HomeMy WebLinkAbout1.11 Geohazards Rpt
Article 4-203.G.4
Geologic and Soils Hazard
Report
Ursa Operating Company LLC
Tompkins Injection Well
OA Project No. 014-2878
NATURAL AND GEOLOGIC HAZARDS
ASSESSMENT REPORT
URSA OPERATING COMPANY
TOMPKINS UIC – COUNTY ROAD 309
SE ¼, SE ¼, SECTION 5, T7S, R95W, 6TH P.M.
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
JANUARY 2016
PROJECT NO. 014-2878
Geologic Hazard Report i Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
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 16, 2013. According to Section 7-108
Use of Land Subject to Natural Hazards of the Garfield County LUDC “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 requires a Natural and Geologic Hazard Study be prepared by a qualified
professional geologist and submitted with a development plan or plat. 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.”
The LUDC defines a Hazard Area as “An area that contains or is directly affected by a geologic
hazard, including but not limited to the following types of areas.”
A. Avalanche Area. “A mass of snow or ice and other material that may become
incorporated therein as such mass moves rapidly down a slope.”
B. Landslide Area. “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.”
C. Mudflow Debris Area. “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.”
D. Radioactive Area. “An area subject to various types of radiation emission from
radioactive minerals that occur in natural or manmade deposits of rock, soil, or
water.”
E. Potentially Unstable Soils. “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.”
According to the Garfield County LUDC Section 4-203 Description of Submittal Requirements,
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.”
Geologic Hazard Report ii Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
Currently, the State of Colorado does not require licensure or registration of geologists;
however, Colorado Revised Statutes do require that geologic reports be prepared or authorized
by a professional geologist, and the term “Professional Geologist” is defined in Colorado
Statutes.
The references for these Statutes are shown here:
34-1-201. Definitions. As used in this part 2, unless the context otherwise requires:
(1) “Geologist” means a person engaged in the practice of geology.
(2) “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.
(3) “Professional geologist” is a person 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 additional five years of geological
experience to include no more than two years of graduate work.
(4) 34-1-202. Reports containing geologic information. Any report required by law or by
rule and regulation, and prepared as a result of or based on a geologic study or on
geologic data, or which contains information relating to geology, as defined in Section
34-1-201 (2), and which is to be presented 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 as defined in Section 34-1-201(3).
Geologic Hazard Report iv Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
TABLE OF CONTENTS
Natural and Geologic Hazard Report Preface ............................................................................... i
Professional Geologist Certification ............................................................................................. iii
TABLE OF CONTENTS ............................................................................................................... iv
FIGURES ..................................................................................................................................... iv
1.0 EXECUTIVE SUMMARY ..................................................................................................... 1
2.0 GENERAL SITE LOCATION AND BACKGROUND ............................................................ 3
2.1 Project and Site Description ............................................................................................ 3
2.2 Structural Geology ........................................................................................................... 3
2.4 Site Geology .................................................................................................................... 4
2.5 Soil ................................................................................................................................... 4
2.6 Hydrologic Setting ............................................................................................................ 5
2.7 Aquifers ............................................................................................................................ 5
3.0 NATURAL AND GEOLOGIC HAZARD ASSESSMENT ...................................................... 6
3.1 Utilities ............................................................................................................................. 6
3.2 Avalanche Hazard Area ................................................................................................... 6
3.3 Landslide Areas or Potential Landslide Hazard Areas .................................................... 6
3.4 Rockfall Areas .................................................................................................................. 7
3.5 Alluvial Fan Hazard Areas ............................................................................................... 7
3.6 Unstable or Potentially Unstable Slopes .......................................................................... 7
3.7 Corrosive or Expansive Soils and Rock ........................................................................... 7
3.8 Mudflow and Debris Fan Areas ....................................................................................... 8
3.9 Development Over Faults and Risk of Seismic Activity ................................................... 8
3.10 Injection Wells and Induced Seismicity .......................................................................... 10
3.11 Underground Injection Control Regulation ..................................................................... 10
3.12 Underground Injection Control and Seismicity in Colorado ........................................... 11
3.13 Mitigation and Minimization of Injection-Induced Seismicity .......................................... 11
3.14 Flood Prone Areas ......................................................................................................... 12
3.15 Collapsible Soils ............................................................................................................ 12
3.16 Mining Activity ................................................................................................................ 12
3.17 Radioactivity .................................................................................................................. 13
4.0 Conclusions and Recommendations .................................................................................. 14
5.0 References ......................................................................................................................... 15
FIGURES
List of Figures
SL-1 Site Location Map
G-1 Geology Map
NRCS Soils Map
Hydrology Map
FP-1 Floodplain Map
Geologic Hazard Report 1 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
1.0 EXECUTIVE SUMMARY
Olsson Associates (Olsson) was contracted by Ursa Operating Company to assess natural and
geologic hazards potentially present in the area of the proposed Tompkins underground
injection control (UIC) well pad located in the SE ¼ SE ¼ Section 5, Township 7 South, Range
95 West, of the 6th Principal Meridian, Garfield County, Colorado. The site is at an elevation of
approximately 5,525 feet above mean sea level (amsl) as shown on the attached SL-1
Tompkins UIC Site 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 LUDC. 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 Rock-fall 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; and
I. Development Over Faults.
Ursa Operating Company requested that Olsson use the soils maps and hydrology map
prepared by HRL Compliance Solutions of Grand Junction, Colorado. Olsson did not prepare
these maps and is not responsible for their content.
This report presents Olsson’s findings following an evaluation of these and other geologic
hazards potentially affecting the site and proposed development. The Ursa Operating Company
site was found to be suitable for the proposed development with consideration of the following
identified geologic hazards.
Development in areas characterized by the Potts-Ildefonso, soil unit #58, are limited by
steep slopes, and the Ildefonso soils have large stones. These limitations may be
mitigated by proper engineering and design.
The Potts-Ildefonso soils are corrosive to unprotected steel but the risk of corrosion to
concrete is low. Corrosion can be mitigated by coating the steel or by cathodic
protection.
The erosion hazard for the Potts-Ildefonso complex (Unit #58) is listed as moderate.
According to the Preliminary Geologic Map of the Grand Valley Quadrangle, Garfield
County (1:24,000), the proposed site is located on Quaternary age (Holocene) alluvial
terrace and fan gravel deposits.
Geologic Hazard Report 2 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
According to the Geologic and Structural Map of the Grand Junction Quadrangle,
Colorado and Utah (1:250,000), the site bedrock is the Tertiary age Wasatch Formation,
but does not show the overlying Quaternary unconsolidated deposits. The adjoining
Leadville Quadrangle Map (1:250,000) shows the area covered by landslide deposits, as
does the geologic mapping at a scale of 1:500,000 on the Colorado Oil and Gas
Conservation Commission (COGCC) GIS database website.
The site is not mapped within the FEMA 100-year flood plain. The site is located at an
elevation of approximately 5,525 feet, approximately one half mile south of the Colorado
River. It is about 1,000 feet southwest of Battlement Creek, 150 feet east-northeast of an
unnamed intermittent drainage, and 160 feet west - southwest of an unnamed
intermittent drainage. These drainages may experience flash floods, but are not
expected to carry the volume of flow that the main tributary drainages carry.
The Tompkins UIC can be constructed to compensate for these limitations and potential
hazards. This report should be read in its entirety, including but not limited to the conclusions
and recommendations in Section 4.0.
Geologic Hazard Report 3 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
2.0 GENERAL SITE LOCATION AND BACKGROUND
Ursa Operating Company LLC (Ursa) contracted Olsson Associates (Olsson) to conduct a
natural and geologic hazards assessment as part of the proposed development of the Tompkins
UIC well pad. The proposed facility will be used as a UIC class II disposal well for exploration
and production wastes. The following sections provide information about the proposed
development and the site geologic setting. The site surface and bedrock geology is shown on
the G-1 Geology Map.
2.1 Project and Site Description
The proposed Tompkins UIC well pad is located to the northeast of the town of Parachute,
Colorado off of County Road 300. The site is located in the SE ¼ SE ¼ Section 5, T7S, R95W,
6th P.M. and is located in parcel # 240705400085. The surface land is owned by Thomas
Tompkins. The site is located north of the intersection of Morrisania Mesa Road (County Road
301) and County Road 309, to the northeast of the community of Battlement Mesa.
