HomeMy WebLinkAboutDrainage Reports - 07/27/2023City of Fort Collins Approved Plans
Approved by: Wes Lamarque
Date: 7/27/2023
Drainage Design Considerations
for the
Timberline - International
Final Development Plan (FDP)
Fort Collins, Colorado
June 29, 2023
Prepared for:
Owner/Developer
Mr. Devin Ferrey
FR Holdings, Ltd.
125 S. Howes Street, 2n� Floor
Fort Collins, Colorado 80521
Prepared by:
Wohnrade
Civil Engineers
11582 Co(ony Row
Broomfield, CO 80021
Phone: (720)259-0965, Fax: (720)259-1519
Project Number: 1805.00-TIM
Wo h n rad e
Civil Engineers
June 29, 2023
Mr. Wes Lamarque
Stormwater Engineering
City of Fort Collins
700 Wood Street
Fort Collins, Colorado 80522
Subject: Drainage Design Considerations for the
Timberline-International Final Development Plan (FDP)
Fort Collins, Colorado
Dear Mr. Lamarque:
Wohnrade Civil Engineers, Inc. (WCE) is pleased to resubmit this final hydrologic and
hydraulic report for the subject project for your review. We have addressed staff
comments contained in the document, Timberline-International, PDP200014, Round
Number 3, dated May 21, 2021. This report complies with technical criteria set forth in
the City of Fort Collins, Stormwater Criteria Manual, and Mile High Flood District criteria.
We acknowledge that the City of Fort Collins's review of this study is only for general
conformance with submittal requirements, current design criteria, and standard
engineering principles and practices.
If you should have any questions or comments as you review this report, please feel free to
contact me at your convenience.
Sincerely,
WOHNRADE CIVIL ENGINEERS, INC.
�l . 1/�J
Mary B. Wohnrade, P.E. - Principai
Professional Engineer - (co)
Drainage Design Considerations for
Timberline-International FDP
Table of Contents
�_„
1.1
1.2
1.3
,�
2.1
2.1
�a
3.1
3.2
4.1
4.2
4.3
4.4
��
5.1
5.2
��� ,
6.1
6.2
6.3
fi�c�"�������'���,i� �,,. �
Objective..........................................................................................................................................1
Project History and Previous Studies ...............................................................................................1
Mappingand Surveying ...................................................................................................................1
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SiteLocation .....................................................................................................................................1
SiteDescription ................................................................................................................................2
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Pre-Project Drainage Basins .............................................................................................................2
Pre-Project Drainage Patterns ......................................................................................................... 2
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Proposed Project Description .......................................................................................................... 3
Post-Project Drainage Basins ...........................................................................................................4
Post-Project Drainage Patterns ........................................................................................................4
ProposedDetention Pond ................................................................................................................4
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DesignReferences ............................................................................................................................6
HydrologicCriteria ........................................................................................................................... 6
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LowImpact Design (LID) ..................................................................................................................7
ErosionControl Plan ........................................................................................................................ 7
SiteStabilization ...............................................................................................................................8
�. C. r�??��;��'� �_�������'� .. . .. ��
7.1 Compliance with Standards .............................................................................................................8
7.2 Variances ..........................................................................................................................................8
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Drainage Design Considerations for
Timberline-International FDP
TABLE OF CONTENTS, cont.
Vicinity Map
APPENDICES
Appendix A: Post-Project Condition Hydrology
Appendix B: Detention Pond Design
Appendix C: LID Design
Appendix D: Future Off-site Storm Sewer Preliminary Design
DRAWINGS
Sheet 1 of 1 Post-Project Drainage Plan
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Drainage Design Considerations for
Timberline-International FDP
Fort Collins, Colorado
June 29, 2023
1. INTRODUCTION
1u1 Ob'ec� tiv�
This study documents the results of a �_,,,���
comprehensive hydrologic and hydraulic �;� ` � ��.�'^�`= � � . �,� - � �- - - ��
analysis for the proposed ���� � �X � � ��' •-` '�
Timberline-International FDP project located in ��-� �"" •.��' � �
Fort Collins, Colorado. � ,'�t
��^� 6� �. ,
The project includes new 2,900 sf and 624 sf �`'" '���S ;
��
commercial buildings, new water and sewer ��� ���a., ,
services lines, site improvements, and an onsite �: `�' s`
stormwater detention pond (Photo 1). �i�Q�� 1-�r°��
1.2 Pro�ect IHi�toi9� aild Pr°evious StucYies
There are no known hydrologic or hydraulic studies for the Timberline-International
property.
1.3 Man�in$ and S��i9vevin�
Intermill Land Surveying, of Loveland, Colorado, provided field survey information and
topographic mapping of the project site, with a contour interval of 1-foot. The survey
was performed in June 2018, and was referenced to NGS Monuments F136 and C402 on
the NAVD88 datum, and the NAD 83, Colorado State Plane (UTM Zone 13) North Zone
survey coordinate system.
2. SITE LOCATION AND DESCRIPTION
2.1 Site Location
The project is located in the Southwest 1/4 of Section 8, Township 7 North, and Range 68
West of the 6th Principal Meridian, City of Fort Collins, Larimer County, Colorado.
The site is bounded by N. Timberline Road on the east, International Boulevard on the
south, Lake Canal on the west, and an existing commercial property on the north.
The project is located outside of any FEMA regulated floodplain, as per the FEMA Flood
Timberline-International FDP
June 29, 2023
Page 2
Wohnrade
� . clvil Engineers
Insurance Rate Map (FIRM), Community-Panel Number 08069C-0984H, effective on
May 2, 2012 (see Firmette).
The property is also located adjacent to the Lake Canal, which is not a City of Fort
Collins designated floodplain, as per the online mapping application FCMaps.
2.1 Sifi� �e�c�-i�ti���
The project site is roughly 1.39 acres in size and is located in a commercial area within
Larimer County, Colorado. The property is currently being annexed into the City of
Fort Collins, Colorado.
The site is currently undeveloped and contains an existing ditch access road, a fill pile,
and some existing utilities.
The site is located in the Dry Creek Drainage Basin, as defined by the City of Fort Collins
Master Drainage Plan. A future off-site storm sewer will be located parallel to the east
property line, which begins at East Ridge Second Filing, and ends at the Dry Creek
channel.
No offsite stormwater runoff enters the site from the adjacent property located to the
north. Stormwater runoff from South Timberline Road enters the property along the
east property line.
A geotechnical subsurface exploration report was prepared by CTL Thompson and is
dated October 1, 2018 (Reference 4). The subsurface materials encountered consist of
2 to 3 feet of sand and clay over sand and gravel. Groundwater was encountered in
three borings at the time of drilling at a depth of roughly 13-feet and was measured
three days later at depths ranging from 11.5-feet to 12 feet. Bedrock was not
encountered in any of the four borings within the property. The sand and gravel layer
wil] facilitate a Partial Infiltration Section as it relates to bioretention.
The USGS Web Soil Survey was also used to identify the hydrologic soils group within
the project limits. The site consists entirely of Group B type soils, which exhibits a
moderate infiltration rate.
3. PRE-PROJECT CONDITIONS
3.1 I're-Proiect Draina�e Basins
The existing project site includes a single onsite drainage basin that includes the entire
property for a total area of 1.39 acres. There is also a single off-site basin of 0.46
acres, which includes the west half of North Timberline Road.
3q2 �'re-[�roi��t l�raina�� ��tfi€�rn�
Stormwater runoff from the entire property drains overland, across gravel and
Timberline-International FDP
June 29, 2023
Page 3
Wohnrade
� . clvil Engineers
vegetated surfaces to Lake Canal, which bounds the property on the west and south.
Runoff calculations for the pre-project condition have not been performed, since the
maximum allowable developed release rate is a fixed 0.20 cfs/acre, and is independent
of the historic discharges.
4. POST-PROJECT CONDITIONS
4.1 Propos�d Project Descri�tic�n
The proposed project includes new 3,364 and 624 sf buildings, new asphalt parking and
drives, new underground utilities, and a new onsite stormwater detention facility.
The widening of N. Timberline Road to the west has also been accounted for in this
drainage analysis. The widening will include a right turn lane for southbound traffic
onto International Boulevard, and a northbound left-turn lane into the site. The street
widening has been designed and will be constructed as part of this development
proposal. Stormwater runoff from the west half of Timberline Road will be conveyed
along the west flowline of Timberline flowing north to south, and then continue west
along the north flowline of International Boulevard. There are no proposed storm
inlets in the adjacent streets as part of this future improvement.
The preliminary design of a 30-inch diameter off-site storm sewer has also been
included as part of this development proposal (See Appendix D). The off-site sewer
would be located in the center of the existing right-turn lane in N. Timberline Road. A
390-foot long section of this sewer would be constructed as part of this development.
Developed stormwater runoff will be discharged to Lake Canal at a rate not to exceed
0.20 cfs/acre. An agreement has been reached with Lake Canal Company, which
allows for this release. Final engineering plans and the drainage report have been
submitted to Lake Canal Company for review and comment. A written agreement for
this stormwater release has been executed by Lake Canal Company and is attached to
this report. WCE also provided revised civil construction plans to Lake Canal
Company on Apri16, 2021 for their review and comment. The release rate and
discharge location has not changed since the date of the executed agreement.
Standard water quality treatment and Low Impact Development (LID) has also been
incorporated into the stormwater design for this project, as per City of Fort Collins
criteria. The primary LID measure includes a rain garden to treat stormwater runoff
from 100% of the impervious surfaces.
The proposed road improvements to N. Timberline Road and International Boulevard
will necessitate the extension of the existing 6'H x 14'W RCB culvert in Lake Canal.
The existing box culvert will be extended 20-feet to the northwest, and will require a
new concrete headwall, wingwalls, and guardrail. Structural plans for the proposed
extension have been prepared by Weeks & Associates of Fort Collins, Colorado, and will
Timberline-International FDP
June 29, 2023
Page 4
be submitted to Lake Canal Company for review and approval.
4.2 Post-Pi�oi�ct Drain��e Basin�
Wohnrade
� . clvil Engineers
The proposed project site has been divided into 3 post-project drainage basins for a
total drainage area of 1.28 acres. Offsite Basin 01 (0.46 acres) extends from the
existing centerline in N. Timberline Road, to the proposed back of walk on the west side
of Timberline and includes the ultimate widening of Timberline.
Post-project drainage basins and patterns will generally mimic pre-project conditions,
with Basin 1 draining in the direction of Lake Canal directly to a detention facility and
Basin 2 draining to a bioretention area that overflows into the detention facility. The
detention facility will release developed runoff to Lake Canal at a rate not to exceed
0.20 cfs/acre, as per the Dry Creek Basin Master Drainage Plan.
i � � �; , . • ■
Basin 1(0.28 ac) drains overland across vegetated areas, at slopes ranging from 2.0% to
25%, to the new detention facility, and includes 100% pervious surfaces. The
drainage pattern within this basin will generally mimic pre-project drainage patterns.
The 10 and 100-year peak discharges are estimated to be 0.3 cfs and 0.8 cfs
respectively.
