HomeMy WebLinkAboutTAPESTRY - PDP240001 - SUBMITTAL DOCUMENTS - ROUND 1 - Drainage Related Document
PRELIMINARY DRAINAGE REPORT
TAPESTRY
FORT COLLINS, COLORADO
APRIL 24, 2024
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FORT COLLINS
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April 24, 2024
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
RE: PRELIMINARY DRAINAGE REPORT FOR
TAPESTRY
Dear Staff:
Northern Engineering/EPS Group is pleased to submit this Preliminary Drainage Report for your review. This report
accompanies the preliminary submittal for the proposed Tapestry project.
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 project. We understand that review by the City of Fort
Collins is to assure general compliance with standardized criteria contained in the FCSCM.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
STEPHANIE THOMAS, PE JACOB O’BANION, EIT
Project Manager Project Engineer
Compliance Statement
I hereby attest that this report for the final drainage design for Tapestry was prepared by me or under my direct
supervision, in accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I understand that
the City of Fort Collins does not and will not assume liability for drainage facilities designed by others.
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TABLE OF CONTENTS
GENERAL LOCATION AND DESCRIPTION ................................................................. 1
DRAIN BASINS AND SUB-BASINS ............................................................................. 3
DRAINAGE DESIGN CRITERIA ................................................................................... 4
DRAINAGE FACILITY DESIGN .................................................................................... 6
CONCLUSIONS ......................................................................................................... 12
REFERENCES ............................................................................................................ 13
TABLES AND FIGURES
FIGURE 1 – AERIAL PHOTOGRAPH ...................................................................................1
FIGURE 2 – FEMA FIRMETTE .............................................................................................3
FIGURE 3 – EXISTING CITY FLOODPLAINS .......................................................................3
TABLE 1 – RATIONAL CALCULATIONS SUMMARY ......................................................... 11
TABLE 2 - DETENTION SUMMARY .................................................................................. 12
APPENDICES
APPENDIX A – HYDROLOGIC COMPUTATIONS
APPENDIX B – HYDRAULIC CALCULATIONS
APPENDIX C –WATER QUALITY/LID COMPUTATIONS
APPENDIX D – EROSION CONTROL REPORT
APPENDIX E – USDA SOILS REPORT
APPENDIX F – SIGNED VARIANCE APPLICATION
MAP POCKET
DR1 – DRAINAGE EXHIBIT
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GENERAL LOCATION AND DESCRIPTION
A. LOCATION
Vicinity Map
The Tapestry project site is a parcel of land being a portion of the northeast ¼ of Section 12,
Township 7 north, range 69 west of the 6th P.M. City of Fort Collins, County of Larimer, State of
Colorado.
The project site (refer to Figure 1) is bordered to the north by Buckingham Street and the New
Belgium Brewery property; to the west by 3rd Street and an existing single-family residential area
(Buckingham Neighborhood); to the south by Odell Brewing Company; and to the east by Colorado
Iron and Metal.
B. DESCRIPTION OF PROPERTY
The project site is a ± 11.1-acre tract.
The site is currently undeveloped and zoned as Industrial District (I).
The existing groundcover consists of grass, dirt, and beet tailings with a few trees along the outer
edge of the subject property. The existing topography is characterized by Loveland clay loam soil
overlaid with a layer of beet tailings. The beet tailings consist of the residual material left behind
from sugar beet processing, resulting in irregular mounds, depressions and ridges across the
Figure 1 – Aerial Photograph
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landscape. The presence of beet tailings adds an additional layer of complexity to the site’s
drainage dynamics. In order to avoid considering the presence of the beet tailings when assessing
the existing drainage conditions, a new surface was designed and approved by The City of Fort
Collins with the beet tailings removed. This plan set is called “Utility Plans for Odell – North” and
was approved on 01/09/2022. The topography from the approved design is the topography used
to assess the existing drainage conditions for the subject property. Therefore the approved surface
design of the beet tailing removal will be referred to as the existing surface throughout the the
remainder of this report. The plans for the beet tailing removal surface are included as an
attachment with this report.
The existing on-site runoff generally drains from north to south across flat grades (e.g., < 1.00%).
The site drains to an existing 6” pvc just north of the Odell Brewing Company parking lot and south
of the subject property. The existing storm drain discharges to Lincoln Avenue. A geotechnical
investigation was conducted on the project site in March of 2021 and ground water was found to
be between 10-14 feet below the existing surface (prior to beet tailing removal). It was estimated
that the general flow of the groundwater on site is to the southeast.
According to the United States Department of Agriculture (USDA) Natural Resources Conservation
Service (NRCS) Soil Survey, the site consists primarily of Loveland clay loams which fall into
Hydrologic Soil Group C.
The proposed development consists of 7 – 20-unit condominiums, open space, private alleys, and
a connector local street that is a continuance of Logan Avenue from the west side of the site at 3 rd
Street and ties into Buckingham Street as 4th Street, a connector local street.
The proposed land use is Multi-Family Residential and two future development tracts.
C. FLOODPLAIN
The entirety of the subject property is located within the FEMA 500-yr floodplain (Zone X), LOMR
20-08-0643P effective 06/25/2021. FEMA has designated 3rd street (west of the subject property)
and a large portion of the Odell site (south of the property as Reduced Flood Risk due to Levee
(Zone X), LOMR 06-08B336P effective 04/19/2007.
The entirety of the subject property is located within a City of Fort Collins Moderate Risk 100-yr
floodplain.
a) As per section 10-103 (9), Critical Facilities are prohibited in the floodplain. The definition of
Critical Facilities includes facilities for at-risk populations (daycares, schools, nursing homes,
etc.), facilities utilizing hazardous materials (gas stations, auto repair, laboratories),
emergency services facilities (urgent care, hospitals, fire, police) and government services
(municipal offices, library). A floodplain use permit is required prior to building permit
issuance.
b) Development within the floodplain must comply with Chapter 10 of the Municipal Code.
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Figure 2 – FEMA FIRMette
Figure 3 – Existing City Floodplains
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DRAIN BASINS AND SUB-BASINS
A. MAJOR BASIN DESCRIPTION
a) The Tapestry project is located within the Dry Creek Basin. The Dry Creek Basin is a tributary of the
Cache la Poudre River. The basin begins near the Wyoming border, has a drainage area of about 62
square miles with a series of irrigation canals and reservoirs dominating the upper basin. The
majority of the lower basin is developed and includes commercial, industrial and residential uses.
Dry Creek enters Fort Collins near Willox Lane and College Avenue and flows through small
remnants of ditches and channels until it joins the Cache la Poudre River near Mulberry Street and
Timberline Road. The runoff from the Tapestry project generally flows from north to south and
ultimately ends up within the Cache la Poudre River south of Lincoln Avenue.
B. SUB-BASIN DESCRIPTION
The project site is broken up into fifteen sub-basins. The B, C and D basins are captured by on-site
inlets and conveyed through storm drains and are treated via Stormtech isolator chambers
throughout the site and ultimately discharged to the proposed detention pond. The A, E, F, G and
P basins are captured by on-site inlets and conveyed through storm drains or flow via concrete pans
or sheet flow to the proposed detention pond. The project site has one outfall location which is
the outfall structure on the southern end of the proposed detention pond. The flows from the site
are conveyed from the proposed detention pond via storm sewer that ties into an existing storm
drain in the northeast corner of the Odell property.
The project site does not receive notable runoff from contiguous off-site properties.
DRAINAGE DESIGN CRITERIA
A. STORMWATER MANAGEMENT STRATEGY
The overall stormwater management strategy employed with the Tapestry project utilizes the “Four
Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a
description of how the proposed development has incorporated each step.
Step 1 – Employ Runoff Reduction Practices. The Tapestry project aims to reduce runoff peaks,
volumes and pollutant loads from frequently occurring storm events (i.e., water quality (i.e., 80th
percentile) and 2-year storm events) by implementing Low Impact Development (LID) strategies.
Wherever practical, runoff will be routed across landscaped areas. The project has also implemented
Stormtech isolator chambers throughout the site that serve to capture, treat and release runoff from
new impervious areas. The project has also made an effort to increase the amount of open space
wherever feasible on site in order to minimize imperviousness on-site. These LID practices reduce the
overall amount of impervious area, while at the same time Minimizing Directly Connected Impervious
Areas (MDCIA). The combined LID/MDCIA techniques will be implemented, where practical,
throughout the development, thereby slowing runoff and increasing opportunities for infiltration.
Step 2 – Implement 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, urban development of this intensity will still have stormwater runoff leaving the site.
The primary water quality treatment will occur via Stormtech isolator chambers that will ultimately
discharge to the proposed detention pond. In addition to LID treatment, traditional water quality
treatment will be provided within the lower stages of the detention pond.
Step 3 – Stabilize Drainageways. The Tapestry project aims to protect the existing Cache La Poudre
River by limiting any increases beyond historical flow rates within the river. By utilizing a combination
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of LID, traditional water quality treatment, and a detention pond. As such, the peak discharge from the
Tapestry project will not be compounded with peak flow in the river. Furthermore, this project will pay
a one-time stormwater development fee, as well as ongoing monthly utility fees, both of which help
achieve citywide drainage stability.
Step 4 – Implement Site Specific and Other Source Control BMPs. This step typically applies to
industrial and commercial developments. This does not apply to this site.
B. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
The site plan is constrained topographically on the north and west by Buckingham Street and 3 rd
Street respectively, on the east side by the Colorado Iron and Metal property, and to the south by
the Odell property.
The site is constrained by the amount of beet tailing remediation that is required. Beet remediation
will lower the existing site topography creating a sumped site. A substantial amount of fill will be
required in order to allow the site to drain and to allow for detention and water quality treatment.
C. HYDROLOGICAL CRITERIA
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 Tapestry
development. Data contained in Table 3.4-1 has been utilized for Rational Method runoff
calculations.
The Rational Method has been employed to compute stormwater runoff utilizing coefficients
contained in Tables 4.1-2 and 4.1-3 of the FCSCM.
Three separate design storms have been utilized to address distinct drainage scenarios. The first
event analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The second
event considered is the “Major Storm,” which has a 100-year recurrence interval. The final event
analyzed was the 10-year recurrence interval for comparative analysis only.
D. HYDRAULIC CRITERIA
The drainage facilities proposed with the Tapestry development project are designed in
accordance with criteria outlined in the Mile High Flood District’s “Urban Storm Drainage Criteria
Manual” (UDFCD) and the Fort Collins Stormwater Criteria Manual (FCSCM).
As stated in Section I.C, above, the subject property is located within the FEMA 500-yr floodplain
and within the City moderate risk 100-yr floodplain. Therefore a floodplain use permit is required
prior to building permit issuance and development within the floodplain must comply with
Chapter 10 of the Municipal Code.
E. CONFORMANCE WITH WATER QUALITY TREATMENT CRITERIA
City Code requires that 100% of runoff from a project site receive some sort of water quality treatment.
This project proposes to provide water quality treatment using underground Stormtech isolator
chambers and traditional water quality within the lower stages of the detention pond. Through these
methods 100% of the on-site area will be treated for water quality.
F. CONFORMANCE WITH LOW IMPACT DEVELOPMENT (LID)
The project site will conform with the requirement to treat a minimum of 75% of the proposed
impervious surfaces using LID treatment from Stormtech isolator chambers. Please see Appendix C for
LID design information, table, and exhibit(s). This project proposes to provide LID treatment by using
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an underground infiltration gallery (aka – underground chambers) located throughout the project site.
Stormtech isolator chambers are considered a LID treatment method. Due to the physical constraints
associated with the project some areas cannot be captured and adequately routed to the Stormtech
chambers. However, these areas are designated to receive water quality treatment within the proposed
detention pond.
G. SIZING OF WATER QUALITY AND LID FACILITIES
Stormtech Isolator Chambers
The Stormtech isolator chambers were sized by first determining the required water quality capture
volume (WQCV) for each Stormtech isolator chamber. A 12-Hour drain time was used in these
calculations. Once the WQCV was identified, the minimum number of chambers needed to achieve
this volume was calculated. Using the FAA method, another volume calculation was performed
utilizing the WQ flow rate into the chamber and calculated release rate through the fabric. The
number of chambers has been increased as needed to confirm the resulting FAA volume is
provided within the empty volume of the underground chambers. This is intended to ensure the
chambers do not become overwhelmed in the water quality storm event before “discharging”
flows into surrounding aggregates. A summary of these calculations and volumes can be found in
Appendix C.
While the purpose of these LID systems is to treat the water quality storm event, the Stormtech
isolator chambers were designed to bypass flows from the major storm event.
Each isolator row will have an inspection port and a Nyloplast basin at the end for easy maintenance
and cleanout.
Water Quality Extended Detention
Traditional water quality treatment is provided for all areas not treated by LID or expected to be
treated by LID in the future. The water quality extended detention volume was determined by
first determining the tributary area that needs to be treated and its percent imperviousness. The
tributary area used for determining the WQCV in the detention pond consists of basins A1, A2, E1,
25% of fully developed F1, 25% of fully developed G1, and P. A 40-hour drain time was used in
this calculation. The WQCV was then multiplied by 1.2 per FCSCM.
It is expected that the future developments within basins F1 and G1 will be required to treat the
remaining 75% of their impervious area through an approved LID treatment.
DRAINAGE FACILITY DESIGN
A. GENERAL CONCEPT
The main objective of the Tapestry project drainage design is to bring the project site into
compliance with the Mile High Flood District’s “Urban Storm Drainage Criteria Manual” (UDFCD)
and the Fort Collins Stormwater Criteria Manual (FCSCM).
A list of tables and figures used within this report can be found in the Table of Contents at the front
of the document. The tables and figures are located within the sections to which the content best
applies.
Drainage for the project site has been analyzed using fifteen (15) major storm event drainage sub-
basins. Within those basins there are five (5) minor storm event drainage sub-basins. The minor
storm event drainage sub-basins consist of only roofs. During major storm events the roof drains
are assumed to be overwhelmed therefore the runoff from the roofs would be directed to the inlet
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within the major basin. A small percentage of the flow would continue to the stormwater
infrastructure for which the minor event subbasin is designated. During minor storm events these
basins are assumed to drain to roof drains that are routed to storm infrastructure outside of the
major basin. The drainage patterns anticipated for the sub-basins are further described below.
Proposed Basins
Basin A1
Basin A1 encompasses streets, buildings, landscape, and walks internal to the site. Runoff from
Basin A1 is captured by inlets within Basin A1 and is conveyed to the proposed Detention Pond.
The runoff from Basin A1 is accounted for in the detention volume and the extended water quality
detention volume.
Basin A2
Basin A2 encompasses streets, landscape, and walks internal to the site. Runoff from Basin A2 is
captured by inlets within Basin A2 and is conveyed to the proposed Detention Pond. The runoff
from Basin A2 is accounted for in the detention volume and the extended water quality detention
volume.
Basin B1
Basin B1 encompasses parking lots, buildings, landscape, and walks internal to the site. Runoff from
Basin B1 is captured by inlets within Basin B1 and is conveyed to Underground Chambers 1 for
water quality treatment. During a major storm event, the runoff from Basin B1 is routed over a weir
that directs the flow through the downstream storm infrastructure to the Detention Pond. The
runoff from Basin B1 is accounted for in the detention volume.
Basin B2
Basin B2 encompasses parking lots, buildings, landscape, and walks internal to the site. Runoff from
Basin B2 is captured by inlets within Basin B2 and is conveyed to Underground Chambers 1 for
water quality treatment. During a major storm event, the runoff from Basin B2 is routed over a weir
that directs the flow through the downstream storm infrastructure to the Detention Pond. The
runoff from Basin B2 is accounted for in the detention volume. A small portion of Basin B2 is
rerouted to storm infrastructure in Basin D1 during a water quality/minor storm event. Please see
Basins D1.1 and D1.2 for more details.
Basin C1
Basin C1 encompasses a portion of 3rd street, as well as, buildings, landscape, and walks internal to
the site. Runoff from Basin C1 is captured by inlets within Basin C1 and is conveyed to Underground
Chambers 2 for water quality treatment. During a major storm event, the runoff from Basin C1 is
routed over a weir that directs the flow through the downstream storm infrastructure to the
Detention Pond. The runoff from Basin C1 is accounted for in the detention volume.
Basin C2
Basin C2 encompasses parking lots, buildings, landscape, and walks internal to the site. Runoff from
Basin C2 is captured by inlets within Basin C2 and is conveyed to Underground Chambers 2 for
water quality treatment. During a major storm event, the runoff from Basin C2 is routed over a weir
that directs the flow through the downstream storm infrastructure to the Detention Pond. The
runoff from Basin C2 is accounted for in the detention volume.
Basin D1
Basin D1 encompasses parking lots, buildings, landscape, and walks internal to the site. Runoff
from Basin D1 is captured by inlets within Basin D1 and is conveyed to Underground Chambers 3
for water quality treatment. During a major storm event, the runoff from Basin D1 is routed over a
weir that directs the flow through the downstream storm infrastructure to the Detention Pond. The
runoff from Basin D1 is accounted for in the detention volume. A small portion of Basin D1 is
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rerouted to storm infrastructure in Basin C2 during a water quality/minor storm event. Please see
Basin C2.1 for more details.
Basin D2
Basin D2 encompasses parking lots, buildings, landscape, and walks internal to the site. Runoff
from Basin D2 is captured by inlets within Basin D2 and is conveyed to Underground Chambers 4
for water quality treatment. During a major storm event, the runoff from Basin D2 is routed over a
weir that directs the flow through the downstream storm infrastructure to the Detention Pond. The
runoff from Basin D2 is accounted for in the detention volume. A small portion of Basin D2 is
rerouted to storm infrastructure in Basin D1 during a water quality/minor storm event. Please see
Basin D1.4 for more details.
Basin D3
Basin D3 encompasses a park, buildings, landscape, and walks internal to the site. Runoff from
Basin D3 is captured by inlets within Basin D3 and is conveyed to Underground Chambers 4 for
water quality treatment. During a major storm event, the runoff from Basin D3 is routed over a weir
that directs the flow through the downstream storm infrastructure to the Detention Pond. The
runoff from Basin D3 is accounted for in the detention volume. A small portion of Basin D3 is
rerouted to storm infrastructure in Basin D2 during a water quality/minor storm event. Please see
Basin D1.3 for more details.
Basin D4
Basin D4 encompasses streets, walks and landscape. Runoff from Basin D4 is captured by inlets
within Basin D4 and is conveyed to Underground Chambers 4 for water quality treatment. During
a major storm event, the runoff from Basin D4 is routed over a weir that directs the flow through
the downstream storm infrastructure to the Detention Pond. The runoff from Basin D4 is accounted
for in the detention volume.
Basin D5
Basin D5 encompasses streets, walks and landscape. Runoff from Basin D5 is captured by inlets
within Basin D5 and is conveyed to Underground Chambers 4 for water quality treatment. During
a major storm event, the runoff from Basin D5 is routed over a weir that directs the flow through
the downstream storm infrastructure to the Detention Pond. The runoff from Basin D5 is accounted
for in the detention volume.
Basin E1
Basin E1 encompasses a portion of Buckingham Street, as well as buildings, landscape, and walks
internal to the site. Runoff from Basin E1 is captured by a sidewalk culvert within Basin E1 and is
conveyed to the proposed Detention Pond. The runoff from Basin E1 is accounted for in the
detention volume and the extended water quality detention volume.
Basin F1
Basin F1 is considered undeveloped for the interim condition. In the interim condition, runoff will
flow from west to east to a proposed drainage pan where it will be conveyed to the proposed
Detention Pond. See Basin Future F1 for more information.
Basin G1
Basin G1 is considered undeveloped for the interim condition. In the interim condition, runoff will
continue, as historically, to flow off-site to storm infrastructure in the Odell parking lot. See Basin
Future G1 for more information.
Basin P
Basin P is comprised of the detention pond. Runoff stored in the pond is discharged through an
outlet structure and storm drain that ties into an existing storm drain southeast of the project site.
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Future Development Basins
Basin Future F1
Basin Future F1 is considered to be commercial land use in the future condition. Runoff from this
future developed basin is accounted for in the detention volume.
Basin Future G1
Basin Future G1 is considered to be commercial land use in the future condition. Runoff from this
future developed basin is accounted for in the detention volume.
Minor Storm Event Basins
Basin C2.1
Basin C2.1 is comprised entirely of a portion of roof within Basin D1. The runoff within this basin is
expected to drain to the stormwater infrastructure in Basin D1 during a major event, but is
expected to be directed to the stormwater infrastructure in Basin C2 during a water quality/minor
event.
Basin D1.1
Basin D1.1 is comprised entirely of a portion of roof within Basin B2. The runoff within this basin is
expected to drain to the stormwater infrastructure in Basin B2 during a major event, but is expected
to be directed to the stormwater infrastructure in Basin D1 during a water quality/minor event.
Basin D1.2
Basin D1.2 is comprised entirely of a portion of roof within Basin B2. The runoff within this basin is
expected to drain to the stormwater infrastructure in Basin B2 during a major event, but is expected
to be directed to the stormwater infrastructure in Basin D1 during a water quality/minor event.
Basin D1.3
Basin D1.3 is comprised entirely of a portion of roof within Basin D3. The runoff within this basin is
expected to drain to the stormwater infrastructure in Basin D3 during a major event, but is
expected to be directed to the stormwater infrastructure in Basin D1 during a water quality/minor
event.
Basin D1.4
Basin D1.4 is comprised entirely of a portion of roof within Basin D2. The runoff within this basin is
expected to drain to the stormwater infrastructure in Basin D2 during a major event, but is
expected to be directed to the stormwater infrastructure in Basin D1 during a water quality/minor
event.
Combined Basins
Future
The FUTURE basin consists of basins A1, A2, B1, B2, C1, C2, D1, D2, D3, D4, D5, E1, F1 FUTURE, G1
FUTURE, and P. This combined basin was used to determine the volume of the detention pond.
WQCV
The WQCV basin consists of basins A1, A2, E1, F1 FUTURE, G1 FUTURE, and P. This combined basin
was used to determine the WQCV volume within the detention pond. Note that only 25% of F1
FUTURE and 25% of G1 FUTURE were used in determining the WQCV.
UG1
The UG1 basin consists of basins B1 and B2. The runoff from this basin is conveyed to Underground
Chambers 1 and was used in determining the size of Underground Chambers 1.
UG2
The UG2 basin consists of basins C1 and C2. The runoff from this basin is conveyed to Underground
Chambers 2.
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UG3
The UG3 basin consists of basin D1. The runoff from this basin is conveyed to Underground
Chambers 3.
UG4
The UG4 basin consists of basins D2, D3, D4 and D5. The runoff from this basin is conveyed to
Underground Chambers 4 and was used in determining the size of Underground Chambers 4.
UG1*
The UG1* basin consists of basins B1 and B2. Note that Minor Basins D1.1 and D1.2 were subtracted
from calculations of Basin B2. The runoff from this basin is conveyed to Underground Chambers 1
during the minor storm event.
UG2*
The UG2* basin consists of basins C1, C2 and C2.1. The runoff from this basin is conveyed to
Underground Chambers 2 during the minor storm event. The runoff from this basin was used to
determine the size of Underground Chambers 2.
UG3*
The UG3* basin consists of basins D1, D1.1, D1.2, D1.3, and D1.4. Note that Minor Basin C2.1 was
subtracted from calculations of Basin D1. The runoff from this basin is conveyed to Underground
Chambers 3 during the minor storm event. The runoff from this basin was used to determine the
size of Underground Chambers 3.
UG4*
The UG4* basin consists of basins D2, D3, D4 and D5. Note that Minor Basin D1.3 was subtracted
from the calculations of Basin D3 and Minor Basin D1.4 was subtracted from the calculations of D2.
The runoff from this basin is conveyed to Underground Chambers 4 during the minor storm event.
The underground chambers were sized to account for the most conservative scenario between the
UG and UG* basins.
Basin ID Design
Point
Total
Area
(acres)
C2 C100 2-Yr Tc
(min)
100-Yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
Proposed Basins
A1 a1 0.50 0.76 0.95 5.00 5.00 1.07 4.67
A2 a2 0.33 0.80 1.00 5.00 5.00 0.76 3.31
B1 b1 0.66 0.82 1.00 5.00 5.00 1.55 6.59
B2 b2 0.97 0.88 1.00 5.00 5.00 2.46 9.69
C1 c1 1.29 0.74 0.92 5.53 5.00 2.61 11.77
C2 c2 0.61 0.86 1.00 5.00 5.00 1.49 6.05
D1 d1 0.73 0.89 1.00 5.00 5.00 1.85 7.22
D2 d2 0.23 0.90 1.00 5.00 5.00 0.59 2.30
D3 d3 1.11 0.50 0.62 10.89 8.88 1.20 5.69
D4 d4 0.21 0.77 0.96 5.00 5.00 0.45 1.96
D5 d5 0.21 0.79 0.98 5.00 5.00 0.46 2.01
E1 e1 1.24 0.77 0.96 6.16 5.00 2.55 11.87
F1 f1 1.15 0.21 0.26 12.17 12.17 0.50 2.17
G1 g1 1.26 0.20 0.25 11.67 11.67 0.53 2.29
P p 1.49 0.21 0.26 10.67 10.09 0.67 3.00
Future Development Basins
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Basin ID Design
Point
Total
Area
(acres)
C2 C100 2-Yr Tc
(min)
100-Yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
F1
FUTURE
f1
future 1.15 0.85 1.00 5.00 5.00 2.79 11.46
G1
FUTURE
g1
future 1.26 0.85 1.00 5.00 5.00 3.05 12.51
Minor Storm Event Sub-Basins
C2.1 c2.1 0.04 0.95 n/a 5.00 5.00 0.11 n/a
D1.1 d1.1 0.01 0.95 n/a 5.00 5.00 0.04 n/a
D1.2 d1.2 0.04 0.95 n/a 5.00 5.00 0.10 n/a
D1.3 d1.3 0.16 0.95 n/a 5.00 5.00 0.43 n/a
Combined Basins
FUTURE future 11.98 0.71 0.89 11.13 7.80 18.23 91.89
WQCV wqcv 5.97 0.41 0.51 11.65 10.53 5.06 22.89
UG1 ug1 1.64 0.86 1.00 5.00 5.00 4.01 16.28
UG2 ug2 1.89 0.78 0.97 5.85 5.00 4.05 18.26
UG3 ug3 0.73 0.89 1.00 5.00 5.00 1.85 7.22
UG4 ug4 1.75 0.62 0.77 10.51 7.64 2.35 11.61
Combined Basins Minor Storm Event
UG1* ug1* 1.59 0.86 n/a 5.00 N/A 3.87 n/a
UG2* ug2* 1.94 0.78 n/a 5.82 N/A 4.16 n/a
UG3* ug3* 0.97 0.91 n/a 5.00 N/A 2.50 n/a
UG4* ug4* 1.52 0.57 n/a 11.46 N/A 1.83 n/a
Table 1 – Rational Calculations Summary
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report.
B. SPECIFIC DETAILS
The Tapestry project plan is constrained on the north and west by Buckingham Street and 3rd Street
respectively, on the east side by the Colorado Iron and Metal property, and to the south by the
Odell property. The site will be discharging from the proposed detention pond to an existing storm
drain southeast of the project site. In order to reduce runoff peaks, volumes and pollutant loads
from urbanizing areas, LID strategies and a detention pond are proposed.
The Tapestry project proposes providing 100-year detention at a specified release rate of 0.20
cfs/acre and utilizing extended detention for water quality.
Stormtech isolator chambers are proposed to treat on-site runoff and conform with LID practices
established in the UDFCD and Fort Collins Stormwater Criteria Manual.
Detention Pond Calculations:
a) Detention Pond Calculations were done via FAA Modified method as described in Chapter 6,
Section 2.3 in the City of Fort Collins Stormwater Criteria Manual.
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Pond ID Tributary
Area (ac)
Weighted
Percent
Imperviousness
(%)
Extended
Detention
WQCV (ac-
ft)
100-Yr
Detention
Vol. (ac-ft)
Total Pond
Volume
(ac-ft)
100-Yr
Detention
WSEL (ft)
Final
Release
Rate
(cfs)
Detention
Pond 11.98 66 0.10 2.85 2.95 4,949.44 2.40
Table 2 - Detention Summary
CONCLUSIONS
A. COMPLIANCE WITH STANDARDS
The detention design proposed with the Tapestry project does comply with the City of Fort
Collins’ Stormwater Criteria Manual.
The drainage plan and stormwater management measures proposed with the Tapestry project are
compliant with all applicable State and Federal regulations governing stormwater discharge.
B. DRAINAGE CONCEPT
The drainage design proposed with this project will effectively limit potential damage associated
with its stormwater runoff.
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REFERENCES
1. 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.
2. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No.
159, 2018, and referenced in Section 26-500 of the City of Fort Collins Municipal Code.
3. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service,
United States Department of Agriculture.
4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District,
Wright-McLaughlin Engineers, Denver, Colorado, Revised January 2016. Mile High Flood District,
Updated March 2024.
5. Phase 1 Environmental Site Assessment Odell Townhomes Corner of Buckingham and 3 rd Street Fort
Collins, Colorado, Project No. FC10679-200 January 12, 2023, Fort Collins, Colorado.
6. Utility Plans for Odell -North, Northern Engineering, Approved January 9, 2022.
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APPENDIX A
HYDROLOGIC COMPUTATIONS
Runoff Coefficient1
Percent
Impervious1 Project:
Location:
0.95 100%Calc. By:
0.95 90%Date:
0.85 80%
0.80 80%
0.50 40%
0.50 40%
0.20 2%
Basin ID Basin Area
(sq.ft.)
