HomeMy WebLinkAbout1.04 Geo, NRCS soil reportGeologic and Soil Hazards Report
Grand River Gathering LLC
High Mesa Compressor Station
OA Project No. 012-0732
826 21 ½ Road | Grand Junction, CO 81505 | TEL 970.263.7800 | FAX 970.263.7456
Grand River Gathering LLC Olsson Associates
High Mesa Compressor Station Grand Junction, CO
February 2012 OA Project # 012-0539
1
GEOLOGIC AND SOIL HAZARDS REPORT
Introduction
Grand River Gathering LLC. has proposed the High Mesa Compressor Station Facility that will
be located south of Parachute and I-70, west of Richardson Road and lies between Dry Creek
and Pete and Bill Creek in Garfield County Colorado. This proposed Compressor Station will be
located in Section 36, Township 7 South, Range 96 West, of the Sixth Principal Meridian. The
vicinity of this proposed Compressor Station Facility is shown on a map provided in as an
attachment to this document.
The Grand River Gathering LLC, Compressor Station Facility project is located on the eastern
edge of the Piceance Basin near the Grand Hogback consisting of approximately 2,200 acres.
It lies adjacent to areas undergoing natural gas development by Noble Energy Inc. and Grand
River Gathering LLC. The natural gas resources that are being developed are underlain by
bedrock of the Tertiary age Wasatch Formation, including the lower Fort Union Equivalent at the
base and the Ohio Creek Formation.
Geology
The proposed project is located near the eastern margin of the Piceance Basin; an irregularly-
shaped elongated basin formed by tectonic forces that downwarped the earth’s crust as a result
of the uplift of the Colorado Rocky Mountains. Areas on all sides of the Piceance Basin have
been uplifted by these same tectonic forces.
Structural Geology
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 southwest, the Douglas Creek arch to the west-
northwest, and the Axial Basin uplift to the north (Grout and Verbeek, 1992).
The Grand Hogback monocline is a sinuous feature comprised of Upper Cretaceous age
bedrock of the Mesaverde Group, which includes the Williams Fork Formation and the
underlying Mancos Shale. The Grand Hogback forms part of the boundary between two major
physiographic provinces, the Colorado Plateau and the Rocky Mountain foreland. The Grand
Hogback bends abruptly to the north of the Gibson Gulch quadrangle and strata along the west-
Grand River Gathering LLC Olsson Associates
High Mesa Compressor Station Grand Junction, CO
February 2012 OA Project # 012-0539
2
to southwest-facing, steep limb of the monocline typically dip basinward at an angle of 45° or
are even overturned in some areas (Grout and Verbeek, 1992). A series of west-northwest
trending, broad, gentle anticlines and synclines, are present within the Piceance Basin to the
west of the Grand Hogback. The Wolf Creek anticline and the Divide Creek anticline are the
two closest of these structures. The axis of the Divide Creek anticline crosses the southwestern
part of the Gibson Gulch quadrangle. There are a total of eight joint sets, or fracture-pattern
trends, that have been mapped in the Wasatch and Mesaverde Group bedrock units in the area
(Grout and Verbeek, 1992). These joint sets are the result of structural deformation of these
sedimentary rock units through geologic time.
Surficial Geology
The location of the proposed facility is underlain by bedrock of the Tertiary age Wasatch
Formation, including the lower Fort Union Equivalent at the base and the Ohio Creek Formation.
The Wasatch Formation is divided into an upper section that ranges from 400 feet to 1,600 feet
thick, a middle section that ranges from 0 to 400 feet thick, and a lower section that ranges from
400 feet to 900 feet thick. The upper section consists of variegated shale and clay and some
lenticular sandstone, conglomerate, and limestone beds. The middle section consists of
massive fine-to coarse-grained sandstone that is gray to brown in color, in part conglomeratic,
and forms conspicuous ledges where exposed in outcrop. The lower section is composed of
variegated shale and clay and some lenticular beds of sandstone, conglomerate, and limestone.
Soils
According to information prepared by the Natural Resources Conservation Commission Soil
Survey, soils in these sections have been mapped as Ildefonso stony loam, (34), Potts loam,
(56), and the Potts-Ildefonso complex, (58). A copy of a NRCS Custom Soil Resource Report
for the project site has been provided.
Ildefonso stony loam (34) soils are developed on 25 percent to 45 percent slopes and consist of
well drained soils in land setting of alluvial fans, and valley sides. Elevations range from 5,000
to 6,500 feet above mean sea level. The parent material of this soil is mixed alluvium derived
from basalt.
The Potts loam (56) is developed on 6 percent to 12 percent slopes, at elevations of 5,000 to
7,000 feet. Found in landform setting of valley sides, benches, and mesas. The parent material
of this soil is alluvium derived from basalt and/or alluvium derived from sandstone and shale.
The Potts-Ildefonso complex (58) soils are developed on 12 to 25 percent slopes, and consist of
well drained soils on mountainsides and ridges at elevations of 5,000 to 6,500 feet. These soils
are found in landform setting of valley sides, alluvial fans, and mesas. The parent material of
this soil is alluvium derived from basalt and/or alluvium derived from sandstone and shale.
Grand River Gathering LLC Olsson Associates
High Mesa Compressor Station Grand Junction, CO
February 2012 OA Project # 012-0539
3
Conclusions and Summary
According to the information provided by Garfield County, Colorado - GIS Department pertaining
to the location of the Compressor Station Facility, the overall geologic and soil hazards appear
to be, minor slope hazards, and low soil hazards.
As depicted on the attached Slope Hazards Map, the location for the proposed facility is not
within any identified slope hazard areas. The nearest slope hazard area exists approximately
1.5 miles northwest of the proposed site.
Stormwater controls and best management practices should take into consideration the geology
and soil types present at this location. These engineering controls and practices should be
used temporarily and permanently to divert stormwater away from the construction areas and to
prevent additional weight which could trigger a debris flow or landslide. Pits are required to be
lined by COGCC rules, but pit liners may also prevent water infiltration into unconsolidated
sediments which could trigger slope failure. Pits and catchment basins should be sited and
designed so as not to add weight to potentially unstable areas.
Olsson appreciates the opportunity to provide this information to Grand River Gathering LLC
pertaining to the assessment of geologic and soil hazards associated with the proposed High
Mesa Compressor Station Facility in Garfield County, Colorado. Olsson can conduct field work
to assist with the site specific assessments of the proposed project, to determine the degree to
which these hazards may affect the specific locations.
Sincerely,
Olsson Associates Inc.
Tammie Lee Crossen
Associate Geologist
Attachments: Figure V-1 – Vicinity Map
Figure SM- 1 – Soils Map
Figure SH- 1 – Surface Hazards
Figure G-1 – Geology
Grand River Gathering LLC Olsson Associates
High Mesa Compressor Station Grand Junction, CO
February 2012 OA Project # 012-0539
4
References
Grout, Marilyn A. and Verbeek, Earl 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.
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, Colorado - GIS Department http://www.garfield-county.com/
70
6
Parachute
High Mesa Compressor Station
Legend
High Mesa Compressor Station
2409-361-00-048 (Area: 320 acres)
3-mile radial circle
Highway/Interstate
County RoadsParcels 0 1 20.5 Miles
3-mile radium indicated by dark red circle
PROJECT NO:
DRAWN BY:
DATE:
012-0539
Jenna Muhlbach
3/12/12
VICINITY MAPGRAND RIVER GATHERING, LLC.HIGH MESA COMPRESSORSTATIONGARFIELD COUNTY, COLORADO
826 21-1/2 ROADGRAND JUNCTION,CO 81505TEL 970.263.7800FAX 970.263.7456
FIGURE
V - 12
High Mesa Compressor Station
66
34
56
58
34
58
34
58
Legend
High Mesa Compressor Station
ParcelsHighway/InterstateCounty Roads
Soil Type33 - Ildefonso stony loam, 6-25% slopes34 - Ildefonso stony loam, 25-45% slopes56 - Potts loam, 6-12% slopes58 - Potts-Ildefonso complex, 12-25% slopes66 - Torriorthents-Camborthids-Rock outcrop complex, steep67 - Torriothents-Rock outcrop complex, steep
0 400 800200Feet
PROJECT NO:
DRAWN BY:
DATE:
012-0539
Jenna Muhlbach
3/9/12
SOILS MAPGRAND RIVER GATHERING, LLC.HIGH MESA COMPRESSORSTATIONGARFIELD COUNTY, COLORADO
826 21-1/2 ROADGRAND JUNCTION,CO 81505TEL 970.263.7800FAX 970.263.7456
FIGURE
SM - 14
70 6
High Mesa Compressor Station
Stone Quarry
Spring Creek
Wallace Creek
Gardner
Tamarisk
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Morningstar
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Legend
High Mesa Compressor Station
SlopeHazard
Parcels - 2409-361-00-048
Parcels
Highway/Interstate
County Roads 0 0.5 10.25 Miles
Slope data obtained from the Garfield County GIS
PROJECT NO:
DRAWN BY:
DATE:
012-0539
Jenna Muhlbach
3/27/12
SLOPE HAZARDS MAPGRAND RIVER GATHERING, LLC.HIGH MESA COMPRESSORSTATIONGARFIELD COUNTY, COLORADO
826 21-1/2 ROADGRAND JUNCTION,CO 81505TEL 970.263.7800FAX 970.263.7456
FIGURE
SH - 15
High Mesa Compressor Station
Two
Qgo
Qgo
Legend
Geology TypeQgo - Old Gravels and AlluviumTwo - Wasatch Formation & Ohio Creek Formation
High Mesa Compressor Station
Parcels - 2409-361-00-048Parcels
Highway/InterstateCounty Roads 0 500 1,000250Feet
Geologic Data obtained from the USGS
PROJECT NO:
DRAWN BY:
DATE:
012-0539
Jenna Muhlbach
3/27/12
GEOLOGY MAPGRAND RIVER GATHERING, LLC.HIGH MESA COMPRESSORSTATIONGARFIELD COUNTY, COLORADO
826 21-1/2 ROADGRAND JUNCTION,CO 81505TEL 970.263.7800FAX 970.263.7456
FIGURE
G - 13
NRCS Soils Report
Grand River Gathering LLC
High Mesa Compressor Station
OA Project No. 012-0732
826 21 ½ Road | Grand Junction, CO 81505 | TEL 970.263.7800 | FAX 970.263.7456
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Rifle Area, Colorado,
Parts of Garfield and
Mesa Counties
High Mesa Compressor Station
Natural
Resources
Conservation
Service
May 15, 2012
Preface
Soil surveys contain information that affects land use planning in survey areas. They
highlight soil limitations that affect various land uses and provide information about
the properties of the soils in the survey areas. Soil surveys are designed for many
different users, including farmers, ranchers, foresters, agronomists, urban planners,
community officials, engineers, developers, builders, and home buyers. Also,
conservationists, teachers, students, and specialists in recreation, waste disposal,
and pollution control can use the surveys to help them understand, protect, or enhance
the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil properties
that are used in making various land use or land treatment decisions. The information
is intended to help the land users identify and reduce the effects of soil limitations on
various land uses. The landowner or user is responsible for identifying and complying
with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some cases.
Examples include soil quality assessments (http://soils.usda.gov/sqi/) and certain
conservation and engineering applications. For more detailed information, contact
your local USDA Service Center (http://offices.sc.egov.usda.gov/locator/app?
agency=nrcs) or your NRCS State Soil Scientist (http://soils.usda.gov/contact/
state_offices/).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic
tank absorption fields. A high water table makes a soil poorly suited to basements or
underground installations.
The National Cooperative Soil Survey is a joint effort of the United States Department
of Agriculture and other Federal agencies, State agencies including the Agricultural
Experiment Stations, and local agencies. The Natural Resources Conservation
Service (NRCS) has leadership for the Federal part of the National Cooperative Soil
Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Soil Data Mart Web site or the NRCS Web Soil Survey. The Soil
Data Mart is the data storage site for the official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, age, disability, and where
applicable, sex, marital status, familial status, parental status, religion, sexual
orientation, genetic information, political beliefs, reprisal, or because all or a part of an
individual's income is derived from any public assistance program. (Not all prohibited
bases apply to all programs.) Persons with disabilities who require alternative means
2
for communication of program information (Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a
complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400
Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272
(voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and
employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................6
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions........................................................................................11
Rifle Area, Colorado, Parts of Garfield and Mesa Counties............................13
34—Ildefonso stony loam, 25 to 45 percent slopes....................................13
56—Potts loam, 6 to 12 percent slopes......................................................13
58—Potts-Ildefonso complex, 12 to 25 percent slopes...............................14
66—Torriorthents-Camborthids-Rock outcrop complex, steep...................15
67—Torriorthents-Rock outcrop complex, steep.........................................17
Soil Information for All Uses...............................................................................19
Suitabilities and Limitations for Use....................................................................19
Building Site Development..............................................................................19
Corrosion of Concrete.................................................................................19
Corrosion of Steel........................................................................................22
Local Roads and Streets.............................................................................25
Construction Materials....................................................................................30
Sand Source................................................................................................30
Topsoil Source............................................................................................35
Land Classifications........................................................................................39
Ecological Site ID: NRCS Rangeland Site..................................................39
Land Management..........................................................................................42
Mechanical Site Preparation (Surface)........................................................42
Water Management........................................................................................46
Pond Reservoir Areas.................................................................................47
Excavated Ponds (Aquifer-Fed)..................................................................51
Soil Properties and Qualities..............................................................................55
Soil Qualities and Features.............................................................................55
Depth to Any Soil Restrictive Layer.............................................................55
Drainage Class............................................................................................58
Hydrologic Soil Group.................................................................................61
Representative Slope..................................................................................65
Unified Soil Classification (Surface)............................................................68
Water Features...............................................................................................71
Flooding Frequency Class...........................................................................71
Ponding Frequency Class...........................................................................75
Soil Reports........................................................................................................79
Building Site Development..............................................................................79
Roads and Streets, Shallow Excavations, and Lawns and Landscaping....79
Soil Chemical Properties.................................................................................82
Chemical Soil Properties.............................................................................82
4
Soil Physical Properties..................................................................................86
Particle Size and Coarse Fragments...........................................................86
Physical Soil Properties...............................................................................90
Soil Qualities and Features.............................................................................95
Soil Features...............................................................................................95
Water Features...............................................................................................98
Water Features............................................................................................98
Water Management......................................................................................101
Ponds and Embankments.........................................................................101
References..........................................................................................................104
Custom Soil Resource Report
5
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous areas
in a specific area. They include a description of the soils and miscellaneous areas and
their location on the landscape and tables that show soil properties and limitations
affecting various uses. Soil scientists observed the steepness, length, and shape of
the slopes; the general pattern of drainage; the kinds of crops and native plants; and
the kinds of bedrock. They observed and described many soil profiles. A soil profile is
the sequence of natural layers, or horizons, in a soil. The profile extends from the
surface down into the unconsolidated material in which the soil formed or from the
surface down to bedrock. The unconsolidated material is devoid of roots and other
living organisms and has not been changed by other biological activity.
