HomeMy WebLinkAboutReports - Drainage - 08/20/2025PRELIMINARY DRAINAGE REPORT
FOR
Front Range RV and Boat Storage
Prepared For:
Freedom Homes, LLC
4920 Saddlewood Circle.
Johnstown, Colorado 80534
Eric Kelley
(970) 405-3961
August 20th, 2025
Project No. 39817.00
Prepared By:
JR Engineering, LLC
2900 South College Avenue, Suite 1A
Fort Collins, CO 80525
Front Range Storage
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TABLE OF CONTENTS
TABLE OF CONTENTS ......................................................................................................................... ii
APPENDIX ..................................................................................................................................... iii
Engineer’s Certification Block ........................................................................................................... iv
GENERAL DESCRIPTION AND LOCATION ............................................................................................ 7
LOCATION ..................................................................................................................................... 7
DESCRIPTION OF PROPERTY .......................................................................................................... 7
MASTER DRAINAGE BASIN DESCRIPTION ....................................................................................... 7
FLOODPLAIN SUBMITTAL REQUIREMENTS ..................................................................................... 8
DRAINAGE BASINS AND SUB-BASINS ................................................................................................. 9
MAJOR BASINS AND SUB-BASINS ................................................................................................... 9
EXISTING SUB-BASIN DESCRIPTION ................................................................................................ 9
EXISTING OFF-SITE DRAINAGE BASINS ........................................................................................... 9
PROPOSED SUB-BASINS DESCRIPTIONS ....................................................................................... 10
OFF-SITE SUB-BASINS DESCRIPTIONS ........................................................................................... 11
PROJECT DESCRIPTION .................................................................................................................... 11
PROJECT DESCRIPTION ................................................................................................................ 11
PROPOSED DRAINAGE FACILITIES .................................................................................................... 11
GENERAL CONCEPT ..................................................................................................................... 11
WATER QUALITY .......................................................................................................................... 12
LOW IMPACT DEVELOPMENT ...................................................................................................... 12
DRAINAGE DESIGN CRITERIA ........................................................................................................... 13
REGULATIONS ............................................................................................................................. 13
FOUR STEP PROCESS TO PROTECT RECEIVING WATERS ............................................................... 13
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS ........................................................... 14
HYDROLOGIC CRITERIA ................................................................................................................ 15
HYDRAULIC CRITERIA ................................................................................................................... 15
FLOODPLAIN REGULATIONS COMPLIANCE ................................................................................... 15
MODIFICATIONS OF CRITERIA ...................................................................................................... 15
EROSION CONTROL ..................................................................................................................... 16
CONCLUSIONS ................................................................................................................................. 16
COMPLIANCE WITH STANDARDS ................................................................................................. 16
DRAINAGE CONCEPT ................................................................................................................... 16
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APPENDIX
Appendix A – Figures
Appendix B – Hydrologic Calculations
Appendix C – Hydraulic Calculations
Appendix D – Water Quality Calculations
Appendix E – Reference
Appendix F – Maps
Appendix G – LID Exhibit
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Engineer’s Certification Block
I hereby attest that this report for the final drainage design for the Front Range RV Boat and Storage 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.
Joseph Martin Frank, PE
Registered Professional Engineer
State of Colorado No. 53399
For and on behalf of JR Engineering
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GENERAL DESCRIPTION AND LOCATION
LOCATION
The site is located in the North half of the Northwest Quarter and the East Half of Section 3,
Township 7 North, Range 68 West of the 6th Principal Meridian, City of Fort Collins, County of
Larimer, State of Colorado. More specifically, the site is a 105-acre property that is zoned I-
Industrial. The concept plan proposes approximately 12 acres of outdoor, non-covered
recreational vehicle and boat storage. The remaining 95 acres will remain for agricultural use.
The site is situated on the NE Frontage Rd on the West side and is bordered by the Larimer and
Weld County Canal (“LWCC”) on the south side. To the East, the site abuts four presently
vacant parcels of land, while to the north, it borders the land owned by the Colorado Division
of Wildlife.
DESCRIPTION OF PROPERTY
The Front Range Storage area spans approximately 105 acres, with approximately 12 acres
designated for development into RV and boat storage. The remaining 95 acres will continue to
be used as irrigated agricultural land. The site currently features an existing gravel road access
located just off the NE Frontage Road. Most of the site remains undeveloped and is presently
being utilized for agriculture and a U-Haul rental service. Two buildings are the only existing
structures on site, situated just east of the Frontage Road. Although flow paths are not precisely
defined, the general drainage pattern of the site follows a gradual slope ranging from 1% to 4% in
the northeast to the southwest direction. According to the Natural Resources Conservation
Service (NRCS), approximately half of the soils on the site are composed of type B soils, which
have a mild infiltration and runoff rate. The remaining site is made up of type C soils, which are
characterized by a lower infiltration rate and corresponding higher runoff rates. For additional
information, refer to the NRCS soil map within Appendix A of this report. Adjacent to the
proposed site, a pre-existing 15” corrugated metal pipe facilitates the drainage of any surplus
stormwater and irrigation water from the site into the Larimer and Weld Canal. The existing
culvert is not capable of conveying large quantities of runoff.
MASTER DRAINAGE BASIN DESCRIPTION
The site is positioned within the Boxelder Creek Basin and shares borders with the Upper
Cooper Slough and Lower Cooper Slough basins. The Boxelder Creek watershed and associated
floodplain consists, to a large degree, of mostly undeveloped land. Currently, the site drains
through a 15” CMP and outfalls into the Larimer and Weld Canal. The Larimer and Weld County
Canal (LWCC) policy as of 2025 is not to accept stormwater runoff from any new developments.
To address this policy restriction, a Joint Outfall Channel was designed as a regional drainage
solution to intercept and convey both on-site and off-site stormwater runoff away from the
Larimer and Weld Canal (LWCC). The Joint Outfall Channel Design Report (PEC, June 2025),
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prepared in coordination with Larimer County and the City of Fort Collins, evaluated hydrologic
and hydraulic conditions under various scenarios and confirmed that stormwater from the Front
Range Storage site—as well as runoff from the adjacent Colorado Parks and Wildlife (CPW)
relocation project—will be diverted southeast to discharge directly into Boxelder Creek. This
channel eliminates the historical drainage path to the LWCC and ensures full compliance with
the LWCC policy of prohibiting stormwater discharge from new developments. The design
utilizes a shallow, grass-lined trapezoidal channel with sufficient capacity and freeboard (1 ft) to
safely convey peak flows without impacting downstream flood elevations. Under the adopted
“beat-the-peak” strategy, the timing of runoff discharge avoids coinciding with peak flows in
Boxelder Creek, ensuring no rise in floodplain elevations and maintaining downstream flood
protection.
FLOODPLAIN SUBMITTAL REQUIREMENTS
The Front Range RV Boat and Storage site is on FEMA FIRM panels 08069C0982F and
08069C1001F. The Front Range RV Boat and Storage site lies within FEMA Zone X, areas that
are determined to be outside the 0.2% annual chance floodplain. The Front Range RV Boat and
Storage site is not located within a FEMA-regulated floodplain, as shown in Appendix A in the
FEMA attachments. The site is also not located in the City of Fort Collins Floodplain, as shown
in Appendix A in the City of Fort Collins Flood map.
The site ultimately drains into the Boxelder Creek Floodplain, specifically within the FEMA-
designated Zone AE, which is defined as a special flood hazard area subject to inundation by the
1% annual chance flood (100-year flood), as documented in the Joint Outfall Channel Design Report
prepared by Professional Engineering Consultants (PEC, June 2025). The report confirms that
under the proposed drainage configuration using the joint outfall channel and a “beat-the-peak”
approach, there is no adverse impact to the Base Flood Elevation (BFE), with modeling results
demonstrating no rise—i.e., a change of 0.00 feet—to the hundredth of a foot, thereby satisfying
the no-rise criteria for development within Zone AE.
Outfall to Boxelder Creek is planned to discharge through the FEMA-regulated 100-year
floodplain of Boxelder Creek, including areas both within and outside the Fort Collins city limits.
All required permits and approvals will be obtained from the applicable regulatory authorities
prior to any construction activities within the floodplain.
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DRAINAGE BASINS AND SUB-BASINS
MAJOR BASINS AND SUB-BASINS
The Front Range RV Boat and Storage site is located in the Boxelder Creek Basin. The Upper
and Lower Cooper Slough Basins exist to the west of the site. Covering approximately 265 square
miles, the Boxelder Creek extends from north of the Colorado/Wyoming border and stretches
southward into the eastern part of Fort Collins. These basins are predominantly characterized
by farmland, with occasional pockets of mixed-use residential development and limited
commercial development.
EXISTING SUB-BASIN DESCRIPTION
Basin EO1, 12.51 acres and 8.2% impervious, is composed of the proposed RV Boat and storage
site.
Basin EX2, 36.9 acres and 2% impervious, is composed of the portion of the site east of the
proposed RV Boat and Storage site.
Basin EX3, 19.8 acres and 2% impervious, is composed of the portion of the site east of the
proposed RV Boat and Storage site.
EXISTING OFF-SITE DRAINAGE BASINS
Currently, the site collects off-site runoff from the north, including flow from the Colorado
Division of Wildlife property just north of 1435 NE Frontage Road, which drains onto the site as
sheet flow. This runoff historically discharged directly into the Larimer and Weld Canal.
Additionally, runoff from the eastern off-site basin flows south into the canal. A natural ridgeline
divides portions of the northeast and southeast off-site basins, such that runoff west of the
ridgeline drains into the Larimer and Weld Canal, while runoff east of the ridgeline drains into
Boxelder Creek. During the 100-year storm event, it is anticipated that runoff from the north
and along the NE Frontage Road will sheet flow onto the site. This off-site drainage pattern was
previously modeled in the Boxelder Creek LOMR As-Built SWMM model prepared by Ayres
Associates in 2018. An exhibit showing this model configuration has been provided in Appendix
D of the PEC report.
The Joint Outfall Channel Design Report (PEC, June 2025) builds upon this as-built hydrologic
foundation and incorporates the same modeling framework to evaluate proposed conditions. The
PEC study details both the on-site and off-site runoff release rates and incorporates a "beat-the-
peak" off-site flow management strategy to ensure compliance with FEMA floodplain regulations.
The report confirms that these regional stormwater improvements—including the construction
of the joint outfall channel—will be implemented in advance of the development of the Front
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Range Storage Facility, ensuring that no stormwater from the site discharges into the Larimer
and Weld Canal and that all flows are safely routed to Boxelder Creek without adverse impact.
PROPOSED SUB-BASINS DESCRIPTIONS
Basin C1 is 1.11 acres and 61% impervious. This basin includes access to the site off the I-25
North East Frontage Road. Runoff from this basin is treated in the on-site rain garden. For runoff
greater than the water quality event, flows will overflow into two 30" RCPs.
Basin C2 is 0.89 acres and 74% impervious. This basin consists of the site entrance and access
improvements from the Frontage Road. Runoff drains to the rain garden located in the southern
portion of the site. When the rain garden overtops the overflow weir, flows are conveyed to the
overflow channel.
Basin C3 is 2.03 acres and 78% impervious. This basin is composed of uncovered parking, paved
drive aisles, and some landscaped areas. Runoff is directed to a rain garden at Design Point 3 in
the southern portion of the site. Overflow from the rain garden is conveyed to the overflow
channel.
Basin C4 is 1.08 acres and 79% impervious. This basin includes uncovered parking, paved drive
aisles, and some landscaping. Runoff flows into a rain garden at Design Point 4 in the southern
portion of the site, and then is conveyed to the overflow channel.
Basin C5 is 1.08 acres and 79% impervious. This basin contains uncovered parking and paved
drive aisles. Runoff is directed to a rain garden at Design Point 5 in the southern portion of the
site, where overflow is conveyed to the overflow channel.
Basin C6 is 1.17 acres and 79% impervious. This basin consists of uncovered parking and paved
drive aisles. Runoff is directed to a rain garden at Design Point 6 in the southern portion of the
site, and overflow is conveyed to the overflow channel.
Basin C7 is 0.34 acres and 78% impervious. This basin includes uncovered parking and paved drive
aisles. Runoff is directed to a rain garden at Design Point 7 in the southern portion of the site,
with overflow conveyed to the overflow channel.
Basin C8 is 1.08 acres and 79% impervious. This basin is composed of uncovered parking and
paved drive aisles. Runoff is directed to a rain garden at Design Point 8 in the southern portion
of the site, with overflow conveyed to the overflow channel.
Basin C9 is 0.58 acres and 3% impervious. This basin includes mostly pervious areas with limited
impervious surface. Runoff drains to the rain garden located in the southern portion of the site.
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OFF-SITE SUB-BASINS DESCRIPTIONS
Basin OS1 is 0.26 acres and 100% impervious. This basin is composed of the I-25 North East
Frontage Road and associated impervious improvements.
Basin OS2 is 0.92 acres and 3% impervious. This is composed of Tract B and receives runoff from
basin OS1, where it drains onto the site.
Basin OS3 is 38.11 acres and 2% impervious. This large basin drains to the overflow channel,
which then outfalls to Boxelder Creek by overtopping the weir from the outlet structure.
Basin OS4 is 20.31 acres and 2% impervious. This basin drains to a swale, which then outfalls into
Boxelder Creek.
PROJECT DESCRIPTION
PROJECT DESCRIPTION
The Front Range RV & Boat Storage site is a recreational vehicle and boat storage facility at 1312
NE Frontage Road. The previously undeveloped portion of the 105-acre property, approximately
12 acres, is for outdoor covered and uncovered recreational vehicle and boat storage. The
remaining 95 acres will remain for agricultural use.
PROPOSED DRAINAGE FACILITIES
GENERAL CONCEPT
The proposed development of the Front Range RV & Boat Storage site will result in the developed
condition being fully treated for water quality through on-site rain gardens. No detention is
proposed; instead, the site utilizes a 'beat-the-peak' strategy, as outlined in the Joint Outfall
Channel Design Report prepared by Professional Engineering Consultants (PEC), June 2025, to
release runoff ahead of peak flows in Boxelder Creek and avoid adverse downstream impacts.
Low-impact development best management practices are proposed to improve the quality of
runoff and aid in reducing peak flows. Specifically, a rain garden will be used in the southern
portion of the site to treat runoff and provide water quality for the majority of the site. In the
100-year event, the water quality will overtop and drain into the overflow channel via an overflow
weir. The remaining portion of the site will be treated for water quality up north near the site's
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access from the I-25 Frontage Road and will overtop the rain garden into two 30" culverts in the
100-year event.
WATER QUALITY
The site includes a Rain Garden(s) designed to capture and address 100% of the total water
quality capture volume on the site. The Rain Garden(s) will be maintained to ensure the ongoing
protection of the receiving waters. The property will provide water quality treatment for the
Front Range RV & Boat Storage development and is designed to utilize a “beat-the-peak”
approach, allowing stormwater to be released ahead of the Boxelder Creek peak flow. This
stormwater management strategy is based on the recommendations in the PEC - Joint Outfall
Channel Design Report. Refer to the water quality map in Appendix G for more details.
LOW IMPACT DEVELOPMENT
A minimum of 75% of the new impervious surface area is treated by a Low-Impact Development
(LID) best management practice (BMP) in accordance with City criteria. An illustrative LID/
Surface Map is provided in Appendix G, and the sizing of the LID methods is provided in Appendix
D.
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DRAINAGE DESIGN CRITERIA
REGULATIONS
This report was prepared to meet or exceed the City of Fort Collins stormwater criteria. The
City of Fort Collins Stormwater Criteria Manual (dated 2018)(FCSCM) and the Urban Drainage
Flood Control District’s (UDFCD) Drainage Criteria Manual (USDCM) Volumes 1, 2, and 3 were
referenced as guidelines for this design.
FOUR STEP PROCESS TO PROTECT RECEIVING WATERS
The City of Fort Collins requires the Four Step Process to protect receiving waters. The four-
step process incorporates reducing runoff volume, treating water quality capture volume,
stabilizing streams, and implementing long-term source controls. Volume reduction is an
important part of the Four Step Process and is fundamental to effective stormwater management.
Per City criteria, a minimum of 75 percent of new impervious surface area must be treated by a
Low-Impact Development (LID) best management practice (BMP). The site incorporates two on-
site rain gardens designed to capture and treat 100% of the site's water quality capture volume.
The Rain Gardens need to be properly cleaned and maintained to allow for long-term protection
of the receiving waters. The proposed LID BMPs will have the effect of slowing runoff through
the site lot and increasing infiltration and rainfall interception by encouraging infiltration and
careful selection of vegetative cover. The LID exhibit is shown within Appendix G of this report.
Step 1 – Employ Runoff Reduction Practices
The majority of developed runoff on the site will be routed through Low-Impact Development (LID)
features designed to reduce volume and improve water quality. Specifically, two on-site rain gardens are
provided to capture, infiltrate, and treat 100% of the site's water quality capture volume. These rain
gardens promote infiltration, evapotranspiration, and pollutant removal in accordance with City of Fort
Collins criteria.
No detention is proposed for the site. Instead, the design utilizes a “beat-the-peak” strategy, whereby site
runoff is released ahead of the peak flows in Boxelder Creek. This method ensures that stormwater
discharges do not coincide with peak downstream flows, preventing any rise in floodplain elevations. The
approach is consistent with the findings and recommendations outlined in the Joint Outfall Channel Design
Report prepared by Professional Engineering Consultants (PEC), June 2025, which confirms there will be
no adverse impact to the Boxelder Creek Floodplain.
Step 2 – Implement BMPS that Provides Water Quality Capture Volume
The site incorporates two on-site rain gardens designed to capture and treat 100% of the site's
water quality capture volume. These rain gardens are engineered to provide full water quality
treatment for all on-site impervious areas, ensuring long-term protection of the receiving waters.
Proper maintenance and regular cleaning of the rain gardens will be required to maintain effective
treatment performance. For additional information, see the water quality map in Appendix G of
this report.
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Step three –Stabilize Drainage ways
The stormwater improvements for the Front Range RV Boat and Storage project significantly
enhance the existing drainage conditions by treating stormwater flows through a combination of
Best Management Practices (BMPs). These improvements include the implementation of Low
Impact Development (LID) strategies designed to improve water quality by promoting infiltration,
reducing runoff volume, and filtering pollutants before discharging to downstream receiving
waters.
In support of compliance with floodplain development regulations, a No-Rise study has been
completed by PEC demonstrating that the project does not result in any increase in base flood
elevations within the designated Boxelder Creek floodplain. Additionally, channel improvements
were incorporated to enhance capacity and promote stable conveyance of flows while protecting
downstream infrastructure and natural resources.
Step four – Implement site-specific and other source control BMPs
Water quality for 100% of the site will be treated by two on-site rain gardens. These facilities are
designed to capture and treat all stormwater runoff from the site's impervious areas. An Erosion
Control Plan and Stormwater Management Plan will be implemented to prevent erosion and
control sediment on the project site and in downstream drainageways during and after
construction.
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
The as-built SWMM model from the 2018 Boxelder LOMR was used to determine the existing
runoff through the site. This 2018 as-built SWMM model accounts for improvements
constructed upstream of the site, specifically the East Side Detention Facility. Additionally, the
proposed conditions SWMM model prepared by Professional Engineering Consultants (PEC) in
their attached Joint Outfall Channel Design report was used for analyzing the impacts of the
proposed developments and was built off the 2018 as-built SWMM model to include the
proposed Colorado Parks and Wildlife site and the Front Range RV Boat and Storage site and
future developable area directly east of the RV Boat and Storage site.
The site is designed to discharge directly into Boxelder Creek, utilizing a "beat-the-peak"
method to manage stormwater runoff effectively. This method involves managing runoff timing
so that flows from the development precede the peak flows in Boxelder Creek, thereby
preventing any increase in downstream flood elevations.
A gravel access path to the Larimer and Weld Canal (LWCC) has been provided as part of the
site layout. This access path connects to the existing gravel LWCC maintenance route and is
not anticipated to adversely impact water quality, as it will be stabilized, constructed with
permeable materials, and limited to occasional maintenance use
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JR Engineering designed stormwater management features, including a raingarden, specifically
for water quality purposes, with no detention designed to meet historic release rates, and is
utilizing the "beat the Peak" method as outlined in the Joint Channel Design report by PEC.
The percent impervious values for this site are compliant with those outlined in the "beat-the-
peak" model section of the Joint Outfall Channel Design report prepared by PEC. The adjacent
Colorado Parks and Wildlife (CPW) development to the north is also addressed within the
PEC report, confirming overall compliance and coordinated stormwater management strategy.
The composite percent impervious for the Front Range Self Storage Facility is 66.8% impervious
at 11.02 acres. This number includes the basins OS1 and OS2, which are composed of the open
space landscape buffer for Tract B and the Frontage Road for I-25. The total area and percent
impervious for the Front Range Self Storage site is less than the percent impervious modeled in
the Joint Outfall Channel Design report prepared by PEC, which was modeled as 70%
impervious over a 16.4-acre area (Sub-basin 99.9). Additionally, the PEC report conservatively
evaluates the future industrial development area to the East at 80% impervious, allowing room
for further development.
HYDROLOGIC CRITERIA
Weighted percent imperviousness was calculated for each basin using the Fort Collins Stormwater
Criteria Manual Table 3.2-2. The City of Fort Collins area has rainfall depths associated with the table
below, as shown in Chapter 5 of the Fort Collins Stormwater Criteria Manual.
HYDRAULIC CRITERIA
At the time of the Final Plan (FP), StormCAD will be utilized to determine the hydraulic capacity of the
storm sewer system on site. Additionally, hydraulic calculations for items such as street capacity, swales,
channels, and the emergency spillway will be provided within the Final Drainage Report.
FLOODPLAIN REGULATIONS COMPLIANCE
As previously stated, the Front Range RV and Boat Storage site lies within FEMA Zone X, areas that are
determined to be outside the 0.2% annual chance floodplain. The site is not located within a FEMA-
regulated floodplain, as shown in Appendix A in the FEMA attachments. The site is also not located in the
City of Fort Collins Floodplain, as shown in Appendix A in the City of Fort Collins Flood map.
MODIFICATIONS OF CRITERIA
No new developments are permitted to discharge developed runoff into the Larimer and Weld
Canal. As a result, the only outfall option for the site is Boxelder Creek, located just east of the
property. The composite slope of the swale from the southeast corner of the facility to the
Boxelder Creek outfall is on average 0.16%. The total channel length will be 3,859 lineal feet, with
a fall of 6.1 feet, for an average longitudinal slope of 0.16%. This swale does not include a concrete
trickle pan at the bottom. The open channel swale design will simplify routine maintenance and
will also serve as the future outfall conveyance for the remaining undeveloped portions of the
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site, provided that those areas meet the impervious values and area requirements outlined in the
PEC Joint Outfall Channel Design Report and Study.
The site does not provide on-site detention but is designed to utilize a "beat-the-peak" approach
for stormwater management, in accordance with the City of Fort Collins Stormwater Criteria
Manual, which allows beat-the-peak strategies in specific situations where traditional detention
may increase downstream flood risk. All on-site modified and new impervious areas are fully
treated for water quality through the two on-site rain gardens. This approach significantly
improves upon the existing condition, where much of the runoff was previously untreated, and
ensures enhanced protection of downstream receiving waters. See the LID exhibit in Appendix
G for details.
EROSION CONTROL
A statement of compliance with Erosion Control Criteria and all Erosion Control Materials will be
provided with the Final Drainage Report.
CONCLUSIONS
COMPLIANCE WITH STANDARDS
The hydrologic and water quality calculations were performed using the required methods as
outlined in the City of Fort Collins Storm Water Criteria Manual. The proposed drainage
improvements meet or exceed the City’s requirements except for the parameters presented in
the Modification to Criteria section of this Report.
DRAINAGE CONCEPT
The proposed concept for the RV & Boat Storage site utilizes surface flows and open swales to
convey runoff across the property. All on-site runoff will be treated in rain gardens, while off-site
flows are conveyed through the site. Unlike the historic condition, the site will no longer drain
into the Larimer and Weld County Canal ("LWCC") to the south. Instead, all site and off-site
runoff will be routed to Boxelder Creek to the East. The design employs a "beat-the-peak"
approach, ensuring that stormwater is released ahead of the Boxelder Creek peak. This method
does not increase the total flow into Boxelder Creek, and the proposed improvements will not
adversely impact the flow rate, character, or quality of runoff leaving the site.
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REFERENCES
Fort Collins Stormwater Criteria Manual; City of Fort Collins, Colorado, December 2018.
Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3); Urban Drainage and Flood Control District,
June 2001.
Hydrologic Analysis of the Box Elder Creek/ Cooper Slough Watershed Icon Engineering, Apr. 2014.
Boxelder and Cooper Slough Letter of Map Revision (LOMR) for the Boxelder 6 Project."AYRES &
ASSOCIATES, 5 Nov. 2018.
Joint Outfall Channel Design Report for the Colorado Parks and Wildlife Fort Collins Office Relocation and
Front Range Storage Project.Professional Engineering Consultants (PEC), June 2025.
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APPENDIX A – FIGURES
A Westrian Company
Hydrologic Soil Group—Larimer County Area, Colorado
(Mountain Vista Property)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 1 of 4
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499700 499800 499900 500000 500100 500200 500300 500400 500500 500600 500700 500800 500900 501000
499700 499800 499900 500000 500100 500200 500300 500400 500500 500600 500700 500800 500900 501000
40° 36' 26'' N
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40° 36' 26'' N
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 300 600 1200 1800
Feet
0 50 100 200 300
Meters
Map Scale: 1:6,250 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
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 17, Sep 7, 2022
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.
Hydrologic Soil Group—Larimer County Area, Colorado
(Mountain Vista Property)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
7 Ascalon sandy loam, 0
to 3 percent slopes
B 14.8 14.5%
53 Kim loam, 1 to 3 percent
slopes
B 26.5 25.9%
54 Kim loam, 3 to 5 percent
slopes
B 16.6 16.2%
73 Nunn clay loam, 0 to 1
percent slopes
C 23.8 23.2%
74 Nunn clay loam, 1 to 3
percent slopes
C 10.1 9.9%
94 Satanta loam, 0 to 1
percent slopes
C 0.2 0.2%
95 Satanta loam, 1 to 3
percent slopes
C 10.2 10.0%
105 Table Mountain loam, 0
to 1 percent slopes
B 0.1 0.1%
Totals for Area of Interest 102.4 100.0%
Hydrologic Soil Group—Larimer County Area, Colorado Mountain Vista Property
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 3 of 4
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
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado Mountain Vista Property
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 4 of 4
18,056
3,009.3
FCMaps
This map is a user generated static output from the City of Fort Collins FCMaps
Internet mapping site and is for reference only. Data layers that appear on this
map may or may not be accurate, current, or otherwise reliable.
City of Fort Collins - GIS
2,286.0
1:
WGS_1984_Web_Mercator_Auxiliary_Sphere
Feet2,286.001,143.00
Notes
Legend
13,719
FEMA Floodplain
FEMA High Risk - Floodway
FEMA High Risk - 100 Year
FEMA Moderate Risk - 100 / 500 Year
City Floodplains
City High Risk - Floodway
City High Risk - 100 Year
City Moderate Risk - 100 Year
City Limits
World Hillshade
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mileZone X
Future Conditions 1% Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood HazardZone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 7/21/2023 at 10:33 AM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
B 20.2
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
105°0'6"W 40°36'26"N
104°59'29"W 40°35'58"N
Basemap Imagery Source: USGS National Map 2023
9,028
1,504.7
FCMaps
This map is a user generated static output from the City of Fort Collins FCMaps
Internet mapping site and is for reference only. Data layers that appear on this
map may or may not be accurate, current, or otherwise reliable.
