HomeMy WebLinkAboutEngineer's Subsurface Evaluation Report 08.01.201533 Four Wheel Drive Rd
Carbondale, CO 81623
970-309-5259
August 1, 2015 Project No. C1152
Kiel Williams
Kiel.f.williams@gmail.com
Subsurface Evaluation
Lot 15, Callicotte Ranch
Garfield County, Colorado
Kiel,
ALL SERVICE septic, LLC completed an onsite wastewater treatment system (OWTS) design dated June
10, 2015 for the proposed residence on the subject property. The property is located outside of
Carbondale, in an area where OWTSs are necessary. A site specific subsurface evaluation was
conducted to confirm subsurface conditions.
Legal Description:
Section: 24 Township: 7 Range: 88 Subdivision: Callicotte Ranch Lot: 15
SUBSURFACE
A preliminary geotechnical study was performed by HP Geotech and results are detailed in a report dated
April 19, 2002, Job Number 101 821 (enclosed). Percolation tests throughout the then -proposed
development averaged between 10 and 30 minutes per inch.
Profile pits were excavated throughout the then -proposed development, with the closest pit to the subject
property excavated on Lot 14 (P6). A Cat 420D backhoe was used to excavate the test pits. The materials
encountered in this test pit consisted of topsoil of 1 -foot, underlain by light brown, calcareous, slightly
moist, medium dense sandy silt and clay matrix to a maximum depth explored of 6 -feet where practical
digging refusal was encountered.
The subsurface was investigated on July 2, 2015 by ALL SERVICE Septic, LLC by digging two soil profile
test pit excavations (Test Pits #1 and #2) on the subject property. A visual and tactile soil analysis was
completed by Carla Ostberg at the time of excavation.
The materials encountered in Test Pit #1 consisted of 1 -foot of dark brown, moist, topsoil, underlain by
dense, light brown to tan sandy loam to 6.0 -feet, underlain by dense to very dense, tan to white loamy
sand (caliche) to a maximum depth explored of 7.0 -feet. No bedrock or groundwater was encountered.
The materials encountered in Test Pit #2 consisted of 1 -foot of dark brown, moist, topsoil, underlain by
dense, light brown to tan sandy loam to 3.0 -feet, underlain by dense to very dense, tan to white loamy
sand (caliche) to a maximum depth explored of 7.0 -feet. No bedrock or groundwater was encountered.
A sample was obtained from Test Pit #1 at approximately 2 to 3 -feet. The sieved sample formed a ball
' Carla Ostberg holds a Certificate of Attendance and Examination from the CPOW Visual and Tactile
Evaluation of Soils Training.
Page 2
and a ribbon less than 1.0 -inch before breaking. The sample had a blocky structure shape, strong
structure grade, and firm consistence. The texture was both gritty and smooth.
A sample was obtained from Test Pit #2 at approximately 3 -feet. The sieved sample formed a ball but no
ribbon. The sample had fine grain to blocky structure shape, strong structure grade, and firm
consistence.
July 2, 2015
Test Pit #1
Test Pit #2
Page 3
Based on the HP Geotech report and the site specific evaluation, the OWTS has been sized based on
Soil Type 2. A long term acceptance rate (LTAR) of 0.6 gallons per square foot has been used to
design the OWTS, in accordance with Table 10-1 presented in the Garfield County On -Site
Wastewater Treatment System Regulations, adopted April 14, 2014.
No changes to the June 10, 2015 OWTS design are necessary.
Sincerely,
ALL SERVICE septic, LLC
(7a ( 6V- 8
Carla Ostberg, MPH, REHS
GLgiStech
Hepworth-Pawlak Geotechnical, Inc.
5020 County Road 154
Glenwood Springs, Colorado 81601
Phone: 970-945-7988
Fax: 970-945-8454
hpgeo@hpgeotech.com
PRELIMINARY GEOTECHNICAL STUDY
PROPOSED CALLICOTTE RANCH
COUNTY ROADS 112 AND 103
GARFIELD COUNTY, COLORADO
JOB NO. 101 821
APRIL 19, 2002
RECEIVED APR 2 2 2002
PREPARED FOR:
MAGNA CASA, INC.
ATTN: JACK MANCINI
1700 E. LAS OLAS BOULEVARD, SUITE 206
FORT LAUDERDALE, FLORIDA 33301
HEPWORTH - PAWLAK GEOTECHNICAL, INC.
April 19, 2002
Magna Casa, Inc.
Attn: Jack Mancini
1700 E. Las Olas Boulevard, Suite 206
Fort Lauderdale, Florida 33301
Job No. 101 821
Subject: Report Transmittal, Preliminary Geotechnical Study, Proposed Callicotte
Ranch, County Roads 112 and 103, Garfield County, Colorado
Dear Mr. Mancini:
As requested, we have conducted a geotechnical study for the proposed development at
the subject site.
The property is suitable for the proposed development based on geologic and
geotechnical conditions. There are several conditions of a geologic nature the should be
considered in project planning and design. These conditions should not require major
modifications to the proposed development plan, but mitigation should be considered for
some.
Subsoils encountered in the exploratory throughout the property excavated generally
consist of relatively stiff, sandy silty clay soils and dense basalt fragments up to boulder
size in a sandy silt and clay matrix. Dense gravel alluvium was encountered below the
fine-grained soils at Pit 10. Groundwater was not encountered in the pits and the soils
are slightly moist to moist.
Spread footings placed on the natural subsoils and designed for an allowable bearing
pressure of 1,500 psf to 3,000 psf appear suitable at the building sites. The water tank
foundation should be designed for an allowable pressure of 1,500 psf, excluding the
weight of the water. There could be post construction settlement/heave if the fine-
grained bearing soils become wetted. Percolation testing indicates the subsoils are
generally suitable for infiltration septic disposal systems.
The report which follows describes our investigation, summarizes our findings, and
presents our recommendations suitable for planning and preliminary design. It is
important that we provide consultation during design, and field services during
construction to review and monitor the implementation of the geotechnical
recommendations.
If you have any questions regarding this report, please contact us.
Sincerely,
HEPWORTH - PAWLAK GEOTECHNICAL, INC.
Trevor L. Knell
Rev. by: DEH
TLK/ksw
r
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY 1
PROPOSED DEVELOPMENT 1
SITE CONDITIONS 2
GEOLOGIC SETTING 2
FORMATION ROCK 3
EVAPORITE DEFORMATION AND SOLUTION FEATURES 4
SURFICIAL SOIL DEPOSITS 4
FIELD EXPLORATION 5
SUBSURFACE CONDITIONS . 5
GEOLOGIC SITE ASSESSMENT 6
CONSTRUCTION RELATED SLOPE INSTABILITY 6
POTENTIALLY EXPANSIVE FOUNDATION CONDITIONS 7
REGIONAL EVAPORITE DEFORMATION AND SINKHOLES 7
EXCAVATION DIFFICULTIES 8
EARTHQUAKE CONSIDERATIONS 8
PRELIMINARY DESIGN RECOMMENDATIONS 8
FOUNDATIONS 9
WATER TANK 9
FLOOR SLABS 9
UNDERDRAIN SYSTEM 10
SITE GRADING 10
PAVEMENT SUBGRADE 10
SURFACE DRAINAGE 11
PERCOLATION TESTING 11
LIMITATIONS 12
REFERENCES 13
FIGURES 1 & 2 - GEOLOGIC MAP AND LOCATION OF EXPLORATORY
PITS
FIGURE 3 - LOGS OF EXPLORATORY PITS
FIGURE 4 - LEGEND AND NOTES
FIGURES 5 & 6 - SWELL -CONSOLIDATION TEST RESULTS
TABLE I - SUMMARY OF LABORATORY TEST RESULTS
TABLE II - PERCOLATION TEST RESULTS
PURPOSE AND SCOPE OF STUDY
This report presents the results of a preliminary geotechnical study for the
proposed Callicotte Ranch to be Iocated at County Roads 112 and 103, Garfield County,
Colorado. The project site is shown on Figs. 1 & 2. The purpose of the study was to
evaluate the geologic and subsurface conditions and their impact on the project. The
study was conducted in accordance with our proposal for geotechnical engineering
services to Land Design Partnership, dated November 28, 2001.
A field exploration program consisting of a reconnaissance, exploratory pits and
percolation testing was conducted to obtain information on the site and subsurface
conditions. Samples of the subsoils obtained during the field exploration were tested in
the laboratory to determine their classification, compressibility or swell and other
engineering characteristics. The results of the field exploration and laboratory and
percolation testing were analyzed to develop recommendations for project planning and
preliminary design. This report summarizes the data obtained during this study and
presents our conclusions and recommendations based on the proposed development and
subsurface conditions encountered.
PROPOSED DEVELOPMENT
The 180 acre Callicotte Ranch will be subdivided into twenty-nine, large
residential lots with an average lot size of about 4 acres, see Figs. 1 and 2. A network
of interior streets will provide primary access to the lots. The development will have a
central water distribution system. Each lot will have an individual waste disposal
system. The streets will be constructed by the developer. Building site preparation and
driveways will be the responsibility of the individual lot owners. It is expected that the
residences will be relatively large structures with outbuildings. At the time of this
study, grading plans for the streets and individual lots was not available.
If development plans change s bgnificantly from those described, we should be
notified to re-evaluate the recommendations presented in this report.
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SITE CONDITIONS
The project site is located on a rolling basalt plateau to the north and east of the
Roaring Fork River. The property covers parts of Sections 13 and 24, T. 7 S., R. 88
W. and is located about 3 miles northeast of Carbondale. Crystal Springs Road borders
the property on the east. The topography at the project site is shown by the contour
lines on Figs. 1 and 2. The narrow Crystal Springs Creek valley borders the property
on the south and a small tributary valley crosses through the property. Slopes along
these two valley sides are steep, typically in the range of 30% to 50%. Slopes on the
adjacent uplands are typically in the range of 10 % to 20%. Crystal Springs Creek is a
small perennial stream and a small perennial stream is also present in the southern part
of the tributary valley, but the upper reaches of this stream are ephemeral and only have
surface flow following heavy precipitation. The perennial streams are spring fed and
several contact springs and seeps are also present on the northern Crystal Springs valley
side near the contact of the Eagle Valley Evaporite and overlying basalt flows, see Fig.
2. The property was undeveloped ranch land at the time of this study. Much of the
property is irrigated hay fields. What appears to be a reclaimed borrow area is located
in the proposed open space near the northeast corner of the property. Vegetation
outside the irrigated fields is juniper trees with sage and other brush.
GEOLOGIC SETTING
The basalt plateau in the project area is a structural bench between the White
River uplift to the north and the Roaring Fork syncline to the south. These regional
geologic structures were formed during the Laramide orogeny about 40 to 70 million
years ago. Regional mapping indicates that basalt flows that overlie the Eagle Valley
Evaporite are the near surface formation rock in the project area (Kirkham and
Widmann, 1997). Surflcial soil deposits are mostly colluvium with some valley floor
alluvium. The principle geologic features in the project area are shown on Figs. 1 and
2. The basalt plateau in the project area lies near the center of the Carbondale
evaporite collapse center. The collapse center is a roughly a circular region with a
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diameter of about 16 miles and an area of about 200 square miles (Kirkham and
Widmann, 1997). As much as 4,000 feet of regional subsidence has occurred in the
collapse center as the result of dissolution and flowage of evaporite beneath the area.
