HomeMy WebLinkAboutReports - Drainage - 07/17/2025
Final Drainage Report
For
Willox Farms
Dated: July 17, 2025
Engineer:
EPS Group
301 N. Howes Street, Suite 100
Fort Collins, Colorado 80521
(970) 221-4158
Project No. 987-012
Date: July 2025
EPS Group
Fort Collins | Greeley
970.221.4158
epsgroupinc.com
WILLOX FARM
TABLE OF CONTENTS
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TABLE OF CONTENTS
1.0 Engineer Certification .....................................................................................................3
2.0 General Location and Description..................................................................................5
2.1 Location .......................................................................................................................................................................................... 5
2.2 Description of Property ............................................................................................................................................................ 5
2.3 FLOODPLAIN ................................................................................................................................................................................. 8
3.0 Drainage Basins and Sub-Basins ....................................................................................8
3.1 Major Basin Description............................................................................................................................................................ 8
3.2 Sub-Basin Description ............................................................................................................................................................... 8
4.0 Drainage Design Criteria .................................................................................................9
4.1 Optional Revisions ...................................................................................................................................................................... 9
4.2 Development Criteria, Reference, and Constraints ....................................................................................................... 9
4.3 Hydrological Criteria .................................................................................................................................................................. 9
4.4 Hydraulic Criteria ......................................................................................................................................................................... 9
4.5 Floodplain Regulations Compliance ................................................................................................................................... 9
4.6 Modifications of Criteria ........................................................................................................................................................... 9
4.7 Storm Management Strategy .............................................................................................................................................. 10
5.0 Drainage Facility Design .............................................................................................. 10
5.1 General Concept....................................................................................................................................................................... 10
5.2 Specific Details .......................................................................................................................................................................... 11
6.0 Conclusions ................................................................................................................... 12
6.1 Compliance with Standards ................................................................................................................................................. 12
7.0 References ..................................................................................................................... 12
APPENDICES
APPENDIX A – Hydrologic Computations
APPENDIX B – Detention Pond Computations
APPENDIX C – Storm Sewers, Weirs, Inlets, and Swales
APPENDIX D – LID Design Information
APPENDIX E – Erosion Control Report
APPENDIX F – USDA Soils Report
MAP POCKET
DR1 – Historic Drainage Exhibit
DR2 – Drainage Exhibit
DR3 – Drainage Exhibit
WILLOX FARM
FIGURES AND TABLES
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TABLE OF FIGURES
Figure 1: Vicinity Map ................................................................................................................................................................ 5
Figure 2: Aerial Photograph .................................................................................................................................................... 6
Figure 3: Proposed Site Plan ................................................................................................................................................... 7
Figure 4: Regulatory Floodplains .......................................................................................................................................... 8
WILLOX FARM
ENGINEER CERTIFICATION
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1.0 ENGINEER CERTIFICATION
July 17, 2025
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
RE: FINAL DRAINAGE REPORT FOR
WILLOX FARM
Dear Staff:
EPS Group is pleased to submit this Final Drainage and Erosion Control Report for your review. This report accompanies
the combined Final Development Plan (FDP) submittal for the proposed Willox Farm.
This report has been prepared in accordance with the Fort Collins Stormwater Criteria Manual (FCSCM) and serves to
document the stormwater impacts associated with the proposed Willox Farm. We understand review by the City of Fort
Collins is to assure general compliance with standardized criteria contained in the FCSCM.
If you have any questions as you review this report, please feel free to contact us.
Sincerely,
EPS Group, Inc.
Jacob O'Banion, EI Ben Ruch, PE
Project Engineer Senior Project Engineer
WILLOX FARM
ENGINEER CERTIFICATION
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I hereby certify that this report for the final drainage design of Willox Farm was prepared by me or under my direct
supervision in accordance with the provisions of the City of Fort Collins Standards and Specifications and Construction of
Public and Private Improvements for the Responsible Parties thereof. I understand that the City of Fort Collins does not
and shall not assume liability for drainage facilities designed by others.
Benjamin R. Ruch
Registered Professional Engineer
State of Colorado No. 54317
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2.0 GENERAL LOCATION AND DESCRIPTION
2.1 LOCATION
1. Vicinity Map
2. The Willox Farm site is located in the Northwest ¼ of Section 2, Township 7 North, Range 69 West of the
6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado.
3. The project site (refer to Figure 1) is bordered to the north by W Willox Ln., to the south by Soft Gold Park,
to the east by Hickory Village and to the west by Garden Sweet and private property.
2.2 DESCRIPTION OF PROPERTY
1. The Willox Farm site is comprised of roughly ±19.01 acres.
2. The site currently exists as an undeveloped parcel with native ground cover. The existing ground slopes
with a mild grade (i.e., 0.4 – 0.6±%) through the interior to the southeast across flat grades. The drainage
continues through the South property boundary to Soft Gold Park.
Project
Location
Figure 1: Vicinity Map
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3. A subsurface exploration report was completed by Earth Engineering Consultants, LLC. on May 6, 2021
(EEC Project No. 1212027). At the time this report was written, the site was undeveloped with established
vegetation. According to Earth Engineering Consultants, the site consists of Clayey sand, silty, clayey sand
and/or sandy lean clay subsoils which were encountered beneath the surficial topsoil/vegetative layer
extended to depths of approximately 3 to 5 feet below existing site grades. Silty sand with gravel and
interbedded cobbles at increased depths, was encountered beneath the upper slightly cohesive zone
and extended to the bedrock formation. Siltstone/sandstone/claystone bedrock was encountered at
depths of approximately 16 to 18 feet below existing site grades.
4. According to the United States Department of Agriculture (USDA) Natural Resources Conservation
Service (NRCS) Soil Survey website: (http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx), the
site consists of Caruso Clay Loam (Hydrologic Soil Group D)and Table Mountain Loam (Hydrologic Soil
Group B). The calculations assume a Hydrologic Soil Group of D. Hydrologic Soil Group D has a very slow
rate of water absorption and infiltration
5. There are no major drainage ways on the site. However the Larimer - Weld Canal is located approximately
995’ north while the Cache La Poudre River is located approximately 2,220 feet south.
Figure 2: Aerial Photograph
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6. The proposed project site plan will consist of approximately 62 single Family residential lots. Other
proposed improvements include asphalt driveways, sidewalks and landscape areas. Figure 3 shows the
proposed site plan.
Figure 3: Proposed Site Plan
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2.3 FLOODPLAIN
The subject property is not located in a FEMA regulatory floodplain (see Figure 4).
3.0 DRAINAGE BASINS AND SUB-BASINS
3.1 MAJOR BASIN DESCRIPTION
1. Willox Farm is located in the Cache la Poudre River Basin, it is a major tributary to the South Platte River. It is
located in Larimer and Weld Counties, with a small portion of the drainage basin extending into southern
Wyoming. Passing through Fort Collins, the Poudre River corridor provides for stormwater drainage from
various contributing city drainage basins. Floodplain restrictions have limited the number of buildings in the
floodplain, resulting in lower development density. This lower density, combined with sensitivity to the
natural environment, has resulted in a high concentration of parks and open space along the river corridors.
3.2 SUB-BASIN DESCRIPTION
1. The subject property historically drains overland through the interior to the southeast across flat grades.
Runoff from the site has historically overflow to the southeast property boundary and then to Soft Gold
Park.
Figure 4: Regulatory Floodplains
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2. A more detailed description of the project drainage patterns is provided in sections below.
4.0 DRAINAGE DESIGN CRITERIA
4.1 OPTIONAL REVISIONS
1. There are no optional provisions outside of the Larimer County Stormwater Design Standards (LCSDS), City of
Fort Collins Standards and Specifications (FCSCM), and the Mile High Flood District (MHFD) Urban Storm
Drainage Criteria Manual (USDCM).
4.2 DEVELOPMENT CRITERIA, REFERENCE, AND CONSTRAINTS
1. In order to bring Willox Farm into compliance with current land use code and stormwater criteria, 75% of
all newly added impervious areas will be treated by LID techniques, in this case two rain gardens were
used and roughly 95.11% of all newly added impervious area is treated. The rain gardens will treat the
tributary area for water quality while meeting the City’s LID requirements. The detention pond will
provide the remaining necessary water quality treatment.
4.3 HYDROLOGICAL CRITERIA
1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the
FCSCM, serve as the source for all hydrologic computations associated with the proposed development.
Tabulated data contained in Table 3.4-1 was utilized for Rational Method runoff calculations.
2. The Rational Method was employed to compute localized stormwater runoff utilizing coefficients
contained in Tables 3.2-1 and 3.2-2 of the FCSCM.
3. Two separate design storms were utilized to address distinct drainage scenarios. The first event
analyzed is the "Minor" or "Initial" storm, which has a two-year recurrence interval. The second event
considered is the "Major" storm, which has a 100-year recurrence interval.
4. No other assumptions or calculation methods were used for this development that are not referenced
by the current City of Fort Collins criteria.
4.4 HYDRAULIC CRITERIA
1. As previously noted, the subject property maintains historical drainage patterns.
2. All drainage facilities proposed with the project are designed in accordance with the criteria outlined in the
FCSCM and/or Mile High Flood Control District’s Urban Storm Drainage Criteria Manual.