City of Fort Collins - GIS
1,143.0
1:
WGS_1984_Web_Mercator_Auxiliary_Sphere
Feet1,143.00571.50
Notes
Legend
6,859
Street Names
FEMA Floodplain
FEMA High Risk - Floodway
FEMA High Risk - 100 Year
FEMA Moderate Risk - 100 / 500 Year
City Floodplains
City High Risk - Floodway
City High Risk - 100 Year
City Moderate Risk - 100 Year
City Limits
Front Range Storage
Preliminary Drainage Report
19
APPENDIX B – HYDROLOGIC CALCULATIONS
Subdivision:RV & Boat Storage Project Name:Mountain Vista Property
Location:Fort Collins Project No.:
Calculated By:JSC
Checked By:ARJ
Date:1/30/23
EO1 12.51 40%1.88 6.0%90%0.05 0.4%2%10.57 1.7%90%0.02 0.1%8.2%
EX2 36.90 40%0.00 0.0%90%0.00 0.0%2%36.90 2.0%90%0.00 0.0%2.0%
EX3 19.80 40%0.00 0.0%90%0.00 0.0%2%19.80 2.0%90%0.00 0.0%2.0%
TOTAL 49.41 40%1.88 1.5%90%0.05 0.1%2%47.47 1.9%90%0.02 0.0%3.6%
Basins Total
Weighted %
Imp.
Asphalt/Concrete
% Imp.Area (ac)Weighted
% Imp.
COMPOSITE % IMPERVIOUS CALCULATIONS
Weighted
% Imp.Basin ID Total Area (ac) % Imp. Area (ac)
Landscape or Previous Surface
% Imp. Area (ac)Weighted %
Imp.
Gravel Rooftop
Weighted
% Imp.% Imp. Area (ac)
39817.00
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 1/30/2024
UPDATED BASIN ASPHALT/CONCRETE
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 1/30/2024
Subdivision:RV & Boat Storage Project Name:Mountain Vista Property
Location:Fort Collins Project No.:
Calculated By:JSC
Checked By:ARJ
Date:1/30/23
EO1 12.51 0.50 1.88 0.08 0.09 0.95 0.05 0.00 0.00 0.20 10.57 0.17 0.21 0.95 0.02 0.00 0.00 0.17 0.22
EX2 36.90 0.50 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.20 36.90 0.20 0.25 0.95 0.00 0.00 0.00 0.20 0.25
EX3 19.80 0.50 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.20 19.80 0.20 0.25 0.95 0.00 0.00 0.00 0.20 0.25
Basin ID
Basins Total
Weighted 100
YEAR C
COMPOSITE RUNOFF COEFFICIENT CALCULATIONS
Basins Total
Weighted 2
YEAR CArea (ac)2 -
YEAR C
100 -
YEAR C
Runoff
Coefficient Area (ac)2 -
YEAR C
100 -
YEAR C
39817.00
Total Area
(ac)Runoff
Coefficient Area (ac)Area (ac)
Gravel Rooftop Landscape or Previous Surface
Runoff
Coefficient
Asphalt/Concrete
2 -
YEAR C
100 -
YEAR C
2 -
YEAR C
100 -
YEAR C
Runoff
Coefficient
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Subdivision:RV & Boat Storage Project Name:Mountain Vista Property
Location:Fort Collins Project No.:
Calculated By:JSC
Checked By:ARJ
Date:1/30/23
BASIN D.A. Hydrologic Impervious C2 C100 L S o t i - 2 Year t i - 100 Year L t S t K VEL.t t COMP.t c-2 Year COMP.t c 100 - Year TOTAL Tc t i - 2 Year t c- 100 Year
ID (ac) Soils Group (%)(ft)(%)(min)(min)(ft)(%)(ft/s)(min)(min)(min)LENGTH (ft)Check (min)(min)
EO1 12.51 B/C 8%0.17 0.22 100 0.6%93.6 89.2 200 1.0%5.0 0.5 6.7 100.3 95.9 300.0 11.7 12.0 12.0
EX2 36.9 B/C 2%0.20 0.25 100 1.0%76.9 72.7 800 1.8%5.0 0.7 19.9 96.8 92.5 900.0 15.0 15.0 15.0
EX3 19.8 B/C 2%0.20 0.25 100 1.0%76.9 72.7 713 1.0%5.0 0.5 24.0 100.9 96.7 813.0 14.5 15.0 15.0
Notes:
Velocity V = K*St^0.5
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN
39817.00
FINAL(URBANIZED BASINS)
tc CHECK
DATA
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Project Name:Mountain Vista Property
Subdivision:RV & Boat Storage Project No.:
Location:Fort Collins Calculated By:JSC
Design Storm:Checked By:ARJ
Date:
TRAVEL TIME
STREET
De
s
i
g
n
P
o
i
n
t
Ba
s
i
n
I
D
Ar
e
a
(
A
c
)
Ru
n
o
f
f
C
o
e
f
f
.
tc
(
m
i
n
)
-
2
Y
E
A
R
C*
A
(
A
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
tc
(
m
i
n
)
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
Qst
r
e
e
t
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Qpi
p
e
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Pi
p
e
S
i
z
e
(
i
n
c
h
e
s
)
Le
n
g
t
h
(
f
t
)
Ve
l
o
c
i
t
y
(
f
p
s
)
tt
(
m
i
n
)
REMARKS
1 EO1 12.51 0.17 12.0 2.18 2.05 4.5
1 EX2 36.90 0.20 15.0 7.38 1.87 13.8
1.1 12.0 9.56 2.05 19.6
3 EX3 19.80 0.20 15.0 3.96 1.87 7.4
Notes:
Street and Pipe C*A values are determined by Q/I using the catchment's intensity value.
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Project Name:Mountain Vista Property
Subdivision:RV & Boat Storage Project No.:
Location:Fort Collins Calculated By:JSC
Design Storm:Checked By:ARJ
Date:
TRAVEL TIME
STREET
De
s
i
g
n
P
o
i
n
t
Ba
s
i
n
I
D
Ar
e
a
(
a
c
)
Ru
n
o
f
f
C
o
e
f
f
.
tc
(
m
i
n
)
-
1
0
0
Y
e
a
r
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
tc
(
m
i
n
)
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
Qst
r
e
e
t
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Qpi
p
e
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Pi
p
e
S
i
z
e
(
i
n
c
h
e
s
)
Le
n
g
t
h
(
f
t
)
Ve
l
o
c
i
t
y
(
f
p
s
)
tt
(
m
i
n
)
REMARKS
1 EO1 12.51 0.22 12.0 2.73 7.16 19.5
1 EX2 36.90 0.25 15.0 9.23 6.52 60.2
1.1 12.0 11.96 7.16 85.6
3 EX3 19.80 0.25 15.0 4.95 6.52 32.3
Notes:
Street and Pipe C*A values are determined by Q/I using the catchment's intensity value.
STORM DRAINAGE SYSTEM DESIGN
STANDARD FORM SF-3
(RATIONAL METHOD PROCEDURE)
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF
1/30/23
STREET
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:ARJ
Checked By:0
Date:7/28/25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
C1 1.11 100%0.65 58.5%80%0.02 1.5%90%0.00 0.0%2%0.44 0.8%60.7%
C2 0.89 100%0.64 71.6%80%0.00 0.0%90%0.02 2.0%2%0.23 0.5%74.0%
C3 2.03 100%0.00 0.0%80%1.98 77.9%90%0.00 0.0%2%0.05 0.1%78.0%
C4 1.08 100%0.00 0.0%80%1.07 79.0%90%0.00 0.0%2%0.01 0.0%79.0%
C5 1.08 100%0.00 0.0%80%1.06 79.1%90%0.00 0.0%2%0.01 0.0%79.1%
C6 1.17 100%0.00 0.0%80%1.16 79.3%90%0.00 0.0%2%0.01 0.0%79.4%
C7 0.34 100%0.00 0.00 80%0.33 78.4%90%0.00 0.0%2%0.01 0.0%78.4%
C8 1.56 100%0.00 0.00 80%1.55 79.2%90%0.00 0.0%2%0.02 0.0%79.2%
C9 0.58 100%0.00 0.01 80%0.00 0.0%90%0.00 0.0%2%0.57 2.0%2.7%
Onsite Basins 9.84 71.9%
OS1 0.26 100%0.26 1.00 100%0.00 0.0%90%0.00 0.0%2%0.00 0.0%100.0%
OS2 0.92 100%0.01 0.01 100%0.00 0.0%90%0.00 0.0%2%0.92 2.0%2.6%
Basins Routed through Site 11.02 66.8%
OS3 38.11 100%0.00 0.00 100%0.00 0.0%90%0.00 0.0%2%38.11 2.0%2.0%
OS4 21.38 100%0.00 0.00 100%0.00 0.0%90%0.00 0.0%2%21.38 2.0%2.0%
Asphalt, Concrete
39817.00
Weighted
% Imp.
Basins Total Weighted %
Imp.Area (ac)Weighted %
Imp.
Recycled Asphalt Roofs
Weighted %
Imp.
COMPOSITE % IMPERVIOUS CALCULATIONS
% Imp. Area (ac)% Imp.Area (ac)Weighted % Imp.Basin ID Total Area (ac)% Imp.Area (ac)
Lawns
% Imp.
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 2 7/30/2025
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 2 of 2 7/30/2025
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:ARJ
Checked By:0
Date:7/28/25
C1 1.11 0.80 0.02 0.01 0.02 0.95 0.65 0.56 0.69 0.20 0.44 0.08 0.10 0.65 0.81
C2 0.89 0.80 0.00 0.00 0.00 0.95 0.66 0.70 0.88 0.20 0.23 0.05 0.07 0.75 0.94
C3 2.03 0.80 1.98 0.78 0.97 0.95 0.00 0.00 0.00 0.20 0.05 0.01 0.01 0.78 0.98
C4 1.08 0.80 1.07 0.79 0.99 0.95 0.00 0.00 0.00 0.20 0.01 0.00 0.00 0.79 0.99
C5 1.08 0.80 1.06 0.79 0.99 0.95 0.00 0.00 0.00 0.20 0.01 0.00 0.00 0.79 0.99
C6 1.17 0.80 1.16 0.79 0.99 0.95 0.00 0.00 0.00 0.20 0.01 0.00 0.00 0.80 0.99
C7 0.34 0.80 0.33 0.78 0.98 0.95 0.00 0.00 0.00 0.20 0.01 0.00 0.00 0.79 0.99
C8 1.56 0.80 1.55 0.79 0.99 0.95 0.00 0.00 0.00 0.20 0.02 0.00 0.00 0.79 0.99
C9 0.58 0.80 0.00 0.00 0.00 0.95 0.00 0.01 0.01 0.10 0.57 0.10 0.12 0.11 0.13
OS1 0.26 0.80 0.00 0.00 0.00 0.95 0.26 0.95 1.00 0.15 0.00 0.00 0.00 0.95 1.00
OS2 0.92 0.80 0.00 0.00 0.00 0.95 0.01 0.01 0.01 0.15 0.92 0.15 0.19 0.16 0.19
OS3 38.11 0.80 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.15 38.11 0.15 0.19 0.15 0.19
OS4 20.31 0.80 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.15 21.38 0.16 0.20 0.16 0.20
COMPOSITE RUNOFF COEFFICIENT CALCULATIONS
Basin ID Area (ac)2 - YEAR
C
100 -
YEAR C
39817.00
Runoff
Coefficient Area (ac)2 - YEAR C 100 - YEAR C Runoff Coefficient
Basins Total
Weighted 100
YEAR CRunoff Coefficient Area (ac)2 - YEAR C 100 -
YEAR C
Asphalt, Concrete, Roofs Lawns
Basins Total
Weighted 2 YEAR C
Recycled Asphalt
Total Area
(ac)
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 2 7/29/2025
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Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:
Checked By:0
Date:7/28/25
BASIN D.A.Hydrologic Impervious C2 C100 L S o t i - 2Year t i - 100 Year L t S t K VEL.t t COMP.t c-2 Year COMP.t c 100 - Year TOTAL Tc t c-2 Year t c-100 Year
ID (ac)Soils Group (%)(ft)(%)(min)(min)(ft)(%)(ft/s)(min)(min)(min)LENGTH (ft)Check (min)(min)
C1 1.11 C 2%0.65 0.81 10 2.0%9.7 6.2 10 1.0%20.0 2.0 0.1 9.8 6.3 20.0 10.1 10.0 6.0
C2 0.89 C 2%0.75 0.94 50 2.0%16.7 7.6 481 0.6%20.0 1.5 5.4 22.1 13.0 531.0 13.0 13.0 13.0
C3 2.03 C 2%0.78 0.98 50 2.0%15.2 5.7 568 0.5%20.0 1.4 6.7 21.9 12.4 617.8 13.4 13.0 12.0
C4 1.08 C 2%0.79 0.99 50 2.0%14.8 5.3 587 0.5%20.0 1.4 6.9 21.7 12.2 637.0 13.5 14.0 12.0
C5 1.08 C 2%0.79 0.99 50 2.0%14.8 5.2 612 0.5%20.0 1.4 7.2 22.0 12.4 662.0 13.7 14.0 12.0
C6 1.17 C 2%0.80 0.99 50 2.0%14.7 5.1 653 0.5%20.0 1.4 7.7 22.4 12.8 703.0 13.9 14.0 13.0
C7 0.34 C 2%0.79 0.99 30 1.5%12.8 4.7 206 0.5%20.0 1.5 2.4 15.1 7.1 236.0 11.3 11.0 7.0
C8 1.56 C 2%0.79 0.99 50 2.0%14.7 5.2 727 0.5%20.0 1.4 8.6 23.3 13.7 776.6 14.3 14.0 14.0
C9 0.58 C 2%0.11 0.13 20 20.0%14.1 13.8 520 0.4%20.0 1.3 6.9 21.0 20.6 540.0 13.0 13.0 13.0
OS1 0.26 C/B 2%0.95 1.00 17 1.0%5.3 3.5 376 0.5%15.0 1.1 5.9 11.2 9.4 393.0 12.2 11.0 9.0
OS2 0.92 C/B 2%0.16 0.19 100 1.0%80.7 77.4 421 1.0%15.0 1.5 4.7 85.4 82.1 520.8 12.9 13.0 13.0
OS3 38.11 C/B 2%0.15 0.19 100 1.0%81.2 78.0 1100 0.6%5.0 0.4 47.3 128.5 125.3 1200.0 16.7 17.0 17.0
OS4 21.38 C/B 2%0.16 0.20 100 1.0%80.5 77.2 1935 0.3%16.0 0.8 40.3 120.8 117.5 2035.0 21.3 21.0 21.0
Notes:
Velocity V = K*St^0.5
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN
39817.00
FINAL
Time of Concentration -Check
ARJ
(Tc)DATA
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 7/29/2025
Project Name:Front Range RV Boat and Storage
Subdivision:RV, Boat & Storage Project No.:
Location:Fort Collins Calculated By:ARJ
Design Storm:Checked By:0
Date:
TRAVEL TIME
STREET
De
s
i
g
n
P
o
i
n
t
Ba
s
i
n
I
D
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e
a
(
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.
tc
(
m
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)
-
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0
0
Y
e
a
r
C*
A
(
a
c
)
I
(
i
n
/
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)
Q
(
c
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tc
(
m
i
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C*
A
(
a
c
)
I
(
i
n
/
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r
)
Q
(
c
f
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)
Qst
r
e
e
t
(
c
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)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Qpi
p
e
(
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A
(
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o
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e
(
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)
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(
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)
Ve
l
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y
(
f
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s
)
tt
(
m
i
n
)
REMARKS
sheet drains over riprap on the site and then into the RG
1 C1 1.11 0.65 10.0 0.72 2.21 1.6
OS1 0.26 0.95 11.0 0.25 2.13 0.5
OS2 0.92 0.16 13.0 0.14 1.98 0.3
drains into swale
2 C2 0.89 0.75 13.0 0.67 1.98 1.3 13.0 1.06 1.98 2.1
3 C3 2.03 0.78 13.0 1.59 1.98 3.1 drains into RG
4 C4 1.08 0.79 14.0 0.86 1.92 1.7 drains into RG
5 C5 1.08 0.79 14.0 0.85 1.92 1.6 drains into RG
6 C6 1.17 0.80 14.0 0.93 1.92 1.8 drains into RG
7 C7 0.34 0.79 11.0 0.26 2.13 0.6 drains into RG
8 C8 1.56 0.79 14.0 1.24 1.92 2.4 drains into RG into pond
Basins C2, C3, C4, C5,C6, C7, C8, C9 AND Basins OS1 and OS2
9 C9 0.58 0.11 13.0 0.06 1.98 0.1 14.0 6.85 1.92 13.2 Goes into overflow channel
o3 OS3 38.11 0.15 17.0 5.72 1.75 10.0
o4 OS4 21.38 0.16 21.0 3.38 1.56 5.3
Total flow out of the site - From the PEC Joint Outfall Report
10 Refer to PEC SWMM model for the joint outfall outflow
Notes:
Street and Pipe C*A values are determined by Q/i using the catchment's intensity value.
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 7/29/2025
Project Name:Front Range RV Boat and Storage
Subdivision:RV, Boat & Storage Project No.:
Location:Fort Collins Calculated By:ARJ
Design Storm:Checked By:0
Date:
TRAVEL TIME
STREET
De
s
i
g
n
P
o
i
n
t
Ba
s
i
n
I
D
Ar
e
a
(
a
c
)
Ru
n
o
f
f
C
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e
f
f
.
tc
(
m
i
n
)
-
1
0
0
Y
e
a
r
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
tc
(
m
i
n
)
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
Qst
r
e
e
t
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Qpi
p
e
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Pi
p
e
S
i
z
e
(
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n
c
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e
s
)
Le
n
g
t
h
(
f
t
)
Ve
l
o
c
i
t
y
(
f
p
s
)
tt
(
m
i
n
)
REMARKS
sheet drains over riprap on the site and then into the RG
1 C1 1.11 0.81 6.0 0.90 9.31 8.4
OS1 0.26 1.00 9.0 0.26 8.03 2.1
OS2 0.92 0.19 13.0 0.18 6.92 1.2
drains into swale
2 C2 0.89 0.94 13.0 0.84 6.92 5.8 13.0 1.28 6.92 8.9
3 C3 2.03 0.98 12.0 1.99 7.16 14.2 drains into RG
4 C4 1.08 0.99 12.0 1.07 7.16 7.7 drains into RG
5 C5 1.08 0.99 12.0 1.07 7.16 7.7 drains into RG
6 C6 1.17 0.99 13.0 1.16 6.92 8.0 drains into RG
7 C7 0.34 0.99 7.0 0.33 8.80 2.9 drains into RG
8 C8 1.56 0.99 14.0 1.55 6.71 10.4 drains into RG into pond
Basins C2, C3, C4, C5,C6, C7, C8, C9 AND Basins OS1 and OS2
9 C9 0.58 0.13 13.0 0.08 6.92 0.6 14.0 8.53 6.71 57.2 Goes into overflow channel
o3 OS3 38.11 0.19 17.0 7.15 6.10 43.6
o4 OS4 21.38 0.20 21.0 4.22 5.46 23.0
Total flow out of the site - From the PEC Joint Outfall Report
10 350.0
Notes:
Street and Pipe C*A values are determined by Q/i using the catchment's intensity value.
STORM DRAINAGE SYSTEM DESIGN
STANDARD FORM SF-3
(RATIONAL METHOD PROCEDURE)
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF
7/28/25
STREET
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 7/29/2025
Front Range Storage
Preliminary Drainage Report
20
APPENDIX C – HYDRAULIC CALCULATIONS
Project:
ID:
Soil Type:
Design Information:
Design Discharge Q =230 cfs
Circular Culvert:
Barrel Diameter in Inches D =36 inches
Inlet Edge Type (Choose from pull-down list)Grooved Edge Projecting
OR:
Box Culvert:OR
Barrel Height (Rise) in Feet H (Rise) =ft
Barrel Width (Span) in Feet W (Span) =ft
Inlet Edge Type (Choose from pull-down list)
Number of Barrels # Barrels =4
Inlet Elevation 4981.76 Elev IN =4982.4 ft
Outlet Elevation OR Slope 0.0050 Elev OUT =4981.76 ft
Culvert Length L =128.7 ft
Manning's Roughness n =0.013
b =0
Exit Loss Coefficient kx =1
Tailwater Surface Elevation Yt, Elevation =4982.96 ft
Max Allowable Channel Velocity V =7 ft/s
Calculated Results:1
Culvert Cross Sectional Area Available A =7.07 ft2
n =3.00 ft
Culvert Critical Depth Yc =2.46 ft
Froude Number Fr =-Pressure flow!
Entrance Loss Coefficient ke =0.20
Friction Loss Coefficient kf =0.93
Sum of All Loss Coefficients ks =2.13 ft
Headwater:
Inlet Control Headwater HWI =4.15 ft
Outlet Control Headwater HWO =4.27 ft
Design Headwater Elevation HW =4986.67 ft
Headwater/Diameter OR Headwater/Rise Ratio HW/D =1.42
Outlet Protection:
Flow/(Diameter^2.5)Q/D^2.5 =3.69 ft0.5/s
t =1.20 ft
Tailwater/Diameter Yt/D =0.40
Expansion Factor 1/(2*tan(Θ)) =3.78
t =32.86 ft
Width of Equivalent Conduit for Multiple Barrels Weq =12.00 ft
Length of Riprap Protection Lp =30 ft
Width of Riprap Protection at Downstream End T =20 ft
Adjusted Diameter for Supercritical Flow Da =-ft
50 min=9 in
Nominal Riprap Size d50 nominal=12 in
MHFD Riprap Type Type =M
DETERMINATION OF CULVERT HEADWATER AND OUTLET PROTECTION
Front Range Self Storage -> 4 - 36" CULVERTS
MHFD-Culvert, Version 4.01 (April 2025)
Choose One:
Sandy
Non-Sandy
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:ARJ
Checked By:0
Date:7/28/25
Units
C 3.0
L 48.98 ft
H 0.53 ft
Q 57.24 cfs
39817.00
OVERFLOW WEIR
Q = Discharge over the weir (cfs)
C = Discharge coefficient (dimensionless; varies by weir type,
usually 2.6–3.0 for broad-crested weirs in Imperial Customary
units)
L = Length of the weir crest (ft )
H = Head (depth of water above the crest ft )
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 7/30/2025
Front Range Storage
Preliminary Drainage Report
21
APPENDIX D – WATER QUALITY CALCULATIONS
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:39817.00
Calculated By:ARJ
Checked By:0
Date:7/28/25
Basin (ac)% Imp.
C1 1.11 60.7%
WQCV Drain Time (hr):12
Coefficient, a (Figure 3.2):0.8
WQCV (in):0.19
WQ Tributary Areas
WQCV - RAIN GARDEN # 1
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 3 7/30/2025
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:39817.00
Calculated By:ARJ
Checked By:0
Date:7/28/25
Basin (ac)% Imp.
OS1 0.26 100.0%
OS2 0.92 2.6%
C2 0.89 74.0%
C3 2.03 78.0%
C4 1.08 79.0%
C5 1.08 79.1%
C6 1.17 79.4%
C7 0.34 78.4%
C8 1.56 79.2%
C9 0.58 2.7%
WQCV Drain Time (hr):12
Coefficient, a (Figure 3.2):0.8
WQCV (in):0.21
WQ Tributary Areas
WQCV - RAIN GARDEN # 2
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 2 of 3 7/30/2025
Note: 1.2 was not applied this is only used for WQ in a detention Pond and not the WQ for RG(s)
This is based on guidance City of Fort Collins Staff has given JR Engineering
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 3 of 3 7/30/2025
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =60.8 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.608
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.19 watershed inches
3 2
D) Contributing Watershed Area (including rain garden area)Area =48,352 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =770 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =6 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical)Z =4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =588 sq ft
D) Actual Flat Surface Area AActual =1649 sq ft
E) Area at Design Depth (Top Surface Area)Top =1967 sq ft
F) Rain Garden Total Volume VT=904 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
See city of Fort Collins Detail
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =2.3 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =770 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =5/8 in
Design Procedure Form: Rain Garden (RG)
ARJ
JR ENGINEERING
July 29, 2025
FRONT RANGE RV BOAT & STORAGE
Basin C1
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
No. 1 RAIN GARDEN UD-BMP_v3.07.xlsm, RG 7/29/2025, 4:16 PM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
ARJ
JR ENGINEERING
July 29, 2025
FRONT RANGE RV BOAT & STORAGE
Basin C1
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
No. 1 RAIN GARDEN UD-BMP_v3.07.xlsm, RG 7/29/2025, 4:16 PM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =67.4 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.674
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.21 watershed inches
3 2
D) Contributing Watershed Area (including rain garden area)Area = 431,680 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =7,591 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =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 vertical walls)
C) Mimimum Flat Surface Area AMin =5819 sq ft
D) Actual Flat Surface Area AActual =8720 sq ft
E) Area at Design Depth (Top Surface Area)Top =13202 sq ft
F) Rain Garden Total Volume VT=8,586 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
See City of Fort Collins Detail
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =2.3 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =7,591 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =1 15/16 in
Design Procedure Form: Rain Garden (RG)
ARJ
JR ENGINEERING
July 29, 2025
FRONT RANGE RV BOAT & STORAGE
Basins OS1-OS2 and Basins C2-C9
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
No. 2 RAIN GARDEN UD-BMP_v3.07.xlsm, RG 7/29/2025, 4:17 PM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
ARJ
JR ENGINEERING
July 29, 2025
FRONT RANGE RV BOAT & STORAGE
Basins OS1-OS2 and Basins C2-C9
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
No. 2 RAIN GARDEN UD-BMP_v3.07.xlsm, RG 7/29/2025, 4:17 PM
Front Range Storage
Preliminary Drainage Report
22
APPENDIX E – REFERENCES
Model Scenario:
Duplicate Effective = ICON conversion of
Effective MODSWMM model to EPA SWMM +
Recent Development Updates
Existing = DE + Recent
Hydrology LOMRs
SWMM Element
ICON 2014 Model - Duplicate Effective SWMM
(v 5.0.022 - from Report)
Existing Conditions SWMM
v5.1.012 As-Built v5.1.006
As-Built v5.1.011
(w/ pond problem)
As-Built v5.1.012
(w/ pond problem)
As-Built v5.1.012
(Raised Ponds)
As-Built v5.1.012
(Final)
Difference:
Exist. Cond. (v5.1.012) -
Dup. Eff. Model (ICON)
Difference:
v.011 - v.006
Difference:
v.012 - v.011
Difference:
v.012 Raised Ponds -
v.006
Difference:
v.012 Final - v.006
Model Notes:Eff. Model Conversion/ Update Corrected 'Warning 10' problem by
rasing invert elevation of 16 ponds.
Updated with corrected ponds
(raised inverts) and updated
Larimer-Weld Canal model run
Should be very close to
v5.1.006
HECRAS) caused flow changes. Report
Table 5.7 shows these flow are now close
again to the CLOMR flows.
