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GARFIELD COUNTY OWTS REPORT
LOT 31 MOUNTAIN SPRINGS RANCH
GARFIELD COUNTY, COLORADO
November 14, 2022
Prepared by
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004
970.945.5948 fax
Page 2 of 13
LOT 31 MOUNTAIN SPRINGS RANCH
GARFIELD COUNTY, COLORADO
“I hereby affirm that this report for the Onsite Wastewater Treatment System (OWTS) for Lot 31
Mountain Springs Ranch, Garfield County, Colorado was prepared by me or under my direct
supervision for the Owners thereof in accordance with the provisions of Garfield County’s Land Use
and OWTS Regulations and approved variances and exceptions listed thereto. I understand the
County does not and will not assume liability for OWTS facilities designed by others.”
______________________________________ License No. ____________________
Licensed Professional Engineer, State of Colorado (Affix Seal)
PREPARED BY:
RICK BARTH, P.E.
MAX WEISS, E.I.
SGM Project # 2022-432
Page 3 of 13
TABLE OF CONTENTS
1.0 Introduction 5
2.0 Preliminary Investigation 5
2.1 Property Information 5
2.2 Public Health Agency Records 5
2.3 Topography 5
2.4 Soil Data 5
2.5 Location of Physical Features 6
2.6 Additional Information 6
2.7 Landscape Position 6
2.8 Natural and Cultural Features 6
2.9 Current and Historic Land Use 6
3.0 Detailed Soil Investigation 6
3.1 Visual Evaluation 7
3.2 Tactile Evaluation 7
4.0 Recommendations 8
Page 4 of 13
Appendix
Sheet C1
Sheet C2
NRCS Soils Map
NRCS Absorption Field Soils Data
USDA Textural Triangle
SGM Soil Observation Logs
SGM Soil Texture by Feel
TP-1 Trench Photo
TP-2 Trench Photo
OWTS Design Spreadsheet
Pump Selection
Page 5 of 13
1.0 Introduction
Timothy O’Sullivan is proposing to develop a three-bedroom single family residence. To treat
wastewater from the proposed development, an onsite wastewater treatment system (OWTS) will be
installed.
This report describes the results of a preliminary investigation, reconnaissance, and detailed soil
evaluation to support design of the OWTS for the subject property, in addition to presenting design
of the system to be compliant with Garfield County’s “On Site Wastewater Treatment System
Regulations,” hereinafter referred to as Reg43.
SGM personnel contributing to this report are:
· Max Weiss - CPOW Certified Competent Technician/NAWT Certified Designer
· Rick L Barth – CPOW Certified Competent Technician/NAWT Certified Designer
2.0 Preliminary Investigation
2.1 Property Information
Physical Address: Mountain Springs Ranch Lot 31, Garfield County, Colorado.
Legal Description: Section: 20 Township: 6 Range: 89; TR of land in SE CONT 42.14A, also TR
CONT 5.11 in Lot 9. Account No. R070018, Parcel 218520300054.
Existing Structures: Presently, there are no existing structures on site.
Domestic Water: Provided by an existing well in the eastern portion of the subject property. The
well is located greater than the minimum setback requirement of 100 feet, Table 7-1 of Reg43.
2.2 Public Health Agency Records
Search of Garfield County’s Public Records did not reveal existing documents to indicate an
existing OWTS is already permitted for the subject property.
2.3 Topography
Existing topography in the vicinity of the OWTS slopes from northwest towards the southeast at
grades of between 9.0 to 12.0 percent. Grades are not proposed to change under proposed
conditions.
2.4 Soil Data
According to the Web Soil Survey for the Natural Resources Conservation Service (NRCS), soils
associated with this subject property are classified as map unit 19, Cochetopa-Jerry complex.
Cochetopa-Jerry has grades of between 25 to 50 percent, which does not agree with field
observation.
Cochetopa-Jerry also has a very limited rating for septic tank absorption fields due to filtering
capacity and slopes. However, plotting of percentages of clay, sand and silt given for this soil unit
on the USDA Textural Triangle indicates the soils would classify as soil type 3, 3A, 4 or 4A. Soils
having a classification type of 3 or 3A are suitable for absorption fields, having long term
Page 6 of 13
application rates (LTAR) of 0.35 and 0.3 gallons per day per square foot of area (gpd/ft2),
respectively, while soil types 4 and 4A are suitable for absorption fields, their LTAR is 0.2 and
0.15 gpd/ft2 respectively.
2.5 Location of Physical Features
Physical features on the subject property that will require minimum horizontal setbacks are shown
in the following Table. All distances are in feet.
Potable
Water
Structure with
Basement, Crawl
Space, Footing Drains
Property Lines, Piped
Irrigation
Dry
Gulch
Septic
Tank
Septic Tank 50 5 10 10 --
Effluent Line 50 N/A 10 10 --
STA 100 20 10 25 5
2.6 Additional Information
a. Easements: Easements are shown on sheet C1.
b. Floodplain Maps: According to FEMA (Federal Emergency Management Agency), the
subject property is in flood zone designation C, which is areas of minimal flooding as shown
on Community-Panel Number 080205 1433 B.
2.7 Landscape Position
The landscape position for the STA is considered summit and will not be impacted by stormwater
drainage. The slope shape is convex – concave (VC) towards the southeast.
2.8 Natural and Cultural Features
No natural or cultural features were identified in the site reconnaissance.
2.9 Current and Historic Land Use
The subject property is in Garfield County’s commercial zone district. Current and historic land
use has been commercial, its future use is expected to also be commercial.