3. As discussed above, the subject property is not located in the 100-year floodplain. The proposed project
does not propose to modify any natural drainageways.
4.5 FLOODPLAIN REGULATIONS COMPLIANCE
1. As previously mentioned, this project is not subject to any floodplain regulations.
4.6 MODIFICATIONS OF CRITERIA
1. No formal modifications are requested at this time.
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4.7 STORM MANAGEMENT STRATEGY
1. The overall stormwater management strategy employed with Willox Farm utilizes the "Four Step Process" to
minimize adverse impacts of urbanization on receiving waters. The following describes how the proposed
development has incorporated each step.
a. Step 1 – Employ Runoff Reduction Practices. The first consideration taken in trying to reduce the
stormwater impacts of this development is the site selection itself and the selection of developable areas
on the site.
The Willox Farm aims to reduce runoff peaks, volumes, and pollutant loads from frequently occurring
storm events (i.e., water quality (i.e., 80th percentile) and two-year storm events). Site constraints limit the
possible Low Impact Development (LID) techniques; however, two rain gardens have been provided as
LID technique for storm quality management.
b. Step 2 – Implement Best Management Practices (BMPs) that provide a Water Quality Capture Volume
(WQCV) with slow release. The efforts taken in Step 1 will help to minimize excess runoff from frequently
occurring storm events; however, development still generates additional stormwater runoff beyond
historical conditions. The primary water quality treatment and volume control will occur in the detention
pond.
c. Step 3 – Stabilize Drainageways. There are no major drainageways within the subject property. While this
step may not seem applicable to proposed development, the project indirectly helps achieve stabilized
drainageways, nonetheless. By providing water quality treatment, where none previously existed,
sediment with erosion potential is removed from downstream drainageway systems.
d. Step 4 – Implement Site Specific and Other Source Control BMPs. This step typically applies to industrial
and commercial developments.
5.0 DRAINAGE FACILITY DESIGN
5.1 GENERAL CONCEPT
1. The main objectives of the project drainage design are to maintain existing drainage patterns and ensure
no adverse impacts on any adjacent properties.
2. The site receives offsite surface runoff from the Garden Sweet property to the northwest of the site. There
are also small amounts of offsite flows from W Willox Lane that will be captured and routed through the
site.
3. Onsite detention and water quality treatment for the Willox Farm project will be provided by the two rain
gardens, extended detention within the detention pond and the remainder within Detention Pond.
4. Irrigation flows owned by the City of Fort Collins will be passed through the pond and conveyed south to
the drainage swale on the west side of Soft Gold Park, until such time as the City’s Parks department
constructs a pipeline on the west side of the project site to convey these flows to the City owned irrigation
pond in Soft Gold Park.
5. LID treatment will be provided using two rain gardens on the southeast and southwest side of the project,
meeting the requirement that at least 75% of the new/improved impervious areas be treated. 94.16% of
the new/improved impervious areas will be treated with the proposed design.
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5.2 SPECIFIC DETAILS
1. The detention volume required for the Willox Farm site is 1.78 ac-ft. This volume was calculated using the
FAA Method.
2. City Code requires LIS treatment for all projects. This project proposed meeting the requirement using
two rain gardens as an LID technique. These rain gardens will capture majority of the water quality
volume (WQCV) for the full site. This configuration will treat 95.11% of the new impervious area.
3. The Willox Farm site has been broken into 12 onsite sub-basins and 7 offsite sub-basins for design
purposes. Anticipated drainage patterns for proposed drainage basins are described below:
Basin A1
Basin A1 consists of the back side of lots on the south portion of Saint Therese Street. This runoff
flows into proposed area inlets and then are routed south to Rain Garden A.
Basin A2
Basin A2 is comprised of the intersection of Moller Street and Saint Therese Street as well as the front
side of lots surrounding this intersection. Runoff travels via overland flow and curb and gutter to two
inlets on the west side of Moller Street. These proposed inlets and storm drain route flows south to
Rain Garden A.
Basin A3
Basin A3 is made up of open space and the back side of lots on the north portion of Saint Therese
Street. Flows travel via overland flow into a concrete channel that routes runoff to a storm drain and
eventually to Rain Garden A. Rain Garden A overtops into the detention pond which then controls
the release from the site.
Basin B1
Basin B1 consists of the backside of the lots lining Saint Grace Street. The basin blows directly south
into the Proposed Detention Pond. This basin will not be treated for LID in the rain gardens.
Basin B2
Basin B2 consists of Saint Grace Street and the south portions of Saint Jerome Street and Saint
Therese Street as well as the front side of the lots lining these streets. Flow from these basins travels
via overland flow and curb and gutter into Rain Garden B. Rain Garden B overtops into the Detention
Pond before being released from the site.
Basin B3
Basin B3 consists of portions of Saint Joseph Street as well as the back side of lots along Saint Therese
Street and Saint Jerome Street. Runoff travels via overland flow and curb and gutter before they are
routed into Basin B4 and eventually to Rain Garden B.
Basin B4
Basin B4 consists of back of lots and open space East of Saint Jerome Steet. Runoff travels via overland
flow into a concrete pan. These are routed to Rain Garden B.
Basin B5
Basin B5 consists of portions of Saint Joseph Street, Saint Therese Street, and Saint Jerome Street as
well as the front side of lots along these streets. Runoff travels via overland flow and curb and gutter
before they are routed into Basin B4 and eventually to Rain Garden B.
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Basin B6
Basin B6 consists of the back side of lots along Saint Joseph Street as well as open space. Flows in this
basin travel via overland flow into a concrete pan that routes flows into Basin B4. These flows
continue in the concrete channel to Rain Garden B.
Basin B7
Basin B7 is made up primarily of West Willox Lane and the north portion of Saint Therese Street. Flows
travel via overland flow and curb and gutter to a sidewalk culvert that routes into Basin B5 before
they continue into Basin B4 towards Rain Garden B.
Basin OS1 & OS2
Basin OS1 and Basin OS2 both consist primarily of open space. Basin OS1 flows generally to the
southeast and is captured in a swale on the west side of the site and routed through the Detention
Pond. If the property to the west develops in the future, their outfall would be able to connect to the
storm pipe that crosses Moller Street on the west side of the site. OS2 is routed through Basin A3 into
a proposed storm drain and then through the detention pond.
Basins OS3 & OS4
Basins OS3 and OS4 are comprised of portions of West Willox Lane and are collected by a proposed
storm pipe and routed along the west side of the site to an existing swale.
Basins OS5 & OS6
Basin OS5 is comprised of the east side of the site which is open space and will sheet flow east
mimicking historic flows. Basin OS6 is comprised of the southwest and southern part of the site which
is open space and will sheet flow southwest and south mimicking historic flows.
Basins OS7
Basin OS7 is comprised of the northeast side of the site which is open space with residential structure
and will sheet flow southeast to mimic historic flows.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report.
6.0 CONCLUSIONS
6.1 COMPLIANCE WITH STANDARDS
1. The proposed drainage design for the Willox Farm site complies with Larimer County Storm Drainage
Standards, the Urban Storm Drainage Criteria Manual Volumes 1, 2, and 3, and City of Fort Collins
Stormwater Criteria Manual.
2. There are no FEMA regulatory floodplains associated with the Willox Farm development.
3. The drainage design proposed with this project complies with the Cache la Poudre River Basin
requirements.
7.0 REFERENCES
City of Fort Collins Landscape Design Guidelines for Stormwater and Detention Facilities, November 5, 2009, BHA
Design, Inc. with City of Fort Collins Utility Services.
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Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, adopted by Ordinance No. 174, 2011, and
referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code.
Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1,
2002, Repealed and Reenacted, Effective April 1, 2007.
Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States
Department of Agriculture.
Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin
Engineers, Denver, Colorado, Revised April 2008.
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HISTORIC COMPOSITE RUNOFF COEFFICIENT CALCULATIONS
Project: 987-012
Calculations By: J. Obanion
Date: 7/17/2025
Character of Surface
Percent
Impervious1
2-year
Runoff
Coefficient
10-year Runoff
Coefficient
100-year Runoff
Coefficient
100% 0.95 0.95 1.00
90% 0.95 0.95 1.00
40% 0.50 0.50 0.625
45%
2% 0.20 0.20 0.25
Basin ID
Basin Area
(sq.ft.)
Basin Area
(acres)
Area of
Asphalt
(acres)
Area of
Driveways &
Sidewalks
(acres)
Area of
Gravel
(acres)
Area of
Residential
(acres)
Lawns and
Landscaping
(acres)
Percent
Impervious
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
h1 828,264 19.014 0.000 0.000 0.000 0.000 19.014 2%0.20 0.20 0.25
h2 169,963 3.902 0.000 0.000 0.000 0.000 3.902 2%0.20 0.20 0.25
h3 58,774 1.349 0.092 0.000 0.000 0.000 1.258 9%0.25 0.25 0.30
h4 23,803 0.546 0.221 0.000 0.000 0.000 0.325 42%0.50 0.50 0.55
Total 1,080,804 24.812 0.313 0.000 0.000 0.000 24.499 3%0.21 0.21 0.26
Asphalt......................................................................................................................................................................................
Driveway & Sidewalks...............................................................................................................................................................
Gravel.......................................................................................................................................................................................
Residential................................................................................................................................................................................
USDA SOIL TYPE: D
Unless noted, runoff coefficients are taken from Table 6-5 of the Urban Storm Drainage Criteria Manual (03/2017)
Lawns and Landscaping...........................................................................................................................................................
Page 1 of 3
Project:
Calculations By:
Date:
C5
Length,
L
(ft)
Slope, S
(%)
Ti
(min)
Length,
L
(ft)
Slope, S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope, S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Comp.
Tc
(min)
Actual
Tc
(min)
h1 h1 0.20 300 1.27 26.39 1166 1.20 2.19 8.87 N/A N/A N/A 35.26 18.14 18.14
h2 h2 0.20 300 0.50 36.01 300 0.50 1.41 3.54 N/A N/A N/A 39.54 13.33 13.33
h3 h3 0.25 300 1.79 22.24 N/A N/A N/A N/A N/A N/A 22.24 11.67 11.67
h4 h4 0.50 90 5.61 5.87 N/A N/A N/A 548 0.47 1.03 8.87 14.75 13.54 13.54
total Total 0.21 300 2.52 20.76 N/A N/A N/A 1320 0.41 0.96 22.91 43.67 19.00 19.00
Time of Concentration
Gutter/Swale Flow, Time of Concentration:
HISTORIC TIME OF CONCENTRATION COMPUTATIONS
Overland Flow Channelized Flow Swale Flow
Design
Point Basin(s)
Tt = L / 60V (Equation 6-4)
Tc = Ti + Tt (Equation 6-2)
Intensity, i From Figures 3.3.1-2 (Area II)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
Rational Equation: Q = CiA (Equation 6-1)
Overland Flow, Time of Concentration:
July 17, 2025
J. Obanion
987-012
(Equation 6-4)
(Equation 6-3)
}
31
51.1395.0
S
LCTi
10180L
Page 2 of 3
Overland Flow, Time of Concentration:
Gutter/Swale Flow, Time of Concentration:
Intensity, I from Fig. RA-2
Velocity (Gutter Flow), V = 20·S½Project:987-012
Velocity (Swale Flow), V = 15·S½Calculations By:J. Obanion
Rational Equation: Q = CiA (Equation 6-1)Date:
h1 h1 19.014 18.14 0.20 0.20 0.25 1.70 2.90 5.92 6.5 11.0 28.1
h2 h2 3.902 13.33 0.20 0.20 0.25 1.98 3.39 6.92 1.5 2.6 6.8
h3 h3 1.349 11.67 0.25 0.25 0.30 2.09 3.57 7.29 0.7 1.2 3.0
h4 h4 0.546 13.54 0.50 0.50 0.55 1.95 3.34 6.82 0.5 0.9 2.0
total Total 24.812 19 0.21 0.21 0.26 1.65 2.82 5.75 8.6 14.7 37.1
C2
Flow,
Q100
(cfs)
HISTORIC DIRECT RUNOFF COMPUTATIONS
C10 C100
Design
Point
Flow,
Q10
(cfs)
Flow,
Q2
(cfs)Basin(s)
Area, A
(acres)
Intensity,
I100
(in/hr)
July 17, 2025
Tc
(min)
Tt = L / 60V (Equation 6-4)
Tc = Ti + Tt (Equation 6-2)
Intensity, I2
(in/hr)
Intensity,
I10
(in/hr)
(Equation 6-4)
(Equation 6-3)
}
31
51.1395.0
S
LCTi
Page 3 of 3
Runoff Coefficient1
Percent
Impervious1 Project:
Location:
0.95 100%Calc. By:
0.95 90%Date:
0.50 40%
0.55 50%
0.20 2%
Basin ID Basin Area
(sq.ft.)
Basin Area
(acres)
Asphalt, Concrete
(acres)Rooftop (acres) Gravel (acres)Residential: Low
Density (acres)
Lawns, Clayey Soil,
Flat Slope < 2%
(acres)
Percent
Impervious
C2*Cf
Cf = 1.00
C5*Cf
Cf = 1.00
C10*Cf
Cf = 1.00
C100*Cf
Cf = 1.25
A1 33,711 0.77 0.00 0.00 0.00 0.53 0.24 35% 0.44 0.44 0.44 0.55
A2 56,029 1.29 0.52 0.00 0.00 0.53 0.23 62% 0.65 0.65 0.65 0.81
A3 104,532 2.40 0.07 0.00 0.00 0.53 1.80 15% 0.30 0.30 0.30 0.37
B1 30,861 0.71 0.00 0.00 0.00 0.71 0.00 50% 0.55 0.55 0.55 0.69
B2 122,579 2.81 0.76 0.00 0.00 1.61 0.44 56% 0.60 0.60 0.60 0.75
B3 50,754 1.17 0.02 0.00 0.00 0.65 0.50 30% 0.41 0.41 0.41 0.51
B4 75,858 1.74 0.34 0.00 0.00 0.75 0.65 42% 0.50 0.50 0.50 0.62
B5 159,140 3.65 1.31 0.00 0.00 1.77 0.57 60% 0.64 0.64 0.64 0.80
B6 37,612 0.86 0.08 0.00 0.00 0.20 0.58 22% 0.35 0.35 0.35 0.44
B7 24,334 0.56 0.39 0.00 0.00 0.00 0.17 71% 0.73 0.73 0.73 0.91
Total 695,409 15.96 3.50 0.00 0.00 7.28 5.18 45% 0.52 0.52 0.52 0.65
OS1 170,794 3.92 0.00 0.00 0.00 0.00 3.92 2% 0.20 0.20 0.20 0.25
OS2 23,162 0.53 0.24 0.00 0.00 0.00 0.29 46% 0.54 0.54 0.54 0.67
OS3 3,156 0.07 0.06 0.00 0.00 0.00 0.02 78% 0.78 0.78 0.78 0.97
OS4 7,250 0.17 0.08 0.00 0.00 0.00 0.08 51% 0.58 0.58 0.58 0.72
OS5 14,343 0.33 0.00 0.00 0.00 0.00 0.33 2% 0.20 0.20 0.20 0.25
OS6 8,307 0.19 0.01 0.00 0.00 0.00 0.18 6% 0.23 0.23 0.23 0.29
OS7 58,559 1.34 0.00 0.01 0.00 0.00 1.34 2% 0.20 0.20 0.20 0.25
Total 285,571 6.56 0.39 0.00 0.00 0.00 6.16 8%0.24 0.24 0.24 0.31
DEVELOPED RUNOFF COEFFICIENT CALCULATIONS
Asphalt, Concrete
Rooftop
Gravel
Streets, Parking Lots, Roofs, Alleys, and Drives:
Character of Surface:Willox
Fort Collins
J. Obanion
July 18, 2025
Lawns and Landscaping:
Offsite Basins
2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins
Stormwater Manual (FCSM).
Lawns, Clayey Soil, Flat Slope < 2%
USDA SOIL TYPE: C
Residential: Low Density Composite Runoff Coefficient2
1) Runoff coefficients per Tables 3.2-1 & 3.2 of the FCSM. Percent impervious per Tables 4.1-2 & 4.1-3 of the FCSM.
Onsite Basins
5/18/2022
Where:
Length
(ft)
Slope
(%)
Ti
2-Yr
(min)
Ti
10-Yr
(min)
Ti
100-Yr
(min)
Length
(ft)
Slope
(%)Surface n
Flow
Area3
(sq.ft.)
WP3 (ft)R (ft)V
(ft/s)
Tt
(min)
Max.
Tc
(min)
Comp.
Tc 2-Yr
(min)
Tc
2-Yr
(min)
Comp.