913 539.5 540.4 47.97 48.0 48.0 48.0 48.0 0.8 0.00 0.00 0.00 0.00
914 3079.6 3090.4 274.21 274.2 274.2 274.2 274.2 10.8 0.00 0.00 0.00 0.00
Node Discharge - 100yr (cfs)Comparison
As-Built
These are the same model input file, run in 3 SWMM versions These are the same model input file, run
in 3 SWMM versions - note differences
beteween v..006 and v.011
TI
M
B
E
R
L
I
N
E
R
O
A
D
COUNTY RD 52
MULBERRY ST
MOUNTAIN VISTA DR
IN
T
E
R
S
T
A
T
E
2
5
CO
U
N
T
Y
R
D
5
CO
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D
1
3
E. VINE DR
BO
X
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L
D
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BO
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L
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CR
E
E
K
LAK
E
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NO
R
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A
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A
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GR
A
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S
E
R
V
O
I
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#
3
COUNTY RD 50
0
32
83
134
195
2800
3230
3699
4950
6075
6152
6194
6215
6275
8210
9025
9713
10230
10600
11615
11635
11663
11672
11681
11723
11756
11945
11897
11892
11875
11832
11790
13050
13415
13643
14297
14550
15360
15974
16550
17225
17318
17341
17425
17985
19405
20080
20330
20670
20705
20801
20950
21990
23680
25281
*
*
*LOCATION OF CONSTRUCTED SIDE SPILL WEIR
0 2000'4000'
SCALE: 1" = 2000'
1000'
FIGURE 5.1
LARIMER & WELD
CANAL
100-YR SPILLS
LEGEND:
CROSS SECTION
LOCATION SECTION ID
(STATION)
APPROXIMATE SPILL LIMITS
Dr
a
w
i
n
g
N
a
m
e
:
F:
\
3
2
-
1
6
6
4
.
3
1
B
O
X
E
L
D
E
R
L
O
M
R
\
R
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P
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5
.
1
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D
W
G
Th
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,
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1
5
,
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1
8
11
:
2
3
A
M
B
y
:
RI
C
K
S
,
R
O
N
A
L
D
SPILL LIMITS ID
25281
Spill
Location
Existing
Condition
Flows
(Pre-Project)
As-built Flows
(Post-Project)Difference
cfs cfs cfs
A 509 166 -344
B 452 105 -347
C 2555 2513 -42
D 2147 2 -2145
E 34 0 -34
F 1731 740 -991
G 65 37 -28
H 108 108 0
TH-12
TH-2
TH-1
TH-4
TH-13
TH-5
TH-3
TH-14
TH-6
TH-15
TH-7
I-
2
5
E Vine DR.
I-
2
5
Canal
N
C
R
5
E CR 50
Site
NE FRONTAGE RDLEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORINGS PERFORMED FOR NEWT
3 PIPELINE PROJECT (FC10581)
TH-1
TH-12
ERIC KELLEY C/O JR ENGINEERING LLC
MOUNTAIN VISTA PROPERTY
CTL I T PROJECT NO. FC10813-115
FIGURE 1
Locations of
Exploratory Borings
VICINITY MAP
(FORT COLLINS, COLORADO)
NOT TO SCALE
550'275'
APPROXIMATE
SCALE: 1" = 550'
0'
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
6/12
14/12
9/12
11/12
50/10
WC=11.2
DD=109
SW=0.0
SS=0.370
WC=4.7
DD=116
-200=23
WC=8.7
DD=114
SW=-0.1
TH-1
10/12
15/12
WC=19.9
DD=104
SW=0.9
SS=1.300
TH-2
7/12
9/12
9/12
17/12
37/12
WC=10.1
DD=114
-200=45
WC=10.8
DD=116
SW=0.0
TH-3
9/12
26/12
WC=23.2
DD=106
SW=0.4
TH-4
21/12
10/12
29/12
8/12
WC=5.6
DD=114
SW=0.0
SS=0.800
TH-5
7/12
4/12
50/5
WC=25.6
DD=96
-200=83
WC=17.2
DD=111
SW=-0.1
TH-6
7/12
2/12
4/12
WC=17.6
DD=107
SW=0.3
SS=0.040
TH-7
DE
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DE
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Summary Logs of
Exploratory Borings
FIGURE 2
ERIC KELLEY C/O JR ENGINEERING LLC
MOUNTAIN VISTA PROPERTY
CTL | T PROJECT NO. FC10813-115
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
8/12
42/12
40/12
26/12
WC=0.0DD=102SW=1.3SS=1.600
WC=5.1-200=7
WC=0.0DD=102SW=1.3SS=1.600
WC=5.1-200=7
TH-12
11/12
14/12
12/12
9/12
WC=10.3-200=16WC=10.3-200=16
TH-13
14/12
6/12
15/12
31/12
WC=0.0DD=113SW=0.0SS=0.490
WC=0.0DD=113SW=0.0SS=0.490
TH-14
11/12
5/12
7/12
7/12
WC=30.8DD=91WC=30.8DD=91
TH-15
DRIVE SAMPLE. THE SYMBOL 8/12 INDICATES 8 BLOWS OF A 140-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES.
SAND, CLAYEY, SILTY, SLIGHTLY MOIST TO MOIST, LOOSE TO MEDIUM DENSE, BROWN,
TAN, RUST (SC)
1.
4.
LEGEND:
CLAY, SANDY, MOIST, STIFF, BROWN (CL)
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THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN
THIS REPORT.
NOTES:
WATER LEVEL MEASURED MAY 1, 2023
GRAVEL, SANDY, SLIGHTLY MOIST TO WET,MEDIUM DENSE TO VERY DENSE, REDDISH
BROWN (GP)
INDICATES DEPTH WHERE HOLE CAVED PRIOR TO SECONDARY
GROUNDWATER MEASUREMENTS.
INDICATES MOISTURE CONTENT (%).
INDICATES DRY DENSITY (PCF).
INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%).
INDICATES PASSING NO. 200 SIEVE (%).
INDICATES LIQUID LIMIT.
INDICATES PLASTICITY INDEX.
INDICATES UNCONFINED COMPRESSIVE STRENGTH (PSF).
INDICATES SOLUBLE SULFATE CONTENT (%).
3.
DE
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WATER LEVEL MEASURED AT TIME OF DRILLING.
Summary Logs of
Exploratory Borings
BORINGS 1-7 WERE DRILLED ON APRIL 21ST, 2023 USING 4-INCH DIAMETER
CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG.
FIGURE 3
WC
DD
SW
-200
LL
PI
UC
SS
-
-
-
-
-
-
-
-
ERIC KELLEY C/O JR ENGINEERING LLC
MOUNTAIN VISTA PROPERTY
CTL | T PROJECT NO. FC10813-115
BORINGS 12-15 WERE PERFORMED ON NOVEMBER 8TH, 2022 AS A PART OF THE NEWT 3
PIPELINE PROJECT (FC10581)
2.
HYDROLOGY AND HYDRAULICS REPORT
Joint Outfall Channel Design
COLORADO PARKS AND WILDLIFE
FORT COLLINS OFFICE RELOCATION
LARIMER COUNTY, COLORADO
AND
FRONT RANGE STORAGE
CITY OF FORT COLLINS, COLORADO
PEC PROJECT NO. 210628-000
JUNE 2025
PREPARED BY
PROFESSIONAL ENGINEERING CONSULTANTS PA
351 Linden Street Fort Collins, CO 80524 316-262-2691 www.pec1.com
Joint Outfall Channel Hydraulics Report
i
Table of Contents
1.0 Introduction .......................................................................................................................................................... 1
2.0 Proposed Improvements .................................................................................................................................. 2
3.0 Floodplain Impact Analysis ............................................................................................................................. 3
3.1 Basin Description and Analysis ..................................................................................................................... 3
3.2 Analysis Methods ................................................................................................................................................... 5
3.3 Scenario 1: Site Detention for Historic Release ........................................................................................ 7
3.4 Scenario 2: Site Detention for Water Quality ........................................................................................... 10
4.0 Joint Outfall Channel Design ......................................................................................................................... 13
4.1 Channel Inlet Design .......................................................................................................................................... 15
4.2 Channel Design ..................................................................................................................................................... 16
4.3 Channel Outlet Design ....................................................................................................................................... 17
5.0 Permitting ........................................................................................................................................................... 18
6.0 Variances ............................................................................................................................................................. 18
7.0 Conclusions ......................................................................................................................................................... 18
8.0 References........................................................................................................................................................... 18
List of Tables
Table 1: SWMM-Predicted 100-year Discharge in Boxelder Creek for Scenario 1 ......................................... 10
Table 2:SWMM-Predicted 100-year Discharge in Boxelder Creek for Scnario 2 ............................................ 12
Table 3: Manning’s n Values for Joint Outfall Channel Design ....................................................................... 14
Table 4: Joint Outfall Channel Geometry ........................................................................................................ 17
List of Figures
Figure 1: Project Vicinity Map
Figure 2: Site Plan, CPW Site
Figure 3: Site Plan, Front Range Storage Development
Figure 4: Regional Context Map, exhibit with title block
Figure 5: Offsite Flow Paths and Depths
Figure 6: Existing SWMM Model Basins in Projects Vicinity
Figure 7: SWMM Model Hydrograph, Scenario 2
Figure 8: HEC-RAS Results Summary, Scenario 2
Figure 9: SWMM Model Hydrograph, Scenario 2
Figure 10: HEC-RAS Results Summary, Scenario 2
Joint Outfall Channel Hydraulics Report
ii
Figure 11: Outfall Channel Overview
Figure 12: Inlet Configuration for the Outfall Channel
Figure 13: Joint Outfall Channel HEC-RAS 2D Results Map
List of Appendices
Appendix A: Correspondence with Larimer and Weld Irrigation Company
Appendix B: Pertinent Sections; 2019 LOMR and 2014 Box Elder Creek Basin Flood Study
Appendix C: SWMM Model Results
Appendix D: Boxelder Creek HEC-RAS Results
Appendix E: Culvert Design
Appendix F: Riprap Design
I hereby certify that this report (plan) for the drainage analysis and design of the joint outfall channel
for the Colorado Parks and Wildlife Office Relocation and the Front Range Storage Projects was
prepared by me (or under my direct supervision) for the owners thereof and meets the criteria in the
Larimer County Stormwater Design Standards and City of Fort Collins Stormwater Criteria Manual.
______________________________________
Registered Professional Engineer
State of Colorado No. _______
Joint Outfall Channel Hydraulics Report
1
1.0 Introduction
This report presents the hydrologic analysis and hydraulic design of a proposed joint outfall
channel which will convey onsite and offsite stormwater runoff from two future land development
projects. The future land development projects consist of the Colorado Parks and Wildlife (CPW)
Fort Collins office relocation and the Front Range Storage development. This report is
supplementary to the drainage reports prepared for each of the projects, presenting the results of
the joint outfall channel design.
Both project sites are located in the vicinity of I-25 and Mountain Vista Drive and drain to Boxelder
Creek. The proposed joint outfall channel will convey stormwater discharged from both projects
and represents a solution to stormwater management that will benefit both projects. The
proposed channel will discharge into the Boxelder Creek FEMA-designated Zone AE floodplain and
floodway. As a result, a floodplain impacts analysis was performed as part of this study, ultimately
showing a “No-Rise” condition.
Both project sites are located in the NW Quarter of Section 03, Township 07N, Range 68 W of the
6th Principal Meridian and can be accessed from the I-25 frontage road adjacent to northbound I-
25, south of Mountain Vista Drive. A project vicinity map is provided as Figure 1.
Figure 1 – Project Vicinity Map
The CPW project site is located at the southeast corner of the I-25 and Mountain Vista Drive
interchange at 1435 NE Frontage Road in Larimer County, Colorado northeast of the City of Fort
Collins. The project site is approximately 27-acre property. Figure 2 is a site plan for the CPW
project.
EXHIBIT A
Joint Outfall Channel Hydraulics Report
2
The Front Range Storage development is located immediately south of the CPW property at 1312
NE Frontage Road and is located with the City of Fort Collins. The proposed storage development
will be approximately 17 acres of the property’s total of approximately 104 acres. Figure 3 is a site
plan for the Front Range Storage Development.
2.0 Proposed Improvements
The proposed CPW project includes an approximate 30,000 square-foot 2-story administration
office building, seven roughly 5,800 square-foot storage buildings, approximate 4,000 square-feet
of existing structures to remain, 0.42 acres of gravel pavement not accessible by the public for
vehicle traffic and storage, and 8.38 acres of pavement for public parking, CPW staff parking areas,
and associated driveways. The remaining 16.67 acres will be grass or other landscaping.
A new local industrial road will also be constructed immediately south of the CPW site as part of
improvements for the proposed Front Range Storage development. This new road will allow access
to the northern portion of the Front Range Storage development. Access to the CPW site is
proposed to occur directly off this new northern Front Range Storage development access road. A
second access to the Front Range Storage development is proposed to occur at an existing
driveway to the south. Figure 4 depicts the locations of the two project sites, the adjacent roadway
infrastructure, and proposed driveway access to the CPW site.
The CPW project and the Front Range Storage project are located on properties that have
historically drained southward into the Larimer and Weld Canal (LWC). The Larimer and Weld
Irrigation Company (LWIC) will not accept developed site runoff from either of the two projects, as
indicated in the correspondence provided in Appendix A. Consequently, a joint outfall channel is
proposed to collect stormwater from both developed sites and convey it southeastward directly to
Boxelder Creek, as depicted in Figure 4. The joint outfall channel’s design is being submitted for
approval by Larimer County and the City of Fort Collins.
Additionally, a drainage basin to the north of Mountain Vista Drive conveys stormwater to the
south, through culverts at the interchange of I-25 and Mountain Vista, and generally south along
the frontage road right-of-way. This offsite flow crosses the frontage road and will be collected via
grading improvements proposed for the two projects and will be conveyed in the joint outfall
channel with project runoff. Details on offsite flow location and peak discharge are provided in
later sections.
A Westrian Company
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Figure 4 – Regional Context Map
3.0 Floodplain Impact Analysis
3.1 Basin Description and Analysis
The project sites are located within the Boxelder Creek watershed, a subbasin of the Cache la
Poudre River and ultimately the South Platte River. The basin that comprises the offsite runoff as
well as runoff from the two project sites is approximately 419 acres in area. The Web Soil Survey
from NRCS identifies the basin as having primarily type C soils with moderate to high runoff
potential.
Both project sites have benefited from Boxelder Basin improvements implemented by the
Boxelder Basin Regional Stormwater Authority. A Master Plan for improvements was prepared by
ICON Engineering in 2014, and CLOMR and LOMR reports were prepared by Ayres Associates in
2015 and 2018, respectively. With the completion of the basin improvements as documented in
the Ayres reports, the subject properties and a segment of the I-25 frontage road were removed
from the floodplain. However, a flow path from the offsite basin north of Mountain Vista, and
including the two properties proposed for development, has remained.
Joint Outfall Channel Hydraulics Report
4
Modeling by ICON and Ayres has evaluated flow from this sub-basin under existing conditions and
predicted that during the 100-year event approximately 274 cubic feet per second (cfs) currently
flows as sheet flow into the Larimer and Weld Canal. Additional details regarding upstream
diversions and overflow pathways are provided in Appendix B.
PEC used HEC-RAS 2D modeling to evaluate the stormwater runoff flowing south from solely the
basin north of Mountain Vista Drive and independent of the two project sub-basins. Results
indicate that approximately 180 cfs from the 100-year storm flows south along the I-25 frontage
road and overtops it at two locations near the existing CPW access at depths reaching
approximately 0.5 feet (see Figure 5).
Figure 5 – Offsite Flow Paths and Depths
The CPW and Front Range Storage sites lie within the same sub-basin: south of Mountain Vista
Drive, east of the I-25 frontage road, and north of the Larimer and Weld Canal. The two sites are
separated into two basins for site development reasons. Historically the CPW site flowed
southward primarily as sheet flow, discharging to the property owned by Freedom Storage LLC.
The developed CPW site basin will drain toward its southwest corner.
The Freedom Storage LLC property, which historically has been farmland, historically drained
almost directly south, with runoff collecting in a pair of wide shallow folds before emptying into
Joint Outfall Channel Hydraulics Report
5
the canal. The property to be developed as Front Range Storage will be graded to drain toward its
southeast corner.
Modeling of runoff from the 2 project sites is discussed in Sections 3.3 and 3.4.
The joint outfall channel will be constructed and maintained to avoid discharge to the LWC and
instead will flow south and east before discharging into Boxelder Creek as depicted in Figure 4.
Two-dimensional HEC-RAS modeling was used to model runoff from the offsite basin and from the
two proposed projects as conveyed through the joint outfall channel. Channel modeling is
discussed in Section 4.
3.2 Analysis Methods
The hydrologic and hydraulic evaluation for the joint outfall channel involves five separate models
that work in conjunction with each other. Four of the models are part of the effective FEMA study
for the Boxelder Creek watershed. The fifth was created to analyze the performance of the
proposed joint outfall channel. The models are listed below:
1. {FEMA Hydrology} – A SWMM model studying the hydrology of the Boxelder Creek watershed.
The flow rates from this model are used as the hydrologic input for the remaining four models.
2. {Boxelder Creek Upper} – A HEC-RAS 1D steady-state model of the Boxelder Creek from its
headwaters to its confluence with the Larimer and Weld Canal.
3. {Boxelder Creek Lower} – A HEC-RAS 1D steady-state model of the Boxelder Creek from
immediately downstream of the LWC to its confluence with the Poudre River.
4. {Larimer and Weld Canal} – A HEC-RAS 1D unsteady-state model of the LWC.
5. {Joint Channel Outfall} – A HEC-RAS 2D model of the proposed project sites, joint outfall
channel, and LWC.
The floodplain impact study procedure is outlined below. Note that the only potential change to
the floodplain itself comes from the change in flow rates resulting from the proposed projects. The
joint outfall channel will converge with the floodplain but will only act as an ineffective flow area
for additional floodplain storage.
1. {Duplicate Effective} – The four FEMA models were re-run and compared to the effective
FEMA study to check for matching results.
2. {Proposed Hydrology} – The increase in impervious area from the proposed site developments
and changing flow patterns from the joint outfall channel were incorporated into the FEMA
hydrology model.
3. {Proposed Hydraulics – Steady State} – The new peak flow rates were incorporated into the
steady flow data of the Boxelder Creek Upper model.
Joint Outfall Channel Hydraulics Report
6
4. {Proposed Hydraulics – Unsteady State} – The new hydrographs along the Larimer and Weld
Canal were incorporated into the Larimer and Weld Canal model.
5. {Proposed Hydrology} – The new hydrographs exiting the LWC and entering back into the
Boxelder Creek watershed were incorporated into the FEMA hydrologic model.
6. {Proposed Hydraulics – Steady State} – The new peak flow rates were incorporated into the
steady flow data of the Boxelder Creek Lower model.
7. {Impacts Analysis} – Comparisons between the duplicate effective and proposed conditions
water surface elevations were made to quantify the impacts of the changing flow rates within
the Boxelder Creek.
The FEMA-effective hydrologic model is an EPA-SWMM version 5.1.012 model. This study utilized
PCSWMM version 7.7.3910, a proprietary software developed by Computational Hydraulics
International (CHI) that incorporates a graphical user interface and additional tool-spaces with the
EPA-SWMM calculation engine. The engine for EPA-SWMM version 5.1.012 was utilized in this
study to maintain consistency across the hydrologic modeling.
As stated in Section 2.0, the proposed site developments are not allowed to continue to drain into
the Larimer and Weld Canal as they do in existing conditions. Thus, flow originating upstream of
the project sites and direct runoff from the project sites need to be intercepted by the joint outfall
channel and re-routed to Boxelder Creek. This was accomplished in the SWMM model by creating
a new conduit representative of the joint outfall channel and discharging it into Boxelder Creek
immediately upstream of its confluence with the Larimer and Weld Canal.
Two design scenarios were completed and will be discussed in further detail below: Scenario 1
pertains to satisfying traditional detention with design/construction for historical release, and
Scenario 2 pertains to a “beat-the-peak” solution with decreased storage sufficient for water
quality management. In either case, the intent is to perform project design in such a manner that
project stormwater discharge results in meeting a no-rise criterion for water surface elevations in
Boxelder Creek.
In both scenarios, the flow rates presented by the SWMM model were incorporated into the FEMA
hydraulic models to analyze impacts to the Base Flood Elevations (BFEs) in Boxelder Creek. The
first hydraulic model changed in this process is the Boxelder Creek Upper 1D steady-state model.
The steady flow data was updated at Cross Section 31117 (Lettered AZ) where the proposed joint
outfall channel intersects Boxelder Creek.
The second hydraulic model in this process is the Larimer and Weld Canal 1D unsteady-state
model. This model represents the Larimer and Weld Canal with cross sections representing its
channel and lateral structures representing overflow points, both where water is overflowing into
the canal and where water is overflowing out of the canal. Between the proposed project sites and
the canal’s confluence with Boxelder Creek, there are four such points where water is overflowing
into the canal:
Joint Outfall Channel Hydraulics Report
7
• SWMM Node 913 represents flow within the median of I-25, and its hydrograph
represents inflow into the canal at HEC-RAS Cross Section 11756.
• SWMM Node 914 represents natural flow from the project sites and upstream areas into
the canal at the HEC-RAS lateral structure between Cross Sections 11615 and 10600.
• SWMM Node 917 represents an approximately 26-acre undeveloped basin (sub-basin 98)
that overflows into the canal at the HEC-RAS lateral structure between Cross Sections
10230 and 9025.
• SWMM Node 916 represents the Boxelder Creek overflow into the canal at HEC-RAS Cross-
Section 8210. This point is the downstream extent of the Upper Boxelder Creek FEMA
model and represents Cross Section 31117 in the Boxelder Creek model.
There are two locations along this same stretch of the Larimer and Weld Canal where overflow
from the canal enters back into the Boxelder Creek watershed:
• SWMM Node 915 represents the overflow from the canal at lateral structure 11633 back
into the Boxelder watershed.
• SWMM Node 918 represents the overflow from the canal at lateral structure 9713 back
into the main reach of the Boxelder Creek. This point is the upstream extent of the Lower
Boxelder Creek FEMA model.
The proposed conditions scenarios modified all four inflow hydrographs into the Larimer and
Weld Canal. Due to the joint outfall channel intercepting all flow between the project sites and
Boxelder Creek, SWMM Nodes 914 and 917 produce “empty” hydrographs, and the flow into the
canal at those locations is 0 cfs for the duration of the study. SWMM Node 913 is unaffected by
proposed project conditions.
The hydrograph at SWMM Node 916, representative of Boxelder Creek, is changed by the
proposed conditions and the new hydrograph was input into the canal HEC-RAS model to produce
the subsequent outflow hydrographs from the canal at SWMM Nodes 915 and 918. The new
outflow hydrographs were applied to SWMM Nodes 915 and 918 and the model was re-run to
produce the flow rates for the Lower Boxelder Creek model.
The third hydraulic model is the Boxelder Creek Lower 1D steady-state model. The proposed
conditions flow rates were incorporated into the model beginning at Cross Section 31043 (AY)
and carried down through Lower Boxelder Creek at cross-section 7663 (S). Downstream of this
Cross Section, the flow rates naturally remain at the existing conditions levels outside of the
influence of the proposed projects.
3.3 Scenario 1: Site Detention for Historic Release
The proposed conditions for Scenario 1 included site detention designs to regulate proposed
outflow from both the CPW and Front Range Storage developments to historic release rates. The
goal of these stormwater detention ponds would be to satisfy water quality and quantity
requirements as set forth by Larimer County and the City of Fort Collins. The SWMM hydrology
Joint Outfall Channel Hydraulics Report
8
model was modified for this scenario by creating storage nodes upstream of the joint outfall
channel based on the site design stage-area tables for the ponds. The proposed impervious areas
were modeled to runoff into the storage nodes with outlet rating curves representative of the site
design before being conveyed by the outfall channel.
The proposed project sites are located within sub-basin 99 of the SWMM model, which is depicted
in Figure 6.
Figure 6 – Existing SWMM Model Basins in Projects Vicinity
In existing conditions, sub-basin 99 was modeled for the Boxelder Basin Improvements Project as a
108-acre basin with impervious areas totaling 5% of the overall area. The basin was modified for
the proposed projects Scenario 1 by splitting it into three basins representative of anticipated
project conditions:
• Sub-basin 99.1 represents approximately 4.5 acres of the CPW site with an impervious
area covering 41% of the sub-basin.
• Sub-basin 99.2 represents the Front Range Storage development and eastern property on
the parcel owned by Freedom Storage, Inc. with approximately 57 acres and 17%
impervious cover.
• Sub-basin 99.3 represents approximately 42.5 acres of the CPW site and property to the
east of the CPW site with a combined impervious area covering 24% of the sub-basin.
The portion of sub-basin 99 that includes the I-25 travel lanes and median, conveying runoff south
Joint Outfall Channel Hydraulics Report
9
to the LWC in the median at Node 913 was excluded from the analysis because this flow path is
unaffected by development within the sub-basin. This runoff scenario achieved its site goal of
limiting proposed outflows to historic release rates, but it elongated the hydrograph leaving the
project sites and entering into Boxelder Creek. This attenuation of flow forced the peak outflow
rates from the sites to coincide with the peak of the hydrograph for Boxelder Creek, which
increased the peak FEMA-effective flows for Boxelder Creek by 16 cfs, as depicted in Figure 7.
SWMM model results are provided in Appendix C.
Figure 7 – SWMM Model Hydrograph for Boxelder Creek at the LWC, Project Design Scenario 1
PEC’s HEC-RAS-generated impacts analysis was based on an idealized trapezoidal channel
conveyance element to carry the projects’ detained runoff to Boxelder Creek. Table 1 below shows
the change in peak flow rates along Boxelder Creek due to the attenuation of stormwater runoff
from the project sites and the resultant increase in flow at the peak in Boxelder Creek.
Joint Outfall Channel Hydraulics Report
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Table 1 SWMM-Predicted 100-year Discharge in Boxelder Creek for Scenario 1
Table
1Cross
Section
Existing
Conditions (cfs)
Scenario 1
(cfs)
31224 (AZ) 2622 2638
31043 (AY) 2511 2527
23235 (AM) 2615 2631
20262 2780 2796
11797 (Y) 2788 2805
11422 (W) 3286 3313
9599 3376 3402
7256 (R) 951 951
These increased flow rates cause a detrimental impact to the floodplain in Lower Boxelder Creek.
The impacts analysis indicated that 100-year water surface elevations would increase between
0.01’ and 0.06’ at various cross sections along the streamline due to the attenuated flow. HEC-RAS
results for the existing conditions (Plan: AB Project) and Scenario 1 (Plan: PC 2024) can be found in
Appendix D.
Results are also depicted in the attached Figure 8, a map which depicts Boxelder Creek HEC-RAS
cross sections in the project vicinity and summarizes both flow and water surface elevations at key
locations. The downstream cross section at Vine Drive (County Road 48) was included as a
representative nearby downstream location. At Vine Drive, the water surface elevation under the
two projects’ developed conditions and Scenario 1, with traditional water quality and quantity
detention, was modeled to be 0.05 feet higher than the base flood. This represents a failure to
demonstrate that the no-rise criterion could be met.
3.4 Scenario 2: Site Detention for Water Quality
The proposed conditions design for Scenario 2 eliminated detention for quantity in on-site storage
that would allow developed discharge conditions to approximate historic conditions and instead
provided detention only for the required storage volumes necessary to satisfy water quality
requirements. This method of site design releases developed site stormwater runoff more quickly
than if it were to be detained and released at a slower rate. The quicker release allows a greater
volume of runoff to be conveyed to the receiving stream system sooner and in advance of the
timing of the peak in the receiving water. This approach is often termed a “beat-the-peak”
solution. In this case, the beat-the-peak approach may allow the non-attenuated outflow to arrive
well before the peak of the Boxelder Creek hydrograph reaches the confluence of the Larimer and
Weld Canal.
