HomeMy WebLinkAboutFile Documents.210 S West End St.0011-2021-BCHO (18)
DRAINAGE REPORT FOR
210 S WEST END
ASPEN, CO 81611
I hereby affirm that this report and the accompanying drawings for the analysis of 210 S
West End Drive, Aspen, Colorado was prepared under my direct supervision for the owners
thereof in accordance with the provisions of the City of Aspen Urban Runoff Management
Plan with proposed variances and exceptions listed thereto. I understand that it is the policy
of the City of Aspen that the City of Aspen does not and will not assume liability for drainage
facilities designed by others.
Permit #: 0011-2021-BCHO
August 04, 2021
Rick Barth, P.E. 36749
Prepared by
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004
970.945.5948 fax
08/10/2021
210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design i
DRAINAGE REPORT FOR
210 S WEST END
ASPEN, CO 81611
REVIEWED BY
RICK BARTH
SGM Project # 2020-474.001
I:\2020\2020-474-SackResidenceRenovation\001\E-Reports\SGM\Working Files\Sack-
Drainage-Report.docx
08/10/2021
210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design ii
TABLE OF CONTENTS
1.0 Existing Site 3
1.1 Description of Existing Site 3
1.2 Description of Existing Drainage 3
2.0 Proposed Project 3
3.0 Proposed Basins 4
3.1 Basin 1 4
3.2 Basin 2 4
3.3 Basin 3 4
3.4 Basin 4 5
3.5 Basin 5 5
3.6 Basin 6 5
4.0 Peak Flow Methodology 5
5.0 Water Quality Methodology 6
6.0 Maintenance 6
6.1 Pervious Pavers 6
6.2 Rain Garden 6
6.3 Dry well (Flo-Well) 7
7.0 Conclusion 7
LIST OF APPENDICES
Appendix A – Proposed Drainage Schematic & Tree Canopy Credits
Appendix B – Water Quality Capture Volume Calculations
Appendix C – Peak Flow Calculations – Proposed Conditions
Appendix D – Soil Study
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210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design 3
1.0 Existing Site
1.1 Description of Existing Site
The physical address of the project is 210 S West End, Aspen, Colorado and it is located on
parcel no. 2737-182-06-004. This parcel is approximately 9000 square feet and is owned by
West End Home LLC. The existing structure on the parcel is one building that serves as a
multi-unit (4-8). The project focuses on landscaping and entrance improvements and
changes to the inside and the addition of roof and balcony aspects while preserving access,
utilities, and most existing vegetation. The existing residence is 7602 square feet and has
three stories with a garage.
1.2 Description of Existing Drainage
Existing storm water runs off the existing house either as sheet flow or through gutters and
downspouts. Topography of the site suggests that the existing drainage patterns flow from
the east side of the property to the west side of the property. Some drainage moves north
and south but ultimately flows west once it reaches the gutter and alley. A previously
designed flo-well detention system was installed in the fall of 2020 and will be incorporated
into the design of the major classification project. There are no apparent erosive or runoff
issues (gullies, channels, etc.).
A web soil survey was performed and found the soils to be Uracca, moist-Mergel complex,
classified as Hydrologic Soil Group B will well-draining soils consisting of very cobbly sandy
clay loam to extremely cobbly loamy sand.
There is no existing offsite runoff that enters the property as upstream flows appear to be
properly directed to the CoA stormwater infrastructure. The property will not require
detention beyond the water quality capture volume (WQCV) as it exists within the City of
Aspen and can rely on the city’s stormwater infrastructure.
2.0 Proposed Project
The primary purpose of this project is to remodel the existing residence. Other
improvements include the addition of onsite snowmelt pavement and improving storm water
runoff quality. The proposed project is considered a major project as defined by the COA
Urban Runoff Management Plan (URMP) because more than 1000 square feet and 25% of
the site will be disturbed.
The proposed residential remodel will affect the main level, basement, and upper level.
Storm water quality improvements consist of 838 square feet of pervious pavers and 55.3
cubic feet of rain gardens. The pervious pavers will be located on the patios and walkways
around the property. Rain gardens are located on the west of the residence.