Currently, soils are mapped according to the boundaries of major land resource areas
(MLRAs). MLRAs are geographically associated land resource units that share
common characteristics related to physiography, geology, climate, water resources,
soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically
consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that is
related to the geology, landforms, relief, climate, and natural vegetation of the area.
Each kind of soil and miscellaneous area is associated with a particular kind of
landform or with a segment of the landform. By observing the soils and miscellaneous
areas in the survey area and relating their position to specific segments of the
landform, a soil scientist develops a concept, or model, of how they were formed. Thus,
during mapping, this model enables the soil scientist to predict with a considerable
degree of accuracy the kind of soil or miscellaneous area at a specific location on the
landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented by
an understanding of the soil-vegetation-landscape relationship, are sufficient to verify
predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them to
identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character of
soil properties and the arrangement of horizons within the profile. After the soil
scientists classified and named the soils in the survey area, they compared the
6
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that have
similar use and management requirements. Each map unit is defined by a unique
combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components of
the map unit. The presence of minor components in a map unit in no way diminishes
the usefulness or accuracy of the data. The delineation of such landforms and
landform segments on the map provides sufficient information for the development of
resource plans. If intensive use of small areas is planned, onsite investigation is
needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape, and
experience of the soil scientist. Observations are made to test and refine the soil-
landscape model and predictions and to verify the classification of the soils at specific
locations. Once the soil-landscape model is refined, a significantly smaller number of
measurements of individual soil properties are made and recorded. These
measurements may include field measurements, such as those for color, depth to
bedrock, and texture, and laboratory measurements, such as those for content of
sand, silt, clay, salt, and other components. Properties of each soil typically vary from
one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists interpret
the data from these analyses and tests as well as the field-observed characteristics
and the soil properties to determine the expected behavior of the soils under different
uses. Interpretations for all of the soils are field tested through observation of the soils
in different uses and under different levels of management. Some interpretations are
modified to fit local conditions, and some new interpretations are developed to meet
local needs. Data are assembled from other sources, such as research information,
production records, and field experience of specialists. For example, data on crop
yields under defined levels of management are assembled from farm records and from
field or plot experiments on the same kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on such
variables as climate and biological activity. Soil conditions are predictable over long
periods of time, but they are not predictable from year to year. For example, soil
scientists can predict with a fairly high degree of accuracy that a given soil will have
a high water table within certain depths in most years, but they cannot predict that a
high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
identified each as a specific map unit. Aerial photographs show trees, buildings, fields,
roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of soil
map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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T7S R96W T7S R95W3631
35
2526
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66
34
56
58
34
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34
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67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
43
6
4
0
0
0
43
6
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43
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4
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43
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2
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43
6
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43
6
4
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0
0
43
6
4
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43
6
4
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43
6
4
8
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5
0
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0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters±
39° 24' 3''
10
8
°
2
'
3
9
'
'
39° 23' 14''
10
8
°
2
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4
1
'
'
39° 23' 16''
39° 24' 6''
10
8
°
4
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1
7
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10
8
°
4
'
1
5
'
'
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Soil Map
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Gully
Short Steep Slope
Other
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Map Unit Legend
Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent slopes 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop complex,
steep
125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the landscape,
however, the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They generally
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each. A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
Custom Soil Resource Report
11
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps. The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
12
Rifle Area, Colorado, Parts of Garfield and Mesa Counties
34—Ildefonso stony loam, 25 to 45 percent slopes
Map Unit Setting
Elevation:5,000 to 6,500 feet
Map Unit Composition
Ildefonso and similar soils:90 percent
Description of Ildefonso
Setting
Landform:Alluvial fans, valley sides, breaks
Down-slope shape:Linear, convex
Across-slope shape:Linear, convex
Parent material:Mixed alluvium derived from basalt
Properties and qualities
Slope:25 to 45 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 6.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:35 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 4.0 mmhos/cm)
Available water capacity:Low (about 5.1 inches)
Interpretive groups
Land capability (nonirrigated):7e
Typical profile
0 to 8 inches:Stony loam
8 to 60 inches:Very stony loam
56—Potts loam, 6 to 12 percent slopes
Map Unit Setting
Elevation:5,000 to 7,000 feet
Map Unit Composition
Potts and similar soils:85 percent
Description of Potts
Setting
Landform:Valley sides, benches, mesas
Down-slope shape:Convex, linear
Across-slope shape:Convex, linear
Custom Soil Resource Report
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Parent material:Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Properties and qualities
Slope:6 to 12 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to
0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:High (about 10.3 inches)
Interpretive groups
Land capability classification (irrigated):4e
Land capability (nonirrigated):4e
Ecological site:Rolling Loam (R048AY298CO)
Typical profile
0 to 4 inches:Loam
4 to 28 inches:Clay loam
28 to 60 inches:Loam
58—Potts-Ildefonso complex, 12 to 25 percent slopes
Map Unit Setting
Elevation:5,000 to 6,500 feet
Map Unit Composition
Potts and similar soils:60 percent
Ildefonso and similar soils:30 percent
Description of Potts
Setting
Landform:Valley sides, alluvial fans, mesas
Down-slope shape:Convex, linear
Across-slope shape:Convex, linear
Parent material:Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Properties and qualities
Slope:12 to 25 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to
0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Custom Soil Resource Report
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Calcium carbonate, maximum content:15 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:High (about 10.3 inches)
Interpretive groups
Land capability (nonirrigated):6e
Ecological site:Rolling Loam (R048AY298CO)
Typical profile
0 to 4 inches:Loam
4 to 28 inches:Clay loam
28 to 60 inches:Loam
Description of Ildefonso
Setting
Landform:Alluvial fans, mesas, valley sides
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Properties and qualities
Slope:12 to 25 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 6.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:35 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 4.0 mmhos/cm)
Available water capacity:Low (about 5.1 inches)
Interpretive groups
Land capability (nonirrigated):6e
Typical profile
0 to 8 inches:Stony loam
8 to 60 inches:Very stony loam
66—Torriorthents-Camborthids-Rock outcrop complex, steep
Map Unit Setting
Elevation:5,000 to 8,500 feet
Mean annual precipitation:10 to 15 inches
Mean annual air temperature:39 to 46 degrees F
Frost-free period:80 to 105 days
Map Unit Composition
Torriorthents, steep, and similar soils:45 percent
Custom Soil Resource Report
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Camborthids, steep, and similar soils:20 percent
Rock outcrop, steep:15 percent
Description of Torriorthents, Steep
Setting
Landform:Mountainsides
Landform position (two-dimensional):Footslope
Landform position (three-dimensional):Mountainflank, base slope
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Stony, basaltic alluvium derived from sandstone and shale
Properties and qualities
Slope:15 to 70 percent
Depth to restrictive feature:4 to 30 inches to lithic bedrock
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:Very low (about 2.4 inches)
Interpretive groups
Land capability (nonirrigated):7e
Typical profile
0 to 4 inches:Variable
4 to 30 inches:Fine sandy loam
30 to 34 inches:Unweathered bedrock
Description of Camborthids, Steep
Setting
Landform:Mountainsides
Landform position (two-dimensional):Footslope
Landform position (three-dimensional):Mountainflank, base slope
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Stony, basaltic alluvium derived from sandstone and shale
Properties and qualities
Slope:15 to 65 percent
Depth to restrictive feature:15 to 60 inches to lithic bedrock
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Gypsum, maximum content:2 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:Low (about 4.0 inches)
Custom Soil Resource Report
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Interpretive groups
Land capability (nonirrigated):7e
Typical profile
0 to 4 inches:Variable
4 to 30 inches:Clay loam
30 to 34 inches:Unweathered bedrock
Description of Rock Outcrop, Steep
Setting
Landform:Mountainsides
Landform position (three-dimensional):Free face
Down-slope shape:Convex
Across-slope shape:Convex
Properties and qualities
Slope:15 to 70 percent
Depth to restrictive feature:0 inches to paralithic bedrock
Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately
high (0.00 to 0.20 in/hr)
Available water capacity:Very low (about 0.0 inches)
Interpretive groups
Land capability (nonirrigated):8s
Typical profile
0 to 60 inches:Unweathered bedrock
67—Torriorthents-Rock outcrop complex, steep
Map Unit Setting
Elevation:5,800 to 8,500 feet
Mean annual precipitation:10 to 15 inches
Mean annual air temperature:39 to 46 degrees F
Frost-free period:80 to 105 days
Map Unit Composition
Torriorthents, steep, and similar soils:60 percent
Rock outcrop, steep:25 percent
Description of Torriorthents, Steep
Setting
Landform:Mountainsides
Landform position (two-dimensional):Footslope
Landform position (three-dimensional):Mountainflank, base slope
Down-slope shape:Concave, convex
Across-slope shape:Concave, convex
Parent material:Stony, basaltic alluvium derived from sandstone and shale
Custom Soil Resource Report
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Properties and qualities
Slope:15 to 70 percent
Depth to restrictive feature:4 to 30 inches to lithic bedrock
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:Very low (about 2.4 inches)
Interpretive groups
Land capability (nonirrigated):7e
Typical profile
0 to 4 inches:Variable
4 to 30 inches:Fine sandy loam
30 to 34 inches:Unweathered bedrock
Description of Rock Outcrop, Steep
Setting
Landform:Mountainsides
Landform position (three-dimensional):Free face
Down-slope shape:Convex
Across-slope shape:Convex
Properties and qualities
Slope:15 to 70 percent
Depth to restrictive feature:0 inches to paralithic bedrock
Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately
high (0.00 to 0.20 in/hr)
Available water capacity:Very low (about 0.0 inches)
Interpretive groups
Land capability (nonirrigated):8s
Typical profile
0 to 60 inches:Unweathered bedrock
Custom Soil Resource Report
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Soil Information for All Uses
Suitabilities and Limitations for Use
The Suitabilities and Limitations for Use section includes various soil interpretations
displayed as thematic maps with a summary table for the soil map units in the selected
area of interest. A single value or rating for each map unit is generated by aggregating
the interpretive ratings of individual map unit components. This aggregation process
is defined for each interpretation.
Building Site Development
Building site development interpretations are designed to be used as tools for
evaluating soil suitability and identifying soil limitations for various construction
purposes. As part of the interpretation process, the rating applies to each soil in its
described condition and does not consider present land use. Example interpretations
can include corrosion of concrete and steel, shallow excavations, dwellings with and
without basements, small commercial buildings, local roads and streets, and lawns
and landscaping.
Corrosion of Concrete
"Risk of corrosion" pertains to potential soil-induced electrochemical or chemical
action that corrodes or weakens concrete. The rate of corrosion of concrete is based
mainly on the sulfate and sodium content, texture, moisture content, and acidity of the
soil. Special site examination and design may be needed if the combination of factors
results in a severe hazard of corrosion. The concrete in installations that intersect soil
boundaries or soil layers is more susceptible to corrosion than the concrete in
installations that are entirely within one kind of soil or within one soil layer.
The risk of corrosion is expressed as "low," "moderate," or "high."
19
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
High
Moderate
Low
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Corrosion of Concrete
Corrosion of Concrete— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes Low 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes High 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
High 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
Low 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep Low 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Corrosion of Concrete
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Corrosion of Steel
"Risk of corrosion" pertains to potential soil-induced electrochemical or chemical
action that corrodes or weakens uncoated steel. The rate of corrosion of uncoated
steel is related to such factors as soil moisture, particle-size distribution, acidity, and
electrical conductivity of the soil. Special site examination and design may be needed
if the combination of factors results in a severe hazard of corrosion. The steel in
installations that intersect soil boundaries or soil layers is more susceptible to
corrosion than the steel in installations that are entirely within one kind of soil or within
one soil layer.
The risk of corrosion is expressed as "low," "moderate," or "high."
Custom Soil Resource Report
22
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
High
Moderate
Low
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Corrosion of Steel
Corrosion of Steel— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent
slopes
Moderate 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes High 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
High 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
High 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep High 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Corrosion of Steel
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Local Roads and Streets
Local roads and streets have an all-weather surface and carry automobile and light
truck traffic all year. They have a subgrade of cut or fill soil material; a base of gravel,
crushed rock, or soil material stabilized by lime or cement; and a surface of flexible
material (asphalt), rigid material (concrete), or gravel with a binder. The ratings are
based on the soil properties that affect the ease of excavation and grading and the
traffic-supporting capacity. The properties that affect the ease of excavation and
grading are depth to bedrock or a cemented pan, hardness of bedrock or a cemented
pan, depth to a water table, ponding, flooding, the amount of large stones, and slope.
The properties that affect the traffic-supporting capacity are soil strength (as inferred
from the AASHTO group index number), subsidence, linear extensibility (shrink-swell
potential), the potential for frost action, depth to a water table, and ponding.
The ratings are both verbal and numerical. Rating class terms indicate the extent to
which the soils are limited by all of the soil features that affect the specified use. "Not
limited" indicates that the soil has features that are very favorable for the specified
use. Good performance and very low maintenance can be expected. "Somewhat
limited" indicates that the soil has features that are moderately favorable for the
specified use. The limitations can be overcome or minimized by special planning,
design, or installation. Fair performance and moderate maintenance can be expected.
"Very limited" indicates that the soil has one or more features that are unfavorable for
the specified use. The limitations generally cannot be overcome without major soil
reclamation, special design, or expensive installation procedures. Poor performance
and high maintenance can be expected.
Custom Soil Resource Report
25
Numerical ratings indicate the severity of individual limitations. The ratings are shown
as decimal fractions ranging from 0.01 to 1.00. They indicate gradations between the
point at which a soil feature has the greatest negative impact on the use (1.00) and
the point at which the soil feature is not a limitation (0.00).
The map unit components listed for each map unit in the accompanying Summary by
Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer are
determined by the aggregation method chosen. An aggregated rating class is shown
for each map unit. The components listed for each map unit are only those that have
the same rating class as listed for the map unit. The percent composition of each
component in a particular map unit is presented to help the user better understand the
percentage of each map unit that has the rating presented.
Other components with different ratings may be present in each map unit. The ratings
for all components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil Survey or from
the Soil Data Mart site. Onsite investigation may be needed to validate these
interpretations and to confirm the identity of the soil on a given site.
Custom Soil Resource Report
26
T7S R96W T7S R95W3631
35
2526
R
i
c
h
a
r
d
s
o
n
R
d
66
34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Local Roads and Streets
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Very limited
Somewhat limited
Not limited
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Tables—Local Roads and Streets
Local Roads and Streets— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit
symbol
Map unit name Rating Component name (percent)Rating reasons
(numeric
values)
Acres in
AOI
Percent of
AOI
34 Ildefonso stony loam, 25 to
45 percent slopes
Very limited Ildefonso (90%)Slope (1.00)164.8 34.4%
Large stones
content (1.00)
56 Potts loam, 6 to 12 percent
slopes
Very limited Potts (85%)Low strength
(1.00)
68.5 14.3%
Shrink-swell
(0.50)
Slope (0.04)
58 Potts-Ildefonso complex, 12
to 25 percent slopes
Very limited Potts (60%)Slope (1.00)109.8 22.9%
Low strength
(1.00)
Shrink-swell
(0.50)
Ildefonso (30%)Slope (1.00)
Large stones
content (1.00)
66 Torriorthents-Camborthids-
Rock outcrop complex,
steep
Very limited Torriorthents, steep (45%)Depth to hard
bedrock
(1.00)
125.1 26.1%
Slope (1.00)
Camborthids, steep (20%)Slope (1.00)
Shrink-swell
(0.50)
Low strength
(0.22)
Depth to hard
bedrock
(0.02)
67 Torriorthents-Rock outcrop
complex, steep
Very limited Torriorthents, steep (60%)Depth to hard
bedrock
(1.00)
10.3 2.1%
Slope (1.00)
Totals for Area of Interest 478.6 100.0%
Local Roads and Streets— Summary by Rating Value
Rating Acres in AOI Percent of AOI
Very limited 478.6 100.0%
Totals for Area of Interest 478.6 100.0%
Custom Soil Resource Report
29
Rating Options—Local Roads and Streets
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Construction Materials
Construction materials interpretations are tools designed to provide guidance to users
in selecting a site for potential source of various materials. Individual soils or groups
of soils may be selected as a potential source because they are close at hand, are the
only source available, or they meets some or all of the physical or chemical properties
required for the intended application. Example interpretations include roadfill, sand
and gravel, topsoil and reclamation material.
Sand Source
Sand is a natural aggregate (0.05 millimeter to 2 millimeters in diameter) suitable for
commercial use with a minimum of processing. It is used in many kinds of construction.
Specifications for each use vary widely. Only the probability of finding material in
suitable quantity is evaluated. The suitability of the material for specific purposes is
not evaluated, nor are factors that affect excavation of the material.
The properties used to evaluate the soil as a source of sand are gradation of grain
sizes (as indicated by the Unified classification of the soil), the thickness of suitable
material, and the content of rock fragments. If the bottom layer of the soil contains
sand, the soil is considered a likely source regardless of thickness. The assumption
is that the sand layer below the depth of observation exceeds the minimum thickness.
The ratings are for the whole soil, from the surface to a depth of about 6 feet.
The soils are rated "good," "fair," or "poor" as potential sources of sand. A rating of
"good" or "fair" means that sand is likely to be in or below the soil. The bottom layer
and the thickest layer of the soil are assigned numerical ratings. These ratings indicate
the likelihood that the layer is a source of sand. The number 0.00 indicates that the
layer is a "poor source." The number 1.00 indicates that the layer is a "good source."
A number between 0.00 and 1.00 indicates the degree to which the layer is a likely
source.
The map unit components listed for each map unit in the accompanying Summary by
Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer are
determined by the aggregation method chosen. An aggregated rating class is shown
for each map unit. The components listed for each map unit are only those that have
the same rating class as listed for the map unit. The percent composition of each
component in a particular map unit is presented to help the user better understand the
percentage of each map unit that has the rating presented.
Custom Soil Resource Report
30
Other components with different ratings may be present in each map unit. The ratings
for all components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil Survey or from
the Soil Data Mart site. Onsite investigation may be needed to validate these
interpretations and to confirm the identity of the soil on a given site.
Custom Soil Resource Report
31
T7S R96W T7S R95W3631
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2526
R
i
c
h
a
r
d
s
o
n
R
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66
34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Sand Source
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Poor
Fair
Good
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Tables—Sand Source
Sand Source— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit
symbol
Map unit name Rating Component name (percent)Rating reasons
(numeric
values)
Acres in
AOI
Percent of
AOI
34 Ildefonso stony loam, 25 to
45 percent slopes
Poor Ildefonso (90%)Bottom layer
(0.00)
164.8 34.4%
Thickest layer
(0.00)
56 Potts loam, 6 to 12 percent
slopes
Poor Potts (85%)Bottom layer
(0.00)
68.5 14.3%
Thickest layer
(0.00)
58 Potts-Ildefonso complex, 12
to 25 percent slopes
Poor Potts (60%)Bottom layer
(0.00)
109.8 22.9%
Thickest layer
(0.00)
Ildefonso (30%)Bottom layer
(0.00)
Thickest layer
(0.00)
66 Torriorthents-Camborthids-
Rock outcrop complex,
steep
Poor Torriorthents, steep (45%)Bottom layer
(0.00)
125.1 26.1%
Thickest layer
(0.00)
Camborthids, steep (20%)Bottom layer
(0.00)
Thickest layer
(0.00)
67 Torriorthents-Rock outcrop
complex, steep
Poor Torriorthents, steep (60%)Bottom layer
(0.00)
10.3 2.1%
Thickest layer
(0.00)
Totals for Area of Interest 478.6 100.0%
Sand Source— Summary by Rating Value
Rating Acres in AOI Percent of AOI
Poor 478.6 100.0%
Totals for Area of Interest 478.6 100.0%
Rating Options—Sand Source
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
Custom Soil Resource Report
34
Topsoil Source
Topsoil is used to cover an area so that vegetation can be established and maintained.
The surface layer of most soils is generally preferred for topsoil because of its content
of organic matter. Organic matter greatly increases the absorption and retention of
moisture and nutrients for plant growth.
The upper 40 inches of a soil is evaluated for use as topsoil. Also evaluated is the
reclamation potential of the borrow area. Normal compaction, minor processing, and
other standard construction practices are assumed.
The soils are rated "good," "fair," or "poor" as potential sources of topsoil. The ratings
are based on the soil properties that affect plant growth; the ease of excavating,
loading, and spreading the material; and reclamation of the borrow area. Toxic
substances, soil reaction, and the properties that are inferred from soil texture, such
as available water capacity and fertility, affect plant growth. The ease of excavating,
loading, and spreading is affected by rock fragments, slope, depth to a water table,
soil texture, and thickness of suitable material. Reclamation of the borrow area is
affected by slope, depth to a water table, rock fragments, depth to bedrock or a
cemented pan, and toxic material.
Numerical ratings between 0.00 and 0.99 are given after the specified features. These
numbers indicate the degree to which the features limit the soils as sources of topsoil.
The lower the number, the greater the limitation.
The map unit components listed for each map unit in the accompanying Summary by
Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer are
determined by the aggregation method chosen. An aggregated rating class is shown
for each map unit. The components listed for each map unit are only those that have
the same rating class as listed for the map unit. The percent composition of each
component in a particular map unit is presented to help the user better understand the
percentage of each map unit that has the rating presented.
Other components with different ratings may be present in each map unit. The ratings
for all components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil Survey or from
the Soil Data Mart site. Onsite investigation may be needed to validate these
interpretations and to confirm the identity of the soil on a given site.
Custom Soil Resource Report
35
T7S R96W T7S R95W3631
35
2526
R
i
c
h
a
r
d
s
o
n
R
d
66
34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Topsoil Source
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Poor
Fair
Good
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Tables—Topsoil Source
Topsoil Source— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit
symbol
Map unit name Rating Component name (percent)Rating reasons
(numeric values)
Acres in
AOI
Percent of
AOI
34 Ildefonso stony loam, 25 to
45 percent slopes
Poor Ildefonso (90%)Slope (0.00)164.8 34.4%
Rock fragments
(0.00)
Hard to reclaim (rock
fragments) (0.00)
Carbonate content
(0.84)
56 Potts loam, 6 to 12 percent
slopes
Fair Potts (85%)Too clayey (0.72)68.5 14.3%
Slope (0.96)
58 Potts-Ildefonso complex,
12 to 25 percent slopes
Poor Potts (60%)Slope (0.00)109.8 22.9%
Too clayey (0.72)
Ildefonso (30%)Slope (0.00)
Rock fragments
(0.00)
Hard to reclaim (rock
fragments) (0.00)
Carbonate content
(0.84)
66 Torriorthents-Camborthids-
Rock outcrop complex,
steep
Poor Torriorthents, steep (45%)Slope (0.00)125.1 26.1%
Depth to bedrock
(0.00)
Rock fragments
(0.88)
Camborthids, steep (20%)Slope (0.00)
Rock fragments
(0.97)
Depth to bedrock
(0.98)
67 Torriorthents-Rock outcrop
complex, steep
Poor Torriorthents, steep (60%)Slope (0.00)10.3 2.1%
Depth to bedrock
(0.00)
Rock fragments
(0.98)
Totals for Area of Interest 478.6 100.0%
Topsoil Source— Summary by Rating Value
Rating Acres in AOI Percent of AOI
Poor 410.0 85.7%
Fair 68.5 14.3%
Totals for Area of Interest 478.6 100.0%
Custom Soil Resource Report
38
Rating Options—Topsoil Source
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
Land Classifications
Land Classifications are specified land use and management groupings that are
assigned to soil areas because combinations of soil have similar behavior for specified
practices. Most are based on soil properties and other factors that directly influence
the specific use of the soil. Example classifications include ecological site
classification, farmland classification, irrigated and nonirrigated land capability
classification, and hydric rating.
Ecological Site ID: NRCS Rangeland Site
An "ecological site ID" is the symbol assigned to a particular ecological site. An
"ecological site" is the product of all the environmental factors responsible for its
development. It has characteristic soils that have developed over time; a characteristic
hydrology, particularly infiltration and runoff, that has developed over time; and a
characteristic plant community (kind and amount of vegetation). The vegetation, soils,
and hydrology are all interrelated. Each is influenced by the others and influences the
development of the others. For example, the hydrology of the site is influenced by
development of the soil and plant community. The plant community on an ecological
site is typified by an association of species that differs from that of other ecological
sites in the kind and/or proportion of species or in total production. Descriptions of
ecological sites are provided in the Field Office Technical Guide, which is available in
local offices of the Natural Resources Conservation Service.
Custom Soil Resource Report
39
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
R048AY298CO
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Ecological Site ID: NRCS Rangeland Site
Ecological Site ID: NRCS Rangeland Site— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties
(CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent
slopes
164.8 34.4%
56 Potts loam, 6 to 12 percent slopes R048AY298CO 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25
percent slopes
R048AY298CO 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
125.1 26.1%
67 Torriorthents-Rock outcrop complex,
steep
10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Ecological Site ID: NRCS Rangeland Site
Class: NRCS Rangeland Site
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
Land Management
Land management interpretations are tools designed to guide the user in evaluating
existing conditions in planning and predicting the soil response to various land
management practices, for a variety of land uses, including cropland, forestland,
hayland, pastureland, horticulture, and rangeland. Example interpretations include
suitability for a variety of irrigation practices, log landings, haul roads and major skid
trails, equipment operability, site preparation, suitability for hand and mechanical
planting, potential erosion hazard associated with various practices, and ratings for
fencing and waterline installation.
Mechanical Site Preparation (Surface)
The ratings in this interpretation indicate the suitability for use of surface-altering soil
tillage equipment during site preparation in forested areas. The ratings are based on
slope, depth to a restrictive layer, plasticity index, rock fragments on or below the
surface, depth to a water table, and ponding. The part of the soil from the surface to
a depth of about 1 foot is considered in the ratings.
The ratings are both verbal and numerical. Rating class terms indicate the degree to
which the soils are suited to this aspect of forestland management. The soils are
Custom Soil Resource Report
42
described as "well suited," "poorly suited," or "unsuited" to this management activity.
"Well suited" indicates that the soil has features that are favorable for the specified
kind of site preparation and has no limitations. Good performance can be expected,
and little or no maintenance is needed. "Poorly suited" indicates that the soil has one
or more properties that are unfavorable for the specified kind of site preparation.
Overcoming the unfavorable properties requires special design, extra maintenance,
and costly alteration. "Unsuited" indicates that the expected performance of the soil
is unacceptable for the specified kind of site preparation or that extreme measures
are needed to overcome the undesirable soil properties.
Numerical ratings indicate the severity of individual limitations. The ratings are shown
as decimal fractions ranging from 0.01 to 1.00. They indicate gradations between the
point at which a soil feature has the greatest negative impact on the specified aspect
of forestland management (1.00) and the point at which the soil feature is not a
limitation (0.00).
The map unit components listed for each map unit in the accompanying Summary by
Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer are
determined by the aggregation method chosen. An aggregated rating class is shown
for each map unit. The components listed for each map unit are only those that have
the same rating class as listed for the map unit. The percent composition of each
component in a particular map unit is presented to help the user better understand the
percentage of each map unit that has the rating presented.
Other components with different ratings may be present in each map unit. The ratings
for all components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil Survey or from
the Soil Data Mart site. Onsite investigation may be needed to validate these
interpretations and to confirm the identity of the soil on a given site.
Custom Soil Resource Report
43
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Unsuited
Poorly suited
Well suited
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Tables—Mechanical Site Preparation (Surface)
Mechanical Site Preparation (Surface)— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties
(CO683)
Map unit
symbol
Map unit name Rating Component name (percent)Rating reasons
(numeric values)
Acres in
AOI
Percent of
AOI
34 Ildefonso stony loam, 25 to
45 percent slopes
Poorly suited Ildefonso (90%)Slope (0.50)164.8 34.4%
Rock fragments
(0.50)
56 Potts loam, 6 to 12 percent
slopes
Well suited Potts (85%)68.5 14.3%
58 Potts-Ildefonso complex,
12 to 25 percent slopes
Poorly suited Potts (60%)Slope (0.50)109.8 22.9%
Ildefonso (30%)Slope (0.50)
Rock fragments
(0.50)
66 Torriorthents-
Camborthids-Rock
outcrop complex, steep
Unsuited Torriorthents, steep (45%)Slope (1.00)125.1 26.1%
Camborthids, steep (20%)Slope (1.00)
Rock outcrop, steep (15%)Slope (1.00)
67 Torriorthents-Rock outcrop
complex, steep
Unsuited Torriorthents, steep (60%)Slope (1.00)10.3 2.1%
Rock outcrop, steep (25%)Slope (1.00)
Totals for Area of Interest 478.6 100.0%
Mechanical Site Preparation (Surface)— Summary by Rating Value
Rating Acres in AOI Percent of AOI
Poorly suited 274.6 57.4%
Unsuited 135.4 28.3%
Well suited 68.5 14.3%
Totals for Area of Interest 478.6 100.0%
Rating Options—Mechanical Site Preparation (Surface)
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Water Management
Water Management interpretations are tools for evaluating the potential of the soil in
the application of various water management practices. Example interpretations
include pond reservoir area, embankments, dikes, levees, and excavated ponds.
Custom Soil Resource Report
46
Pond Reservoir Areas
Pond reservoir areas hold water behind a dam or embankment. Soils best suited to
this use have low seepage potential in the upper 60 inches. The seepage potential is
determined by the saturated hydraulic conductivity (Ksat) of the soil and the depth to
fractured bedrock or other permeable material. Excessive slope can affect the storage
capacity of the reservoir area.
The ratings are both verbal and numerical. Rating class terms indicate the extent to
which the soils are limited by all of the soil features that affect the specified use. "Not
limited" indicates that the soil has features that are very favorable for the specified
use. Good performance and very low maintenance can be expected. "Somewhat
limited" indicates that the soil has features that are moderately favorable for the
specified use. The limitations can be overcome or minimized by special planning,
design, or installation. Fair performance and moderate maintenance can be expected.
"Very limited" indicates that the soil has one or more features that are unfavorable for
the specified use. The limitations generally cannot be overcome without major soil
reclamation, special design, or expensive installation procedures. Poor performance
and high maintenance can be expected.
Numerical ratings indicate the severity of individual limitations. The ratings are shown
as decimal fractions ranging from 0.01 to 1.00. They indicate gradations between the
point at which a soil feature has the greatest negative impact on the use (1.00) and
the point at which the soil feature is not a limitation (0.00).
The map unit components listed for each map unit in the accompanying Summary by
Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer are
determined by the aggregation method chosen. An aggregated rating class is shown
for each map unit. The components listed for each map unit are only those that have
the same rating class as listed for the map unit. The percent composition of each
component in a particular map unit is presented to help the user better understand the
percentage of each map unit that has the rating presented.
Other components with different ratings may be present in each map unit. The ratings
for all components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil Survey or from
the Soil Data Mart site. Onsite investigation may be needed to validate these
interpretations and to confirm the identity of the soil on a given site.
Custom Soil Resource Report
47
T7S R96W T7S R95W3631
35
2526
R
i
c
h
a
r
d
s
o
n
R
d
66
34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Pond Reservoir Areas
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Very limited
Somewhat limited
Not limited
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Tables—Pond Reservoir Areas
Pond Reservoir Areas— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit
symbol
Map unit name Rating Component name (percent)Rating reasons
(numeric
values)
Acres in
AOI
Percent of
AOI
34 Ildefonso stony loam, 25 to
45 percent slopes
Very limited Ildefonso (90%)Slope (1.00)164.8 34.4%
Seepage (1.00)
56 Potts loam, 6 to 12 percent
slopes
Very limited Potts (85%)Slope (1.00)68.5 14.3%
Seepage (1.00)
58 Potts-Ildefonso complex, 12
to 25 percent slopes
Very limited Potts (60%)Slope (1.00)109.8 22.9%
Seepage (1.00)
Ildefonso (30%)Slope (1.00)
Seepage (1.00)
66 Torriorthents-Camborthids-
Rock outcrop complex,
steep
Very limited Torriorthents, steep (45%)Slope (1.00)125.1 26.1%
Depth to
bedrock
(1.00)
Seepage (0.72)
Camborthids, steep (20%)Slope (1.00)
Seepage (0.72)
Depth to
bedrock
(0.59)
Rock outcrop, steep (15%)Slope (1.00)
Depth to
bedrock
(1.00)
67 Torriorthents-Rock outcrop
complex, steep
Very limited Torriorthents, steep (60%)Slope (1.00)10.3 2.1%
Depth to
bedrock
(1.00)
Seepage (0.72)
Rock outcrop, steep (25%)Slope (1.00)
Depth to
bedrock
(1.00)
Totals for Area of Interest 478.6 100.0%
Pond Reservoir Areas— Summary by Rating Value
Rating Acres in AOI Percent of AOI
Very limited 478.6 100.0%
Totals for Area of Interest 478.6 100.0%
Custom Soil Resource Report
50
Rating Options—Pond Reservoir Areas
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Excavated Ponds (Aquifer-Fed)
Excavated ponds (aquifer-fed) are pits or dugouts that extend to a ground-water
aquifer or to a depth below a permanent water table. Excluded are ponds that are fed
only by surface runoff and embankment ponds that impound water 3 feet or more
above the original surface. Excavated ponds are affected by depth to a permanent
water table, saturated hydraulic conductivity (Ksat) of the aquifer, and quality of the
water as inferred from the salinity of the soil. Depth to bedrock and the content of large
stones affect the ease of excavation.
The ratings are both verbal and numerical. Rating class terms indicate the extent to
which the soils are limited by all of the soil features that affect the specified use. "Not
limited" indicates that the soil has features that are very favorable for the specified
use. Good performance and very low maintenance can be expected. "Somewhat
limited" indicates that the soil has features that are moderately favorable for the
specified use. The limitations can be overcome or minimized by special planning,
design, or installation. Fair performance and moderate maintenance can be expected.
"Very limited" indicates that the soil has one or more features that are unfavorable for
the specified use. The limitations generally cannot be overcome without major soil
reclamation, special design, or expensive installation procedures. Poor performance
and high maintenance can be expected.
Numerical ratings indicate the severity of individual limitations. The ratings are shown
as decimal fractions ranging from 0.01 to 1.00. They indicate gradations between the
point at which a soil feature has the greatest negative impact on the use (1.00) and
the point at which the soil feature is not a limitation (0.00).
The map unit components listed for each map unit in the accompanying Summary by
Map Unit table in Web Soil Survey or the Aggregation Report in Soil Data Viewer are
determined by the aggregation method chosen. An aggregated rating class is shown
for each map unit. The components listed for each map unit are only those that have
the same rating class as listed for the map unit. The percent composition of each
component in a particular map unit is presented to help the user better understand the
percentage of each map unit that has the rating presented.
Other components with different ratings may be present in each map unit. The ratings
for all components, regardless of the map unit aggregated rating, can be viewed by
generating the equivalent report from the Soil Reports tab in Web Soil Survey or from
the Soil Data Mart site. Onsite investigation may be needed to validate these
interpretations and to confirm the identity of the soil on a given site.
Custom Soil Resource Report
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T7S R96W T7S R95W3631
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34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Excavated Ponds (Aquifer-Fed)
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Very limited
Somewhat limited
Not limited
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Tables—Excavated Ponds (Aquifer-Fed)
Excavated Ponds (Aquifer-Fed)— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit
symbol
Map unit name Rating Component name (percent)Rating reasons
(numeric
values)
Acres in
AOI
Percent of
AOI
34 Ildefonso stony loam, 25 to
45 percent slopes
Very limited Ildefonso (90%)Depth to water
(1.00)
164.8 34.4%
56 Potts loam, 6 to 12 percent
slopes
Very limited Potts (85%)Depth to water
(1.00)
68.5 14.3%
58 Potts-Ildefonso complex, 12
to 25 percent slopes
Very limited Potts (60%)Depth to water
(1.00)
109.8 22.9%
Ildefonso (30%)Depth to water
(1.00)
66 Torriorthents-Camborthids-
Rock outcrop complex,
steep
Very limited Torriorthents, steep (45%)Depth to water
(1.00)
125.1 26.1%
Camborthids, steep (20%)Depth to water
(1.00)
67 Torriorthents-Rock outcrop
complex, steep
Very limited Torriorthents, steep (60%)Depth to water
(1.00)
10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Excavated Ponds (Aquifer-Fed)— Summary by Rating Value
Rating Acres in AOI Percent of AOI
Very limited 478.6 100.0%
Totals for Area of Interest 478.6 100.0%
Rating Options—Excavated Ponds (Aquifer-Fed)
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Custom Soil Resource Report
54
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and qualities
displayed as thematic maps with a summary table for the soil map units in the selected
area of interest. A single value or rating for each map unit is generated by aggregating
the interpretive ratings of individual map unit components. This aggregation process
is defined for each property or quality.
Soil Qualities and Features
Soil qualities are behavior and performance attributes that are not directly measured,
but are inferred from observations of dynamic conditions and from soil properties.
Example soil qualities include natural drainage, and frost action. Soil features are
attributes that are not directly part of the soil. Example soil features include slope and
depth to restrictive layer. These features can greatly impact the use and management
of the soil.
Depth to Any Soil Restrictive Layer
A "restrictive layer" is a nearly continuous layer that has one or more physical,
chemical, or thermal properties that significantly impede the movement of water and
air through the soil or that restrict roots or otherwise provide an unfavorable root
environment. Examples are bedrock, cemented layers, dense layers, and frozen
layers.
This theme presents the depth to any type of restrictive layer that is described for each
map unit. If more than one type of restrictive layer is described for an individual soil
type, the depth to the shallowest one is presented. If no restrictive layer is described
in a map unit, it is represented by the "> 200" depth class.
This attribute is actually recorded as three separate values in the database. A low
value and a high value indicate the range of this attribute for the soil component. A
"representative" value indicates the expected value of this attribute for the component.
For this soil property, only the representative value is used.
Custom Soil Resource Report
55
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34
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752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Depth to Any Soil Restrictive Layer
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
0 - 25
25 - 50
50 - 100
100 - 150
150 - 200
> 200
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Depth to Any Soil Restrictive Layer
Depth to Any Soil Restrictive Layer— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties
(CO683)
Map unit
symbol
Map unit name Rating (centimeters)Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent
slopes
>200 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes >200 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25
percent slopes
>200 109.8 22.9%
66 Torriorthents-Camborthids-Rock
outcrop complex, steep
43 125.1 26.1%
67 Torriorthents-Rock outcrop complex,
steep
43 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Depth to Any Soil Restrictive Layer
Units of Measure: centimeters
Aggregation Method: Dominant Component
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
Interpret Nulls as Zero: No
Drainage Class
"Drainage class (natural)" refers to the frequency and duration of wet periods under
conditions similar to those under which the soil formed. Alterations of the water regime
by human activities, either through drainage or irrigation, are not a consideration
unless they have significantly changed the morphology of the soil. Seven classes of
natural soil drainage are recognized-excessively drained, somewhat excessively
drained, well drained, moderately well drained, somewhat poorly drained, poorly
drained, and very poorly drained. These classes are defined in the "Soil Survey
Manual."
Custom Soil Resource Report
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58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Drainage Class
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
Excessively drained
Somewhat excessively
drained
Well drained
Moderately well drained
Somewhat poorly drained
Poorly drained
Very poorly drained
Subaqueous
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Drainage Class
Drainage Class— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes Well drained 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes Well drained 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
Well drained 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
Well drained 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep Well drained 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Drainage Class
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group
Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned
to one of four groups according to the rate of water infiltration when the soils are not
protected by vegetation, are thoroughly wet, and receive precipitation from long-
duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and three
dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist
chiefly of moderately deep or deep, moderately well drained or well drained soils that
have moderately fine texture to moderately coarse texture. These soils have a
moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or soils
of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Custom Soil Resource Report
61
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential,
soils that have a high water table, soils that have a claypan or clay layer at or near the
surface, and soils that are shallow over nearly impervious material. These soils have
a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for
drained areas and the second is for undrained areas. Only the soils that in their natural
condition are in group D are assigned to dual classes.
Custom Soil Resource Report
62
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes B 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes B 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
B 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
D 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep D 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Hydrologic Soil Group
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Representative Slope
Slope gradient is the difference in elevation between two points, expressed as a
percentage of the distance between those points.
The slope gradient is actually recorded as three separate values in the database. A
low value and a high value indicate the range of this attribute for the soil component.
A "representative" value indicates the expected value of this attribute for the
component. For this soil property, only the representative value is used.
Custom Soil Resource Report
65
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
0 - 5
5 - 15
15 - 30
30 - 45
45 - 60
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Representative Slope
Representative Slope— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating (percent)Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent
slopes
35.0 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes 9.0 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
19.0 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
43.0 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep 43.0 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Representative Slope
Units of Measure: percent
Aggregation Method: Dominant Component
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Interpret Nulls as Zero: No
Unified Soil Classification (Surface)
The Unified soil classification system classifies mineral and organic mineral soils for
engineering purposes on the basis of particle-size characteristics, liquid limit, and
plasticity index. It identifies three major soil divisions: (i) coarse-grained soils having
less than 50 percent, by weight, particles smaller than 0.074 mm in diameter; (ii) fine-
grained soils having 50 percent or more, by weight, particles smaller than 0.074 mm
in diameter; and (iii) highly organic soils that demonstrate certain organic
characteristics. These divisions are further subdivided into a total of 15 basic soil
groups. The major soil divisions and basic soil groups are determined on the basis of
estimated or measured values for grain-size distribution and Atterberg limits. ASTM
D 2487 shows the criteria chart used for classifying soil in the Unified system and the
15 basic soil groups of the system and the plasticity chart for the Unified system.
The various groupings of this classification correlate in a general way with the
engineering behavior of soils. This correlation provides a useful first step in any field
or laboratory investigation for engineering purposes. It can serve to make some
general interpretations relating to probable performance of the soil for engineering
uses.
For each soil horizon in the database one or more Unified soil classifications may be
listed. One is marked as the representative or most commonly occurring. The
representative classification is shown here for the surface layer of the soil.
Custom Soil Resource Report
68
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
CH
CL
CL-A (proposed)
CL-K (proposed)
CL-ML
CL-O (proposed)
CL-T (proposed)
GC
GC-GM
GM
GP
GP-GC
GP-GM
GW
GW-GC
GW-GM
MH
MH-A (proposed)
MH-K (proposed)
MH-O (proposed)
MH-T (proposed)
ML
ML-A (proposed)
ML-K (proposed)
ML-O (proposed)
ML-T (proposed)
OH
OH-T (proposed)
OL
PT
SC
SC-SM
SM
SP
SP-SC
SP-SM
SW
SW-SC
SW-SM
Not rated or not available
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Unified Soil Classification (Surface)
Unified Soil Classification (Surface)— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties
(CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes CL 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes CL 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
CL 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Unified Soil Classification (Surface)
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
Layer Options: Surface Layer
Water Features
Water Features include ponding frequency, flooding frequency, and depth to water
table.
Flooding Frequency Class
Flooding is the temporary inundation of an area caused by overflowing streams, by
runoff from adjacent slopes, or by tides. Water standing for short periods after rainfall
or snowmelt is not considered flooding, and water standing in swamps and marshes
is considered ponding rather than flooding.
Frequency is expressed as none, very rare, rare, occasional, frequent, and very
frequent.
"None" means that flooding is not probable. The chance of flooding is nearly 0 percent
in any year. Flooding occurs less than once in 500 years.
"Very rare" means that flooding is very unlikely but possible under extremely unusual
weather conditions. The chance of flooding is less than 1 percent in any year.
Custom Soil Resource Report
71
"Rare" means that flooding is unlikely but possible under unusual weather conditions.
The chance of flooding is 1 to 5 percent in any year.
"Occasional" means that flooding occurs infrequently under normal weather
conditions. The chance of flooding is 5 to 50 percent in any year.
"Frequent" means that flooding is likely to occur often under normal weather
conditions. The chance of flooding is more than 50 percent in any year but is less than
50 percent in all months in any year.
"Very frequent" means that flooding is likely to occur very often under normal weather
conditions. The chance of flooding is more than 50 percent in all months of any year.
Custom Soil Resource Report
72
T7S R96W T7S R95W3631
35
2526
R
i
c
h
a
r
d
s
o
n
R
d
66
34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Flooding Frequency Class
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
None
Very Rare
Rare
Occasional
Frequent
Very Frequent
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Flooding Frequency Class
Flooding Frequency Class— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes None 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes None 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
None 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
None 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep None 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Flooding Frequency Class
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: More Frequent
Beginning Month: January
Ending Month: December
Ponding Frequency Class
Ponding is standing water in a closed depression. The water is removed only by deep
percolation, transpiration, or evaporation or by a combination of these processes.
Ponding frequency classes are based on the number of times that ponding occurs
over a given period. Frequency is expressed as none, rare, occasional, and frequent.
"None" means that ponding is not probable. The chance of ponding is nearly 0 percent
in any year.
"Rare" means that ponding is unlikely but possible under unusual weather conditions.
The chance of ponding is nearly 0 percent to 5 percent in any year.
"Occasional" means that ponding occurs, on the average, once or less in 2 years. The
chance of ponding is 5 to 50 percent in any year.
"Frequent" means that ponding occurs, on the average, more than once in 2 years.
The chance of ponding is more than 50 percent in any year.
Custom Soil Resource Report
75
T7S R96W T7S R95W3631
35
2526
R
i
c
h
a
r
d
s
o
n
R
d
66
34
56
58
34
58
34
58
67
752400
752400
752600
752600
752800
752800
753000
753000
753200
753200
753400
753400
753600
753600
753800
753800
754000
754000
754200
754200
754400
754400
4 3 6 4
0 0 0
4 3 6 4
0 0 0
4 3 6 4 2 0 0
4 3 6 4 2 0 0
4 3 6 4
4 0 0
4 3 6 4
4 0 0
4 3 6 4 6 0 0
4 3 6 4 6 0 0
4 3 6 4
8 0 0
4 3 6 4
8 0 0
4 3 6 5 0 0 0
4 3 6 5 0 0 0
4 3 6 5
2 0 0
4 3 6 5
2 0 0
4 3 6 5 4 0 0
4 3 6 5 4 0 0
0 1,000 2,000 3,000500
Feet
0 300 600 900150
Meters
39° 24' 3''
1 0 8 ° 2 ' 3 9 ''
39° 23' 14''
1 0 8 ° 2 ' 4 1 ''
39° 23' 16''
39° 24' 6''
1 0 8 ° 4 ' 1 7 ''
1 0 8 ° 4 ' 1 5 ''
Map Scale: 1:11,000 if printed on A size (8.5" x 11") sheet.
Custom Soil Resource Report
Map—Ponding Frequency Class
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
None
Rare
Occasional
Frequent
Political Features
Cities
PLSS Township and
Range
PLSS Section
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:11,000 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 12N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 6, Mar 25, 2008
Date(s) aerial images were photographed: 8/8/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
Table—Ponding Frequency Class
Ponding Frequency Class— Summary by Map Unit — Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45 percent slopes None 164.8 34.4%
56 Potts loam, 6 to 12 percent slopes None 68.5 14.3%
58 Potts-Ildefonso complex, 12 to 25 percent
slopes
None 109.8 22.9%
66 Torriorthents-Camborthids-Rock outcrop
complex, steep
None 125.1 26.1%
67 Torriorthents-Rock outcrop complex, steep None 10.3 2.1%
Totals for Area of Interest 478.6 100.0%
Rating Options—Ponding Frequency Class
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: More Frequent
Beginning Month: January
Ending Month: December
Custom Soil Resource Report
78
Soil Reports
The Soil Reports section includes various formatted tabular and narrative reports
(tables) containing data for each selected soil map unit and each component of each
unit. No aggregation of data has occurred as is done in reports in the Soil Properties
and Qualities and Suitabilities and Limitations sections.
The reports contain soil interpretive information as well as basic soil properties and
qualities. A description of each report (table) is included.
Building Site Development
This folder contains a collection of tabular reports that present soil interpretations
related to building site development. The reports (tables) include all selected map units
and components for each map unit, limiting features and interpretive ratings. Building
site development interpretations are designed to be used as tools for evaluating soil
suitability and identifying soil limitations for various construction purposes. As part of
the interpretation process, the rating applies to each soil in its described condition and
does not consider present land use. Example interpretations can include corrosion of
concrete and steel, shallow excavations, dwellings with and without basements, small
commercial buildings, local roads and streets, and lawns and landscaping.
Roads and Streets, Shallow Excavations, and Lawns and
Landscaping
Soil properties influence the development of building sites, including the selection of
the site, the design of the structure, construction, performance after construction, and
maintenance. This table shows the degree and kind of soil limitations that affect local
roads and streets, shallow excavations, and lawns and landscaping.
The ratings in the table are both verbal and numerical. Rating class terms indicate the
extent to which the soils are limited by all of the soil features that affect building site
development. Not limited indicates that the soil has features that are very favorable
for the specified use. Good performance and very low maintenance can be expected.
Somewhat limited indicates that the soil has features that are moderately favorable
for the specified use. The limitations can be overcome or minimized by special
planning, design, or installation. Fair performance and moderate maintenance can be
expected. Very limited indicates that the soil has one or more features that are
unfavorable for the specified use. The limitations generally cannot be overcome
without major soil reclamation, special design, or expensive installation procedures.
Poor performance and high maintenance can be expected.
Numerical ratings in the table indicate the severity of individual limitations. The ratings
are shown as decimal fractions ranging from 0.01 to 1.00. They indicate gradations
between the point at which a soil feature has the greatest negative impact on the use
(1.00) and the point at which the soil feature is not a limitation (0.00).
Local roads and streets have an all-weather surface and carry automobile and light
truck traffic all year. They have a subgrade of cut or fill soil material; a base of gravel,
Custom Soil Resource Report
79
crushed rock, or soil material stabilized by lime or cement; and a surface of flexible
material (asphalt), rigid material (concrete), or gravel with a binder. The ratings are
based on the soil properties that affect the ease of excavation and grading and the
traffic-supporting capacity. The properties that affect the ease of excavation and
grading are depth to bedrock or a cemented pan, hardness of bedrock or a cemented
pan, depth to a water table, ponding, flooding, the amount of large stones, and slope.
The properties that affect the traffic-supporting capacity are soil strength (as inferred
from the AASHTO group index number), subsidence, linear extensibility (shrink-swell
potential), the potential for frost action, depth to a water table, and ponding.
Shallow excavations are trenches or holes dug to a maximum depth of 5 or 6 feet for
graves, utility lines, open ditches, or other purposes. The ratings are based on the soil
properties that influence the ease of digging and the resistance to sloughing. Depth
to bedrock or a cemented pan, hardness of bedrock or a cemented pan, the amount
of large stones, and dense layers influence the ease of digging, filling, and compacting.
Depth to the seasonal high water table, flooding, and ponding may restrict the period
when excavations can be made. Slope influences the ease of using machinery. Soil
texture, depth to the water table, and linear extensibility (shrink-swell potential)
influence the resistance to sloughing.
Lawns and landscaping require soils on which turf and ornamental trees and shrubs
can be established and maintained. Irrigation is not considered in the ratings. The
ratings are based on the soil properties that affect plant growth and trafficability after
vegetation is established. The properties that affect plant growth are reaction; depth
to a water table; ponding; depth to bedrock or a cemented pan; the available water
capacity in the upper 40 inches; the content of salts, sodium, or calcium carbonate;
and sulfidic materials. The properties that affect trafficability are flooding, depth to a
water table, ponding, slope, stoniness, and the amount of sand, clay, or organic matter
in the surface layer.
Information in this table is intended for land use planning, for evaluating land use
alternatives, and for planning site investigations prior to design and construction. The
information, however, has limitations. For example, estimates and other data generally
apply only to that part of the soil between the surface and a depth of 5 to 7 feet.
Because of the map scale, small areas of different soils may be included within the
mapped areas of a specific soil.
The information is not site specific and does not eliminate the need for onsite
investigation of the soils or for testing and analysis by personnel experienced in the
design and construction of engineering works.
Government ordinances and regulations that restrict certain land uses or impose
specific design criteria were not considered in preparing the information in this table.
Local ordinances and regulations should be considered in planning, in site selection,
and in design.
Report—Roads and Streets, Shallow Excavations, and Lawns and
Landscaping
[Onsite investigation may be needed to validate the interpretations in this table and to
confirm the identity of the soil on a given site. The numbers in the value columns range
from 0.01 to 1.00. The larger the value, the greater the potential limitation. The table
shows only the top five limitations for any given soil. The soil may have additional
limitations]
Custom Soil Resource Report
80
Roads and Streets, Shallow Excavations, and Lawns and Landscaping– Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Map symbol and soil
name
Pct. of
map
unit
Local roads and streets Shallow excavations Lawns and landscaping
Rating class and
limiting features
Value Rating class and
limiting features
Value Rating class and
limiting features
Value
34—Ildefonso stony
loam, 25 to 45
percent slopes
Ildefonso 90 Very limited Very limited Very limited
Slope 1.00 Slope 1.00 Slope 1.00
Large stones content 1.00 Large stones content 1.00 Large stones content 0.84
Cutbanks cave 0.10 Droughty 0.13
56—Potts loam, 6 to 12
percent slopes
Potts 85 Very limited Somewhat limited Somewhat limited
Low strength 1.00 Cutbanks cave 0.10 Slope 0.04
Shrink-swell 0.50 Slope 0.04
Slope 0.04
58—Potts-Ildefonso
complex, 12 to 25
percent slopes
Potts 60 Very limited Very limited Very limited
Slope 1.00 Slope 1.00 Slope 1.00
Low strength 1.00 Cutbanks cave 0.10
Shrink-swell 0.50
Ildefonso 30 Very limited Very limited Very limited
Slope 1.00 Slope 1.00 Slope 1.00
Large stones content 1.00 Large stones content 1.00 Large stones content 0.84
Cutbanks cave 0.10 Droughty 0.13
66—Torriorthents-
Camborthids-Rock
outcrop complex,
steep
Torriorthents, steep 45 Very limited Very limited Not rated
Depth to hard bedrock 1.00 Depth to hard bedrock 1.00
Slope 1.00 Slope 1.00
Camborthids, steep 20 Very limited Very limited Very limited
Slope 1.00 Depth to hard bedrock 1.00 Slope 1.00
Shrink-swell 0.50 Slope 1.00 Depth to bedrock 0.02
Low strength 0.22 Cutbanks cave 0.10 Droughty 0.01
Depth to hard bedrock 0.02
Rock outcrop, steep 15 Not rated Not rated Not rated
Custom Soil Resource Report
81
Roads and Streets, Shallow Excavations, and Lawns and Landscaping– Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Map symbol and soil
name
Pct. of
map
unit
Local roads and streets Shallow excavations Lawns and landscaping
Rating class and
limiting features
Value Rating class and
limiting features
Value Rating class and
limiting features
Value
67—Torriorthents-
Rock outcrop
complex, steep
Torriorthents, steep 60 Very limited Very limited Not rated
Depth to hard bedrock 1.00 Depth to hard bedrock 1.00
Slope 1.00 Slope 1.00
Rock outcrop, steep 25 Not rated Not rated Not rated
Soil Chemical Properties
This folder contains a collection of tabular reports that present soil chemical properties.
The reports (tables) include all selected map units and components for each map unit.
Soil chemical properties are measured or inferred from direct observations in the field
or laboratory. Examples of soil chemical properties include pH, cation exchange
capacity, calcium carbonate, gypsum, and electrical conductivity.
Chemical Soil Properties
This table shows estimates of some chemical characteristics and features that affect
soil behavior. These estimates are given for the layers of each soil in the survey area.
The estimates are based on field observations and on test data for these and similar
soils.
Depth to the upper and lower boundaries of each layer is indicated.
Cation-exchange capacity is the total amount of extractable cations that can be held
by the soil, expressed in terms of milliequivalents per 100 grams of soil at neutrality
(pH 7.0) or at some other stated pH value. Soils having a low cation-exchange capacity
hold fewer cations and may require more frequent applications of fertilizer than soils
having a high cation-exchange capacity. The ability to retain cations reduces the
hazard of ground-water pollution.
Effective cation-exchange capacity refers to the sum of extractable cations plus
aluminum expressed in terms of milliequivalents per 100 grams of soil. It is determined
for soils that have pH of less than 5.5.
Soil reaction is a measure of acidity or alkalinity. It is important in selecting crops and
other plants, in evaluating soil amendments for fertility and stabilization, and in
determining the risk of corrosion.
Calcium carbonate equivalent is the percent of carbonates, by weight, in the fraction
of the soil less than 2 millimeters in size. The availability of plant nutrients is influenced
by the amount of carbonates in the soil.
Gypsum is expressed as a percent, by weight, of hydrated calcium sulfates in the
fraction of the soil less than 20 millimeters in size. Gypsum is partially soluble in water.
Custom Soil Resource Report
82
Soils that have a high content of gypsum may collapse if the gypsum is removed by
percolating water.
Salinity is a measure of soluble salts in the soil at saturation. It is expressed as the
electrical conductivity of the saturation extract, in millimhos per centimeter at 25
degrees C. Estimates are based on field and laboratory measurements at
representative sites of nonirrigated soils. The salinity of irrigated soils is affected by
the quality of the irrigation water and by the frequency of water application. Hence,
the salinity of soils in individual fields can differ greatly from the value given in the
table. Salinity affects the suitability of a soil for crop production, the stability of soil if
used as construction material, and the potential of the soil to corrode metal and
concrete.
Sodium adsorption ratio (SAR) is a measure of the amount of sodium (Na) relative to
calcium (Ca) and magnesium (Mg) in the water extract from saturated soil paste. It is
the ratio of the Na concentration divided by the square root of one-half of the Ca + Mg
concentration. Soils that have SAR values of 13 or more may be characterized by an
increased dispersion of organic matter and clay particles, reduced saturated hydraulic
conductivity and aeration, and a general degradation of soil structure.
Custom Soil Resource Report
83
Chemical Soil Properties– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil name Depth Cation-
exchange
capacity
Effective
cation-
exchange
capacity
Soil reaction Calcium
carbonate
Gypsum Salinity Sodium
adsorption ratio
In meq/100g meq/100g pH Pct Pct mmhos/cm
34—Ildefonso stony loam, 25 to 45
percent slopes
Ildefonso 0-8 5.0-20 —7.4-8.4 5-15 0 0.0-2.0 0
8-60 5.0-15 —7.9-8.4 15-35 0 0.0-4.0 0
56—Potts loam, 6 to 12 percent
slopes
Potts 0-4 5.0-15 —7.4-7.8 0-2 0 0 0
4-28 10-20 —7.4-7.8 0-5 0 0 0
28-60 5.0-15 —7.9-9.0 5-15 0 0.0-2.0 0
58—Potts-Ildefonso complex, 12 to
25 percent slopes
Potts 0-4 5.0-15 —7.4-7.8 0-2 0 0 0
4-28 10-20 —7.4-7.8 0-5 0 0 0
28-60 5.0-15 —7.9-9.0 5-15 0 0.0-2.0 0
Ildefonso 0-8 5.0-20 —7.4-8.4 5-15 0 0.0-2.0 0
8-60 5.0-15 —7.9-8.4 15-35 0 0.0-4.0 0
66—Torriorthents-Camborthids-
Rock outcrop complex, steep
Torriorthents, steep 0-4 ——6.1-8.4 0-5 0 0.0-2.0 0
4-30 5.0-20 —6.1-8.4 0-5 0 0.0-2.0 0
30-34 ———————
Camborthids, steep 0-4 5.0-20 —6.1-8.4 5-10 0-2 0.0-2.0 0
4-30 5.0-20 —6.1-8.4 5-10 0-2 0.0-2.0 0
30-34 ———————
Rock outcrop, steep 0-60 —————0 —
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Chemical Soil Properties– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil name Depth Cation-
exchange
capacity
Effective
cation-
exchange
capacity
Soil reaction Calcium
carbonate
Gypsum Salinity Sodium
adsorption ratio
In meq/100g meq/100g pH Pct Pct mmhos/cm
67—Torriorthents-Rock outcrop
complex, steep
Torriorthents, steep 0-4 ——6.1-8.4 0-5 0 0.0-2.0 0
4-30 5.0-20 —6.1-8.4 0-5 0 0.0-2.0 0
30-34 ———————
Rock outcrop, steep 0-60 —————0 —
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Soil Physical Properties
This folder contains a collection of tabular reports that present soil physical properties.
The reports (tables) include all selected map units and components for each map unit.
Soil physical properties are measured or inferred from direct observations in the field
or laboratory. Examples of soil physical properties include percent clay, organic
matter, saturated hydraulic conductivity, available water capacity, and bulk density.
Particle Size and Coarse Fragments
This table shows estimates of particle size distribution and coarse fragment content
of each soil in the survey area. The estimates are based on field observations and on
test data for these and similar soils.
Depth to the upper and lower boundaries of each layer is indicated.
Particle size is the effective diameter of a soil particle as measured by sedimentation,
sieving, or micrometric methods. Particle sizes are expressed as classes with specific
effective diameter class limits. The broad classes are sand, silt, and clay, ranging from
the larger to the smaller.
Sand as a soil separate consists of mineral soil particles that are 0.05 millimeter to 2
millimeters in diameter. In this table, the estimated sand content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters in
diameter.
Silt as a soil separate consists of mineral soil particles that are 0.002 to 0.05 millimeter
in diameter. In this table, the estimated silt content of each soil layer is given as a
percentage, by weight, of the soil material that is less than 2 millimeters in diameter.
Clay as a soil separate consists of mineral soil particles that are less than 0.002
millimeter in diameter. In this table, the estimated clay content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters in
diameter.
The content of sand, silt, and clay affects the physical behavior of a soil. Particle size
is important for engineering and agronomic interpretations, for determination of soil
hydrologic qualities, and for soil classification.
The amount and kind of clay affect the fertility and physical condition of the soil and
the ability of the soil to adsorb cations and to retain moisture. They influence shrink-
swell potential, saturated hydraulic conductivity (Ksat), plasticity, the ease of soil
dispersion, and other soil properties. The amount and kind of clay in a soil also affect
tillage and earthmoving operations.
Total fragments is the content of fragments of rock and other materials larger than 2
millimeters in diameter on volumetric basis of the whole soil.
Fragments 2-74 mm refers to the content of coarse fragments in the 2 to 74 millimeter
size fraction.
Fragments 75-249 mm refers to the content of coarse fragments in teh 75 to 249
millimeter size fraction.
Fragments 250-599 mm refers to the content of coarse fragments in the 250 to 599
millimeter size fraction.
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Fragments >=600 mm refers to the content of coarse fragments in the greater than or
equal to 600 millimeter size fraction.
Reference:
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. (http://soils.usda.gov)
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Particle Size and Coarse Fragments– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil
name
Horizon Depth Sand Silt Clay Total fragments Fragments 2-74
mm
Fragments 75-249
mm
Fragments
250-599 mm
Fragments
>=600 mm
In L-RV-H
Pct
L-RV-H
Pct
L-RV-H Pct RV Pct RV Pct RV Pct RV Pct RV Pct
34—Ildefonso stony
loam, 25 to 45
percent slopes
Ildefonso H1 0-8 -42--38-15-20- 25 27 13 9 —5
H2 8-60 -42--38-15-20- 25 59 23 12 —24
56—Potts loam, 6 to
12 percent slopes
Potts H1 0-4 -44--41-10-15- 20 —————
H2 4-28 -33--36-27-31- 34 —————
H3 28-60 -42--38-15-20- 25 —————
58—Potts-Ildefonso
complex, 12 to 25
percent slopes
Potts H1 0-4 -44--41-10-15- 20 —————
H2 4-28 -33--36-27-31- 34 —————
H3 28-60 -42--38-15-20- 25 —————
Ildefonso H1 0-8 -42--38-15-20- 25 27 13 9 —5
H2 8-60 -42--38-15-20- 25 59 23 12 —24
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Particle Size and Coarse Fragments– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil
name
Horizon Depth Sand Silt Clay Total fragments Fragments 2-74
mm
Fragments 75-249
mm
Fragments
250-599 mm
Fragments
>=600 mm
In L-RV-H
Pct
L-RV-H
Pct
L-RV-H Pct RV Pct RV Pct RV Pct RV Pct RV Pct
66—Torriorthents-
Camborthids-Rock
outcrop complex,
steep
Torriorthents, steep H1 0-4 ————————
H2 4-30 -61--19-5-20- 35 14 10 4 ——
H3 30-34 ————————
Camborthids, steep H1 0-4 ——15-23- 30 0 0 0 —0
H2 4-30 -37--35-20-28- 35 9 7 2 ——
H3 30-34 ————————
Rock outcrop, steep H1 0-60 ——0- 0- 0 —————
67—Torriorthents-
Rock outcrop
complex, steep
Torriorthents, steep H1 0-4 ————————
H2 4-30 -61--19-5-20- 35 14 10 4 ——
H3 30-34 ————————
Rock outcrop, steep H1 0-60 ——0- 0- 0 —————
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Physical Soil Properties
This table shows estimates of some physical characteristics and features that affect
soil behavior. These estimates are given for the layers of each soil in the survey area.