The same approach to UDSWMM analysis as defined above was used in Scenario 2. Both projects
were designed to meet water quality criteria, but to allow runoff in excess of the design water
49
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LARIMER AND WELD CANAL
CROSSING STRUCTURE
SIDE SPILL WEIR
BOXELDER CREEK
BOXELDER CREEK
OVERFLOW
FLOODPLAIN HAS BEEN
ELIMINATED BY
AS-BUILT PROJECTS
11263
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31117
31700
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28436
288562869
1
29609
3000
0
273
0
4
10558
8482
7924
10058
9707
9000
272
5
0
3372
0
3247
8
31934
31224
297
8
1
29351
289
8
4
28577
27
7
3
4
2700
6
2681
4
28
1
4
7
331
9
8
328
9
4
31043
4964
49
6
6
49
6
8
49
7
2
4974
4978
498
0
4984
4982
4986
4970
AS
S
O
C
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A
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E
S
45
MA
P
2
FL
O
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6
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,
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5
2
5
(9
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2
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36
6
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,
S
u
i
t
e
1
0
0
C205
29
0 200'400'
SCALE: 1" = 200'
100'
LEGEND:
47768
5062
SURVEY CONTROL NOTES:
4974
EF
F
E
C
T
I
V
E
F
L
O
O
D
P
L
A
I
N
,
EX
.
C
O
N
D
I
T
I
O
N
S
F
L
O
O
D
P
L
A
I
N
,
AN
D
P
R
O
P
O
S
E
D
F
L
O
O
D
P
L
A
I
N
FL
O
O
D
P
L
A
I
N
W
O
R
K
M
A
P
C201
C202
C203
C204
C211
C212 C206
C213
C208 C214
C209 C215
C217
C218
C219
C220
C221
C210
C207
C216
KEYMAP
IN
T
E
R
S
T
A
T
E
2
5
COUNTY RD 54
COUNTY RD 52
CO
U
N
T
Y
R
O
A
D
5
COUNTY ROAD 50
COUNTY RD 48
HIGHWAY 14
E PROSPECT ROAD
LA
R
I
M
E
R
C
O
U
N
T
Y
WE
L
D
C
O
U
N
T
Y
EAST COUNTY ROAD 40E HORSETOOTH ROAD
EAST HARMONY ROAD
EAST COUNTY ROAD 36
IN
T
E
R
S
T
A
T
E
2
5
C201
C202
C203
C204
C211
C212
C213
C208 C214
C209 C215
C217
C218
C219
C220
C221
C210
C206
C207
C216
C205C205
Project Joint Outfall
Channel
Key Cross Sections
31700 - Upstream of Project outfall
31224 - Just downstream of Project outfall
31117 - At north side of LWIC
31043 - At weir
28436 - At CR48/Vine Drive
Figure 8. HEC-RAS Results
Summary, Scenario 1
Note: Peak discharge increased by 16 cfs.
Water surface elevation at Vine Drive
increased by 0.05 feet.
KEYMAP
Joint Outfall Channel Hydraulics Report
11
quality volume to be discharged. For the CPW site, detention was designed to meet infiltration-
focused criteria of the LEED-based design selected by the State for the site. Detention volume was
also provided for the water quality capture volume as defined by the Mile High Flood District. For
the Front Range Storage development, City of Fort Collins Low Impact Development (LID)
requirements were achieved in infiltration-focused design.
As site design developed from preliminary to final, hydrologic analysis of sub-basin 99 was also
refined. Sub-basin 99 was split into eight basins representative of Scenario 2 design specifics:
• Sub-basin 99.1 was defined as representative of CPW Site Basin 101, a 4.5-acre area with
46% impervious cover.
• Sub-basin 99.3 is representative of CPW Site Basins 104-112, a 19.7-acre area with 34%
impervious cover.
• Sub-basin 99.5 is representative of CPW Site Basin 102, a 1.8-acre area with 41%
impervious cover.
• Sub-basin 99.6 is representative of CPW Site Basin 103, a 1.2-acre area with 49%
impervious cover.
• Sub-basin 99.7 is representative of the area west of CPW property, a 13.4-acre area with
24% impervious cover.
• Sub-basin 99.8 is representative of eastern off-site flow that is intercepted by CPW
property, a 6.3-acre area with 2% impervious cover.
• Sub-basin 99.9 is representative of the Front Range Storage development, a 16.4-acre area
with 70% impervious cover.
• Sub-basin 99.4 is representative of land east of the Front Range Storage but also a part of
the property owned by Freedom Storage, Inc., a 40.4-acre area conservatively evaluated
for future industrial development with 80% impervious area.
This runoff scenario did not, of course, achieve a runoff management goal of limiting proposed
outflows to historical release rates, but it abbreviated the hydrograph leaving the project sites and
entering into Boxelder Creek. This acceleration of flow forced the peak outflow rates from the sites
to precede the peak of the hydrograph for Boxelder Creek, which resulted in no increase in the
peak FEMA-effective flows for Boxelder Creek. This is depicted in Figure 9; SWMM model results
are also provided in Appendix C.
Figure 9 shows the timing of the Boxelder Creek hydrograph for the existing conditions (blue),
Scenario 1 (red brown), and Scenario 2 (yellow). The Scenario 1 hydrograph has slightly higher flow
rates during the rising limb but remains higher than the existing conditions through the peak. The
Scenario 2 hydrograph has higher flow rates in the rising limb but equalizes with the existing
conditions as the peak approaches.
Joint Outfall Channel Hydraulics Report
12
Figure 9 – SWMM Model Hydrograph for Boxelder Creek, Scenario 2
The SWMM model for Scenario 2 and the summarized results in Table 2 indicate no change in peak
flow rates along Boxelder Creek due to the more favorable timing of released stormwater: the
quicker release of stormwater runoff from the project sites arrives in advance of the Boxelder
Creek peak.
Table 2 SWMM-Predicted 100-year Discharge in Boxelder Creek for Scenario 2
Table
2Cross
Section
Existing
Conditions (cfs)
Scenario 2
(cfs)
31224 (AZ) 2622 2622
31043 (AY) 2511 2511
23235 (AM) 2615 2615
20262 2780 2780
11797 (Y) 2788 2788
11422 (W) 3286 3286
9599 3376 3376
7256 (R) 951 951
Joint Outfall Channel Hydraulics Report
13
Due to the equivalent flow rates of Scenario 2 with the FEMA-effective flow rates, there is no
impact to the Base Flood Elevations within the Upper or Lower Boxelder Creek in the “beat-the-
peak” scenario. Results are also depicted in the attached Figure 10, a map which depicts Boxelder
Creek HEC-RAS cross sections in the project vicinity and summarizes both flow and water surface
elevations at key locations.
At Vine Drive and for all the cross sections downstream of the joint outfall channel confluence with
Boxelder Creek, the water surface elevation under the two projects conditions and Scenario 2,
with water quantity detention only, the model indicated no change from the base case. This
demonstrates that the no-rise criterion would be met with the development approach. Full HEC-
RAS results for the existing conditions (Plan: AB Project) and Scenario 2 (Plan: PC BTP) can be
found in Appendix D.
4.0 Joint Outfall Channel Design
The joint outfall channel was designed using HEC-RAS 2D modeling methods. HEC-RAS 2D utilizes a
mesh built on top of a terrain layer to calculate flow in all directions. This method is necessary in
the design of the joint outfall channel to ensure that overland flow paths over the proposed site
developments were considered to ensure no site flow can get into the Larimer and Weld Canal.
The HEC-RAS 2D model study area included the project sites, the Larimer and Weld Canal from I-25
to downstream of its confluence with Boxelder Creek, and approximately 100’ of overland flow
areas south of the Larimer and Weld Canal. The base terrain layer used in the model is 2018 1-
meter resolution LiDAR. The study area is shown in Figure 11, and Manning’s values are shown in
Table 3 below.
49
9
0
4982
498
4
4986
49
8
8
49
9
2
49
9
2
50
1
0
50
0
8
50
1
2
50
1
4
50
1
6
50
1
8
49
8
0
49
9
0
50
0
0
49
7
8
49
8
2
49
8
4
49
8
6
49
8
8
49
9
2
49
9
4
49
9
6
49
9
8
50
0
2
50
0
4
4974
49
7
6
49
8
0
49
7
8
49
8
2
49
8
6
4986
4988
49
8
0
49
7
6
49
7
8
49
8
2
49
8
4
49
8
6
49
8
0
49
7
8
498
2
498
4
498
6
49
6
4
49
6
6
49
6
8
4966
4968
LARIM
E
R
A
N
D
W
E
L
D
C
A
N
A
L
IN
T
E
R
S
T
A
T
E
2
5
COUNTY RD 48
BO
X
E
L
D
E
R
C
R
E
E
K
LARIMER AND WELD CANAL
CROSSING STRUCTURE
SIDE SPILL WEIR
BOXELDER CREEK
BOXELDER CREEK
OVERFLOW
FLOODPLAIN HAS BEEN
ELIMINATED BY
AS-BUILT PROJECTS
11263
178
31117
31700
322
0
0
3270
0
334
0
0
33900
26430
28373
28436
288562869
1
29609
3000
0
273
0
4
10558
8482
7924
10058
9707
9000
272
5
0
3372
0
3247
8
31934
31224
297
8
1
29351
289
8
4
28577
27
7
3
4
2700
6
2681
4
28
1
4
7
331
9
8
328
9
4
31043
4964
49
6
6
49
6
8
49
7
2
4974
4978
498
0
4984
4982
4986
4970
AS
S
O
C
I
A
T
E
S
45
MA
P
2
FL
O
O
D
P
L
A
I
N
F
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BO
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6
L
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Dra
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F:\
3
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6
6
4
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3
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3
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4
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,
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6
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C
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0
5
2
5
(9
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2
2
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5
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6
5
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2
,
S
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1
0
0
C205
29
0 200'400'
SCALE: 1" = 200'
100'
LEGEND:
47768
5062
SURVEY CONTROL NOTES:
4974
EF
F
E
C
T
I
V
E
F
L
O
O
D
P
L
A
I
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,
EX
.
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A
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FL
O
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P
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A
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N
W
O
R
K
M
A
P
C201
C202
C203
C204
C211
C212 C206
C213
C208 C214
C209 C215
C217
C218
C219
C220
C221
C210
C207
C216
KEYMAP
IN
T
E
R
S
T
A
T
E
2
5
COUNTY RD 54
COUNTY RD 52
CO
U
N
T
Y
R
O
A
D
5
COUNTY ROAD 50
COUNTY RD 48
HIGHWAY 14
E PROSPECT ROAD
LA
R
I
M
E
R
C
O
U
N
T
Y
WE
L
D
C
O
U
N
T
Y
EAST COUNTY ROAD 40E HORSETOOTH ROAD
EAST HARMONY ROAD
EAST COUNTY ROAD 36
IN
T
E
R
S
T
A
T
E
2
5
C201
C202
C203
C204
C211
C212
C213
C208 C214
C209 C215
C217
C218
C219
C220
C221
C210
C206
C207
C216
C205C205
Project Joint Outfall
Channel
Key Cross Sections
31700 - Upstream of Project outfall
31224 - Just downstream of Project outfall
31117 - At north side of LWIC
31043 - At weir
28436 - At CR48/Vine Drive
Note: Peak discharge and water surface
elevation did not increase.
KEYMAP
Figure 10. HEC-RAS Results
Summary, Scenario 2
Joint Outfall Channel Hydraulics Report
14
Figure 11. Joint Outfall Channel Overview
Table 3 Manning’s n Values for Joint Outfall Channel Design
Table 3
Land Cover Manning's n
Impervious 0.015
Grassland 0.07
Gravel 0.045
Crops 0.06
Open Water 0.03
Grass Swale 0.03
The FEMA-effective hydrology described above was used in the 2D study. The hydrographs for
multiple sub-basins and Boxelder Creek at its intersection point with the study area were applied
to the mesh as inflow boundary conditions. This methodology was used for both the existing
Joint Outfall Channel Hydraulics Report
15
conditions and proposed conditions.
The mesh was shaped with a general 50’ x 50’ cell spacing. Breaklines were added to the mesh to
enforce hydraulically significant terrain features such as curbs and crowns of roadways, high points
and ridgelines in grading, and channel and pond berms. Outflow boundary conditions were created
at the downstream end of the Larimer and Weld Canal and south of the Canal in the overland flow
areas.
The proposed conditions model incorporated the grading plans for the CPW site, the Front Range
Storage development, and the joint outfall channel. The breaklines and mesh were edited to
ensure correct enforcement of hydraulically significant features. Inflow hydrographs were edited
to reflect their proposed conditions flow rates and timing. Both the existing and proposed
conditions models were run with 2-year, 5-year, 10-year, 25-year, and 100-year storm events with
the goal of limiting proposed conditions flows from entering the Larimer and Weld Canal in all
storm events studied.
4.1 Channel Inlet Design
The joint outfall channel will begin south of the access road that separates the CPW site from the
Front Range Storage development. Upstream of the access road there is a “C” shaped swale that
collects runoff from the CPW site and overflow from the I-25 frontage road before delivering it to
the outfall channel via a series of 4 culverts underneath the access road. HY-8 was used to design
this culvert, and HEC-RAS 2D was used to confirm it satisfies the design in the context of the whole
project. The culvert will see a 100-year flow rate of 230 cfs.
The HY-8 design yielded four 36” reinforced concrete pipes. This will limit the overtopping of the
access road to less than 0.5’ at its intersection with the I-25 frontage road. A separate, smaller dry
pond area will be present on the Front Range Storage development immediately to the west of the
beginning of the joint outfall channel. HY-8 results are provided in Appendix E. The pond will
deliver the remainder of the access road overflow to the outfall channel via a culvert underneath
the fire access road on the Front Range Storage development. This second set of culverts will
consist of two 30” reinforced concrete pipes. A small percentage of overflow will still occur out of
this pond and down the ditch on the Front Range Storage development in the 100-year storm, but
it will be directed by site grading toward the project’s rain garden and then to the joint outfall
channel on the south side of the property. Figure 12 shows the upstream channel configuration.
Due to velocity and shear stress in the joint outfall channel downstream of the culverts riprap will
be placed to protect again channel erosion. Maximum velocities at this location will be
approximately 8 fps. According to the United States Army Corps of Engineers (USACE) Engineering
Research Development Center’s (ERDC) “Stability Threshold for Stream Restoration Materials”, 12-
inch D50 riprap will remain stable under the channel inflow conditions downstream of the culverts.
It is recommended that the apron be installed with a thickness of 2.0 feet. See Appendix F for a
table of Permissible Shear and Velocity for Selected Lining Materials, as documented by the USACE
Stability Threshold for Stream Restoration Materials document.
Joint Outfall Channel Hydraulics Report
16
Figure 12. Joint Outfall Channel Inlet Map
4.2 Channel Design
The joint outfall channel was designed using HEC-RAS-generated hydraulic modeling as an open
channel with Manning’s roughness values. SWMM modeling provided 100-year FEMA-effective flow
rates ranging from 230 cfs at the upstream end to 350 cfs at the outlet. All side slopes will be 4:1.
The total channel length will be 3,859 lineal feet, with a fall of 6.1 feet, for an average longitudinal
slope of 0.16%. A minimum freeboard of 1.0 foot will be provided. The channel and banks will be
established with a native grass seed. An estimated 35,000 cubic yards of soil will be excavated to
create the channel. Approximately 30% of that total will be used to create channel berms and the
remaining 70% will be placed on one or both of the project properties.
Figure 13 depicts the flow depths for the joint outfall channel as generated from the HEC-RAS 2D
modeling. Table 4 summarizes design channel geometry, allowing for a 1.0 foot of freeboard above
the maximum flow depth within each channel reach.
Joint Outfall Channel Hydraulics Report
17
Figure 13. Joint Outfall Channel HEC-RAS 2D Model Results
Table 4 Joint Outfall Channel Geometry
Table 4
Channel
Segment
Stations Bottom
Width, ft
Maximum
Flow
Depth, ft
Channel Depth
with Freeboard, ft
Segment Slope,
percent
1 0+00 to 9+80 20 2.7 3.5 0.27
Transition 9+80 to
12+00
2 12+00 to
27+20
30 3.9 5.0 0.11
Transition 27+20 to
27+98
3 27+98 to
36+87
30 4.7 6.0 0.11
Outlet 36+87 to
38+59
Joint Outfall Channel Hydraulics Report
18
Berms will be needed where the channel intersects natural low points in the terrain where runoff
historically drains into the Larimer and Weld Canal. These berms will ensure that the intercepted
flow within the channel is unable to flow into the canal.
4.3 Channel Outlet Design
The joint outfall channel will discharge into Boxelder Creek approximately 200’ upstream of the
Boxelder Creek confluence with the Larimer and Weld Canal. The outfall channel will tie-in to the
west overbank area of the Boxelder Creek at an elevation of 4975.7’. The banks of the outfall
channel will flare out from the channel bottom to tie into existing grade beginning 170’ west of the
top of bank of Boxelder Creek. Due to the shallow nature of the channel (0.1% longitudinal slope)
at the outlet, velocities and shear stresses will be low, but outlet stabilization measures will be
taken to stabilize soil at the outfall.
Channel outfall conditions were analyzed both with Boxelder Creek backwater conditions and
without. The controlling velocities and shear stresses both occur in the no backwater condition.
Maximum velocities within the outfall sit between 2 – 2.5 fps, and maximum shear stresses sit
between 0.3 – 1.00 psf. According to the United States Army Corps of Engineers (USACE)
Engineering Research Development Center’s (ERDC) “Stability Threshold for Stream Restoration
Materials”, a Class B Turf, Long Native Grasses, and 6-inch D50 or greater riprap will all remain
stable under the channel outfall conditions. The outfall will be stabilized with 6-inch D50 soil-filled
riprap at a thickness of 1.0 feet to provide for a stable, vegetated riprap apron. See Appendix F for
a table of Permissible Shear and Velocity for Selected Lining Materials, as documented by the
USACE Stability Threshold for Stream Restoration Materials document.
5.0 Permitting
The recommended design is to construct a new joint outfall channel stretching from the proposed site
developments to the west overbank of Boxelder Creek. The channel will tie-in to Boxelder Creek within the
Boxelder Creek Zone AE floodplain and floodway. Thus, this project falls within Federal, State, and Local
floodplain permitting requirements. This study shows that there will be a “No-Rise” condition within the
Boxelder Creek special flood hazard area, so the floodplain requirements will be limited to State and Local
floodplain development permits.
With the project a Pre-Construction Notification will be submitted to the U.S. Army Corps of Engineers for
a determination whether a USACE Section 404 permit will be required for the outlet of the joint outfall
channel to Boxelder Creek. Construction will be limited to the top of the bank of the Boxelder Creek and
above, so work under an ordinary high-water mark will be limited. It is unknown at this time if the joint
outfall channel will impact jurisdictional wetlands. A draft EA prepared by ERO Resources Corp. will be
submitted with this application.
6.0 Variances
In order to achieve the no-rise criterion for base flood elevations in Boxelder Creek, a beat-the-peak
solution to stormwater management is proposed as detailed herein. This stormwater management
Joint Outfall Channel Hydraulics Report
19
solution, without quantity detention to store developed stormwater conditions to release at historic
conditions, is a variance from City of Fort Collins and Larimer County stormwater criteria. The CPW Site
variance request to Larimer County is included with this application.
7.0 Conclusions
An outfall channel is proposed to convey offsite runoff plus project runoff from the CPW site and the Front
Range Storage development. Stormwater management design for both proposed projects will provide for
required water quality detention. However, quantity detention to reduce developed condition runoff to
approximate historic levels will not be provided. Evaluation of site designs with quantity detention
predicted that the corresponding attenuation of peak flows resulting from quantity detention will create
delayed outfall flows that coincide with peak conditions in the Boxelder Creek. This would result in 16 cfs
of additional flow and 0.06’ rise at downstream cross sections.
The proposed design solution will allow peak flows from the developed sites to reach Boxelder Creek prior
to its peak, resulting in no increases in peak discharge or in water surface elevations. The proposed
channel design will be a flat, grass-lined trapezoidal channel approximately 3,900 feet in length at an
average slope of 0.16 percent and conveying from 230 to 350 cfs in developed site stormwater as well as
offsite runoff from north of Mountain Vista.
8.0 References
[1] “Larimer County Stormwater Design Standards”, Larimer County, Colorado, 2023.
[2] “Fort Collins Stormwater Criteria Manual”, City of Fort Collins, Colorado, September 2018.
[3] Soils Map, “Web Soil Survey 3.0”, USDA Natural Resources Conservation Service (NRCS), April
2023.
[4] Precipitation Frequency Data Server, “NOAA Atlas 14”, National Oceanic and Atmospheric
Administration (NOAA), May 2024.
[5] “Boxelder Creek Hydrology Update”, ICON Engineering, April 2014.
[6] “Boxelder Letter of Map Revision (LOMR)”, Ayres Associates, 2019.
[7] “Stability Threshold for Stream Restoration Materials”, United States Army Corps of Engineers
(USACE) Engineering Research Development Center (ERDC), May 2001.
Appendix A
Larimer and Weld Irrigation Company Correspondence
LAW RENCE CUSTER GRASMICK JONES & DONOVAN, LLP
ATTORNEYS AT LAW
July 11, 2024
Mr. Justin Currie, Planner II
Larimer County Community Development
VIA EMAIL ONLY: curriejp@co.larimer.co.us
RE: Colorado Parks and Wildlife- Office Relocation-Project Case # INQ4880/ 23-
ZONE3544 – Comments
Dear Justin,
Our firm represents the Larimer and Weld Irrigation Company (“LWIC”), the owner of the
Larimer and Weld Canal (the “Canal”) and associated water rights diverted and carried therein.
LWIC learned inadvertently of CPW’s plans as cited above to relocate its office, widen the I-25
Frontage Road, and discharge increased amounts of stormwater into the Canal. LWIC is highly
concerned that it will be at the mercy of future developments which plan to increase their
stormwater discharge into the Canal, chiefly due to your failure to inform us of that possibility.
Once your office has approved the plans, LWIC’s only recourse would be to sue in court well after
the infrastructure has been installed, and perhaps well after damage has occurred. Your response
to LWIC dated June 24, 2024 indicated that Larimer County only informs ditch companies when
“the ditch is located on the property, directly adjacent to the property, or if they are proposing a
crossing. In this case I did not include you as a referral agency since your ditch is hundreds of feet
away.” The number of feet the stormwater must travel before entering our Canal is irrelevant.
Instead, the very fact that CPW (or another developer) plans to increase its discharge into the Canal
triggers your duty to inform LWIC of that proposal, afford it the opportunity to comment thereon,
and ascertain if the required approval from the ditch company is forthcoming.
You may not be aware of the issues stormwater causes any ditch company. Not only must the ditch
company be able to maintain the capacity to convey its adjudicated water rights to its shareholders
for irrigation use, it must be able to do so safely. Increased amounts of stormwater entering our
ditch from increased development along the Canal raise safety, maintenance and operational issues
for the ditch company. In addition, the Colorado Division of Water Resources has informed us
that stormwater collected and discharged by a detention facility into the Larimer and Weld
irrigation system may not be beneficially used and is considered to be an out of priority inflow,
and as such would need to be passed through our system without use and released to the stream.
Any such increased discharge into our Canal may impose an undue burden upon the ditch company
for administration (i.e, staffing, additional infrastructure, tracking, measuring, reporting). There is
no easy way to differentiate stormwater flows from the irrigation water owed to shareholders.
Further, LWIC has no structure to discharge stormwater from its Canal into a stream. These are all
5245 Ronald Reagan Blvd., Suite 1
Johnstown, COLORADO 80534
TELEPHONE: 970-622-8181
www.LCWATERLaw.com
linda@lcwaterlaw.com
Bradley C. Grasmick • David P. Jones • Ryan M. Donovan • Wesley S. Knoll • Richard T. LiPuma (Of Counsel)
David L. Strait • Linda Preslan Bower • Jacklyn P. Gunn • Nicholas P. Espenan
issues which the ditch company does not consider to be its financial or legal responsibility which
would require discussion with any developer. Needless to say, the company can only do so when
it is aware that any owner plans to increase its stormwater flows, and for that, we require your
cooperation in informing us.
With regard to CPW’s Case #INQ4880, LWIC’s review is ongoing, specifically related to the
Applicant’s proposal to discharge increased stormwater into the Canal. Please see the attached
Technical Review from W.W. Wheeler & Associates, Inc. which contains substantive comments
and concerns about the current plans. LWIC does not presently approve of the stormwater
discharge plans, including the potential for a storm event to overtop the planned filtration basins
for aquatic nuisance invasive species washout stations. The potential for such invasive species
entering the Canal and being transported via the extensive network of ditches and reservoirs
throughout northeast Colorado would be catastrophic for the interests of all parties.
Applicant’s Hydraulic Report indicates cooperation on easement issues with their neighbors to the
south, believed to be Front Range Storage. LWIC has also been consulting with Front Range
Storage on their own improvement plans. Front Range Storage may have drainage issues similar
to CPW’s. It is possible that CPW and Front Range Storage may find some mutual benefit in
discussing a cooperative effort on discharging increased stormwater to the natural drainage in ways
that will not adversely impact the Canal, and we encourage that cooperation.
We note that Section 1.2 of the County Design Standards states that any policies or criteria not
specifically addressed in the County Standards shall follow the Mile High Flood District Urban
Storm Drainage Criteria manual. While we did not find much specific reference in the County
Standards regarding discharges to irrigation ditches, at least two sections of the Mile High Criteria
strongly discourage use of irrigation diches for flood mitigation purposes or for collection and
transport of initial or major storm runoff. See Sections 3.4.3 and 4.4 of USDCM Volume 1. Even
if such use were considered, written approval of the ditch owner is required. LWIC has not given
any such approval to the current application. Please modify your general criteria for referral
agencies to include the relevant dich companies for any application which would increase
stormwater flows into an irrigation ditch or reservoir.
Thank you for your consideration of LWIC’s concerns, including those in the Wheeler Technical
Review attached. Applicant’s engineer is free to contact Hayden Strickland with Wheeler to
discuss LWIC’ s requirements for approval.
Sincerely,
LAWRENCE CUSTER GRASMICK JONES & DONOVAN, LLP
__________________________________________
Linda P. Bower, Esq.
Enc.: Wheeler Technical Review
Cc. Kimberly Nelson, LWIC
Kent Bruxvoort
July 9, 2024
Kimberly Nelson
Larimer and Weld Irrigation Company
106 Elm Avenue
Eaton, CO 80615
RE: Colorado Parks and Wildlife - Office Relocation & I-25 Frontage Road
Improvements - Project Case # INQ4880
Dear Kimberly:
As requested by Larimer and Weld Irrigation Company (LWIC), we have reviewed the Colorado
Parks and Wildlife (CPW) Office Relocation and I-25 Frontage Road Improvements, (Larimer
County Project Case No. INQ4880), and are providing our comments. CPW is proposing to
develop approximately 27.2 acres of land located at 1424 NE Frontage Road, Fort Collins, CO
80524, in Larimer County. Figure 1 presents a vicinity map from the CPW site drawings.
Figure 1 – Vicinity Map depicting project location.
CPW is seeking to develop the land to include the following:
A two-story administration building
Kimberly Nelson, LWIC.
June 14, 2024
Page 2
Seven storage buildings
0.42 acres of gravel pavement not accessible by the public for vehicle traffic and storage,
and
8.38 acres of pavement for public parking, CPW staff parking areas, and associated
driveways.
LWIC owns and operates the Larimer and Weld Canal (LWC) which is located south of the
proposed development. The LWC delivers irrigation water to Company Shareholders who irrigate
lands in Larimer and Weld Counties.
Wheeler reviewed the following documents:
1. Colorado Parks and Wildlife Fort Collins Relocation Civil Construction Plans, 1626 NE
Frontage Road Fort Collins, CO, 80524, Professional Engineering Consultants, April 26,
2024, 76 Pages.