Basin 2(0.71 ac) drains overland across vegetated areas, and in vertical curb and
gutter, at slopes ranging from 1.67% to 25%, to the new bioretention area. Basin 2
includes 100% of the project impervious surfaces. The drainage pattern within this
basin mimics pre-project drainage patterns. The 10 and 100-year peak discharges are
estimated to be 2.4 cfs and 6.1 cfs respectively.
Basin 3(0.29 ac) drains overland across the new ditch access road (gravel surface), and
existing vegetated areas at slopes ranging from 1.55% to 4.0%, towards Lake Canal.
The drainage pattern within this basin mimics pre-project drainage patterns. The 10
and 100-year peak discharges are estimated to be 0.5 cfs and 1.2 cfs respectively.
Offsite Basin 01 (0.46 ac) drains overland across the pavement on Timberline Road to
the proposed vertical curb and gutter on the west side of the southbound lane. The 10
and 100-year peak discharges are estimated to be 1.9 cfs and 4.6 cfs respectively.
Calculations made as part of this investigation, along with other supporting material,
are contained in Appendix A.
4��Q� Pr��ms�d Deterlti�n Pc�nd
The proposed detention pond is located in the southeast portion of the property,
adjacent to Lake Canal. The pond will detain stormwater runoff from onsite Basins 1
and 2. Stormwater runoff from Basin 2 will be first be routed through the bioretention
area to meet LID requirements.
Timberline-International FDP
June 29, 2023
Page 5
Wohnrade
� . clvil Engineers
The pond has been designed to accommodate the 100-yr flood contro] volume. The
standard City of Fort Collins Water Quality Outlet Structure will be used to control the
100-year stormwater release.
The property lies within the Dry Creek Drainage Basin, which requires runoff from the
100-year developed storm to be released at a maximum rate of 0.20 cfs/ac.
Stormwater runoff from onsite Basins 1 and 2(0.99 acres) will be released at this rate.
Stormwater runoff from Basin 3 cannot be captured and routed to an onsite facility and
will therefore drain directly to Lake Canal. The maximum allowable release from the
developed site is 0.20 cfs/ac x 0.99 acres= 0.20 cfs.
As per Colorado Revised Statutes 37-92-602(8), criteria regarding detention drain time
will apply to this project. The spreadsheet (SDI_Design_Data_v1.08.xlsm) developed
by the UDFCD and State of Colorado Division of Water Resources has been used to
verify the 5 and 100-year drain times. The maximum time to drain 97% of all runoff
from a rainfall event that is less than or equal to a 5-year storm, is within 72 hours after
the end on the event. The estimated drain time for Pond 1 is 4.6 hours, which is much
less than the required maximum. The maximum time to drain 99% of all runoff for
events greater than the 5-year storm, is within 120 hours after the end of the event.
The estimated drain time for Pond 1 for storms greater than the 5-year event is 12.8
hours, which is much less than the maximum. The completed SDI_Design_Data
spreadsheet has been provided in Appendix B of this report.
The computer program, Hvdraflow Hydrogra�hs Extension for AutoCAD Civil 3D 2016
was used to route the 100-year design storm through the detention pond. The Storage
Indication Method was used to route the 100-yr design storm through the proposed
detention pond. An inflow hydrograph was developed to route the 100-year storm
through the detention pond, which includes Basins 1 and 2(0.99 acres).
Results of the pond routing predict a maximum 100-yr water surface elevation of
4935.91, with an associated storage requirement of 2,682 cu-ft. A 2.25" diameter
orifice will control the release of developed stormwater runoff at a maximum rate of
0.18 cfs. The 100-year storm was routed through the pond, beginning at an elevation
of 4934.00.
An emergency pond overflow weir has also been designed to pass the 100-year peak
inflow (7.1 cfs) to the pond. The notch elevation of the weir will be set at 4937.50, and
the top at an elevation of 4938.00, and will be 10' in width. The weir will direct
stormwater runoff to the historic discharge location, which is the Lake Canal.
Bioretention has also been incorporated into the Low Impact Development design.
The computer programs UD-BMP (v3.07), developed by the Mile High Flood District
(MHFD), has been used to calculate the required orifice size based on a 12-hour drain
time.
Timberline-International FDP
June 29, 2023
Page 6
Wohnrade
� . clvil Engineers
Stormwater runoff from all proposed impervious areas (Basin 2) will be routed through
a bioretention area for treatment. Calculations have been determined for this area,
based on fully developed conditions.
Based on the Rain Garden (RG) design procedure in the UD-BMP spreadsheet, the
calculated design volume for the bioretention area is 462 cu-ft and includes runoff from
onsite Basin 2. The total volume provided in the bioretention area from elevation
4936.5 to 4937.0 is 2,033 cu-ft.
Calculations made as part of this pond analysis, along with other supporting material,
are contained in Appendix C.
5. DESIGN CRITERIA
5.1 Design References
Drainage design criteria outlined in the City of Fort Collins Stormwater Criteria Manual
(Reference 1), and the Urban Storm Drainage Criteria Manual by the Mile High Flood
District (Reference 2), have been referenced in the preparation of this study.
5a2 Hvdre►lo i-�c �,i u��g4i�
Due to the relatively small basin size, and in keeping with criteria set forth in the City of
Fort Collins, Stormwater Criteria Manual, the Rational Method has been used to
estimate peak stormwater runoff from the project site.
The initial2 and 10-year, and major 100-year design storms have been used to evaluate
the proposed drainage system. Rainfall intensity data for the Rational Method has
been taken from IDF equations referenced in Table 3.4-1 of the City of Fort Collins
Stormwater Criteria Manual (Reference 1).
Runoff coefficients were derived using the equations described in Chapter 5, Section 3.2
of the Fort Collins Stormwater Criteria Manual. The area of all impervious surfaces
was determined for each drainage basin, including roads, walk, and roofs. It is a much
more laborious effort but provides a more realistic estimate of peak discharge from the
developed site.
Site specific rainfall data from the NOAA Precipitation Server is normally used on all
WCE projects, but will not be used on this project, as requested by the City. We
believe that using the site-specific rainfall data and determining the area of impervious
surfaces for each drainage basin results in the most accurate representation of peak
discharge from both the historic and developed sites. Using the City runoff coefficients
and citywide rainfall data generally results in lower overall peak discharges and won't
be as conservative as site specific data.
Timberline-International FDP
June 29, 2023
Page 7
6. EROSION CONTROL
�m1 Low Iirra���ct Desig�I�I��
Wohnrade
� . clvil Engineers
The proposed project has incorporated the 4-step process developed by the Mile High
Flood District (MHFD), for the protection of receiving waters downstream of the project
site. The BMP Selection Tool within the UD-BMP spreadsheet has been used to select
the appropriate BMPs for Steps 1 and 2 of the 4-step processes. The project
implements volume reduction strategies including grass swales, and BMPs including
Bioretention - Partial Infiltration Basins.
Low Impact Development (LID) is a comprehensive land planning and engineering
design approach to managing stormwater runoff with a goal of replicating the
pre-development hydrologic regime of urban and developing watersheds. Volume 3 of
the UDFCD Drainage Criteria Manual emphasizes LID criteria, including Minimizing
Directly Connected Impervious Areas (MDCIA) as the first step in stormwater quality
planning and has provided guidance on LID techniques such as grass swales, grass
buffers, permeable pavement systems, bioretention, and pollution prevention
(pollutant source controls).
Low Impact Development (LID) design will be required for this project using methods
and techniques described in Volume 3, Chapter 1, Section 4.1, Runoff Reduction
Practices. The opportunity to implementation multiple LID techniques is limited, due
to the size of the site (1.39 acres). Surface runoff from impervious areas drains to the
bioretention area. The length and depth of grass buffers and grass swales is employed
to some extent but is limited.
The project has also been designed to minimize impacts to the site, and conserve
existing amenities. One example of this would be minimizing the disturbance in
drainage Basin 3 along the east side of Lake Canal, and retaining the existing vegetation.
With the exception of a small portion of the drive entrance, nearly 100% of all newly
added or modified impervious area will be treated by LID techniques, which complies
with criteria set forth in the City of Fort Collins Stormwater Criteria Manual, Chapter 7,
Section 6.0, Low lmpact Development. The technique to be employed will include a
bioretention area (rain garden), which will be located adjacent to the stormwater
detention pond. The clayey sand, and sand and gravel layer will facilitate a Partial
Infiltration Section as it relates to bioretention. A perforated underdrain will be
installed beneath the bioretention area in order to hydraulically connect the area to the
detention pond.
Calculations made as part of this LID analysis, along with other supporting material, are
contained in Appendix C.
F„2 ���o�ion Contr�I �'I�n
A proposed rainfall erosion control plan during construction will consist of temporary
Timberline-International FDP
June 29, 2023
Page 8
structural erosion control measures.
Wohnrade
� . clvil Engineers
Erosion control measures have been specified on
the Grading and Erosion Control Plan, and on three separate drawings contained in the
written Stormwater Management Plan (SWMP). These drawings include a
Pre-disturbance, Interim, and Final Stabilization Plans.
Wohnrade Civil Engineers, Inc. will prepare a separate report containing the
Stormwater Management Plan (SWMP) for this project. A Colorado Discharge Permit
System (CDPS), Stormwater Discharge Associated with Construction Activities
application will also be submitted to the Colorado Department of Public Health and
Environment.
A City of Fort Collins Erosion and Sediment Control Escrow/Security Calculation has
been prepared for this project, and will be included in the written SWMP report.
�m3 Site St�l�'r���ation
All areas disturbed by construction will be landscaped, paved, or re-seeded using the
recommended seed varieties, quantities, and application rates as specified on the
project Landscape Plan.
7. CONCLUSIONS
i„1 Com�liance �vith Stand��ds
The proposed drainage improvements been designed to comply with all applicable
drainage criteria, in accordance with the City of Fort Collins Stormwater Criteria
Manual.
7�2 Varian���
There are no variances requested as part of this stormwater drainage design.
8. REFERENCES
1. Stormwater Criteria Manual. City of Fort Collins, adopted December 2011.
2. Urban Storm Drainage Criteria Manual, Mile High Flood District, Denver, Colorado,
Revised Apri12008.
3. CDOT Drainage Design Manual. Colorado Department of Transportation.
4. Geotechnical Investigation. Proposed Commercial Development, Lot 1, Industrial
Business Park. CTL Thompson, Inc., October 1, 2018.
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�� HOLDINGS
125 S. Howes Street 2�d Floor
Fort Collins, CO 80521
Justin Green
Lake Canal
Sent via email: justin@lakecanal.com
RE: Requested Storm Water Outfall into Lake Canal
Mr. Green;
FR Holdings, Ltd. is the owner of Lot 1 in the Industrial Business Park PUD in Fort Collins, a 1.39
acre parcel that borders Lake Canal at the north west intersection of Timberline Road and
International Boulevard.
We are pursuing a small mixed-use commercial development on our property. In our initial
conversations with the City of Fort Collins, we were asked to construct and pay for a
comprehensive master-planned storm drainage system along Timberline Road which would run
not only along our eastern frontage, but further south several hundred yards, well beyond our
property boundary. This request is obviously cost prohibitive. As an alternative, City staff
proposed a storm water outfall agreement with Lake Canal. Staff inentioned that other projects
in the area have made similar arrangements with Lake Canal.