3.0 Detailed Soil Investigation
A detailed soil investigation to determine the depth to the limiting layer, if any, and properly classify
the soil type was conducted on October 11, 2022. Visual evaluation of two soil profile test pits were
conducted in the field and samples collected from each test pit. The samples were taken to SGM’s
Office to classify the soil type that will receive the effluent waste using the soil texture by feel method.
Test pits were excavated adjacent to the proposed location for the STA, see sheet C1 for locations.
Visual evaluation of all test pits was conducted under adequate light conditions, with the soil being in
an unfrozen state.
Page 7 of 13
3.1 Visual Evaluation
The Client’s excavator excavated two soil profile test pits, TP-1 and TP-2, with SGM personnel
being on site. All test pits were excavated to an approximate depth of 5 to 8 feet, with no
groundwater nor bedrock being encountered. Observations of the excavated test pits show:
· Test pits TP-1 through TP-2 were excavated to a depth of 96 inches.
· Test pit TP-1 exhibited soils with clay loam texture, blocky soil structure shape, moderate
soil structure grade and soil consistence of firm from between 0 to 36 and sandy clay
loam with same structure and consistence as previously stated between 36 to 96 inches.
· Gravel became more prominent in test pits TP-2 and TP-3 at a depth of 60 inches.
· Test pit TP-2 exhibited soils having clay texture with blocky shape, strong structure
grade, and an extremely firm consistence from 0 to 48 inches. From depths of 48 to 96
inches the soil texture was a silty clay, with blocky structure shape, moderate structure
grade, and a firm consistence from 48 to 96 inches.
Soil observation logs and photos can be found in the Appendix.
All measurements are from ground surface.
3.2 Tactile Evaluation
SGM conducted a Soil Texture by Feel test on soil samples collected from test pits TP-1 and TP-
2 per CPOW’s methodology.
Gravels were present in both samples TP-1 and TP-2, predominantly not passing through the 2
mm sieve, therefore Table 10-1A, Section 43.10 of Reg43 was used to determine soil type and
the applicable long term application rate (LTAR) for this soil type.
Results of the soil texture by feel tests are shown in the following table.
SAMPLE
Sample
Depth from
Ground
Surface (ft)
Does Soil
Form a Ball
(yes/no)
Does Soil
Form a
Ribbon
(yes/no)
*Type of Ribbon
Formed (Weak,
Moderate,
Strong)
How Does the Soil Feel
(Gritty/Smooth/Neither)
TP-1a 3.0 Yes Yes Moderate Neither
TP-1b 7.0 Yes Yes Moderate Gritty
TP-2a 3.0 Yes Yes Strong Neither
TP-2b 7.0 Yes Yes Moderate Smooth
*Weak < 1 inch; Moderate 1-2 inches; Strong > 2 inches.
Results shown in the above table indicate a USDA soil classification of Clay Loam, type 3 or 3A
for the soils sampled from TP-1; for the soils sampled from TP-1 the indication is the soil is Silty
Clay, type 4 or 4A and since the volume of gravel was greater than 65 percent 2 mm rock, and
the non-gravel soils falling in the type 2-5 range, the soil type is R-2.
According to Table 10-1A, section 43.10 of Reg43, soil type R-2 requires a minimum 3-foot-deep
unlined sand filter with a maximum LTAR of 0.8 gpd/ft2 for receiving treatment level 1 (TL1)
effluent, and a timed, pressure distribution is required.
The USDA soil classification based on NRCS data for clay, sand and silt percentages in
subsection 2.4 above supports this conclusion.
Page 8 of 13
SGM’s worksheets for the Soil Observation Logs, Soil Texture by Feel and STA LTAR by Soil
Texture, Soil Structure and Treatment Level can be found in the Appendix.
4.0 Recommendations
An OWTS as a wastewater treatment system is suitable for this site. At a minimum The OWTS shall
have:
Hardware Specifications
Influent line 4” diameter
Cleanouts As required
Septic Tank 1000 gallons
Automatic Distribution Valve (ADV) Orenco V6406 or equivalent
Transport Lines and Distribution Laterals 1.5” diameter, schedule 40 PVC pipe
Distribution System Timed, Pressurized
Soil Treatment Area (STA) Unlined sand filter bed with sand media
Effluent from the structure will be conveyed through a 4-inch diameter service line, by gravity, to a
new septic tank. From the septic tank the effluent will be conveyed through 1-1/2 inch diameter
transport lines to an ADV, effluent flow will be pressurized. The ADV will direct the effluent flow to
each STA bed in an alternating manner. Effluent will be dispersed in each bed by 1-1/2 inch diameter
distribution laterals having 1/8 inch diameter orifices spaced at 4.0 feet on center.
The proposed development will have a three-bedroom single family residence. Per Table 6-2 of the
County’s OWTS Regulations the design flow rate will be 450 gpd (gallons per day).
Type of Property # Of Bedrooms Wastewater Flow per
Bedroom Design Flow (gpd)
Single Family
Residence 3 150 450
Location for the installation of the OWTS features will be as shown on sheet C1 and if installed as
shown, meet setback requirements of Table 7-1 of Reg43. The STA for the OWTS will be in the
southern portion of the property in the vicinity of test pits TP-1 and TP-2.
Sewer Pipe: Sewer service pipe shall be 4-inch SDR-35 PVC pipe installed with a minimum grade
of 1%, maximum grade of 8%. Minimum cover to be 42 inches, if minimum cover cannot be achieved
the pipe shall be insulated per the detail on sheet C2. Cleanouts are required:
1) Within 5 feet of the structure.
2) At spacing not to exceed 50 feet.
3) Upslope of two or more bends closer than 10 feet.
Transport lines shall be solid wall schedule 40 PVC pipe having an internal diameter of 1-1/2 inches.
Transport lines shall be placed at a minimum grade of 1 percent from the tank to the ADV, draining
back to the septic tank. Cover over the transport line shall be a minimum of 1 foot.
Transport lines from the ADV to the manifold shall be at a minimum grade of 1%, draining towards
the manifold, and shall also have a minimum covering of 1 foot.
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Distribution laterals shall be 1-1/2 inch diameter schedule 40 PVC pipe having 1/8 inch diameter
orifices drilled on 4-foot centers in the 12’Oclock position, with every fifth orifice drilled being in the
6’Oclock position.
All joints shall be solvent welded. All 90-degree bends shall be constructed using two 45-degree
fittings. The pipe shall be properly bedded per the typical trench detail presented on sheet C2.
Septic Tanks: One new 1,000-gallon septic tank with two bays is required. The tank must be on the
Colorado Department of Public Health and Environment’s accepted septic tank list. The tanks and
lids shall conform to current County OWTS regulations and be traffic rated. The tanks shall be
installed with insulated, watertight access risers having lids that can be secured. Risers shall meet
the tank manufacturer’s requirements for type and installation. The effluent filter handle shall extend
to within twelve inches of the lid.
The septic tank shall:
1) Be located down gradient of the structure.
2) Have a covering of no more than 4-feet in depth.
3) Be at a location accessible for pumping and maintenance.
The installer must coordinate with the Owner as to the elevation of the tank’s inlet invert stub out for
connection to the service line from the structure. A septic tank having a thicker cover than 4-feet will
not be approved.
The electrical control panels for the pump tanks shall be installed within line of site to the pump vault
riser. Controls and alarms shall be UL listed. The panel shall be weatherproof to protect against
adverse weather conditions.
Dosing Rate: Six doses approximately once every two hours during peak usage will accommodate
sewage to the STA from the septic tank. Seventy-five (75) gallons per dose will treat all 450 gallons
of sewage per day. One dose will drop the sewage height in the 35.39 square foot septic tank by 3.4.”
One dose will then be transported to one lateral at a time via an ADV. Each lateral has a treatment
area of 108 ft2 which is large enough to handle the specified LTAR of 0.8 gpd/ft2 with a lateral treating
a dose of 75 gallons (min 93.75 ft2 required).
Pumping System: The pump shall be an Orenco Model PF1005 with a Biotube Effluent Screen having
1/8-inch screen openings. The pump control system shall have 3 floats: 1) High Water Alarm Float,
2) Pump ON Float and 3) Pump OFF Float. The dosing volume to the sand filter STA shall be as
noted on the design drawings.
Automatic Distribution Valve (ADV): The ADV will be an Orenco V6404 or approved equal and shall
be installed per the manufacturer’s recommendations.
Soil Treatment Area: The soil treatment area is sized using criteria found in section 43.10 of Reg43
to treat 450 gpd, using beds for the soil treatment area, effluent application by pressure dosing and
chambers for the distribution media. The following table summarizes sizing of the STA.
Page 10 of 13
Gallons
per Day
(gpd)
LTAR
Method of
Application
Adjustment Factor
Distribution Media
Adjustment
Factor
STA
Size
(sf)
No. Infiltrators
(12sf/infiltrator)
450 0.8 1.0 0.7 432 36
The STA shall be installed as shown on sheet C1.
1. One bed with 36 infiltrators.
2. Bed shall be no wider than 12 feet, four infiltrators placed side-by-side.
3. Bed length shall be as shown on C1 but shall not exceed 60 feet.
4. The infiltrative surface shall be no deeper than four feet below grade.
5. Bed floors shall be level.
6. Chambers shall be placed per the manufacturer’s directions.
The STA configuration shown on sheet C1 may be modified or changed in the field if guidelines 1
through 6 are maintained and setbacks in section 2.5 can be met. Other setbacks per Table 7-1 of
Reg43 may be required, so review of Table 7-1 should be completed prior to relocating a STA bed.
In addition, the Engineer should be consulted prior to relocating the STA.
The STA shall have a final soil cover as described on Sheet C2. This may mean that the STA cover
will need to be 16-inches +/- when initially placed to allow for settlement over the freeze-thaw of a
winter season. The surface of the STA shall be seeded after installation of the system. A native,
upland seed mix should be used. These mixes do not require irrigation and develop a growth 10 to
15 inches high. No automatic sprinkler system shall be installed over the STA. Vehicular traffic and
livestock shall be kept off of the STA. No landscaping, impervious surfaces or plastic sheeting can
be installed over the STA, which will reduce its performance.
5.0 Installation Observations
The installation of the OWTS shall be observed by the design engineer. A final dosing observation
will be required prior to placing the OWTS into service. Our office shall be called at 970-945-1004 to
observe the installation at least three days in advance.
6.0 Operation and Preventative Maintenance Schedule
The goal of an operation and maintenance schedule is to observe the operation and perform minor
maintenance to the onsite wastewater system to allow for proper, long-term functioning of the system.
Septic tanks: The scum and sludge accumulation in the septic tanks shall be monitored yearly. Once
the cumulative scum or sludge thickness reaches 25% of the tank depth, the entire tank shall be
pumped. A pumping frequency of 1 to 3 years is expected at design flows. An alternative is a regular
pumping frequency of every 2 years.