2. Colorado Parks and Wildlife Office Relocation Project Description, Project Case #
INQ4880, Russell & Mills, August 18, 2023, 5 Pages.
3. Preliminary Drainage Report for Fort Collins Office Relocation, State of Colorado,
Colorado Parks and Wildlife, Larimer County, Colorado. Professional Engineering
Consultants, May 2024, 47 Pages.
4. CDOT Hydraulics Report for Colorado Parks and Wildlife Fort Collins Office Relocations ,
I-25 Frontage Road Improvements, Larimer County, Colorado, Professional Engineering
Consultants, May 2024, 49 Pages.
Wheeler’s comments regarding potential water-related issued associated with the project are as
follows:
1. LWIC does not allow a change to the historical quantity, quality, type, rate, or location of
water draining into the LWC. With these restrictions in mind, Wheeler has the following
comments regarding the project:
a. The Preliminary Drainage Report indicates that the pre-development stormwater
runoff during the 100-year storm is 2.9 acre-feet, while the proposed development
conditions would generate 4.30 acre-feet of stormwater runoff. This water would
discharge from the detention pond into the borrow ditch along I-25 and then into
the LWC. LWIC does not allow an increase in the volume of stormwater entering
the LWC.
b. The Civil Construction Plans show two invasive species washout stations located
on the developed property. LWIC is concerned that water from these filtration
basins could enter the ditch during a storm event. This is a change to the historical
water quality of water entering the LWC, which is not allowed by LWIC.
Additionally, should invasive species enter the LWC it would cause significant
Kimberly Nelson, LWIC.
June 14, 2024
Page 3
damage to the LWIC infrastructure and downstream reservoirs impacting the ability
to make irrigation deliveries. Please provide an analysis showing that water
discharged from these washout stations physically cannot reach the LWC under
any circumstances.
c. The CDOT Hydraulics Report indicates that the increased runoff generated from
improving the I-25 Frontage Road will increase the historical flow rate from 1.7
cubic feet per second (cfs) under the current conditions to 2.5 cfs under the
proposed conditions. This water would drain directly to the LWC. This increase in
historical rate of discharge to the LWC is not acceptable. Even if a detention basis
is constructed to reduce the flow rate, LWIC will not allow for an increase in volume
of water discharged to the canal.
d. The Preliminary Drainage Report indicates that the spillway for the detention pond
will be capable of passing 76.4 cfs. Does this flow enter the LWC? Please provide
a map showing its flow path and ultimate destination.
2. The CDOT Hydraulics Report states that the 2019 LOMR removed the subject property
from the flood plain due to the construction of the East Side Detention Facility. Similarly,
the Preliminary Drainage Report indicates that the developed lands are no longer in the
floodplain of Box Elder Creek due to the construction of the East Side Detention Facility.
However, it appears that up to 274 cfs may flow into the frontage road borrow ditch, or into
the developed property. Please provide more details on how and where this flow occurs,
and what its ultimate discharge location is. If the historical location or manner of discharge
changes because of this project, LWIC will not allow this water to be discharged into the
LWC.
Wheeler recommends that CPW address these issues before LWIC provides any notice of
acceptance to Larimer County. The issues identified above are based on the data and documents
which were provided to Wheeler for review and may change as additional information becomes
available.
Sincerely,
W. W. Wheeler & Associates, Inc.
Hayden Strickland, P.E.
Cc via Email: Autumn Penfold, LWIC
Andy Pineda, LWIC
Linda Bower, Lawrence Custer Grasmick Jones & Donovan, LLP
Ryan Donovan, Lawrence Custer Grasmick Jones & Donovan, LLP
File Location: R:\1900\1953-LWIC\05_CPW Building\7_Documents\06-13-24 CPW Comments.docx
1
Kent Bruxvoort
From:Autumn Penfold <apenfold@eatonditch.com>
Sent:Tuesday, February 4, 2025 2:20 PM
To:Kent Bruxvoort; Kim Nelson; ryan@lcwaterlaw.com; linda@lcwaterlaw.com;
hayden.strickland@wwwheeler.com
Cc:Nicholas Raley; Barker - DNR, Paul; Joey Frank; Shawn Krier - DNR; Andrew Martin
Subject:RE: Colorado Parks and Wildlife Fort Collins Office Relocation, update on outfall channel
design
Thank you for the update, Kent. We’ll look for more information from you as the stormwater piece of your project
develops.
Autumn Penfold
Larimer & Weld Irrigation Companies
106 Elm Avenue • Eaton, CO 80615
970.454.3377 (office) • 970.454.0154 (fax)
www.eatonditch.com
Privileged & Confidential: This communication, including attachments, is for the exclusive use of the addressee and may contain proprietary,
confidential and/or privileged information. If you are not the intended recipient, any use, copying, disclosure, dissemination or distribution is strictly
prohibited. If you are not the intended recipient, please notify the sender immediately by return e-mail, delete this communication and destroy all
copies.
From: Kent Bruxvoort <kent.bruxvoort@pec1.com>
Sent: Thursday, January 16, 2025 8:48 AM
To: Autumn Penfold <apenfold@eatonditch.com>; Kim Nelson <knelson@eatonditch.com>; ryan@lcwaterlaw.com;
linda@lcwaterlaw.com; hayden.strickland@wwwheeler.com
Cc: Nicholas Raley <nicholas.raley@pec1.com>; Barker - DNR, Paul <paul.barker@state.co.us>; Joey Frank
<jfrank@jrengineering.com>; Shawn Krier - DNR <shawn.krier@state.co.us>; Andrew Martin
<amartin@d2carchitects.com>
Subject: Colorado Parks and Wildlife Fort Collins Office Relocation, update on outfall channel design
Greetings Autumn and team,
As you know, we have been working with Larimer County regarding our site plan submittal for Colorado Parks and
Wildlife’s (CPW’s) O"ice Relocation project. The relocation site is highlighted in the screen shot below, at the SE
corner of the I-25/Mountain Vista interchange. I’m sending this email as an update on stormwater planning and
design and in partial response to comments provided by Larimer and Weld Irrigation Company. We are not
requesting action at this time—this email is intended to keep your team in the loop.
2
Our project’s drainage report originally proposed stormwater detention in accordance with County criteria, stored
and released to the roadside swale for the SE I-25 frontage road. From there the water would ultimately discharge
into the Larimer and Weld Canal, owned by the Larimer and Weld Irrigation Company (LWIC). LWIC stated they
wouldn’t accept the water, and we’ve been working to address the situation over the last several months. Here’s
where we currently stand:
1. The State CPW has coordinated with and reached general agreement with the property owners to the south
of us, the Kelleys. The Kelleys are proposing a mini-storage project through Fort Collins’ process and face
the same stormwater management issue that the CPW does. The Kelleys have contracted with JR
Engineering for site design, and PEC has been coordinating the solution to the shared problem with JR’s
PM, Joey Frank, and his team.
2. The 2 parties and their consultants are working together on a joint outfall channel that would collect and
convey stormwater through the Kelleys’ property to Boxelder Creek.
3. We’ve been given copies of the various SWMM and HEC-RAS models that have been used by the Boxelder
Stormwater Authority so that we could incorporate these 2 properties and the proposed outfall channel in
the models.
4. We met with Matt Simpson representing City of Fort Collins Stormwater in December and presented the
preliminary model findings to him. The chief issue we were finding is that in conveying water directly to
Boxelder Creek, instead of into the LWIC and spilling to the Creek, we were marginally increasing the
channel discharge. This of course resulted in marginally increasing the water surface elevations in
Boxelder Creek all the way downstream to its confluence with the Poudre. This would lead us toward the
FEMA Letter of Map Revision (LOMR) process.
5. We haven’t fully vetted this option yet, but it appears to us that the only viable solution to avoid the
complication, cost and delay of the LOMR process is for both properties to beat the timing of the Boxelder
peak discharge during the 100-year design event with limited on-site detention provided for water quality,
3
LID, and LEED/infiltration purposes and earlier discharge through the outfall channel to the Creek. This
would eliminate much of the volume of on-site detention ordinarily provided to attenuate the
development’s peak discharge to historic levels.
6. We’re close to being able to share with the County and the City our concept channel design, complete with
the HEC-RAS modeling, to demonstrate the projects’ combined impacts on the flood hydrograph in
Boxelder Creek.
7. With general acknowledgement from the agencies that this solution has merit, we will submit again to
Larimer County for Site Plan approval.
8. Hopefully this update is helpful. If LWIC believes meeting together to discuss our approach is a good idea,
we would be please to meet with your team.
As we continue to progress toward our stormwater management solution we will continue to communicate at key
milestones with LWIC.
Best regards,
-Kent
Kent Bruxvoort , PE
Team Lead | Fort Collins Civil Engineering
kent.bruxvoort@pec1.com
800.754.2691 | C 970.342.0428
351 Linden St | Ste 100 | Fort Collins, CO 80524
Professional Engineering Consultants
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Appendix B
Pertinent Sections; 2019 LOMR and 2014 Boxelder Creek Basin Flood Study
Ayres Associates
Table 5.6 Larimer-Weld Canal model (HEC-RAS) Inflows from the EPASWMM model
Node
(Ditch Inflow
HEC-RAS Cross
Section
(EPA SWMM Hydrograph
Peak Flow Into Ditch (cfs)
Existing
Conditions
(Ayres 2015/2018)
(Ayres 2018)
Difference
903 21990-20950
901 20080
902 19405-17985
904 15360-14550
907 13415
913 11756
914 11615-10600
917 10230-9025
916 8210
919 6075-4950
922 4950-195
Table 5.7 Larimer- Weld Canal HEC-RAS model spills (outflows) to EPA SWMM model.
Lateral Weir
(Spill Outflow
HEC-RAS
Storage Area
(Spill from
Spill
Location on
Figure
Node
(Inflow from
Peak Flow Out of Ditch (cfs)
Existing
Conditions
(Ayres 2015/2018)
(Ayres 2018)
Difference
The L&W spills were updated in the As-Built Project EPA SWMM model. The L&W spill
hydrographs are inserted at nodes 905, 906, 909, 912, 915, 918, 921, and 924 in the EPA
SWMM model.
• Diversion 925: In the existing conditions (pre-project), Boxelder Creek was currently
conveyed under I-25 through two (2) box culverts. These two (2) box culverts did not have
the capacity to convey the entire 100-year event and therefore a spill to the south occurred
at the existing box culverts. This spill was modeled in the Existing Condition EPA SWMM
model at diversion node 925. One of the projects included in this LOMR opened the other
two (2) I-25 box culverts which had previously been blocked off. Due to the increased
capacity of all four (4) box culverts and the reduced 100-yr discharge from ESDF
detention, the flow spill to the south has been eliminated. This diversion element was
converted in the SWMM model to a standard junction element.
Appendix C
SWMM Model Results
EXISTING CONDITIONS
PC SWMM LAYOUT
Node 916. Boxelder
Creek, at confluence
with Larimer & Weld
Canal
PROPOSED CONDITIONS - SCENARIO 1
PC SWMM LAYOUT
CPW Site, with
detention for quantity
and quality
Front Range Storage
development, with
detention for quantity
and quality
Boxelder Creek, at
confluence with
Larimer & Weld Canal
Note: Scenario 1 is
standard stormwater
detention for water
quality and to attenuate
peak developed
discharge to historical
conditions.
PROPOSED CONDITIONS - SCENARIO 2
PC SWMM LAYOUT
CPW Site, with
detention for water
quality only
Front Range Storage
development, with
detention water
quality only
Boxelder Creek, at
confluence with
Larimer & Weld Canal
Note: Scenario 2 is the
beat-the-peak
alternative with
stormwater detention
for water quality and
LEED/LID criteria.
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/28/2013 0:01 0.0 0.0 0.0
1/28/2013 0:11 0.0 0.0 0.0
1/28/2013 0:21 0.0 0.0 0.0
1/28/2013 0:31 0.0 0.0 0.0
1/28/2013 0:41 0.0 0.0 0.0
1/28/2013 0:51 0.0 0.0 0.0
1/28/2013 1:01 0.0 0.0 0.0
1/28/2013 1:11 0.0 0.0 0.0
1/28/2013 1:21 0.0 0.0 0.0
1/28/2013 1:31 0.0 0.0 0.0
1/28/2013 1:41 0.0 0.0 0.0
1/28/2013 1:51 0.0 0.0 0.0
1/28/2013 2:01 0.0 0.0 0.0
1/28/2013 2:11 0.0 0.0 0.0
1/28/2013 2:21 0.0 0.0 0.0
1/28/2013 2:31 0.0 0.0 0.0
1/28/2013 2:41 0.0 0.0 0.0
1/28/2013 2:51 0.0 0.0 0.0
1/28/2013 3:01 0.0 0.0 0.0
1/28/2013 3:11 0.0 0.0 0.0
1/28/2013 3:21 0.0 0.0 0.0
1/28/2013 3:31 0.0 0.0 0.0
1/28/2013 3:41 0.0 0.0 0.0
1/28/2013 3:51 0.0 0.0 0.0
1/28/2013 4:01 0.0 0.0 0.0
1/28/2013 4:11 0.0 0.0 0.0
1/28/2013 4:21 0.0 0.1 0.1
1/28/2013 4:31 0.1 0.1 0.1
1/28/2013 4:41 0.1 0.5 0.5
1/28/2013 4:51 0.4 0.9 0.9
1/28/2013 5:01 0.9 1.6 1.6
1/28/2013 5:11 1.8 1.7 1.7
1/28/2013 5:21 2.1 2.0 2.0
1/28/2013 5:31 2.2 2.3 2.3
1/28/2013 5:41 2.2 2.2 2.2
1/28/2013 5:51 2.4 2.2 2.2
1/28/2013 6:01 2.2 2.2 2.2
1/28/2013 6:11 2.1 2.1 2.1
1/28/2013 6:21 9.0 12.3 10.5
1/28/2013 6:31 12.3 44.7 29.2
1/28/2013 6:41 188.5 299.7 131.5
1/28/2013 6:51 502.9 889.3 509.3
1/28/2013 7:01 655.2 1015.8 688.5
1/28/2013 7:11 619.5 950.5 654.8
Page 1
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/28/2013 7:21 623.9 942.2 658.0
1/28/2013 7:31 775.5 1084.1 937.9
1/28/2013 7:41 971.2 1269.2 1221.5
1/28/2013 7:51 1119.9 1402.9 1366.6
1/28/2013 8:01 1209.8 1475.7 1442.9
1/28/2013 8:11 1256.3 1501.7 1472.6
1/28/2013 8:21 1252.0 1468.2 1449.0
1/28/2013 8:31 1247.6 1433.8 1422.6
1/28/2013 8:41 1254.6 1413.3 1406.5
1/28/2013 8:51 1270.8 1402.7 1400.5
1/28/2013 9:01 1297.1 1407.3 1407.1
1/28/2013 9:11 1338.2 1428.0 1429.5
1/28/2013 9:21 1397.7 1471.2 1473.1
1/28/2013 9:31 1465.5 1523.5 1527.1
1/28/2013 9:41 1537.4 1584.2 1588.2
1/28/2013 9:51 1610.6 1645.8 1651.8
1/28/2013 10:01 1680.2 1704.3 1717.3
1/28/2013 10:11 1745.9 1762.0 1782.8
1/28/2013 10:21 1808.6 1819.3 1845.2
1/28/2013 10:31 1873.9 1881.1 1910.1
1/28/2013 10:41 1942.8 1947.6 1978.4
1/28/2013 10:51 2012.4 2016.1 2047.9
1/28/2013 11:01 2075.1 2077.9 2110.1
1/28/2013 11:11 2134.5 2136.6 2169.1
1/28/2013 11:21 2191.6 2193.3 2225.8
1/28/2013 11:31 2245.2 2246.6 2279.0
1/28/2013 11:41 2295.0 2296.2 2328.3
1/28/2013 11:51 2337.5 2338.5 2370.4
1/28/2013 12:01 2374.2 2375.0 2406.6
1/28/2013 12:11 2406.1 2406.8 2438.0
1/28/2013 12:21 2433.9 2434.5 2465.4
1/28/2013 12:31 2458.8 2459.3 2489.7
1/28/2013 12:41 2481.0 2481.5 2511.5
1/28/2013 12:51 2501.1 2501.5 2531.0
1/28/2013 13:01 2519.0 2519.4 2548.5
1/28/2013 13:11 2535.2 2535.6 2564.2
1/28/2013 13:21 2549.8 2550.2 2578.3
1/28/2013 13:31 2563.0 2563.3 2591.0
1/28/2013 13:41 2574.7 2574.9 2602.1
1/28/2013 13:51 2584.9 2585.1 2611.8
1/28/2013 14:01 2593.7 2593.9 2620.0
1/28/2013 14:11 2601.3 2601.4 2627.0
1/28/2013 14:21 2607.5 2607.7 2632.7
1/28/2013 14:31 2612.6 2612.8 2636.4
Page 2
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/28/2013 14:41 2616.5 2616.6 2637.6
1/28/2013 14:51 2619.3 2619.4 2638.2
1/28/2013 15:01 2621.0 2621.1 2638.1
1/28/2013 15:11 2621.7 2621.9 2637.3
1/28/2013 15:14 2621.8 2621.9 2636.9
1/28/2013 15:21 2621.5 2621.6 2635.7
1/28/2013 15:31 2620.4 2620.5 2633.5
1/28/2013 15:41 2618.4 2618.5 2630.6
1/28/2013 15:51 2615.7 2615.8 2627.1
1/28/2013 16:01 2612.2 2612.3 2622.9
1/28/2013 16:11 2608.0 2608.1 2618.1
1/28/2013 16:21 2603.2 2603.2 2612.8
1/28/2013 16:31 2597.7 2597.8 2606.9
1/28/2013 16:41 2591.7 2591.7 2600.6
1/28/2013 16:51 2585.1 2585.2 2593.7
1/28/2013 17:01 2578.0 2578.1 2586.3
1/28/2013 17:11 2570.4 2570.5 2578.4
1/28/2013 17:21 2562.3 2562.4 2570.1
1/28/2013 17:31 2553.8 2553.8 2561.3
1/28/2013 17:41 2544.9 2544.9 2552.3
1/28/2013 17:51 2535.6 2535.6 2542.8
1/28/2013 18:01 2526.0 2526.0 2533.1
1/28/2013 18:11 2516.0 2516.0 2522.9
1/28/2013 18:21 2505.6 2505.6 2512.4
1/28/2013 18:31 2494.9 2494.9 2501.6
1/28/2013 18:41 2483.9 2483.9 2490.6
1/28/2013 18:51 2472.6 2472.6 2479.2
1/28/2013 19:01 2461.1 2461.1 2467.7
1/28/2013 19:11 2449.5 2449.5 2456.0
1/28/2013 19:21 2437.7 2437.7 2444.1
1/28/2013 19:31 2425.8 2425.8 2432.1
1/28/2013 19:41 2413.7 2413.7 2420.0
1/28/2013 19:51 2401.4 2401.5 2407.7
1/28/2013 20:01 2388.9 2388.9 2395.2
1/28/2013 20:11 2376.2 2376.2 2382.4
1/28/2013 20:21 2363.2 2363.3 2369.5
1/28/2013 20:31 2350.3 2350.3 2356.5
1/28/2013 20:41 2336.9 2336.9 2343.0
1/28/2013 20:51 2322.3 2322.4 2328.3
1/28/2013 21:01 2307.3 2307.3 2313.0
1/28/2013 21:11 2291.9 2292.0 2297.5
1/28/2013 21:21 2276.5 2276.6 2281.8
1/28/2013 21:31 2260.7 2260.7 2265.7
1/28/2013 21:41 2244.6 2244.6 2249.3
Page 3
HYDROGRAPH PEAK
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/28/2013 21:51 2228.3 2228.3 2232.8
1/28/2013 22:01 2211.8 2211.8 2216.1
1/28/2013 22:11 2195.1 2195.2 2199.2
1/28/2013 22:21 2178.2 2178.2 2182.0
1/28/2013 22:31 2161.1 2161.1 2164.7
1/28/2013 22:41 2143.8 2143.9 2147.3
1/28/2013 22:51 2126.5 2126.5 2129.7
1/28/2013 23:01 2109.1 2109.1 2112.2
1/28/2013 23:11 2091.6 2091.6 2094.5
1/28/2013 23:21 2074.2 2074.1 2076.9
1/28/2013 23:31 2055.7 2055.7 2058.3
1/28/2013 23:41 2034.7 2034.7 2037.2
1/28/2013 23:51 2012.6 2012.6 2014.9
1/29/2013 0:01 1990.0 1990.0 1992.2
1/29/2013 0:11 1966.7 1966.7 1968.8
1/29/2013 0:21 1942.5 1942.6 1944.6
1/29/2013 0:31 1917.9 1917.9 1919.8
1/29/2013 0:41 1892.9 1892.9 1894.7
1/29/2013 0:51 1867.5 1867.5 1869.3
1/29/2013 1:01 1841.8 1841.8 1843.5
1/29/2013 1:11 1816.1 1816.0 1817.6
1/29/2013 1:21 1789.3 1789.3 1790.9
1/29/2013 1:31 1760.5 1760.5 1762.0
1/29/2013 1:41 1730.4 1730.4 1731.8
1/29/2013 1:51 1699.2 1699.2 1700.6
1/29/2013 2:01 1665.8 1665.9 1667.1
1/29/2013 2:11 1631.1 1631.2 1632.4
1/29/2013 2:21 1595.7 1595.7 1596.9
1/29/2013 2:31 1559.7 1559.7 1560.9
1/29/2013 2:41 1523.2 1523.1 1524.2
1/29/2013 2:51 1484.1 1484.2 1485.2
1/29/2013 3:01 1439.3 1439.4 1440.4
1/29/2013 3:11 1389.6 1389.7 1390.7
1/29/2013 3:21 1334.4 1334.4 1335.3
1/29/2013 3:31 1274.2 1274.3 1275.2
1/29/2013 3:41 1203.7 1203.8 1204.7
1/29/2013 3:51 1125.9 1126.0 1126.9
1/29/2013 4:01 1044.8 1044.8 1045.7
1/29/2013 4:11 965.8 965.9 966.7
1/29/2013 4:21 890.3 890.3 891.1
1/29/2013 4:31 820.5 820.5 821.3
1/29/2013 4:41 762.6 762.5 763.2
1/29/2013 4:51 720.8 720.6 721.4
1/29/2013 5:01 693.7 693.5 694.2
Page 4
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/29/2013 5:11 677.1 676.9 677.6
1/29/2013 5:21 667.0 666.9 667.6
1/29/2013 5:31 660.6 660.6 661.2
1/29/2013 5:41 656.1 656.0 656.7
1/29/2013 5:51 652.4 652.4 653.0
1/29/2013 6:01 649.3 649.3 649.9
1/29/2013 6:11 646.3 646.3 646.9
1/29/2013 6:21 643.5 643.5 644.1
1/29/2013 6:31 640.7 640.8 641.3
1/29/2013 6:41 638.1 638.1 638.6
1/29/2013 6:51 635.4 635.4 636.0
1/29/2013 7:01 632.8 632.8 633.3