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210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design 4
3.0 Proposed Basins
The proposed site has 6 basins, as shown in Appendix A. Summary of the basins and
detailed calculations can be found in Appendix B. Storm water runoff will be routed to
designated BMPs for water quality treatment through a combination of grading and gutters
with downspouts. All proposed storm water runoff will discharge from the site as sheet flow
in a westerly direction to match historical flow patterns. Basins are detailed in the sections
that follow, with descriptions on how the required WQCV is treated by BMPs within the
basin. WQCV is calculated based on tree canopy credits, proposed rain garden volume, and
proposed pervious paver area.
3.1 Basin 1
Basin 1 is located on the northeast corner of the site, along the alley. This basin is 1571
square feet of which 1312 square feet is impervious. A 12.6 cubic foot flo-well detention with
4.7 cubic feet of aggregate volume (gravel) will be used to treat the WQCV for this basin.
This flo-well was designed by another engineering firm when the project was currently in a
Minor Development category. Grades were adjusted to better fit the overall grading scheme
and an overflow pipe was added to the design, directing water further downstream to Basin
6. See Appendix A for the proposed location of BMPs in this basin. This area is mostly the
north-eastern portion of the building and roof. Storm water will be routed from the roof and
driveway to the flo-well via roof drainage, gutter downspouts, and a trench drain in front of
the garage. Water infiltrates within the flo-well detention and an overflow pipe is connected
to direct excess water to a secondary flo-well in Basin 6. The need for the overflow and
second flo-well derives from the garage apron and driveway being in a sump condition.
Previous designs for the flo-well had the overflow directing back to the trench drains,
creating a circular flow path with no overflow route away from this basin.
3.2 Basin 2
Basin 2 is located on the eastern portion of the site. Storm water runoff will flow from roof
areas toward the east property boundary and ultimately west by means of an underdrain.
This basin is 1032 square feet of which 828 square feet is impervious. Pervious pavers will
be used to treat the WQCV, with remaining WQCV being treated by the rain gardens on the
west of the site. See Appendix A for the proposed location of BMPs in this basin. After water
infiltrates through the pavers and respective substrate, it enters the underdrain and is
directed to the rain garden.
3.3 Basin 3
Basin 3 is located on the southeast side of the site and will collect runoff from the southeast
portion of the roof. Storm water runoff will flow from roof areas toward the south property
boundary and ultimately west by means of an underdrain. This basin is 1688 square feet of
which 821 square feet is impervious. Pervious pavers will be used to treat the WQCV, with
remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A
for the proposed location of BMPs in this basin. After water infiltrates through the pavers and
respective substrate, it enters the underdrain and is directed to the rain garden.
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210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design 5
3.4 Basin 4
Basin 4 is located on the southwest side of the site and will collect runoff from the southwest
portion of the roof. Storm water runoff will flow from roof areas toward the south property
boundary and ultimately west by means of an underdrain. This basin is 2132 square feet of
which 709 square feet is impervious. Pervious pavers will be used to treat the WQCV, with
remaining WQCV being treated by the rain gardens on the west of the site. See Appendix A
for the proposed location of BMPs in this basin. After water infiltrates through the pavers and
respective substrate, it enters the underdrain and is directed to the rain garden.
3.5 Basin 5
Basin 5 is located on the west side of the site and will collect runoff from the west portion of
the roof. Storm water runoff will flow from roof areas toward the west property boundary by
means of surface flow and an underdrain This basin is 1516 square feet of which 829
square feet is impervious. Pervious pavers will be used to treat the WQCV, with remaining
WQCV being treated by the rain gardens on the west of the site. See Appendix A for the
proposed location of BMPs in this basin. After water infiltrates through the pavers and
respective substrate, it enters the underdrain and is directed to the rain garden.
3.6 Basin 6
Basin 6 is located on the northwest side of the site and will collect runoff from the northwest
portion of the roof. Storm water runoff will flow from roof areas toward the south by means of
gutter and surface flow. This basin is 1061 square feet of which 676 square feet is
impervious. Pervious pavers will be used to treat the WQCV, with remaining WQCV being
treated by the rain gardens on the west of the site. See Appendix A for the proposed
location of BMPs in this basin. After water infiltrates through the pavers and respective
substrate, it enters the underdrain and is directed to the rain garden.
