HomeMy WebLinkAboutOWTS Preliminary Design Report and DesignCBO Inc.
129 Cains Lane
Carbondale, CO 81623
970.309.5259
carla.ostberg@gmail.com
December 30, 2024 Project No. C1930
Armando Mellin
woodwerxc@gmail.com
Onsite Wastewater Treatment System (OWTS) Preliminary Planning
607 Highlands Drive
Garfield County, Colorado
Armando,
CBO Inc. has visited the subject property to assess onsite wastewater treatment system (OWTS)
alternatives for a proposed 4-bedroom residence.
The 1.0-acre property is located in Glenwood Springs, in an area where OWTSs are necessary. The
legal description of the property is as follows:
Section: 5 Township: 6 Range: 89 Subdivision: GLENWOOD HIGHLANDS EST AMD Lot: 4 AS PER
AMENDED FINAL PLAT RECEPTION NO. 963988 1 ACRE Parcel ID: 2185-051 -13 -004
EXISTING CONDITIONS The property is currently un developed . A 4-bedroom residence is proposed.
The property will be served potable water from a community water system. The water line will enter the
property from the subdivision road to the north of the proposed residence. The water line will not come
within 25-feet of any OWTS component.
We researched other wells in the area from the Colorado Division of Water Resources website and found
a well to the south, but it is greater than 100-feet from the southern property line .
The proposed soil treatment area (STA) will be located to the southwest of the proposed residence.
SOILS
We have researched soils in the area through USGS Web Soil Survey. The report is enclosed. The area of
the proposed STA is identified by map unit symbol 58. The map unit name is Potts-Ildefonso complex, 12 to
25% slopes. Typical soil profile horizons are described as loam (varying from clay loam to very stony
loam).
The subsurface was investigated by HP Geotech, Project No.109 266A and is documented in a report dated
September 16, 2009 (enclosed). One Profile Pit was excavated and three percolation tests were performed.
Results of the percolation tests were 20 minutes per inch (MPI), 12 MPI, and 10 MPI. A sample was taken
from the Profile Pit between 4 and 5-feet below grade. Soils consisted of 0% gravel, 33% sand, 44% silt,
and 23% clay.
Page 2
The gradation and percolation rates are consistent with Soil Type 2, Loam. For purposes of preliminary
planning, we will use a long-term acceptance rate (LTAR) of 0.6 gallons per square foot for sizing
the STA.
A visual and tactile evaluation of two soil profile test pits excavations must be conducted prior to finalizing
the OWTS design.
PRELMINARY OWTS DESIGN
Design Calculations:
3 bedrooms x 75 GPD/person x 2 ppl/bedroom + 75 GPD (4th Bedroom) = 525 GPD
525 GPD / 0.6 gal/SF = 875 SF x 1.0 (gravity trenches) x 0.7 (chambers) = 613 SF
613 SF / 12 SF/chamber = min. 52 ‘Quick 4’ chambers
The proposed OWTS will accommodate 4-bedrooms in the residence. A design flow of 525 GPD will be
used.
The proposed OWTS may consist of a minimum 1250-gallon, two-compartment septic tank with an
Orenco® Biotube Effluent Filter. Effluent may gravity flow to a distribution box and then to four gravelless
chamber trenches, each trench consisting of 13 ‘Quick 4’ Infiltrator® chambers for a total of 52 chambers
and 624 square feet of infiltrative area.
Other design alternatives and/or technologies may be considered pending site-specific soil testing.
Please call with questions.
Sincerely,
CBO Inc.
Carla Ostberg, MPH, REHS
Soil Map—Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/30/2024
Page 1 of 3
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298890 298920 298950 298980 299010 299040 299070 299100 299130 299160 299190
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,440 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: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
Survey Area Data: Version 17, Aug 29, 2024
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
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Soil Map—Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/30/2024
Page 2 of 3
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
34 Ildefonso stony loam, 25 to 45
percent slopes
3.7 34.6%
58 Potts-Ildefonso complex, 12 to
25 percent slopes
6.7 62.9%
66 Torriorthents-Camborthids-
Rock outcrop complex,
steep
0.3 2.5%
Totals for Area of Interest 10.7 100.0%
Soil Map—Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/30/2024
Page 3 of 3
Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
58—Potts-Ildefonso complex, 12 to 25 percent slopes
Map Unit Setting
National map unit symbol: jnyv
Elevation: 5,000 to 6,500 feet
Farmland classification: Not prime farmland
Map Unit Composition
Potts and similar soils:60 percent
Ildefonso and similar soils:30 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Potts
Setting
Landform:Mesas, alluvial fans, valley sides
Down-slope shape:Convex, linear
Across-slope shape:Convex, linear
Parent material:Alluvium derived from basalt and/or alluvium
derived from sandstone and shale
Typical profile
H1 - 0 to 4 inches: loam
H2 - 4 to 28 inches: clay loam
H3 - 28 to 60 inches: loam
Properties and qualities
Slope:12 to 25 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 high (0.20 to 0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water supply, 0 to 60 inches: High (about 10.3 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: C
Ecological site: R048AY306UT - Upland Loam (Wyoming Big
Sagebrush)
Hydric soil rating: No
Map Unit Description: Potts-Ildefonso complex, 12 to 25 percent slopes---Rifle Area, Colorado,
Parts of Garfield and Mesa Counties
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/30/2024
Page 1 of 2
Description of Ildefonso
Setting
Landform:Alluvial fans, valley sides, mesas
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Alluvium derived from basalt and/or alluvium
derived from sandstone and shale
Typical profile
H1 - 0 to 8 inches: stony loam
H2 - 8 to 60 inches: very stony loam
Properties and qualities
Slope:12 to 25 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water
(Ksat):Moderately high to high (0.60 to 6.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:35 percent
Maximum salinity:Nonsaline to slightly saline (0.0 to 4.0
mmhos/cm)
Available water supply, 0 to 60 inches: Low (about 5.1 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: A
Ecological site: R034BY330UT - Upland Stony Loam (Pinyon-Utah
Juniper)
Hydric soil rating: No
Data Source Information
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Survey Area Data: Version 17, Aug 29, 2024
Map Unit Description: Potts-Ildefonso complex, 12 to 25 percent slopes---Rifle Area, Colorado,
Parts of Garfield and Mesa Counties
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/30/2024
Page 2 of 2
4,514
752.3
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3,5081:
Feet5850
Legend
292
Notes
Location
585
Date Prepared: 12/30/2024 10:59:03 AM
Well Constructed
Final Permit
County
Superfund Sites
Gar eld County, CO
Developed by
Account
Number
R312188
Parcel Number 218505113004
Acres 1
Land SqFt 0
Tax Area 031
Mill Levy 74.4320
Physical
Address
607 HIGHLANDS DR
GLENWOOD SPRINGS 81601
Owner Address MELLIN, ARMANDO
125 CENTER DRIVE #11
GLENWOOD SPRINGS CO
81601
Total Actual
Value
$250,000 Last 2 Sales
Date Price
4/19/2024 $271,000
6/20/2022 $265,000
Date created: 12/30/2024
Last Data Uploaded: 12/30/2024 2:08:37 AM
230 ft
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