1/29/2013 7:11 630.2 630.2 630.7
1/29/2013 7:21 627.6 627.6 628.2
1/29/2013 7:31 625.1 625.1 625.6
1/29/2013 7:41 622.6 622.6 623.1
1/29/2013 7:51 620.2 620.2 620.7
1/29/2013 8:01 617.8 617.8 618.3
1/29/2013 8:11 615.5 615.5 616.0
1/29/2013 8:21 613.2 613.2 613.7
1/29/2013 8:31 610.9 610.9 611.4
1/29/2013 8:41 608.7 608.7 609.2
1/29/2013 8:51 606.5 606.5 607.0
1/29/2013 9:01 604.4 604.4 604.9
1/29/2013 9:11 602.3 602.3 602.8
1/29/2013 9:21 600.2 600.2 600.7
1/29/2013 9:31 598.1 598.1 598.6
1/29/2013 9:41 596.0 596.0 596.5
1/29/2013 9:51 594.0 594.0 594.4
1/29/2013 10:01 591.9 591.9 592.4
1/29/2013 10:11 589.9 589.9 590.4
1/29/2013 10:21 587.9 587.9 588.4
1/29/2013 10:31 586.0 586.0 586.4
1/29/2013 10:41 584.1 584.1 584.5
1/29/2013 10:51 582.2 582.2 582.6
1/29/2013 11:01 580.3 580.3 580.8
1/29/2013 11:11 578.5 578.5 579.0
1/29/2013 11:21 576.7 576.7 577.1
1/29/2013 11:31 574.9 574.9 575.3
1/29/2013 11:41 573.1 573.1 573.5
1/29/2013 11:51 571.3 571.3 571.8
1/29/2013 12:01 569.5 569.5 570.0
1/29/2013 12:11 567.8 567.8 568.2
1/29/2013 12:21 566.0 566.0 566.5
Page 5
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/29/2013 12:31 564.3 564.3 564.7
1/29/2013 12:41 562.6 562.6 563.0
1/29/2013 12:51 560.9 560.9 561.3
1/29/2013 13:01 559.2 559.2 559.6
1/29/2013 13:11 557.5 557.5 558.0
1/29/2013 13:21 555.9 555.9 556.3
1/29/2013 13:31 554.2 554.2 554.7
1/29/2013 13:41 552.6 552.6 553.1
1/29/2013 13:51 551.1 551.1 551.5
1/29/2013 14:01 549.6 549.6 550.0
1/29/2013 14:11 548.1 548.1 548.6
1/29/2013 14:21 546.8 546.8 547.2
1/29/2013 14:31 545.6 545.6 546.0
1/29/2013 14:41 544.5 544.5 544.9
1/29/2013 14:51 543.5 543.5 543.9
1/29/2013 15:01 542.6 542.6 543.0
1/29/2013 15:11 541.8 541.8 542.2
1/29/2013 15:21 541.0 541.0 541.4
1/29/2013 15:31 540.4 540.4 540.8
1/29/2013 15:41 539.8 539.8 540.2
1/29/2013 15:51 539.2 539.2 539.6
1/29/2013 16:01 538.7 538.7 539.1
1/29/2013 16:11 538.2 538.2 538.6
1/29/2013 16:21 537.8 537.8 538.2
1/29/2013 16:31 537.3 537.3 537.7
1/29/2013 16:41 536.9 536.9 537.3
1/29/2013 16:51 536.5 536.5 536.9
1/29/2013 17:01 536.1 536.1 536.5
1/29/2013 17:11 535.7 535.7 536.1
1/29/2013 17:21 535.3 535.3 535.7
1/29/2013 17:31 534.9 534.9 535.3
1/29/2013 17:41 534.5 534.5 534.8
1/29/2013 17:51 534.0 534.1 534.4
1/29/2013 18:01 533.6 533.6 534.0
1/29/2013 18:11 533.2 533.2 533.6
1/29/2013 18:21 532.8 532.8 533.2
1/29/2013 18:31 532.4 532.4 532.8
1/29/2013 18:41 532.0 532.0 532.4
1/29/2013 18:51 531.6 531.6 532.0
1/29/2013 19:01 531.2 531.2 531.6
1/29/2013 19:11 530.8 530.8 531.2
1/29/2013 19:21 530.4 530.4 530.8
1/29/2013 19:31 530.0 530.0 530.4
1/29/2013 19:41 529.6 529.6 530.0
Page 6
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/29/2013 19:51 529.2 529.2 529.6
1/29/2013 20:01 528.8 528.8 529.2
1/29/2013 20:11 528.4 528.4 528.8
1/29/2013 20:21 528.0 528.0 528.3
1/29/2013 20:31 527.6 527.6 527.9
1/29/2013 20:41 527.2 527.2 527.5
1/29/2013 20:51 526.8 526.8 527.1
1/29/2013 21:01 526.4 526.4 526.7
1/29/2013 21:11 526.0 526.0 526.4
1/29/2013 21:21 525.6 525.6 526.0
1/29/2013 21:31 525.3 525.3 525.6
1/29/2013 21:41 525.0 525.0 525.3
1/29/2013 21:51 524.7 524.7 525.0
1/29/2013 22:01 524.4 524.4 524.7
1/29/2013 22:11 524.1 524.1 524.4
1/29/2013 22:21 523.9 523.9 524.2
1/29/2013 22:31 523.6 523.6 523.9
1/29/2013 22:41 523.4 523.4 523.7
1/29/2013 22:51 523.1 523.1 523.5
1/29/2013 23:01 522.9 522.9 523.2
1/29/2013 23:11 522.7 522.7 523.0
1/29/2013 23:21 522.5 522.5 522.8
1/29/2013 23:31 522.2 522.2 522.6
1/29/2013 23:41 522.0 522.0 522.3
1/29/2013 23:51 521.8 521.8 522.1
1/30/2013 0:01 521.6 521.6 521.9
1/30/2013 0:11 521.3 521.3 521.7
1/30/2013 0:21 521.1 521.1 521.4
1/30/2013 0:31 520.9 520.9 521.2
1/30/2013 0:41 520.7 520.7 521.0
1/30/2013 0:51 520.5 520.5 520.8
1/30/2013 1:01 520.2 520.2 520.6
1/30/2013 1:11 520.0 520.0 520.3
1/30/2013 1:21 519.8 519.8 520.1
1/30/2013 1:31 519.6 519.6 519.9
1/30/2013 1:41 519.4 519.4 519.7
1/30/2013 1:51 519.1 519.1 519.5
1/30/2013 2:01 518.9 518.9 519.2
1/30/2013 2:11 518.7 518.7 519.0
1/30/2013 2:21 518.5 518.5 518.8
1/30/2013 2:31 518.2 518.2 518.5
1/30/2013 2:41 518.0 518.0 518.3
1/30/2013 2:51 517.7 517.7 518.0
1/30/2013 3:01 517.5 517.5 517.8
Page 7
SWMM Hydrology Results
Outfall 916 - 100-yr
Existing Conditions Proposed Conditions - Scenario 1 Proposed Conditions - Scenario 2
Date/Time Total inflow Total inflow Total inflow
M/d/yyyy cfs cfs cfs
1/30/2013 3:11 517.2 517.2 517.5
1/30/2013 3:21 517.0 517.0 517.3
1/30/2013 3:31 516.7 516.7 517.0
1/30/2013 3:41 516.4 516.4 516.7
1/30/2013 3:51 516.1 516.1 516.4
1/30/2013 4:01 515.9 515.9 516.1
1/30/2013 4:11 515.6 515.6 515.8
1/30/2013 4:21 515.3 515.3 515.5
1/30/2013 4:31 514.9 514.9 515.2
1/30/2013 4:41 514.6 514.6 514.9
1/30/2013 4:51 514.3 514.3 514.6
1/30/2013 5:01 513.9 513.9 514.2
1/30/2013 5:11 513.6 513.6 513.9
1/30/2013 5:21 513.2 513.2 513.5
1/30/2013 5:31 512.8 512.8 513.1
1/30/2013 5:41 512.4 512.4 512.7
1/30/2013 5:51 512.0 512.0 512.3
Page 8
Appendix D
Boxelder Creek HEC-RAS Model Results
HEC-RAS River: Boxelder Creek Reach: Boxelder1 Profile: AB 100yr
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Boxelder1 39786 AB 100yr Asbuilt Proj 6509.00 5002.44 5012.84 5012.86 0.000096 1.87 5385.75 821.28 0.11
Boxelder1 39786 AB 100yr Prop 2024 6509.00 5002.44 5012.84 5012.86 0.000096 1.87 5385.75 821.28 0.11
Boxelder1 39786 AB 100yr PC 2024 BTP 6509.00 5002.44 5012.84 5012.86 0.000096 1.87 5385.75 821.28 0.11
Boxelder1 39211 BN AB 100yr Asbuilt Proj 6646.00 4998.00 5012.82 5012.83 0.000026 1.19 9024.66 1015.15 0.06
Boxelder1 39211 BN AB 100yr Prop 2024 6646.00 4998.00 5012.82 5012.83 0.000026 1.19 9024.66 1015.15 0.06
Boxelder1 39211 BN AB 100yr PC 2024 BTP 6646.00 4998.00 5012.82 5012.83 0.000026 1.19 9024.66 1015.15 0.06
Boxelder1 38737 BM AB 100yr Asbuilt Proj 6646.00 4998.00 5012.82 5012.83 0.000006 0.57 15413.07 1156.43 0.03
Boxelder1 38737 BM AB 100yr Prop 2024 6646.00 4998.00 5012.82 5012.83 0.000006 0.57 15413.07 1156.43 0.03
Boxelder1 38737 BM AB 100yr PC 2024 BTP 6646.00 4998.00 5012.82 5012.83 0.000006 0.57 15413.07 1156.43 0.03
Boxelder1 38300 BL AB 100yr Asbuilt Proj 6646.00 4996.00 5012.82 5012.82 0.000004 0.54 17595.97 1271.53 0.02
Boxelder1 38300 BL AB 100yr Prop 2024 6646.00 4996.00 5012.82 5012.82 0.000004 0.54 17595.97 1271.53 0.02
Boxelder1 38300 BL AB 100yr PC 2024 BTP 6646.00 4996.00 5012.82 5012.82 0.000004 0.54 17595.97 1271.53 0.02
Boxelder1 37794 AB 100yr Asbuilt Proj 6646.00 4995.99 5012.82 5012.82 0.000005 0.62 15472.39 1072.30 0.03
Boxelder1 37794 AB 100yr Prop 2024 6646.00 4995.99 5012.82 5012.82 0.000005 0.62 15472.39 1072.30 0.03
Boxelder1 37794 AB 100yr PC 2024 BTP 6646.00 4995.99 5012.82 5012.82 0.000005 0.62 15472.39 1072.30 0.03
Boxelder1 37271 BK AB 100yr Asbuilt Proj 6646.00 4993.95 5012.82 5012.82 0.000007 0.77 12581.93 1301.37 0.03
Boxelder1 37271 BK AB 100yr Prop 2024 6646.00 4993.95 5012.82 5012.82 0.000007 0.77 12581.93 1301.37 0.03
Boxelder1 37271 BK AB 100yr PC 2024 BTP 6646.00 4993.95 5012.82 5012.82 0.000007 0.77 12581.93 1301.37 0.03
Boxelder1 37227 BJ AB 100yr Asbuilt Proj 6646.00 4990.00 5012.81 5012.82 0.000009 0.86 11934.94 1283.29 0.03
Boxelder1 37227 BJ AB 100yr Prop 2024 6646.00 4990.00 5012.81 5012.82 0.000009 0.86 11934.94 1283.29 0.03
Boxelder1 37227 BJ AB 100yr PC 2024 BTP 6646.00 4990.00 5012.81 5012.82 0.000009 0.86 11934.94 1283.29 0.03
Boxelder1 36879 BI AB 100yr Asbuilt Proj 6646.00 4990.00 5012.81 5012.82 0.000010 1.00 10546.21 1216.13 0.04
Boxelder1 36879 BI AB 100yr Prop 2024 6646.00 4990.00 5012.81 5012.82 0.000010 1.00 10546.21 1216.13 0.04
Boxelder1 36879 BI AB 100yr PC 2024 BTP 6646.00 4990.00 5012.81 5012.82 0.000010 1.00 10546.21 1216.13 0.04
Boxelder1 36491 AB 100yr Asbuilt Proj 6646.00 4988.00 5012.81 5012.81 0.000006 0.82 13639.79 1507.30 0.03
Boxelder1 36491 AB 100yr Prop 2024 6646.00 4988.00 5012.81 5012.81 0.000006 0.82 13639.79 1507.30 0.03
Boxelder1 36491 AB 100yr PC 2024 BTP 6646.00 4988.00 5012.81 5012.81 0.000006 0.82 13639.79 1507.30 0.03
Boxelder1 36303 BH AB 100yr Asbuilt Proj 6646.00 4988.00 5012.81 5012.81 0.000005 0.72 15403.60 1708.97 0.03
Boxelder1 36303 BH AB 100yr Prop 2024 6646.00 4988.00 5012.81 5012.81 0.000005 0.72 15403.60 1708.97 0.03
Boxelder1 36303 BH AB 100yr PC 2024 BTP 6646.00 4988.00 5012.81 5012.81 0.000005 0.72 15403.60 1708.97 0.03
Boxelder1 36166 AB 100yr Asbuilt Proj 2622.00 4987.69 5012.81 5012.81 0.000001 0.27 16769.02 1508.38 0.01
Boxelder1 36166 AB 100yr Prop 2024 2622.00 4987.69 5012.81 5012.81 0.000001 0.27 16769.02 1508.38 0.01
Boxelder1 36166 AB 100yr PC 2024 BTP 2622.00 4987.69 5012.81 5012.81 0.000001 0.27 16769.02 1508.38 0.01
Boxelder1 35765 Culvert
Boxelder1 35676 AB 100yr Asbuilt Proj 2622.00 4978.00 4990.84 4983.60 4991.37 0.000628 5.83 449.45 512.68 0.29
Boxelder1 35676 AB 100yr Prop 2024 2622.00 4978.00 4990.84 4983.60 4991.37 0.000628 5.83 449.45 512.68 0.29
Boxelder1 35676 AB 100yr PC 2024 BTP 2622.00 4978.00 4990.84 4983.60 4991.37 0.000628 5.83 449.45 512.68 0.29
Boxelder1 35500 BE AB 100yr Asbuilt Proj 2622.00 4984.79 4990.80 4991.04 0.003432 5.84 855.36 530.56 0.53
Boxelder1 35500 BE AB 100yr Prop 2024 2622.00 4984.79 4990.80 4991.04 0.003432 5.84 855.36 530.56 0.53
Boxelder1 35500 BE AB 100yr PC 2024 BTP 2622.00 4984.79 4990.80 4991.04 0.003432 5.84 855.36 530.56 0.53
Boxelder1 35252 AB 100yr Asbuilt Proj 2622.00 4984.05 4990.22 4990.41 0.002268 4.97 941.57 483.19 0.44
Boxelder1 35252 AB 100yr Prop 2024 2622.00 4984.05 4990.22 4990.41 0.002268 4.97 941.57 483.19 0.44
Boxelder1 35252 AB 100yr PC 2024 BTP 2622.00 4984.05 4990.22 4990.41 0.002268 4.97 941.57 483.19 0.44
Boxelder1 35000 AB 100yr Asbuilt Proj 2622.00 4983.80 4989.88 4989.97 0.001189 3.69 1183.57 489.12 0.32
Boxelder1 35000 AB 100yr Prop 2024 2622.00 4983.80 4989.88 4989.97 0.001189 3.69 1183.57 489.12 0.32
Boxelder1 35000 AB 100yr PC 2024 BTP 2622.00 4983.80 4989.88 4989.97 0.001189 3.69 1183.57 489.12 0.32
Boxelder1 34753 AB 100yr Asbuilt Proj 2622.00 4982.09 4989.67 4989.75 0.000852 3.31 1235.78 428.46 0.27
Boxelder1 34753 AB 100yr Prop 2024 2622.00 4982.09 4989.67 4989.75 0.000852 3.31 1235.78 428.46 0.27
Boxelder1 34753 AB 100yr PC 2024 BTP 2622.00 4982.09 4989.67 4989.75 0.000852 3.31 1235.78 428.46 0.27
Boxelder1 34400 AB 100yr Asbuilt Proj 2622.00 4981.40 4989.08 4989.32 0.002025 5.65 912.34 418.78 0.43
Boxelder1 34400 AB 100yr Prop 2024 2622.00 4981.40 4989.08 4989.32 0.002025 5.65 912.34 418.78 0.43
Boxelder1 34400 AB 100yr PC 2024 BTP 2622.00 4981.40 4989.08 4989.32 0.002025 5.65 912.34 418.78 0.43
Boxelder1 34112 AB 100yr Asbuilt Proj 2622.00 4980.55 4988.29 4988.63 0.002654 6.18 700.69 308.26 0.49
Boxelder1 34112 AB 100yr Prop 2024 2622.00 4980.55 4988.29 4988.63 0.002654 6.18 700.69 308.26 0.49
Boxelder1 34112 AB 100yr PC 2024 BTP 2622.00 4980.55 4988.29 4988.63 0.002654 6.18 700.69 308.26 0.49
Boxelder1 33900 BD AB 100yr Asbuilt Proj 2622.00 4979.66 4987.50 4987.98 0.003595 7.21 645.81 336.91 0.56
Boxelder1 33900 BD AB 100yr Prop 2024 2622.00 4979.66 4987.50 4987.98 0.003595 7.21 645.81 336.91 0.56
Boxelder1 33900 BD AB 100yr PC 2024 BTP 2622.00 4979.66 4987.50 4987.98 0.003595 7.21 645.81 336.91 0.56
Boxelder1 33720 AB 100yr Asbuilt Proj 2622.00 4979.46 4986.98 4987.33 0.003028 6.15 712.07 336.66 0.51
Boxelder1 33720 AB 100yr Prop 2024 2622.00 4979.46 4986.98 4987.33 0.003028 6.15 712.07 336.66 0.51
Boxelder1 33720 AB 100yr PC 2024 BTP 2622.00 4979.46 4986.98 4987.33 0.003028 6.15 712.07 336.66 0.51
Boxelder1 33400 BC AB 100yr Asbuilt Proj 2622.00 4979.31 4985.37 4985.24 4986.01 0.007226 8.54 557.40 360.40 0.78
Boxelder1 33400 BC AB 100yr Prop 2024 2622.00 4979.31 4985.37 4985.24 4986.01 0.007226 8.54 557.40 360.40 0.78
Boxelder1 33400 BC AB 100yr PC 2024 BTP 2622.00 4979.31 4985.37 4985.24 4986.01 0.007226 8.54 557.40 360.40 0.78
Boxelder1 33198 AB 100yr Asbuilt Proj 2622.00 4978.75 4983.19 4983.19 4983.89 0.017207 9.49 433.88 321.32 1.09
Boxelder1 33198 AB 100yr Prop 2024 2622.00 4978.75 4983.19 4983.19 4983.89 0.017207 9.49 433.88 321.32 1.09
Boxelder1 33198 AB 100yr PC 2024 BTP 2622.00 4978.75 4983.19 4983.19 4983.89 0.017207 9.49 433.88 321.32 1.09
HEC-RAS River: Boxelder Creek Reach: Boxelder1 Profile: AB 100yr (Continued)
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Boxelder1 32894 AB 100yr Asbuilt Proj 2622.00 4978.09 4981.88 4982.00 0.001413 2.68 960.71 375.65 0.30
Boxelder1 32894 AB 100yr Prop 2024 2622.00 4978.09 4981.88 4982.00 0.001413 2.68 960.71 375.65 0.30
Boxelder1 32894 AB 100yr PC 2024 BTP 2622.00 4978.09 4981.88 4982.00 0.001413 2.68 960.71 375.65 0.30
Boxelder1 32700 BB AB 100yr Asbuilt Proj 2622.00 4977.96 4981.87 4981.95 0.001034 2.34 1120.93 369.64 0.27
Boxelder1 32700 BB AB 100yr Prop 2024 2622.00 4977.96 4981.87 4981.95 0.001034 2.34 1120.93 369.64 0.27
Boxelder1 32700 BB AB 100yr PC 2024 BTP 2622.00 4977.96 4981.87 4981.95 0.001034 2.34 1120.93 369.64 0.27
Boxelder1 32478 AB 100yr Asbuilt Proj 2622.00 4975.80 4981.51 4981.69 0.002135 4.20 790.74 304.16 0.41
Boxelder1 32478 AB 100yr Prop 2024 2622.00 4975.80 4981.51 4981.69 0.002135 4.20 790.74 304.16 0.41
Boxelder1 32478 AB 100yr PC 2024 BTP 2622.00 4975.80 4981.51 4981.69 0.002135 4.20 790.74 304.16 0.41
Boxelder1 32200 AB 100yr Asbuilt Proj 2622.00 4973.89 4980.92 4981.12 0.002135 5.12 893.07 436.90 0.43
Boxelder1 32200 AB 100yr Prop 2024 2622.00 4973.89 4980.92 4981.12 0.002134 5.12 893.28 436.92 0.43
Boxelder1 32200 AB 100yr PC 2024 BTP 2622.00 4973.89 4980.92 4981.12 0.002135 5.12 893.07 436.90 0.43
Boxelder1 31934 AB 100yr Asbuilt Proj 2622.00 4972.99 4980.31 4980.55 0.002367 5.70 846.90 413.35 0.46
Boxelder1 31934 AB 100yr Prop 2024 2622.00 4972.99 4980.31 4980.55 0.002362 5.69 847.67 413.45 0.45
Boxelder1 31934 AB 100yr PC 2024 BTP 2622.00 4972.99 4980.31 4980.55 0.002367 5.70 846.90 413.35 0.46
Boxelder1 31700 BA AB 100yr Asbuilt Proj 2622.00 4972.34 4979.86 4980.08 0.001848 5.08 914.66 479.56 0.41
Boxelder1 31700 BA AB 100yr Prop 2024 2622.00 4972.34 4979.87 4980.08 0.001837 5.07 916.92 479.94 0.41
Boxelder1 31700 BA AB 100yr PC 2024 BTP 2622.00 4972.34 4979.86 4980.08 0.001848 5.08 914.66 479.56 0.41
Boxelder1 31224 AB 100yr Asbuilt Proj 2622.00 4971.03 4978.57 4978.23 4978.89 0.003065 6.73 824.93 562.89 0.51
Boxelder1 31224 AB 100yr Prop 2024 2638.00 4971.03 4978.57 4978.24 4978.90 0.003070 6.74 828.69 563.73 0.51
Boxelder1 31224 AB 100yr PC 2024 BTP 2622.00 4971.03 4978.57 4978.23 4978.89 0.003065 6.73 824.93 562.89 0.51
Boxelder1 31117 AZ AB 100yr Asbuilt Proj 2622.00 4976.44 4977.69 4977.69 4978.23 0.017688 6.44 447.54 424.93 1.03
Boxelder1 31117 AZ AB 100yr Prop 2024 2638.00 4976.44 4977.69 4977.69 4978.23 0.017660 6.45 449.61 425.49 1.03
Boxelder1 31117 AZ AB 100yr PC 2024 BTP 2622.00 4976.44 4977.69 4977.69 4978.23 0.017688 6.44 447.54 424.93 1.03
HEC-RAS Profile: AB 100yr
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Reach 1 31043 AY AB 100yr AB Project 2511.00 4975.72 4976.84 4976.46 4976.93 0.003728 2.42 1036.96 1148.35 0.45
Reach 1 31043 AY AB 100yr PC 2024 2527.00 4975.72 4976.84 4976.47 4976.94 0.003695 2.42 1043.69 1148.52 0.45
Reach 1 31043 AY AB 100yr PC_BTP 2511.00 4975.72 4976.84 4976.46 4976.93 0.003728 2.42 1036.96 1148.35 0.45
Reach 1 30000 AB 100yr AB Project 2511.00 4967.69 4974.63 4972.61 4974.87 0.001856 6.00 935.97 450.46 0.43
Reach 1 30000 AB 100yr PC 2024 2527.00 4967.69 4974.64 4972.61 4974.88 0.001867 6.02 938.39 450.62 0.43
Reach 1 30000 AB 100yr PC_BTP 2511.00 4967.69 4974.63 4972.61 4974.87 0.001856 6.00 935.97 450.46 0.43
Reach 1 29781 AB 100yr AB Project 2511.00 4967.09 4973.53 4972.62 4974.28 0.004234 8.49 642.99 486.31 0.64
Reach 1 29781 AB 100yr PC 2024 2527.00 4967.09 4973.54 4972.73 4974.29 0.004212 8.48 648.69 486.47 0.64
Reach 1 29781 AB 100yr PC_BTP 2511.00 4967.09 4973.53 4972.62 4974.28 0.004234 8.49 642.99 486.31 0.64
Reach 1 29609 AX AB 100yr AB Project 2511.00 4966.26 4973.29 4972.41 4973.67 0.002503 6.29 832.04 518.66 0.49
Reach 1 29609 AX AB 100yr PC 2024 2527.00 4966.26 4973.31 4972.38 4973.68 0.002481 6.27 839.90 520.32 0.48
Reach 1 29609 AX AB 100yr PC_BTP 2511.00 4966.26 4973.29 4972.41 4973.67 0.002503 6.29 832.04 518.66 0.49
Reach 1 29351 AW AB 100yr AB Project 2511.00 4965.82 4972.81 4971.64 4973.17 0.002342 5.37 747.30 497.12 0.46
Reach 1 29351 AW AB 100yr PC 2024 2527.00 4965.82 4972.84 4971.65 4973.19 0.002304 5.34 759.22 498.26 0.45
Reach 1 29351 AW AB 100yr PC_BTP 2511.00 4965.82 4972.81 4971.64 4973.17 0.002342 5.37 747.30 497.12 0.46
Reach 1 28984 AB 100yr AB Project 2511.00 4965.08 4972.23 4970.56 4972.51 0.001493 4.86 809.59 348.46 0.38
Reach 1 28984 AB 100yr PC 2024 2527.00 4965.08 4972.27 4970.58 4972.54 0.001462 4.83 822.23 351.58 0.37
Reach 1 28984 AB 100yr PC_BTP 2511.00 4965.08 4972.23 4970.56 4972.51 0.001493 4.86 809.59 348.46 0.38
Reach 1 28856 AV AB 100yr AB Project 2511.00 4964.88 4971.96 4970.16 4972.29 0.002079 6.03 788.43 335.32 0.45
Reach 1 28856 AV AB 100yr PC 2024 2527.00 4964.88 4972.01 4970.16 4972.33 0.002005 5.96 804.87 338.22 0.44
Reach 1 28856 AV AB 100yr PC_BTP 2511.00 4964.88 4971.96 4970.16 4972.29 0.002079 6.03 788.43 335.32 0.45
Reach 1 28691 AB 100yr AB Project 2511.00 4964.58 4971.94 4968.61 4972.04 0.000557 3.46 1303.68 499.18 0.24
Reach 1 28691 AB 100yr PC 2024 2527.00 4964.58 4971.98 4968.60 4972.09 0.000540 3.42 1328.57 500.47 0.24
Reach 1 28691 AB 100yr PC_BTP 2511.00 4964.58 4971.94 4968.61 4972.04 0.000557 3.46 1303.68 499.18 0.24
Reach 1 28577 AB 100yr AB Project 2511.00 4963.92 4971.90 4968.36 4971.97 0.000395 2.78 1636.82 602.15 0.20
Reach 1 28577 AB 100yr PC 2024 2527.00 4963.92 4971.95 4968.36 4972.02 0.000386 2.76 1667.62 613.52 0.20
Reach 1 28577 AB 100yr PC_BTP 2511.00 4963.92 4971.90 4968.36 4971.97 0.000395 2.78 1636.82 602.15 0.20
Reach 1 28436 AU AB 100yr AB Project 2511.00 4963.11 4971.85 4969.61 4971.90 0.000508 3.13 1886.34 772.37 0.21
Reach 1 28436 AU AB 100yr PC 2024 2527.00 4963.11 4971.90 4969.60 4971.95 0.000483 3.07 1927.48 773.94 0.21
Reach 1 28436 AU AB 100yr PC_BTP 2511.00 4963.11 4971.85 4969.61 4971.90 0.000508 3.13 1886.34 772.37 0.21
Reach 1 28405 Culvert
Reach 1 28373 AT AB 100yr AB Project 2511.00 4960.95 4969.71 4967.65 4969.91 0.000980 4.96 1095.66 707.27 0.32
Reach 1 28373 AT AB 100yr PC 2024 2527.00 4960.95 4969.73 4967.60 4969.93 0.000982 4.97 1108.14 711.88 0.32
Reach 1 28373 AT AB 100yr PC_BTP 2511.00 4960.95 4969.71 4967.65 4969.91 0.000980 4.96 1095.66 707.27 0.32
Reach 1 28147 AB 100yr AB Project 2511.00 4960.91 4969.20 4967.50 4969.63 0.002506 7.38 687.06 469.42 0.50
Reach 1 28147 AB 100yr PC 2024 2527.00 4960.91 4969.22 4967.50 4969.64 0.002502 7.39 696.27 498.11 0.50
Reach 1 28147 AB 100yr PC_BTP 2511.00 4960.91 4969.20 4967.50 4969.63 0.002506 7.38 687.06 469.42 0.50
Reach 1 27734 AB 100yr AB Project 2511.00 4959.46 4968.63 4966.22 4969.03 0.001497 5.39 557.16 134.39 0.39
Reach 1 27734 AB 100yr PC 2024 2527.00 4959.46 4968.65 4966.24 4969.05 0.001499 5.40 559.66 134.64 0.39