4.0 Peak Flow Methodology
Peak flow methodology was not a determining factor for this site since all stormwater will be
treated for water quality and ultimately ending up in the City of Aspen stormwater
infrastructure. Pipe sizes were calculated to ensure they are sized appropriately to convey
the 100-year storm water. These sizing calculations can be seen below.
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210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design 6
5.0 Water Quality Methodology
The Required WQCV (cf) for each basin on the property was estimated from Figure 8.13 of
the URMP based on the basin imperviousness and basin area. Then WQCV credits were
estimated based on the proposed areas for pervious pavers and preserved tree canopy (see
further discussion of tree canopy credit below). All water quality treatment is based on the
instruction of section 8.4.1 in the URMP
The Tree Canopy Credit was calculated following the recommendations in section 8.4.1 of
the URMP. Detailed calculations for the Tree Canopy Credit can be found in Appendix C. In
addition, a map showing the designated trees and their canopy areas is shown in Appendix
B. Runoff from all impervious areas will be treated by directing the runoff to pervious pavers
and a rain garden. All proposed runoff will leave the property as sheet flow and will flow over
grass lawn located in the right of way before entering the curb and gutter system.
6.0 Maintenance
6.1 Pervious Pavers
The following maintenance recommendations were found in the Urban Drainage Flood Control
District USDCM: Volume 3 Storm water Quality (page 6-15 to 6-17) and will be used as a guide
for the maintenance of the proposed pervious pavers. An inspection of the condition and
observation of infiltration should be completed annually. The pavers will lose infiltration
capabilities over time and it is recommended to use ASTM C1707 Standard Test Method for
Infiltration Rate of In Place Pervious Concrete to measure the infiltration rate of the pavers. A
regenerative air or vacuumed sweeper should be used twice annually and after any significant
site work, like landscaping, is done. However, the timing of vacuum sweeping is variable based
on site conditions and biannual vacuuming may be more often than needed. Sand should never
be applied to the pavers for snow removal as this will decrease the permeability of the pavers.
The proposed pavers will have snowmelt capabilities, but if snow removal is necessary,
mechanical snow removal should be done. If the surface of the paver system ever becomes
completely clogged, remove and replacement of the first ½ to 1 inch of infill. The use of a push
broom is recommended for the replacement of infill.
6.2 Rain Garden
Annual inspection of the rain gardens should be taken to ensure that the material is not clogged
and inhibiting drainage. Inspection after large storms should also be taken to ensure that the
rain garden is draining as it should. Replacement and/or cleaning of the material should be
performed when it is observed that the rain garden is performing less than optimally in its
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210 S West End, Aspen, Colorado August 4, 2021
Drainage Report for Major Design 7
existing condition. Cleaning of the underdrain should be inspected annually and after large
storms that could cause debris to clog the pipes. Cleanouts have been provided to facilitate this
maintenance.
6.3 Dry well (Flo-Well)
Dry wells must be inspected and maintained yearly to remove sediment and debris that is
washed into them. A maintenance plan shall be submitted to the City in the Drainage Report
describing the maintenance schedule that will be undertaken by the owners of the new
residence or building. Minimum inspection and maintenance requirements include the
following:
• Inspect dry wells as annually and after every storm exceeding 0.5 inches.
• Dispose of sediment, debris/trash, and any other waste material removed from a dry well
at suitable disposal sites and in compliance with local, state, and federal waste regulations.
• Routinely evaluate the drain-down time of the dry well to ensure the maximum time of 24
hours are not being exceeded. If drain-down times are exceeding the maximum, drain the
dry well via pumping and clean out the percolation area (the percolation barrel may be
jetted to remove sediment accumulated in perforations). Consider drilling additional
perforations in the barrel. If slow drainage persists, the system may need to be replaced.
7.0 Conclusion
The proposed BMPs (grass buffer, pervious pavers, and rain gardens) are expected to treat
100% of the required WQCV at the 210 S West End project with room to spare. With proper
maintenance and installation, these BMPs will meet the criteria outlined in the City of
Aspen’s current Urban Runoff Management Plan.
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1
1571 24.0
2
1032 14.8
3
1688 13.4
4
2132 12.4
5
1516 13.5
6
1061 11.1
Basin
Area WQCV
sqft cuft
Graphic Scale
In Feet: 1" = 5'
0 3 5 10
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08.04.2021
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08/10/2021
Input
Calculation
Sub Basin Basin
Name Total Area Imp.