Much of this subsidence may have occurred within the past 10 million years (Kirkham
and Widmann, 1997). If this is the case, the long-term average subsidence rate was
about 0.5 inch per 100 years. There is some local evidence of evaporite deformations
as recently as the late Pleistocene in the Carbondale collapse center, but no definitive
evidence of deformations during the post -glacial times, within about the past 15,000
years (Widmann and Others, 1998).
FORMATION ROCK
The Pennsylvanian -age Eagle Valley Evaporite (Pee) crops out locally on the
lower valley sides in the southwestern part of the property but basalt flows (Tb and
Tdb) underlie most of the project site.
Eagle Valley Evaporite: The Eagle Valley Evaporite is a thick sequence of
sedimentary rocks that are largely evaporite deposited in the central Colorado trough
about 300 million years ago. The evaporite consists of gray and tan gypsum, anhydrite
and locally occurring halite interbedded with siltstone, claystone and dolomite. The
rock varies from cemented and hard to non-cemented but firm. The bedding is usually
complexly folded because of flow in the plastic gypsum and anhydrite. The evaporite is
relatively soluble in fresh water and subsurface voids and associated sinkholes are
sometimes present in areas where the evaporite is near the surface in the region.
Basalt Flows: The Eagle Valley Evaporite in the project area is overlain by late
Miocene -age basalt flows. Radiometric age dates of the flows in the project area are
between 8.7 and 9.7 million years (Kirkham and Widmann, 1997). Relatively intact
basalt (Tb) is present in the in the southern part of the project area but the flows are
deformed and broken (Tdb) in the north part. The transition from intact to deformed
basalt is gradational. The intact basalt consist of multiple flows from 5 to 25 feet thick
of very dense and very hard basalt with secondary fracturing. The deformed basalt is
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very fractured and broken. It typically consists of large boulder sized, angular basalt
blocks with a sandy clay matrix. At the exploratory pits, intact and deformed basalt
was from less than one foot to greater than ten feet deep. The total thickness of the
basalt at the project site is uncertain in most areas but at least 100 feet of basalt is
present in the northwestern part of the property.
EVAPORITE DEFORMATION AND SOLUTION FEATURES
Regional geologic mapping shows the project site is located along the eastern
limb of a structural sag that starts in Heuschkel Park about two miles to the west and
curves just to the west of the project site and terminates to the northwest (Kirkham and
Widmann, 1997). The axis of the sag in the project area is shown on Figs 1 and 2.
Outcrops in the project area indicate that the basalt flows are tilted and have dips
between 22° and 28°, see Fig. 2. In the Heuschkel Park area, small displacement
normal faults parallel the sag axis, but faults have not been mapped in the project area
(Kirkham and Widmann, 1997).
A sinkhole in the deformed basalt is evident about 1,300 feet to the west of the
northwestern property corner on aerial photographs of the area we reviewed, see Fig. 2.
This sinkhole is also shown of the regional geology map (Kirkham and Widmann,
1997). Evidence of sinkholes was not observed on the property during our site
reconnaissance nor were sinkholes apparent on the aerial photographs reviewed.
SURFICIAL SOIL DEPOSITS
Valley floor alluvium (Qal) is present along the narrow valley floors of Crystal
Springs Creek and its tributary in the project area. Thin colluvium (Qc) is usually
present below the uplands elsewhere on the property. At the exploratory pits, from
less than one foot to greater than ten feet of colluvium was present above the intact and
deformed basalt. The colluvium is a low plasticity, sandy clay with scattered basalt
fragments from gravel to boulder size. Our laboratory tests show that the colluvium has
a moderate swell potential when wetted.
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PMID EXPLORATION
The field exploration for the project was conducted on December 27, 2001.
Eleven exploratory pits were excavated at the locations shown on Figs. 1 and 2 to
evaluate the subsurface conditions. The pits were dug with a Cat 420D backhoe and
logged by a representative of Hepworth-Pawlak Geotechnical, Inc.
Samples of the subsoils were taken with relatively undisturbed and disturbed
sampling methods. Depths at which the samples were taken are shown on the Logs of
Exploratory Pits, Fig. 3. The samples were returned to our laboratory for review by
the project engineer and testing.
SUBSURFACE CONDITIONS
Graphic logs of the subsurface conditions encountered at the site are shown on
Fig. 3. The subsoils generally consist of up to about 2 feet of organic topsoil overlying
relatively stiff, sandy silty clay soils and dense basalt fragments up to boulder size in a
sandy silt and clay matrix. Dense gravel alluvium was encountered below the clay in
Pit 10. Between 2' and 51/2 feet of clay overlies the basalt colluvium in Pits 1, 3, 4, 6,
8, 9 and 11.. Digging in the dense basalt gravel with backhoe equipment was difficult
due to the cobbles and boulders and refusal to digging was encountered in the deposit at
Pits 1,3,6and 8.
Laboratory testing performed on samples obtained from the pits included natural
moisture content and density, percent finer than sand size gradation analyses and
Atterberg limits testing. Results of swell -consolidation testing performed on relatively
undisturbed liner samples, presented on Figs. 5 & 6, indicate low compressibility under
existing moisture conditions and light loading and showed a low to moderate expansion
potential when wetted. The sample from Pit 7 at 5 feet showed a minor collapse
potential (settlement under a constant load) when wetted and moderate settlement with
increased loading. The laboratory testing is summarized in Table I.
No free water was encountered in the pits at the time of excavation and the
subsoils were slightly moist to moist.
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GEOLOGIC SITE ASSESSMENT
There are several conditions of a geologic nature that should be considered in
project planning and design. These conditions should not require major modifications
to the proposed development plan, but engineeredmitigation should be considered for
some. The geologic conditions and their anticipated influence on the project are
described below.
CONSTRUCTION RELATED SLOPE INSTABILITY
The regional geology map shows a landslide on the south side of the Crystal
Spring Creek valley to the south of the project area (Kirkham and Widmann, 1997).
The landside appears to be in the Eagle Valley Evaporite where contact springs
discharge near the contact with the overlying basalt flows. Similar conditions are
locally present on the north side of the valley in the project area. Although a landside
has not occurred on the north valley side, in our opinion, this area may be near a
critical stability state and development is not recommend on the steep northern Crystal
Creek valley side in the vicinity of the springs and seeps, see Fig. 2. The preliminary
development plans show the questionable area to be open space and the southwestern
part of Lot 28. Suitable building sites are present on Lot 28 on the plateau top to the
northeast of the steep valley side.
Elsewhere 011 the property we do not anticipate major problems with
construction related slope instability if the proposed grading is engineered and extensive
grading is not done on steep slopes. We should review the grading plans for the
common streets when the plans are available. Individual lot owners should not locate
buildings or driveways on slopes steeper than about 30% unless site specific
geotechnical studies are performed to evaluate the feasibility of the proposed grading.
Preliminary grading considerations are presented in the Preliminary Design
Recommendations - Site Grading section of this report.
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POTENTIALLY EXPANSIVE FOUNDATION CONDITIONS
Our laboratory tests show that the colluvium on the property has a low to
moderate swell potential when wetted. Preliminary recommendations to mitigate the
expansion potential for building foundations are discussed in the Preliminary Design
Recommendations - Foundations section of this report.
REGIONAL EVAPORITE DEFORMATION AND SINKHOLES
The project site is in an area where regional ground deformations have been
associated with evaporite solution and flow in the geologic past. These deformations
probably started about 10 million years ago, but it is uncertain if the deformations are
still active or if deformations have stopped. If deformations are still active, it appears
to be taking place over a broad area and there is no evidence of rapid deformation rates.
Because of this, the risk of problems with typical residential buildings appears to be
low. We are not aware of problems associated with regional evaporite deformations in
the area.
Sinkholes were not observed on the property in the field or on the aerial
photograph reviewed. However, a sinkhole is located about 1,300 feet to the west of
the northwestern property corner and sinkholes are present elsewhere in the region and
the property should not be considered sinkhole risk free. The sinkhole risk on the
property is viewed to be low and no greater than that present in many other parts of
Garfield County where the evaporite is near the surface. The potential for shallow
subsurface voids that could develop into sinkholes should be considered when planning
site specific geotechnical studies at specific building sites. If conditions indicative of
sinkhole related problems are encountered, the building site should be moved or the
feasibility of mitigation evaluated. Mitigation measures could include:
• Stabili7ation by Grouting
• Stabili7ation by Excavation and Backfilling
• Deep Foundation Systems
• Structural Bridging
• Mat Foundations
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Water features such as landscape ponds are not recommended near building sites
unless evaluated on a site specific basis. Home owners should be advised of the
sinkhole potential, since early detection of foundation distress and timely remedial
actions are important in reducing the cost of remediation, should a sinkhole start to
develop after construction.
EXCAVATION DIFFICULTIES
Dense, hard basalt is likely present at relatively shallow depths throughout the
project area. Difficult excavations should be expected, particularly in confined
excavations such as trenches. Ripping and blasting may be needed in some part of all
excavations that encounter dense, hard basalt.
EARTHQUAKE CONSIDERATIONS
The project area could experience moderately strong earthquake related ground
shaking. Modified Mercalli Intensity VI ground shaking should be expected during a
reasonable service life for the development, but the probability for stronger ground
shaking is low. Intensity VI ground shaking is felt by most people and causes general
alarm, but results in negligible damage to structures of good design and construction.
Occupied structures should be designed to withstand moderately strong ground shaking
with little or no damage and not to collapse under stronger ground shaking. The region
is in the Uniform Building Code, Seismic Risk Zone 1. Based on our current
understanding of the earthquake hazard in this part of Colorado, we see no reason to
increase the commonly accepted seismic risk zone for the area.
PRELIMINARY DESIGN RECOMMENDATIONS
The conclusions and recommendations presented below are based on the
proposed development, subsurface conditions encountered in the exploratory pits, and
our experience in the area. The recommendations are suitable for planning and
preliminary design but site specific studies should be conducted for individual lot
development.
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FOUNDATIONS
Bearing conditions vary depending on the specific location of the building on the
property. Based on the nature of the assumed construction, spread footings bearing on
the natural subsoils should be suitable at the building sites. We expect the footings can
be sized for an allowable bearing pressure in the range of 1,500 psf to 3,000 psf.
Expansive clays encountered in building areas may need to be removedor the footings
designed to impose a minimum dead load pressure to limit potential heave. Excavation
difficulty could be encountered at site with basalt boulders. Nested boulders and loose
matrix soils may need treatment such as enlarging footings or placing compacted fill or
concrete backfill. Foundation walls should be designed to span local anomalies and to
resist lateral earth loadings when acting as retaining structures. Below grade areas and
retaining walls should be protected from wetting and hydrostatic loading by use of an
underdrain system. The footings should have a minimum depth of 42 inches for frost
protection.
