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GARFIELD COUNTY OWTS REPORT
1708 COUNTY ROAD 121
CARBONDALE, CO 81623
October 2021
Max Weiss, E.I.
Terry Bendetti, P.E.
Rick Barth, P.E.
Prepared by
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004
970.945.5948 fax
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1708 COUNTY ROAD 121
CARBONDALE, COLORADO
“I hereby affirm that this report for the Onsite Wastewater Treatment System (OWTS) for 1708
County Road 121, Carbondale, 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.
SGM Project # 2016-262.005
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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 Error! Bookmark not defined.
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
5.0 Installation Observations 11
6.0 Operation and Preventative Maintenance Schedule 11
7.0 Limitations 12
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Appendix
OWTS Plan Sheet 1
OWTS Detail Sheet 2
NRCS Soils Map
NRCS Absorption Field Soils Data
USDA Textural Triangle
SGM Soils Observation Logs
SGM Soil Texture by Feel
TP-1 Trench Photo
TP-2 Trench Photo
FEMA FIRM Flood Insurance Rate Map
OWTS Design Spreadsheet
Pump Selection
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1.0 Introduction
A private, four-bedroom residence, is planned to be built on Buck Point Ranch. 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:
• Rick Barth - PE/NAWT Certified Designer
• Terry Bendetti - PE/CPOW Certified Competent Technician/NAWT Certified Designer
• Max Weiss - EI/CPOW Certified Competent Technician
2.0 Preliminary Investigation
2.1 Property Information
Physical Address: 1708 County Road 121, Carbondale, Colorado.
Legal Description: Section 32 Township: 6 Range: 87. Garfield County Account No. R084548,
Parcel 218932200033.
Existing Structures: Presently, the site is an empty lot with historic pasture and native land uses.
Domestic Water: On OWTS Plan Sheet 1, there is a proposed well in the northwest corner, that
will be located greater than the minimum setback requirement of 100 feet, Table 7-1 of Reg43.
There is no existing well.
2.2 Public Health Agency Records
Search of Garfield County’s Public Records did not reveal existing documents to indicate an
existing OWTS is permitted for the subject property.
2.3 Topography
Existing topography in the vicinity of the OWTS slopes from northeast towards the southwest at
grades of between 6.0 to 31.0 percent. The grades where the STA will be located at range from
6.0 to 16.0 percent. The slope shape is convex-convex (V-V). 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 units 59-Iyers loam and 67 Jerry-
Millerlake loams. Iyers has grades of between 6 to 25 percent, which does agree with field
observation. Jerry-Millerlake has grades between 25 to 45 percent, which also agrees with field
observations.
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2.5 Location of Physical Features
Physical features on the subject property that will require minimum horizontal setbacks are shown
in the following Table. This table comes from Table 7-1 in CO Reg. 43. All distances are in feet.
All setback will be met without amendment.
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: There are no easements on this property.
b. Floodplain Maps: According to FEMA flood panel 0802051500B there is no high of flooding
in this area. It is outside of any flood zone. This location is shown in the appendices.
The landscape position for the STA is considered summit and will not be impacted by stormwater
drainage. The slope shape is convex – convex (VV) towards the southwest.
2.7 Natural and Cultural Features
No natural or cultural features were identified in the site reconnaissance.
2.8 Current and Historic Land Use
The subject property is in Garfield County’s rural zone district. Current and historic land use has
been private, its future use is expected to also be private. The zoning for this property is
irrigation/agricultural.
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 21, 2021. 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, and approximate locations are shown on OWTS Plan Sheet 2. Visual
evaluation of all test pits was conducted under adequate light conditions, with the soil being in an
unfrozen state.
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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 shown on the attached map. All test pits were excavated to an approximate depth
of 8 feet. Observations of the excavated test pits show:
Test Pit TP-1
DEPTH Rock
>35% Texture Structure Grade Consistency
0”-78” Yes (40%) Sandy Clay
Loam Granular Weak Firm
78”-96” Yes (40%) Sandy
Loam
Granular Weak Loose
Test Pit TP-2
DEPTH Rock
>35% Texture Structure Grade Consistency
0”-87” Yes (67%) Clay Loam Blocky Moderate Firm
87”-96” Yes (62%) Sandy
Loam
Single
Grain
Weak Loose
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 both test pits TP-1 and
TP-2 per CPOW’s methodology.
Gravels were present in samples TP-1 and TP-2, and was greater than 35 percent rock, therefore
Table 10 1A was used to determine the soil type and the applicable long term application rate
(LTAR) for this soil type.