Area
Imperv-
iousness
Req'd WQCV
(depth)
Req'd WQCV
(vol.)Decid. Area Conif. Area
Perv. Paver
Area
No Inf.
Paver Depth
No Inf.
Paver
Void
Vol.
Grass
Buffer
Area
Rain
Garden /
Flo-Well
Volume
Perv. Paver
Ratio
Grass
Buffer
Ratio
Canopy
Credit
Grass Buffer
Credit
Eff. Imp.
Area
Eff.
Imperv-
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s
Eff.
WQCV
(depth)
Net
WQCV
(#)(sq. ft.)(sq. ft.)(%)(in)(cu. ft.)(sq. ft.)(sq. ft.)(sq. ft.)(ft)(cu. ft.)(sq. ft.)(cu. ft.)(sq. ft.)(sq. ft.)(sq. ft.)(%)(in)(cu. ft.)
1 NE 1571 1312 84%0.18 24.0 0.0 0.0 113.3 0.5 18.9 0 18 2 1 0.0 0 1312 83.5%0.183 -13.24
2 East 1032 828 80%0.17 14.8 0.0 0.0 187.0 0.5 31.2 0 0 2 1 0.0 0 828 80.2%0.172 -16.39
3 SE 1688 821 49%0.10 13.4 305.0 462.0 154.0 0.5 25.7 0 0 2 1 184.4 0 637 37.7%0.077 -14.83
4 SW 2132 709 33%0.07 12.4 443.0 295.0 134.0 0.5 22.3 0 0 2 1 155.0 0 554 26.0%0.058 -12.03
5 West 1516 829 55%0.11 13.5 0.0 183.0 150.0 0.5 25.0 0 0 2 1 54.9 0 774 51.1%0.100 -12.41
6 NW 1061 676 64%0.13 11.1 0.0 154.0 99.5 0.5 16.6 0 37 2 1 46.2 0 630 59.4%0.116 -43.33
Total 9000 5175 58%0.8 89 748 1094 838 3.0 139.6 0 55.3 440 0.0 4735 56%0.71 -112.2
Legend
08/10/2021
Major Drainage Report Calculations
3 3 3 3
Jordan Kehoe 4 4 4 4
7 7 7 7
Condition Developed Historic 1 - Dev 1 - Hist 2 - Dev 2 - Hist 3 - Dev 3 - Hist 4 - Dev 4 - Hist 5 - Dev 5 - Hist 6 - Dev 6 - Hist
Area / ft^2 9000 9000 1571 1571 1032 1032 1688 1688 2132 2132 1516 1516 1061 1061
Aimp / ft^2 5175 180 1312.0 31.4 828.0 20.6 821.0 33.8 709.0 42.6 829.0 30.3 676.0 21.2
Soil Type B B B B B B B B B B B B B B
Lo / ft 25 25 25 25 25 25 25 25 25 25 25 25 25 25
So / ft/ft 0.02 0.06 0.02 0.06 0.02 0.06 0.02 0.06 0.02 0.06 0.02 0.06 0.02 0.06
Lf / ft 25 25 25 25 25 25 25 25 25 25 25 25 25 25
Sf / ft/ft 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02
K 10 10 10 10 10 10 10 10 10 10 10 10 10 10
L / ft 0 0 0 0 0 0 0 0 0 0 0 0 0 0
% Imp 57.50%2.00%83.60%2.00%80.30%2.00%48.70%2.00%33.30%2.00%54.70%2.00%63.80%2.00%
C5 0.47 0.01 0.71 0.01 0.68 0.01 0.39 0.01 0.26 0.01 0.45 0.01 0.53 0.01
C10 0.52 0.07 0.73 0.07 0.71 0.07 0.45 0.07 0.33 0.07 0.50 0.07 0.57 0.07
C100 0.70 0.44 0.82 0.44 0.80 0.44 0.65 0.44 0.58 0.44 0.68 0.44 0.73 0.44
To /min 4.52 5.44 2.82 5.44 3.04 5.44 5.08 5.44 6.03 5.44 4.70 5.44 4.11 5.44
Vf /ft/sec 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41 1.41
Tf /min 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29
Tc,i /min 5.00 5.73 5.00 5.73 5.00 5.73 5.37 5.73 6.33 5.73 5.00 5.73 5.00 5.73
TR / min 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14
Td / min 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14 5.00 10.14
I10 / in/hr 3.96 2.90 3.96 2.90 3.96 2.90 3.96 2.90 3.96 2.90 3.96 2.90 3.96 2.90
I100 / in/hr 6.33 4.64 6.33 4.64 6.33 4.64 6.33 4.64 6.33 4.64 6.33 4.64 6.33 4.64
Q10 / cfs 0.43 0.04 0.10 0.01 0.07 0.01 0.07 0.01 0.06 0.01 0.07 0.01 0.06 0.01
Q100 / cfs 0.91 0.42 0.19 0.07 0.12 0.05 0.16 0.08 0.18 0.10 0.15 0.07 0.11 0.05
Return Period P1 / in/hr
2-yr 0.47
5-yr 0.64
10-r 0.77
25-yr 0.95
50-yr 1.09
100-yr 1.23
IDF for Aspen, CO
Site Basins
From Table 2.2 of COA URMP (page 2-2), Rainfall Intensity-Duration-
Frequency (IDF) in Aspen, CO
Wednesday, August 4, 2021
08/10/2021
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
Aspen-Gypsum Area,
Colorado, Parts of Eagle,
Garfield, and Pitkin
Counties
Natural
Resources
Conservation
Service
February 16, 2021
08/10/2021
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 08/10/2021
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.
3 08/10/2021
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions.........................................................................................11
Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin
Counties...................................................................................................13
107—Uracca, moist-Mergel complex, 1 to 6 percent slopes, extremely s..13