WATER TANK
The water tank is proposed to be an above ground, steel structure 24 feet high
with a diameter of 36 feet and a 200,000 gallon capacity located on the site as shown on
Fig.1. The foundation for the tank should bear on undisturbed native soils designed for
an allowable bearing pressure of 1,500 psf, excluding the weight of the water. We
should review the preliminary design plans and perform additional analysis as needed.
FLOOR SLABS
Slab -on -grade construction should be feasible for bearing on the natural soils.
There could be some post construction slab movement at sites with collapsible matrix or
expansive clays. To reduce the effects of some differential movement, floor slabs
should be separated from all bearing walls and columns with expansion joints. Floor
slab control joints should be used to reduce damage due to shrinkage cracking. A
minimum 4 -inch thick layer of free -draining gravel should underlie basement level slabs
to facilitate drainage and provide support.
H -P GEOTECH
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UNDERDRAIN SYSTEM
Although free water was not encountered in the exploratory pits, it has been our
experience in the area that local perched groundwater can develop during times of heavy
precipitation or seasonal runoff. An underdrain system should be provided to protect
below -grade construction, such as retaining walls, crawlspace and basement areas from
wetting and hydrostatic pressure buildup. The drains should consist of drainpipe
surrounded above the invert level with free -draining granular material. The drain
should be placed at each level of excavation and at least 1 foot below lowest adjacent
finish grade and sloped at a minimum 1% to a suitable gravity outlet.
SITE GRADING
The risk of construction -induced slope instability at the site appears low provided
the buildings are located in the less steep parts of the property and cut and fill depths are
limited. Cut depths for the building pads and driveway access should not exceed about
10 feet. Fills should be limited to about 10 feet deep, especially where they encroach
steep downhill sloping areas. Embankment fills should be compacted to at least 95 % of
the maximum standard Proctor density near optimum moisture content. Prior to fill
placement, the subgrade should be carefully prepared by removing all vegetation and
topsoil. The fill should be benched into the portions of the hillside exceeding 20%
grade. The on-site soils excluding oversized rock and topsoil should be suitable for use
in embankment fills.
Permanent unretained cut and fill slopes should be graded at 2 horizontal to
1 vertical or flatter and protected against erosion by revegetation, rock riprap or other
means. Oversized rock from embankment fill construction will tend to collect on the
outer face. This office should review site grading plans for the project prior to
construction.
PAVEMENT SUBGRADE
The on-site medium plastic clay soils have an AASHTO classification of A-6
with Group Indices of 14 and 18. These soils are considered poor for support of
pavement sections. The Hveem stabilometer 'R' value test resulted in a value of 5. An
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`R' value of 5 can be assumed for design of pavements in clay subgrade areas. The `R'
value should be considerably higher in the basalt fragment deposit areas. A subbase
material such as an import aggregate could be used in improve the clay subgrade. The
subgrade conditions at roadway grade should be evaluated for pavement design at the
time of construction.
SURFACE DRAINAGE
The grading plan for the subdivision should consider runoff from steep uphill
slopes through the project and at individual sites. Water should not be allowed to pond
which could impact slope stability and foundations. To limit infiltration into the bearing
soils next to buildings, exterior backfill should be capped with 1 to 2 feet of finer -
grained soils, be well compacted and have a positive slope away from the building fora
distance of 10 feet. Roof downspouts and drains should discharge well beyond the limits
of all backfill.
PERCOLATION TESTING
Percolation tests were conducted on December 28, 2001 to evaluate the
feasibility of an infiltration septic disposal systems at various locations across the
property. Percolation holes were excavated adjacent to the exploratory pits at the
locations shown on Figs. 1 and 2. The test holes (nominal 12 inch diameter by 12 inch
deep) were hand dug at the bottom of shallow backhoe pits and were soaked with water
and covered with rigid foam insulation one day prior to testing. The soils exposed in the
percolation holes are similar to those exposed in the adjacent exploratory pits (see Fig.
2). Average percolation rates ranged from about 10 to 30 minutes per inch. The
percolation test results are presented in Table II. Based on the subsurface conditions
encountered and the percolation test results, tested areas should be suitable for a
conventional infiltration septic disposal system. A civil engineer should design the
infiltration septic disposal system.
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LIbIITATIONS
This study has been conducted according to generally accepted geotechnical
engineering principles and practices in this area at this time. We make no warranty
either expressed or implied. The conclusions and recommendations submitted in this
report are based upon the data obtained from the field reconnaissance, review of
published geologic reports, the exploratory pits located as shown on Figs. 1 and 2,
percolation testing, the proposed type of construction and our experience in the area.
Our findings include interpolation and extrapolation of the subsurface conditions
identified at the exploratory pits and variations in the subsurface conditions may not
become evident until excavation is performed. If conditions encountered during
construction appear different from those described in this report, we should be notified
so that re-evaluation of the recommendations may be made.
This report has been prepared for the exclusive use by our client for planning and
preliminary design purposes. We are not responsible for technical interpretations by
others of our information. As the project evolves, we should provide continued
consultation, conduct additional evaluations and review and monitor the implementation
of our recommendations. Significant design changes may require additional analysis or
smodifications to the recommendations presented herein. We recommend on-site
observation of excavations and foundation bearing strata and testing of structural fill by
a representative of the geotechnical engineer.
Respectfully Submitted,
HEPWORTH - PAWLAK GEOTECHNICAL, INC.
Trevor L. Knell
Reviewed by:
Daniel E. Hardin,, P
TLK/ksw
cc: High Country
Land Design Partd
oger Neal
011 Liston
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REELRENCES
Kirkham, R.M. and Widmann, B.L., 1997, Geology Map of the Carbondale
Quadrangle, Garfield County, Colorado: Colorado Geological Survey Open File
97-3.
Widmann B. L. and Others, 1998, Preliminary Quaternary Fault and Fold Map and
Data Base of Colorado: Colorado Geological Survey Open File Report 98-8.
H -P GEOTECH
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Gal Valley Floor Alluvium
*
Approximate axis of structural sag.
o
Sinkhole L I
eoo 1t
t
Qls Landslide
Springs & Seeps scale: 1 In. = R
r. Contour Interval: 2 ft.
QTdb Deformed Basalt 2 C Strike and Dip:
Tb Basalt Flows (degrees)
121
■ Exploratory Pit & Percolation Test Site:
Pee Eagle Valley Evaporite
Approximate bcation.
101 821
HEPWORTH-PAWLAK
GEOTECHNICAL, Inc.
Callicotte Ranch Development -•Northern Part
Geology Map and Exploratory Pit Locations
Fig. 1
QC/QTdb J //j/
I
.
a. .yam '
Q
QcITb Qc
Qc./QTdb ))11
n
i
1
/
. •
`
1
UM A
11070.3 Sr*
u
113500 Sr*
_1f
I
4, Y
73.7*
120110
s\
..z Ilrei
Ao
.
Qc/QTdb
Qc/Tb
}A.
I
'llt`%�
� _
9.2i,.
�...
Qc/QTd. N
.'
Qc/Tb
oc/P
eTha
Q
���.— -
SP�nga Creek Qal
i
m
Qaler
/ Qis Qc/Tb
csi
Qc/QTdb
Explanation:
of Man-Placed Fill:
Contact:
Road fill, other fill and ground
disturbed by grading. Approximate boundary of map units.
Structural Sag:
Qc Colluvium
Approximate axis of structural sag.
Qal Valley Floor Alluvium 4 Sinkhole 0
I I
500 ft
1
Qls Landslide w Springs & Seeps Scale: 1 In. = 500 ft.
Contour Interval: 2 ft.
QTdb Deformed Basalt 2Y Strike and Dip:
Tb Basalt Flows (degrees)
P1
• Exploratory Pit & Percolation Test Site:
dee Eagle Valley Evaporlte Approximate location.
101 821
HEPWORTH-PAWLAK
GEOTECHNICAL, Inc.
Callicotte Ranch Development - Southern Part
Geology Map and Exploratory Pit Locations
Fig.2
a
li
r
4,
O
v
d
LL
m
0
Depth — Feet
111
5
— 10
0
5
10
0
5
10
PIT 1 PIT 2
PIT 5
PIT 9
-1
i WC=8.8
-200=92
LL=37
PI=20
R=5
WC=11.6
DD=103
WC=8.1
00=102
-200=87
LL=34
PI=17
101 821
WC=41.8
D0=70
-200=75
PIT 6
PIT 10
PIT 3
PIT 4
PIT 7 PIT 8
wC=9.8
00=81
[1- n
PIT 11
WC=10.6
D0=77
-200=70
WC=16.1
D0=91
0
5
10
0.
10
0 —.-
5
_
5
Note: Explanation of symbols is shown on Fig. 4.
HEPWORTH—PAWLAK
GEOTECHNICAL, INC.
10
Depth Feet
Depth — Feet
LOGS OF EXPLORATORY PITS
Fig. 3
fLEGEND:
f
_J
T
TOPSOIL; organic sandy silt and clay, dark brown.
CLAY (CL); silty, sandy, very stiff to hard, slightly moist to moist, brown to light brown, blocky,
calcareous with depth, low to medium plasticity.
BASALT GRAVEL, COBBLES AND BOULDERS (GM); sandy silt and clay matrix, medium dense,
slightly moist, light brown, calcareous.
GRAVEL AND COBBLES (GM—GP); .silty, sandy, medium dense, slightly moist, brown, rounded rock
Pit 10 only.
2" Diameter hand driven liner sample.
Disturbed bulk sample.
Practical digging refusal with Cat 420D backhoe.
NOTES:
1. Exploratory pits were excavated on December 27 and 28, 2001 with a backhoe.
2. Locations of exploratory pits were measured approximately by pacing from features on the site plan
provided.
3. Elevations of the exploratory pits were obtained by interpolation between contours on the site plan
provided.
3. Elevations of exploratory pits were not measured and logs of exploratory pits are drawn to depth.
4. The exploratory pit locations
by the method used.
5. The lines between materials
between material types and
and elevations should be considered accurate only to the degree implied
shown on the exploratory pit logs represent the approximate boundaries
transitions may be gradual.
6. No free water was encountered in the pits at the time of excavating. Fluctuations In water level may
occur with time.
7. Laboratory .Testing Results:
WC = Water Content ( % )
DD = Dry Density ( pcf )
+4 = Percent retained on No. 4 sieve
—200 = Percent passing No. 200 sieve
LL = Liquid Limit ( % )
PI = Plasticity Index ( % )
R = Hveem Stabilometer ."R" Value
101 821
HEPWORTH — PAWLAK
GEOTECHNICAL, INC.
LEGEND AND NOTES
Fig. 4
1
0
N 0
c
0
v 2
0
E
0
U 3
2
c
0
N 1
c
0
0.
x
w
0
c
0
1
L
0.