Filter and Effluent Pumping System: The effluent filter at the septic tank discharge shall be cleaned
(hosed off) at the time of pumping or as needed. The effluent pumps shall be checked semi-annually
to ensure pumps are functioning properly. If the alarm sounds, the pumps, and floats shall be checked
and/or serviced immediately.
General: System users must realize that an on-site wastewater treatment system is different from
public sewer service. There are daily considerations, such as not putting plastic or other non-
biodegradable material into the system. Water use shall be monitored so that toilets are not allowed
Page 11 of 13
to leak when seals malfunction. Allowing fixtures to flow continuously to prevent water lines from
freezing is not acceptable. Although the proposed system can accommodate variable flows,
spreading water use over several hours and eliminating peak flows is recommended. To illustrate the
point, a malfunctioning toilet can discharge in excess of 1,000 GPD. Excessive daily loading could
flood and irreparably harm the OWTS.
SGM recommends against installation of a water softener. The chemical and hydraulic loading from
the backwash of a water softener would be damaging to the OWTS, so if a softener is installed, a
separate drywell shall be constructed for the backwash waste. No landscaping or plastic can be used
over the STA, which would reduce the performance of the STA. The design of the OWTS is based
on the treatment of domestic sewage only. Swimming pool or spa water is not to be discharged into
the OWTS. The proposed OWTS design is based on the regulatory flows noted in the attached
calculations. Increased flows may hydraulically or organically overload the OWTS, causing premature
failure.
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7.0 Limitations
Our investigation, layout, design, and recommendations are based on data provided by others. The
contents of this letter shall not serve as the basis for any third-party engineering design. If conditions
that are considerably different from those described in this report are encountered, SGM shall be
called to evaluate the conditions. If the proposed construction is changed, SGM shall be notified to
evaluate the effect of the changes on the OWTS. All construction shall be in accordance with the
Garfield County OWTS regulations. Pipe type and size, burial requirements, septic tank construction,
and other specifications, which are not depicted in our report, shall conform to the requirements of
the County OWTS regulations. The installer of the system shall be acceptable by the County’s
Environmental Health Department and shall have demonstrated knowledge of the County’s OWTS
regulations and requirements.
Appendix
Sheet C1
Sheet C2
NRCS Soils Map
NRCS Absorption Field Soils Data
USDA Textural Triangle
SGM Soil Observation Logs
SGM Soil Texture by Feel
TP-1 Trench Photo
TP-21 Trench Photo
OWTS Design Spreadsheet
Pump Selection
.31 FALL = 8132.19
8131
8131.24
8130
8129
8128
8127
8126
8131
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Title:
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
Natural
Resources
Conservation
Service
October 28, 2022
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://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
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 Web Soil Survey, the site for 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
2
alternative means 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.
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Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................12
Map Unit Descriptions........................................................................................12
Rifle Area, Colorado, Parts of Garfield and Mesa Counties............................14
19—Cochetopa-Jerry complex, 25 to 50 percent slopes............................14
Soil Information for All Uses...............................................................................16
Soil Reports........................................................................................................16
Sanitary Facilities............................................................................................16
Sewage Disposal.........................................................................................16
Soil Physical Properties..................................................................................18
Engineering Properties................................................................................18
References............................................................................................................22
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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
5
scientists classified and named the soils in the survey area, they compared the
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
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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.
8
9
Custom Soil Resource Report
Soil Map
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297340 297420 297500 297580 297660 297740
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 150 300 600 900
Feet
0 45 90 180 270
Meters
Map Scale: 1:3,100 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
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
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
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 map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
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 15, Sep 6, 2022
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 25, 2021—Sep
5, 2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
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MAP LEGEND MAP INFORMATION
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
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11
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
19 Cochetopa-Jerry complex, 25 to
50 percent slopes
38.8 100.0%
Totals for Area of Interest 38.8 100.0%
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 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.
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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.
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Rifle Area, Colorado, Parts of Garfield and Mesa Counties
19—Cochetopa-Jerry complex, 25 to 50 percent slopes
Map Unit Setting
National map unit symbol: jnxg
Elevation: 7,000 to 9,500 feet
Frost-free period: 45 to 75 days
Farmland classification: Not prime farmland
Map Unit Composition
Cochetopa and similar soils:50 percent
Jerry and similar soils:40 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Cochetopa
Setting
Landform:Mountainsides
Landform position (three-dimensional):Mountainflank
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Alluvium derived from sandstone and shale and/or alluvium
derived from basalt
Typical profile
H1 - 0 to 21 inches: loam
H2 - 21 to 30 inches: stony clay loam
H3 - 30 to 60 inches: stony clay
Properties and qualities
Slope:25 to 50 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: High
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
Available water supply, 0 to 60 inches: Moderate (about 8.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7e
Hydrologic Soil Group: C
Ecological site: R048AY238CO - Brushy Loam
Hydric soil rating: No
Description of Jerry
Setting
Landform:Mountainsides
Landform position (three-dimensional):Mountainflank
Down-slope shape:Convex
Across-slope shape:Convex
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Parent material:Alluvium derived from sandstone and shale and/or alluvium
derived from basalt
Typical profile
H1 - 0 to 3 inches: stony loam
H2 - 3 to 40 inches: cobbly clay loam
H3 - 40 to 60 inches: cobbly clay
Properties and qualities
Slope:25 to 50 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Very high
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
Available water supply, 0 to 60 inches: Moderate (about 8.1 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7e
Hydrologic Soil Group: C
Ecological site: R048AY238CO - Brushy Loam
Hydric soil rating: No
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Soil Information for All Uses
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.