Enclosed is a preliminary design for our project including an outfall structure into the canal as
well as a flow calculation from our site based on a 100-year event. We are requesting approval
from Lake Canal for this discharge, and understand there will be an annual fee associated with
the same.
Please contact me directly with any questions.
Thank you,
� -
Devin Ferrey
President, FR Holdings, Ltd.
devin@fr-corp.com
970-691-1234
AGREEMENT TO ALLOW DISCHARGE OF DRAINAGE WATER
INTO THE LAKE CANAL DITCH
�
THIS AGREEMENT is made and entered into this � day of May, 2019, by and
between THE LAKE CANAL COMPANY OF COLORADO, a Colorado non-profit mutual
irrigation company (hereinafter the "Company"), and FR Holdings, Ltd., a Colorado limited
liability company, whose address is 125 S. Howes Street, 2°`� Floor, Fort Collins, CO 80521,
("FR Holdings" or "Landowner").
RECITALS
WHEREAS, Company is the operator of a Ditch or ditch known as Lake Canal
(hereinafter called the "Ditch"). The Ditch transports water and a portion of the Ditch exists ancl
travels over a tract of land cw�rently owned by Landowner at the northwest corner of the
intersection of L�ternational Boulevard and N. Timberline Road a/k/a Lot 1 of Industrial
Business Park Interna[ional PUD, Fort Collins, Larimer City Colorado. The tract of land owned
by Landowner is being developed into an mixed use commercial development and a portion of
the Ditch exists and travels through part of the NE'/a of the SW'/a of Section 8, Township 7
North, Range 68 West of the 6`t' P.M., Larimer City, Colorado, and more particularly described
on [he attached Exhibit A, which is incorporated herein by this reference (hereinafter called
"Landowner's Tract"); and
WHEREAS, as a condition of approval of the FR Holdings development by the City of
Fort Collins ("City'"), Landowner is required to acquire permission to discharge historical
drainage water from the Landowner's Tract into the Ditch; and
WHEREAS, FR Holdings desires to construct and install drainage improvements and
related appurtenances as required by the City of Fort Collins as contained in the final drainage
plan and construction plans for the FR Holdings location (the "Improvements"), including but
not limited to two detention ponds with an outlet structure. The detention ponds will discharge
historical drainage into Lake Canal at the proposed discharge location; and
WHEREAS, the Improvements are shown on the construction plans and final drainage
report for FR Holdings as approved by the City as part of the development approval process; and
WHEREAS, the purpose of this Agreement is to set forth the terms and conditions for
the grant of a license to FR Holdings for the discharge of historical drainage water from the
Landowner's Tract into the Ditch, and for a temporary easement for construction the necessary
drainage Improvements.
NOW, THEREFORE, in consideration in the amount $200.00 annually and the mutual
promises contained herein, and for other good and valuable consideration, the receipt of which is
hereby acknowledged by the Company and the Landowner, the parties mutually agree as
follows:
The above Recitals are incorporated herein as if fully set forth.
Company grants to FR Holdings a temporary license for the construction and installation
of the Improvements. The Company also grants to FR Holdings a license to allow historical
drainage water, restricted to the amounts and from the sources historically discharging into the
Ditch, and to the location as shown in the October 9, 2018 "Drainage Design Considerations for
the Timberline---lnternational FDP, Fort Collins, Colorado" "as finally approved by the City
(the "Construction Plans") to be discharged into the Ditch. The area of construction and
installation of the Improvement are collectively referred to herein as the "Premises". The rights
and licenses granted herein shall include the right of ingress and egress over and across the
Premises, as depicted on the Construction Plans, for purposes of construction and installation of
the Improvements. Subject to the terms and conditions set forth in this Agreeinent, Co►npany
agrees to allow the historical flows and drainage from FR Holdings to the Ditch, so long as such
water discharge complies with the terms and conditions set forth in this Agreement, including
but not limited to the water quality standards and conditions described in paragraph ]0 herein.
2. FR Holdings will construct the Improvements at its sole expense in accordance
with the Construction Plans, which have been designed by a Colorado-licensed, professional
engineer and which shall in all respects conform to City storm water and drainage water
requirements.
3. Prior to the commencement of any construction, maintenance or repair of the
Impru�-cments, FR Holdings shall submit to the Company for its writ�en approval detailed plans
for such work. No construction on the Improvements will be permitted until the Company has
approved the plans. The Company represents that it has reviewed and approved the current plans
dated March 7, 2018. Upon completion of the project, FR Holdings shall submit an As-Built
sw�vey to the Company.
4. FR Holdings shall notify the Company at least 48 hours prior to the start of
construclion of, modifications or repairs to the Improvements, so that the Company may
supervise and inspect the work as it deems necessary. In the event the Company deems it
necessary to retain an engineer for supervision of FR Holdings' work on the Improvements, FR
Holdings shall be responsible for the reasonable fees and costs of such engineer.
5. FR Holdings shall be solely responsible for all costs associated with the
COIISU'UCL1011, maintenance, repair and replacement or the Improvements. In the event, however,
that any sum is reasonably expended by the Company for emergency repair or maintenance of
the Improvements, FR Holdings shall reimburse the Company for such expense. In the event
that the Company finds it necessary to make emergency repairs to the Improvements, the
Company shall be without liability for damage to FR Holdings, except as to such damage as may
be caused by gross negligence or wanton and willful misconduct of the Company.
Determination of whether repair or maintenance is necessary and whether an emergency exists
shall be in the sole discretion of the Company.
6. In carrying out its rights and duties under this Agreement, FR Holdings will use
all reasonable means to prevent any disturbance of the flow of water in the Ditch, unless
permission in writing is first received from the Company for such disturbance. FR Holdings
shall be responsible for any damages resulting from the unauthorized disturbance of flow of
water through the Ditch caused by FR Holdings. Construction of the Improvements shall be
completed within 30 days from commencement of construction, unless written consent by the
Company for an extension is granted, and shall be accomplished during the non-irrigation
season, unless otherwise agreed by the Company.
7. The Company reserves its full power to operate, maintain, alter, enlarge, relocate,
clean and manage its Ditch and installations. In the event that the Company finds it necessary to
perform emergency repairs to its Ditch or installations, either now or at any future time, the
Company shall be wholly without liability for damages to FR Holdings as the result of the
performance of said repairs, except as to such damage as may be caused by the negligence or
misconduct of the Company, its contractors, agents or employees. Determination of whether an
emergency exists shall be at the sole discretion of the Company.
8. Beginning in 2019, FR Holdings will pay to the Company on or before April l S` of
each year an annual fee in perpetuity for the rights herein granted, which fee shall be $200.00 or
one-half times the amount annually assessed by the Company on one share of The Lake Canal
Company of Colorado stock, whichever is greater. FR Holdings agrees that it will be responsible
for payment of the annual fee due to the Company. In the event that the annual fee required
under tllis paragraph is not timely paid, in addition to other remedies provided in this Agreement,
interest on the amount unpaid shall accrue at 12�Io per annum until paid, or the amount of interest
then charged by the Company to a shareholder who is delinc�uent on payment of his or her
assessment until paid, whichever is greater.
9. FR Holdings shall ensure that appropriate and effective permanent water
cleansing practices, techniques and apparatuses are installed and utilized, designed to effectively
clean any waters to be drained into the Ditch under this Agreei��ent. FR Holdings shall ensure
that all water quality practices, techniques and apparatuses that cleanse the drainage water arising
on the Property are properly and effectively working at all times, and FR Holdings shall annually
maintain and inspect such practices, techniques and apparatuses.
10. At a minimwn any water contemplated by this Agreement to drain through or
from the Improvements into the Ditch shall at all times be suitable for agricult�ira] �ise, including
the watering of livestock, be non-hazardous to humans, be non-malodorous and otherwise
suitable for its historic uses, and shall be suitable for any other use or uses that the waters may be
put to by the Company's shareholders, now or in the future; and at a minimum such waters shall
meet the then current local, state and federal water quality standards for point source discharges
into a public waterway in which the waters ultimately may be discharged under the then
applicable public waterways classification at such point of discharge. In any event, however,
any drainage waters that enter the Ditch from the Property shall at all times be of a water quality
that complics with the provisions of any lawful statute, regulation or ordinance of general
applicability limiting, regulating or prescribing the quality of water that may be used for
agricultural irrigation and any other use or uses that the waters may be put to by the shareholders
now or in the future, including modifications thereof, and whether adopted by the State Engineer
or any other local, state or federal governmental agency. FR Holdings may request from the
Company a description of the uses to which the waters in the Ditch are put, but such request may
3
be made not more than once per year. At least once per year, and at such other times as
Company may reasonably request, FR Holdings (at FR Holdings' cost), will retain a qualified
water quality expert (reasonably selected by the Company) to sample test (to the extent
reasonably requested by Company) the drainage waters entering the Ditch from the Property, to
ensure that the water quality standards recited herein are not violated. The results of such
sampling and testing will be provided to the Company without cost.
11. FR Holdings, its successors and assigns, shall forever hold the Company, its
employees, officers and its directors harmless from liability for damage to the Company and its
shareholders resulting from FR Holdings failure to meet the water quality standards stated in this
paragraph 10. Further, FR Holdings agrees that in the event any shareholder of the Company or
third party brings suit against the Company, its officers, directors or employees, as a result of FR
Holdings' violation of the water quality standards contained in this Agreement, FR Holdings, its
successors and assigns, will indemnify the Company and its officers, directors, and employees
for the cost to defend said suit and for any claim for damages.
A. In the event that FR Holdings violates the water quality standards recited in this
paragraph 10, FR Holdings shall be liable to Company for actual damages incurred by the
Company or for liquidated damages in the amount of $1,000.00 for each day of the violation,
whichever is less. Annually, upon the anniversary date of this Agreement, the amount of
liquidated damages shall increase by three percent (3%) to reflect inf1ation.
B. Notwithstanding the provisions of Paragraph A above, Company may seek
judicial or administrative relief or other appropriate remedies and damages. In the event that a
court or governmental body requires or orders that the water discharged by FR Holdings into the
Ditch requires treatment to cure a violation, FR Holdings shal) effectuate s��ch treatment at its
sole expense to meet the terms of this Agreement.
C. In the event that a local, state or federal governmental agency or authority or any
court of competent jurisdiction requires Company to obtain, or asserts that Company must obtain
or was required to obtain, any permit, authorization, or similar approval to allow the Company [o
receive historical flows and drainage water pursuant to this Agreement, or for the Company to
allow any installation, repair, maintenance or existence of the Improvements, then FR Holdings
shall obtain such permit, authorization or similar approval on behalf of the Company. Company
shall not be responsible for obtaining, 317y such permit, authorization or similar approval,
however, Company shall fully cooperate with FR Holdings in such process. In the event that any
administrative, judicial or similar proceeding is brought against the Company, its officers,
directors and employees due to the existence or nonexistence of any such permit, approval or
similar authorization, FR Holdings shall indemnify the Company, its officers, directors,
employees and shareholders from any liability or damages, and shall pay the Company's
reasonable attorney fees and costs incurred in connection with any such proceeding.