2.2 Structural Geology
The Tompkins UIC well pad site is 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.
The site is located near the edge of the Geologic and Structure Map of the Grand Junction
Quadrangle and the Leadville Quadrangle maps (Scale 1:250,000). There are no mapped faults
shown in the area of the site 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) (Scale
1:24,000).
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 mapped in the area of the site.
Geologic Hazard Report 4 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
2.3 Earthquake and Fault Mapping
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. 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. Faults can be
difficult to map at the surface due to the bedrock being covered by unconsolidated materials. A
discussion of the regional earthquake history is included in Section 3.9. Earthquakes can also
be induced by human activities as discussed in Section 3.10.
2.4 Site Geology
According to the Preliminary Geologic Map of the Grand Valley Quadrangle (Donnell, Yeend,
Smith, 1986), bedrock mapped to the east of the project area consists of the Eocene and
Paleocene-age Shire Member of the Wasatch Formation which consists of purple, lavender,
gray, and brown claystone, with minor beds of fine- to medium-grained sandstone. The
maximum exposed thickness of the Wasatch is approximately 1,200 feet.
The bedrock in the area of the site is covered with unconsolidated sediments of Quaternary age
consisting of alluvial terrace and fan gravel deposits consisting of grayish brown sandy gravel of
basalt and locally derived slabby siltstone, marlstone, and sandstone. These units are
moderately to poorly sorted (well graded), poorly stratified, and contain rock fragments that are
angular to well-rounded depending on the distance the material was transported. These
deposits have a maximum thickness of 200 feet.
Weak claystone in the upper Wasatch Formation is responsible for the slope failure which
resulted in slides and debris flows during a time when the climate was much wetter. These
alluvial terrace and fan gravel deposits were reworked and derived from landslide deposits from
higher elevations up on Battlement Mesa.
2.5 Soil
The Natural Resources Conservation Service (NRCS) Soils Map shows the area soil types.
Soils, consisting of the following units, are within the study area around the Tompkins UIC well
pad:
Potts-Ildefonso complex, 12% to 25% slopes, Map Symbol 58: The Potts-Ildefonso
complex soil is a deep, well drained, sloping soil formed on fans and high terraces at
elevations between 5,100 feet and 6,200 feet above mean sea level. Typically the
surface layer is a moderately alkaline, pale brown loam about three inches thick and the
substratum is light brown to brown silty clay loam to a depth of 60 inches. Permeability is
very slow, and available water capacity is high. Surface runoff is moderately rapid, and
the erosion hazard for the Potts Ildefonso complex soils is moderate.
Slope is listed as a limitation for development on both the Potts and Ildefonso soils and large
stones occur in the Ildefonso soil.
Geologic Hazard Report 5 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
The Potts-Ildefonso soils in the vicinity of the site are corrosive to unprotected steel but the risk
of corrosion to concrete is low. Buried piping and structures onsite will need to be coated or
have adequate cathodic protection to prevent corrosion.
2.6 Hydrologic Setting
The site is located at an elevation of approximately 5,525 feet on a terrace above the Colorado
River flood plain. The Colorado River is located approximately half a mile to the northwest at an
elevation of approximately 5,082 feet to 5,200 feet amsl. The Battlement Creek drainage is
located approximately three-quarters of a mile to the northeast. There are unnamed intermittent
drainages located approximately 150 feet to the west-southwest and another 160 feet east-
northeast of the site. These surface water features are shown on the Hydrology Map.
2.7 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 small hydraulic conductivity in the rock matrix.
Sandstone and siltstone generally occur in lenticular bodies and locally have moderate hydraulic
conductivities which range from 0.001 to 0.01 foot 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 80 feet to 300 feet below ground surface in
the vicinity of the site. A water well permitted (Permit # 67379F) to Thomas L. Tompkins for
domestic use has a total depth of 178 feet and a static water level reported at 147 feet below
ground surface (bgs).
Groundwater within the unconsolidated sediments in the area of the proposed site 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 site 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 site.