Tc 100-
Yr
(min)
Tc
100-Yr
(min)
a1 A1 115 3.07%9.09 9.09 7.56 513 0.50% Valley Pan 0.012 6.00 10.25 0.59 6.16 1.39 13.49 10.47 10.47 8.95 8.95
a2 A2 56 3.05%4.35 4.35 2.79 261 0.61% Gutter 0.012 3.61 19.18 0.19 3.17 1.37 11.76 5.72 5.72 4.16 5.00
a3 A3 94 8.27%7.19 7.19 6.52 308 0.54% Swale (4:1)0.035 4.00 8.25 0.48 1.93 2.66 12.23 9.85 9.85 9.18 9.18
b1 B1 67 6.25%4.57 4.57 3.43 N/A Gutter 0.012 3.61 19.18 N/A N/A 0.00 10.37 4.57 5.00 3.43 5.00
b2 B2 62 4.19%4.54 4.54 3.16 409 0.70%Gutter 0.012 3.61 19.18 0.19 3.41 2.00 12.62 6.54 6.54 5.16 5.16
b3 B3 86 1.83%9.83 9.83 8.39 370 0.50%Valley Pan 0.012 6.00 10.25 0.59 6.14 1.00 12.53 10.83 10.83 9.39 9.39
b4 B4 71 1.25%8.78 8.78 6.96 789 0.50%Valley Pan 0.012 6.00 10.25 0.59 6.12 2.15 14.78 10.93 10.93 9.11 9.11
b5 B5 85 2.28%6.04 6.04 3.95 700 0.50%Gutter 0.012 3.61 19.18 0.19 2.88 4.04 14.36 10.08 10.08 7.99 7.99
b6 B6 36 3.64%5.48 5.48 4.84 373 0.50%Valley Pan 0.012 6.00 10.25 0.59 6.15 1.01 12.27 6.49 6.49 5.85 5.85
b7 B7 25 1.80%2.86 2.86 1.47 230 0.12%Gutter 0.012 3.61 19.18 0.19 1.40 2.73 11.42 5.60 5.60 4.20 5.00
os1 OS1 200 1.00%23.80 23.80 23.80 350 0.42% Swale (8:1)0.035 8.00 16.12 0.50 1.73 3.37 13.06 27.17 13.06 27.17 13.06
os2 OS2 42 17.29%2.64 2.64 2.64 550 0.13% Swale (8:1)0.035 8.00 16.12 0.50 0.95 9.63 13.29 12.27 12.27 12.27 12.27
os3 OS3 23 2.39%2.15 2.15 2.15 22 0.91% Swale (8:1)0.035 8.00 16.12 0.50 2.54 0.14 10.25 2.29 5.00 2.29 5.00
os4 OS4 40 6.70%3.28 3.28 3.28 N/A Swale (8:1)0.035 8.00 16.12 N/A N/A 0.00 10.22 3.28 5.00 3.28 5.00
os5 OS5 40 3.73%6.87 6.87 6.87 N/A Swale (8:1)0.035 8.00 16.12 N/A N/A 0.00 10.22 6.87 6.87 6.87 6.87
os6 OS6 25 3.60%5.28 5.28 5.28 N/A Swale (8:1)0.035 8.00 16.12 N/A N/A 0.00 10.14 5.28 5.28 5.28 5.28
Offsite Basins
Notes
S = Longitudinal Slope, feet/feet
R = Hydraulic Radius (feet)
n = Roughness Coefficient
V = Velocity (ft/sec) WP = Wetted Perimeter (ft)
Design
Point Basin ID
Overland Flow Channelized Flow Time of Concentration
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Location:
Maximum Tc:Overland Flow, Time of Concentration:
Channelized Flow, Velocity: Channelized Flow, Time of Concentration:
Willox
Fort Collins
J. Obanion
July 18, 2025
Project:
Calculations By:
Date:
(Equation 3.3-2 per Fort Collins
Stormwater Manual)𝑇=1.87 1.1 − 𝐶 ∗ 𝐶𝑓𝐿
𝑆
𝑉 =1.49
𝑛∗ 𝑅/∗𝑆(Equation 5-4 per Fort Collins
Stormwater Manual)
𝑇𝑐 =𝐿
180 + 10 (Equation 3.3-5 per Fort Collins
Stormwater Manual)
𝑇𝑡 =𝐿
𝑉 ∗ 60
(Equation 5-5 per Fort Collins
1) Add 4900 to all elevations.
2) Per Fort Collins Stormwater Manual, minimum Tc = 5 min.
Tc2 Tc10 Tc100 C2 C10 C100 I2 I10 I100 WQ Q2 Q10 Q100
a1 A1 0.77 10.5 10.5 9.0 0.4 0.4 0.6 2.2 3.8 8.2 0.4 0.8 1.3 3.5
a2 A2 1.29 5.7 5.7 5.0 0.6 0.6 0.8 2.8 4.7 10.0 1.2 2.3 3.9 10.4
a3 A3 2.40 9.8 9.8 9.2 0.3 0.3 0.4 2.3 3.9 8.0 0.8 1.6 2.8 7.2
b1 B1 0.71 5.0 5.0 5.0 0.6 0.6 0.7 2.9 4.9 10.0 0.6 1.1 1.9 4.8
b2 B2 2.81 6.5 6.5 5.2 0.6 0.6 0.8 2.6 4.4 10.0 2.2 4.4 7.5 21.1
b3 B3 1.17 10.8 10.8 9.4 0.4 0.4 0.5 2.2 3.7 8.0 0.5 1.0 1.8 4.8
b4 B4 1.74 10.9 10.9 9.1 0.5 0.5 0.6 2.2 3.7 8.0 0.9 1.9 3.2 8.7
b5 B5 3.65 10.1 10.1 8.0 0.6 0.6 0.8 2.2 3.8 8.6 2.6 5.2 8.8 25.1
b6 B6 0.86 6.5 6.5 5.9 0.3 0.3 0.4 2.7 4.6 9.6 0.4 0.8 1.4 3.6
b7 B7 0.56 5.6 5.6 5.0 0.7 0.7 0.9 2.8 4.7 10.0 0.6 1.1 1.9 5.1
os1 OS1 3.92 13.1 13.1 13.1 0.2 0.2 0.2 2.0 3.4 6.9 0.8 1.6 2.7 5.4
os2 OS2 0.53 12.3 12.3 12.3 0.5 0.5 0.5 2.1 3.5 7.2 0.3 0.6 1.0 2.0
os3 OS3 0.07 5.0 5.0 5.0 0.8 0.8 0.8 2.9 4.9 10.0 0.1 0.2 0.3 0.6
os4 OS4 0.17 5.0 5.0 5.0 0.6 0.6 0.6 2.9 4.9 10.0 0.1 0.3 0.5 1.0
os5 OS5 0.33 6.9 6.9 6.9 0.2 0.2 0.2 2.6 4.4 9.1 0.1 0.2 0.3 0.6
os6 OS6 0.19 5.3 5.3 5.3 0.2 0.2 0.2 2.9 4.9 10.0 0.1 0.1 0.2 0.4
Offsite Basins
Fort Collins
Project:
Location:
Calc. By:
Intensity, I from Fig. 3.4.1 Fort Collins Stormwater Manual
Rational Equation: Q = CiA (Equation 6-1 per MHFD)
FLOW (CFS)
DEVELOPED DIRECT RUNOFF COMPUTATIONS
Intensity (in/hr)
Willox
J. Obanion
July 18, 2025
Design
Point Basin Area
(acres)
Runoff CTc (Min)
Date:
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
Pond No :
A
100-yr
0.65
13.50 min
15.96 acres Storage 77363 ft3
Max Release Rate =8.60 cfs 1.78 ac-ft
Time (min)
Ft Collins
100-yr
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
Qav
(cfs)
Outflow Volume
(ft3)
Storage
Volume
(ft3)
5 9.950 30966 1.00 8.60 2580 28386
10 7.720 48052 1.00 8.60 5160 42892
15 6.520 60875 1.00 8.60 7740 53135
20 5.600 69713 1.00 8.60 10320 59393
25 4.980 77494 1.00 8.60 12900 64594
30 4.520 84403 1.00 8.60 15480 68923
35 4.080 88884 1.00 8.60 18060 70824
40 3.740 93117 1.00 8.60 20640 72477
45 3.460 96914 1.00 8.60 23220 73694
50 3.230 100524 1.00 8.60 25800 74724
55 3.030 103730 1.00 8.60 28380 75350
60 2.860 106811 1.00 8.60 30960 75851
65 2.720 110047 1.00 8.60 33540 76507
70 2.590 112848 1.00 8.60 36120 76728
75 2.480 115774 1.00 8.60 38700 77074
80 2.380 118513 1.00 8.60 41280 77233
85 2.290 121158 1.00 8.60 43860 77298
90 2.210 123803 1.00 8.60 46440 77363
95 2.130 125951 1.00 8.60 49020 76931
100 2.060 128223 1.00 8.60 51600 76623
105 2.000 130712 1.00 8.60 54180 76532
110 1.940 132829 1.00 8.60 56760 76069
115 1.890 135287 1.00 8.60 59340 75947
120 1.840 137435 1.00 8.60 61920 75515
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Input Variables Results
Required Detention Volume
Fort Collins, Colorado
987-012
Willox Farm
Project Number :
Project Name :
Detention Pond
A =
Tc =
Project Location :
Design Point
C =
Design Storm
Page 1 of 1
987-012_Pond_FAA_Fort Collins_Pond A
Pond Stage-Storage Curve
Detention Pond
987-012 Willox Farm
By: J. Obanion
Date: 04/09/2024
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
4,983.00 28.22 0.00 0.00
4,983.20 484.26 51.25 0.00
4,983.40 2,121.90 311.86 0.01
4,983.60 4,302.37 954.29 0.02
4,983.80 6,643.77 2048.90 0.05
4,984.00 9,455.39 3658.82 0.08
4,984.20 12,798.94 5884.25 0.14
4,984.40 16,695.20 8833.67 0.20
4,984.60 21,130.71 12616.26 0.29
4,984.80 31,797.69 17338.86 0.40
4,985.00 37,419.61 23120.11 0.53
4,985.20 44,734.51 31176.17 0.72
4,985.40 49,509.05 40600.52 0.93
4,985.60 53,584.85 50909.91 1.17
4,985.80 57,615.44 62029.94 1.42
4,986.00 61,941.89 73182.66 1.68
4,986.07 63,262.55 77363.00 1.78 100-YR DETENTION
4,986.20 65,893.69 85691.41 1.97
Willox Farm
ORIFICE RATING CURVE
Detention Pond
100-yr Orifice
Project:Willox Farm
Date:7/17/2025
By:J. Obanion
100-yr WSEL=4986.07
Orifice Plate
Outflow Q 8.6 cfs
Orifice Coefficient Cd 0.65
Gravity Constant g 32.2 ft/s^2
100-year head H 3.09 ft
Orifice Area Ao 0.94 ft^2
Orifice Area Ao 135.06 in^2
Radius r 6.0 in
Diameter d 12.0 in
Orifice Curve
Stage (ft)H (ft)Q (cfs)Stage (ft)Note
4983.00 0.02 0.69 0.00 Pond Invert
4983.20 0.22 2.29 0.20
4983.40 0.42 3.17 0.40
4983.60 0.62 3.85 0.60
4983.80 0.82 4.43 0.80
4984.00 1.02 4.94 1.00
4984.20 1.22 5.40 1.20
4984.40 1.42 5.83 1.40
4984.60 1.62 6.23 1.60
4984.80 1.82 6.60 1.80
4985.00 2.02 6.95 2.00
4985.20 2.22 7.29 2.20
4985.40 2.42 7.61 2.40
4985.60 2.62 7.92 2.60
4985.80 2.82 8.22 2.80
4986.00 3.02 8.50 3.00
4986.07 3.09 8.60 3.07 100-Yr WSEL
7/17/2025 10:45 AM P:\987-012\Drainage\Detention\987-012_Circular Orifice Rating\Orifice Size
Weir Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jul 18 2025
Pond Emergency Spillway
Trapezoidal Weir
Crest = Sharp
Bottom Length (ft) = 75.00
Total Depth (ft) = 1.00
Side Slope (z:1) = 4.00
Calculations
Weir Coeff. Cw = 3.10
Compute by: Known Q
Known Q (cfs) = 94.30
Highlighted
Depth (ft) = 0.54
Q (cfs) = 94.30
Area (sqft) = 41.67
Velocity (ft/s) = 2.26
Top Width (ft) = 79.32
0 10 20 30 40 50 60 70 80 90 100 110
Depth (ft) Depth (ft)Pond Emergency Spillway
-0.50 -0.50
0.00 0.00
0.50 0.50
1.00 1.00
1.50 1.50
2.00 2.00
Length (ft)Weir W.S.
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
Structure ID WQ Model HGL (ft) Flow Depth Above Weir (ft) Upstream Storm Sewer Model HGL (ft) Downstream Storm Sewer Model HGL (ft) Controlling HGL (ft)
STMH A2 w Weir 4986.65 1.43 4988.08 4986.84 4988.08
1. HGL at STMH A2 - WQ Storm Event (Sets the Weir Height in STMH A2 to 4986.65)
2. From Hydraflow Express Weir Model using 100-Yr Storm Event
3. Weir Height Plus Flow Depth Above Weir (Used as starting HGL for Upstream Storm Sewer Model)
4. HGL Produced in STMH A2 from 100-YR Storm Event Storm Sewer Model (For Comparison to Upstream HGL)
5. The highest HGL in STMH A2 of all Storm A Storm Sewer Models
Water Quality Weir Modeling Summary
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
Project:987-012
Calculations By:Jacob Obanion
Date:
Design
Point
Design Inlet
Label Q2 Q100 Q100 Total Q100
Intercepted
Q100
Unintercepted Inlet Type Inlet Size Notes
A1 INLET A4-1 0.38 1.75 1.75 1.75 0.00 Nyloplast Basin Dome Grate 12"-
A1 INLET A5-1 0.38 1.75 1.75 1.75 0.00 Nyloplast Basin Dome Grate 12"-
A2 INLET A6 1.15 5.19 5.19 5.19 0.00 Type 13 Combo Single -
A2 INLET A7 1.15 5.19 5.19 5.19 0.00 Type 13 Combo Single -
INLET CAPACITY SUMMARY
July 17, 2025
P:\987-012\Drainage\Inlets\Inlet Summary Table\Inlet summary
Project:
Inlet ID:
Gutter Geometry:
Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ftSide Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ftManning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.012
Height of Curb at Gutter Flow Line HCURB =4.74 inchesDistance from Curb Face to Street Crown TCROWN =15.0 ft
Gutter Width W =2.58 ftStreet Transverse Slope SX =0.002 ft/ftGutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft
Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ftManning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012
Minor Storm Major Storm
Max. Allowable Spread for Minor & Major Storm TMAX =15.0 15.0 ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =4.7 12.0 inches
Check boxes are not applicable in SUMP conditions
MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm
MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallow =SUMP SUMP cfs
MHFD-Inlet, Version 5.03 (August 2023)ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)Willox Farm
Inlet A6
987-012_MHFD-Inlet_v5.03, Inlet A6 7/17/2025, 10:49 AM
Design Information (Input)MINOR MAJORType of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches
Number of Unit Inlets (Grate or Curb Opening)No =1 1 Water Depth at Flowline (outside of local depression)Ponding Depth =4.7 12.0 inches
Grate Information MINOR MAJORLength of a Unit Grate Lo (G) =3.00 3.00 feet
Width of a Unit Grate Wo =1.73 1.73 feet
Open Area Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50
Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30
Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60Curb Opening Information MINOR MAJORLength of a Unit Curb Opening Lo (C) =3.00 3.00 feet
Warning 1 Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches
Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches
Angle of Throat Theta =0.00 0.00 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.58 2.58 feet
Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66
Low Head Performance Reduction (Calculated)MINOR MAJORDepth for Grate Midwidth dGrate =0.43 1.04 ft
Depth for Curb Opening Weir Equation dCurb =0.18 0.79 ftGrated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.73 1.00
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =N/A N/A
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.73 1.00
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =2.3 9.6 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q Peak)Q PEAK REQUIRED =1.2 5.2 cfs
Warning 1: Dimension entered is not a typical dimension for inlet type specified.
CDOT/Denver 13 Combination
INLET IN A SUMP OR SAG LOCATIONMHFD-Inlet, Version 5.03 (August 2023)
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT/Denver 13 Combination
Override
987-012_MHFD-Inlet_v5.03, Inlet A6 7/17/2025, 10:49 AM
Project:
Inlet ID:
Gutter Geometry:
Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ftSide Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ftManning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.012
Height of Curb at Gutter Flow Line HCURB =4.74 inchesDistance from Curb Face to Street Crown TCROWN =15.0 ft
Gutter Width W =2.58 ftStreet Transverse Slope SX =0.000 ft/ftGutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft
Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ftManning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012
Minor Storm Major Storm
Max. Allowable Spread for Minor & Major Storm TMAX =15.0 15.0 ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =4.7 12.0 inches
Check boxes are not applicable in SUMP conditions
MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm
MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallow =SUMP SUMP cfs
MHFD-Inlet, Version 5.03 (August 2023)ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)Willox Farm
Inlet A7
987-012_MHFD-Inlet_v5.03, Inlet A7 7/17/2025, 10:49 AM
Design Information (Input)MINOR MAJORType of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches
Number of Unit Inlets (Grate or Curb Opening)No =1 1 Water Depth at Flowline (outside of local depression)Ponding Depth =4.7 12.0 inches
Grate Information MINOR MAJORLength of a Unit Grate Lo (G) =3.00 3.00 feet
Width of a Unit Grate Wo =1.73 1.73 feet
Open Area Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50
Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30
Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60Curb Opening Information MINOR MAJORLength of a Unit Curb Opening Lo (C) =3.00 3.00 feet
Warning 1 Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches
Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches
Angle of Throat Theta =0.00 0.00 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.58 2.58 feet
Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66
Low Head Performance Reduction (Calculated)MINOR MAJORDepth for Grate Midwidth dGrate =0.43 1.04 ft
Depth for Curb Opening Weir Equation dCurb =0.18 0.79 ftGrated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.73 1.00
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =N/A N/A
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.73 1.00
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =2.3 9.6 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q Peak)Q PEAK REQUIRED =1.2 5.2 cfs
Warning 1: Dimension entered is not a typical dimension for inlet type specified.
CDOT/Denver 13 Combination
INLET IN A SUMP OR SAG LOCATIONMHFD-Inlet, Version 5.03 (August 2023)
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT/Denver 13 Combination
Override
987-012_MHFD-Inlet_v5.03, Inlet A7 7/17/2025, 10:49 AM
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jul 18 2025
A1 - A1
User-defined
Invert Elev (ft) = 89.57
Slope (%) = 0.50
N-Value = 0.034
Calculations
Compute by: Known Q
Known Q (cfs) = 11.54
(Sta, El, n)-(Sta, El, n)...
( 0.00, 90.30)-(11.08, 89.65, 0.035)-(12.08, 89.57, 0.012)-(13.08, 89.65, 0.012)-(23.07, 90.14, 0.035)-(40.97, 90.30, 0.035)
Highlighted
Depth (ft) = 0.71
Q (cfs) = 11.54
Area (sqft) = 9.67
Velocity (ft/s) = 1.19
Wetted Perim (ft) = 38.43
Crit Depth, Yc (ft) = 0.50
Top Width (ft) = 38.39
EGL (ft) = 0.73
-5 0 5 10 15 20 25 30 35 40 45 50
Elev (ft) Depth (ft)Section
89.00 -0.57
89.50 -0.07
90.00 0.43
90.50 0.93
91.00 1.43
Sta (ft)
Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jul 18 2025
A2 - A2
User-defined
Invert Elev (ft) = 85.15
Slope (%) = 0.50
N-Value = 0.033
Calculations
Compute by: Known Q
Known Q (cfs) = 62.78
(Sta, El, n)-(Sta, El, n)...