Reach 1 27734 AB 100yr PC_BTP 2511.00 4959.46 4968.63 4966.22 4969.03 0.001497 5.39 557.16 134.39 0.39
Reach 1 27304 AS AB 100yr AB Project 2511.00 4957.83 4967.34 4966.09 4968.06 0.003074 7.37 464.22 162.00 0.54
Reach 1 27304 AS AB 100yr PC 2024 2527.00 4957.83 4967.38 4966.01 4968.10 0.003009 7.33 471.21 163.44 0.53
Reach 1 27304 AS AB 100yr PC_BTP 2511.00 4957.83 4967.34 4966.09 4968.06 0.003074 7.37 464.22 162.00 0.54
Reach 1 27277 Culvert
Reach 1 27250 AB 100yr AB Project 2511.00 4958.01 4965.90 4965.90 4967.12 0.006689 11.09 390.00 139.51 0.78
Reach 1 27250 AB 100yr PC 2024 2527.00 4958.01 4965.90 4965.90 4967.13 0.006745 11.14 390.68 139.56 0.78
Reach 1 27250 AB 100yr PC_BTP 2511.00 4958.01 4965.90 4965.90 4967.12 0.006689 11.09 390.00 139.51 0.78
Reach 1 27006 AB 100yr AB Project 2511.00 4957.23 4964.96 4964.41 4965.62 0.003716 8.06 542.33 218.91 0.59
Reach 1 27006 AB 100yr PC 2024 2527.00 4957.23 4964.97 4964.39 4965.64 0.003706 8.06 545.86 219.34 0.59
Reach 1 27006 AB 100yr PC_BTP 2511.00 4957.23 4964.96 4964.41 4965.62 0.003716 8.06 542.33 218.91 0.59
Reach 1 26814 AB 100yr AB Project 2511.00 4956.46 4964.84 4963.66 4965.13 0.001843 5.91 802.59 288.11 0.41
Reach 1 26814 AB 100yr PC 2024 2527.00 4956.46 4964.86 4963.73 4965.15 0.001837 5.91 807.66 288.72 0.41
Reach 1 26814 AB 100yr PC_BTP 2511.00 4956.46 4964.84 4963.66 4965.13 0.001843 5.91 802.59 288.11 0.41
Reach 1 26430 AR AB 100yr AB Project 2511.00 4955.93 4964.28 4962.80 4964.62 0.001635 5.99 720.92 208.32 0.40
Reach 1 26430 AR AB 100yr PC 2024 2527.00 4955.93 4964.30 4962.81 4964.63 0.001632 6.00 724.89 208.57 0.40
Reach 1 26430 AR AB 100yr PC_BTP 2511.00 4955.93 4964.28 4962.80 4964.62 0.001635 5.99 720.92 208.32 0.40
Reach 1 25898 AB 100yr AB Project 2511.00 4953.49 4963.20 4961.59 4963.78 0.002086 6.90 524.97 141.62 0.45
Reach 1 25898 AB 100yr PC 2024 2527.00 4953.49 4963.22 4961.60 4963.80 0.002085 6.91 527.87 141.86 0.45
Reach 1 25898 AB 100yr PC_BTP 2511.00 4953.49 4963.20 4961.59 4963.78 0.002086 6.90 524.97 141.62 0.45
Reach 1 25605 AQ AB 100yr AB Project 2511.00 4949.98 4962.67 4961.13 4963.15 0.002119 7.22 711.48 284.66 0.42
Reach 1 25605 AQ AB 100yr PC 2024 2527.00 4949.98 4962.70 4961.15 4963.18 0.002084 7.18 720.66 285.27 0.42
Reach 1 25605 AQ AB 100yr PC_BTP 2511.00 4949.98 4962.67 4961.13 4963.15 0.002119 7.22 711.48 284.66 0.42
Reach 1 25366 AB 100yr AB Project 2511.00 4949.67 4960.07 4960.07 4962.14 0.008458 12.38 283.02 135.46 0.82
Reach 1 25366 AB 100yr PC 2024 2527.00 4949.67 4960.07 4960.07 4962.17 0.008566 12.46 283.02 135.46 0.83
Reach 1 25366 AB 100yr PC_BTP 2511.00 4949.67 4960.07 4960.07 4962.14 0.008458 12.38 283.02 135.46 0.82
HEC-RAS Profile: AB 100yr (Continued)
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Reach 1 24907 AP AB 100yr AB Project 2511.00 4947.15 4959.06 4955.74 4959.77 0.001730 7.38 491.53 152.35 0.42
Reach 1 24907 AP AB 100yr PC 2024 2527.00 4947.15 4959.08 4955.74 4959.79 0.001740 7.41 493.54 152.51 0.42
Reach 1 24907 AP AB 100yr PC_BTP 2511.00 4947.15 4959.06 4955.74 4959.77 0.001730 7.38 491.53 152.35 0.42
Reach 1 24703 AB 100yr AB Project 2511.00 4946.72 4958.12 4958.12 4959.18 0.005185 9.37 429.48 189.83 0.62
Reach 1 24703 AB 100yr PC 2024 2527.00 4946.72 4958.13 4958.13 4959.20 0.005223 9.41 430.59 189.87 0.63
Reach 1 24703 AB 100yr PC_BTP 2511.00 4946.72 4958.12 4958.12 4959.18 0.005185 9.37 429.48 189.83 0.62
Reach 1 24412 AO AB 100yr AB Project 2511.00 4946.08 4952.60 4950.00 4952.66 0.000411 2.67 1794.41 928.44 0.20
Reach 1 24412 AO AB 100yr PC 2024 2527.00 4946.08 4952.62 4950.01 4952.68 0.000405 2.65 1813.35 931.57 0.20
Reach 1 24412 AO AB 100yr PC_BTP 2511.00 4946.08 4952.60 4950.00 4952.66 0.000411 2.67 1794.41 928.44 0.20
Reach 1 23987 AN AB 100yr AB Project 2511.00 4943.96 4952.58 4947.69 4952.60 0.000064 1.28 3299.14 992.09 0.08
Reach 1 23987 AN AB 100yr PC 2024 2527.00 4943.96 4952.61 4947.73 4952.62 0.000064 1.28 3318.17 995.30 0.08
Reach 1 23987 AN AB 100yr PC_BTP 2511.00 4943.96 4952.58 4947.69 4952.60 0.000064 1.28 3299.14 992.09 0.08
Reach 1 23647 AB 100yr AB Project 2511.00 4941.78 4952.56 4946.60 4952.58 0.000054 1.25 3038.95 894.41 0.08
Reach 1 23647 AB 100yr PC 2024 2527.00 4941.78 4952.59 4946.61 4952.60 0.000054 1.25 3053.41 907.88 0.08
Reach 1 23647 AB 100yr PC_BTP 2511.00 4941.78 4952.56 4946.60 4952.58 0.000054 1.25 3038.95 894.41 0.08
Reach 1 23235 AM AB 100yr AB Project 2615.00 4942.17 4952.49 4946.91 4952.54 0.000133 2.18 1651.03 1046.64 0.13
Reach 1 23235 AM AB 100yr PC 2024 2631.00 4942.17 4952.51 4946.93 4952.56 0.000134 2.19 1656.39 1047.53 0.13
Reach 1 23235 AM AB 100yr PC_BTP 2615.00 4942.17 4952.49 4946.91 4952.54 0.000133 2.18 1651.03 1046.64 0.13
Reach 1 23040 AB 100yr AB Project 2615.00 4941.57 4949.22 4949.22 4951.73 0.009904 15.30 248.96 51.03 1.02
Reach 1 23040 AB 100yr PC 2024 2631.00 4941.57 4949.27 4949.27 4951.76 0.009727 15.24 251.75 51.25 1.01
Reach 1 23040 AB 100yr PC_BTP 2615.00 4941.57 4949.22 4949.22 4951.73 0.009904 15.30 248.96 51.03 1.02
Reach 1 22783 AB 100yr AB Project 2615.00 4941.21 4946.40 4944.40 4946.62 0.002635 6.13 770.96 264.84 0.49
Reach 1 22783 AB 100yr PC 2024 2631.00 4941.21 4946.42 4944.41 4946.63 0.002633 6.14 774.08 264.96 0.49
Reach 1 22783 AB 100yr PC_BTP 2615.00 4941.21 4946.40 4944.40 4946.62 0.002635 6.13 770.96 264.84 0.49
Reach 1 22462 AB 100yr AB Project 2615.00 4939.16 4945.33 4943.58 4945.72 0.004265 7.97 582.42 144.46 0.61
Reach 1 22462 AB 100yr PC 2024 2631.00 4939.16 4945.34 4943.59 4945.74 0.004270 7.99 584.53 144.57 0.61
Reach 1 22462 AB 100yr PC_BTP 2615.00 4939.16 4945.33 4943.58 4945.72 0.004265 7.97 582.42 144.46 0.61
Reach 1 22122 AL AB 100yr AB Project 2615.00 4938.99 4944.76 4942.76 4944.95 0.002588 6.26 838.63 231.75 0.49
Reach 1 22122 AL AB 100yr PC 2024 2631.00 4938.99 4944.78 4942.76 4944.97 0.002583 6.27 842.36 231.84 0.49
Reach 1 22122 AL AB 100yr PC_BTP 2615.00 4938.99 4944.76 4942.76 4944.95 0.002588 6.26 838.63 231.75 0.49
Reach 1 21721 AB 100yr AB Project 2615.00 4938.07 4943.82 4942.06 4944.15 0.003486 7.47 656.61 167.40 0.58
Reach 1 21721 AB 100yr PC 2024 2631.00 4938.07 4943.83 4942.08 4944.17 0.003483 7.49 659.39 167.49 0.58
Reach 1 21721 AB 100yr PC_BTP 2615.00 4938.07 4943.82 4942.06 4944.15 0.003486 7.47 656.61 167.40 0.58
Reach 1 21273 AK AB 100yr AB Project 2615.00 4936.63 4942.97 4940.62 4943.19 0.002306 6.48 773.25 176.74 0.47
Reach 1 21273 AK AB 100yr PC 2024 2631.00 4936.63 4942.99 4940.63 4943.21 0.002308 6.50 776.18 176.90 0.47
Reach 1 21273 AK AB 100yr PC_BTP 2615.00 4936.63 4942.97 4940.62 4943.19 0.002306 6.48 773.25 176.74 0.47
Reach 1 21034 AB 100yr AB Project 2615.00 4936.41 4941.69 4940.69 4942.42 0.006367 9.64 477.43 136.23 0.77
Reach 1 21034 AB 100yr PC 2024 2631.00 4936.41 4941.70 4940.70 4942.44 0.006366 9.66 479.42 136.32 0.77
Reach 1 21034 AB 100yr PC_BTP 2615.00 4936.41 4941.69 4940.69 4942.42 0.006367 9.64 477.43 136.23 0.77
Reach 1 20753 AJ AB 100yr AB Project 2615.00 4935.27 4940.58 4938.97 4940.89 0.005025 7.91 624.60 179.21 0.65
Reach 1 20753 AJ AB 100yr PC 2024 2631.00 4935.27 4940.59 4938.97 4940.91 0.005002 7.91 628.02 179.38 0.65
Reach 1 20753 AJ AB 100yr PC_BTP 2615.00 4935.27 4940.58 4938.97 4940.89 0.005025 7.91 624.60 179.21 0.65
Reach 1 20518 AB 100yr AB Project 2615.00 4934.92 4939.90 4938.00 4940.11 0.003064 5.90 798.17 349.11 0.52
Reach 1 20518 AB 100yr PC 2024 2631.00 4934.92 4939.92 4938.00 4940.13 0.003021 5.89 804.89 349.45 0.51
Reach 1 20518 AB 100yr PC_BTP 2615.00 4934.92 4939.90 4938.00 4940.11 0.003064 5.90 798.17 349.11 0.52
Reach 1 20262 AB 100yr AB Project 2780.00 4934.41 4939.77 4937.23 4939.89 0.000771 3.24 1006.54 410.51 0.27
Reach 1 20262 AB 100yr PC 2024 2796.00 4934.41 4939.80 4937.22 4939.92 0.000760 3.23 1015.31 411.23 0.26
Reach 1 20262 AB 100yr PC_BTP 2780.00 4934.41 4939.77 4937.23 4939.89 0.000771 3.24 1006.54 410.51 0.27
Reach 1 19830 AB 100yr AB Project 2780.00 4933.87 4939.46 4937.08 4939.62 0.001815 5.01 1143.76 550.69 0.41
Reach 1 19830 AB 100yr PC 2024 2796.00 4933.87 4939.50 4937.09 4939.65 0.001764 4.97 1161.35 552.65 0.40
Reach 1 19830 AB 100yr PC_BTP 2780.00 4933.87 4939.46 4937.08 4939.62 0.001815 5.01 1143.76 550.69 0.41
Reach 1 19613 AI AB 100yr AB Project 2780.00 4931.25 4939.08 4937.99 4939.23 0.003224 5.27 1152.29 620.64 0.47
Reach 1 19613 AI AB 100yr PC 2024 2796.00 4931.25 4939.14 4937.98 4939.28 0.002977 5.12 1190.62 625.82 0.45
Reach 1 19613 AI AB 100yr PC_BTP 2780.00 4931.25 4939.08 4937.99 4939.23 0.003224 5.27 1152.29 620.64 0.47
Reach 1 19603 Culvert
Reach 1 19593 AB 100yr AB Project 2780.00 4931.22 4939.08 4938.11 4939.23 0.002895 5.36 1220.72 635.41 0.47
Reach 1 19593 AB 100yr PC 2024 2796.00 4931.22 4939.10 4938.11 4939.24 0.002857 5.34 1230.65 635.73 0.46
Reach 1 19593 AB 100yr PC_BTP 2780.00 4931.22 4939.08 4938.11 4939.23 0.002895 5.36 1220.72 635.41 0.47
Reach 1 19233 AB 100yr AB Project 2780.00 4930.62 4938.72 4936.04 4938.87 0.000971 4.74 1324.07 421.91 0.32
Reach 1 19233 AB 100yr PC 2024 2796.00 4930.62 4938.73 4936.04 4938.88 0.000968 4.74 1331.29 423.00 0.32
Reach 1 19233 AB 100yr PC_BTP 2780.00 4930.62 4938.72 4936.04 4938.87 0.000971 4.74 1324.07 421.91 0.32
Reach 1 18944 AB 100yr AB Project 2780.00 4929.24 4937.03 4936.13 4938.07 0.005161 10.83 444.98 133.36 0.72
Reach 1 18944 AB 100yr PC 2024 2796.00 4929.24 4937.05 4936.12 4938.09 0.005166 10.85 446.80 133.45 0.72
Reach 1 18944 AB 100yr PC_BTP 2780.00 4929.24 4937.03 4936.13 4938.07 0.005161 10.83 444.98 133.36 0.72
HEC-RAS Profile: AB 100yr (Continued)
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Reach 1 18539 AH AB 100yr AB Project 2780.00 4928.66 4935.07 4934.45 4935.79 0.006442 10.00 481.20 154.33 0.76
Reach 1 18539 AH AB 100yr PC 2024 2796.00 4928.66 4935.08 4934.46 4935.81 0.006448 10.02 483.01 154.48 0.76
Reach 1 18539 AH AB 100yr PC_BTP 2780.00 4928.66 4935.07 4934.45 4935.79 0.006442 10.00 481.20 154.33 0.76
Reach 1 18128 AG AB 100yr AB Project 2780.00 4927.64 4934.20 4932.34 4934.46 0.002194 6.10 837.53 245.56 0.46
Reach 1 18128 AG AB 100yr PC 2024 2796.00 4927.64 4934.21 4932.35 4934.47 0.002199 6.11 840.17 245.71 0.46
Reach 1 18128 AG AB 100yr PC_BTP 2780.00 4927.64 4934.20 4932.34 4934.46 0.002194 6.10 837.53 245.56 0.46
Reach 1 17756 AF AB 100yr AB Project 2780.00 4926.00 4932.08 4931.74 4933.04 0.007917 11.16 437.60 281.13 0.86
Reach 1 17756 AF AB 100yr PC 2024 2796.00 4926.00 4932.11 4931.75 4933.07 0.007758 11.10 442.11 281.64 0.85
Reach 1 17756 AF AB 100yr PC_BTP 2780.00 4926.00 4932.08 4931.74 4933.04 0.007917 11.16 437.60 281.13 0.86
Reach 1 17661 Culvert
Reach 1 17566 AB 100yr AB Project 2780.00 4924.44 4930.90 4930.90 4932.44 0.008576 12.22 361.01 247.49 0.90
Reach 1 17566 AB 100yr PC 2024 2796.00 4924.44 4930.95 4930.95 4932.46 0.008280 12.09 366.95 252.12 0.89
Reach 1 17566 AB 100yr PC_BTP 2780.00 4924.44 4930.90 4930.90 4932.44 0.008576 12.22 361.01 247.49 0.90
Reach 2 17159 AB 100yr AB Project 2780.00 4923.19 4930.35 4928.70 4930.53 0.001644 5.58 934.86 279.27 0.39
Reach 2 17159 AB 100yr PC 2024 2796.00 4923.19 4930.36 4928.69 4930.55 0.001642 5.58 938.96 280.08 0.39
Reach 2 17159 AB 100yr PC_BTP 2780.00 4923.19 4930.35 4928.70 4930.53 0.001644 5.58 934.86 279.27 0.39
Reach 2 16631 AE AB 100yr AB Project 2780.00 4921.99 4929.63 4927.78 4929.85 0.001706 5.86 894.25 259.11 0.40
Reach 2 16631 AE AB 100yr PC 2024 2796.00 4921.99 4929.65 4927.78 4929.87 0.001703 5.87 898.43 259.41 0.40
Reach 2 16631 AE AB 100yr PC_BTP 2780.00 4921.99 4929.63 4927.78 4929.85 0.001706 5.86 894.25 259.11 0.40
Reach 2 16525 AB 100yr AB Project 2780.00 4921.58 4929.55 4927.40 4929.74 0.001375 5.26 957.46 255.44 0.35
Reach 2 16525 AB 100yr PC 2024 2796.00 4921.58 4929.57 4927.41 4929.75 0.001376 5.27 961.58 255.94 0.35
Reach 2 16525 AB 100yr PC_BTP 2780.00 4921.58 4929.55 4927.40 4929.74 0.001375 5.26 957.46 255.44 0.35
Reach 2 16020 AB 100yr AB Project 2780.00 4920.71 4928.93 4926.74 4929.16 0.001499 5.88 896.92 237.38 0.38
Reach 2 16020 AB 100yr PC 2024 2796.00 4920.71 4928.95 4926.76 4929.17 0.001498 5.89 900.86 237.69 0.38
Reach 2 16020 AB 100yr PC_BTP 2780.00 4920.71 4928.93 4926.74 4929.16 0.001499 5.88 896.92 237.38 0.38
Reach 3 15814 AB 100yr AB Project 2780.00 4920.16 4928.44 4926.34 4928.78 0.002099 6.66 718.05 184.21 0.44
Reach 3 15814 AB 100yr PC 2024 2796.00 4920.16 4928.46 4926.34 4928.80 0.002100 6.67 721.02 184.54 0.44
Reach 3 15814 AB 100yr PC_BTP 2780.00 4920.16 4928.44 4926.34 4928.78 0.002099 6.66 718.05 184.21 0.44
Reach 3 15675 AB 100yr AB Project 2780.00 4920.18 4927.28 4926.84 4928.36 0.006110 11.01 421.38 116.78 0.75
Reach 3 15675 AB 100yr PC 2024 2796.00 4920.18 4927.29 4926.86 4928.37 0.006119 11.03 422.92 116.88 0.75
Reach 3 15675 AB 100yr PC_BTP 2780.00 4920.18 4927.28 4926.84 4928.36 0.006110 11.01 421.38 116.78 0.75
Reach 4 15491 AB 100yr AB Project 2780.00 4919.52 4926.46 4925.67 4927.20 0.005399 9.89 502.70 154.86 0.70
Reach 4 15491 AB 100yr PC 2024 2796.00 4919.52 4926.47 4925.68 4927.22 0.005400 9.90 504.82 155.09 0.70
Reach 4 15491 AB 100yr PC_BTP 2780.00 4919.52 4926.46 4925.67 4927.20 0.005399 9.89 502.70 154.86 0.70
Reach 4 15109 AB 100yr AB Project 2780.00 4919.19 4926.69 4921.66 4926.73 0.000325 2.59 1786.86 378.38 0.17
Reach 4 15109 AB 100yr PC 2024 2796.00 4919.19 4926.70 4921.66 4926.74 0.000325 2.59 1792.22 378.52 0.17
Reach 4 15109 AB 100yr PC_BTP 2780.00 4919.19 4926.69 4921.66 4926.73 0.000325 2.59 1786.86 378.38 0.17
Reach 5 14859 AB 100yr AB Project 2780.00 4919.10 4926.64 4922.60 4926.66 0.000188 1.96 2514.17 632.06 0.13
Reach 5 14859 AB 100yr PC 2024 2796.00 4919.10 4926.65 4922.76 4926.68 0.000188 1.97 2523.13 633.51 0.13
Reach 5 14859 AB 100yr PC_BTP 2780.00 4919.10 4926.64 4922.60 4926.66 0.000188 1.96 2514.17 632.06 0.13
Reach 5 14566 AC AB 100yr AB Project 2780.00 4917.61 4926.52 4923.53 4926.59 0.000414 3.26 1617.97 528.93 0.20
Reach 5 14566 AC AB 100yr PC 2024 2796.00 4917.61 4926.54 4923.53 4926.60 0.000414 3.26 1625.21 529.95 0.20
Reach 5 14566 AC AB 100yr PC_BTP 2780.00 4917.61 4926.52 4923.53 4926.59 0.000414 3.26 1617.97 528.93 0.20
Reach 5 14127 AB AB 100yr AB Project 2780.00 4917.20 4924.94 4924.94 4926.12 0.006853 11.53 436.62 156.83 0.78
Reach 5 14127 AB AB 100yr PC 2024 2796.00 4917.20 4924.95 4924.95 4926.14 0.006877 11.56 438.00 156.89 0.79
Reach 5 14127 AB AB 100yr PC_BTP 2780.00 4917.20 4924.94 4924.94 4926.12 0.006853 11.53 436.62 156.83 0.78
Reach 5 13868 AB 100yr AB Project 2780.00 4917.05 4923.24 4921.27 4923.45 0.001803 5.51 850.40 229.86 0.41
Reach 5 13868 AB 100yr PC 2024 2796.00 4917.05 4923.26 4921.28 4923.47 0.001793 5.51 855.00 229.99 0.41
Reach 5 13868 AB 100yr PC_BTP 2780.00 4917.05 4923.24 4921.27 4923.45 0.001803 5.51 850.40 229.86 0.41
Reach 5 13700 AA AB 100yr AB Project 2780.00 4916.37 4922.95 4921.06 4923.18 0.001832 5.76 814.89 207.89 0.41
Reach 5 13700 AA AB 100yr PC 2024 2796.00 4916.37 4922.97 4921.08 4923.20 0.001825 5.77 819.16 208.08 0.41
Reach 5 13700 AA AB 100yr PC_BTP 2780.00 4916.37 4922.95 4921.06 4923.18 0.001832 5.76 814.89 207.89 0.41
Reach 5 13237 AB 100yr AB Project 2780.00 4915.62 4921.54 4920.29 4922.04 0.004719 8.17 534.15 180.19 0.65
Reach 5 13237 AB 100yr PC 2024 2796.00 4915.62 4921.58 4920.30 4922.07 0.004641 8.14 538.97 180.57 0.65
Reach 5 13237 AB 100yr PC_BTP 2780.00 4915.62 4921.54 4920.29 4922.04 0.004719 8.17 534.15 180.19 0.65
Reach 5 12954 AB 100yr AB Project 2780.00 4915.50 4921.00 4918.75 4921.21 0.001572 4.72 817.20 325.30 0.38
Reach 5 12954 AB 100yr PC 2024 2796.00 4915.50 4921.05 4918.76 4921.25 0.001533 4.70 826.38 327.47 0.38
Reach 5 12954 AB 100yr PC_BTP 2780.00 4915.50 4921.00 4918.75 4921.21 0.001572 4.72 817.20 325.30 0.38
Reach 5 12758 AB 100yr AB Project 2780.00 4914.26 4920.77 4918.23 4920.93 0.001253 4.56 922.75 441.66 0.35
Reach 5 12758 AB 100yr PC 2024 2796.00 4914.26 4920.82 4918.24 4920.98 0.001219 4.52 934.08 443.02 0.34
Reach 5 12758 AB 100yr PC_BTP 2780.00 4914.26 4920.77 4918.23 4920.93 0.001253 4.56 922.75 441.66 0.35
Reach 5 12525 Z AB 100yr AB Project 2780.00 4912.27 4920.68 4917.48 4920.75 0.000430 2.88 1501.17 542.93 0.20
Reach 5 12525 Z AB 100yr PC 2024 2796.00 4912.27 4920.74 4917.47 4920.80 0.000418 2.86 1519.62 543.52 0.20
Reach 5 12525 Z AB 100yr PC_BTP 2780.00 4912.27 4920.68 4917.48 4920.75 0.000430 2.88 1501.17 542.93 0.20
Reach 5 12172 AB 100yr AB Project 2780.00 4911.02 4920.60 4915.81 4920.66 0.000197 2.24 1659.60 684.52 0.15
HEC-RAS Profile: AB 100yr (Continued)
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Reach 5 12172 AB 100yr PC 2024 2796.00 4911.02 4920.66 4915.81 4920.72 0.000193 2.23 1678.48 695.47 0.14
Reach 5 12172 AB 100yr PC_BTP 2780.00 4911.02 4920.60 4915.81 4920.66 0.000197 2.24 1659.60 684.52 0.15
Reach 5 11797 Y AB 100yr AB Project 2788.00 4908.60 4919.87 4913.78 4920.39 0.000785 5.80 480.67 595.82 0.31
Reach 5 11797 Y AB 100yr PC 2024 2805.00 4908.60 4919.93 4913.74 4920.45 0.000781 5.80 483.25 609.38 0.31
Reach 5 11797 Y AB 100yr PC_BTP 2788.00 4908.60 4919.87 4913.78 4920.39 0.000785 5.80 480.67 595.82 0.31
Reach 5 11662 Culvert
Reach 5 11527 X AB 100yr AB Project 2788.00 4910.00 4916.85 4915.31 4918.32 0.004374 9.73 286.51 449.24 0.67
Reach 5 11527 X AB 100yr PC 2024 2805.00 4910.00 4916.86 4915.36 4918.35 0.004389 9.76 287.26 451.04 0.67
Reach 5 11527 X AB 100yr PC_BTP 2788.00 4910.00 4916.85 4915.31 4918.32 0.004374 9.73 286.51 449.24 0.67
Reach 5 11422 W AB 100yr AB Project 3286.00 4909.26 4915.32 4915.32 4917.34 0.014929 11.39 288.38 144.43 0.99
Reach 5 11422 W AB 100yr PC 2024 3313.00 4909.26 4915.36 4915.36 4917.38 0.014773 11.38 291.18 146.84 0.99
Reach 5 11422 W AB 100yr PC_BTP 3286.00 4909.26 4915.32 4915.32 4917.34 0.014929 11.39 288.38 144.43 0.99
Reach 5 11368 AB 100yr AB Project 3286.00 4910.00 4914.34 4912.46 4914.59 0.001952 4.00 821.37 370.72 0.36
Reach 5 11368 AB 100yr PC 2024 3313.00 4910.00 4914.35 4912.48 4914.60 0.001956 4.02 824.94 371.39 0.36
Reach 5 11368 AB 100yr PC_BTP 3286.00 4910.00 4914.34 4912.46 4914.59 0.001952 4.00 821.37 370.72 0.36
Reach 5 10968 V AB 100yr AB Project 3286.00 4909.00 4913.63 4912.40 4913.77 0.002332 4.57 1319.01 518.76 0.40
Reach 5 10968 V AB 100yr PC 2024 3313.00 4909.00 4913.65 4912.42 4913.79 0.002319 4.57 1328.89 519.38 0.40
Reach 5 10968 V AB 100yr PC_BTP 3286.00 4909.00 4913.63 4912.40 4913.77 0.002332 4.57 1319.01 518.76 0.40
Reach 5 10652 AB 100yr AB Project 3286.00 4906.82 4913.34 4911.56 4913.45 0.001431 4.18 1455.69 451.76 0.32
Reach 5 10652 AB 100yr PC 2024 3313.00 4906.82 4913.36 4911.58 4913.47 0.001427 4.19 1464.96 452.21 0.32
Reach 5 10652 AB 100yr PC_BTP 3286.00 4906.82 4913.34 4911.56 4913.45 0.001431 4.18 1455.69 451.76 0.32
Reach 5 10143 U AB 100yr AB Project 3286.00 4907.00 4912.98 4910.65 4913.11 0.001070 3.59 1322.89 336.66 0.28
Reach 5 10143 U AB 100yr PC 2024 3313.00 4907.00 4913.00 4910.65 4913.13 0.001071 3.60 1329.80 336.81 0.28
Reach 5 10143 U AB 100yr PC_BTP 3286.00 4907.00 4912.98 4910.65 4913.11 0.001070 3.59 1322.89 336.66 0.28