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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-1 4.0 Yes Yes Moderate Gritty
TP-2 4.0 Yes Yes Weak Gritty
*Weak < 1 inch; Moderate 1-2 inches; Strong > 2 inches.
Results shown in the above table indicate a USDA soil classification of Sandy Clay Loam, type 3
or 3A for the soils sampled from TP-1; for the soils sampled from TP-2 the indication is the soil is
a Clay Loam, type 3 or 3A. Since the volume of gravel was greater than 35 percent in both test
pits, these are both type R soils. TP-1 being a type 3 or 3A soil with a gravel volume greater than
35 percent makes this a type R-1, option 1 soil. TP-2 being a type 3 or 3A soil with a gravel
volume greater than 35 percent makes this a type R-1, option 1.
To determine the proper soil type, 3 or 3A for the soils sampled from TP-1, the USDA soil structure
type and grade were used. The following Table shows the soil’s USDA structure type and grade
determined for the sample.
SAMPLE
USDA Soil
Structure
Type
USDA Soil
Structure
Grade
TP-1 Granular Moderate
TP-2 Blocky Moderate
Both soil types 3 and 3A can have a granular or blocky structure type, but only soil type 3 can
have a moderate soil structure grade. As such, the soil to receive the effluent waste is classified
as soil type 3. According to Table 10-1A, section 43.11.C.3.b.(2) of Garfield County Reg43, a
secondary sand media in an unlined sand filter, the LTAR is either .8 gpd/ft2 or LTAR for TL3,
whichever results in the larger area. A smaller LTAR will result in a larger area, and the receiving
soil has an TL3 LTAR of .65 gpd/ft2, therefore this will be the LTAR in designing the system.
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:
• 4” diameter influent line.
• Influent line cleanouts as required.
• A septic tank.
• A pressurized distribution system.
• An automatic distribution valve (ADV).
• 1-1/2” diameter transport lines and distribution laterals.
• A PVC manifold at each bed.
• A sand filter bed type STA.
• Category 3 distribution media in the STA.
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Baffled from the structure will be conveyed through a 4 inch diameter influent 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
the STA bed in a lateral 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 4 bedrooms and an occupancy of 7 people. Per Table 6-1 of
the County’s OWTS Regulations the design flow rate will be 525 gpd (gallons per day).
Residential
Wastewater Occupancy Wastewater Flow per
Person Design Flow (gpd)
Single-family
dwellings 7 75 525
Location for the installation of the OWTS features will be as shown on OWTS Plan Sheet 1 and if
installed as shown, meet setback requirements of Table 7-1 of Reg43. The STA for the OWTS will
be in the east portion of the property in the vicinity of test pits TP-1 and TP-2.
Sewer Pipe: Sewer influent pipe shall be 4-inch SDR-35 PVC pipe installed with a minimum grade
of 2%, maximum grade of 10%. Minimum cover to be 42 inches, if minimum cover cannot be achieved
the pipe shall be insulated per the detail on sheet OWTS Detail Sheet 2. 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 1-1/4 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 2 feet.
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 O’clock position, with every fifth orifice drilled being in the 6
O’clock 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 OWTS
Detail Sheet 2.
Septic Tanks: One new 1,250 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.
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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: Four doses every three hours during peak usage will accommodate sewage to the STA
from the septic tank. 131.25 gallons per dose will treat all 525 gallons of sewage per day. One dose
will drop the sewage height in the 56.25 square foot septic tank by 3.75”. One dose will then be
transported to one lateral at a time via an ADV. Each lateral has a treatment area of 204 ft2 which is
large enough to handle the specified LTAR of .65 gpd/ft2 with a lateral treating a dose of 131.25 gpd.
Pumping System: The pump shall be an Orenco Model PF205 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 525 gpd, using a bed for the soil treatment area, effluent application by pressure dosing and
a sand filter. The following table summarizes sizing of the STA.
Gallons
per Day LTAR STA
Size
# of
laterals
gpd sf
525 0.65 808 4
The STA shall be installed as shown on OWTS Plan Sheet 1.
1. One bed.
2. Dimensions of bed shall be 12 ft by 68 ft as shown on OWTS Plan Sheet 1.
3. The infiltrative surface shall be no greater than 3-feet from the surface.
4. Bed floors shall be level.
The STA configuration shown on OWTS Plan Sheet 1 may be modified or changed in the field if
guidelines 2 through 6 are maintained and setbacks in section 2.5 can be met. Other setbacks per
Table 7-1 of Reg 43 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 OWTS Plan Sheet 1. This may mean that the
STA cover will need to be 16-inches +/- when initially placed to allow for settlement over the freeze-
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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 and any appurtenances shallower than 24”. No landscaping,
impervious surfaces or plastic sheeting can be installed over the STA, which will reduce its
performance.
5.0 Installation Observations
Final 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
schedule an inspection of 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
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.
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Appendix
OWTS Plan Sheet 1
OWTS Detail Sheet 2
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
FEMA FIRM Flood Insurance Rate Map
OWTS Design Spreadsheet
Pump Selection
Graphic ScaleIn Feet: 1" = 20'0102040Title:ResidentialOWTSRevision#Dwg No.1708 County Road 121
Carbondale, Colorado 81623Job No.Drawn by:Date:File:QC:2013-493RLB/ME/JMW11.8.2021RBBuckPoint960-OWTS118 West Sixth Street, Suite 200Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Date By:C.2.008 0Of :PE:JSSPermit SetProject Milestone:
TopViewSectionView···*Service contracts available for maintenance*············Item #1250T-2CP-HH 1250 Gallon Top Seam - 2CP with High Head Pump···Title:OWTS DetailsRevision#Dwg No.1708 County Road 121
Carbondale, Colorado 81623Job No.Drawn by:Date:File:QC:2013-493RLB/ME09.09.2021RBBuckPoint960-OWTSDetails118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Date By:C.5.001 0Of :PE:JSSPermit SetProject Milestone:
9
Custom Soil Resource Report
Soil Map
4373800437382043738404373860437388043739004373920437394043738004373820437384043738604373880437390043739204373940316250 316270 316290 316310 316330 316350 316370 316390 316410 316430 316450 316470
316230 316250 316270 316290 316310 316330 316350 316370 316390 316410 316430 316450 316470
39° 29' 43'' N 107° 8' 13'' W39° 29' 43'' N107° 8' 3'' W39° 29' 38'' N
107° 8' 13'' W39° 29' 38'' N
107° 8' 3'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 15 30 60 90
Meters
Map Scale: 1:1,120 if printed on A landscape (11" x 8.5") 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: Aspen-Gypsum Area, Colorado, Parts of
Eagle, Garfield, and Pitkin Counties
Survey Area Data: Version 12, Sep 2, 2021
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 14, 2010—Nov 1,
2017
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
Custom Soil Resource Report
10
MAP LEGEND MAP INFORMATION
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
11
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
59 Iyers loam, 6 to 25 percent
slopes
3.0 79.6%
67 Jerry-Millerlake loams, 25 to 45
percent slopes
0.8 20.4%
Totals for Area of Interest 3.8 100.0%
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,
Custom Soil Resource Report
12
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
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Septic Tank Absorption Fields—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties
(1708 County Road 121, Carbondale, CO 81623)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/5/2021
Page 1 of 5437388043738904373900437391043739204373930437394043739504373960437397043739804373990437387043738804373890437390043739104373920437393043739404373950437396043739704373980316170316180316190316200316210316220316230316240316250316260316270316280316290316300316310316320316330316340316350
316170 316180 316190 316200 316210 316220 316230 316240 316250 316260 316270 316280 316290 316300 316310 316320 316330 316340 316350
39° 29' 45'' N 107° 8' 16'' W39° 29' 45'' N107° 8' 8'' W39° 29' 41'' N
107° 8' 16'' W39° 29' 41'' N
107° 8' 8'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 40 80 160 240
Feet
0 10 20 40 60
Meters
Map Scale: 1:842 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
Very limited
Somewhat limited
Not limited
Not rated or not available
Soil Rating Lines
Very limited
Somewhat limited
Not limited
Not rated or not available
Soil Rating Points
Very limited
Somewhat limited
Not limited
Not rated or not available
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: Aspen-Gypsum Area, Colorado, Parts of
Eagle, Garfield, and Pitkin Counties
Survey Area Data: Version 12, Sep 2, 2021
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 14, 2010—Nov 1,
2017
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.
Septic Tank Absorption Fields—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties
(1708 County Road 121, Carbondale, CO 81623)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/5/2021
Page 2 of 5
Septic Tank Absorption Fields
Map unit
symbol
Map unit name Rating Component
name (percent)
Rating reasons
(numeric
values)
Acres in AOI Percent of AOI
42 Fluvaquents, 0
to 10 percent
slopes
Very limited Fluvaquents
(90%)
Flooding (1.00)0.0 1.3%
Depth to
saturated zone
(1.00)
Seepage, bottom
layer (1.00)
Slow water
movement
(0.47)
59 Iyers loam, 6 to
25 percent
slopes
Very limited Iyers (85%)Slow water
movement
(1.00)
1.2 42.4%
Depth to bedrock
(1.00)
Slope (1.00)
67 Jerry-Millerlake
loams, 25 to
45 percent
slopes
Very limited Jerry (50%)Slope (1.00)1.6 56.3%
Slow water
movement
(1.00)
Millerlake (40%)Slope (1.00)
Slow water
movement
(1.00)
Totals for Area of Interest 2.8 100.0%
Rating Acres in AOI Percent of AOI
Very limited 2.8 100.0%
Totals for Area of Interest 2.8 100.0%
Septic Tank Absorption Fields—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and
Pitkin Counties
1708 County Road 121, Carbondale,
CO 81623
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/5/2021
Page 3 of 5
Description
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 60 inches 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.
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.
Septic Tank Absorption Fields—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and
Pitkin Counties
1708 County Road 121, Carbondale,
CO 81623
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/5/2021
Page 4 of 5
Rating Options
Aggregation Method: Dominant Condition
Aggregation is the process by which a set of component attribute values is
reduced to a single value that represents the map unit as a whole.
A map unit is typically composed of one or more "components". A component is
either some type of soil or some nonsoil entity, e.g., rock outcrop. For the
attribute being aggregated, the first step of the aggregation process is to derive
one attribute value for each of a map unit's components. From this set of
component attributes, the next step of the aggregation process derives a single
value that represents the map unit as a whole. Once a single value for each map
unit is derived, a thematic map for soil map units can be rendered. Aggregation
must be done because, on any soil map, map units are delineated but
components are not.
For each of a map unit's components, a corresponding percent composition is
recorded. A percent composition of 60 indicates that the corresponding
component typically makes up approximately 60% of the map unit. Percent
composition is a critical factor in some, but not all, aggregation methods.
The aggregation method "Dominant Condition" first groups like attribute values
for the components in a map unit. For each group, percent composition is set to
the sum of the percent composition of all components participating in that group.
These groups now represent "conditions" rather than components. The attribute
value associated with the group with the highest cumulative percent composition
is returned. If more than one group shares the highest cumulative percent
composition, the corresponding "tie-break" rule determines which value should
be returned. The "tie-break" rule indicates whether the lower or higher group
value should be returned in the case of a percent composition tie. The result
returned by this aggregation method represents the dominant condition
throughout the map unit only when no tie has occurred.
Component Percent Cutoff: None Specified
Components whose percent composition is below the cutoff value will not be
considered. If no cutoff value is specified, all components in the database will be
considered. The data for some contrasting soils of minor extent may not be in the
database, and therefore are not considered.
Tie-break Rule: Higher
The tie-break rule indicates which value should be selected from a set of multiple
candidate values, or which value should be selected in the event of a percent
composition tie.
Septic Tank Absorption Fields—Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and
Pitkin Counties
1708 County Road 121, Carbondale,
CO 81623
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/5/2021
Page 5 of 5
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 SandPercent ClayP
e
r
c
en
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 SandPercent ClayP
e
r
c
en
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
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 DITCH
Detterick Single Famility Residential OWTS Design
Design
Flow
(GPD)
# Bedrooms 4 525
Auxilliary Bldngs
Bath/Shower
Dishwasher
Kitchen Sink
w/Garbage Grinder
Laundry Washer
Lavatory
Water Closet (toilet)
Total Design Flows 525 gpd
SITE CRITERIA
Soil Type LTAR
1
2
2A
3 x 0.65
3A
4
4A
5
Soil Loading Rate =0.65 Based on Table 10.1 TL3 and note 3 on Table 10-1a
Soil Treatment Area = STA = Design Flow/LTAR 808
ft2
Bed Area Length 12 ft
Bed Area Width 68 ft
Septic Tank Size = 1250 gallons
Pump Selection for a Pressurized System - Single Family Residence Project
Buck Point Ranch
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
115
40
1.50
4404
6
40
1.50
14.5
1
40
1.50
4
68
40
1.50
1/8
2
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
35
15.3
1
3.5
2.4
2.4
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
0.7
1.7
4.4
0.1
0.0
0.4
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
12.2
0.6
0.1
7.2
12.2
7.9
gals
gals
gals
gals
gals
gals
15.3
26.8
gpm
feet
0 5 10 15 20 25 30
0
50
100
150
200
250
300
350
Net Discharge (gpm)
PumpData
PF2005 High Head Effluent Pump
20 GPM, 1/2HP
115/230V 1Ø 60Hz, 200V 3Ø 60Hz
Legend
System Curve:
Pump Curve:
Pump Optimal Range:
Operating Point:
Design Point: