mapped in the region show limited displacement of 150 feet and are not
laterally extensive. There are relatively few recorded earthquakes in the area of the site, as
shown on the Colorado Geologic Survey Earthquake and Fault Map server. The closest
seismicity events are related to the detonation of subsurface nuclear devices in the late 1960s
and early 1970s.
The sedimentary rock in the formation used for disposal would have to be isolated from shallow
fresh water supplies and demonstration of this is required in the permitting process. For injection
induced -seismicity to occur, there would have to be a connection from the injection zone
formation to a stressed fault.
OLSSON ASSOCIATES
.---p/awai d
James W. Hix
Senior Geologist
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References
API Document, 2012, Injection Wells & Induced Seismicity, 2 p.
Blume F., and Sheehan, A.F., 2003, Quantifying Seismic Hazard in the Southern Rocky
Mountains through GPS Measurements of Crustal Deformation, University of Colorado, Boulder,
Department of Geological Sciences, 9 p.
Fischer, R.P., 1960, Vanadium -Uranium Deposits of the Rifle Creek Area, Garfield County,
Colorado, USGS Bulletin 1101, 52 p. and 4 plates
Grout M.A., and Verbeek, E.R., 1992, Fracture History of the Divide Creek and Wolf Creek
Anticlines and Its Relation to Laramide Basin -Margin Tectonism, Southern Piceance Basin,
Northwestern, Colorado, USGS Bulletin 1787, Z32 p.
Hail, W.J., Jr., 1992, Geology of the Central Roan Plateau Area, Northwestern Colorado, USGS
Bulletin 1787, R24 p., 2 plates, 8 figures
Kirkham, R.M. and Rogers, W.P., 1978, Earthquake Potential in Colorado, a Preliminary
Evaluation, Colorado Geological Survey Open File Report 78-3, 211 p.
McClain, W.C., 1970, On Earthquakes Induced by Underground Fluid Injection, Oak Ridge
National Laboratory, Union Carbide Corporation for the U.S. Atomic Energy Commission, 22 p.
Oaks S.D., and Kirkham, R.M., 1986, Results of a Search for Felt Reports for Selected
Colorado Earthquakes, Colorado Geological Survey, Information Series 23, 89 p.
Petersen, et al, 2016, 2016 One -Year Seismic Hazard Forecast for the Central and Eastern
United States from Induced and Natural Earthquakes, USGS OFR 2016-1035, 52 p.
http://dx.doi.org/10.3133/ofr20161035
Raleigh, C.B., Healy, J.H., Bredehoeft, J.D., 1976, An Experiment in Earthquake Control at
Rangely, Colorado, Science, New York, NY, Vol. 191, 1230 — 1237 p.
Yeend, W.E., 1969, Quaternary Geology of the Grand and Battlement Mesas Area, Colorado,
USGS Professional Paper 617, 50 p. and 1 plate
COGCC, January 19, 2011, COGCC Underground Injection Control and Seismicity in Colorado,
5 p.
U.S. EPA Underground Injection Control National Technical Working Group, (UIC-NTW)
Revised November 12, 2014, Minimizing and Managing Potential Impacts of Injection -Induced
Seismicity from Class II Disposal Wells: Practical Approaches, 415 p.
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References (Continued) - Internet Websites
Colorado Geological Survey
http://coloradogeologicalsurvey.org/geologic-hazards/earthquakes-2/
USGS Earthquake Hazards Program
http://earthquake.usgs.gov/hazards/products/conterminous/index.php#2014
U.S. EPA — Underground Injection Control National Technical Workgroup
https://www.epa.gov/uic/underground-injection-control-national-technical-workgroup
Denver Post Article — January 31, 2017 Garfield County's Biggest Earthquake in Decade Hits
Silt
http://www.denverpost.com/2017/01 /31 /garfield-county-earthquake-silt/
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