Reach 5 9971 AB 100yr AB Project 3286.00 4906.00 4912.07 4910.31 4912.72 0.004172 7.01 584.84 145.25 0.51
Reach 5 9971 AB 100yr PC 2024 3313.00 4906.00 4912.08 4910.31 4912.74 0.004205 7.04 586.68 145.41 0.51
Reach 5 9971 AB 100yr PC_BTP 3286.00 4906.00 4912.07 4910.31 4912.72 0.004172 7.01 584.84 145.25 0.51
Reach 5 9599 AB 100yr AB Project 3376.00 4904.00 4911.22 4910.23 4911.51 0.002452 5.39 1060.76 565.34 0.42
Reach 5 9599 AB 100yr PC 2024 3402.00 4904.00 4911.24 4910.25 4911.52 0.002457 5.41 1067.40 567.71 0.42
Reach 5 9599 AB 100yr PC_BTP 3376.00 4904.00 4911.22 4910.23 4911.51 0.002452 5.39 1060.76 565.34 0.42
Reach 5 9314 AB 100yr AB Project 3376.00 4902.57 4910.95 4909.76 4911.11 0.001672 4.45 1371.69 715.09 0.34
Reach 5 9314 AB 100yr PC 2024 3402.00 4902.57 4910.96 4909.77 4911.12 0.001669 4.45 1381.13 716.60 0.34
Reach 5 9314 AB 100yr PC_BTP 3376.00 4902.57 4910.95 4909.76 4911.11 0.001672 4.45 1371.69 715.09 0.34
Reach 5 8918 AB 100yr AB Project 3376.00 4901.19 4910.40 4909.05 4910.66 0.001916 5.35 1198.19 621.46 0.38
Reach 5 8918 AB 100yr PC 2024 3402.00 4901.19 4910.42 4909.07 4910.68 0.001901 5.34 1209.75 625.68 0.38
Reach 5 8918 AB 100yr PC_BTP 3376.00 4901.19 4910.40 4909.05 4910.66 0.001916 5.35 1198.19 621.46 0.38
Reach 5 8678 T AB 100yr AB Project 3376.00 4901.00 4909.73 4908.69 4910.20 0.002255 6.58 870.34 373.66 0.47
Reach 5 8678 T AB 100yr PC 2024 3402.00 4901.00 4909.74 4908.71 4910.22 0.002252 6.59 877.29 375.22 0.47
Reach 5 8678 T AB 100yr PC_BTP 3376.00 4901.00 4909.73 4908.69 4910.20 0.002255 6.58 870.34 373.66 0.47
Reach 5 8177 AB 100yr AB Project 3376.00 4901.00 4907.94 4907.26 4908.67 0.004608 8.24 626.22 200.31 0.65
Reach 5 8177 AB 100yr PC 2024 3402.00 4901.00 4907.96 4907.29 4908.68 0.004623 8.26 628.96 200.48 0.65
Reach 5 8177 AB 100yr PC_BTP 3376.00 4901.00 4907.94 4907.26 4908.67 0.004608 8.24 626.22 200.31 0.65
Reach 5 7663 S AB 100yr AB Project 3376.00 4898.00 4905.21 4905.21 4906.15 0.006279 9.48 637.68 296.11 0.75
Reach 5 7663 S AB 100yr PC 2024 3402.00 4898.00 4905.22 4905.22 4906.16 0.006278 9.49 641.87 296.40 0.75
Reach 5 7663 S AB 100yr PC_BTP 3376.00 4898.00 4905.21 4905.21 4906.15 0.006279 9.48 637.68 296.11 0.75
Reach 6 7256 R AB 100yr AB Project 951.00 4897.13 4903.69 4902.71 4903.80 0.001404 3.29 491.16 311.96 0.30
Reach 6 7256 R AB 100yr PC 2024 951.00 4897.13 4903.69 4902.71 4903.80 0.001404 3.29 491.16 311.96 0.30
Reach 6 7256 R AB 100yr PC_BTP 951.00 4897.13 4903.69 4902.71 4903.80 0.001404 3.29 491.16 311.96 0.30
Reach 6 7001 AB 100yr AB Project 951.00 4896.35 4902.90 4899.85 4903.30 0.001856 5.09 186.94 217.21 0.36
Reach 6 7001 AB 100yr PC 2024 951.00 4896.35 4902.90 4899.85 4903.30 0.001856 5.09 186.94 217.21 0.36
Reach 6 7001 AB 100yr PC_BTP 951.00 4896.35 4902.90 4899.85 4903.30 0.001856 5.09 186.94 217.21 0.36
Reach 6 6918 Bridge
Reach 6 6852 AB 100yr AB Project 951.00 4895.70 4900.46 4899.08 4901.21 0.004890 6.94 137.01 94.63 0.57
Reach 6 6852 AB 100yr PC 2024 951.00 4895.70 4900.46 4899.08 4901.21 0.004890 6.94 137.01 94.63 0.57
Reach 6 6852 AB 100yr PC_BTP 951.00 4895.70 4900.46 4899.08 4901.21 0.004890 6.94 137.01 94.63 0.57
Reach 6 6506 P AB 100yr AB Project 951.00 4892.50 4898.61 4897.91 4899.08 0.006847 5.57 181.14 108.09 0.62
Reach 6 6506 P AB 100yr PC 2024 951.00 4892.50 4898.61 4897.91 4899.08 0.006847 5.57 181.14 108.09 0.62
Reach 6 6506 P AB 100yr PC_BTP 951.00 4892.50 4898.61 4897.91 4899.08 0.006847 5.57 181.14 108.09 0.62
Reach 6 6391 O AB 100yr AB Project 951.00 4891.34 4898.38 4895.48 4898.58 0.002300 3.62 262.56 62.86 0.31
Reach 6 6391 O AB 100yr PC 2024 951.00 4891.34 4898.38 4895.48 4898.58 0.002300 3.62 262.56 62.86 0.31
Reach 6 6391 O AB 100yr PC_BTP 951.00 4891.34 4898.38 4895.48 4898.58 0.002300 3.62 262.56 62.86 0.31
Reach 6 6243 N AB 100yr AB Project 951.00 4890.67 4898.13 4895.00 4898.27 0.001670 3.09 310.15 102.72 0.27
Reach 6 6243 N AB 100yr PC 2024 951.00 4890.67 4898.13 4895.00 4898.27 0.001670 3.09 310.15 102.72 0.27
Reach 6 6243 N AB 100yr PC_BTP 951.00 4890.67 4898.13 4895.00 4898.27 0.001670 3.09 310.15 102.72 0.27
HEC-RAS Profile: AB 100yr (Continued)
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Reach 7 6006 AB 100yr AB Project 951.00 4889.24 4897.87 4893.73 4897.98 0.000903 2.70 404.80 144.14 0.20
Reach 7 6006 AB 100yr PC 2024 951.00 4889.24 4897.87 4893.73 4897.98 0.000903 2.70 404.80 144.14 0.20
Reach 7 6006 AB 100yr PC_BTP 951.00 4889.24 4897.87 4893.73 4897.98 0.000903 2.70 404.80 144.14 0.20
Reach 7 5865 AB 100yr AB Project 951.00 4888.46 4897.54 4892.82 4897.78 0.001542 3.93 241.81 91.73 0.25
Reach 7 5865 AB 100yr PC 2024 951.00 4888.46 4897.54 4892.82 4897.78 0.001542 3.93 241.81 91.73 0.25
Reach 7 5865 AB 100yr PC_BTP 951.00 4888.46 4897.54 4892.82 4897.78 0.001542 3.93 241.81 91.73 0.25
Reach 7 5818 Bridge
Reach 7 5771 AB 100yr AB Project 951.00 4887.96 4896.72 4892.79 4897.03 0.002045 4.50 211.10 40.81 0.30
Reach 7 5771 AB 100yr PC 2024 951.00 4887.96 4896.72 4892.79 4897.03 0.002045 4.50 211.10 40.81 0.30
Reach 7 5771 AB 100yr PC_BTP 951.00 4887.96 4896.72 4892.79 4897.03 0.002045 4.50 211.10 40.81 0.30
Reach 7 5670 M AB 100yr AB Project 951.00 4890.00 4896.05 4894.71 4896.63 0.006085 6.46 189.28 109.87 0.54
Reach 7 5670 M AB 100yr PC 2024 951.00 4890.00 4896.05 4894.71 4896.63 0.006085 6.46 189.28 109.87 0.54
Reach 7 5670 M AB 100yr PC_BTP 951.00 4890.00 4896.05 4894.71 4896.63 0.006085 6.46 189.28 109.87 0.54
Reach 7 5403 AB 100yr AB Project 951.00 4888.00 4894.56 4892.50 4895.04 0.005517 5.56 170.95 39.97 0.47
Reach 7 5403 AB 100yr PC 2024 951.00 4888.00 4894.56 4892.50 4895.04 0.005517 5.56 170.95 39.97 0.47
Reach 7 5403 AB 100yr PC_BTP 951.00 4888.00 4894.56 4892.50 4895.04 0.005517 5.56 170.95 39.97 0.47
Reach 7 5121 AB 100yr AB Project 951.00 4887.00 4893.64 4890.93 4893.90 0.002830 4.18 263.34 134.35 0.35
Reach 7 5121 AB 100yr PC 2024 951.00 4887.00 4893.64 4890.93 4893.90 0.002830 4.18 263.34 134.35 0.35
Reach 7 5121 AB 100yr PC_BTP 951.00 4887.00 4893.64 4890.93 4893.90 0.002830 4.18 263.34 134.35 0.35
Reach 7 4898 L AB 100yr AB Project 951.00 4886.00 4892.88 4890.57 4893.29 0.002530 5.22 211.16 111.48 0.41
Reach 7 4898 L AB 100yr PC 2024 951.00 4886.00 4892.88 4890.57 4893.29 0.002530 5.22 211.16 111.48 0.41
Reach 7 4898 L AB 100yr PC_BTP 951.00 4886.00 4892.88 4890.57 4893.29 0.002530 5.22 211.16 111.48 0.41
Reach 7 4553 K AB 100yr AB Project 951.00 4885.00 4891.15 4889.77 4891.88 0.007174 6.86 139.42 50.21 0.65
Reach 7 4553 K AB 100yr PC 2024 951.00 4885.00 4891.15 4889.77 4891.88 0.007174 6.86 139.42 50.21 0.65
Reach 7 4553 K AB 100yr PC_BTP 951.00 4885.00 4891.15 4889.77 4891.88 0.007174 6.86 139.42 50.21 0.65
Reach 7 4093 J AB 100yr AB Project 951.00 4882.00 4888.12 4886.88 4888.92 0.005790 7.26 138.39 46.13 0.60
Reach 7 4093 J AB 100yr PC 2024 951.00 4882.00 4888.12 4886.88 4888.92 0.005790 7.26 138.39 46.13 0.60
Reach 7 4093 J AB 100yr PC_BTP 951.00 4882.00 4888.12 4886.88 4888.92 0.005790 7.26 138.39 46.13 0.60
Reach 7 3983 AB 100yr AB Project 951.00 4882.00 4887.97 4885.57 4888.58 0.001206 6.22 152.83 45.94 0.45
Reach 7 3983 AB 100yr PC 2024 951.00 4882.00 4887.97 4885.57 4888.58 0.001206 6.22 152.83 45.94 0.45
Reach 7 3983 AB 100yr PC_BTP 951.00 4882.00 4887.97 4885.57 4888.58 0.001206 6.22 152.83 45.94 0.45
Reach 7 3964 Culvert
Reach 7 3945 AB 100yr AB Project 951.00 4882.00 4886.74 4885.52 4887.68 0.002532 7.77 122.34 44.00 0.63
Reach 7 3945 AB 100yr PC 2024 951.00 4882.00 4886.74 4885.52 4887.68 0.002532 7.77 122.34 44.00 0.63
Reach 7 3945 AB 100yr PC_BTP 951.00 4882.00 4886.74 4885.52 4887.68 0.002532 7.77 122.34 44.00 0.63
Reach 7 3583 I AB 100yr AB Project 951.00 4880.00 4885.89 4883.89 4886.35 0.003672 5.50 172.94 41.84 0.48
Reach 7 3583 I AB 100yr PC 2024 951.00 4880.00 4885.89 4883.89 4886.35 0.003672 5.50 172.94 41.84 0.48
Reach 7 3583 I AB 100yr PC_BTP 951.00 4880.00 4885.89 4883.89 4886.35 0.003672 5.50 172.94 41.84 0.48
Reach 7 3288 H AB 100yr AB Project 951.00 4879.00 4883.89 4883.13 4884.79 0.007720 7.64 127.73 42.71 0.70
Reach 7 3288 H AB 100yr PC 2024 951.00 4879.00 4883.89 4883.13 4884.79 0.007720 7.64 127.73 42.71 0.70
Reach 7 3288 H AB 100yr PC_BTP 951.00 4879.00 4883.89 4883.13 4884.79 0.007720 7.64 127.73 42.71 0.70
Reach 7 3057 AB 100yr AB Project 951.00 4877.16 4881.11 4881.11 4882.40 0.014123 9.53 109.14 43.19 0.94
Reach 7 3057 AB 100yr PC 2024 951.00 4877.16 4881.11 4881.11 4882.40 0.014123 9.53 109.14 43.19 0.94
Reach 7 3057 AB 100yr PC_BTP 951.00 4877.16 4881.11 4881.11 4882.40 0.014123 9.53 109.14 43.19 0.94
Reach 7 2638 G AB 100yr AB Project 951.00 4875.00 4880.24 4876.84 4880.30 0.000520 2.04 466.53 106.64 0.17
Reach 7 2638 G AB 100yr PC 2024 951.00 4875.00 4880.24 4876.84 4880.30 0.000520 2.04 466.53 106.64 0.17
Reach 7 2638 G AB 100yr PC_BTP 951.00 4875.00 4880.24 4876.84 4880.30 0.000520 2.04 466.53 106.64 0.17
Reach 7 2280 AB 100yr AB Project 951.00 4874.00 4879.16 4878.21 4879.78 0.007311 6.45 164.02 85.63 0.60
Reach 7 2280 AB 100yr PC 2024 951.00 4874.00 4879.16 4878.21 4879.78 0.007311 6.45 164.02 85.63 0.60
Reach 7 2280 AB 100yr PC_BTP 951.00 4874.00 4879.16 4878.21 4879.78 0.007311 6.45 164.02 85.63 0.60
Reach 7 1982 F AB 100yr AB Project 951.00 4873.00 4878.07 4877.44 4878.35 0.003082 5.16 291.42 151.55 0.45
Reach 7 1982 F AB 100yr PC 2024 951.00 4873.00 4878.07 4877.44 4878.35 0.003082 5.16 291.42 151.55 0.45
Reach 7 1982 F AB 100yr PC_BTP 951.00 4873.00 4878.07 4877.44 4878.35 0.003082 5.16 291.42 151.55 0.45
Reach 7 1548 E AB 100yr AB Project 951.00 4872.00 4875.30 4875.30 4875.91 0.012170 7.29 184.16 136.42 0.83
Reach 7 1548 E AB 100yr PC 2024 951.00 4872.00 4875.30 4875.30 4875.91 0.012170 7.29 184.16 136.42 0.83
Reach 7 1548 E AB 100yr PC_BTP 951.00 4872.00 4875.30 4875.30 4875.91 0.012170 7.29 184.16 136.42 0.83
Reach 7 1313 AB 100yr AB Project 951.00 4871.00 4874.60 4873.32 4874.65 0.001641 2.28 537.70 282.35 0.27
Reach 7 1313 AB 100yr PC 2024 951.00 4871.00 4874.60 4873.32 4874.65 0.001641 2.28 537.70 282.35 0.27
Reach 7 1313 AB 100yr PC_BTP 951.00 4871.00 4874.60 4873.32 4874.65 0.001641 2.28 537.70 282.35 0.27
Reach 7 1039 D AB 100yr AB Project 951.00 4871.00 4874.28 4872.55 4874.32 0.001195 1.71 629.36 318.86 0.22
Reach 7 1039 D AB 100yr PC 2024 951.00 4871.00 4874.28 4872.55 4874.32 0.001195 1.71 629.36 318.86 0.22
Reach 7 1039 D AB 100yr PC_BTP 951.00 4871.00 4874.28 4872.55 4874.32 0.001195 1.71 629.36 318.86 0.22
Reach 7 979 AB 100yr AB Project 951.00 4869.00 4872.64 4872.35 4873.83 0.005463 8.78 108.36 48.55 0.86
Reach 7 979 AB 100yr PC 2024 951.00 4869.00 4872.64 4872.35 4873.83 0.005463 8.78 108.36 48.55 0.86
Reach 7 979 AB 100yr PC_BTP 951.00 4869.00 4872.64 4872.35 4873.83 0.005463 8.78 108.36 48.55 0.86
HEC-RAS Profile: AB 100yr (Continued)
Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)
Reach 7 963 Culvert
Reach 7 946 AB 100yr AB Project 951.00 4869.00 4871.94 4871.94 4873.38 0.007285 9.63 98.74 56.34 0.99
Reach 7 946 AB 100yr PC 2024 951.00 4869.00 4871.94 4871.94 4873.38 0.007285 9.63 98.74 56.34 0.99
Reach 7 946 AB 100yr PC_BTP 951.00 4869.00 4871.94 4871.94 4873.38 0.007285 9.63 98.74 56.34 0.99
Reach 7 820 C AB 100yr AB Project 951.00 4867.00 4870.29 4869.31 4870.46 0.005318 4.29 321.35 214.71 0.48
Reach 7 820 C AB 100yr PC 2024 951.00 4867.00 4870.29 4869.31 4870.46 0.005318 4.29 321.35 214.71 0.48
Reach 7 820 C AB 100yr PC_BTP 951.00 4867.00 4870.29 4869.31 4870.46 0.005318 4.29 321.35 214.71 0.48
Reach 7 431 B AB 100yr AB Project 951.00 4865.00 4868.87 4868.23 4869.03 0.003729 4.17 382.21 221.65 0.42
Reach 7 431 B AB 100yr PC 2024 951.00 4865.00 4868.87 4868.23 4869.03 0.003729 4.17 382.21 221.65 0.42
Reach 7 431 B AB 100yr PC_BTP 951.00 4865.00 4868.87 4868.23 4869.03 0.003729 4.17 382.21 221.65 0.42
Reach 7 227 AB 100yr AB Project 951.00 4865.00 4868.57 4866.31 4868.59 0.001120 1.61 898.75 363.85 0.17
Reach 7 227 AB 100yr PC 2024 951.00 4865.00 4868.57 4866.31 4868.59 0.001120 1.61 898.75 363.85 0.17
Reach 7 227 AB 100yr PC_BTP 951.00 4865.00 4868.57 4866.31 4868.59 0.001120 1.61 898.75 363.85 0.17
Reach 7 220 Bridge
Reach 7 212 A AB 100yr AB Project 951.00 4864.02 4868.54 4866.30 4868.56 0.001000 1.62 944.03 379.54 0.16
Reach 7 212 A AB 100yr PC 2024 951.00 4864.02 4868.54 4866.30 4868.56 0.001000 1.62 944.03 379.54 0.16
Reach 7 212 A AB 100yr PC_BTP 951.00 4864.02 4868.54 4866.30 4868.56 0.001000 1.62 944.03 379.54 0.16
Appendix E
Culvert Design
HY-8 Culvert Analysis Report
Table 1 - Project Headwater Table
Crossing
Name
Culvert
Name
Discharge
Names
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth
(ft)
Outlet
Control
Depth
(ft)
HW / D
(ft)
Normal
Depth
(ft)
Critical
Depth
(ft)
Outlet
Depth
(ft)
Outlet
Velocity
(ft/s)
Kelley St
- RCP
Culvert 1 100-yr 230.00 230.00 4986.64 4.15 4.236 1.41 3.00 2.46 2.86 8.27
Bypass
Culverts
Culvert 1 Bypass 30.00 30.00 4984.55 1.93 2.052 0.82 1.10 1.31 2.05 3.48
Crossing Input: Kelley St - RCP
Parameter Value Units
DISCHARGE DATA
Discharge Method User-Defined
Discharge List Define...
TAILWATER DATA
Channel Type Trapezoidal Channel
Bottom Width 30.000 ft
Side Slope (H:V) 4.000 _:1
Channel Slope 0.0025 ft/ft
Manning's n (channel) 0.065
Channel Invert Elevation 4981.800 ft
Rating Curve View...
ROADWAY DATA
Roadway Profile Shape Irregular
Irregular Shape Define...
Roadway Surface Paved
Top Width 71.000 ft
Culvert Input: Kelley St - RCP
Parameter Value Units
CULVERT DATA
Name Culvert 1
Shape Circular
Material Concrete
Diameter 3.000 ft
Embedment Depth 0.000 in
Manning's n 0.012
Culvert Type Straight
Inlet Configuration Grooved End Projecting
(Ke=0.2)
Inlet Depression? No
SITE DATA
Site Data Input Option Culvert Invert Data
Inlet Station 0.000 ft
Inlet Elevation 4982.400 ft
Outlet Station 124.000 ft
Outlet Elevation 4981.800 ft
Number of Barrels 4
Computed Culvert Slope 0.004839 ft/ft
Table 2 - Culvert Summary Table: Culvert 1
Discharge
Names
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth
(ft)
Outlet
Control
Depth
(ft)
HW
/ D
(ft)
Flow
Type
Normal
Depth
(ft)
Critical
Depth
(ft)
Outlet
Depth
(ft)
Tailwater
Depth
(ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
10-yr 77.00 77.00 4984.39 1.99 1.177 0.66 1-
S2n
1.29 1.41 1.29 1.55 6.65 1.37
100-yr 230.00 230.00 4986.64 4.15 4.236 1.41 7-
M2t
3.00 2.46 2.86 2.86 8.27 1.94
Overtopping 345.00 268.89 4988.11 4.92 5.712 1.90 4-FFf 3.00 2.62 3.00 3.56 9.51 2.19
Water Surface Profile Plot for Culvert: Culvert 1
Crossing Input: Bypass Culverts
Parameter Value Units
DISCHARGE DATA
Discharge Method User-Defined
Discharge List Define...
TAILWATER DATA
Channel Type Enter Constant Tailwater
Elevation
Channel Invert Elevation 4982.000 ft
Constant Tailwater
Elevation
4984.050 ft
Rating Curve View...
ROADWAY DATA
Roadway Profile Shape Constant Roadway
Elevation
First Roadway Station 0.000 ft
Crest Length 50.000 ft
Crest Elevation 4985.400 ft
Roadway Surface Paved
Top Width 30.000 ft
Culvert Input: Bypass Culverts
Parameter Value Units
CULVERT DATA
Name Culvert 1
Shape Circular
Material Concrete
Diameter 2.500 ft
Embedment Depth 0.000 in
Manning's n 0.013
Culvert Type Straight
Inlet Configuration Square Edge with Headwall
(Ke=0.5)
Inlet Depression? No
SITE DATA
Site Data Input Option Culvert Invert Data
Inlet Station 0.000 ft
Inlet Elevation 4982.500 ft
Outlet Station 60.000 ft
Outlet Elevation 4982.000 ft
Number of Barrels 2
Computed Culvert Slope 0.008333 ft/ft
Table 3 - Culvert Summary Table: Culvert 1
Discharge
Names
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth
(ft)
Outlet
Control
Depth
(ft)
HW
/ D
(ft)
Flow
Type
Normal
Depth
(ft)
Critical
Depth
(ft)
Outlet
Depth
(ft)
Tailwater
Depth
(ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
Bypass 20.00 20.00 4984.26 1.50 1.763 0.71 1-S1t 0.88 1.06 2.05 2.05 2.32 0.00
Bypass 30.00 30.00 4984.55 1.93 2.052 0.82 1-S1t 1.10 1.31 2.05 2.05 3.48 0.00
Overtopping 75.00 59.30 4985.62 3.12 2.711 1.25 5-
S2n
1.68 1.86 1.69 2.05 8.38 0.00
Water Surface Profile Plot for Culvert: Culvert 1
Appendix F
Riprap Design
ERDC TN-EMRRP SR-29 5
Table 2. Permissible Shear and Velocity for Selected Lining Materials1
Boundary Category Boundary Type
Permissible
Shear Stress
(lb/sq ft)
Permissible
Velocity
(ft/sec)
Citation(s)
Soils Fine colloidal sand 0.02 - 0.03 1.5 A
Sandy loam (noncolloidal) 0.03 - 0.04 1.75 A
Alluvial silt (noncolloidal) 0.045 - 0.05 2 A
Silty loam (noncolloidal) 0.045 - 0.05 1.75 – 2.25 A
Firm loam 0.075 2.5 A
Fine gravels 0.075 2.5 A
Stiff clay 0.26 3 – 4.5 A, F
Alluvial silt (colloidal) 0.26 3.75 A
Graded loam to cobbles 0.38 3.75 A
Graded silts to cobbles 0.43 4 A
Shales and hardpan 0.67 6 A
Gravel/Cobble 1-in. 0.33 2.5 – 5 A
2-in. 0.67 3 – 6 A
6-in. 2.0 4 – 7.5 A
12-in. 4.0 5.5 – 12 A
Vegetation Class A turf 3.7 6 – 8 E, N
Class B turf 2.1 4 - 7 E, N
Class C turf 1.0 3.5 E, N
Long native grasses 1.2 – 1.7 4 – 6 G, H, L, N
Short native and bunch grass 0.7 - 0.95 3 – 4 G, H, L, N
Reed plantings 0.1-0.6 N/A E, N
Hardwood tree plantings 0.41-2.5 N/A E, N
Temporary Degradable RECPs Jute net 0.45 1 – 2.5 E, H, M
Straw with net 1.5 – 1.65 1 – 3 E, H, M
Coconut fiber with net 2.25 3 – 4 E, M
Fiberglass roving 2.00 2.5 – 7 E, H, M
Non-Degradable RECPs Unvegetated 3.00 5 – 7 E, G, M
Partially established 4.0-6.0 7.5 – 15 E, G, M
Fully vegetated 8.00 8 – 21 F, L, M
Riprap 6 – in. d50 2.5 5 – 10 H
9 – in. d50 3.8 7 – 11 H
12 – in. d50 5.1 10 – 13 H
18 – in. d50 7.6 12 – 16 H
24 – in. d50 10.1 14 – 18 E
Soil Bioengineering Wattles 0.2 – 1.0 3 C, I, J, N
Reed fascine 0.6-1.25 5 E
Coir roll 3 - 5 8 E, M, N
Vegetated coir mat 4 - 8 9.5 E, M, N
Live brush mattress (initial) 0.4 – 4.1 4 B, E, I
Live brush mattress (grown) 3.90-8.2 12 B, C, E, I, N
Brush layering (initial/grown) 0.4 – 6.25 12 E, I, N
Live fascine 1.25-3.10 6 – 8 C, E, I, J
Live willow stakes 2.10-3.10 3 – 10 E, N, O
Hard Surfacing Gabions 10 14 – 19 D
Concrete 12.5 >18 H
1 Ranges of values generally reflect multiple sources of data or different testing conditions.
A. Chang, H.H. (1988). F. Julien, P.Y. (1995). K. Sprague, C.J. (1999).
B. Florineth. (1982) G. Kouwen, N.; Li, R. M.; and Simons , D.B., (1980). L. Temple, D.M. (1980).
C. Gerstgraser, C. (1998). H. Norman, J. N. (1975). M. TXDOT (1999)
D. Goff, K. (1999). I. Schiechtl, H. M. and R. Stern. (1996). N. Data from Author (2001)
E. Gray, D.H., and Sotir, R.B. (1996). J. Schoklitsch, A. (1937). O. USACE (1997).
Front Range Storage
Preliminary Drainage Report
23
APPENDIX F – MAPS
A
W
e
s
t
r
i
a
n
C
o
m
p
a
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y
LEGEND
Know what's below.
before you dig.Call
R
A
W
e
s
t
r
i
a
n
C
o
m
p
a
n
y
Know what's below.
before you dig.Call
R
KE
L
L
E
Y
S
T
R
E
E
T
A
W
e
s
t
r
i
a
n
C
o
m
p
a
n
y
Know what's below.
before you dig.Call
R
Front Range Storage
Preliminary Drainage Report
24
APPENDIX G –LID EXHIBIT
A
W
e
s
t
r
i
a
n
C
o
m
p
a
n
y
Know what's below.
before you dig.Call
R
LID TREATMENT
KELLEY STREET