Sanitary Facilities
This folder contains a collection of tabular reports that present soil interpretations
related to sanitary facilities. The reports (tables) include all selected map units and
components for each map unit, limiting features and interpretive ratings. Sanitary
facilities interpretations are tools designed to guide the user in site selection for the
safe disposal of sewage and solid waste. Example interpretations include septic
tank absorption fields, sewage lagoons, and sanitary landfills.
Sewage Disposal
This table shows the degree and kind of soil limitations that affect septic tank
absorption fields and sewage lagoons. 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).
16
Septic tank absorption fields are areas in which effluent from a septic tank is
distributed into the soil through subsurface tiles or perforated pipe. Only that part of
the soil between depths of 24 and 72 inches or between a depth of 24 inches and a
restrictive layer is evaluated. The ratings are based on the soil properties that affect
absorption of the effluent, construction and maintenance of the system, and public
health. Saturated hydraulic conductivity (Ksat), depth to a water table, ponding,
depth to bedrock or a cemented pan, and flooding affect absorption of the effluent.
Stones and boulders, ice, and bedrock or a cemented pan interfere with installation.
Subsidence interferes with installation and maintenance. Excessive slope may
cause lateral seepage and surfacing of the effluent in downslope areas.
Some soils are underlain by loose sand and gravel or fractured bedrock at a depth
of less than 4 feet below the distribution lines. In these soils the absorption field may
not adequately filter the effluent, particularly when the system is new. As a result,
the ground water may become contaminated.
Sewage lagoons are shallow ponds constructed to hold sewage while aerobic
bacteria decompose the solid and liquid wastes. Lagoons should have a nearly level
floor surrounded by cut slopes or embankments of compacted soil. Nearly
impervious soil material for the lagoon floor and sides is required to minimize
seepage and contamination of ground water. Considered in the ratings are slope,
saturated hydraulic conductivity (Ksat), depth to a water table, ponding, depth to
bedrock or a cemented pan, flooding, large stones, and content of organic matter.
Saturated hydraulic conductivity (Ksat) is a critical property affecting the suitability
for sewage lagoons. Most porous soils eventually become sealed when they are
used as sites for sewage lagoons. Until sealing occurs, however, the hazard of
pollution is severe. Soils that have a Ksat rate of more than 14 micrometers per
second are too porous for the proper functioning of sewage lagoons. In these soils,
seepage of the effluent can result in contamination of the ground water. Ground-
water contamination is also a hazard if fractured bedrock is within a depth of 40
inches, if the water table is high enough to raise the level of sewage in the lagoon,
or if floodwater overtops the lagoon.
A high content of organic matter is detrimental to proper functioning of the lagoon
because it inhibits aerobic activity. Slope, bedrock, and cemented pans can cause
construction problems, and large stones can hinder compaction of the lagoon floor.
If the lagoon is to be uniformly deep throughout, the slope must be gentle enough
and the soil material must be thick enough over bedrock or a cemented pan to
make land smoothing practical.
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.
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Report—Sewage Disposal
[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]
Sewage Disposal–Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil name Pct. of
map unit
Septic tank absorption fields Sewage lagoons
Rating class and limiting
features
Value Rating class and limiting
features
Value
19—Cochetopa-Jerry complex,
25 to 50 percent slopes
Cochetopa 50 Very limited Very limited
Slow water movement 1.00 Slope 1.00
Slope 1.00 Seepage 0.53
Jerry 40 Very limited Very limited
Slow water movement 1.00 Slope 1.00
Slope 1.00 Large stones 1.00
Large stones 0.36
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.
Engineering Properties
This table gives the engineering classifications and the range of engineering
properties for the layers of each soil in the survey area.
Hydrologic soil group is a group of soils having similar runoff potential under similar
storm and cover conditions. The criteria for determining Hydrologic soil group is
found in the National Engineering Handbook, Chapter 7 issued May 2007(http://
directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=17757.wba).
Listing HSGs by soil map unit component and not by soil series is a new concept for
the engineers. Past engineering references contained lists of HSGs by soil series.
Soil series are continually being defined and redefined, and the list of soil series
names changes so frequently as to make the task of maintaining a single national
list virtually impossible. Therefore, the criteria is now used to calculate the HSG
using the component soil properties and no such national series lists will be
Custom Soil Resource Report
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maintained. All such references are obsolete and their use should be discontinued.
Soil properties that influence runoff potential are those that influence the minimum
rate of infiltration for a bare soil after prolonged wetting and when not frozen. These
properties are depth to a seasonal high water table, saturated hydraulic conductivity
after prolonged wetting, and depth to a layer with a very slow water transmission
rate. Changes in soil properties caused by land management or climate changes
also cause the hydrologic soil group to change. The influence of ground cover is
treated independently. There are four hydrologic soil groups, A, B, C, and D, and
three dual groups, A/D, B/D, and C/D. In the dual groups, the first letter is for
drained areas and the second letter is for undrained areas.
The four hydrologic soil groups are described in the following paragraphs:
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.
Depth to the upper and lower boundaries of each layer is indicated.
Texture is given in the standard terms used by the U.S. Department of Agriculture.
These terms are defined according to percentages of sand, silt, and clay in the
fraction of the soil that is less than 2 millimeters in diameter. "Loam," for example, is
soil that is 7 to 27 percent clay, 28 to 50 percent silt, and less than 52 percent sand.
If the content of particles coarser than sand is 15 percent or more, an appropriate
modifier is added, for example, "gravelly."
Classification of the soils is determined according to the Unified soil classification
system (ASTM, 2005) and the system adopted by the American Association of
State Highway and Transportation Officials (AASHTO, 2004).