12. In addition, FR Holdings hereby covenants and agrees:
A. FR Holdings shall not install a fence, nor construct any building within the
Premises unless written authorization is first received by the Company.
�
B. Upon completion of the Improvements or other work performed by FR Holdings
pursuant to this Agreement, FR Holdings, to the extent practicable, shall restore the Premises to
its original state as nearly as reasonably possible; to at least equal to the condition it was in
immediately prior to the date of this Agreement, except as necessarily modified to accommodate
the Improvements.
C. In the event the Improvements, or other work performed pursuant to this
Agreement, causes settling in the Ditch, FR Holdings will upon notification from Company,
immediately restore the Ditch to its original state as nearly as reasonably possible, to at least
equal to the condition it was in immediately prior to the date of this Agreement, except as
necessarily modified to accommodate the Improvements.
D. Each party shall bear his, her, or its own costs of any legal services necessary in
the preparation and implementation of this Agreement, except as previously agreed between the
parties wherein FR Holdings agreed to reimburse Company for all reasonable engineering, legal
and administrative costs incurred by the Company in preparing and approving this Agreement.
13. FR Holdings shall indemnify the Company, its officers, directors and employees,
defend, and forever hold it and them harmless from liability for damage or injury to the
Company, its shareholders, and third persons resulting from this Agreement, its existence, or any
construction, repair, use or operation in connection therewith.
14. Failure by the Company to enforce any or all provisions of this Agreement at any
time does not, and shall not operate as a waiver or estup}���.
15. This Agreement, and any grant by Company, is subject to all restrictions,
reservations, rights-of-way, easements, documents or agreements existing or of record in the
Larimer Ciry Clerk and Recorder's Office at the time this Agreement is recorded. The Company
makes absolutely no warranties, including warranties of title, in oc by this Agreement or any
grant herein.
16. This Agreement and all the terms and conditions hereof shall extend to and be
binding upon the successors and assigns of each of the parties hereto. This Agreement shall run
with the land.
17. FR Holdings shall, at the time of submitting this Agreement to the Company for
approval and signature, provide to the Company cash or a check payable to the Larimer City
Clerk and Recorder in an amount sufficient to pay the cost of recording this Agreement with the
Larimer City Clerk and Recorder. The installation of the Improvements shall not commence
until this Agreement has been recorded.
18. Any notice required or pertnitted hereunder shall be deemed effective when
deposited in the United States mail, postage prepaid, first class and addressed to the party to
whom notice is to be given, as follows:
5
If to Company: The Lake Canal Company of Colorado
c/o Fischer, Brown, Bartlett & Gunn, P.C.
Attn: Brent Bartlett
1319 E. Prospect Road
Fort Collins, CO 80525
Lake Canal Company of Colorado
c/o Alden V. Hill, Secretary-Treasurer
160 West Mountain
POBox421
Fort Collins, CO 80522
With a copy to: Registered Agent as reflected in the records of the
Colorado Secretary of State
If to FR Holdin�s :
FR Holdings, Ltd.
125 South Howes Street, 2°d Floor
Fort Collins, CO 80521
Said notice to the Company shall not be effective unless a copy of any notice is also
similarly mailed to the Company's registered agent as filed with the Colorado Secretary of
State's Office.
In the event that the person or entity to whom notice shall be given changes, the other
party shall be notified in writing pursuant to ehis paragraph.
(remainder of page inte��tionally left blc��ik)
0
IN WITNESS WHEREOF, the parties hereto have caused these presents to be duly
executed by the proper officer and have affixed their seals hereto on the day and year first above
written.
FR Holdings, Ltd.,
a Colorado limited liability company
BY:
Devin Fer �ey, Manager
STATE OF COLORADO )
) ss.
CITY OF LARIMER )
The foregoing instrument was acknowledged before me this ��day of May, 2019, by
Devin Ferrey as Manager of FR Holdings, Ltd., a Colorado limited liability company.
� �
WITNESS my hand and official seal. �
Notary Public:
My commission expires: � � �
BRENDA WILSON
NOTARY PUBLIC
STATE OF COLORADO
NOTARY �D 2o»aoo�st7 THE LAKE CANAL COMPANY OF
MY COMMISSION EXPIRES FEB. 17, 2021 COLORADO
By:
Rodney . Nelson, President
STATE OF COLORADO )
) ss.
CITY OF LARIMER )
The foregoing instrument was acknowledged before me this !�day of May, 2019, by
Rodney L. Nelson as President of The Lake Canal Company of Colorado.
WITNESS my hand and official seal. _-�%v(���C .
Notary Public:
My commission expires: !�
MEUSSA H. BUICK �
NOTARY PUBLfC
'7 STATE OF COI.ORADO
NOTARY ID 20054024373
MY COMMISSION EXPIRES JULY 6, 202 •
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Appendix A
Timberline-International
Preliminary Development Plan
April 6, 2021
Runoff Coefficient Calculations Wohnrade
Civi! Engineers
Post-Project Condition, Basin 1
NRCS Soil Type B
Surface Type
Area (acres)
Runoff Coefficients
Total Area (acres)
Asphalt Gravel Concrete
0.000 0.000 0.003
0.95 0.5 0.95
0.28
Rooftop Lawns, Composite
Clayey Runoff
Soil, Avg Coefficient
Slope
0.000 0.277 0.26
0.95 0.25
Runoff coefficient equations taken from Table 3.2-2 of the Fort Collins Stormwater Criteria Manual,
Chapter 5, Section 3.2
2-Year 5-Year
0.26 0.26
Storm Return Period
10-Year 25-Year 50-Year
0.26 0.28 0.31
Post-Project Condition, Basin 2(Rain Garden Inflow)
NRCS Soil Type B
Surface Type
Area (acres)
Runoff Coefficients
Total Area (acres)
Asphalt Gravel Concrete
0.269 0.000 0.098
0.95 0.5 0.95
0.71
100-Year
0.32
Rooftop Lawns, Composite
Clayey Runoff
Soil, Avg Coefficient
Slope
0.087 0.256 0.70
0.95 0.25
Runoff coefficient equations taken from Table 3.2-2 of the Fort Collins Stormwater Criteria Manual,
Chapter 5, Section 3.2
Storm Return Period
2-Year 5-Year 10-Year 25-Year 50-Year 100-Year
0.70 0.70 0.70 0.77 0.84 0.87
Page 1 of 3
Timberline-International
Preliminary Development Plan
April 6, 2021
Runoff Coefficient Calculations � Wohnrade
'� ��Civi' Enc�ineers
Post-Project Condition, Basin 3
NRCS Soil Type B
Surface Type
Area (acres)
Runoff Coefficients
Total Area (acres)
Asphalt Gravel Concrete
0.000 0.090 0.000
0.95 0.5 0.95
0.29
Rooftop Lawns, Composite
Clayey Runoff
Soil, Avg Coefficient
Slope
0.000 0.200 0.33
0.95 0.25
Runoff coefficient equations taken from Table 3.2-2 of the Fort Collins Stormwater Criteria Manual,
Chapter 5, Section 3.2
2-Year 5-Year
0.33 0.33
Post-Project Condition, Basin 01
NRCS Soil Type B
Surface Type
Area (acres)
Runoff Coefficients
Total Area (acres)
Storm Return Period
10-Year 25-Year 50-Year
0.33 0.36 0.39
Asphalt Gravel Concrete
0.367 0.000 0.038
0.95 0.5 0.95
0.46
100-Year
0.41
Rooftop Lawns, Composite
Clayey Runoff
Soil, Avg Coefficient
Slope
0.000 0.055 0.87
0.95 0.25
Runoff coefficient equations taken from Table 3.2-2 of the Fort Collins Stormwater Criteria Manual,
Chapter 5, Section 3.2
Storm Return Period
2-Year 5-Year 10-Year 25-Year 50-Year 100-Year
0.87 0.87 0.87 0.95 1.00 1.00
Page 2 of 3
Timberline-International
Preliminary Development Plan
April 6, 2021
Runoff Coefficient Calculations � Wohnrade
' �Civi! Engineers
Post-Project Condition, Basins 1& 2(Detention Pond Inflow)
NRCS Soil Type B
Surface Type
Area (acres)
Runoff Coefficients
Total Area (acres)
Asphalt Gravel Concrete
0.269 0.000 0.101
0.95 0.5 0.95
0.99
Rooftop Lawns, Composite
Clayey Runoff
Soil, Avg Coefficient
Slope
0.087 0.533 0.57
0.95 0.25
Runoff coefficient equations taken from Table 3.2-2 of the Fort Collins Stormwater Criteria Manual,
Chapter 5, Section 3.2
Storm Return Period
2-Year 5-Year 10-Year 25-Year 50-Year 100-Year
0.57 0.57 0.57 0.63 0.69 0.72
Page 3 of 3
Post-Project Conditions
2-Yr Runoff Computations
Overland Flow, Time of Concentration:
T;= 1.87(1.1-CxCf)L��2 / S��3
Gutter/Swale Flow, Time of Concentration:
Tt= L / 60V
T�= T; + Tt
Intensity, (i) taken from intensity formula for Timberline-International PDP, i=30.04/(T�+11.30)o.s4
Velocity, (V) taken from Figure 3-1
Rational Equation: Q = ciA
Design
Point
1
2
3
01
1
Upstream
Time of Runoff
Concentration Area, A Coefficient
Baslns Tc (acres) c
1 0.0 0.28 0.26
2 0.0 071 0.70
3 0.0 0.29 0.33
01 0.0 0.46 0.87
1,2 0.0 0.99 0.57
Overland Flow
C5 (ft)
0.26 33.8
0.70 22.3
0.33 25.0
0.87 52.3
0.57 33.8
( % ) (min)
2.7 6.6
2.4 2.6
3.2 4.9
5.0 1.8
2.7 4.1
(fps) (min)
0.00 0.0
0.00 0.0
0.00 0.0
129 3.0
0.00 0.0
Gutter/Pipe Flow
(n) ��)
0.0 0.0
0.0 0.0
0.0 0.0
233.3 0.4
0.0 0.0
Note:
Rainfall intensity values were generated using Table 3.4-1 of the Fort Collins Stormwater Criteria Manual
(ft)
147.0
186.4
0.0
0.0
147.0
Calculations b
Proiect: Timb
Date: April 6, ;
Swale Flow
(%) (fps)
4.8 3.53
1.9 2.22
0.0 0.00
0.0 0.00
4.8 3.53
TIM-DevQ.xlsx Page 1 of 3
Post-Project Conditions
10-Yr Runoff Computations
Overland Flow, Time of Concentration:
T;= 1.87(1.1-CxCf)L��2 / S��3
Gutter/Swale Flow, Time of Concentration:
Tt= L / 60V
T�= T; + Tt
Intensity, (i) taken from intensity formula for Timberline-International PDP, i=46.95/(T�+10.60)o.s3
Velocity, (V) taken from Figure 3-1
Rational Equation: Q = ciA
Design
Point
1
2
3
01
1
Upstream
Time of Runoff
Concentration Area, A Coefficient
Baslns Tc (acres) c
1 0.0 0.28 0.26
2 0.0 071 0.70
3 0.0 0.29 0.33
01 0.0 0.46 0.87
1,2 0.0 0.99 0.57
Overland Flow
C5 (ft)
0.26 33.8
0.70 22.3
0.33 25.0
0.87 52.3
0.57 33.8
( % ) (min)
2.7 6.6
2.4 2.6
3.2 4.9
5.0 1.8
2.7 4.1
(ft)
147.0
186.4
0.0
0.0
147.0
Gutter/Pipe Flow
(ft) (%)
0.0 0.0
0.0 0.0
0.0 0.0
233.3 0.4
0.0 0.0
(fps) (min)
0.00 0.0
0.00 0.0
0.00 0.0
129 3.0
0.00 0.0
Note:
Rainfall intensity values were generated using Table 3.4-1 of the Fort Collins Stormwater Criteria Manual
Calculations b
Proiect: Timb
Date: April 6, ;
Swale Flow
(%) (fps)
4.8 3.53
1.9 2.22
0.0 0.00
0.0 0.00
4.8 3.53
TIM-DevQ.xlsx Page 2 of 3
Post-Project Conditions
100-Yr Runoff Computations
Overland Flow, Time of Concentration:
T;= 1.87(1.1-CxCf)L��2 / S��3
Gutter/Swale Flow, Time of Concentration:
Tt= L / 60V
T�= T; + Tt
Intensity, (i) taken from intensity formula for Timberline-International PDP, i=98.31/(T�+10.80)o.s3
Velocity, (V) taken from Figure 3-1
Rational Equation: Q = ciA
Design
Point
1
2
3
01
1
Upstream
Time of Runoff
Concentration Area, A Coefficient
Baslns Tc (acres) c
1 0.0 0.28 0.32
2 0.0 071 0.87
3 0.0 0.29 0.41
01 0.0 0.46 1.00
1,2 0.0 0.99 072
Overland Flow
C5 (ft)
0.26 33.8
0.70 22.3
0.33 25.0
0.87 52.3
0.57 33.8
( % ) (min)
2.7 6.1
2.4 1.5
3.2 4.4
5.0 0.8
2.7 3.0
(ft)
147.0
186.4
0.0
0.0
147.0
Gutter/Pipe Flow
(ft) (%)
0.0 0.0
0.0 0.0
0.0 0.0
233.3 0.4
0.0 0.0
(fps) (min)
0.00 0.0
0.00 0.0
0.00 0.0
129 3.0
0.00 0.0
Note:
Rainfall intensity values were generated using Table 3.4-1 of the Fort Collins Stormwater Criteria Manual
Calculations b
Proiect: Timb
Date: April 6, ;
Swale Flow
(%) (fps)
4.8 3.53
1.9 2.22
0.0 0.00
0.0 0.00
4.8 3.53
TIM-DevQ.xlsx Page 3 of 3
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l ']11-1'1'TR-no, ti������nd Ed...lunt� 1!is�fil
EQUATION
PAVED:
UNPAVED:
s= slope
FOR FIGURE 3-1:
V=20.3282(s)o.5
V=16.1345(s)o.5
in ft/ft
Project:
LEG' f70Z00
Oate:
osr»r»
s�a�e:
N.A.