Springs used to augment the Parachute community water supply are located approximately
2,000 feet to the north of the proposed Tompkins UIC well. Ursa received a watershed permit
and approval from the Town of Parachute for the Tompkins UIC well location in September
2014.
Geologic Hazard Report 6 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
3.0 NATURAL AND GEOLOGIC HAZARD ASSESSMENT
The following sections present the assessment of geologic hazards in the vicinity of the
proposed injection well. The SL-1 Site Location Map shows the location of the Tompkins UIC
well pad site in relation to the affected parcel 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. 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 flooding, above-ground
utilities, such as transformers, are not expected to be affected by geologic or other natural
hazards.
Trenches for water pipelines, natural gas pipelines, and electrical lines are expected to be
associated with the proposed development. The slopes and corrosive soil 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.
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 site.
Avalanches are not expected to affect the proposed UIC well site, since it is located at an
elevation of approximately 5,160 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).
3.3 Landslide Areas or Potential Landslide Hazard Areas
The site is located on alluvial terrace and fan gravel deposits. Larger scale maps describe these
deposits as landslide deposits (Ql) (Yeend, 1969). These alluvial terrace and fan gravel deposits
are derived from and reworked from landslide deposits further up on Battlement Mesa and were
transported down onto the Colorado River flood plain at the end of the last ice age when the
climate was wetter (Yeend, 1969). Solifluction deposits are extensive in the Rulison 7.5-minute
Geologic Hazard Report 7 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
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 the Garfield County Map 24 – Surface Geology map, Geologic Hazards
Identification Study (Lincoln Devore, 1975-1976), landslides are not shown to the south of
Interstate 70 in the Parachute – Battlement Mesa area as this area was not mapped. Landslide
areas are shown to the northwest of the town of Parachute (Garfield County, Surface Geology,
2007).
3.4 Rockfall Areas
The site is not located within an area that has been mapped as having rockfall or potential for
rockfall. Potential rockfall areas are present along the steep drainages incised by the major
drainages and at higher elevations on Battlement Mesa.
3.5 Alluvial Fan Hazard Areas
The site is located in an area that is not mapped as being in an alluvial fan hazard area
according to the Garfield County Surficial Geology, 2007. The site is located on alluvial terrace
and fan gravel deposits (Symbol Qla) according to the Preliminary Geologic Map of the Grand
Valley Quadrangle (Donnell, Yeend, Smith, 1986). The site is on the northeastern part of
coalescing alluvial fans created along the north flank of Battlement Mesa by Battlement Creek,
Monument Gulch, and other unnamed intermittent drainages. These deposits lie about 200 feet
above the Colorado River flood plain.
3.6 Unstable or Potentially Unstable Slopes
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 site as being identified in a slope hazard 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 Potts-Ildefonso complex soils are found on 12% to 25% slopes, and slope is listed as a
severe limitation for development on these soils. Engineering, design, and construction
practices of the proposed development are expected to mitigate the limitation of slopes at the
site, since the site is located within an area developed for other land uses, including
development of natural gas well pads. The site may require mitigation for slope and will be
graded and constructed for this purpose.
3.7 Corrosive or Expansive Soils and Rock
According to the Soil Survey of the Rifle Area, the Potts-Ildefonso complex soils are listed as
highly corrosive to unprotected steel, but the potential risk to corrosion of concrete is listed as
Geologic Hazard Report 8 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
moderate to low. The corrosive hazard of these soils may be mitigated by coating the steel or by
providing adequate cathodic protection. Use of corrosion resistant concrete may be necessary
as a precaution.
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 as
compared to when they are dry. The 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 Potts-Ildefonso complex soils do not have a high shrink-swell potential and are not
considered expansive soils. There is not a potential for expansive rock or soils in the area of the
proposed Tompkins UIC site.
3.8 Mudflow and Debris Fan Areas
The site is not located in an area of mud flow and debris fan areas, but is characterized by
alluvial terrace and fan gravel deposits. These deposits are derived from and reworked from
Quaternary age landslide deposits deposited as coalescing alluvial fans along the north flank of
Battlement Mesa. Mudflow and fan gravel deposits, derived largely from solifluction deposits to
the east of the quadrangle, are mapped to the south of Section 5 in Section 8. These mudflows
originated 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. Glacial conditions
existed on the Grand Mesa during the Pleistocene age. Abundant annual runoff is 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).