E
0
2
Moisture Content = 11.8 percent
Dry Density = 103 pcf
Sample of: Sandy Cloy
From: Pit 1 at 2.5 Feet
Expansion
upon
wetting
0.1
.0 0
APPLIED PRESSURE — ksf
100
Moisture Content = 16.1 percent
Dry Density = 91 pcf
Sample of:Sandy Clay Matrix
From: Pit 4 at 3 Feet
Expansion
upon
wetting
0.1
.0 10
APPLIED PRESSURE — ksf
100
101 821
HEFWORTH—PAWLAK
GEOTECHNICAL, INC.
SWELL CONSOLIDATION TEST RESULTS
Fig.5
Compression — Expansion %
Compression
1
0
1
2
3
0
1
2
3
4
Moisture Content = 11.6 percent
Dry Density = 103 pcf
Sample of: Sandy Clay
From: Pit 5 at 7 Feet
Expansion
upon
wetting
0.1
•0 10
APPLIED PRESSURE — ksf
100
Moisture Content = 9.8 percent
Dry Density = 81 pcf
Sample of: Calcareous Sandy Silty Clay
From: Pit 7 at 5 Feet
Compression
upon
wetting
0.1
.0 0
APPLIED PRESSURE — ksf
100
101 821
HEPWORTH—PAWLAK
GEOTECHNICAL, INC.
SWELL CONSOLIDATION TEST RESULTS
Fig. 6
N
0
0
z
m
0
U
M
J _J
Q 0
U
z �
U w
UJ j-
1- >-
O CC
w
V IQ
v CO cc
Q
J m
Or o
_
>-
1-- CC
CC Q
O 2
CL
w
2
1 II
sandy clay
calcareous sandy silty
claw
sanriw rinw II
sandy silty clay matrix II
HVEEM
STABILOMETER
5
20
17
N
M
M
PERCENT
PASSING
NO. 200
SIEVE
N
0
87
70
2
P
0
�
O
ae
to0
W_,
'¢ -
CC
,.t:—
=
f z
Z o
CO
O
70
CO
O
•-•r
81
N
O
77 1
IQ H
II
N r _
a o o
2 2 V
NOJ
N
W
d.
\
N
Ir:I
3 16.1
1- 3 8.8
a-
r
N
LL9
,-
W
M
5 10.6
a _
w_
o—
IISAMPLE I.
a
N
d'
in
I�
6)
HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE 11
PERCOLATION TEST RESULTS
JOB NO. '101 821
rage I OT 4
HOLE NO,
HOLE DEPTH
(INCHES)
LENGTH OF
INTERVAL
(MIN)
WATER DEPTH
AT START OF
INTERVAL
(INCHES)
WATER DEPTH
AT END OF
INTERVAL
(INCHES)
DROP IN
WATER
LEVEL
(INCHES)
AVERAGE
PERCOLATION
RATE
(MIN./INCH)
P-1
34
15
water added
7
5 3/4
' 1 1/4
20
5 3/4
4 1/2
1 1/4
4 1/2
3 3/4
3/4
3 3/4 2 3/4 1
7 1/2 6 3/4 3/4
6 3/4 6 3/4
6 5 1/4 3/4
5 1/4 4 1/2 3/4
P-2
39
15
7 1/2 6 3/4 3/4
30
6 3/4 6 3/4
6 5 1/2 - 1/2
5 1/2 5 1/2
5 41/2 1/2
4 1/2 • 4 1/2
4 3 1/2 1/2
31/2 3 1/2
P-3
38
15
101/2 8 21/2
10
8 61/2 1 1/2
6 1/2 5 1 1/2
water added
101/2 91/2 1
9 1/2 7 1/2 2
71/2 6 1/12
6 4 1/2 1 1/2
41/2 3 1 1/2
Note: Percolation test holes were hand dug in the bottom of backhoe pits adjacent to
explo atory pits and soaked on December 27, 2001. Percolation tests were conducted
on December 28, 2001. The average percolation rate were based on the last three
readings of each test.
HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE 11
PERCOLATION TEST RESULTS
JOB NO. 101 821
Note:
Percolation test holes were hand dug in the bottom of backhoe pits adjacent to
exploratory pits and soaked on December 27, 2001. Percolation tests were conducted
on December 28, 2001, The average percolation rate were based on the last three
readings of each test.
rayacor4+
HOLE NO.
HOLE DEPTH
(INCHES)
LENGTH OF
INTERVAL
(MIN)
WATER DEPTH
AT START OF
INTERVAL
(INCHES)
WATER DEPTH
AT END OF
INTERVAL
(INCHES)
DROP IN
WATER
LEVEL
(INCHES),
AVERAGE
PERCOLATION
RATE
(MIN./INCH)
P-4
42
15
water added
91/2
7
21/2
7
5 1/2
1 1/2
5 1/2 -
4 1/2
1
8 1/2
6 1/2
2
6 1/2
5 1/2
1
51/2
41/2
1
4 1/2
3 1/2
1
31/2
21/2
1
15
P-5
• 50. 1/2
10
7 1/2
6 3/4 •
3/4
20
6 3/4
6
3/4
6
5 1/4 •
3/4
5 1/4
4 3/4
1/2
4 3/4
4 1/4
1/2
4 1/4
3 3/4
1/2
3 3/4 .
3 1/4
1/2
3 1/4
2 3/4
1/2
P-6
29 1/2
10
8 1/4
7 1/2
3/4
20
7 1/2
7
1/2
7
6 1/2
1/2
6 1/2
6
1/2
6
5 1/2
1/2
5 1/2
5
1/2
5
4 1/2
1/2
41/2
4
1/2
Note:
Percolation test holes were hand dug in the bottom of backhoe pits adjacent to
exploratory pits and soaked on December 27, 2001. Percolation tests were conducted
on December 28, 2001, The average percolation rate were based on the last three
readings of each test.
HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE II
PERCOLATION TEST RESULTS
JOB NO. '101 821
Note: Percolation test holes were hand dug in the bottom of backhoe pits adjacent to
explo atory pits and soaked on December 27, 2001. Percolation tests were conducted
on December 28, 2001. The average percolation rate were based on the last three
readings of each test.
raye 3 OT 4
HOLE NO.
HOLE DEPTH
(INCHES)
LENGTH OF
INTERVAL
(MIN)
WATER DEPTH
AT START OF
INTERVAL
(INCHES)
WATER DEPTH
AT END OF
INTERVAL
(INCHES)
DROP IN
WATER
LEVEL
(INCHES)
AVERAGE
PERCOLATION
RATE
(MIN./INCH)
P-7
39
15
71/2
61/2
1
6 1/2
5 3/4
3/4
5 3/4
5
3/4
5
4 1/2
1/2
4 1/2
4
1/2
4
3 1/2
1/2
3 1/2
3
1/2
3
21/2
1/2
30
P-8
-
33
-
15
61/2
5 1/2
1
30
5 1/2
5
1/2
5
4 1/2
1/2
4 1/2
4
1/2
4
3 1/2
1/2
3 1/2
3
1/2
3
2 1/2
1/2
21/2
2
1/2
P-9
42
15
11
9 1/2 •
1 1/2
30
9 1/2
9
1/2
9
8
1
8
7 1/2
1/2
7 1/2
6
1/2
6
5
1
5
5
0
5
41/2
1/2
Note: Percolation test holes were hand dug in the bottom of backhoe pits adjacent to
explo atory pits and soaked on December 27, 2001. Percolation tests were conducted
on December 28, 2001. The average percolation rate were based on the last three
readings of each test.
HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE II
PERCOLATION TEST RESULTS
JOB NO. 101 821
HOLE NO.
HOLE DEPTH
(INCHES)
LENGTH OF
INTERVAL
(MIN)
WATER DEPTH
AT START OF
INTERVAL
(INCHES)
WATER DEPTH
AT END OF
INTERVAL
(INCHES)
DROP IN
WATER
LEVEL
(INCHES)
AVERAGE
PERCOLATION
RATE
(MIN./INCH)
P-10
42
10
8
71/2
1/2
71/2
7
1/2
30
7
6 3/4
1/4
. 6 3/4
6 1/2
1/4
6 1/2
6
1/2
6
5 3/4
• 1/4
5 3/4
5 1/4
1/2
51/4
5
1/4
P-11
42
15
12
11
1
30
11
10 1/2
1/2
10 1/2
10
. 1/2
10
9
1
9
9
0
9
8 1/2
1/2
8 1/2
8
1/2
8
71/2
1/2
Note: Perco ation test holes were hand dug in the bottom of backhoe pits adjacent to
explo atory pits and soaked on December 27, 2001, Percolation tests were conducted
on December. 28, 2001. The average percolation rate were based on the last three
readings of each test.
HEPWORTH• PAWLAK GEOTECHNICAL
July 15, 2003
Magna Casa, Inc.
Attn: Jack Mancini
1700 E. Las Olas Boulevard, Suite 206
Fort Lauderdale, Florida 33301
Hepworth-Pawlak Geotechnical, Inc.
5020 County Road 154 • •
Glenwood Springs, Colorado 81601
Phone: 970.945-7988
Fax: 970-945-8454
email: hpgeo®hpgeotech.com
Job No. 101 821
Subject: Radiation Potential, Proposed Callicotte Ranch, County Roads 112 and
103, Garfield County, Colorado
Dear Mr. Mancini:
As requested by Ron Liston, we have reviewed our previous geotechnical study for the
project with respect to radiation potential. We previously conducted a preliminary
geotechnical study for the project and presented our findings in a report dated April 19,
2002, Job No. 101 821.
The project site is not in a geologic setting that would indicate high concentrations of
radioactive minerals in the natural soils and underlying rock formation. However, there
is a potential that radon gas is present in the area. Based on our experience, we expect
radon gas concentrations to be low. It is difficult to assess future radon gas
concentrations in buildings before the buildings are constructed, Testing for radon gas
levels could be done when the residences and other occupied structures have been
completed. New buildings are often designed with provisions for ventilation of lower
enclosed areas should post construction testing show unacceptable radon gas
concentration.
If there are any questions or if we may be of further assistance, please let us know.
Sincerely,
HEPWORTH - PAWLAK it nc,,, HNICAL, INC.
• REc
.• Cc
• 5
Daniel E. Hardin, P. . 24443
Rev, by: SLP 3� �•% 7/i '� 3 . 4
DEH/ksw y'�oh �g NAL MSG\•
cc: High Country Engineers i "- Attn: Steven Douglas
Land Design Partnership - Attn: Ron Liston
Parker 303-841-7119 • Colorado Springs 719-633-5562 • Silvetthome 970-468-1989
.0i ,-,—,.
ts.kclz .... ,....-
cS:.;;Viti ' 12 Sil:r
,7:-` , .a. f r7, -..&'",—P A.,— rr,
C -K517.i-ii..., : Y
.
4.: r'filir.:*•Ca . • ' : .2 — : .
;;;.Z. Z,71,
-
,:- . 4•L":::-Crt't - c .-
Aspen -Gypsum Area, Colorado
SCS SOIL TYPE DESCRIPTIONS
the range condition deteriorates, mountain big
sagebrush, Douglas rabbitbrush, cheatgrass, and
annual weeds increase in abundance.