Basin Area
(acres)
Asphalt, Concrete
(acres)Rooftop (acres)Commercial
(acres)Gravel (acres)Recycled Asphalt
(acres)Pavers (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 21,615 0.50 0.21 0.16 0.00 0.00 0.00 0.00 0.13 72% 0.76 0.76 0.76 0.95
A2 14,521 0.33 0.27 0.00 0.00 0.00 0.00 0.00 0.07 80% 0.80 0.80 0.80 1.00
B1 28,844 0.66 0.34 0.20 0.00 0.00 0.00 0.00 0.11 80% 0.82 0.82 0.82 1.00
B2 42,425 0.97 0.51 0.38 0.00 0.00 0.00 0.00 0.08 88% 0.88 0.88 0.88 1.00
C1 56,052 1.29 0.60 0.31 0.00 0.00 0.00 0.00 0.37 69% 0.74 0.74 0.74 0.92
C2 26,477 0.61 0.33 0.20 0.00 0.00 0.00 0.00 0.07 85% 0.86 0.86 0.86 1.00
D1 31,612 0.73 0.45 0.22 0.00 0.00 0.00 0.00 0.06 89% 0.89 0.89 0.89 1.00
D2 10,089 0.23 0.14 0.07 0.00 0.00 0.00 0.00 0.02 90% 0.90 0.90 0.90 1.00
D3 48,426 1.11 0.10 0.30 0.00 0.03 0.04 0.01 0.64 38% 0.50 0.50 0.50 0.62
D4 8,968 0.21 0.16 0.00 0.00 0.00 0.00 0.00 0.05 76% 0.77 0.77 0.77 0.96
D5 8,933 0.21 0.16 0.00 0.00 0.00 0.00 0.00 0.04 79% 0.79 0.79 0.79 0.98
E1 53,951 1.24 0.64 0.31 0.00 0.00 0.00 0.00 0.30 74% 0.77 0.77 0.77 0.96
F1 50,150 1.15 0.02 0.00 0.00 0.00 0.00 0.00 1.13 3% 0.21 0.21 0.21 0.26
G1 54,755 1.26 0.00 0.00 0.00 0.00 0.00 0.00 1.26 2% 0.20 0.20 0.20 0.25
P 64,852 1.49 0.02 0.00 0.00 0.00 0.00 0.00 1.47 3% 0.21 0.21 0.21 0.26
Total 521,669 11.98 3.94 2.16 0.00 0.03 0.04 0.01 5.80 50% 0.58 0.58 0.58 0.73
F1 FUTURE 50,150 1.15 0.00 0.00 1.15 0.00 0.00 0.00 0.00 80% 0.85 0.85 0.85 1.00
G1 FUTURE 54,755 1.26 0.00 0.00 1.26 0.00 0.00 0.00 0.00 80% 0.85 0.85 0.85 1.00
Total 104,905 2.41 0.00 0.00 2.41 0.00 0.00 0.00 0.00 80% 0.85 0.85 0.85 1.00
C2.1 1,794 0.04 0.00 0.04 0.00 0.00 0.00 0.00 0.00 90% 0.95 n/a n/a n/a
D1.1 604 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.00 90% 0.95 n/a n/a n/a
D1.2 1,554 0.04 0.00 0.04 0.00 0.00 0.00 0.00 0.00 90% 0.95 n/a n/a n/a
D1.3 6,899 0.16 0.00 0.16 0.00 0.00 0.00 0.00 0.00 90% 0.95 n/a n/a n/a
D1.4 3,221 0.07 0.00 0.07 0.00 0.00 0.00 0.00 0.00 90% 0.95 n/a n/a n/a
Total 14,072 0.32 0.00 0.32 0.00 0.00 0.00 0.00 0.00 90% 0.95 0.95 0.95 1.00
FUTURE 521,669 11.98 3.92 2.16 2.41 0.03 0.04 0.01 3.41 66% 0.71 0.71 0.71 0.89
WQCV 259,845 5.97 1.13 0.47 0.60 0.00 0.00 0.00 1.96 35% 0.41 0.41 0.41 0.51
UG1 71,269 1.64 0.85 0.59 0.00 0.00 0.00 0.00 0.20 85% 0.86 0.86 0.86 1.00
UG2 82,529 1.89 0.94 0.51 0.00 0.00 0.00 0.00 0.44 74% 0.78 0.78 0.78 0.97
UG3 31,612 0.73 0.45 0.22 0.00 0.00 0.00 0.00 0.06 89% 0.89 0.89 0.89 1.00
UG4 76,415 1.75 0.55 0.37 0.00 0.03 0.04 0.01 0.75 54% 0.62 0.62 0.62 0.77
UG1* 69,110 1.59 0.85 0.54 0.00 0.00 0.00 0.00 0.20 84% 0.86 n/a n/a n/a
UG2* 84,323 1.94 0.94 0.56 0.00 0.00 0.00 0.00 0.44 75% 0.78 n/a n/a n/a
UG3* 42,096 0.97 0.45 0.46 0.00 0.00 0.00 0.00 0.06 90% 0.91 n/a n/a n/a
UG4* 66,295 1.52 0.55 0.14 0.00 0.03 0.04 0.01 0.75 49% 0.57 n/a n/a n/a
DEVELOPED RUNOFF COEFFICIENT CALCULATIONS
Asphalt, Concrete
Rooftop
Commercial
Recycled Asphalt
Streets, Parking Lots, Roofs, Alleys, and Drives:
Character of Surface:Tapestry
Fort Collins
J. Obanion
April 23, 2024
Pavers 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.
Gravel
Future Development Basins
Proposed Basins
Lawns and Landscaping:
Combined Basins Minor Storm Event 7,8,9,10
Combined Basins 1,2,3,4,5,6
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
Minor Storm Event Sub-Basins
Notes:
1) The FUTURE Basin consists of all the proposed basins and the two future developments in basins F1 and G1. This basin is a combinantion of Basins A1, A2, B1, B2, C1, C2, D1, D3, D4, D5, E1, F1 FUTURE, G1 FUTURE, & P.
2) The WQCV Basin consists of all the basins that will be treated for water quality via extended detention. This basin is a combination of Basins A1, A2, E1, 25% of F1 FUTURE,25% of G1 FUTURE, & P.
3) The UG1 Basin consists of basins B1 & B2 that will be treated through Stormtech Chambers.
4) The UG2 Basin consists of basins C1 & C2 that will be treated through Stormtech Chambers.
5) The UG3 Basin consists of basin D1 that will be treated through Stormtech Chambes.
6) The UG4 Basin consists of basins D2, D3, D4, & D5 that will be treated through Stormtech Chambers.
7) The UG1* Basin consists of basins B1 & B2 that will be treated through Stormtech Chambers. Note that Minor Basin D1.1 & D1.2 were subracted from basin B2 for this calculation.
8) The UG2* Basin consists of basins C1, C2 & Minor Basin C2.1 that will be treated through Stormtech Chambers.
9) The UG3* Basin consists of basins D1, Minor Basin D1.1, Minor Basin D1.2, Minor Basin D1.3 & Minor Basin D1.4 that will be treated through Stormtech Chambers. Note that Minor Basin C2.1 was subtracted from basin D1 for this calculation.
10) The UG4* Basin consists of basins D2, D3, D4, & D5 that will be treated through Stormtech Chambers. Note that Minor Basin D1.3 was subracted from basin D3 for this calculation.
Page 1 of 1
Where:
Length
(ft)
Elev
Up
Elev
Down
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 10-Yr
(min)
Tc
10-Yr
(min)
Comp.
Tc 100-Yr
(min)
Tc
100-Yr
(min)
A1 a1 7 52.25 52.10 2.14%1.32 1.32 0.59 270 0.60% Gutter 0.012 3.61 19.18 0.19 3.16 1.42 11.54 2.74 5.00 2.74 5.00 2.02 5.00
A2 a2 26 53.40 51.82 6.08%1.57 1.57 0.53 220 0.60% Gutter 0.012 3.61 19.18 0.19 3.16 1.16 11.37 2.74 5.00 2.74 5.00 1.69 5.00
B1 b1 33 53.31 52.51 2.42%2.23 2.23 0.80 170 0.50% Valley Pan 0.012 6.00 10.25 0.59 6.14 0.46 11.13 2.69 5.00 2.69 5.00 1.26 5.00
B2 b2 17 53.42 53.01 2.41%1.24 1.24 0.57 295 0.50% Valley Pan 0.012 6.00 10.25 0.59 6.14 0.80 11.73 2.04 5.00 2.04 5.00 1.38 5.00
C1 c1 34 53.66 52.42 3.65%2.58 2.58 1.28 510 0.50% Gutter 0.012 3.61 19.18 0.19 2.88 2.95 13.02 5.53 5.53 5.53 5.53 4.23 5.00
C2 c2
30 52.85 52.10 2.50%1.81 1.81 0.75 290 0.50% Gutter
0.012 3.61 19.18 0.19 2.88 1.68 11.78 3.49 5.00 3.49 5.00 2.43 5.00
D1 d1
25 52.66 51.93 2.92%1.36 1.36 0.65 225 0.50% Gutter
0.012 3.61 19.18 0.19 2.88 1.30 11.39 2.66 5.00 2.66 5.00 1.95 5.00
D2 d2
62 52 50.92 2.10%2.32 2.32 1.15 45 0.50% Gutter
0.012 3.61 19.18 0.19 2.88 0.26 10.59 2.58 5.00 2.58 5.00 1.41 5.00
D3 d3
160 53.11 49.84 2.04%11.21 11.21 8.88 0 N/A 0.035 #N/A #N/A N/A N/A 0.00 10.89 11.21 10.89 11.21 10.89 8.88 8.88
D4 d4
10 53.51 53.20 3.10%1.36 1.36 0.58 280 0.60% Gutter
0.012 3.61 19.18 0.19 3.16 1.48 11.61 2.83 5.00 2.83 5.00 2.06 5.00
D5 d5
10 53.51 53.20 3.10%1.27 1.27 0.47 285 0.60% Gutter
0.012 3.61 19.18 0.19 3.16 1.50 11.64 2.77 5.00 2.77 5.00 1.97 5.00
E1 e1
32 53.67 52.43 3.88%2.22 2.22 0.92 611 0.40% Gutter
0.012 3.61 19.18 0.19 2.58 3.95 13.57 6.16 6.16 6.16 6.16 4.87 5.00
F1 f1
100 51.80 49.42 2.38%12.46 12.46 11.72 290 0.50% Valley Pan
0.012 6.00 10.25 0.59 6.14 0.79 12.17 13.24 12.17 13.24 12.17 12.51 12.17
G1 g1
300 51.00 49.00 0.67%33.37 33.37 31.52 0 N/A 0.035 #N/A #N/A N/A N/A 0.00 11.67 33.37 11.67 33.37 11.67 31.52 11.67
P p 115 52.39 45.60 5.90% 9.89 9.89 9.31 290 0.50% Valley Pan 0.012 6.00 10.25 0.59 6.14 0.79 12.25 10.67 10.67 10.67 10.67 10.09 10.09
F1 FUTURE f1 future 50 51.80 49.42 4.76%1.97 1.97 0.79 340 0.50% Gutter 0.012 3.61 19.18 0.19 2.88 1.96 12.17 3.93 5.00 3.93 5.00 2.75 5.00
G1 FUTURE g1 future 100 56.60 52.17
4.43%2.85 2.85 1.14 200
0.50% Gutter 0.012 3.61 19.18 0.19 2.88 1.16 11.67 4.00 5.00 4.00 5.00 2.29 5.00
C2.1 c2.1 45 - -33.00%0.59 N/A N/A 0 N/A 0.000 #N/A #N/A N/A N/A 0.00 10.25 5.00 5.00 5.00 5.00 5.00 5.00
D1.1 d1.1 45 - -33.00%0.59 N/A N/A 0 N/A 0.000 #N/A #N/A N/A N/A 0.00 10.25 5.00 5.00 5.00 5.00 5.00 5.00
D1.2 d1.2 45 - -33.00%0.59 N/A N/A 0 N/A 0.000 #N/A #N/A N/A N/A 0.00 10.25 5.00 5.00 5.00 5.00 5.00 5.00
D1.3 d1.3 45 - -33.00%0.59 N/A N/A 0 N/A 0.000 #N/A #N/A N/A N/A 0.00 10.25 5.00 5.00 5.00 5.00 5.00 5.00
D1.4 d1.4 45 - -
33.00%0.59 N/A N/A 0
N/A 0.000 #N/A #N/A N/A N/A 0.00 10.25 5.00 5.00 5.00 5.00 5.00 5.00
FUTURE future 160 53.11 49.84 2.04%7.18 7.18 3.85 611 0.40% Gutter 0.012 3.61 19.18 0.19 2.58 3.95 14.28 11.13 11.13 11.13 11.13 7.80 7.80
WQCV wqcv 115 52.39 45.60 5.90%7.71 7.71 6.58 611 0.40% Gutter 0.012 3.61 19.18 0.19 2.58 3.95 14.03 11.65 11.65 11.65 11.65 10.53 10.53
UG1 ug1 33 53.31 52.51 2.42%1.93 1.93 0.80 295 0.50% Valley Pan 0.012 6.00 10.25 0.59 6.14 0.80 11.82 2.73 5.00 2.73 5.00 1.60 5.00
UG2 ug2 45 53.66 52.42 2.76%2.91 2.91 1.17 510 0.50% Gutter 0.012 3.61 19.18 0.19 2.88 2.95 13.08 5.85 5.85 5.85 5.85 4.12 5.00
UG3 ug3 25 52.66 51.93 2.92%1.36 1.36 0.65 225 0.50% Gutter 0.012 3.61 19.18 0.19 2.88 1.30 11.39 2.66 5.00 2.66 5.00 1.95 5.00
UG4 ug4 160 53.11 49.84
2.04%9.01 9.01 6.14 285
0.60% Gutter 0.012 3.61 19.18 0.19 3.16 1.50 12.47 10.51 10.51 10.51 10.51 7.64 7.64
UG1* ug1*33 53.31 52.51 2.42%1.95 N/A N/A 295 0.50% Valley Pan 0.012 6.00 10.25 0.59 6.14 0.80 11.82 2.75 5.00 N/A N/A N/A N/A
UG2* ug2*45 53.66 52.42 2.76%2.87 N/A N/A 510 0.50% Gutter 0.012 3.61 19.18 0.19 2.88 2.95 13.08 5.82 5.82 N/A N/A N/A N/A
UG3* ug3*25 52.66 51.93 2.92%1.26 N/A N/A 225 0.50% Gutter 0.012 3.61 19.18 0.19 2.88 1.30 11.39 2.56 5.00 N/A N/A N/A N/A
UG4* ug4*160 53.11 49.84
2.04%9.96 N/A N/A 285
0.60% Gutter 0.012 3.61 19.18 0.19 3.16 1.50 12.47 11.46 11.46 N/A N/A N/A N/A
Notes
S = Longitudinal Slope, feet/feet
R = Hydraulic Radius (feet)
n = Roughness Coefficient
V = Velocity (ft/sec) WP = Wetted Perimeter (ft)
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Location:
Maximum Tc:Overland Flow, Time of Concentration:
Channelized Flow, Velocity: Channelized Flow, Time of Concentration:
Tapestry
Fort Collins
J. Obanion
April 23, 2024
Project:
Calculations By:
Date:
Combined Basins Minor Storm Event
Combined Basins
Basin ID Design
Point
Overland Flow Channelized Flow Time of Concentration
Future Development Basins
Minor Storm Event Sub-Basins
Proposed Basins
(Equation 3.3-2 per Fort Collins Stormwater Manual)𝑇 =1.87 1.1−𝐶∗𝐶𝑓𝐿
𝑆ଵ ଷൗ
𝑉=1.49
𝑛∗𝑅ଶ/ଷ ∗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.
3) Assume a water depth of 6" and a typical curb and gutter per Larimer
County Urban Street Standard Detail 701 for curb and gutter channelized
flow. Assume a water depth of 1', fixed side slopes, and a triangular
swale section for grass channelized flow. Assume a water depth of 1', 4:1
side slopes, and a 2' wide valley pan for channelized flow in a valley pan.
Page 1 of 1
Tc2 Tc10 Tc100 C2 C10 C100 I2 I10 I100 Q2 Q10 Q100
A1 a1 0.50 5.0 5.0 5.0 0.8 0.8 0.9 2.9 4.9 10.0 1.1 1.8 4.7
A2 a2 0.33 5.0 5.0 5.0 0.8 0.8 1.0 2.9 4.9 10.0 0.8 1.3 3.3
B1 b1 0.66 5.0 5.0 5.0 0.8 0.8 1.0 2.9 4.9 10.0 1.6 2.6 6.6
B2 b2 0.97 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 2.5 4.2 9.7
C1 c1 1.29 5.5 5.5 5.0 0.7 0.7 0.9 2.8 4.7 10.0 2.6 4.5 11.8
C2 c2 0.61 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 1.5 2.5 6.0
D1 d1 0.73 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 1.8 3.2 7.2
D2 d2 0.23 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 0.6 1.0 2.3
D3 d3 1.11 10.9 10.9 8.9 0.5 0.5 0.6 2.2 3.7 8.2 1.2 2.1 5.7
D4 d4 0.21 5.0 5.0 5.0 0.8 0.8 1.0 2.9 4.9 10.0 0.4 0.8 2.0
D5 d5 0.21 5.0 5.0 5.0 0.8 0.8 1.0 2.9 4.9 10.0 0.5 0.8 2.0
E1 e1 1.24 6.2 6.2 5.0 0.8 0.8 1.0 2.7 4.6 10.0 2.5 4.4 11.9
F1 f1 1.15 12.2 12.2 12.2 0.2 0.2 0.3 2.1 3.5 7.2 0.5 0.8 2.2
G1 g1 1.26 11.7 11.7 11.7 0.2 0.2 0.3 2.1 3.6 7.3 0.5 0.9 2.3
P p 1.49 10.7 10.7 10.1 0.2 0.2 0.3 2.2 3.7 7.7 0.7 1.2 3.0
F1 FUTURE f1 future 1.15 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 2.8 4.8 11.5
G1 FUTURE g1 future 1.26 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 3.0 5.2 12.5
C2.1 c2.1 0.04 5.0 5.0 5.0 1.0 n/a n/a 2.9 N/A N/A 0.1 n/a n/a
D1.1 d1.1 0.01 5.0 5.0 5.0 1.0 n/a n/a 2.9 N/A N/A 0.0 n/a n/a
D1.2 d1.2 0.04 5.0 5.0 5.0 1.0 n/a n/a 2.9 N/A N/A 0.1 n/a n/a
D1.3 d1.3 0.16 5.0 5.0 5.0 1.0 n/a n/a 2.9 N/A N/A 0.4 n/a n/a
D1.4 d1.4 0.07 5.0 5.0 5.0 1.0 n/a n/a 2.9 N/A N/A 0.2 n/a n/a
FUTURE future 11.98 11.1 11.1 7.8 0.7 0.7 0.9 2.1 3.6 8.6 18.2 31.1 91.9
WQCV wqcv 5.97 11.7 11.7 10.5 0.4 0.4 0.5 2.1 3.6 7.6 5.1 8.6 22.9
UG1 ug1 1.64 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 4.0 6.8 16.3
UG2 ug2 1.89 5.9 5.9 5.0 0.8 0.8 1.0 2.8 4.7 10.0 4.1 6.9 18.3
UG3 ug3 0.73 5.0 5.0 5.0 0.9 0.9 1.0 2.9 4.9 10.0 1.8 3.2 7.2
UG4 ug4 1.75 10.5 10.5 7.6 0.6 0.6 0.8 2.2 3.7 8.6 2.3 4.0 11.6
UG1* ug1* 1.59 5.0 N/A N/A 0.9 n/a n/a 2.9 N/A N/A 3.9 n/a n/a
UG2* ug2* 1.94 5.8 N/A N/A 0.8 n/a n/a 2.8 N/A N/A 4.2 n/a n/a
UG3* ug3* 0.97 5.0 N/A N/A 0.9 n/a n/a 2.9 N/A N/A 2.5 n/a n/a
UG4*ug4*1.52 11.5 N/A N/A
0.57 n/a n/a 2.1 N/A N/A
1.83 n/a n/a
Proposed Basins
Minor Storm Event Sub-Basins
Date:
Fort Collins
Project:
Location:
Calc. By:
Combined Basins Minor Storm Event
DEVELOPED DIRECT RUNOFF COMPUTATIONS
Intensity Flow (cfs)
Tapestry
J. Obanion
April 23, 2024
Basin Design
Point
Intensity, I, from Fig. 3.4.1 Fort Collins Stormwater Manual.
Rational Equation: Q = CiA (Equation 6-1 per MHFD)
Area
(acres)
Runoff CTc (Min)
Combined Basins
Future Development Basins
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APPENDIX B
HYDRAULIC CALCULATIONS
Pond No :
P
100-yr
0.89
9.20 min 124002 ft3
11.98 acres 2.847 ac-ft
Max Release Rate =2.40 cfs
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 31827 1.00 2.40 719 31108
10 7.720 49387 1.00 2.40 1438 47950
15 6.520 62566 1.00 2.40 2156 60409
20 5.600 71650 1.00 2.40 2875 68775
25 4.980 79647 1.00 2.40 3594 76053
30 4.520 86748 1.00 2.40 4313 82435
35 4.080 91354 1.00 2.40 5032 86322
40 3.740 95704 1.00 2.40 5750 89954
45 3.460 99606 1.00 2.40 6469 93137
50 3.230 103317 1.00 2.40 7188 96129
55 3.030 106611 1.00 2.40 7907 98705
60 2.860 109778 1.00 2.40 8626 101152
65 2.720 113105 1.00 2.40 9344 103760
70 2.590 115983 1.00 2.40 10063 105920
75 2.480 118990 1.00 2.40 10782 108208
80 2.380 121805 1.00 2.40 11501 110304
85 2.290 124524 1.00 2.40 12220 112304
90 2.210 127243 1.00 2.40 12938 114304
95 2.130 129450 1.00 2.40 13657 115793
100 2.060 131785 1.00 2.40 14376 117409
105 2.000 134344 1.00 2.40 15095 119249
110 1.940 136519 1.00 2.40 15814 120705
115 1.890 139046 1.00 2.40 16532 122513
120 1.840 141253 1.00 2.40 17251 124002
*Note: Using the method described in FCSCM Chapter 6 Section 2.3
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Input Variables Results
Required Detention Volume
Fort Collins, Colorado
473-010 - Conceptual
Tapestry
Project Number :
Project Name :
Detention Pond
A =
Tc =
Project Location :
Design Point
C =
Design Storm
Page 1 of 1
473-010_FAAModified Method
Pond Stage-Storage Curve
Proposed Detention Pond
437-010 Tapestry
By: J. Obanion
4/18/2024
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
4,944.200 287.30 0.00 0.00
4,944.400 1,255.10 154.24 0.00
4,944.600 2,805.77 560.33 0.01
4,944.800 5,442.80 1385.18 0.03
4,945.000 8,527.89 2782.25 0.06
4,945.15 17,200.40 4330.00 0.10 WQV
4,945.200 12,178.27 4852.87 0.11
4,945.400 15,545.77 7625.27 0.18
4,945.600 18,869.08 11066.76 0.25
4,945.800 21,161.65 15069.83 0.35
4,946.000 22,924.85 19478.48 0.45
4,946.200 24,375.10 24208.48 0.56
4,946.400 25,576.80 29203.67 0.67
4,946.600 26,527.49 34414.09 0.79
4,946.800 27,433.93 39810.24 0.91
4,947.000 28,347.20 45388.35 1.04
4,947.200 29,267.29 51149.80 1.17
4,947.400 30,194.09 57095.94 1.31
4,947.600 31,127.72 63228.12 1.45
4,947.800 32,069.49 69547.84 1.60
4,948.000 33,019.80 76056.77 1.75
4,948.200 33,978.63 82756.61 1.90
4,948.400 34,945.98 89649.07 2.06
4,948.600 35,955.88 96739.26 2.22
4,948.800 37,088.20 104043.67 2.39
4,949.000 38,326.16 111585.10 2.56
4,949.200 39,667.93 119384.51 2.74
4,949.400 41,112.18 127462.52 2.93
4,949.44 41,297.36 128332.00 2.95 100-YR DETENTION
4,949.500 41,873.49 131611.80 3.02
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APPENDIX C
WATER QUALITY/LID COMPUTATIONS
Project Title Date:
Project Number Calcs By:
City
Basins
Facility ID
1
WQCV = Watershed inches of Runoff (inches)35%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.166 in
5.98 ac
0.0828 ac-ft 3609 cu. ft.
0.0994 ac-ft 4330 cu. ft.
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
V =
V (120%) =
A =
Tapestry April 23, 2024
473-010 J. Obanion
Fort Collins
A1, A2, E1,F1,G1,P
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Detention Pond WQCV
0.212
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
1
0.
2
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1
WQ
C
V
(
w
a
t
e
r
s
h
e
d
i
n
c
h
e
s
)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
iii78.019.10.91aWQCV 23
iii78.019.10.91aWQCV 23
AV*12
WQCV
40 hr
Project Title Date:
Project Number Calcs By:
City
Basins
Facility ID
0.8
WQCV = Watershed inches of Runoff (inches)84%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.303 in
1.64 ac
0.0414 ac-ft 1803 cu-ft
0.0497 ac-ft 2164 cu-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
V =
V (120%) =
A =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Tapestry April 23, 2024
473-010 J. Obanion
Fort Collins
B1 & B2
Drain Time
a =
i =
WQCV =
Underground Chamber 1
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
1
0.
2
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1
WQ
C
V
(
w
a
t
e
r
s
h
e
d
i
n
c
h
e
s
)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
iii78.019.10.91aWQCV 23
AV*12
WQCV
12 hrWQCV=(a 0.91𝑖ଷ − 1.19𝑖
ଶ + 0.78𝑖)1.067
Page 1 of 8
473-010 Stormtech Chambers
Facility ID :
B1
WQ
0.86
5.00 min 840 ft3
1.64 acres 0.02 ac-ft
Max Release Rate =0.45 cfs
Time (min)Fort Collins WQ
Intensity (in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
QWQ
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 603 1.00 0.45 135 468
10 1.105 935 1.00 0.45 270 665
15 0.935 1187 1.00 0.45 405 782
20 0.805 1362 1.00 0.45 540 822
25 0.715 1513 1.00 0.45 675 838
30 0.650 1650 1.00 0.45 810 840
35 0.585 1733 1.00 0.45 945 788
40 0.535 1811 1.00 0.45 1080 731
45 0.495 1885 1.00 0.45 1215 670
50 0.460 1946 1.00 0.45 1350 596
55 0.435 2025 1.00 0.45 1485 540
60 0.410 2082 1.00 0.45 1620 462
65 0.385 2118 1.00 0.45 1755 363
70 0.365 2162 1.00 0.45 1890 272
75 0.345 2190 1.00 0.45 2025 165
80 0.330 2234 1.00 0.45 2160 74
85 0.315 2266 1.00 0.45 2295 -29
90 0.305 2323 1.00 0.45 2430 -107
95 0.290 2331 1.00 0.45 2565 -234
100 0.280 2369 1.00 0.45 2700 -331
105 0.270 2399 1.00 0.45 2835 -436
110 0.260 2420 1.00 0.45 2970 -550
115 0.255 2482 1.00 0.45 3105 -623
120 0.245 2488 1.00 0.45 3240 -752
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Input Variables Results
`
Fort Collins, CO
473-010
Tapestry
Project Number :
Project Name :
Underground Chamber 1
A =
Tc =
Project Location :
Design Point
C =
Design Storm
Page 2 of 8
473-010 Stormtech Chambers
Project Title Date:
Project Number Calcs By:
City
Basins
Facility ID
0.8
WQCV = Watershed inches of Runoff (inches)75%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.256 in
1.94 ac
0.0413 ac-ft 1801 cu-ft
0.0496 ac-ft 2161 cu-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
A =
V =
V (120%) =
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Tapestry April 23, 2024
473-010 J. Obanion
Fort Collins
C1, C2, C2.1
Underground Chamber 2
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
1
0.
2
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1
WQ
C
V
(
w
a
t
e
r
s
h
e
d
i
n
c
h
e
s
)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
iii78.019.10.91aWQCV 23
AV*12
WQCV
12 hrWQCV=(a 0.91𝑖ଷ − 1.19𝑖
ଶ + 0.78𝑖)1.067
Page 3 of 8
473-010 Stormtech Chambers
Facility ID :
C2
WQ
0.78
5.00 min 906 ft3
1.94 acres 0.02 ac-ft
Max Release Rate =0.48 cfs
Time (min)Fort Collins WQ
Intensity (in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
QWQ
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 647 1.00 0.48 144 503
10 1.105 1003 1.00 0.48 288 715
15 0.935 1273 1.00 0.48 432 841
20 0.805 1462 1.00 0.48 576 886
25 0.715 1623 1.00 0.48 720 903
30 0.650 1770 1.00 0.48 864 906
35 0.585 1859 1.00 0.48 1008 851
40 0.535 1943 1.00 0.48 1152 791
45 0.495 2022 1.00 0.48 1296 726
50 0.460 2088 1.00 0.48 1440 648
55 0.435 2172 1.00 0.48 1584 588
60 0.410 2233 1.00 0.48 1728 505
65 0.385 2272 1.00 0.48 1872 400
70 0.365 2320 1.00 0.48 2016 304
75 0.345 2349 1.00 0.48 2160 189
80 0.330 2397 1.00 0.48 2304 93
85 0.315 2431 1.00 0.48 2448 -17
90 0.305 2492 1.00 0.48 2592 -100
95 0.290 2501 1.00 0.48 2736 -235
100 0.280 2542 1.00 0.48 2880 -338
105 0.270 2574 1.00 0.48 3024 -450
110 0.260 2597 1.00 0.48 3168 -571
115 0.255 2662 1.00 0.48 3312 -650
120 0.245 2669 1.00 0.48 3456 -787
C =
Tc =
A =
Underground Chamber 2
Input Variables Results
Design Point
Design Storm `
Project Location : Fort Collins, CO
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Project Number : 473-010
Project Name : Tapestry
Page 4 of 8
473-010 Stormtech Chambers
Project Title Date:
Project Number Calcs By:
City
Basins
Facility ID
0.8
WQCV = Watershed inches of Runoff (inches)90%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.343 in
0.97 ac
0.0277 ac-ft 1207 cu-ft
0.0332 ac-ft 1448 cu-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
A =
V =
V (120%) =
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Tapestry April 23, 2024
473-010 J. Obanion
Fort Collins
D1, D1.1, D1.3, D1.4
Underground Chamber 3
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
1
0.
2
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1
WQ
C
V
(
w
a
t
e
r
s
h
e
d
i
n
c
h
e
s
)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
iii78.019.10.91aWQCV 23
AV*12
WQCV
12 hrWQCV=(a 0.91𝑖ଷ − 1.19𝑖
ଶ + 0.78𝑖)1.067
Page 5 of 8
473-010 Stormtech Chambers
Facility ID :
D1
WQ
0.91
5.00 min 529 ft3
0.97 acres 0.01 ac-ft
Max Release Rate =0.28 cfs
Time (min)Fort Collins WQ
Intensity (in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
QWQ
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 377 1.00 0.28 84 293
10 1.105 585 1.00 0.28 168 417
15 0.935 743 1.00 0.28 252 491
20 0.805 853 1.00 0.28 336 517
25 0.715 947 1.00 0.28 420 527
30 0.650 1033 1.00 0.28 504 529
35 0.585 1084 1.00 0.28 588 496
40 0.535 1133 1.00 0.28 672 461
45 0.495 1180 1.00 0.28 756 424
50 0.460 1218 1.00 0.28 840 378
55 0.435 1267 1.00 0.28 924 343
60 0.410 1303 1.00 0.28 1008 295
65 0.385 1325 1.00 0.28 1092 233
70 0.365 1353 1.00 0.28 1176 177
75 0.345 1370 1.00 0.28 1260 110
80 0.330 1398 1.00 0.28 1344 54
85 0.315 1418 1.00 0.28 1428 -10
90 0.305 1454 1.00 0.28 1512 -58
95 0.290 1459 1.00 0.28 1596 -137
100 0.280 1483 1.00 0.28 1680 -197
105 0.270 1501 1.00 0.28 1764 -263
110 0.260 1515 1.00 0.28 1848 -333
115 0.255 1553 1.00 0.28 1932 -379
120 0.245 1557 1.00 0.28 2016 -459
C =
Tc =
A =
Underground Chamber 3
Input Variables Results
Design Point
Design Storm `
Project Location : Fort Collins, CO
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Project Number : 473-010
Project Name : Tapestry
Page 6 of 8
473-010 Stormtech Chambers
Project Title Date:
Project Number Calcs By:
City
Basins
Facility ID
0.8
WQCV = Watershed inches of Runoff (inches)54%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.186 in
1.75 ac
0.0271 ac-ft 1179 cu-ft
0.0325 ac-ft 1415 cu-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Tapestry April 23, 2024
473-010 J. Obanion
Fort Collins
D2, D3, D4, D5
Underground Chamber 4
A =
V =
V (120%) =
Drain Time
a =
i =
WQCV =
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
1
0.
2
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1
WQ
C
V
(
w
a
t
e
r
s
h
e
d
i
n
c
h
e
s
)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
iii78.019.10.91aWQCV 23
AV*12
WQCV
12 hrWQCV=(a 0.91𝑖ଷ − 1.19𝑖
ଶ + 0.78𝑖)1.067
Page 7 of 8
473-010 Stormtech Chambers
Facility ID :
D1
WQ
0.62
9.92 min 657 ft3
1.75 acres 0.02 ac-ft
Max Release Rate =0.34 cfs
Time (min)Fort Collins WQ
Intensity (in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
QWQ
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 464 1.00 0.34 102 362
10 1.105 719 1.00 0.34 204 515
15 0.935 913 1.00 0.34 306 607
20 0.805 1048 1.00 0.34 408 640
25 0.715 1164 1.00 0.34 510 654
30 0.650 1269 1.00 0.34 612 657
35 0.585 1333 1.00 0.34 714 619
40 0.535 1393 1.00 0.34 816 577
45 0.495 1450 1.00 0.34 918 532
50 0.460 1497 1.00 0.34 1020 477
55 0.435 1558 1.00 0.34 1122 436
60 0.410 1601 1.00 0.34 1224 377
65 0.385 1629 1.00 0.34 1326 303
70 0.365 1663 1.00 0.34 1428 235
75 0.345 1684 1.00 0.34 1530 154
80 0.330 1719 1.00 0.34 1632 87
85 0.315 1743 1.00 0.34 1734 9
90 0.305 1787 1.00 0.34 1836 -49
95 0.290 1794 1.00 0.34 1938 -144
100 0.280 1823 1.00 0.34 2040 -217
105 0.270 1846 1.00 0.34 2142 -296
110 0.260 1862 1.00 0.34 2244 -382
115 0.255 1909 1.00 0.34 2346 -437
120 0.245 1914 1.00 0.34 2448 -534
Project Location : Fort Collins, CO
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Project Number : 473-010
Project Name : Tapestry
C =
Tc =
A =
Underground Chamber 4
Input Variables Results
Design Point
Design Storm `
Page 8 of 8
473-010 Stormtech Chambers
Vault ID
Total
Required
WQ Volume
(cf)
Flow,
WQ
(cfs)
Chamber
Type
Chamber Release
Ratea
(cfs)
Chamber
Volumeb
(cf)
Installed
Chamber w/
Aggregatec
(cf)
Minimum No.
of Chambersd
Total Release
Ratee
(cfs)
Required
Storage
Volume by
FAA Method
(cf)
Minimum No.
of Chambersf
Provided
Number of
Chambers
Provided
Release Rate
(cfs)
Storage
Provided
within the
Chambersg
(cf)
Total
Installed
System WQ
Volumeh
(cf)
Chamber 1 2164 0.00 SC-740 0.024 45.90 67.65 32 0.45 840 19 32 0.75 1469 2165
Chamber 2 2161 0.00 SC-740 0.024 45.90 67.65 32 0.47 906 20 32 0.75 1469 2165
Chamber 3 1448 0.00 SC-740 0.024 45.90 67.65 22 0.28 529 12 22 0.52 1010 1488
Chamber 4 1415 0.00 SC-740 0.024 45.90 67.65 21 0.35 657 15 21 0.50 964 1421
a. Release rate per chamber, limited by flow through geotextile with accumulated sediment.
b. Volume within chamber only, not accounting for void spaces in surrounding aggregate.
c. Volume includes chamber and void spaces (30%) in surrounding aggregate, per chamber unit.
d. Number of chambers required to provide full WQCV within total installed system, including aggregate.
e. Release rate per chamber times number of chambers.
f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).
g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.
h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.
Chamber Configuration Summary
Page 1 of 1
473-010 Stormtech Chambers
Flow Rate* 0.35 gpm/sf
1 cf =7.48052 gal
1 gallon =0.133680546 cf
1 GPM = 0.002228009 cfs
*Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Report
Width (in)Length (in)Height (in)Floor Area (sf)Chamber Volume (cf)Chamber/Aggregate Volume (cf)Chamber Flow Rate
SC-160 34.0 85.4 16.0 20.2 6.9 23.7 0.015723865
SC-310 34.0 85.4 16.0 20.2 14.7 25.7 0.015723865
SC-740 51.0 85.4 30.0 30.2 45.9 67.7 0.023585797
MC-3500 77.0 90.0 45.0 48.1 109.9 158.7 0.037528028
MC-4500 100.0 52.0 60.0 36.1 106.5 148.6 0.028158693
Chamber Dimensions
Chamber Flow Rate Conversion (gpm/sf to cfs)
Page 1 of 1
473-010 Stormtech Chambers
Project Number:Project:Tapestry
Project Location:
Calculations By:Date:4/23/2024
Sq. Ft. Acres
A1 21,615 0.50 72%n/a Traditional 15,472
A2 14,521 0.33 80%n/a Traditional 11,649
B1 28,844 0.66 80%Underground Chambers 1 Underground Detention 23,104
B2 42,425 0.97 88%Underground Chambers 1 Underground Detention 37,152
C1 56,052 1.29 69%Underground Chambers 2 Underground Detention 38,950
C2 26,477 0.61 85%Underground Chambers 2 Underground Detention 22,477
D1 31,612 0.73 89%Underground Chambers 3 Underground Detention 28,274
D2 10,089 0.23 90%Underground Chambers 4 Underground Detention 9,092
D3 48,426 1.11 38%Underground Chambers 4 Underground Detention 18,536
D4 8,968 0.21 76%Underground Chambers 4 Underground Detention 6,808
D5 8,933 0.21 79%Underground Chambers 4 Underground Detention 7,032
E1 53,951 1.24 74%n/a Traditional 31,777
F1 50,150 1.15 3%n/a Traditional 1,699
G1 54,755 1.26 2%n/a Traditional 1,095
P 64,852 1.49 3%n/a Traditional 2,048
Total 521,669 11.98 255,163
Sq. Ft. Acres
Underground Chambers 1 71,269 1.64 85% 60,257
B1 & B2 Underground Detention
Underground Chambers 2 82,529 1.89 74% 61,427
C1 & C2 Underground Detention
Underground Chambers 3 31,612 0.73 89% 28,274
D1 Underground Detention
Underground Chambers 4 76,415 1.75 54% 41,467
D2, D3, D4, & D5 Underground Detention
Total 261,825 6.01 191,425
521,669 ft2
255,163 ft2
191,373 ft2
191,425 ft2
75.02%Percent Impervious Treated by LID
473-010
Fort Collins, Colorado
J. Obanion
Total New or Modified
Impervious Area (ft2)
Total Impervious Area Treated by LID
75% Required Minimum Area to be Treated by LID
Total Area of Current Development
Total New or Modified Impervious Area
LID Site Summary - New Impervious Area
LID ID
LID Summary per Basin
LID Summary
Tributary Area Weighted %
Impervious Subbasin ID Treatment TypeWQ Treatment Impervious Area (ft2)
Water Quality Treatment via LID
AreaBasin ID Percent
Impervious WQ Treatment Type
D
EE
D
E
VAULTCABLE
D
XX
AC
ACACAC
ACAC
D
D
D
X
/ / / / / / / // / / / / / / // / / / / / / // / / / / / / /
/ / / / / / / // / / / / / / // / / / / / / // / / / / / / /
DN
DN
DNDN
DN
DN
DNDN
DN DN
DN
DN
DNDN
D
EE
D
E
BUCKINGHAM STREET
3R
D
S
T
R
E
E
T
LOGAN STREET
DETENTION
POND
LOGAN STREET
A1
D4
B1 B2
C1
C2
D1
D2
D5
E1
F1
G1
P
D3
A2
D1.2
C2.1
D1.1
D1.3
D1.4
A1
A2
B1 B2
C1
C2
D1 D2
D3 D5
E1
F1
G1
P
C2.1
UNDERGROUND
CHAMBERS 2
UNDERGROUND
CHAMBERS 1
UNDERGROUND
CHAMBERS 3
UNDERGROUND
CHAMBERS 4
D4
DRAWN BY:
SCALE:
ISSUED:
TAPESTRY
SHEET NO:
FORT COLLINS: 301 North Howes Street, Suite 100, 80521
GREELEY: 820 8th Street, 80631
E N G I N E E R N GI
EHTRON R N
970.221.4158
northernengineering.com
LID EXHIBIT
J. OBanion
1in=120ft
04/24/2024
PROPOSED STORM SEWER
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
aDESIGN POINT
DRAINAGE BASIN LABEL
MAJOR EVENT DRAINAGE BASIN BOUNDARY
A
LEGEND:
( IN FEET )
1 inch = ft.
Feet0120120
120
AREA TREATED BY UNDERGROUND CHAMBERS 1
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
AREA TREATED BY UNDERGROUND CHAMBERS 2
AREA TREATED BY UNDERGROUND CHAMBERS 3
*SEE RATIONAL CALCS FOR IMPERVIOUS AREA CALCULATIONS
AREA TREATED BY UNDERGROUND CHAMBERS 4
MINOR EVENT DRAINAGE BASIN BOUNDARY
LID Site Summary - New Impervious Area
Total Area of Current Development 521,669 ft2
Total New or Modified Impervious Area 255,163 ft2
75% Required Minimum Area to be Treated by LID 191,373 ft2
Total Impervious Area Treated by LID 191,425 ft2
Percent Impervious Treated by LID 75.02%
EPSGROUPINC.COM | NORTHERNENGINEERING.COM | 970.221.4158
Fort Collins | Greeley | Mesa | Tucson | Goodyear | Phoenix | Fort Worth
APPENDIX D
EROSION CONTROL REPORT
EPSGROUPINC.COM | NORTHERNENGINEERING.COM | 970.221.4158
Fort Collins | Greeley | Mesa | Tucson | Goodyear | Phoenix | Fort Worth
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.
EPSGROUPINC.COM | NORTHERNENGINEERING.COM | 970.221.4158
Fort Collins | Greeley | Mesa | Tucson | Goodyear | Phoenix | Fort Worth
APPENDIX E
USDA SOILS REPORT
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 29, 2024
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
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
Larimer County Area, Colorado......................................................................13
22—Caruso clay loam, 0 to 1 percent slope...............................................13
64—Loveland clay loam, 0 to 1 percent slopes...........................................14
References............................................................................................................16
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
Custom Soil Resource Report
6
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8
9
Custom Soil Resource Report
Soil Map
44
9
3
2
5
0
44
9
3
2
9
0
44
9
3
3
3
0
44
9
3
3
7
0
44
9
3
4
1
0
44
9
3
4
5
0
44
9
3
4
9
0
44
9
3
5
3
0
44
9
3
2
5
0
44
9
3
2
9
0
44
9
3
3
3
0
44
9
3
3
7
0
44
9
3
4
1
0
44
9
3
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5
0
44
9
3
4
9
0
44
9
3
5
3
0
494510 494550 494590 494630 494670 494710
494510 494550 494590 494630 494670 494710
40° 35' 33'' N
10
5
°
3
'
5
4
'
'
W
40° 35' 33'' N
10
5
°
3
'
4
4
'
'
W
40° 35' 23'' N
10
5
°
3
'
5
4
'
'
W
40° 35' 23'' N
10
5
°
3
'
4
4
'
'
W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,570 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 18, Aug 24, 2023
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug 25,
2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
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
2.1 15.9%
64 Loveland clay loam, 0 to 1
percent slopes
11.1 84.1%
Totals for Area of Interest 13.3 100.0%
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,
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:Occasional
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
64—Loveland clay loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpx9
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
Loveland and similar soils:90 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Loveland
Setting
Landform:Flood plains, stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 15 inches: clay loam
H2 - 15 to 32 inches: loam
H3 - 32 to 60 inches: very gravelly sand
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Poorly drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20
to 0.60 in/hr)
Depth to water table:About 18 to 36 inches
Frequency of flooding:Occasional
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Very slightly saline to slightly saline (2.0 to 4.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 7.5 inches)
Custom Soil Resource Report
14
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: C
Ecological site: R067BY036CO - Overflow
Hydric soil rating: No
Minor Components
Aquolls
Percent of map unit:5 percent
Landform:Swales
Hydric soil rating: Yes
Poudre
Percent of map unit:5 percent
Ecological site:R067BY036CO - Overflow
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
EPSGROUPINC.COM | NORTHERNENGINEERING.COM | 970.221.4158
Fort Collins | Greeley | Mesa | Tucson | Goodyear | Phoenix | Fort Worth
MAP PACKET
DR1 – HISTORIC DRAINAGE EXHIBIT
DR2 – DEVELOPED DRAINAGE EXHIBIT
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NEW BELGIUM BREWING CO INC
902 BUCKINGHAM STREET
ALFREDO LOZANO
128 3RD STREET
G AND A INVESTMENTS LLC
903 BUCKINGHAM STREET
20' DRAINAGE EASEMENT
BY SEPARATE DOCUMENT
REC. NO. ______________
/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /
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D1.3
D1.4
TIE INTO EXISTING MANHOLE
EX. STORM MANHOLE
RIM: 4947.73
INV IN (NE): 4943.26 15" PVC
INV OUT: 4943.21 15" PVC
EXISTING
STORM INLET
EXISTING STORM
MANHOLE
EXISTING
STORM INLET
TEMPORARY CONSTRUCTION
EASEMENT
REC. NO. 20090031970
PRIVATE ACCESS & UTILITY
EASEMENT
REC. NO. 20100026776
PROPOSED INLET
PROPOSED
INLET
PROPOSED
INLET
PROPOSED INLET
COMBINED
INLET
AND WEIR
STRUCTURE
PROPOSED INLET
PROPOSED INLET
PROPOSED INLET
WEIR
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PROPOSED OUTLET
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PROPOSED INLET
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LOT 1
ODELL INVESTMENTS LLC
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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
NORTH
( IN FEET )
1 inch = ft.
Feet05050
50
100 150
NORTH
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
MAJOR EVENT DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION
11
NOTES:
1.REFER TO THE PRELIMINARY DRAINAGE REPORT FOR TAPESTRY, DATED APRIL 17,
2024 FOR ADDITIONAL INFORMATION.
A
LEGEND:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
MINOR EVENT DRAINAGE BASIN BOUNDARY
DEVELOPED DRAINAGE SUMMARY
Basin ID Design
Point
Total Area
(acres)C2 C100 2-Yr Tc
(min)
100-Yr Tc
(min)
Q2
(cfs)
Q100
(cfs)
Proposed Basins
A1 a1 0.50 0.76 0.95 5.00 5.00 1.07 4.67
A2 a2 0.33 0.80 1.00 5.00 5.00 0.76 3.31
B1 b1 0.66 0.82 1.00 5.00 5.00 1.55 6.59
B2 b2 0.97 0.88 1.00 5.00 5.00 2.46 9.69
C1 c1 1.29 0.74 0.92 5.53 5.00 2.61 11.77
C2 c2 0.61 0.86 1.00 5.00 5.00 1.49 6.05
D1 d1 0.73 0.89 1.00 5.00 5.00 1.85 7.22
D2 d2 0.23 0.90 1.00 5.00 5.00 0.59 2.30
D3 d3 1.11 0.50 0.62 10.89 8.88 1.20 5.69
D4 d4 0.21 0.77 0.96 5.00 5.00 0.45 1.96
D5 d5 0.21 0.79 0.98 5.00 5.00 0.46 2.01
E1 e1 1.24 0.77 0.96 6.16 5.00 2.55 11.87
F1 f1 1.15 0.21 0.26 12.17 12.17 0.50 2.17
G1 g1 1.26 0.20 0.25 11.67 11.67 0.53 2.29
P p 1.49 0.21 0.26 10.67 10.09 0.67 3.00
Future Development Basins
F1 FUTURE f1 future 1.15 0.85 1.00 5.00 5.00 2.79 11.46
G1 FUTURE g1 future 1.26 0.85 1.00 5.00 5.00 3.05 12.51
Minor Storm Event Sub-Basins
C2.1 c2.1 0.04 0.95 n/a 5.00 5.00 0.11 n/a
D1.1 d1.1 0.01 0.95 n/a 5.00 5.00 0.04 n/a
D1.2 d1.2 0.04 0.95 n/a 5.00 5.00 0.10 n/a
D1.3 d1.3 0.16 0.95 n/a 5.00 5.00 0.43 n/a
Combined Basins
FUTURE future 11.98 0.71 0.89 11.13 7.80 18.23 91.89
WQCV wqcv 5.97 0.41 0.51 11.65 10.53 5.06 22.89
UG1 ug1 1.64 0.86 1.00 5.00 5.00 4.01 16.28
UG2 ug2 1.89 0.78 0.97 5.85 5.00 4.05 18.26
UG3 ug3 0.73 0.89 1.00 5.00 5.00 1.85 7.22
UG4 ug4 1.75 0.62 0.77 10.51 7.64 2.35 11.61
Combined Basins Minor Storm Event
UG1*ug1*1.59 0.86 n/a 5.00 N/A 3.87 n/a
UG2*ug2*1.94 0.78 n/a 5.82 N/A 4.16 n/a
UG3*ug3*0.97 0.91 n/a 5.00 N/A 2.50 n/a
UG4*ug4*1.52 0.57 n/a 11.46 N/A 1.83 n/a
POND SUMMARY TABLE
Pond ID Tributary
Area (ac)
Avg. Percent
Imperviousness
(%)
Extended
Detention
WQCV (ac-ft)
100-Yr
Detention
Vol. (ac-ft)
100-Yr
Detention
WSEL (ft)
Peak
Release
(cfs)
Detention Pond 11.98 66 0.10 2.95 4,949.44 2.40