3.9 Development Over Faults and Risk of Seismic Activity
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 site.
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).
Geologic Hazard Report 9 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
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.
The 2014 USGS National Seismic Hazard Maps 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.
Earthquakes have been recorded historically 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.
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. A minor
earthquake occurred in the northwestern part of Colorado on November 22, 1982 at 3:09 a.m.
MST. The magnitude 2.9 (Richter scale) earthquake was located about 18 miles northeast of
the town of Rifle and was felt at a fish hatchery in the area.
A swarm of earthquakes occurred in the Carbondale – Glenwood Springs area in the 1980s.
The largest earthquake 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. Of the hundreds of quakes
that occurred in the Carbondale area during that time period, 12 were reported as felt.
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.
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. 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. A 2.5 magnitude earthquake was recorded on July 9, 2009 near Palisade in
Mesa County.
The only seismic event shown on the Colorado Geologic Survey Earthquake and Late Cenozoic
Fault and Fold Map Server in close proximity to the Tompkins 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.
Geologic Hazard Report 10 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
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. The area of these tests was selected in part due to the lack of major faults.
3.10 Injection Wells and Induced Seismicity
Most earthquakes or seismic events occur as the result of natural geologic phenomena as
discussed in the previous sections. Seismic events that are triggered by injection of fluids into
the subsurface are known as induced seismicity which is defined as seismicity caused by
human activities, such as injecting waste water into deep underground injection control (UIC)
disposal wells, which results in a release of energy within the earth. Under certain
circumstances, the increased pore pressure resulting from fluid injection, whether for waste
disposal, secondary recovery of oil, geothermal energy, or solution mining, can trigger seismic
activity. The conditions that result in slippage on faults or fractures as a result of pore pressure
can be predicted through the Mohr-Coulomb failure criterion (Nicholson and Wesson, 1990).
One of the well-known and documented cases of induced seismicity occurred in the 1960s at
the Rocky Mountain Arsenal near Denver, Colorado. The U.S. Army disposed of waste fluids
from chemical manufacturing operations in a deep injection well through approximately 12,000
feet of sedimentary rock into relatively impermeable Precambrian crystalline basement rocks
(Healy et al, 1968). A series of small earthquakes occurred soon after injection began in 1962,
many of which were felt in the greater Denver area. A correlation was noticed in the frequency
of earthquakes and the volumes of fluid injected. Pumping ceased in 1966 due to the possible
hazards associated with the induced earthquakes. Fluid was inadvertently injected directly into a
major subsurface fault structure (Nicholson and Wesson, 1990).
Several 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 wastewater
sources (API, 2012).
3.11 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.
Geologic Hazard Report 11 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
3.12 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 Step
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.
3.13 Mitigation and Minimization of Injection-Induced Seismicity
Injection-induced seismic events have the potential to impact USDWs. The EPA’s UIC program
has undertaken an 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.
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
Geologic Hazard Report 12 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
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.
3.14 Flood Prone Areas
The facility is not shown within the FEMA 100 year flood hazard zone based on the Flood Plain
Map in the Vicinity of the Town of Parachute, Garfield County, Colorado, or a Firmette Map
generated from the FEMA data. The Colorado River flood plain is located approximately a half
mile to the north of the site at elevations that range 5,200 feet to 5,085 feet. The unnamed
drainage and the Monument Gulch drainage are shown as having Zone A – 100-year flood
plains located along their banks. These areas are also prone to flash floods. The flood plain
along the Colorado River is shown in relation to the Tompkins UIC well pad on the attached
Flood Plain Location Map.
3.15 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.
Collapsible soils have not been mapped in the area and are not expected to be encountered in
the vicinity of the site.
3.16 Mining Activity
A review of the Grand Valley 7.5-minute quadrangle and aerial photographs did not show any
significant mining activities in close proximity to the proposed Tompkins UIC well site. Oil shale
mining was conducted north of the Town of Parachute, and there are sand and gravel
operations along the Colorado River. There were no mining activities shown in the immediate
area of the site.
Geologic Hazard Report 13 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
3.17 Radioactivity
Naturally occurring radioactive materials are not expected to be an issue at the site. 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. A NORM survey including site specific testing
could be performed to further assess the radon potential at the site 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 site and are stratigraphically below the depth of the
Wasatch Formation.
The 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 site since the development
will not include any occupied structures, personnel will not be onsite for extended periods, and
the site will not be developed with structures containing basements or substructures in which
radon can accumulate.
Geologic Hazard Report 14 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
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 Tompkins UIC site located in Garfield
County, Colorado.
Avalanche conditions are not expected to be a hazard in the area of the site.
The site is located on alluvial terrace and fan gravels, derived from and re-worked from
landslide deposits, and overlying bedrock consisting of the Wasatch Formation. There
are existing gas wells and other structures in the area. The landslide, alluvial terrace,
and fan gravels are not expected to constitute a geologic hazard for the Tompkins UIC
site development.
Rockfall areas are not present in the area of the site and are not expected to be a
geologic hazard affecting the site.
The site is not in an area mapped as an alluvial fan hazard area; however, the site is
underlain by alluvium and fan gravels. The area has been mapped at large scale as
landslide deposits. These landslide deposits formed at the end of the last ice age when
the climate was wetter, and are not expected to pose a hazard to the proposed
Tompkins UIC well site.
Slope is listed as a limitation for the Potts-Ildefonso soils; however, it is expected that
with appropriate design and engineering controls the site can be developed for its
intended use. The soil erosion hazard for the Potts – Ildefonso complex soils (Unit #58)
is listed as moderate.
The Potts-Ildefonso complex soils are listed as highly corrosive to steel, but the potential
of corrosion to concrete is low. Corrosion can be mitigated by coating steel or by using
appropriate cathodic protection. Use of corrosion resistant concrete may be necessary.
The Potts-Ildefonso complex have a low shrink-swell potential. Expansive soils are not a
hazard at the Tompkins UIC site.
Collapsible soils are not present in the vicinity of the proposed Tompkins UIC site.
No significant faults have been mapped or are known in the Tompkins UIC site.
The site is not mapped as being within the 100-year flood plain. Flash flooding is a
hazard for lower elevations along Battlement Creek, Monument Gulch, and areas along
the Colorado River. There are unnamed drainages located approximately 150 feet to the
west-southwest and another located approximately 160 feet to the east-northeast;
however, it is expected that these drainages do not pose a significant flooding hazard.
There are no mining activities shown in the vicinity of the site. 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
site. 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 site.
Geologic Hazard Report 15 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
5.0 References
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.
Cashion, W.B., 1973, Geologic and Structure Map of the Grand Junction Quadrangle,
Colorado and Utah, USGS, Map I-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.
Fischer, R.P., 1960, Vanadium-Uranium Deposits of the Rifle Creek Area, Garfield
County, Colorado, U.S.G.S. Bulletin 1101, 52 p.
Hail, W.J., Jr., 1992, U.S.G.S. Bulletin 1787-R, Geology of the Central Roan Plateau Area,
Northwestern, Colorado, 26 p.,
Healy, J.H., Rubey, W.W., Griggs, D.T., Raleigh, C.B., 1968, The Denver Earthquakes
Disposal of Waste Fluids by Injection into a Deep Well Has Triggered Earthquakes near
Denver, Colorado, Science, 27 September 1968, Volume 161, Number 3848, 10 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)
Nicholson C., and Wesson R.L., 1990, Earthquake Hazard Associated with Deep Well
Injection – A Report to the U.S. Environmental Protection Agency, USGS Bulletin 1951,
86 p.
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.