( 0.00, 87.05)-(6.96, 85.65, 0.035)-(7.46, 85.15, 0.012)-(11.49, 85.15, 0.012)-(12.06, 85.65, 0.012)-(19.54, 86.03, 0.035)-(32.71, 86.30, 0.035)
-(52.89, 87.05, 0.035)
Highlighted
Depth (ft) = 1.57
Q (cfs) = 62.78
Area (sqft) = 26.95
Velocity (ft/s) = 2.33
Wetted Perim (ft) = 42.98
Crit Depth, Yc (ft) = 1.29
Top Width (ft) = 42.46
EGL (ft) = 1.65
-5 0 5 10 15 20 25 30 35 40 45 50 55 60
Elev (ft) Depth (ft)Section
84.50 -0.65
85.00 -0.15
85.50 0.35
86.00 0.85
86.50 1.35
87.00 1.85
87.50 2.35
88.00 2.85
Sta (ft)
Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jul 18 2025
A3 - A3
User-defined
Invert Elev (ft) = 87.01
Slope (%) = 0.50
N-Value = 0.034
Calculations
Compute by: Known Q
Known Q (cfs) = 19.50
(Sta, El, n)-(Sta, El, n)...
( 0.00, 87.96)-(1.83, 87.74, 0.035)-(116.62, 87.51, 0.035)-(117.12, 87.01, 0.012)-(121.12, 87.01, 0.012)-(121.62, 87.51, 0.012)-(124.90, 87.96, 0.035)
Highlighted
Depth (ft) = 0.77
Q (cfs) = 19.50
Area (sqft) = 21.66
Velocity (ft/s) = 0.90
Wetted Perim (ft) = 122.53
Crit Depth, Yc (ft) = 0.67
Top Width (ft) = 122.09
EGL (ft) = 0.78
-10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Elev (ft) Depth (ft)Section
86.75 -0.26
87.00 -0.01
87.25 0.24
87.50 0.49
87.75 0.74
88.00 0.99
Sta (ft)
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =32.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.320
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.13 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 194,271 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =2,041 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =1243 sq ft
D) Actual Flat Surface Area AActual =1406 sq ft
E) Area at Design Depth (Top Surface Area)ATop =2885 sq ft
F) Rain Garden Total Volume VT=2,145 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =50.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =2,041 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =9/16 in
Design Procedure Form: Rain Garden (RG)
J. Obanion
Northern Engineering
July 17, 2025
Willox - Rain Garden A
Fort Collins, CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_RAIN GARDEN_A, RG 7/17/2025, 11:08 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
J. Obanion
Northern Engineering
July 17, 2025
Willox - Rain Garden A
Fort Collins, CO
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose OneYES
NO
YES
NO
UD-BMP_v3.07_RAIN GARDEN_A, RG 7/17/2025, 11:08 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =51.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.510
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.17 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 470,276 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =6,552 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =4797 sq ft
D) Actual Flat Surface Area AActual =5207 sq ft
E) Area at Design Depth (Top Surface Area)ATop =8030 sq ft
F) Rain Garden Total Volume VT=6,619 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =50.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =6,552 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =15/16 in
Design Procedure Form: Rain Garden (RG)
J. Obanion
Northern Engineering
July 17, 2025
Willox - Rain Garden A
Fort Collins, CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_RAIN GARDEN_B, RG 7/17/2025, 11:08 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
J. Obanion
Northern Engineering
July 17, 2025
Willox - Rain Garden A
Fort Collins, CO
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose OneYES
NO
YES
NO
UD-BMP_v3.07_RAIN GARDEN_B, RG 7/17/2025, 11:08 AM
Project Number:Project:Willox Farm
Project Location:
Calculations By:Date:7/17/2025
Sq. Ft. Acres
A1 33,711 0.77 35%Rain Garden A Rain Garden 11,841
A2 56,029 1.29 62%Rain Garden A Rain Garden 34,513
A3 104,532 2.40 15% Rain Garden A Rain Garden 16,072
B1 30,861 0.71 50% n/a n/a 15,430
B2 122,579 2.81 56% Rain Garden B Rain Garden 68,576
B3 50,754 1.17 30% Rain Garden B Rain Garden 15,396
B4 75,858 1.74 42% Rain Garden B Rain Garden 31,888
B5 159,140 3.65 60% Rain Garden B Rain Garden 96,188
B6 37,612 0.86 22% Rain Garden B Rain Garden 8,281
B7 24,334 0.56 71% Rain Garden B Rain Garden 17,259
OS1 170,794 3.92 2% n/a n/a 3,416
OS2 23,162 0.53 46% n/a n/a 10,668
OS3 3,156 0.07 78% n/a n/a 2,453
OS4 7,250 0.17 51% n/a n/a 3,718
OS5 14,343 0.33 2% n/a n/a 287
OS6 8,307 0.19 6% n/a n/a 539
OS7 58,559 1.34 2% n/a n/a 1,435
Total 980,980 22.52 337,960
Project Number: Project:
Project Location:
Calculations By: Date:
Sq. Ft. Acres
Rain Garden A 194,271 4.46 32%A1,A2,A3 Rain Garden 3,588 62,426
Rain Garden B 470,276 10.80 51%
B2,B3,B4,B5,B6,
B7 Rain Garden 6,875 237,588
Total 664,548 15.26 300,014
Total Area of Current Development 695,409 ft2
Total Impervious Area 315,444 ft2
Total Impervious Area without LID Treatment 15,430 ft2
B1
75% Requried Minimum Area to be Treated 236,583 ft2
Total Treated Area 300,014 ft2
Percent Impervious Treated by LID 95.11%
LID Site Summary - New Impervious Area
LID Summary per LID Structure
LID Summary
Willox Farm
7/17/2025
Weighted %
Impervious
Impervious
Area (ft2)
Volume per
UD-BMP (ft3)LID ID Area
987-012
Fort Collins, Colorado
J. Obanion
Subbasin ID Treatment Type
LID Summary
AreaBasin ID Treatment TypePercent
Impervious LID ID
987-012
Fort Collins, Colorado
J. Obanion
Total
Impervious
Area (ft2)
LID Summary per Basin
UD
IR
E
E
E
E
E
E
E
E E
E
E
E
E
E
E
E
E
T
S
S
T
T
T
T
E
E
E
W W W W W W W W
W
W
W
W
SOFT GOLD PARK
DETENTION POND
WILLOX LN
RAIN GARDEN A
REQUIRED VOLUME: 2,041 CU. FT.
MINIMUM FLAT AREA: 1,243 SF
PROVIDED VOLUME: 2,145 CU. FT.
PROVIDED FLAT AREA: 1,406 SF
IMPERVIOUS AREA TREATED: 62,426 SF
RAIN GARDEN B
REQUIRED VOLUME: 6,552 CU. FT.
MINIMUM FLAT AREA: 4,797 SF
PROVIDED VOLUME: 6,619 CU. FT.
PROVIDED FLAT AREA: 5,207 SF
IMPERVIOUS AREA TREATED: 237,558 SF
0.07 ac.
OS3
1.17 ac.
B3
0.71 ac.
B1
1.74 ac.
B4
0.86 ac.
B6
3.90 ac.
OS1
0.56 ac.
B7
2.40 ac.
A3
0.55 ac.
OS2
0.77 ac.
A1
0.19 ac.
OS6
2.32 ac.
A
1.34 ac.
OS7
0.17 ac.
OS4
0.32 ac.
OS5
2.81 ac.
B2
1.29 ac.
A2
3.65 ac.
B5
WILLOX FARM
SHEET NO:
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301 N. Howes Street, Suite 100
Fort Collins, Colorado 80521
PHONE: 970.221.4158
www.epsgroupinc.com
DRAWING REFERENCE:
LID TREATMENT EXHIBIT J. OBANION
1"=150'
APRIL 2025 LID-1
DRAWN BY:
SCALE:
ISSUED:
NOTES
1.FOR LID RAIN GARDEN CALCULATIONS PLEASE REFER TO THE
FINAL DRAINAGE REPORT DATED APRIL 25, 2025.
2.REFER TO UTILITY PLANS FOR WILLOX FARM FOR ADDITIONAL
GRADING AND UTILITY INFORMATION.
3.REFER TO LANDSCAPE PLANS FOR ADDITIONAL INFORMATION ON
HARDSCAPES.
LEGEND
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
AREA TREATED BY RAIN GARDEN B
AREA TREATED BY RAIN GARDEN A
NORTH
( IN FEET )
0
1 INCH = 150 FEET
150 150
LID Site Summary - New Impervious Area
Total Area of Current Development 695,409 ft2
Total Impervious Area 315,444 ft2
Total Impervious Area without LID Treatment: Basin A1 15,430 ft2
75% Requried Minimum Area to be Treated 236,583 ft2
Total Treated Area 300,014 ft2
Percent Impervious Treated by LID 95.11%ft2
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
WILLOX FARM
APPENDIX
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) has been included with the final
construction drawings. It should be noted; however, any such Erosion and Sediment Control Plan serves only as a general
guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those
included may be necessary during construction, or as required by the authorities having jurisdiction.
It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed.
The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and
needs. The Contractor shall update the location of BMPs as they are installed, removed, or modified in conjunction with
construction activities. It is imperative to appropriately reflect the current site conditions at all times.
The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction,
as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 – Construction
BMPs will be utilized. Measures may include, but are not limited to, silt fencing and/or wattles along the disturbed
perimeter, gutter protection in the adjacent roadways, and inlet protection at existing and proposed storm inlets. Vehicle
tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job
site restrooms shall also be provided by the Contractor.
Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The Final Utility Plans will also contain a
full-size Erosion Control Plan as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and
the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable requirements outlined in any
existing Development Agreement(s) of record, as well as the Development Agreement, to be recorded prior to issuance of
the Development Construction Permit. Also, the Site Contractor for this project may be required to secure a Stormwater
Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality
Control Division – Stormwater Program, before commencing any earth disturbing activities. Prior to securing said permit,
the Site Contractor shall develop a comprehensive Storm Water Management Plan (SWMP) pursuant to CDPHE
requirements and guidelines. The SWMP will further describe and document the ongoing activities, inspections, and
maintenance of construction BMPs.
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
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
Larimer County
Area, ColoradoNatural
Resources
Conservation
Service
March 9, 2022
9
Custom Soil Resource Report
Soil Map
44
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492450 492500 492550 492600 492650 492700 492750
492450 492500 492550 492600 492650 492700 492750
40° 36' 39'' N
10
5
°
5
'
2
1
'
'
W
40° 36' 39'' N
10
5
°
5
'
7
'
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W
40° 36' 24'' N
10
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°
5
'
2
1
'
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W
40° 36' 24'' N
10
5
°
5
'
7
'
'
W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600Feet
0 30 60 120 180Meters
Map Scale: 1:2,200 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 16, 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: Aug 11, 2018—Aug
12, 2018
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
22 Caruso clay loam, 0 to 1
percent slope
14.2 78.9%
105 Table Mountain loam, 0 to 1
percent slopes
3.8 21.1%
Totals for Area of Interest 17.9 100.0%
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
11
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
12
Larimer County Area, Colorado
22—Caruso clay loam, 0 to 1 percent slope
Map Unit Setting
National map unit symbol: jpvt
Elevation: 4,800 to 5,500 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Caruso and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Caruso
Setting
Landform:Flood-plain steps, stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium
Typical profile
H1 - 0 to 35 inches: clay loam
H2 - 35 to 44 inches: fine sandy loam
H3 - 44 to 60 inches: gravelly sand
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat poorly drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table:About 24 to 48 inches
Frequency of flooding:NoneOccasional
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 8.4 inches)
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonirrigated): 5w
Hydrologic Soil Group: D
Ecological site: R067BY036CO - Overflow
Hydric soil rating: No
Minor Components
Loveland
Percent of map unit:9 percent
Custom Soil Resource Report
13
Landform:Terraces
Ecological site:R067BY036CO - Overflow
Hydric soil rating: Yes
Fluvaquents
Percent of map unit:6 percent
Landform:Terraces
Hydric soil rating: Yes
105—Table Mountain loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpty
Elevation: 4,800 to 5,600 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Table mountain and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Table Mountain
Setting
Landform:Stream terraces, flood plains
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 36 inches: loam
H2 - 36 to 60 inches: clay loam
Properties and qualities
Slope:0 to 1 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 2.00 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)
Sodium adsorption ratio, maximum:5.0
Available water supply, 0 to 60 inches: High (about 9.8 inches)
Custom Soil Resource Report
14
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Ecological site: R049XY036CO - Overflow
Hydric soil rating: No
Minor Components
Caruso
Percent of map unit:7 percent
Hydric soil rating: No
Fluvaquentic haplustolls
Percent of map unit:4 percent
Landform:Terraces
Hydric soil rating: Yes
Paoli
Percent of map unit:4 percent
Hydric soil rating: No
Custom Soil Resource Report
15
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
16
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
17
Fort Collins | Greeley | (970) 221-4158 | epsgroupinc.com
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h1
WEST WILLOW LANE
EXISTING 20' SANITARY SEWER EASEMENT TO BE VACATED WITH PLAT (ENCROACHES ON PROPERTY. SEE PLAT FOR NOTES)
EXISTING 10' UTILITY EASEMENT
EXISTING 6' CITY OF
FORT COLLINS EASEMENT
EXISTING 10'
MOUNTAIN STATES UTILITY
EASEMENT
EXISTING 30'
NCWA EASEMENT
EXISTING 6' CITY OF
FORT COLLINS EASEMENT 100' UNION PACIFIC
RAILROAD ROW
PROPERTY
BOUNDARY
PROPERTY
BOUNDARY
PROPERTY
BOUNDARY
PROPERTY
BOUNDARY
EXISTING 20' PUBLIC
DRAINAGE EASEMENT
ACKELSON CONNIE A. 603
W WILLOX LANE,
KAFKA, AMY
709 W WILLOX LANE,
PITT, JEAN
1522 WOOD LANE,
GBP LLC
1434 WOOD LANE,
PEREZ DANIEL A.
400 HICKORY STREET 149
PEREZ DANIEL A.
400 HICKORY STREET 149
3.90 ac.
h2
1.35 ac.
h3
0.55 ac.
h4
KEYMAP
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HICKORY STREET
SOFT
GOLD PARK
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NORTH
( IN FEET )
0
1 INCH = 60 FEET
60 60 120 180
DR1
HI
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58
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION 11
NOTES:
A
LEGEND:
1.REFER TO THE FINAL DRAINAGE REPORT DATED APRIL 25, 2025 BY EPS GROUP FOR
ADDITIONAL INFORMATION.
DR1
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
before you dig.Call
RHistoric Drainage Summary
Design
Point Basin(s)Area, A
(acres)
Tc
(min)C2 C10 C100 Intensity, I2
(in/hr)
Intensity,
I10
(in/hr)
Intensity,
I100
(in/hr)
Flow,
Q2
(cfs)
Flow,
Q10
(cfs)
Flow,
Q100
(cfs)
h1 h1 19.01 18.14 0.20 0.20 0.25 1.70 2.90 5.92 6.46 11.03 28.14
h2 h2 3.90 13.33 0.20 0.20 0.25 1.98 3.39 6.92 1.55 2.65 6.75
h3 h3 1.35 11.67 0.25 0.25 0.30 2.09 3.57 7.29 0.70 1.20 2.95
h4 h4 0.55 13.54 0.50 0.50 0.55 1.95 3.34 6.82 0.53 0.91 2.05
total Total 24.81 19.00 0.21 0.21 0.26 1.65 2.82 5.75 8.60 14.69 37.09
/ / / / / / / // / / / / / / /
/ / / / / / / /
W WWW
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SAINT JOSEPH STREET
WILLOX LN
ACKELSON CONNIE A.
KAFKA, AMY
PROPERTY
BOUNDARY
PROPERTY
BOUNDARY
PROPERTY
BOUNDARY
SA
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PROPOSED 2-2'
SIDEWALK CHASES
PROPOSED 4'
SIDEWALK CULVERT
PROPOSED 4'
CONCRETE
PAN w/ CURB
PROPOSED 2'
SIDEWALK CHASE
PROPOSED 2'
CONCRETE PAN
PROPOSED 4'
SIDEWALK CULVERT
PROPOSED 2'
CONCRETE PAN
WILLOX STORM DRAIN
SEE SHEET ST3
WILLOX EAST STORM DRAIN
SEE SHEET ST4
1.17 ac.
B3
1.74 ac.
B4
0.86 ac.
B6
0.07 ac.
OS3
3.90 ac.
OS1
0.56 ac.
B7
2.40 ac.
A3
0.55 ac.
OS2
1.34 ac.
OS7
0.17 ac.
OS4
0.32 ac.
OS5
3.65 ac.
B5
PROPOSED
FOREBAY
KEYMAP
T
WEST WILLOX LANE
HICKORY STREET
SOFT
GOLD PARK
Sheet
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59
NORTH
( IN FEET )
1 inch = ft.
Feet04040
40
80 120
1.REFER TO THE "FINAL DRAINAGE REPORT DATED APRIL 25, 2025" BY EPS GROUP
FOR ADDITIONAL INFORMATION.
2.THE WILLOX FARM PROJECT WILL BE DETAINING THE DIFFERENCE BETWEEN THE
HISTORIC 2-YEAR EVENT AND THE DEVELOPED 100-YEAR EVENT.
3.LID MEASURES IS PROVIDED VIA RAIN GARDEN.
4.ALL PROPOSED STORM SEWER ARE TO BE PRIVATELY OWNED AND MAINTAINED.
SWALE SECTIONS
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION 11
NOTES:
A
LEGEND:
MATCH LINE - SEE SHEET DR3
DR2
DR3
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
before you dig.Call
R
DEVELOPED DRAINAGE SUMMARY
Design
Point Basin ID
Total
Area
(acres)
C2 C100 2-Yr Tc
(min)
100-Yr
Tc (min)WQ Q2
(cfs)
Q100
(cfs)
a1 A1 0.77 0.44 0.55 10.47 10.47 0.38 0.76 3.50
a2 A2 1.29 0.65 0.81 5.72 5.72 1.15 2.30 10.38
a3 A3 2.40 0.30 0.37 9.85 9.85 0.81 1.62 7.19
b1 B1 0.71 0.55 0.69 5.00 5.00 0.56 1.11 4.85
b2 B2 2.81 0.60 0.75 6.54 6.54 2.20 4.40 21.10
b3 B3 1.17 0.41 0.51 10.83 10.83 0.51 1.03 4.76
b4 B4 1.74 0.50 0.62 10.93 10.93 0.94 1.89 8.72
b5 B5 3.65 0.64 0.80 10.08 10.08 2.58 5.16 25.06
b6 B6 0.86 0.35 0.44 6.49 6.49 0.40 0.80 3.63
b7 B7 0.56 0.73 0.91 5.60 5.60 0.56 1.12 5.05
Offsite Basins
os1 OS1 3.92 0.20 0.20 13.06 13.06 0.78 1.55 5.43
os2 OS2 0.53 0.54 0.54 12.27 12.27 0.29 0.59 2.05
os3 OS3 0.07 0.78 0.78 5.00 5.00 0.08 0.16 0.56
os4 OS4 0.17 0.58 0.58 5.00 5.00 0.14 0.27 0.96
os5 OS5 0.33 0.20 0.20 6.87 6.87 0.09 0.17 0.60
os6 OS6 0.19 0.23 0.23 5.28 5.28 0.06 0.13 0.44
os7 OS7 1.34 0.20 0.20 11.39 11.39 0.29 0.58 2.03
POND SUMMARY TABLE
Pond ID Tributary
Area (ac)
Avg. Percent
Imperviousness
(%)
100-Yr
Detention
Vol. (ac-ft)
100-Yr
Detention
WSEL (ft)
Peak
Release
(cfs)
Detention Pond 15.96 45 1.78 4,986.07 8.60
INLET CAPACITY SUMMARY
Design
Point Design Inlet Label Q2 Q100 Q100 Total Q100
Intercepted
Q100
Unintercepted Inlet Type Inlet Size
A1 INLET A4-1 0.38 1.75 1.75 1.75 0.00 Nyloplast Basin Dome Grate 12"
A1 INLET A5-1 0.38 1.75 1.75 1.75 0.00 Nyloplast Basin Dome Grate 12"
A2 INLET A6 1.15 5.19 5.19 5.19 0.00 Type 13 Combo Single
A2 INLET A7 1.15 5.19 5.19 5.19 0.00 Type 13 Combo Single
Rain Garden Summay
Min. Flat Area (sf)Req. Vol. (cf)
Prov. Flat Area
(sf)Prov. Vol. (cf)
Imp. Area Treated
(sf)
RAIN GARDEN A 1,243 2,041 1,406 2,145 62,426
RAIN GARDEN B 4,797 6,552 5,207 6,619 237,558
SWALE SUMMARY TABLE
SWALE ID MIN D MIN TW S1 (n:1)BW S2 (n:1)Q Q*1.33
A1 - A1 0.71 38.39 25.0 n/a 13.0 8.68 11.54
A2 - A2 1.57 42.46 18.0 4.0 5.0 47.20 62.78
A3 - A3 0.77 122.09 7.0 4.0 200.0 14.66 19.50
W
W
T
W
X
X
X
X
X
X
X
X X X X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X X X
XXX X
UD UD
UD
UD
UD
8"
S
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8"
S
S
8"
S
S
8"
S
S
8"
S
S
8"
S
S
8" SS 8" SS 8" SS 8" SS 8" SS
8"
S
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8"
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8"
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A2
A3A3
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MOLLER STREET
SAINT GRACE STREET
PITT, JEAN
GBP LLC
PEREZ DANIEL A.
PEREZ DANIEL A.
SOFT GOLD PARK
PROPOSED DETENTION POND
100-YR DETENTION VOLUME = 1.91 AC-FT
100-YR WSEL= 4989.11
PROPERTY
BOUNDARY
PROPERTY
BOUNDARY
PROPOSED POND
OUTLET STRUCTURE
PROPOSED 2'
CONCRETE PAN
PROPOSED 2'
CONCRETE PAN
PROPOSED 4'
SIDEWALK CULVERT
PROPOSED 2'
CONCRETE PAN
RAIN GARDEN A
BIOMEDIA AREA
RAIN GARDEN B
BIOMEDIA AREA
STORM DRAIN A
SEE SHEET ST1
STORM DRAIN C
SEE SHEET ST2
STORM DRAIN B
SEE SHEET ST2
RG A UNDERDRAIN
RG B UNDERDRAIN
0.71 ac.
B1
0.77 ac.
A1
0.19 ac.
OS6
2.32 ac.
A
2.81 ac.
B2
1.29 ac.
A2
INLET A7
INLET A6
STMH A2 w/ WEIR
INLET A4-1
INLET A3-1
KEYMAP
T
WEST WILLOX LANE
HICKORY STREET
SOFT
GOLD PARK
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60
NORTH
( IN FEET )
1 inch = ft.
Feet04040
40
80 120
1.REFER TO THE "FINAL DRAINAGE REPORT DATED APRIL 25, 2025" BY EPS GROUP
FOR ADDITIONAL INFORMATION.
2.THE WILLOX FARM PROJECT WILL BE DETAINING THE DIFFERENCE BETWEEN THE
HISTORIC 2-YEAR EVENT AND THE DEVELOPED 100-YEAR EVENT.
3.LID MEASURES IS PROVIDED VIA RAIN GARDEN.
4.ALL PROPOSED STORM SEWER ARE TO BE PRIVATELY OWNED AND MAINTAINED.
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION 11
NOTES:
A
LEGEND:
MATCH LINE - SEE SHEET DR2
DR3
DR2
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
before you dig.Call
R
SWALE SECTIONS
DEVELOPED DRAINAGE SUMMARY
Design
Point Basin ID
Total
Area
(acres)
C2 C100 2-Yr Tc
(min)
100-Yr
Tc (min)WQ Q2
(cfs)
Q100
(cfs)
a1 A1 0.77 0.44 0.55 10.47 10.47 0.38 0.76 3.50
a2 A2 1.29 0.65 0.81 5.72 5.72 1.15 2.30 10.38
a3 A3 2.40 0.30 0.37 9.85 9.85 0.81 1.62 7.19
b1 B1 0.71 0.55 0.69 5.00 5.00 0.56 1.11 4.85
b2 B2 2.81 0.60 0.75 6.54 6.54 2.20 4.40 21.10
b3 B3 1.17 0.41 0.51 10.83 10.83 0.51 1.03 4.76
b4 B4 1.74 0.50 0.62 10.93 10.93 0.94 1.89 8.72
b5 B5 3.65 0.64 0.80 10.08 10.08 2.58 5.16 25.06
b6 B6 0.86 0.35 0.44 6.49 6.49 0.40 0.80 3.63
b7 B7 0.56 0.73 0.91 5.60 5.60 0.56 1.12 5.05
Offsite Basins
os1 OS1 3.92 0.20 0.20 13.06 13.06 0.78 1.55 5.43
os2 OS2 0.53 0.54 0.54 12.27 12.27 0.29 0.59 2.05
os3 OS3 0.07 0.78 0.78 5.00 5.00 0.08 0.16 0.56
os4 OS4 0.17 0.58 0.58 5.00 5.00 0.14 0.27 0.96
os5 OS5 0.33 0.20 0.20 6.87 6.87 0.09 0.17 0.60
os6 OS6 0.19 0.23 0.23 5.28 5.28 0.06 0.13 0.44
os7 OS7 1.34 0.20 0.20 11.39 11.39 0.29 0.58 2.03
POND SUMMARY TABLE
Pond ID Tributary
Area (ac)
Avg. Percent
Imperviousness
(%)
100-Yr
Detention
Vol. (ac-ft)
100-Yr
Detention
WSEL (ft)
Peak
Release
(cfs)
Detention Pond 15.96 45 1.78 4,986.07 8.60
INLET CAPACITY SUMMARY
Design
Point Design Inlet Label Q2 Q100 Q100 Total Q100
Intercepted
Q100
Unintercepted Inlet Type Inlet Size
A1 INLET A4-1 0.38 1.75 1.75 1.75 0.00 Nyloplast Basin Dome Grate 12"
A1 INLET A5-1 0.38 1.75 1.75 1.75 0.00 Nyloplast Basin Dome Grate 12"
A2 INLET A6 1.15 5.19 5.19 5.19 0.00 Type 13 Combo Single
A2 INLET A7 1.15 5.19 5.19 5.19 0.00 Type 13 Combo Single
Rain Garden Summay
Min. Flat Area (sf)Req. Vol. (cf)
Prov. Flat Area
(sf)Prov. Vol. (cf)
Imp. Area Treated
(sf)
RAIN GARDEN A 1,243 2,041 1,406 2,145 62,426
RAIN GARDEN B 4,797 6,552 5,207 6,619 237,558
SWALE SUMMARY TABLE
SWALE ID MIN D MIN TW S1 (n:1)BW S2 (n:1)Q Q*1.33
A1 - A1 0.71 38.39 25.0 n/a 13.0 8.68 11.54
A2 - A2 1.57 42.46 18.0 4.0 5.0 47.20 62.78
A3 - A3 0.77 122.09 7.0 4.0 200.0 14.66 19.50