Designed By:
N.A.
F/GUf�E 3-1
AVERAGE VELOCITIES
FOR SHALLOW
CONCENTRATED FLOW
WOHNRADE C/V/L ENG/NEERS, /N
11582 Co%ny Row
Broomfe/d, Co/orodo, 80027
Phone: (720J259-0965, Fax: (720J259-1519 �
1
Sheet
�
Sheets
1 2 4 6 10 20
FORT COLLINS STORMWATER CRITERIA MANUAL
Hydrology Standards (Ch. 5)
3.0 Rational Method
Table 3.4-1. IDF Table for Rational Method
Duration
Intensity Intensity Intensity
2-year 10-year 100-year
(min) �in/hr) (in/hr) (in/hr)
5 2.85 4.87 9.95
6 2.67 4.56 9.31
7 2.52 4.31 8.80
8 2.40 4.10 8.38
9 2.30 3.93 8.03
10 2.21 3.78 7.72
11 2.13 3.63 7.42
12 2.05 3.50 7.16
13 1.98 3.39 6.92
14 1.92 3.29 6.71
15 1.87 3.19 6.52
16 1.81 3.08 6.30
17 1.75 2.99 6.10
18 1.70 2.90 5.92
19 1.65 2.82 5.75
20 1.61 2.74 5.60
21 1.56 2.67 5.46
22 1.53 2.61 5.32
23 1.49 2.55 5.20
24 1.46 2.49 5.09
25 1.43 2.44 4.98
26 1.4 2.39 4.87
27 1.37 2.34 4.78
28 1.34 2.29 4.69
29 1.32 2.25 4.60
30 1.30 2.21 4.52
31 1.27 2.16 4.42
32 1.24 2.12 4.33
33 1.22 2.08 4.24
34 1.19 2.04 4.16
35 1.17 2.00 4.08
36 1.15 1.96 4.01
37 1.16 1.93 3.93
38 1.11 1.89 3.87
r� t`��
Duration
Intensity Intensity Intensity
2-year 10-year 100-year
(min) �in/hr) (in/hr) (in/hr)
39 1.09 1.86 3.8
40 1.07 1.83 3.74
41 1.05 1.80 3.68
42 1.04 1.77 3.62
43 1.02 1.74 3.56
44 1.01 1.72 3.51
45 0.99 1.69 3.46
46 0.98 1.67 3.41
47 0.96 1.64 3.36
48 0.95 1.62 3.31
49 0.94 1.6 3.27
50 0.92 1.58 3.23
51 0.91 1.56 3.18
52 0.9 1.54 3.14
53 0.89 1.52 3.10
54 0.88 1.50 3.07
55 0.87 1.48 3.03
56 0.86 1.47 2.99
57 0.85 1.45 2.96
58 0.84 1.43 2.92
59 0.83 1.42 2.89
60 0.82 1.4 2.86
65 0.78 1.32 2.71
70 0.73 1.25 2.59
75 0.70 1.19 2.48
80 0.66 1.14 2.38
85 0.64 1.09 2.29
90 0.61 1.05 2.21
95 0.58 1.01 2.13
100 0.56 0.97 2.06
105 0.54 0.94 2.00
110 0.52 0.91 1.94
115 0.51 0.88 1.88
120 0.49 0.86 1.84
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 8
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Hydrologic Soil Group
Lot 1. Industrial Business Park
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
7 Ascalon sandy loam, 0 B 1.4 100.0%
to 3 percent slopes
Totals for Area of Interest 1.4 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff.� None Specified
USDA Natural Resources Web Soil Survey 7/22/2018
� Conservation Service National Cooperative Soil Survey Page 3 of 4
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
Table 3.2-2. Surface Type - Runoff Coefficients
Surface Type Runoff Coefficients
Hardscape or Hard Surface
Asphalt, Concrete 0.95
Rooftop 0.95
Recycled Asphalt 0.80
Gravel 0.50
Pavers 0.50
Landscape or Pervious Surface
Lawns, Sandy Soil, Flat Slope < 2% 0.10
Lawns, Sandy Soil, Avg Slope 2-7% 0.15
Lawns, Sandy Soil, Steep Slope >7% 0.20
Lawns, Clayey Soil, Flat Slope < 2% 0.20
Lawns, Clayey Soil, Avg Slope 2-7% 0.25
Lawns, Clayey Soil, Steep Slope >7% 0.35
3.2.1 Composite Runoff Coefficients
Drainage sub-basins are frequently composed of land that has multiple surface types or zoning
classifications. In such cases a composite runoff coefficient must be calculated for any given drainage
sub-basin.
The composite runoff coefficient is obtained using the following formula:
�,
� �C; xA; �
� _ !=1
A,
Where: C= Composite Runoff Coefficient
C; = Runoff Coefficient for Specific Area (A;), dimensionless
A; = Area of Surface with Runoff Coefficient of C;, acres or square feet
n= Number of different surfaces to be considered
At= Total Area over which C is applicable, acres or square feet
3.2.2 Runoff Coefficient Frequency Adjustment Factor
Equation 5-2
The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year
storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is
required due to the lessening amount of infiltration, depression retention, evapotranspiration and other
losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is
r=-��� ��` 3.2 Runoff Coefficients
r�tf Page 5
Table 6-3. Recommended percentage imperviousness values
Land Use or Percentage lmperviousness
Surface Characteristics �%�
Business:
Downtown Areas 95
Suburban Areas 75
Residential lots (lot area only):
Single-family
2.5 acres orlarger 12
0.75 — 2.5 acres 20
0.25 — 0.75 acres 30
0.25 acres or less 45
Apartments 75
Industrial:
Light areas 80
Heavy areas 90
Parks, cemeteries l 0
Playgrounds 25
Schools 55
Railroad yard areas 50
Undeveloped Areas:
Historic flow analysis 2
Greenbelts, agricultural 2
Off-site flow analysis (when land use not 45
defined)
Streets:
Paved 100
Gravel (packed) 40
Drive and walks 90
Roofs 90
Lawns, sandy soil 2
Lawns, clayey soil 2
6-8 Urban Drainage and Flood Control District March 2017
Urban Storm Drainage Criteria Manual Volume 1
Hydraflow Rainfall Report
Hydraflow Hydrographs Extension for AutodeskOO Civil 3DOO by Autodesk, Inc. v2020
Return Intensity-Duration-Frequency Equation Coefficients (FHA)
Period
(Yrs) B D E (N/A)
1 0.0000 0.0000 0.0000 --------
2 30.0397 11.3000 0.8439 --------
3 0.0000 0.0000 0.0000 --------
5 0.0000 0.0000 0.0000 --------
10 46.9523 10.6000 0.8251 --------
25 0.0000 0.0000 0.0000 --------
50 0.0000 0.0000 0.0000 --------
100 98.3129 10.8000 0.8304 --------
File name: TIM.IDF
Intensity = B / (Tc + D)^E
Wednesday, 03 / 24 / 2021
Return Intensity Values (in/hr)
Period
(Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60
1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
2 2.85 2.27 1.90 1.64 1.45 1.30 1.18 1.08 1.00 0.93 0.87 0.82
3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
10 4.87 3.87 3.23 2.79 2.46 2.21 2.01 1.84 1.70 1.59 1.49 1.40
25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
100 9.94 7.91 6.61 5.71 5.04 4.52 4.11 3.77 3.49 3.25 3.04 2.86
Tc = time in minutes. Values may exceed 60.
Preci . file name: S:\PROJECTS\CR16\DRNG\CR16-Civil 3D H droflow Rainfall Data. c
Rainfall Precipitation Table (in)
Storm
Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
SCS 24-hour 0.00 1.78 0.00 2.28 4.25 5.77 6.80 4.63
SCS 6-Hr 0.00 1.23 0.00 1.61 2.60 0.00 0.00 3.76
Huff-1st 0.00 0.00 0.00 0.00 4.00 5.38 6.50 0.00
Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Custom 0.00 0.00 0.00 0.00 3.90 5.25 6.00 0.00
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
Figure 3.4-1. Rainfall IDF Curve — Fort Collins
io.oa - _ _
i— 100-Year Storm I
9�� I — — I �—=3D=YearSform I
� I--- 2-Year Storm i I i
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�
— ��, ����_�����,.��f�T
— -- � �—._,-._._._._._._ . I— i
� I— — —r+j ����� �
0.00 — -- --- —
0 10 20 30 40 50 60 70 80 90 100 110 120
Storm Duration (minutes)
c�tyof 3.4 Intensity-Duration-Frequency Curves for Rational Method
�,�O�rtf Page 9
Appendix B
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
UD-Oetention. Ve�slon 3.07 (February 201])
Pralect: t63Timberline
Basin ID: �etention Pantl i-Inclutles Baslns t antl 2
.o �.1.� z � � - �,o _
o,� �,A�E
ap°` ExampleZoneConfiguration�RetentionPond)
Requiretl Volume Calculation
selec�eaBMviype= EDB
WatersM1edqrea= 0.99 es
WalurshedLenylh= 1Ic
Wate�shed5lopo= 0'066
waie,sneam,w���o�s�os:= szoo-�e ue�oam
PeecenlayeHytlrologicSoiiGrouVA= O.ON enl
PorcenlageHydrologlc9oiYGeoupB= 100.0% enl
PeiconlagoHydrolagic9oii6i�oopsC/�= 0.0% onl
Desirod W�CV Drain Time= 40.0 hours
Localion lo� t-hr Ralnlall �eplM1s = Denver -Capiloi 8uil�ing
Wele�QualftyGayWroVoiurzie(WOCV)= 0.018 cre�oel
ExcessUrbanRunof[Vol�ma(EIJR�= wea
2-y� Runofi Voi�ma (P1= 0.8i in.) = OD36 craleel
5-yeRunoilVoiumo(P1=t.�5inJ= 0.052 nae
10ye Runaff Volume (Pt = t.951n.) = 0.013 cm-fvel
25y� Runa11 Vo�ume (P� =1.96'inJ= c ea
SOry� Runo11 Volvnie (P1= 2.43 in.) = O.i5�1 cre-leel
100.ye Runoil Voiume (P1 = 2.9> in.) = 0.188 e� eo
500.ye Runall Volunie (P1 =9.S In.) = 0323 cm-leel
Hpp�oximate2y��etenlionVolume= 0.034 c o0
ApproxlmeteSyrDetenllonVolume= OD48 re-leal
Appeoximale 10�y� Datonllon Volume= OD66 c ae
Apyroximale2Sy�DelenlioiiVolumo= 0.06] cro{oel
Hpp�oximate50-yr�etenlionVolume= c e�
Approxlmete 100.yr �etentloii Volume= 0.120 e leel
�
�
�
�
�
�
�
StageSmraqe Calculation
Zono 1 Vdumu �tW-year)= 0.120 ��e{ee� WOCV not provitletl�
Salecl2une251oraBeVoi�mo(OV��onai)= p ee
Salecl2ane 33�orapa Vdume (Oplionei)= cre-iee�
TotalO�tonlionBesinVolume= O.t20 �e-fee�
InI11ei 5urchar8e Volume (19� _
Inilial9u�charg¢ DopIM1 (ISD) _
To�alNvalebie0e�en�lonOep�M1M;.�i,J= k
oaom olre�v�io cex�n�oi M,J= n
5lopeotTricqeehennel(5„)= Nn
Siopeso(MelnBeslnSiCes(Sm.�,J� H;V
e�m ���n-��-wa�n aera fa,rw> _
Ini�ielSu�cM1aryeqree(Nisv�= fl"2
urcharye VW�me Lengt� (Li����=
SurcM1arge,VolumeWitltM1�Wi��.1= k
oPpmoreasmFloo�(H.,,„p1= n
Lenqih of Basin lioor (L.��mv�= fl
WI�I�hoiBasinFloor(W�i�nl= tt
preaofBasinFloor(F�.�,..�a�= ry^2
ValumaofBeslnFloor(V�«.,�p�= R"3
pep�FofMalnBasin(Hmnin�= (t
1en91h of Maln Besln (Lmnix�=
w��nn or Nlem easm IwMqi,1=
PreaofMainBesin(pmnixl= ��"2
Volume o(Main Besin (V.ni�1=
Cakulated Toial Basin Voluma Nu��n�= e/eet
oe ,��„��ema���
S�a9e-Stor Stag Leng(h Widt� qre Fre Vo�u Vnlu
Desc�p�ion9e (fi) �eln) ((() ((() (ti^2 ea ln�"2) (aore) (n^�)P (ac�n)
Top af Micrapaal 0 000
0.50 484
- 1.00 181J 0.042 6'!1 0016
1 a0 2,260 OA52 1 fi9fi 0.039
2.00 .065 2,9>2
2.50 5.449 0.125 50)3 0.i�i6
3.00 6,15t O.i55 .t9fi
3.50 823t .199 t19fi9 02]2
4.00 _ — — 9.]52 03>6
UD-0e9entlo2v3 0].rism. Besin N2112o21, 1'4'I PM
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
UD-Oetention, Verslon 3.07 (February 2017)
�
E
; ;c
G
y
,.co �e �, a.w
—�e �n�.n —�_a���n A,��.4��i
*�
uo-oe�emm2�a oz.�sm, ea:�� azvzazt na� vm
Detention Basin Outlet Structure Design
UD-Detention, Version 3.07 (Fe6ruary 2017)
Project: 142 Timberline
Basin 1�: Detention Pond t- Includes Basins t and 2
- �20N OHZONEt ._
��,� = Stage (ft) Zone Voiume (arft) Outlet Type
VOWME FURV - - '��-
� -
Iw°°Y. ...-�.�.. � ione1�100-year) 2.54 0.120 circularorifice
zorveinnoz aamce
2one 2
acnMnxEx,-.- oniFicEs Zone3
voo� Example Zone Configuration (Retention Pond)
0.12o Total
User Input: Orifice at Underdrain Outlet (rypically used to drain WQN in a Filtration BMP) Calculated Parameters for Underdrain
Underdrain Orifice Invert Depth = N/A ft(distance below the filtration media surface) Underdrain Orifice Area = N/A ft'
UnderdrainOrificeDiameter= N/A inches UnderdrainOrificeCentroid= N/A feet
User Input Orifice Piate with one or mare orifires or Elliptical Sbt Weir (typicaily used to drain WQCV and/or EURV in a sedimentation BMP) Catculated Parameters for Piate
Invert of Lowest Orifice = N/A ft(relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = N/A ft�
Depth attop of 2one using Orifice Plate = N/A ft(relative to basin bottom at Stage = Oft� Elliptical Half-Width = N/A feet
OrificePlate:OrificeVertical5pacing= N/A inches Elliptical5lotCentroid= N/A feet
OrificePiate:OrificeAreaperRow= N/A inches Elliptical5lotArea= N/A ft'
User Input: Stage and Total Area oF Each orifice Row
Slage of Orifice Centroid
Orifice Area (sq. inch
from lowest to
Row 9(optional) Row 70 (optional) Row 17 (optional) Row 72 (optional) Row 13 (optional) Row 14 (optional) Row 75 (optionalj Row i6 (optional)
Stage of Orifice Centroitl (ft) N/A N/A N/A N/A NIA N/A N/A N/A
Orifice Area (sq.inches) N/A N/A N/A N/A N/A N/A N/A N/A
USerinput: Vertica�Oritice(CirtularorRectanguiar)
Zone 1 Circular Not Se�ected
Imert of Vertical Orifice = 0.00 k Qelative to basin bottom at Stage = 0 ft)
Depth at top of Zone using Vertical Orifice = 2.54 ft(relative to basin bottom at Stage = 0 ft)
Vertical Orifice Diameter = inches
Calcula[ed Parameters for Vertital Otifice
Zone 1 Circular Not Selected
Vertical Orifice Area = gz
Vertical Orifice Centroid = feet
User input: Overflow Weir (Dropbox) and Grate (Flat or5loped) Caiculated Parometers for Overtlow Weir
Not Selected Not Selected Not Selected Not Selected
Overflow Weir Pront Edge Height, Ho = ft �relative to basin bottom at Stage = o ft) Height of Grate Upper Edge, H� = feet
Overflow Weir Front Edge Length = teei Over Plow Weir Slope Length = feet
OverfiowWeirSiope= H:V�enterzeroforflatgrate) GrateOpenArea/100-yrOrificeArea= shouldbe>4
Horiz. Length of Weir Sides = feet Overflow Grate Open Area w/o Debris = g�
Overflow Grate Open Area %_ %, grate open area/total area Overfiow Grate Open Area w/ Debris = ft�
Debris Cloggfng % _ %
USer Input Outiet Pipe w/ Fiow Restricti0n Plate (Circular Oritice, ReStrictor Plate, or Rectangular OrifiCe) Caiculated Parameters for Outlet Pipe w/ Flow Restriction Plate
No[Selened NotSelected NotSelected NotSelected
Depth to Invert of Outlet Pipe = ft �distance below basin bottom at Stage = 0 R) Outlet Orifice Area = {Yz
Circular Orifice Diameter = inches Outlet Orifice Centroid = feet
Half-Central Angle of Restricmr Piate on Pipe= N/A N/A radians
User Input: Emergency Spiliway (Rettangular or Trapezoidal)
Spillway Invert Stage= 2.60 ft (relative to basin bottom at Stage = 0 ft�
Spillway Crest Length = 2.00 feet
Spiliway End Slopes = 4.00 N:V
FreeboardaboveMazWaterSurface= 1.00 feet
Routed Hydrograph Resuits
Design Storm Return Period = WQCV EURV 2 Year S Year 10 Year 25 Year SO Year 100 Year 500 Year
One-Hour Rainfall Depth (in) = 0.53 1.07 0.87 1.15 1.45 1.96 2.43 2.97 450
Calculatetl Runoff Volume (acre-ft) = 0.019 0.061 0.036 0.052 0.073 0116 0.151 0.198 0323
OPTIONAL Override Runoff Volume (acre-ft) _
Inflow Hydrog�aph Volume (acre-ft) = 0.019 0.061 0.035 0.057 0.073 0.116 0.151 0.197 0.323
Predevelopment Unit Peak Flow, q(cfs/acre) = 0.00 0.00 OAS OA2 026 0.95 7.45 2.09 3J3
Predevelopment Peak Q(cfs) = 0.0 0.0 0.0 0.0 0.3 0.9 1.4 2.1 3.7
Peak Inflow Q(cfs) = OS 1.6 0.9 13 1.9 3.0 3.9 5.0 8.2
Peak Outflow Q(cfs) = 01 1.0 3J
Ratio Peak Outflow to Predevelopment Q= 0.7 0.5 1.0
StrucWre Controlling Flow = Spillway Spillway Spiliway
Max Velocity through Grate 1(fps) = N/A N/A N/A
Max Velocity thmugh Grate 2(fps) = N/A N/A N/A
Time to Drain 97 % of Inflow Volume (hours) _ >120 >120 >120
Time to Drain 99 % ot Inflow Volume (hours) _ >120 >120 >120
Maximum Pontling Depth (ft) = 2.70 2.84 3.09
Area at Maximum Ponding Depth (acres) = 014 015 016
Maximum Volume Stored (acre-ft) = 0.141 0.162 0.201
Calculated Parameters for Spillway
Spillway Design Flow Depth= 0.57 feet
Stage at Top of Freeboard = 4.11 teet
BasinAreaatTopofFreeboard= 0.22 aaes
Detention Basin Outlet Structure Design
UD-Detention, Version 3.07 (February 2017�
s
�OUYRIN
�OUYR OUf
8 � SOUYRIN . . . . . . . . . . . . . .
. � — lOUYR OUT
�SOYRIN I I I I
� — — SOYROUi �� �.
I� 25YRIN � — '.. . ..
25YR OUT
6
� lOYR IN � . �. - -
I._
� lOYROUT �II I
N 5 ... —SYRIN . —. . . —
� ...... SYR OUT . . . . . � � I
O . 2YR IN _', . . . � . . .
i .: .: .:. .i.
LL ¢ .. 2vROVi - �
EURV IN , . I „ „ ,,, , I
� EURV OUT � _ . f -
3 ' —w¢cviry ' -' I
: j •
� ...... w¢cv ou1 � , � : � —
Z . — .. .. �1/ .�:... . .. �..
�
_-_a:__ � . ° i i
- � •.
1 - �,._... . '.., _ ..—.—. �._ .
� ' O
p�. _.........e......_._ ................_..!..._..-..... , � �T-.
0.1 • 1 SO
TIME [hr]
3.5 I�SOOYR
—100YH
�
—SOYN
3 .. —. ..--'—"—. . . , .---
25YR
IOYN
�SYR
2.5 �� 2VR - � . . , . . . . —
eurev �
�wqN
C
iZ . . — _.—..—
� � ,.
2 ,"
01.5- . �"-�. _ _ . . . . .
0.5
0
0.1
1
DRAIN TIME [hr]
18,000
16,000
14,000 -
12,000
;K 10,000
F
�
o s,000
>
� 6,000 -
a
¢
4,000
2,000
0
0.00 0.50 1.00 1.50 2.00 250
PONDING DEPTH (ftj
S-A-V-D Chart AUcis Override X-axis Left Y-Axis Right Y-Axis
minimum bound
maximum bound
10
3.00 3.50 4.00
300
35.00
30.00
25.00
20.00 w
3
0
is.00 �
0
10.00
5.00
0.00
450
Detention Pond 1 Stage-Storage Rating
Project: 142 Timberline
Basin Description: Detention Pond 1
Contour Contour Depth
Elevation Area (ft)
(sq. ft)
4,934.00
4,934.50
4,935.00
4,935.50
4,936.00
4,936.50
4,937.00
4,937.50
4,938.00
0.00
484.43
1,813.65
2,279.61
2,844.42
5,448.49
6,750.76
8,231.33
9,751.73
.
. .
. .
o .
o .
o .
. .
o .
Incremental
Volume
Conic
(cu. ft.)
N/A
80.74
539.24
1021.10
1278.41
2038.27
3044.00
3739.41
4490.40
Cumulative
Volume
Conic
(cu. ft.)
0.00
80.74
619.97
1641.07
2919.48
4957.75
8001.76
11741.17
16231.57
100 Year
This is to convert % imp. to a C value
100-year (must insert % imp. and C pervious).
'C' value � 0.57�(2 yr)
'C' 1.25 0.7125 (100 yr)
Area 0.99 acres
Release Rate 0.2
DETENTION POND SIZING
TIME TIME INTENSITY
cum 100 year
(mins) (secs) (in/hr)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
OI
300j
6001
900I
1200 I
15�
1800I
2100 I
2400I
2700
3000
3300
3600
3900
4200
4500
4800
5100
5400
5700
6000
6300i
6600
6900
7200
0
9.950
7.720
6.520
5.600
4.980
4.520
4.080
3.740
3.460
3.230
3.030
2.860
2.720
2.590
2.480
2.380
2.290
2.210
2.130
2.060
2.000
1.940
1.890
1.840
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
220
225
230
235
240
7800
8100
8400
8700
9000
9300
9600�I
9900i
10200
10500
10800
11100
11400i
11700I
12000I
12300
12600
12900I
13200I
13500I
13800
14100
14400
1.750
1.710
1.670
1.630
1.600
1.570
1.540
1.510
1.480
1.450
1.420
1.400
1.380
1.360
1.340
1.320
1.300
1.280
1.260
1.240
1.220
1.210
1.200
e ��
(cfs)
0.00
7.02
5.45
4.60
3.95
3.51
3.19
2.88
2.64
2.44
2.28
2.14
2.02
1.92
1.83
1.75
1.68
1.62
1.56
1.50
1.45
1.41
1.37
1.33
1.30
1.23
1.21
1.18
1.15
1.13
1.11
1.09
1.07
1.04
1.02
1.00
0.99
0.97
0.96
0.95
0.93
0.92
0.90
0.89
0.87
0.86
0.85
0.85
Required detention
ft3 acre-ft.
Modified Modified
M. FATER D. JUDISF C. LI
5/95 Nov-97 Nov-98
Runoff Release Required Required
Volume Cum total Detention Detention
(ft^3) (ft^3) (ft^3) (ac-ft)
0
2105.544j
3267.297j
4139.141 I
4740.12
5269.151
5738.931
6043.653
6331.446
6589.613
6835.084
7053.045
7262.541
7482.618
7673.069
7871.985
8058.204
8238.075
8417.945
8563.958
8718.435
8887.725
9031.622
9198.795
9344.808
9628.369
9770.149
9895.001
10002.92
10157.4
10299.18
10428.26
10544.65
10648.34
10739.33
10817.63
10961.53
11096.96
11223.93
11342.43
11452.47
11554.04
11647.15
11731.8
11807.98
11875.69
12034.4
12188.88
0.0
60.0
120.0
180.0
240.0
300.0
360.0
420.0
480.0
540.0
600.0
660.0
720.0
780.0
840.0
900.0
960.0
1020.0
1080.0
1140.0
1200.0
1260.0
1320.0
1380.0
1440.0
0.0
2045.5
3147.3
3959.1
4500.1
4969.2
5378.9
5623.7
5851.4
6049.6
6235.1
6393.0
6542.5
6702.6
6833.1
6972.0
7098.2
7218.1
7337.9
7424.0
7518.4
7627.7
7711.6
7818.8
7904.8
0.0000
0.0470
0.0723
0.0909
0.1033
0.1141
0.1235
0.1291
0.1343
0.1389
0.1431
0.1468
0.1502
0.1539
0.1569
0.1601
0.1630
0.1657
0.1685
0.1704
0.1726
0.1751
0.1770
0.1795
0.1815
1560.0
1620.0
1680.0
1740.0
1800.0
1860.0
1920.0
1980.0
2040.0
2100.0
2160.0
2220.0
2280.0
2340.0
2400.0
2460.0
2520.0
2580.0
2640.0
2700.0
2760.0
2820.0
2580.0
8068.4
8150.1
8215.0
8262.9
8357.4
8439.2
8508.3
8564.7
8608.3
8639.3
8657.6
8741.5
8817.0
8883.9
8942.4
8992.5
9034.0
9067.2
9091.8
9108.0
9115.7
9214.4
9308.9
0.1852
0.1871
0.1886
0.1897
0.1919
0.1937
0.1953
0.1966
0.1976
0.1983
0.1988
0.2007
0.2024
0.2039
0.2053
0.2064
0.2074
0.2082
0.2087
0.2091
0.2093
0.2115
0.2137
Page 1
Hydrograph Report
Hydraflow Hydrographs Extension for AutodeskOO Civil 3DOO by Autodesk, Inc. v2020
Hyd. No. 3
Basins 1-2
Hydrograph type = Combine
Storm frequency = 100 yrs
Time interval = 1 min
Inflow hyds. = 1, 2
Q (cfs)
7.00
. ��
5.00
� ��
3.00
2.00
1.00
.rT.n
Wednesday, 04 / 21 / 2021
Peak discharge = 6.714 cfs
Time to peak = 5 min
Hyd. volume = 2,829 cuft
Contrib. drain. area = 0.990 ac
Basins 1-2
Hyd. No. 3-- 100 Year
Q (cfs)
7.00
. ��
5.00
4.00
3.00
2.00
1.00
s
0 2 4 6 8 10 12
Hyd No. 3 Hyd No. 1 Hyd No. 2
14 16
18
Time (min)
Hydrograph Report
Hydraflow Hydrographs Extension for AutodeskOO Civil 3DOO by Autodesk, Inc. v2020
Hyd. No. 4
Pond 1 Routing
Hydrograph type = Reservoir
Storm frequency = 100 yrs
Time interval = 1 min
Inflow hyd. No. = 3- Basins 1-2
Reservoir name = Pond 1
Storage Indication method used.
Q (cfs)
7.00
. ��
5.00
� ��
3.00
2.00
1.00
.rT.n
Peak discharge
Time to peak
Hyd. volume
Max. Elevation
Max. Storage
Pond 1 Routing
Hyd. No. 4-- 100 Year
Wednesday, 04 / 21 / 2021
= 0.179 cfs
= 16 min
= 2,828 cuft
= 4935.91 ft
= 2,682 cuft
�,j
��
li
�
��
�
iUl' �
iu
I'ill
liliii
�I�il;�ii��
�p���VV
fl
II!I
Q (cfs)
7.00
. ��
5.00
4.00
3.00
Z.00
1.00
s
0 60
Hyd No. 4
120 180 240 300 360
Hyd No. 3 � � � Total storage used = 2,682 cuft
420
Time (min)
Pond Report
Hydraflow Hydrographs Extension forAutodeskOO Civil 3DOO byAutodesk, Inc. v2020
Pond No. 1- Pond 1
Pond Data
Pond storage is based on user-defined values.
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft)
0.00 4934.00 n/a 0
0.50 4934.50 n/a 81
1.00 4935.00 n/a 539
1.50 4935.50 n/a 1,021
2.00 4936.00 n/a 1,278
2.50 4936.50 n/a 2,038
3.00 4937.00 n/a 3,044
3.50 4937.50 n/a 3,739
4.00 4938.00 n/a 4,490
Culvert / Orifice Structures
[A]
Rise (in) = 2.25
Span (in) = 2.25
No. Barrels = 1
Invert EI. (ft) = 4934.00
Length (ft) = 0.00
Slope (%) = 0.00
N-Value = .013
IBl
0.00
0.00
0
0.00
0.00
0.00
.013
[c�
0.00
0.00
0
0.00
0.00
0.00
.013
[PrFRsr]
0.00
0.00
0
0.00
0.00
n/a
n/a
Weir Structures
Crest Len (ft)
Crest EI. (ft)
Weir Coeff.
Weir Type
Multi-Stage
Wednesday, 04 / 21 / 2021
Total storage (cuft)
0
81
620
1,641
2,919
4,958
8, 002
11,741
16,232
IAl IBl
= 10.00 0.00
= 4937.50 0.00
= 2.60 3.33
= Broad ---
= No No
I�l
0.00
0.00
3.33
No
[D]
0.00
0.00
3.33
No
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000 (by Wet area)
Multi-Stage = n/a No No No TVV Elev. (ft) = 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage / Storage / Discharge Table
Stage Storage Elevation Civ A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 4934.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000
0.50 81 4934.50 0.08 ic --- --- --- 0.00 --- --- --- --- --- 0.085
1.00 620 4935.00 0.13 ic --- 0.00 --- --- --- --- --- 0.127
1.50 1,641 4935.50 0.16 ic --- 0.00 --- --- --- --- --- 0.158
2.00 2,919 4936.00 0.18 ic --- --- --- 0.00 --- --- --- --- --- 0.184
2.50 4,958 4936.50 0.21 ic --- 0.00 --- --- --- --- --- 0.206
3.00 8,002 4937.00 0.23 ic --- 0.00 --- --- --- --- --- 0.227
3.50 11,741 4937.50 0.25 ic --- --- --- 0.00 --- --- --- --- --- 0.245
4.00 16,232 4938.00 0.26 ic --- --- --- 9.19 --- --- --- --- --- 9.455
Weir Report
Hydraflow Express Extension for AutodeskOO Civil 3DOO by Autodesk, �nc.
Detention Pond 1- Emergency Overflow Weir - Q100= 6.8 cfs
Trapezoidal Weir Highlighted
Crest = Sharp Depth (ft)
Bottom Length (ft) = 10.00 Q (cfs)
Total Depth (ft) = 0.50 Area (sqft)
Side Slope (z:1) = 4.00 Velocity (ft/s)
Top Width (ft)
Calculations
Weir Coeff. Cw = 3.10
Compute by: Known Q
Known Q (cfs) = 7.10
Depth (ft)
1.00
0.50
� ��
-0.50
Detention Pond 1- Emergency Overflow Weir - Q100= 6.8 cfs
Thursday, Mar 25 2021
= 0.35
= 7.100
= 3.99
= 1.78
= 12.80
v
Depth (ft)
1.00
0.50
� ��
-0.50
0 2 4 6 8 10 12 14 16 18
Weir w.S. Length (ft)
Stormwater Detention and Infiltration Design Data Sheet
Stormwater Facility Name: Pond 1
Facility Location & Jurisdiction: N. Timberline Road and International Boulevard, Fort Collins, Colorado
User Input: Watershed Charecteristics
Watershed Slope = 0.044 ft/ft
Watershed Length = 181 ft
Watershed Area = 0.99 acres
Watershedlmperviousness= 57.0% percent
Percentage Hydrologic Soil Group A= percent
Percentage Hydrologic Soil Group B= 100.0% percent
Percentage Hydrologic Soil Groups C/D = percent
Location for 1-hr Rainfall Depths (use dropdown):
User Input �
WQCV Treatment Method =I N/n
After completing and printing this worksheet to a pdf, go to:
https://maperture.d iaitaldataservices.com/Rvh/?viewer=cswdif
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Routed H�
Design Storm Return Period = WqCV
One-Hour Rainfall Depth = 0.53
Calculated Runoff Volume =
OPTIONAL Override Runoff Volume =
Inflow Hydrograph Volume =
Time to Drain 97% of Inflow Volume =
Time to Drain 99% of Inflow Volume =
Maximum Ponding Depth =
Maximum Ponded Area =
Maximum Volume Stored =
User Defined User Defined User Defined User Defined
Stage [ftJ Area [ft^2] Stage [ft) Oischarge [cfs]
0.00 0 0.00 0.00
0.50 484 0.50 0.09
1.00 1,814 1.00 0.13
1.50 2,280 1.50 0.16
2.00 2,844 2.00 0.18
2.50 5,449 2.50 0.21
3.00 6,751 3.00 0.23
3.50 8,231 3.50 0.25
4.00 9,752 4.00 9.46
h Results
2 Year 5 Year
0.85 1.12
0.036 0.050
0.035 0.049
3.7 4.6
3.9 4.9
1.21 1.46
0.05 0.05
0.025 0.037
10 Year 50 Year
1.41 234
0.071 0.145
0.071 0.145
6.1 10.1
6.3 10.6
1.81 2.57
0.06 0.13
0.057 0.125
100 Year
2.84
0.189
0.188
123
12.8
2.87
0.15
0.166
SDI_Design_Data_v1.08.xlsm, Design Data 4/21/2021, 12:38 PM
Stormwater Detention and Infiltration Design Data Sheet
6
5
4
u
33
0
LL
Z
1
)0
SDI_Design_Data_v1.08.xlsm, Design Data 4/21/2021, 12:38 PM
Q�� . .-.. .«_,�_axav�ar�.._ i i , � '.
0.1 TIMH [hr] 10
Appendix C
Design Procedure Form: BMP Selection Tool
UD-BMP (Version 3.07, March 2018) Sheet 1 of 1
Designer: Mary B. Wohnrade, P.E.
Company: Wohnrade Civil Engineers, Inc.
Date: September 10, 2020
Project: Timberline-International
Location: Timberline Road, Fort Collins, CO
1. To identify potential BMPs, what best describes Choose ne
the type of site? OO Conventional Site
O Highly Urbanized Site SKIP # 2
� Linear Construction in Urbanized Area
Choose ne
O YES
O NO
3. Is the site comprised of Hydrologic Soil Group A or B sails? Choose ne
OO YES
O NO
4. Is the tributary impervious area' greater than 1 acre? O�ES ne
SKIP #6-10
OO NO
5. Is the depth of bedrock greater than 5 feet? Choose ne
OO YES
O NO
Choose ne
O YES
O NO
Chaose ne
O YES
O NO
Choose ne
O YES
O NO
Choose ne
O YES
O NO
Choose ne
O YES
O NO
11. Step 1 of Four Step Process: Grass Buffer
MDCIA / Volume Reduction (Not WQCV) BMPs Grass Swale
Permeable Pavement- Full Infiltration (5)
Green Roof (3)
12. Step 2 of Four Step Process: Permeable Pavement- Full Infiltration (5)
WQCV BMPs Bioretention- Full Infiltration (5)
Sand Filter Extended Detentio� Basin• Full Infiitration (5)
Green Roof (3)
Regional Water Quality Treatment (4)
Notes: 1. 'Tributar im ervious area' refers to the im ervious area drainin to the BMP, not the total area of the ro'ect site.
2. For a successful wetland channel or basin, a water source roundwater or baseflow will be re uired.
3. In the Front Ran e of Colorado, irr ation, at least eriodicall in dr times, will be re uired to sustain a reen roof.
4. If a re ional facilit will be used to rovide the WQCV. some de ree of onsite treatmenUMDCIA will still Iikel be re uired.
5. No Infiltration= underdrain and liner, Partial Infiltration= underdrain and no liner, Full Infiltration= no underdrain and no liner.
6. Consider this BMP for a ortion of our site. IYs best suited for im ervious tributar areas of a roximatel one acre or less.
TIM_UD-BMP_v3.07_SELECTION_TOOL.xlsm, BMP Selection Tool 9/10/2020, 6:03 PM
Design Procedure Form: Rain Garden (RG)
UD-BMP (Version 3.07, March 2018) Sheet 1 of 2
Designer: Mary B. Wohnrade, P.E.
Company: Wohnrade Civil Engineers, Inc.
Date: February 15,2021
Project: Timberline-International - Rain Garden No. 1
Location: Fort Collins, Colorado
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, la la = 70.0 %
(100 % if all paved and roofed areas upstream of rain garden)
B) Tributary Area's imperviousness Ratio (i = I�/100) i= 0.700
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.22 watershed inches
(WQCV= 0.8 *(0.91 * i3- 1.19 * iZ+ 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 3q933 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWo�� =�cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of ds = 0.35 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQcv orHeR = 462 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User input of Water Quality Capture Volume (WQCV) Design Volume VWocv usEa =� cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWo�� =�9 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z= 4.00 ft / ft
(Use "0" if rain garden has verticai walls)
C) Mimimum Flat Surtace Area AM;� = 433 sq ft
D) Actual Flat Surface Area AA�„ai = 2163 sq ft
E) Area at Design Depth (Top Surtace Area) AroP = 3188 sq ft
F) Rain Garden Total Volume VT= 2,033 cu ft
iVr= iiAroo + Anoma�) / 2) ` Depth)
3. Growing Media Choose ne
OO 18" Rain Garden Growing Media
O Other (Explain):
4. Underdrain System
Choose ne
O YES
A) Are underdrains provided?
O NO
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y= 1.5 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Voli2= 462 cu ft
iii) Orifice Diameter, 3/8" Minimum Do = 1/2 in
UD-BMP_v3.07-Rain_Garden.xlsm; RG 2/15/2021, 5:16 PM
Design Procedure Form: Rain Garden (RG)
sneet 2 or z
Designer: Mary B. Wohnrade, P.E.
Company: Wohnrade Civil Engineers, Inc.
Date: February 15,2021
Project: Timberline-International - Rain Garden No. 1
Location: Fort Collins, Colorado
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric Choose ne
O YES
A) Is an impermeable liner provided due to proximity O NO
of structures or groundwater contamination?
6. Inlet / Outlet Control j� Choose oe
O Sheet Flow- No Energy Dissipation Required
A) Intet Control O Concentrated Flow- Energy Dissipation Provided
Choose oe
7. Vegetation O Seed (Plan for frequent weed controi)
O Plantings
G Sand 6rown or Other Hi9h Infiltration Sod
8. Irrigation Choose ne
O YES
A) Wili the rain garden be irrigated? OO NO
Notes:
UD-BMP_v3.07-Rain_Garden.xlsm; RG 2/15/2021, 5:16 PM
Appendix D
Culvert Report
Hydraflow Express Extension for AutodeskOO AutoCAD RO Civil 3DOO by Autodesk, Inc.
Future Storm Sewer Line
Invert Elev Dn (ft) = 4923.48
Pipe Length (ft) = 392.47
Slope (%) = 0.40
Invert Elev Up (ft) = 4925.05
Rise (in) = 30.0
Shape = Circular
Span (in) = 30.0
No. Barrels = 1
n-Value = 0.013
Culvert Type = Circular Concrete
Culvert Entrance = Square edge w/headwall (C)
Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5
Embankment
Top Elevation (ft) = 4941.89
Top Width (ft) = 24.00
Crest Width (ft) = 100.00
Fu[ure Storm Sewer Line
Calculations
Qmin (cfs)
Qmax (cfs)
Tailwater Elev (ft)
Highlighted
Qtotal (cfs)
Qpipe (cfs)
Qovertop (cfs)
Veloc Dn (ft/s)
Veloc Up (ft/s)
HGL Dn (ft)
HGL Up (ft)
Hw Elev (ft)
Hw/D (ft)
Flow Regime
Tuesday, Aug 7 2018
= 0.00
= 23.00
= Normal
= 23.00
= 23.00
= 0.00
= 5.97
= 6.78
= 4925.31
= 4926.68
= 4927.61
= 1.02
= Inlet Control
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