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 Commission http://cogcc.state.co.us/
Natural Resources Conservation Service - Soil Survey http://www.nrcs.usda.gov/
Garfield County
Slope Hazards: http://garfield‐county.com/geographic‐information‐
systems/documents/6439291200422slopehaz.pdf
Geologic Hazard Report 16 Olsson Associates
Ursa Operating Company Tompkins UIC Golden, Colorado
Garfield County, CO January 2016
Soil Hazards: http://garfield‐county.com/geographic‐information‐
systems/documents/64335291200423soilhaz.pdf
Surficial Geology of Garfield County: http://garfield‐county.com/geographic‐
information‐systems/documents/geologic‐hazards/24surfgeo.pdf
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
FIGURES
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To mp kins Pad
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Cornell Ditch
DISCLAIMER : This Geographic Information System (GIS) and itscomponents are designed as a source of reference for answeringinquiries, for planning and for m odeling. G IS is not intended, nor does itreplace legal description inform ation in the chain of title and otherinformation contained in official governm ent records such as the CountyClerk and Recorders office or the courts. In addition, the representationsof locations in this GIS cannot be substituted for actual legal surveys.
Project Number: 014-2878
Drawn By: JWH
Revision Date: 1/14/2015
Site Loca tion Ma p Ursa O perating Compa nyTompkins PadGarfield Co unty, CO Se c 5, T7S, R 95W, 6th PM
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DISCLAIMER : This Geographic Information System (GIS) and itscomponents are designed as a source of reference for answeringinquiries, for planning and for modeling. GIS is not intended, nor does itreplace legal description information in the chain of title and otherinformation contained in official government records such as the CountyClerk and Recorders office or the courts. In addition, the representationsof locations in this GIS cannot be substituted for actual legal surveys.
Project Number: 014-2878
Drawn By: JWH
Revision Date: 12/26/2014
Geology Map Ursa Operating CompanyTompkins PadGarfield County, CO Sec 5, T7S, R95W, 6th PM
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Author: M. Spinelli
0 500 1,000Feet
Notes / Comm en ts:
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Proposed Development
County Roads
Local Roads
±Revision: 0
Date: 5/6/2014
NRCS SO ILS KEY:
MAP SYMBOL SER IES NAME
F o r m 2 A - A t t a c h m e n t HForm 2 A - A t t a c h m e n t HNRCS S oi l s M ap
39.45995 -108.01407Section 5, Township 7 South, Range 95 West
To m p k i n s34
33
56
58
59
65
72
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Ildefonso stony loam (6-25% slopes)
Ildefonso stony loam (25-45% slopes)
Potts loam (6-12% slopes)
Potts-Ildefonso complex (12-25% slopes)
Potts-Ildefonso complex (25-45% slopes)
Torrifluvents (nearly level)
Wann sandy loam (1-3% slopes)
Wann sandy loam (3-6% slopes)
Attachment H – NRCS Soil Survey, Rifle Area
Map Symbol 58 – Potts-Ildefonso complex (12-25% slopes)
Strongly sloping to hilly soils are on mesas, alluvial fans and sides of valleys.
Elevation 5,000 to 6,500 feet
Average Annual
Precipitation Approximately 14 inches
Average Annual Air Temp Approximately 46 degrees F
Frost Free Days Approximately 120 da ys
Permeability Moderate to Low
Available Water Capacity Low to Moderate
Effective Rooting Depth 60 inches
Surface Runoff Medium
Erosion Hazard Moderate
Native Vegetation: Mainly wheatgrasses and sagebrush with an overstory of pinyon and Utah juniper.
The steep slopes limit community development. This soil complex is in capability subclass VIe,
nonirrigated.
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Proposed Development
County Roads
Local Roads
±Revision: 1
Date: 5/15/2014
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FEATURE PRESENT WITHIN 1,000 ft
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39.45995 -108.01407Section 5, Township 7 South, Range 95 West
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DISCLAIMER : This Geographic Information System (GIS) and itscomponents are designed as a source of reference for answeringinquiries, for planning and for modeling. GIS is not intended, nor does itreplace legal description information in the chain of title and otherinformation contained in official government records such as the CountyClerk and Recorders office or the courts. In addition, the representationsof locations in this GIS cannot be substituted for actual legal surveys.
Project Number: 014-2878
Drawn By: JWH
Revision Date: 12/26/2014
100/500 Year Floodplain Map Ursa Operating CompanyTompkins PadGarfield County, CO Sec 5, T7S, R95W, 6th PM
Figure
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