This unit responds well to applications of fertilizer, to
range seeding, and to proper grazing use. Areas that
are heavily infested with undesirable plants can be
improved by chemical or mechanical treatment.
This unit is well suited to hay and pasture. A
seedbed should be prepared on the contour or across
the slope where practical. For successful seeding, a
seedbed should be prepared and the seed drilled.
Applications of nitrogen and phosphorus fertilizer
improve the growth of forage plants. Proper stocking
rates, pasture rotation, and restricted grazing during wet
periods help to keep the pasture in good condition and
protect the soil from erosion. Furrow, border,
corrugation, and sprinkler irrigation systems are suited
to this soil. Pipe, ditch lining, or drop structures in ..
irrigation ditches facilitate irrigation and reduce the
hazard of ditch erosion.
This unit is well suited to irrigated crops. If properly
managed, it can produce 80 bushels of barley per acre
annually.
This unit is well suited to homesite development.
This map unit is in capability subclass IVe, irrigated
and nonirrigated. It is in the Deep Loam range site.
33—Earsman-Rock outcrop complex, 12 to 65
percent slopes. This map unit is on mountainsides and
ridges. Elevation is 6,000 to 8,500 feet. The average
annual precipitation is 14 to 16 inches, the average
annual air temperature is 42 to 44 degrees F, and the
average frost -free period is 80 to 105 days.
This unit is about 45 percent Earsman very stony
.sandy loam and 35 percent Rock outcrop. The Earsman.
soil is on the less steep slopes, and the areas of Rock
outcrop are in the steeper convex areas throughout the
unit.
Included in this unit are small areas of Arle and
Ansari soils and soils that are similar to the Earsman
soil but are deeper over bedrock. Included areas make
up about 20 percent of the total acreage.
The Earsman soil is shallow and somewhat
excessively drained. It formed in residuum and
colluvium derived dominantly from calcareous redbed
sandstone. About 5 to 10 percent of the surface is
covered with flagstones, and 5 to 15 percent is covered
with channery fragments. A thin layer of partially
decomposed needles, twigs, and leaves is on the
surface in many places. Typically, the surface layer is
reddish brown very stony sandy loam about 5 inches
thick. The substratum to a depth of 19 inches is very
channery sandy loam. The depth to hard, calcareous
sandstone ranges from 10 to 20 inches.
35
Permeability is moderately rapid in the Earsman soil.
Available water capacity is very low. The effective
rooting depth is 10 to 20 inches. Runoff is rapid, and
the hazard of water erosion is slight to severe on the
steeper slopes.
This unit is used mainly as rangeland or aswildlife
habitat. It also is used as a source of firewood and
posts.
The potential plant community on this unit is mainly
pinyon pine, Utah juniper, bluebunch wheatgrass,
bottlebrush squirreltail, Indian ricegrass, and western
wheatgrass. The potential production of the native
understory vegetation in normal years is about 500
pounds of air-dry vegetation per acre.
The slope limits access by livestock. The limited
accessibility results in overgrazing of the less sloping
areas. If the plant cover is disturbed, protection from
flooding is needed to control gullying, streambank
cutting, and sheet erosion.
This unit is suited to limited production of firewood.
The average annual production is 5 cords per acre. The
average stocking rate is 100 trees per acre. Special
care is needed to minimize erosion when the stands are
thinned and when other forest management practices
are applied.
This unit is severely limited as a site for homesite
development. Limitations include the shallow depth to
bedrock, the exposed bedrock, the slope, the rapid
runoff rate, and the very high hazard of water erosion.
This map unit is in capability subclass Vile,
nonirrigated. It is in the Pinyon -Juniper woodland site.
34—Empedrado loam, 2 to 6 percent slopes. This
deep, well drained soil is on fans and upland hills. It
formed in alluvium and eolian material. Elevation is
6,500 to 9,000 feet. The average annual precipitation is
15 to 18 inches, the average annual air temperature is
40 to 44 degrees F, and the average frost -free period is
75 to 95 days.
Typically, the surface layer is brown loam about 5
inches thick. The subsoil is clay loam about 35 inches
thick. The substratum to a depth of 60 inches or more is
clay loam. The soil is noncalcareous to a depth of 38
inches and calcareous below that depth.
Included in this unit are small areas of soils that are
similar to the Empedrado soil but have a darker, thicker
surface layer. Also included are small areas of soils that
are similar to the Empedrado soil but are silt loam or.
silty clay loam. Included areas make up about 20
percent of the total acreage.
Permeability is moderate in the Empedrado soil.
Available water capacity is high. The effective rooting
depth is 60 inches or more. Runoff is medium, and the
hazard of water erosion is slight.
36 Soil Survey
This unit is used as hayland or for crops. It is well
suited to hay and pasture. Grasses and legumes grow
well if adequate fertilizer is used. If properly managed,
the unit can produce 5 tons of irrigated grass hay per
acre annually.
The potential plant community on this unit is mainly
western wheatgrass, needleandthread, prairie
junegrass, mountain big sagebrush, and Douglas
rabbitbrush. Other plants that characterize this site are
muttongrass, Letterman needlegrass, common
snowberry, Utah serviceberry, and antelope bitterbrush.
The average annual production of air-dry vegetation is
about 1,500 pounds per acre. If the range condition.
deteriorates, mountain big sagebrush, Kentucky
bluegrass, Douglas rabbitbrush, and annual weeds
increase in abundance.
This unit is well suited to alfalfa and small grain
crops. It has few limitations. Maintaining crop residue
on or near the surface helps to control runoff and soil
blowing and helps to maintain tilth and the content of
organic matter. If properly managed, the unit can
produce 90 bushels of barley per acre annually.
This unit is suited to homesite development. The
main limitations are the shrink -swell potential and the
moderate permeability. The shrink -swell potential can
be minimized by thoroughly prewetting foundation
areas. The moderate permeability can be overcome by
increasing the size of the absorption field.
This map unit is in capability subclass IVe, irrigated
and nonirrigated. It is in the Deep Loam range site.
35—Empedrado loam, 6 to 12 percent slopes. This
deep, well drained soil is on fans and upland hills. It
formed in alluvium and eolian material. Elevation is
6,500 to 9,000 feet. The average annual precipitation is
about 15 to 18 inches, the average annual air
temperature is 40 to 44 degrees F, and the average
frost -free period is 75 to 95 days.
Typically, the surface layer is brown loam about 5
inches thick. The subsoil is clay loam about 35 inches
thick. The substratum to a depth of 60 inches is clay
loam. The soil is noncalcareous to a depth of 38 inches
and calcareous below that depth.
Included in this unit are small areas of soils that are
similar to the Empedrado soil but have a darker, thicker
surface layer. Also included are small areas of soils that
are similar to the Empedrado soil but are silt loam or
silty clay loam throughout. Included areas make up
about 20 percent of the total acreage.
Permeability is moderate in the Empedrado soil.
Available water capacity is high. The effective rooting
depth is 60 inches or more. Runoff is medium, and the
hazard of water erosion is moderate.
This unit is used as hayland or for crops. It is well
suited to hay and pasture. Grasses and legumes grow
well if adequate fertilizer is used. If properly managed,
the unit can produce 4 tons of irrigated grass hay per
acre annually.
This unit is well suited to alfalfa and small grain
crops. It is limited mainly by the slope in some areas.
Limiting tillage during seedbed preparation and
controlling weeds help to control runoff and erosion. All
tillage should be on the contour or across the slope. If
properly managed, the unit can produce 75 bushels of
barley per acre annually.
The potential plant community on this unit is mainly
western wheatgrass, needleandthread, prairie
junegrass, mountain big sagebrush, and Douglas
rabbitbrush. Other plants that characterize this site are
muttongrass, Letterman needlegrass, common
snowberry, Utah serviceberry, and antelope bitterbrush.
The average annual production of air-dry vegetation is
about 1,500 pounds per acre. If the range condition
deteriorates, mountain big sagebrush, Kentucky
bluegrass, Douglas rabbitbrush, and annual weeds
increase in abundance. These plants are dominant
when the range is in poor condition; therefore, livestock
grazing should be managed so that the desired balance
of the preferred species is maintained.
This unit is suited to homesite development. The
main limitations are the shrink -swell potential and the
slope. The shrink -swell potential can be minimized by
prewetting foundation areas. The slope is a
management concern if septic tank absorption fields are
installed. Absorption lines should be installed on the
contour.
This map unit is in capability subclass IVe, irrigated
and nonirrigated. It is in the Deep Loam range site.
36—Empedrado loam, 12 to 25 percent slopes.
This deep, well drained soil is on fans and upland hills.
It formed in alluvium and eolian material. Elevation is
6,500 to 9,000 feet. The average annual precipitation is
15 to 18 inches, the average annual air temperature is
40 to 44 degrees F, and the average frost -free period is
75 to 95 days.
Typically, the surface layer is brown loam about 5
inches thick. The subsoil is clay loam about 35 inches
thick. The substratum to a depth of 60 inches or more is
clay loam. The soil is noncalcareous to a depth of 38
inches and calcareous below that depth.
Included in this unit are small areas of soils that are
similar to the Empedrado soil but are silt loam or silty
clay loam. Also included are small areas of soils that
are similar to the Empedrado soil but have a darker,
thicker surface layer. Included areas make up about 15
percent of the total acreage.
Permeability is moderate in the Empedrado soil.
Aspen -Gypsum Area, Colorado 37
Available water capacity is high. The effective rooting
depth is 60 inches or more. Runoff is medium, and the
hazard of water erosion is moderate.
This unit is used as rangeland or for homesite
development.
If this unit is used for irrigated crops, the main
limitation is the slope. If properly managed, the unit can
produce 3.5 tons of irrigated grass hay per acre
annually.
The potential plant community on this unit is mainly
western wheatgrass, needleandthread, prairie
junegrass, mountain big sagebrush, and Douglas
rabbitbrush. Other plants that characterize this site are
muttongrass, Letterman needlegrass, common
snowberry, Utah serviceberry, and antelope bitterbrush.
The average annual production of air-dry vegetation is
about 1,500 pounds per acre. If the range condition
deteriorates, mountain big sagebrush, Kentucky
bluegrass, Douglas rabbitbrush, and annual weeds
increase in abundance.
If this unit is used for homesite development, the
main limitation is the slope.
This map unit is in capability subclass Vle, irrigated
�d nonirrigated. It is in the Deep Loam range site.
37—Etoe loam, 15 to 50 percent slopes. This deep,
well drained soil is on mountainsides. It formed in
alluvium and colluvium derived dominantly from
sandstone. Elevation is 7,700 to 8,500 feet. The
average annual precipitation is 18 to 20 inches, the
average annual air temperature is 38 to 40 degrees F,
and the average frost -free period is 70 to 80 days.
Typically, the surface layer is pinkish gray loam
about 8 inches thick. The subsurface layer is light
brownish gray extremely cobbly sandy loam about 16
inches thick. The next layer is extremely cobbly sandy
loam and extremely cobbly sandy clay loam about 11
inches thick. The subsoil is extremely stony sandy clay
loam about 25 inches thick.