The Unified system classifies soils according to properties that affect their use as
construction material. Soils are classified according to particle-size distribution of
the fraction less than 3 inches in diameter and according to plasticity index, liquid
limit, and organic matter content. Sandy and gravelly soils are identified as GW, GP,
GM, GC, SW, SP, SM, and SC; silty and clayey soils as ML, CL, OL, MH, CH, and
OH; and highly organic soils as PT. Soils exhibiting engineering properties of two
groups can have a dual classification, for example, CL-ML.
The AASHTO system classifies soils according to those properties that affect
roadway construction and maintenance. In this system, the fraction of a mineral soil
that is less than 3 inches in diameter is classified in one of seven groups from A-1
through A-7 on the basis of particle-size distribution, liquid limit, and plasticity index.
Soils in group A-1 are coarse grained and low in content of fines (silt and clay). At
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the other extreme, soils in group A-7 are fine grained. Highly organic soils are
classified in group A-8 on the basis of visual inspection.
If laboratory data are available, the A-1, A-2, and A-7 groups are further classified
as A-1-a, A-1-b, A-2-4, A-2-5, A-2-6, A-2-7, A-7-5, or A-7-6. As an additional
refinement, the suitability of a soil as subgrade material can be indicated by a group
index number. Group index numbers range from 0 for the best subgrade material to
20 or higher for the poorest.
Percentage of rock fragments larger than 10 inches in diameter and 3 to 10 inches
in diameter are indicated as a percentage of the total soil on a dry-weight basis. The
percentages are estimates determined mainly by converting volume percentage in
the field to weight percentage. Three values are provided to identify the expected
Low (L), Representative Value (R), and High (H).
Percentage (of soil particles) passing designated sieves is the percentage of the soil
fraction less than 3 inches in diameter based on an ovendry weight. The sieves,
numbers 4, 10, 40, and 200 (USA Standard Series), have openings of 4.76, 2.00,
0.420, and 0.074 millimeters, respectively. Estimates are based on laboratory tests
of soils sampled in the survey area and in nearby areas and on estimates made in
the field. Three values are provided to identify the expected Low (L), Representative
Value (R), and High (H).
Liquid limit and plasticity index (Atterberg limits) indicate the plasticity
characteristics of a soil. The estimates are based on test data from the survey area
or from nearby areas and on field examination. Three values are provided to identify
the expected Low (L), Representative Value (R), and High (H).
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.
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Absence of an entry indicates that the data were not estimated. The asterisk '*' denotes the representative texture; other
possible textures follow the dash. The criteria for determining the hydrologic soil group for individual soil components is
found in the National Engineering Handbook, Chapter 7 issued May 2007(http://directives.sc.egov.usda.gov/
OpenNonWebContent.aspx?content=17757.wba). Three values are provided to identify the expected Low (L),
Representative Value (R), and High (H).
Engineering Properties–Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map unit symbol and
soil name
Pct. of
map
unit
Hydrolo
gic
group
Depth USDA texture Classification Pct Fragments Percentage passing sieve number—Liquid
limit
Plasticit
y index
Unified AASHTO >10
inches
3-10
inches
4 10 40 200
In L-R-H L-R-H L-R-H L-R-H L-R-H L-R-H L-R-H L-R-H
19—Cochetopa-Jerry
complex, 25 to 50
percent slopes
Cochetopa 50 C 0-21 Loam CL-ML,
CL
A-4 0- 0- 0 0- 0- 0 100-100
-100
100-100
-100
85-90-
95
60-68-
75
25-28
-30
5-8 -10
21-30 Stony clay loam CL A-6 10-28-
45
0-15- 30 75-83-
90
70-78-
85
65-75-
85
50-60-
70
30-33
-35
10-13-1
5
30-60 Stony clay CL A-7 10-28-
45
0-15- 30 75-83-
90
70-78-
85
65-75-
85
55-70-
85
40-45
-50
20-23-2
5
Jerry 40 C 0-3 Stony loam CL-ML,
SC-SM,
CL, SC
A-4 10-28-
45
0-15- 30 75-83-
90
70-78-
85
60-70-
80
45-55-
65
25-28
-30
5-8 -10
3-40 Cobbly clay loam CL A-6 0- 5- 10 15-30-
45
75-83-
90
70-78-
85
65-75-
85
50-60-
70
30-33
-35
10-13-1
5
40-60 Cobbly clay CL A-7 0-13- 25 15-30-
45
75-83-
90
70-78-
85
65-75-
85
55-70-
85
40-45
-50
15-20-2
5
Custom Soil Resource Report
21
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://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
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://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
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://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
22
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
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://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
23
USDA Textural Triangles
Soil Type, Texture, Structure and Percolation Rate Range Corresponding Long Term Acceptance Rate (LTAR)
in gallons per day per sq. ft.