The estimates are based on field observations and on test data for these and similar
soils.
Depth to the upper and lower boundaries of each layer is indicated.
Particle size is the effective diameter of a soil particle as measured by sedimentation,
sieving, or micrometric methods. Particle sizes are expressed as classes with specific
effective diameter class limits. The broad classes are sand, silt, and clay, ranging from
the larger to the smaller.
Sand as a soil separate consists of mineral soil particles that are 0.05 millimeter to 2
millimeters in diameter. In this table, the estimated sand content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters in
diameter.
Silt as a soil separate consists of mineral soil particles that are 0.002 to 0.05 millimeter
in diameter. In this table, the estimated silt content of each soil layer is given as a
percentage, by weight, of the soil material that is less than 2 millimeters in diameter.
Clay as a soil separate consists of mineral soil particles that are less than 0.002
millimeter in diameter. In this table, the estimated clay content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters in
diameter.
The content of sand, silt, and clay affects the physical behavior of a soil. Particle size
is important for engineering and agronomic interpretations, for determination of soil
hydrologic qualities, and for soil classification.
The amount and kind of clay affect the fertility and physical condition of the soil and
the ability of the soil to adsorb cations and to retain moisture. They influence shrink-
swell potential, saturated hydraulic conductivity (Ksat), plasticity, the ease of soil
dispersion, and other soil properties. The amount and kind of clay in a soil also affect
tillage and earthmoving operations.
Moist bulk density is the weight of soil (ovendry) per unit volume. Volume is measured
when the soil is at field moisture capacity, that is, the moisture content at 1/3- or 1/10-
bar (33kPa or 10kPa) moisture tension. Weight is determined after the soil is dried at
105 degrees C. In the table, the estimated moist bulk density of each soil horizon is
expressed in grams per cubic centimeter of soil material that is less than 2 millimeters
in diameter. Bulk density data are used to compute linear extensibility, shrink-swell
potential, available water capacity, total pore space, and other soil properties. The
moist bulk density of a soil indicates the pore space available for water and roots.
Depending on soil texture, a bulk density of more than 1.4 can restrict water storage
and root penetration. Moist bulk density is influenced by texture, kind of clay, content
of organic matter, and soil structure.
Saturated hydraulic conductivity (Ksat) refers to the ease with which pores in a
saturated soil transmit water. The estimates in the table are expressed in terms of
micrometers per second. They are based on soil characteristics observed in the field,
particularly structure, porosity, and texture. Saturated hydraulic conductivity (Ksat) is
considered in the design of soil drainage systems and septic tank absorption fields.
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Available water capacity refers to the quantity of water that the soil is capable of storing
for use by plants. The capacity for water storage is given in inches of water per inch
of soil for each soil layer. The capacity varies, depending on soil properties that affect
retention of water. The most important properties are the content of organic matter,
soil texture, bulk density, and soil structure. Available water capacity is an important
factor in the choice of plants or crops to be grown and in the design and management
of irrigation systems. Available water capacity is not an estimate of the quantity of
water actually available to plants at any given time.
Linear extensibility refers to the change in length of an unconfined clod as moisture
content is decreased from a moist to a dry state. It is an expression of the volume
change between the water content of the clod at 1/3- or 1/10-bar tension (33kPa or
10kPa tension) and oven dryness. The volume change is reported in the table as
percent change for the whole soil. The amount and type of clay minerals in the soil
influence volume change.
Linear extensibility is used to determine the shrink-swell potential of soils. The shrink-
swell potential is low if the soil has a linear extensibility of less than 3 percent; moderate
if 3 to 6 percent; high if 6 to 9 percent; and very high if more than 9 percent. If the
linear extensibility is more than 3, shrinking and swelling can cause damage to
buildings, roads, and other structures and to plant roots. Special design commonly is
needed.
Organic matter is the plant and animal residue in the soil at various stages of
decomposition. In this table, the estimated content of organic matter is expressed as
a percentage, by weight, of the soil material that is less than 2 millimeters in diameter.
The content of organic matter in a soil can be maintained by returning crop residue to
the soil.
Organic matter has a positive effect on available water capacity, water infiltration, soil
organism activity, and tilth. It is a source of nitrogen and other nutrients for crops and
soil organisms.
Erosion factors are shown in the table as the K factor (Kw and Kf) and the T factor.
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by water.
Factor K is one of six factors used in the Universal Soil Loss Equation (USLE) and the
Revised Universal Soil Loss Equation (RUSLE) to predict the average annual rate of
soil loss by sheet and rill erosion in tons per acre per year. The estimates are based
primarily on percentage of silt, sand, and organic matter and on soil structure and Ksat.
Values of K range from 0.02 to 0.69. Other factors being equal, the higher the value,
the more susceptible the soil is to sheet and rill erosion by water.
Erosion factor Kw indicates the erodibility of the whole soil. The estimates are modified
by the presence of rock fragments.
Erosion factor Kf indicates the erodibility of the fine-earth fraction, or the material less
than 2 millimeters in size.
Erosion factor T is an estimate of the maximum average annual rate of soil erosion by
wind and/or water that can occur without affecting crop productivity over a sustained
period. The rate is in tons per acre per year.
Wind erodibility groups are made up of soils that have similar properties affecting their
susceptibility to wind erosion in cultivated areas. The soils assigned to group 1 are the
most susceptible to wind erosion, and those assigned to group 8 are the least
susceptible. The groups are described in the "National Soil Survey Handbook."
Wind erodibility index is a numerical value indicating the susceptibility of soil to wind
erosion, or the tons per acre per year that can be expected to be lost to wind erosion.
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There is a close correlation between wind erosion and the texture of the surface layer,
the size and durability of surface clods, rock fragments, organic matter, and a
calcareous reaction. Soil moisture and frozen soil layers also influence wind erosion.
Reference:
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. (http://soils.usda.gov)
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Physical Soil Properties– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol
and soil name
Depth Sand Silt Clay Moist
bulk
density
Saturated
hydraulic
conductivity
Available
water
capacity
Linear
extensibility
Organic
matter
Erosion factors Wind
erodibility
group
Wind
erodibility
indexKwKfT
In Pct Pct Pct g/cc micro m/sec In/In Pct Pct
34—Ildefonso
stony loam,
25 to 45
percent
slopes
Ildefonso 0-8 -42--38-15-20- 25 1.25-1.40 4.23-42.34 0.10-0.13 0.0-2.9 1.0-2.0 .15 .28 5 4L 86
8-60 -42--38-15-20- 25 1.25-1.40 4.23-42.34 0.07-0.09 0.0-2.9 0.5-1.0 .15 .37
56—Potts loam,
6 to 12
percent
slopes
Potts 0-4 -44--41-10-15- 20 1.25-1.40 4.23-42.34 0.14-0.17 0.0-2.9 1.0-2.0 .28 .28 5 4L 86
4-28 -33--36-27-31- 34 1.25-1.40 1.41-4.23 0.17-0.20 3.0-5.9 0.5-1.0 .24 .24
28-60 -42--38-15-20- 25 1.25-1.40 4.23-42.34 0.14-0.17 0.0-2.9 0.0-0.5 .43 .43
58—Potts-
Ildefonso
complex, 12
to 25 percent
slopes
Potts 0-4 -44--41-10-15- 20 1.25-1.40 4.23-42.34 0.14-0.17 0.0-2.9 1.0-2.0 .28 .28 5 4L 86
4-28 -33--36-27-31- 34 1.25-1.40 1.41-4.23 0.17-0.20 3.0-5.9 0.5-1.0 .24 .24
28-60 -42--38-15-20- 25 1.25-1.40 4.23-42.34 0.14-0.17 0.0-2.9 0.0-0.5 .43 .43
Ildefonso 0-8 -42--38-15-20- 25 1.25-1.40 4.23-42.34 0.10-0.13 0.0-2.9 1.0-2.0 .15 .28 5 4L 86
8-60 -42--38-15-20- 25 1.25-1.40 4.23-42.34 0.07-0.09 0.0-2.9 0.5-1.0 .15 .37
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Physical Soil Properties– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol
and soil name
Depth Sand Silt Clay Moist
bulk
density
Saturated
hydraulic
conductivity
Available
water
capacity
Linear
extensibility
Organic
matter
Erosion factors Wind
erodibility
group
Wind
erodibility
indexKwKfT
In Pct Pct Pct g/cc micro m/sec In/In Pct Pct
66—
Torriorthents-
Camborthids-
Rock outcrop
complex,
steep
Torriorthents,
steep
0-4 ————1.40-42.00 0.04-0.18 —0.5-1.0
4-30 -61--19-5-20- 35 1.30-1.50 4.23-14.11 0.10-0.18 0.0-2.9 0.0-0.5 .32 .32
30-34 ————0.42-1.41 ———
Camborthids,
steep
0-4 ——15-23- 30 1.20-1.30 1.41-42.34 0.06-0.10 0.0-2.9 0.5-1.0 .15 .28 2 8 0
4-30 -37--35-20-28- 35 1.40-1.50 4.23-14.11 0.12-0.16 3.0-5.9 0.0-0.5 .28 .28
30-34 ————0.42-1.41 ———
Rock outcrop,
steep
0-60 ——0- 0- 0 —0.00-1.40 0.00 ——8 0
67—
Torriorthents-
Rock outcrop
complex,
steep
Torriorthents,
steep
0-4 ————1.40-42.00 0.04-0.18 —0.5-1.0
4-30 -61--19-5-20- 35 1.30-1.50 4.23-14.11 0.10-0.18 0.0-2.9 0.0-0.5 .32 .32
30-34 ————0.42-1.41 ———
Rock outcrop,
steep
0-60 ——0- 0- 0 —0.00-1.40 0.00 ——8 0
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Soil Qualities and Features
This folder contains tabular reports that present various soil qualities and features.
The reports (tables) include all selected map units and components for each map unit.
Soil qualities are behavior and performance attributes that are not directly measured,
but are inferred from observations of dynamic conditions and from soil properties.
Example soil qualities include natural drainage, and frost action. Soil features are
attributes that are not directly part of the soil. Example soil features include slope and
depth to restrictive layer. These features can greatly impact the use and management
of the soil.
Soil Features
This table gives estimates of various soil features. The estimates are used in land use
planning that involves engineering considerations.
A restrictive layer is a nearly continuous layer that has one or more physical, chemical,
or thermal properties that significantly impede the movement of water and air through
the soil or that restrict roots or otherwise provide an unfavorable root environment.
Examples are bedrock, cemented layers, dense layers, and frozen layers. The table
indicates the hardness and thickness of the restrictive layer, both of which significantly
affect the ease of excavation. Depth to top is the vertical distance from the soil surface
to the upper boundary of the restrictive layer.
Subsidence is the settlement of organic soils or of saturated mineral soils of very low
density. Subsidence generally results from either desiccation and shrinkage, or
oxidation of organic material, or both, following drainage. Subsidence takes place
gradually, usually over a period of several years. The table shows the expected initial
subsidence, which usually is a result of drainage, and total subsidence, which results
from a combination of factors.
Potential for frost action is the likelihood of upward or lateral expansion of the soil
caused by the formation of segregated ice lenses (frost heave) and the subsequent
collapse of the soil and loss of strength on thawing. Frost action occurs when moisture
moves into the freezing zone of the soil. Temperature, texture, density, saturated
hydraulic conductivity (Ksat), content of organic matter, and depth to the water table
are the most important factors considered in evaluating the potential for frost action.
It is assumed that the soil is not insulated by vegetation or snow and is not artificially
drained. Silty and highly structured, clayey soils that have a high water table in winter
are the most susceptible to frost action. Well drained, very gravelly, or very sandy soils
are the least susceptible. Frost heave and low soil strength during thawing cause
damage to pavements and other rigid structures.
Risk of corrosion pertains to potential soil-induced electrochemical or chemical action
that corrodes or weakens uncoated steel or concrete. The rate of corrosion of
uncoated steel is related to such factors as soil moisture, particle-size distribution,
acidity, and electrical conductivity of the soil. The rate of corrosion of concrete is based
mainly on the sulfate and sodium content, texture, moisture content, and acidity of the
soil. Special site examination and design may be needed if the combination of factors
results in a severe hazard of corrosion. The steel or concrete in installations that
intersect soil boundaries or soil layers is more susceptible to corrosion than the steel
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or concrete in installations that are entirely within one kind of soil or within one soil
layer.
For uncoated steel, the risk of corrosion, expressed as low, moderate, or high, is based
on soil drainage class, total acidity, electrical resistivity near field capacity, and
electrical conductivity of the saturation extract.
For concrete, the risk of corrosion also is expressed as low, moderate, or high. It is
based on soil texture, acidity, and amount of sulfates in the saturation extract.
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Soil Features– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and
soil name
Restrictive Layer Subsidence Potential for frost
action
Risk of corrosion
Kind Depth to
top
Thickness Hardness Initial Total Uncoated steel Concrete
In In In In
34—Ildefonso stony
loam, 25 to 45
percent slopes
Ildefonso ——0 —Low Moderate Low
56—Potts loam, 6 to
12 percent slopes
Potts ——0 —Low High High
58—Potts-Ildefonso
complex, 12 to 25
percent slopes
Potts ——0 —Low High High
Ildefonso ——0 —Low Moderate Low
66—Torriorthents-
Camborthids-
Rock outcrop
complex, steep
Torriorthents,
steep
Lithic bedrock 4-30 —Indurated 0 —Low High Low
Camborthids,
steep
Lithic bedrock 15-60 —Indurated 0 —Low High Low
Rock outcrop,
steep
Paralithic bedrock 0 —Moderately
cemented
0 —None
67—Torriorthents-
Rock outcrop
complex, steep
Torriorthents,
steep
Lithic bedrock 4-30 —Indurated 0 —Low High Low
Rock outcrop,
steep
Paralithic bedrock 0 —Moderately
cemented
0 —None
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Water Features
This folder contains tabular reports that present soil hydrology information. The reports
(tables) include all selected map units and components for each map unit. Water
Features include ponding frequency, flooding frequency, and depth to water table.
Water Features
This table gives estimates of various soil water features. The estimates are used in
land use planning that involves engineering considerations.
Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned
to one of four groups according to the rate of water infiltration when the soils are not
protected by vegetation, are thoroughly wet, and receive precipitation from long-
duration storms.
The four hydrologic soil groups are:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist
chiefly of moderately deep or deep, moderately well drained or well drained soils that
have moderately fine texture to moderately coarse texture. These soils have a
moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or soils
of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential,
soils that have a high water table, soils that have a claypan or clay layer at or near the
surface, and soils that are shallow over nearly impervious material. These soils have
a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for
drained areas and the second is for undrained areas.
Surface runoff refers to the loss of water from an area by flow over the land surface.
Surface runoff classes are based on slope, climate, and vegetative cover. The concept
indicates relative runoff for very specific conditions. It is assumed that the surface of
the soil is bare and that the retention of surface water resulting from irregularities in
the ground surface is minimal. The classes are negligible, very low, low, medium, high,
and very high.
The months in the table indicate the portion of the year in which a water table, ponding,
and/or flooding is most likely to be a concern.
Water table refers to a saturated zone in the soil. The water features table indicates,
by month, depth to the top (upper limit) and base (lower limit) of the saturated zone in
most years. Estimates of the upper and lower limits are based mainly on observations
of the water table at selected sites and on evidence of a saturated zone, namely
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grayish colors or mottles (redoximorphic features) in the soil. A saturated zone that
lasts for less than a month is not considered a water table.
Ponding is standing water in a closed depression. Unless a drainage system is
installed, the water is removed only by percolation, transpiration, or evaporation. The
table indicates surface water depth and the duration and frequency of ponding.
Duration is expressed as very brief if less than 2 days, brief if 2 to 7 days, long if 7 to
30 days, and very long if more than 30 days. Frequency is expressed as none, rare,
occasional, and frequent. None means that ponding is not probable; rare that it is
unlikely but possible under unusual weather conditions (the chance of ponding is
nearly 0 percent to 5 percent in any year); occasional that it occurs, on the average,
once or less in 2 years (the chance of ponding is 5 to 50 percent in any year); and
frequent that it occurs, on the average, more than once in 2 years (the chance of
ponding is more than 50 percent in any year).
Flooding is the temporary inundation of an area caused by overflowing streams, by
runoff from adjacent slopes, or by tides. Water standing for short periods after rainfall
or snowmelt is not considered flooding, and water standing in swamps and marshes
is considered ponding rather than flooding.
Duration and frequency are estimated. Duration is expressed as extremely brief if 0.1
hour to 4 hours, very brief if 4 hours to 2 days, brief if 2 to 7 days, long if 7 to 30 days,
and very long if more than 30 days. Frequency is expressed as none, very rare, rare,
occasional, frequent, and very frequent. None means that flooding is not probable;
very rare that it is very unlikely but possible under extremely unusual weather
conditions (the chance of flooding is less than 1 percent in any year); rare that it is
unlikely but possible under unusual weather conditions (the chance of flooding is 1 to
5 percent in any year); occasional that it occurs infrequently under normal weather
conditions (the chance of flooding is 5 to 50 percent in any year); frequent that it is
likely to occur often under normal weather conditions (the chance of flooding is more
than 50 percent in any year but is less than 50 percent in all months in any year); and
very frequent that it is likely to occur very often under normal weather conditions (the
chance of flooding is more than 50 percent in all months of any year).
The information is based on evidence in the soil profile, namely thin strata of gravel,
sand, silt, or clay deposited by floodwater; irregular decrease in organic matter content
with increasing depth; and little or no horizon development.
Also considered are local information about the extent and levels of flooding and the
relation of each soil on the landscape to historic floods. Information on the extent of
flooding based on soil data is less specific than that provided by detailed engineering
surveys that delineate flood-prone areas at specific flood frequency levels.
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Water Features– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map unit symbol and soil
name
Hydrologic
group
Surface
runoff
Month Water table Ponding Flooding
Upper limit Lower limit Surface
depth
Duration Frequency Duration Frequency
Ft Ft Ft
34—Ildefonso stony loam, 25
to 45 percent slopes
Ildefonso B Medium Jan-Dec ————None ——
56—Potts loam, 6 to 12
percent slopes
Potts B High Jan-Dec ————None ——
58—Potts-Ildefonso complex,
12 to 25 percent slopes
Potts B High Jan-Dec ————None ——
Ildefonso B Low Jan-Dec ————None ——
66—Torriorthents-
Camborthids-Rock outcrop
complex, steep
Torriorthents, steep D High Jan-Dec ————None ——
Camborthids, steep D High Jan-Dec ————None ——
Rock outcrop, steep D Very high Jan-Dec ————None ——
67—Torriorthents-Rock
outcrop complex, steep
Torriorthents, steep D High Jan-Dec ————None ——
Rock outcrop, steep D Very high Jan-Dec ————None ——
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Water Management
This folder contains a collection of tabular reports that present soil interpretations
related to water management. The reports (tables) include all selected map units and
components for each map unit, limiting features and interpretive ratings. Water
management interpretations are tools for evaluating the potential of the soil in the
application of various water management practices. Example interpretations include
pond reservoir area, embankments, dikes, levees, and excavated ponds.
Ponds and Embankments
This table gives information on the soil properties and site features that affect water
management. The degree and kind of soil limitations are given for pond reservoir
areas; embankments, dikes, and levees; and aquifer-fed excavated ponds. The
ratings are both verbal and numerical. Rating class terms indicate the extent to which
the soils are limited by all of the soil features that affect these uses. Not limited
indicates that the soil has features that are very favorable for the specified use. Good
performance and very low maintenance can be expected. Somewhat limited indicates
that the soil has features that are moderately favorable for the specified use. The
limitations can be overcome or minimized by special planning, design, or installation.
Fair performance and moderate maintenance can be expected. Very limited indicates
that the soil has one or more features that are unfavorable for the specified use. The
limitations generally cannot be overcome without major soil reclamation, special
design, or expensive installation procedures. Poor performance and high
maintenance can be expected.
Numerical ratings in the table indicate the severity of individual limitations. The ratings
are shown as decimal fractions ranging from 0.01 to 1.00. They indicate gradations
between the point at which a soil feature has the greatest negative impact on the use
(1.00) and the point at which the soil feature is not a limitation (0.00).
Pond reservoir areas hold water behind a dam or embankment. Soils best suited to
this use have low seepage potential in the upper 60 inches. The seepage potential is
determined by the saturated hydraulic conductivity (Ksat) of the soil and the depth to
fractured bedrock or other permeable material. Excessive slope can affect the storage
capacity of the reservoir area.
Embankments, dikes, and levees are raised structures of soil material, generally less
than 20 feet high, constructed to impound water or to protect land against overflow.
Embankments that have zoned construction (core and shell) are not considered. In
this table, the soils are rated as a source of material for embankment fill. The ratings
apply to the soil material below the surface layer to a depth of 5 or 6 feet. It is assumed
that soil layers will be uniformly mixed and compacted during construction.
The ratings do not indicate the ability of the natural soil to support an embankment.
Soil properties to a depth even greater than the height of the embankment can affect
performance and safety of the embankment. Generally, deeper onsite investigation is
needed to determine these properties.
Soil material in embankments must be resistant to seepage, piping, and erosion and
have favorable compaction characteristics. Unfavorable features include less than 5
feet of suitable material and a high content of stones or boulders, organic matter, or
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salts or sodium. A high water table affects the amount of usable material. It also affects
trafficability.
Aquifer-fed excavated ponds are pits or dugouts that extend to a ground-water aquifer
or to a depth below a permanent water table. Excluded are ponds that are fed only by
surface runoff and embankment ponds that impound water 3 feet or more above the
original surface. Excavated ponds are affected by depth to a permanent water table,
Ksat of the aquifer, and quality of the water as inferred from the salinity of the soil.
Depth to bedrock and the content of large stones affect the ease of excavation.
Information in this table is intended for land use planning, for evaluating land use
alternatives, and for planning site investigations prior to design and construction. The
information, however, has limitations. For example, estimates and other data generally
apply only to that part of the soil between the surface and a depth of 5 to 7 feet.
Because of the map scale, small areas of different soils may be included within the
mapped areas of a specific soil.
The information is not site specific and does not eliminate the need for onsite
investigation of the soils or for testing and analysis by personnel experienced in the
design and construction of engineering works.
Government ordinances and regulations that restrict certain land uses or impose
specific design criteria were not considered in preparing the information in this table.
Local ordinances and regulations should be considered in planning, in site selection,
and in design.
Report—Ponds and Embankments
[Onsite investigation may be needed to validate the interpretations in this table and to
confirm the identity of the soil on a given site. The numbers in the value columns range
from 0.01 to 1.00. The larger the value, the greater the potential limitation. The table
shows only the top five limitations for any given soil. The soil may have additional
limitations]
Ponds and Embankments– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil
name
Pct. of
map
unit
Pond reservoir areas Embankments, dikes, and
levees
Aquifer-fed excavated ponds
Rating class and
limiting features
Value Rating class and
limiting features
Value Rating class and
limiting features
Value
34—Ildefonso stony
loam, 25 to 45
percent slopes
Ildefonso 90 Very limited Very limited Very limited
Slope 1.00 Large stones content 1.00 Depth to water 1.00
Seepage 1.00
56—Potts loam, 6 to 12
percent slopes
Potts 85 Very limited Very limited Very limited
Slope 1.00 Piping 0.99 Depth to water 1.00
Seepage 1.00
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Ponds and Embankments– Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil
name
Pct. of
map
unit
Pond reservoir areas Embankments, dikes, and
levees
Aquifer-fed excavated ponds
Rating class and
limiting features
Value Rating class and
limiting features
Value Rating class and
limiting features
Value
58—Potts-Ildefonso
complex, 12 to 25
percent slopes
Potts 60 Very limited Very limited Very limited
Slope 1.00 Piping 0.99 Depth to water 1.00
Seepage 1.00
Ildefonso 30 Very limited Very limited Very limited
Slope 1.00 Large stones content 1.00 Depth to water 1.00
Seepage 1.00
66—Torriorthents-
Camborthids-Rock
outcrop complex,
steep
Torriorthents, steep 45 Very limited Very limited Very limited
Slope 1.00 Thin layer 1.00 Depth to water 1.00
Depth to bedrock 1.00
Seepage 0.72
Camborthids, steep 20 Very limited Very limited Very limited
Slope 1.00 Piping 0.99 Depth to water 1.00
Seepage 0.72 Thin layer 0.59
Depth to bedrock 0.59
Rock outcrop, steep 15 Very limited Not rated Not rated
Slope 1.00
Depth to bedrock 1.00
67—Torriorthents-
Rock outcrop
complex, steep
Torriorthents, steep 60 Very limited Very limited Very limited
Slope 1.00 Thin layer 1.00 Depth to water 1.00
Depth to bedrock 1.00
Seepage 0.72
Rock outcrop, steep 25 Very limited Not rated Not rated
Slope 1.00
Depth to bedrock 1.00
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References
American Association of State Highway and Transportation Officials (AASHTO). 2004.
Standard specifications for transportation materials and methods of sampling and
testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service
FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils
in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S.
Department of Agriculture Handbook 18. http://soils.usda.gov/
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making
and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service,
U.S. Department of Agriculture Handbook 436. http://soils.usda.gov/
Soil Survey Staff. 2006. Keys to soil taxonomy. 10th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://soils.usda.gov/
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://soils.usda.gov/
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.glti.nrcs.usda.gov/
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://soils.usda.gov/
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States, the
Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
http://soils.usda.gov/
104
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210.
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