Included in this unit are small areas of Cochetopa
and Ansel soils. Included areas make up about 15
percent of the total acreage.
Permeability is moderate in the Etoe soil. Available
water capacity is low. The effective rooting depth is
more than 60 inches. Runoff is medium, and the hazard
of water erosion is moderate or severe on the steeper
slopes.
This unit is used for timber, limited grazing, or wildlife
habitat. It is suited to the production of Douglas fir.
'ased on a site index of 72, the potential production per
re of merchantable timber is 5,800 cubic feet, or
24,000 board feet (International rule, 1/2 -inch kerf) from
an even -aged, fully stocked stand of trees 100 years
old. Generally, only foot slopes and ridges are
accessible. The slope limits harvesting in other areas.
The potential plant community on this unit is mainly
Douglas fir with an understory of nodding brome,
boxleaf myrtle, common juniper, mountain snowberry,
and Saskatoon serviceberry. The potential production of
the native understory vegetation in normal years is
about 250 pounds of air-dry vegetation per acre.
The production of vegetation suitable for livestock
grazing is limited by the overstory canopy. The slope
limits access by livestock. The limited accessibility
results in overgrazing of the less sloping areas.
If this unit is used for homesite development, the
'main limitations are large stones and the slope.
This map unit is in capability subclass Vile,
nonirrigated. It is in the Douglas Fir woodland site.
38—Evanston loam, 1 to 6 percent slopes. This
deep, well drained soil is on alluvial fans, terraces, and
valley sides. It formed in alluvium derived dominantly
from material of mixed mineralogy. Elevation is 6,500 to
8,000 feet. The average annual precipitation is 13 to 15
inches, the average annual air temperature is 42 to 46
degrees F, and the average frost -free period is 80 to 90
days.
Typically, the surface layer is brown loam about 14
inches thick. The subsoil is clay loam about 17 inches
thick. The substratum to a depth of 60 inches or more is
loam.
Included in this unit are small areas of Tridell,
Uracca, and Forelle soils. Also included are small areas
of soils that are similar to the Evanston soil but have
more stones. Included areas make up about 15 percent
of the total acreage.
Permeability is moderate in the Evanston soil.
Available water capacity is high. The effective rooting
depth is 60 inches or more. Runoff is slow, and the
hazard of water erosion is slight.
This unit is used mainly as rangeland. It also is used
for pasture, crops, or wildlife habitat. A few areas also
are used for homesite development.
The potential plant community on this unit is mainly
bluebunch wheatgrass, western wheatgrass,
muttongrass, Douglas rabbitbrush, and mountain big
sagebrush. Utah serviceberry, mountain snowberry,
prairie junegrass, and Ross sedge commonly are also
included. The average annual production of air-dry
vegetation is about 1,500 pounds per acre. If the range
condition deteriorates, mountain big sagebrush,
Douglas rabbitbrush, cheatgrass, and annual weeds
increase in abundance.
Suitable management practices include proper
grazing use and a planned grazing system. Brush
management improves deteriorated areas of range that
are producing more woody shrubs than were present in
Aspen -Gypsum Area, Colorado
Grasses and legumes grow well if adequate fertilizer is
used. Limiting tillage for seedbed preparation and
controlling weeds help to control runoff and erosion: If
properly managed, the unit can produce 3 tons of
irrigated grass hay or 60 bushels of barley per acre
annually.
The potential plant community on the Showalter soil
is mainly bluebunch wheatgrass, western wheatgrass,
prairie junegrass, Indian ricegrass, true
mountainmahogany, antelope bitterbrush, Saskatoon
serviceberry, and big sagebrush. The average annual
production of air-dry vegetation is about 900 pounds per
acre.
The potential plant community on the Morval soil is
mainly needleandthread, western wheatgrass,
muttongrass, prairie junegrass, and big sagebrush. The
average annual production of air-dry vegetation is about
1,500 pounds per acre.
The main limitation for range seeding or mechanical
treatment is the surface stoniness in areas of the
Showalter soil. Range seeding generally is restricted to
broadcasting because of this limitation.
This unit is poorly suited to homesite development.
The main limitations are the shrink -swell potential and
the stones throughout the profile.
This map unit is in capability subclass Vle, irrigated
and nonirrigaled.The Showalter soil is in the Loamy
Slopes range site, and the Morval soil is in the Deep
Loam range site.
95—Showalter-Morval complex, 15 to 25 percent
slopes. This map unit is on alluvial fans, high terraces,
and valley sides (fig. 7). Elevation is 7,000 to 8,500
feet. The average annual precipitation is 14 to 16
inches, the average annual air temperature is 42 to 44
degrees F, and the average frost -free period is 80 to 90
days.
This unit is about 45 percent Showalter very stony
loam and 35 percent Morval loam: The Showalter, soil is
in convex areas, and the Morval soil is in the more
concave areas.
Included in this unit are small areas of soils that are
similar to the Morval soil but have 30 to 50 percent
cobbles in the substratum. Included areas make up
about 20 percent of the total acreage.
The Showalter soil is deep and well drained. It
formed in alluvium derived dominantly from basalt.
About 10 to 15 percent of the surface is covered with
stones, 5 percent with cobbles, and 5 percent with
gravel. Typically, the surface layer is brown very stony
loam about 8 inches thick. The upper 3 inches of the
subsoil is very cobbly clay loam. The lower 28 inches is
very cobbly clay. The substratum to a depth of 60
inches or more is very cobbly clay loam.
Permeability is slow in the Showalter soil. Available
water capacity is moderate. The effective rooting depti
is 60 inches or more. Runoff is medium, and the haza
of water erosion is moderate.
The Morval soil is deep and well drained. It formed
alluvium derived dominantly from basalt. Typically, the
surface layer is brown loam about 7 inches thick. The
upper 12 inches of the subsoil is clay loam. The lower
inches is loam. The substratum to a depth of 60 inche
is loam. The soil is noncalcareous to a depth of 19
inches and calcareous below that depth.
Permeability is moderate in the Morval soil. Availabi
Water capacity also is moderate. The effective rooting
depth is 60 inches or more. Runoff is medium, and the
hazard of water erosion is slight.
This unit is used as rangeland or hayland or for
homesite development.
The potential plant community on the Showalter sof
is mainly bluebunch wheatgrass, western wheatgrass,
prairie junegrass, Indian ricegrass, true
mountainmahogany, antelope bitterbrush, Saskatoon
serviceberry, and big sagebrush. The average annual
production of air-dry vegetation is about 900 pounds p
acre.
The potential plant community on the Morval soil is
mainly needleandthread, western wheatgrass,
muttongrass, prairie junegrass, and big sagebrush. Th.
average annual production of air-dry vegetation is abo
1,500 pounds per acre.
The main limitation for range seeding or mechanical
treatment is the surface stoniness in areas of the
Showalter soil. Suitable management practices include
proper range use, deferred grazing, and rotation
grazing. Aerial spraying is suitable for brush
management.
If this unit is used for hay and pasture, the main
limitations are the surface stoniness, the slope, and th'
slow permeability in the Showalter soil. Grasses and
legumes grow well if adequate fertilizer is used.
This unit is very poorly suited to homesite
development. The main limitations are the slope, the
shrink -swell potential, and the stones throughout the
profile.
This map unit is in capability subclass Vle,
nonirrigated. The Showalter soil is in the Loamy Slope:
range site, and the Morval soil is in the Deep Loam
range site.
96—Southace cobbly sandy loam, 1 to 6 percent
slopes. This deep, well drained soil is on upland
terraces, mountainsides, and alluvial fans. It formed i
alluvium derived dominantly from redbed sandstone
shale intermixed with gypsiferous material. Elevation .s
6,000 to 7,000 feet. The average annual precipitation is
72 Soil Survey
The Rock outcrop consists mainly of barren
sandstone, shale, and basalt.
This unit is used as wildlife habitat. The native
vegetation is grasses, forbs, pinyon, and Utah juniper.
This unit is poorly suited to homesite development.
The main limitations are the slope, the depth to
bedrock, and large stones.
This map unit is in capability class VIII. No range site
is assigned.
106—Tridell-Brownsto stony sandy loams, 12 to 50
percent slopes, extremely stony. This map unit is on
terraces and mountainsides. Elevation is 6,400 to 7,700
feet. The average annual precipitation is 12 to 14
inches, the average annual air temperature is 42 to 44
degrees F, and the average frost -free period is 85 to
105 days.
This unit is about 45 percent Tridell soil and 35
percent Brownsto soil. About 5 to 10 percent of the
surface is covered with stones.
Included in this unit are small areas of Forelle and
Evanston soils in the less sloping cleared areas. Also
included are small areas of basalt Rock outcrop and
soils that are similar to the Tridell soil but have less
gravel and fewer stones. Included areas make up about
20 percent of the total acreage.
The Tridell soil is deep and somewhat excessively
drained. It formed in alluvium and colluvium derived
dominantly from sandstone and basalt. Typically, the
upper part of the surface layer is grayish brown stony
sandy loam about 2 inches thick. The lower part is
grayish brown very cobbly fine sandy loam about 7
inches thick. The upper 5 inches of the substratum is
very cobbly fine sandy loam. The next part is cobbly
sandy loam about 11 inches thick. Below this is 12
inches of very stony fine sandy loam. The lower part of
the substratum to a depth of 60 inches is very stony
loamy sand. Hard basalt is commonly below a depth of
about 60 inches. The soil is calcareous throughout. A
thin layer of partially decomposed needles, twigs, and
leaves is on the surface in many places.
Permeability is moderately rapid in the Tridell soil.
Available water capacity is low. The effective rooting
depth is 60 inches or more. Runoff is rapid, and the
hazard of water erosion is moderate.
The Brownsto soil is deep and well drained. It formed
in alluvium derived dominantly from coarse textured,
calcareous sandstone and basalt. Typically, the upper
part of the surface layer is light brownish gray stony
sandy loam about 4 inches thick. The lower part is light
brownish gray stony sandy loam about 7 inches thick.
The upper 19 inches of the substratum is very gravelly
sandy loam. The next 12 inches is very gravelly loamy
sand. The lower part to a depth of 60 inches is gravelly
sandy loam. A thin layer of partially decomposed
needles, twigs, and leaves is on the surface in many
places.
Permeability is moderate in the Brownsto soil.
Available water capacity is low. The effective rooting
depth is 60 inches or more. Runoff is rapid, and the
hazard of water erosion is moderate.
This unit is used mainly for livestock grazing or
wildlife habitat. It also is used for limited homesite
development, for Christmas trees, or as a source of
firewood and posts.
The potential plant community on the Tridell soil is
mainly pinyon pine and Utah juniper with an understory
of bluebunch wheatgrass, Indian ricegrass, Wyoming
big sagebrush, and muttongrass. Other plants that
characterize this site are bottlebrush squirreltail,
antelope bitterbrush, and true mountainmahogany. The
average annual production of air-dry vegetation is about
300 pounds per acre.
The potential plant community on the Brownsto soil is
mainly Wyoming big sagebrush, needleandthread,
Indian ricegrass, western wheatgrass, and scattered
pinyon pine and Utah juniper. Other plants that
characterize this site are bottlebrush squirreltail,
antelope bitterbrush, and true mountainmahogany. The
average annual production of native understory
vegetation is about 600 pounds per acre.
If the range condition deteriorates, Wyoming big
sagebrush, cheatgrass, and annual weeds increase in
abundance. Mechanical treatment is not practical
because of the very stony surface and the slope.
Suitable management practices include proper grazing
use and a planned grazing system. The slope limits
access by livestock. The limited accessibility results in
overgrazing of the less sloping areas. Selective thinning
of the pinyon and juniper stands improves the quality of
the understory for grazing and provides firewood, posts,
and Christmas trees.
The Tridell soil is suited to limited production of
pinyon pine and Utah juniper. The average annual
production is 5 cords per acre. The average stocking
rate is 150 trees per acre. To ensure sustained yields
and continued use, the kind of wood production should
be considered before the stands are thinned or cleared.
Special care is needed to minimize erosion when the
stands are thinned or cleared. Thinning the stands
generally promotes the growth of understory grasses
and young trees.
Only the less sloping areas of this unit are suited to
homesite development. The main limitations are the
slope and the stoniness. Erosion is a hazard in the
steeper areas. Only the part of the site that is used for
construction should be disturbed. Topsoil can be
stockpiled and used to reclaim areas disturbed during
Aspen -Gypsum Area, Colorado 73
construction. The gravel and cobbles in disturbed areas
should be removed if the site is landscaped, particularly
in areas used for lawns. Areas adjacent to hillsides are
occasionally affected by runoff, which may be
accompanied by the movement of rock debris.
Population growth has resulted in increased
construction of homes in areas of this unit.
This map unit is in capability subclass Vile,
nonirrigated. The Tridell soil is in the Pinyon -Juniper
woodland site, and the Brownsto soil is in the Stony
Foothills range site.
107—Uracca, moist-Mergel complex, 1 to 6 percent
slopes, extremely stony. This map unit is on alluvial
fans, benches, and valley side slopes. Elevation is
6,800 to 8,400 feet. The average annual precipitation is
16 to 19 inches, the average annual air temperature is
40 to 43 degrees F, and the average frost -free period is
75 to 95 days.
This unit is about 50 percent Uracca soil and 40
percent Mergel soil.
Included in this unit are small areas of soils that are
similar to the Uracca and Mergel soils but have a
thicker surface layer and a lower content of coarse
,agments. Included areas make up about 10 percent of
.ne total acreage.
The Uracca soil is deep and well drained. It formed in
alluvium derived dominantly from mixed igneous and
metamorphic material. About 3 to 15 percent of the
surface is covered with boulders, stones, cobbles, and
gravel. Typically, the surface layer is brown cobbly
sandy loam about 3 inches thick. The upper 5 inches of
the subsoil is cobbly sandy loam. The lower 7 inches is
very cobbly sandy clay loam. The substratum to a depth
of 60 inches or more is extremely cobbly loamy sand.
The content of coarse fragments ranges from 35 to 85
percent, by volume, in a major part of the surface layer
and subsoil.
Permeability is moderately rapid in the Uracca soil.
Available water capacity is low. The effective rooting
depth is 60 inches or more. Runoff is slow, and the
hazard of water erosion is slight.
The Mergel soil is deep and well drained. It formed in
glacial outwash. About 3 to 30 percent of the surface is
covered with boulders, stones, cobbles, and gravel.
Typically, the surface layer is grayish brown cobbly
loam about 8 inches thick. The upper 12 inches of the
substratum is very cobbly sandy loam. The lower part to
a depth of 60 inches is extremely stony sandy loam.
The content of coarse fragments ranges from 35 to 80
percent, by volume.
Permeability is moderate in the Mergel soil. Available
water capacity is low. The effective rooting depth is 60
inches or more. Runoff is slow, and the hazard of water
erosion is slight.
This unit is used mainly for irrigated hay and pasture.
It also is used for homesite development or rock
quarrying.
If this unit is used for hay and pasture, the main
limitation is the low available water capacity. Frequent
irrigation is needed. Applications of nitrogen and
phosphorus fertilizer improve the growth of forage
plants. Proper stocking rates, pasture rotation, and
restricted grazing during wet periods help to keep the
pasture in good condition and protect the soil from
erosion. Irrigation water can be applied by corrugation,
sprinkler, and flooding methods. Pipe, ditch lining, or
drop structures in irrigation ditches facilitate irrigation
and reduce the hazard of ditch erosion. If properly
managed, the unit can produce 4 tons of irrigated grass
hay per acre annually.
If this unit is used for homesite development, the
main limitations are the large stones and boulders on
and below the surface. Population growth has resulted
in increased construction of homes in areas of this unit.
Preserving the existing plant cover during construction
helps to control erosion. The gravel and cobbles in
disturbed areas should be removed if the site is
landscaped, particularly in areas used for lawns. The
effluent from septic tank absorption fields can surface in
downslope areas and thus create a health hazard. If the
density of housing is moderate or high, community
sewage systems are needed to prevent the
contamination of water supplies resulting from seepage
from onsite sewage disposal systems. Areas adjacent to
hillsides are occasionally affected by runoff, which may
be accompanied by the movement of rock debris.
This map unit is in capability subclass Vls, irrigated
and nonirrigated. It is in the Stony Loam range site.
108—Uracca, moist-Mergel complex, 6 to 12
percent slopes, extremely stony. This map unit is on
alluvial fans and valley side slopes. Elevation is 6,800
to 8,400 feet. The average annual precipitation is 16 to
19 inches, the average annual air temperature is 40 to
43 degrees F, and the average frost -free period is 75 to
95 days.
This unit is about 50 percent Uracca soil and 40
percent Mergel soil.
Included in this unit are small areas of soils that are
similar to the Uracca and Mergel soils but have a
thicker surface layer and a lower content of coarse
fragments. Included areas make up about 10 percent of
the total acreage.
The Uracca soil is deep and well drained. It formed in
alluvium derived dominantly from mixed igneous and
204
SCS SOIL INTERPRETATION TABLES5,,H survey
TABLE LL. --SANITARY FACILITIES --Continued
Soil name and
map symbol
Septic tank
absorption
fields
Sewage lagoon
areas
Trench
sanitary
landfill
Area
sanitary
landfill
Daily cover
for landfill
29*, 30*:
Rock outcrop.
33.
Dotsero
32
Dotsero
33*:
Batsman
Rock outcrop.
• 34
Empedrado
• 35
Empedrado
• a6
Empedrado
37
Etoe
38
Evanston
39, 40, 41
Evanston
42*
Fluvaquents
43*:
Forelle
Scownsto
44*:
Forelle
,rownsto
Severe:
slope.
Slight
Severe:
depth to rock,
slope.
Slight
Moderate:
slope.
Severe:
slope.
Severe:
slope.
Moderate:
percs slowly.
Severe:
slope.
Severe:
flooding,
wetness,
poor filter.
Moderate:
percs slowly,
slope.
Moderate:
slope.
Severe:
slope.
Severe:
slope.
See footnote at end of table.
Severe:
seepage,
slope.
Severe:
seepage.
Severe:
seepage,
depth to rock,
slope.
Severe:
seepage.
Severe:
seepage,
slope.
Severe:
seepage,
slope.
Severe:
slope.
Moderate:
seepage,
slope.
Severe:
slope.
Severe:
seepage,
flooding.
Severe:
slope.
Severe:
seepage,
slope.
Severe:
slope.
Severe:
seepage,
slope.
Severe:
seepage,
slope.
Severe:
seepage.
Severe:
depth to rock,
slope.
Severe:
seepage,
slope.
Severe:
seepage.
Severe:
depth to rock,
slope.
Severe: Severe:
seepage. seepage.
Severe: Severe:
seepage. seepage.
Severe: Severe:
seepage, seepage,
slope. slope.
Severe: Severe:
slope, slope.
large stones.
Slight Slight
Severe:
slope.
Severe:
flooding,
seepage,
wetness.
Moderate:
slope.
Moderate:
slope,
too sandy.
Severe:
slope.
Severe:
slope.
Severe:
slope.
Severe:
flooding,
seepage,
wetness.
Moderate:
slope.
Moderate:
slope.
Severe:
slope.
Severe:
slope.
Poor:
slope.
Fair:
small stones.
Poor:
area reclaim,
small stones,
slope.
Fair:
small stones.
Fair:
small stones,
slope.
Poor:
slope.
Poor:
large stones,
slope.
Good.
Poor:
slope.
Poor:
seepage,
too sandy,
small stones.
Fair:
slope.
Poor:
small stones.
Poor:
slope.
Poor:
small stones,
slope.
208 Soil Survey
TABLE 11. --SANITARY FACILITIES --Continued
Soil name and
map symbol
Septic tank
absorption
fields
Sewage lagoon
areas
Trench
sanitary
landfill
Area
sanitary
landfill
Daily cover
for landfill
94*:
Norval
• 95*:
Showalter
Norval
96
Southace
97
Southace
,uthace
100*:
Starley
Starman
101*:
Tanna
Pinelli
102*:
Tanna
Pinelli
103*:
Tanna
Moderate:
percs slowly,
slope.
Severe:
percs slowly,
slope.
Severe:
slope.
Moderate:
large stones.
Moderate:
s Lope,
large stones.
Severe:
slope.
Severe:
depth to rock.
Severe:
depth to rock.
Severe:
depth to rock,
percs slowly.
Severe:
percs slowly.
Severe:
depth to rock,
percs slowly.
Severe:
percs slowly.
Severe:
depth to rock,
percs slowly,
slope.
See footnote at end of table.
Severe:
slope.
Severe:
slope,
large stones.
Severe:
slope.
Severe:
seepage,
large stones.
Severe:
seepage,
slope,
large stones.
Severe:
seepage,
slope,
large stones.
Severe:
depth to rock,
slope.
Severe:
depth to rock,
slope.
Severe:
depth to rock.
Moderate:
slope.
Severe:
depth to rock,
slope.
Severe:
slope.
Severe:
depth to rock,
slope.
Moderate:
slope,
too clayey.
Severe:
slope,
large stones.
Severe:
slope.
Severe:
large stones.
Severe:
large stones.
Severe:
slope,
large stones.
Severe:
depth to rock.
Severe:
depth to rock.
Severe:
depth to rock.
Slight
Severe:
depth to rock.
Moderate:
slope,
Severe:
depth to rock,
slope.
Moderate:
slope.
Severe:
slope.
Severe:
slope.
Slight
Moderate:
slope.
Severe:
slope.
Severe:
depth to rock.
Severe:
depth to rock.
Slight
Slight
Moderate:
slope.
Moderate:
slope.
Severe:
slope.
Fair:
too clayey,
small stones,
slope.
Poor:
small stones,
slope.
Poor:
slope.
Poor:
small stones.
Poor:
small stones.
Poor:
small stones,
slope.
Poor:
depth to rock,
small stones.
Poor:
depth to rock.