References............................................................................................................15
4 08/10/2021
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 08/10/2021
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.
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Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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Custom Soil Resource Report
Soil Map
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343348 343356 343364 343372 343380 343388 343396
343348 343356 343364 343372 343380 343388
39° 11' 17'' N
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 15 30 60 90
Feet
0 4 9 18 27
Meters
Map Scale: 1:318 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
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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 11, Jun 5, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Data not available.
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.
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Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
107 Uracca, moist-Mergel complex,
1 to 6 percent slopes,
extremely s
0.3 100.0%
Totals for Area of Interest 0.3 100.0%
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,
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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.
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Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin
Counties
107—Uracca, moist-Mergel complex, 1 to 6 percent slopes, extremely s
Map Unit Setting
National map unit symbol: jq4g
Elevation: 6,800 to 8,400 feet
Mean annual precipitation: 16 to 19 inches
Mean annual air temperature: 40 to 43 degrees F
Frost-free period: 75 to 95 days
Farmland classification: Not prime farmland
Map Unit Composition
Uracca, moist, and similar soils:50 percent
Mergel and similar soils:40 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Uracca, Moist
Setting
Landform:Structural benches, valley sides, alluvial fans
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium derived from igneous and metamorphic rock
Typical profile
H1 - 0 to 8 inches: cobbly sandy loam
H2 - 8 to 15 inches: very cobbly sandy clay loam
H3 - 15 to 60 inches: extremely cobbly loamy sand
Properties and qualities
Slope:1 to 6 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
(0.20 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Available water capacity:Very low (about 2.6 inches)
Interpretive groups
Land capability classification (irrigated): 6s
Land capability classification (nonirrigated): 6s
Hydrologic Soil Group: B
Ecological site: R048AY237CO - Stony Loam
Other vegetative classification: Stony Loam (null_82)
Hydric soil rating: No
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Description of Mergel
Setting
Landform:Valley sides, alluvial fans, structural benches
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Glacial outwash
Typical profile
H1 - 0 to 8 inches: cobbly loam
H2 - 8 to 20 inches: very cobbly sandy loam
H3 - 20 to 60 inches: extremely stony sandy loam
Properties and qualities
Slope:1 to 6 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Very 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:10 percent
Available water capacity:Low (about 3.3 inches)
Interpretive groups
Land capability classification (irrigated): 4s
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: A
Ecological site: R048AY237CO - Stony Loam
Other vegetative classification: Stony Loam (null_82)
Hydric soil rating: No
Minor Components
Other soils
Percent of map unit:10 percent
Hydric soil rating: No
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References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://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
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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
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