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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
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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
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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. _______
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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
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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.
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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.
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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
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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.
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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:
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• 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
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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
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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.
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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
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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
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2
5
COUNTY RD 48
BO
X
E
L
D
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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
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0 200'400'
SCALE: 1" = 200'
100'
LEGEND:
47768
5062
SURVEY CONTROL NOTES:
4974
EF
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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).