Poor:
depth to rock.
Good.
Poor:
depth to rock.
Fair:
slope.
Poor:
depth to rock,
slope.
Aspen -Gypsum Area, Colorado 209
TABLE 11. --SANITARY FACILITIES --Continued
Soil name and
map symbol
Septic tank
absorption
fields
Sewage lagoon
areas
Trench
sanitary
landfill
Area
sanitary
landfill
Daily cover
for landfill
103*:
Ptnelli
104*:
Torriorthents
Camborthids
Rock outcrop.
105*:
Torriorthents
Rock outcrop.
Tridell
Brownsto
107*:
Uracca
Mergel
108*:
Uracca
Mergel
109*, 110*:
Uracca
Mergel
Severe:
parrs slowly,
slope.
Severe:
depth to rock,
slope.
Variable
Severe:
depth to rock,
slope.
Severe:
poor filter,
slope.
Severe:
slope.
Severe:
poor filter,
large stones.
Severe:
large stones.
Severe:
poor filter,
large stones.
Severe:
large stones.
Severe:
poor filter,
slope,
large stones.
Severe:
slope,
large stones.
See footnote at end of table.
Severe:
slope.
Severe:
depth to rock,
slope.
Variable
Severe:
depth to rock,
slope.
Severe:
seepage,
slope,
large stones.
Severe:
seepage,
slope,
large. stones.
Severe:
seepage,
large stones.
Severe:
large stones.
Severe:
seepage,
slope,
large stones.
Severe:
slope,
large stones.
Severe:
seepage,
slope,
large stones.
Severe:
slope,
large stones.
Severe:
slope.
Severe:
depth to rock,
slope.
Variable
Severe:
depth to rock,
slope.
Severe:
slope,
large stones.
Severe:
slope.
Severe:
slope.
Severe:
slope.
Variable
Severe:
slope.
Severe:
slope.
Severe:
slope.
Severe: Severe:
seepage, seepage.
large stones.
Severe: Slight
large stones.
Severe: Severe: -
seepage, seepage.
large stones.
Severe: Moderate:
large stones. slope.
Severe: Severe:
seepage, seepage,
slope, slope.
large stones.
Severe: Severe:
slope, slope.
large stones.
Poor:
slope.
Poor:
depth to rock,
small stones,
slope.
Variable.
Poor:
depth to rock,
small stones,
slope.
Poor:
slope.
Poor:
small stones,
slope.
Poor:
seepage,
large stones.
Poor:
large stones.
Poor:
seepage,
large stones.
Poor:
large stones.
Poor:
seepage,
large scones,
slope.
Poor:
large stones,
slope.
194 Soil Survey
TABLE 10. --BUILDING SITE DEVELOPMENT --Continued
Soil name and
map symbol
Shallow
excavations
Dwellings
without
basements
Dwellings
with
basements
Small
commercial
buildings
Localroads
and streets
Lawns and
landscaping
3 34
Empedrado
35
. Empedrado
36
Empedrado
37
Etoe
38
Evanston
39, 40,41
Evanston
42*
Fluvaquents
•
Forelle
3rownsto
44*:
Forelle
Brownsto
45
Forsey
46, 47
Slight
Moderate:
slope.
Forsey
48
Severe:
slope.
Severe:
slope.
Slight
Fughes
49
Goslin
Severe:
slope.
oslin
Severe:
cutbanks cave,
wetness.
Moderate:
slope.
Severe:
cutbanks cave.
Severe:
slope.
Severe:
cutbanks cave,
slope.
Moderate:
large stones.
Severe:
slope.
Moderate:
too clayey.
Slight
Slight Slight
Moderate:
slope.
Moderate: Moderate: Severe:
slope. slope. slope.
Severe: Severe: Severe:
slope. slope. slope.
Severe: Severe: Severe:
slope. slope. slope.
Slight Slight Slight
Severe:
slope.
See footnote at end of table.
Severe: Severe: Severe:
slope. slope. slope.
Severe: Severe: Severe:
flooding, flooding, flooding,
wetness. wetness. wetness.
Moderate: Moderate: Severe:
slope. slope. slope.
Moderate: Moderate: Severe:
slope. slope. slope.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Severe:
slope.
Severe:
shrink -swell:
Slight
.Severe:
slope.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Severe:
slope.
Severe:
shrink -swell.
Slight
Severe:
slope.
Severe:
slope.
Severe:
slope.
Moderate:
slope,
large stones.
Severe:
slope.
Severe:
shrink -swell.
Moderate:
slope.
Severe:
slope.
Moderate:
frost action.
Moderate:
slope,
frost action.
Severe:
slope.
Severe:
slope..
Slight
Severe:
slope.
Severe:
wetness,
flooding,
frost action.
Moderate:
slope.
Moderate:
slope.
Severe:
slope.
Severe:
slope.
Moderate:
frost action,
large stones.
Severe:
slope.
Severe:
shrink -swell,
low strength.
Slight
Moderate:
large stones.
Severe:
slope.
Moderate:
large stones,
slope.
Severe:
slope.
Severe:
slope.
Slight.
Severe:
slope.
Severe:
wetness.
Moderate:
large stones,
slope.
Moderate:
small stones,
droughty,
slope.
Severe:
slope.
Severe:
slope.
Severe:
large stones.
Severe:
large scones,
slope.
Moderate:
large stones.
Slight.
Severe:
slope.
Aspen -Gypsum Area, Colorado 197
TABLE 10. --BUILDING SITE DEVELOPMENT --Continued
Soil name and
map symbol
Shallow
excavations
Dwellings
without
basements
Dwellings
with
basements
Small
commercial
buildings
Local roads
and streets
Lawns and
landscaping
87*:
Tridell
88*:
Moyerson
Rock outcrop.
89
Mussel
90
Mussel
91
Mussel
92
Redrob
93
Rogert
94*:
Showalter
Marvel
® 95*: •
., Showalter
A
Marvel
96
Southace
97
Severe:
cutbanks cave,
slope.
Severe:
depth to rock,
slope.
Southace
98, 99
Severe:
cutbanks cave.
Southace
Severe:
cutbanks cave.
Severe:
cutbanks cave,
slope.
Severe:
cutbanks cave,
wetness.
severe:
depth to rock,
slope.
Moderate:
too clayey,
large stones,
slope.
Moderate:
slope.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Moderate:
large stones,
slope.
Severe:
slope.
See footnote at end of table.
Severe:
slope.
Severe:
shrink -swell,
slope.
Slight
Moderate:
slope.
Severe:
slope.
Severe:
flooding.
Severe:
slope,
depth to rock.
Moderate:
shrink -swell,
slope,
large stones.
Moderate:
shrink -swell,
slope.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Moderate:
slope,
large stones.
Severe:
slope.
Severe:
slope.
Severe:
depth to rock,
slope,
shrink -swell.
Slight
Moderate:
slope.
Severe:
slope.
Severe:
flooding,
wetness.
Severe:
depth to rock,
slope.
Moderate:
slope,
large stones.
Moderate:
slope,
shrink -swell.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Moderate:
slope,
large stones.
Severe:
slope.
Severe:
slope.
Severe:
shrink -swell,
slope.
Slight
Severe:
slope.
Severe:
slope.
Severe:
flooding.
Severe:
slope,
depth to rock.
Severe:
slope.
Severe:
slope.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Severe:
slope.
Severe:
slope.
Severe:
slope.
Severe:
low strength,
slope,
shrink -swell.
Moderate:
frost action.
Moderate:
slope,
frost action.
Severe:
slope.
Moderate:
wetness,
flooding.
Severe:
depth to rock,
slope.
Moderate:
slope,
frost action,
shrink -swell.
Moderate:
low strength,
slope,
frost action.
Severe:
slope.
Severe:
slope.
Moderate:
large stones.
Moderate:
slope,
large stones.
Severe:
slope.
Severe:
slope.
Severe:
slope,
thin layer.
slight.
Moderate:
slope.
Severe:
slope.
Moderate:
wetness.
Severe:
small scones,
slope.
Severe:
large stones.
Moderate:
slope.
Severe:
large stones,
slope.
Severe:
slope.
Severe:
droughty.
Severe:
droughty.
Severe:
droughty,
slope.
'98 Soil Survey
TABLE 10. --BUILDING SITE DEVELOPMENT --Continued
Soil name and
map symbol
Shallow
excavations
Dwellings
without
basements
Dwellings
with
basements
Small
commercial
buildings
Local roads
and streets
Lawns and
landscaping
100*:
Starley
Starman
101*:
Tanna
P inelli
102*:
Tanna
P inelli
103*:
Tanna
Pinelli
104*:
Torriorthents----
Camborthids
Rock outcrop.
105*:
Torriorthents
Rock outcrop.
0 106*:
Tridell
Severe:
depth to rock.
Severe:
depth to rock.
Moderate:
depth to rock,
too clayey.
Moderate:
too clayey.
Moderate:
depth to rock,
too clayey,
slope.
Moderate:
too clayey,
slope.
Severe:
slope.
Severe:
slope.
Severe:
depth to rock,
slope.
Variable
Severe:
depth to rock,
slope.
Severe:
cutbanks cave,
slope.
See footnote at end of table.
Severe: Severe:
depth to rock. depth to rock.
Severe: Severe:
depth to rock. depth to rock.
Severe:
shrink -swell.
Moderate:
shrink -swell.
Severe:
shrink -swell.
Moderate:
shrink -swell,
slope.
Severe:
shrink -swell,
slope.
Severe:
slope.
Severe:
slope,
depth to rock.
Variable
Severe:
slope,
depth to rock.
Severe:
slope.
Severe:
shrink -swell.
Moderate:
shrink -swell.
Severe:
shrink -swell.
Moderate:
slope,
shrink -swell.
Severe:
slope,
shrink -swell.
Severe:
slope.
Severe:
depth to rock,
slope.
Variable
Severe:
depth to rock,
slope.
Severe:
slope.
Severe:
slope,
depth to rock.
Severe:
slope,
depth to rock.
Severe:
shrink -swell.
Moderate:
shrink -swell.
Severe:
shrink -swell,
slope.
Severe:
slope.
Severe:
shrink -swell,
slope.
Severe:
slope.
Severe:
slope,
depth to rock.
Variable
Severe:
slope,
depth to rock.
Severe:
slope.
Severe:
depth to rock.
Severe:
depth to rock.
Severe:
shrink -swell,
low strength.
Moderate:
shrink -swell,
low strength.
Severe:
shrink -swell,.
low strength.
Moderate:
shrink -swell,
low strength,
slope.
Severe:
shrink -swell,
low strength,
slope.
Severe:
slope.
Severe:
depth to rock,
slope.
Variable
Severe:
depth to rock,
slope.
Severe:
slope.
Severe:
small stones,
depth to rock.
Severe:
small stones,
depth to rock.
Moderate:
depth to rock.
Slight.
Moderate:
slope,
depth to rock.
Moderate:
slope.
Severe:
slope.
Severe:
slope.
Severe:
slope,
depth to rock.
Variable.
Severe:
slope,
depth to rock.
Severe:
slope.