Soil
Type USDA Soil Texture
USDA Soil
Structure-
Shape
USDA Soil
Structure-
Grade
Percolation
Rate (MPI)
Treatment
Level 1
Treatment
Level 2
Treatment
Level 2N
Treatment
Level 3
Treatment
Level 3N
0
Soil Type 1 with more
than 35% rock >2 mm
Soil Types 2-5 with more
than 50% rock (>2 mm)
--Single Grain <5
1.0
(minimum 3’
deep unlined
sand filter
required 2)
1.0
(minimum 2-foot deep unlined sand filter required 2)
1 Sand
Loamy Sand --Single Grain 5-15 0.80 1.25 1.25 1.40 1.40
2 Sandy Loam
Loam
Silt Loam
Prismatic
Blocky
Granular
Moderate
Strong 16-25 0.60 0.90 0.90 1.00 1.00
2A Sandy Loam
Loam
Silt Loam
Prismatic
Blocky
Granular
None
Weak
Massive 26-40 0.50 0.70 0.70 0.80 0.80
3 Sandy Clay Loam
Clay Loam
Silty Clay Loam
Prismatic
Blocky
Granular
Moderate
Strong 41-60 0.35 0.50 0.50 0.60 0.60
3A Sandy Clay Loam
Clay Loam
Silty Clay Loam
Prismatic
Blocky
Granular
None
Weak
Massive 61-75 0.30 0.40 0.40 0.50 0.50
4 Sandy Clay
Clay
Silty Clay
Prismatic
Blocky
Granular
Moderate
Strong 76-90 0.20 0.30 0.30 0.30 0.30
4A Sandy Clay
Clay
Silty Clay
Prismatic
Blocky
Granular
None
Weak
Massive 91-120 0.15 0.20 0.20 0.20 0.20
5 Soil Types 2-4A Platy
Weak
Moderate
Strong
121+0.10 0.15 0.15 0.15 0.15
Long-term Acceptance Rates
Based on CDPHE WQCC Regulation 43 Table 10.1 Soil Treatment Area Long-term Acceptance Rates by Soil Texture, Soil Structure, Percolation Rate and Treatment Level
10
20
30
40
50
60
70
80
90 10
20
30
40
50
60
70
80
90
100
102030405060708090100
100
Percent Sand
Per
c
e
n
t
C
l
a
y
P
e
r
c
e
n
t
S
i
l
t
Sand
Sandy Loam
Sandy Clay
Loam
Sandy
Clay Clay
Loam
Silty Clay
Loam
Silty
Clay
Clay
Silt Loam
Silt
Loam
SandLoamy
Textural
Triangle
Soil Type, Texture, Structure and Percolation Rate Range Corresponding Long Term Acceptance Rate (LTAR)
in gallons per day per sq. ft.
Soil
Type USDA Soil Texture
USDA Soil
Structure-
Shape
USDA Soil
Structure-
Grade
Percolation
Rate (MPI)
Treatment
Level 1
Treatment
Level 2
Treatment
Level 2N
Treatment
Level 3
Treatment
Level 3N
0
Soil Type 1 with more
than 35% rock >2 mm
Soil Types 2-5 with more
than 50% rock (>2 mm)
--Single Grain <5
1.0
(minimum 3’
deep unlined
sand filter
required 2)
1.0
(minimum 2-foot deep unlined sand filter required 2)
1 Sand
Loamy Sand --Single Grain 5-15 0.80 1.25 1.25 1.40 1.40
2 Sandy Loam
Loam
Silt Loam
Prismatic
Blocky
Granular
Moderate
Strong 16-25 0.60 0.90 0.90 1.00 1.00
2A Sandy Loam
Loam
Silt Loam
Prismatic
Blocky
Granular
None
Weak
Massive 26-40 0.50 0.70 0.70 0.80 0.80
3 Sandy Clay Loam
Clay Loam
Silty Clay Loam
Prismatic
Blocky
Granular
Moderate
Strong 41-60 0.35 0.50 0.50 0.60 0.60
3A Sandy Clay Loam
Clay Loam
Silty Clay Loam
Prismatic
Blocky
Granular
None
Weak
Massive 61-75 0.30 0.40 0.40 0.50 0.50
4 Sandy Clay
Clay
Silty Clay
Prismatic
Blocky
Granular
Moderate
Strong 76-90 0.20 0.30 0.30 0.30 0.30
4A Sandy Clay
Clay
Silty Clay
Prismatic
Blocky
Granular
None
Weak
Massive 91-120 0.15 0.20 0.20 0.20 0.20
5 Soil Types 2-4A Platy
Weak
Moderate
Strong
121+0.10 0.15 0.15 0.15 0.15
Long-term Acceptance Rates
Based on CDPHE WQCC Regulation 43 Table 10.1 Soil Treatment Area Long-term Acceptance Rates by Soil Texture, Soil Structure, Percolation Rate and Treatment Level
10
20
30
40
50
60
70
80
90 10
20
30
40
50
60
70
80
90
100
102030405060708090100
100
Percent Sand
Per
c
e
n
t
C
l
a
y
P
e
r
c
e
n
t
S
i
l
t
Sand
Sandy Loam
Sandy Clay
Loam
Sandy
Clay Clay
Loam
Silty Clay
Loam
Silty
Clay
Clay
Silt Loam
Silt
Loam
SandLoamy
Textural
Triangle
Soil Texture by Feel
Sandy Clay
Clay
Silty Clay
Forms a
ribbon 2” or
longer before
breaking
ClayType 4 or 4A
Soil Texture by Feel
Does the soil remain in a ball when squeezed?
What kind of ribbon does it form?
Add water Add dry soil
Is the soil too dry?
Is the soil too wet?
Yes
No Yes
No
Sand
Type 1
Loamy Sand
Type 1
No
Place soil in palm of hand. Add water drop-wise
and knead the soil into a smooth and plastic
consistency, like moist
putty.
Place ball of soil between thumb and forefinger,
gently pushing the soil between with the thumb,
squeezing it upward into a ribbon. Form a ribbon
of uniform thickness and width. Allow
ribbon to emerge and extend
over the forefinger,
breaking from
its own
weight.
Sandy Clay Loam
Clay Loam
Silty Clay Loam
Forms a 1 - 2”
ribbon before
breaking
Clay LoamType 3 or 3A
Sandy Loam
Loam
Silt Loam
Yes
Yes
Yes
Moisten pinch of soil
in palm and rub with
forefinger.Forms a weak
ribbon less
than 1” before
breaking
LoamType 2 or 2A
Does it fell
very gritty?
Does it feel
equally gritty
and smooth?
Does it feel
very smooth?
If platy structure then soil type 5
Does the soil form a ribbon?
Yes
No
Yes
Sandy Clay
Clay
Silty Clay
Forms a
ribbon 2” or
longer before
breaking
ClayType 4 or 4A
Soil Texture by Feel
Does the soil remain in a ball when squeezed?
What kind of ribbon does it form?
Add water Add dry soil
Is the soil too dry?
Is the soil too wet?
Yes
No Yes
No
Sand
Type 1
Loamy Sand
Type 1
No
Place soil in palm of hand. Add water drop-wise
and knead the soil into a smooth and plastic
consistency, like moist
putty.
Place ball of soil between thumb and forefinger,
gently pushing the soil between with the thumb,
squeezing it upward into a ribbon. Form a ribbon
of uniform thickness and width. Allow
ribbon to emerge and extend
over the forefinger,
breaking from
its own
weight.
Sandy Clay Loam
Clay Loam
Silty Clay Loam
Forms a 1 - 2”
ribbon before
breaking
Clay LoamType 3 or 3A
Sandy Loam
Loam
Silt Loam
Yes
Yes
Yes
Moisten pinch of soil
in palm and rub with
forefinger.Forms a weak
ribbon less
than 1” before
breaking
LoamType 2 or 2A
Does it fell
very gritty?
Does it feel
equally gritty
and smooth?
Does it feel
very smooth?
If platy structure then soil type 5
Does the soil form a ribbon?
Yes
No
Yes
TP-1
Observation Log and Photo
TP-2
Observation Log and Photo
OWTS Design Spreadsheet
O'Sullivan OWTS Design
Design Flow
(GPD)
# Bedrooms 3 450
Total Design Flows 450 gpd
SITE CRITERIA
Soil Type LTAR
1 x 0.8
2
2A
3
3A
4
4A
5
Soil Loading Rate =0.80 Based on Table 10.1
Soil Treatment Area = STA = Design Flow/LTAR 562.5
ft2
Size Adjustment Factors for Method of Application in STA
Type of Absorption
Area Method of Effluent Applcation
Gravity
Dosed (siphon
or pump)
Pressure
Dosed
Trench
Bed x
Size Adjustment Factors for Types of Distribution Media in STA
Category 1 -
Rock or Tire
Chips
Category 2 -
Other MFG
Media
Category 3 -
Chambers or
Enhanced
Media
Type of Absorption
Area X
Size Adjustment for Method of Application = 1
Size Adjustment for Type of Distribution = 0.7
Adjusted STA Size = 393.75
ft2
Number of Infiltrators =33
Number of Beds =1 ft
Bed Width =12 ft
Bed Length =32.8125 ft
Septic Tank Size = 1000 gallons
Pump Selection
Pump Selection for a Pressurized System - Single Family Residence Project
O'Sillivan
Parameters
Discharge Assembly Size
Transport Length Before Valve
Transport Pipe Class
Transport Line Size
Distributing Valve Model
Transport Length After Valve
Transport Pipe Class
Transport Pipe Size
Max Elevation Lift
Manifold Length
Manifold Pipe Class
Manifold Pipe Size
Number of Laterals per Cell
Lateral Length
Lateral Pipe Class
Lateral Pipe Size
Orifice Size
Orifice Spacing
Residual Head
Flow Meter
'Add-on' Friction Losses
1.50
6
40
1.50
6404
6.2
40
1.50
3
9
40
1.50
4
36
40
1.50
1/8
4
5
None
0
inches
feet
inches
feet
inches
feet
feet
inches
feet
inches
inches
feet
feet
inches
feet
Calculations
Minimum Flow Rate per Orifice
Number of Orifices per Zone
Total Flow Rate per Zone
Number of Laterals per Zone
% Flow Differential 1st/Last Orifice
Transport Velocity Before Valve
Transport Velocity After Valve
0.43
10
4.3
1
0.2
0.7
0.7
gpm
gpm
%
fps
fps
Frictional Head Losses
Loss through Discharge
Loss in Transport Before Valve
Loss through Valve
Loss in Transport after Valve
Loss in Manifold
Loss in Laterals
Loss through Flowmeter
'Add-on' Friction Losses
0.1
0.0
0.9
0.0
0.0
0.0
0.0
0.0
feet
feet
feet
feet
feet
feet
feet
feet
Pipe Volumes
Vol of Transport Line Before Valve
Vol of Transport Line After Valve
Vol of Manifold
Vol of Laterals per Zone
Total Vol Before Valve
Total Vol After Valve
0.6
0.7
0.9
3.8
0.6
5.4
gals
gals
gals
gals
gals
gals
4.3
8.9
gpm
feet
0 5 10 15
0
50
100
150
200
250
300
350
400
Net Discharge (gpm)
PumpData
PF1005 High Head Effluent Pump
10 GPM, 1/2HP
115/230V 1Ø 60Hz, 200V 3Ø 60Hz
PF1007 High Head Effluent Pump
10 GPM, 3/4HP
230V 1Ø 60Hz, 200V 3Ø 60Hz
PF1010 High Head Effluent Pump
10 GPM, 1HP
230V 1Ø 60Hz, 200V 3Ø 60Hz
Legend
System Curve:
Pump Curve:
Pump Optimal Range:
Operating Point:
Design Point: