HomeMy WebLinkAboutFRONT RANGE STORAGE - PDP230011 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
FOR
Front Range RV and Boat Storage
Prepared For:
Freedom Homes, LLC
4920 Saddlewood Circle.
Johnstown, Colorado 80534
Eric Kelley
(970) 405-3961
January 25, 2024
Project No. 39817.00
Prepared By:
JR Engineering, LLC
2900 South College Avenue, Suite 3D
Fort Collins, CO 80525
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TABLE OF CONTENTS
TABLE OF CONTENTS ......................................................................................................................... ii
APPENDIX ..................................................................................................................................... iii
Engineer’s Certification Block ........................................................................................................... iv
GENERAL DESCRIPTION AND LOCATION ............................................................................................ 1
LOCATION ..................................................................................................................................... 1
DESCRIPTION OF PROPERTY .......................................................................................................... 1
MASTER DRAINAGE BASIN DESCRIPTION ....................................................................................... 1
FLOODPLAIN SUBMITTAL REQUIREMENTS ..................................................................................... 2
DRAINAGE BASINS AND SUB-BASINS ................................................................................................. 2
MAJOR BASINS AND SUB-BASINS ................................................................................................... 2
EXISTING SUB-BASIN DESCRIPTION ................................................................................................ 2
EXISTING OFF-SITE DRAINAGE BASINS ........................................................................................... 2
PROPOSED SUB-BASINS DESCRIPTIONS ......................................................................................... 3
OFFSITE SUB-BASINS DESCRIPTIONS .............................................................................................. 4
PROJECT DESCRIPTION ...................................................................................................................... 4
PROJECT DESCRIPTION .................................................................................................................. 4
PROPOSED DRAINAGE FACILITIES ...................................................................................................... 4
GENERAL CONCEPT ....................................................................................................................... 4
WATER QUALITY/ DETENTION FACILITIES ...................................................................................... 5
LOW IMPACT DEVELOPMENT ........................................................................................................ 5
DRAINAGE DESIGN CRITERIA ............................................................................................................. 6
REGULATIONS ............................................................................................................................... 6
FOUR STEP PROCESS TO PROTECT RECEIVING WATERS ................................................................. 6
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS ............................................................. 7
HYDROLOGIC CRITERIA .................................................................................................................. 7
HYDRAULIC CRITERIA ..................................................................................................................... 7
FLOODPLAIN REGULATIONS COMPLIANCE ..................................................................................... 7
MODIFICATIONS OF CRITERIA ........................................................................................................ 8
EROSION CONTROL ....................................................................................................................... 8
CONCLUSIONS ................................................................................................................................... 8
COMPLIANCE WITH STANDARDS ................................................................................................... 8
DRAINAGE CONCEPT ..................................................................................................................... 9
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APPENDIX
Appendix A – Figures
Appendix B – Hydrologic Calculations
Appendix C – Hydraulic Calculations
Appendix D – Water Quality Calculations
Appendix E – Reference
Appendix F – Maps
Appendix G – LID Exhibit
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Engineer’s Certification Block
I hereby attest that this report for the final drainage design for the Front Range RV Boat and Storage was
prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins
Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume
liability for drainage facilities designed by others.
Joseph Martin Frank, PE
Registered Professional Engineer
State of Colorado No. 53399
For and on behalf of JR Engineering
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GENERAL DESCRIPTION AND LOCATION
LOCATION
The site is located in the North half of the Northwest Quarter and the East Half of Section 3, Township
7 North, Range 68 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of
Colorado. More specifically, the site is a 105-acre property that is zoned I-Industrial. The concept plan
proposes approximately 12 acres of outdoor, non-covered recreational vehicle and boat storage. The
remaining 95 acres will remain for agricultural use. The site is situated on the NE Frontage Rd on the
West side and is bordered by the Larimer and Weld County Canal (“LWCC”) on the south side. To the
East, the site abuts four presently vacant parcels of land, while to the North, it borders the land owned
by the Colorado Division of Wildlife.
DESCRIPTION OF PROPERTY
The Front Range Storage area spans approximately 105 acres, with approximately 12 acres designated for
development into RV and boat storage, along with off-site detention. The remaining 95 acres will continue
to be used as irrigated agricultural land. The site currently features an existing gravel road access located
just off the NE Frontage road. Most of the site remains undeveloped and is presently being utilized for
agriculture and a U-haul rental service. Two buildings are the only existing structures on site, situated just
east of the Frontage Road. Although flow paths are not precisely defined, the general drainage pattern of
the site follows a gradual slope ranging from 1% to 4% in the northeast to the southwest direction.
According to the Natural Resources Conservation Service (NRCS), approximately half of the soils on the
site are composed of type B soils, which have a mild infiltration and runoff rate. The remaining site is made
up of Type C soils, which are characterized by a lower infiltration rate and corresponding higher runoff
rates. For additional information, refer to the NRCS soil map within Appendix A of this report. Adjacent
to the proposed site, a pre-existing 15” corrugated metal pipe facilitates the drainage of any surplus
stormwater and irrigation water from the site into the Larimer and Weld Canal. The existing culvert is
not capable of conveying large quantities of runoff.
MASTER DRAINAGE BASIN DESCRIPTION
The site is positioned within the Boxelder Creek Basin and shares borders with the Upper Cooper Slough
and Lower Cooper Slough basins. The Boxelder Creek watershed and associated floodplain consists to a
large degree of mostly undeveloped land. Based on the 100-year rainfall event, a detention pond will be
built southeast of the RV and boat storage facility. Currently, the site drains through a 15” CMP and
outfalls into the Larimer and Weld Canal. The detention pond is designed to incorporate a trickle channel
and will feature an outfall leading to Boxelder Creek just east of the site. The Larimer and Weld County
Canal policy as of 2024 is to not accept stormwater runoff from any new developments.
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FLOODPLAIN SUBMITTAL REQUIREMENTS
The Front Range RV Boat and Storage site is on FEMA FIRM panels 08069C0982F and 08069C1001F. The
Front Range RV Boat and Storage site lies within FEMA Zone X, areas that are determined to be outside
the 0.2% annual chance floodplain. The Front Range RV Boat and Storage site is not located within a FEMA
regulated floodplain, as shown in Appendix A in the FEMA attachments. The site is also not located in the
City of Fort Collins Floodplain, as shown in Appendix A in the City of Fort Collins Flood map. The site
does drain into the Boxelder Creek Floodplain Zone AE.
DRAINAGE BASINS AND SUB-BASINS
MAJOR BASINS AND SUB-BASINS
The Front Range RV Boat and Storage site is located in the Boxelder Creek Basin. The Upper and Lower
Cooper Slough Basins exist to the west of the site. Covering approximately 265 square miles, the Boxelder
Creek extends from north of the Colorado/Wyoming border and stretch southward into the eastern part
of Fort Collins. These basins are predominantly characterized by farmland, with occasional pockets of
mixed-use residential development and limited commercial development.
EXISTING SUB-BASIN DESCRIPTION
Basin EO1, 12.51 acres and 8.2% impervious this basin, is composed of the proposed RV Boat
and storage site.
Basin EX2, 36.9 acres and 2% impervious this basin, is composed the portion of the site east of
the proposed RV Boat and Storage site.
Basin EX3, 19.8 acres and 2% impervious this basin, is composed the portion of the site east of
the proposed RV Boat and Storage site.
EXISTING OFF-SITE DRAINAGE BASINS
Currently, the site collects off-site runoff from the north from the Colorado Division of Wildlife property
just north of the 1435 NE Frontage Road that drains onto the site via sheet flow. That runoff drains
directly into the Larimer and Weld Canal. Runoff from the eastern off-site basin drains south and into the
Larimer and Weld Canal. A ridgeline divides portions of the northeast and southeast off-site basins. This
ridgeline divides the water such that everything west of the ridgeline drains into the Larimer and Weld
Canal while everything east of the ridgeline drains into the Boxelder Creek. In the 100-year event, it is
anticipated that the runoff from the North and along the NE Frontage Road and sheet drain onto the site.
This runoff has been previously modeled as part of the Boxelder Creek LOMR as built SWMM model. An
exhibit showing the corresponding model has been provided in Appendix D of this report. JR Engineering
is not changing the upstream hydrology and is modeling the offsite runoff adjacent to the Frontage based
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on the average from between SWMM link elements 299 and 99, as shown in the Existing SWMM exhibit
provided in Appendix F of this report.
PROPOSED SUB-BASINS DESCRIPTIONS
Basin C1, 0.36 acres and 61.5% impervious this basin, is composed of the access to the site off
the I-25 North East Frontage Road.
Basin C2 is 0.96 acres and 70.0% impervious. This basin is composed of the site entrance on the
frontage road, and access improvements. The runoff from this basin drains to an onsite at design
point C2 where it goes to the onsite detention pond.
Basin C3 is 2.52 acres and 71.9% impervious. This basin is composed of uncovered parking, paved
drive isles, and some vegetation. The runoff from this basin will be conveyed to a rain garden at
design point 3.
Basin C4 is 1.20 acres and 78.5% impervious. This basin is composed of uncovered parking, paved
drive isles, and some vegetation. The runoff will go into a rain garden at design point 3 where it
will then be conveyed to the detention pond.
Basin C5 is 1.19 acres and 78.2% impervious. This basin is composed of uncovered parking and
paved drive isles. The runoff will go into a rain garden at design point 5 where it will then be
conveyed to the detention pond.
Basin C6 is 1.31 acres and 77.3% impervious. This basin is composed of uncovered parking and
paved drive isles. The runoff will go into a rain garden at design point 6 where it will then be
conveyed to the detention pond.
Basin C7 is 0.42 acres and 67.5% impervious. This basin is composed of uncovered parking and
paved drive isles. The runoff will go into a rain garden at design point 7, where it will then be
conveyed to the detention pond.
Basin C8, 1.73 acres and 77.4% impervious this basin will be composed of uncovered parking and
paved drive isles. The runoff will go into a rain garden at design point 8, where it will then be
conveyed to the detention pond.
Basin C9, 0.42 acres and 38.0% impervious this basin will be composed of the drainage swale on
the southern portion of the site.
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Basin C10, 2.18 acres and 4% impervious this basin will be composed the detention / water quality
pond.
OFFSITE SUB-BASINS DESCRIPTIONS
Basin OS1, 0.42 acres and 100.0% impervious this basin, is composed of the I-25 North East
Frontage Road.
Basin OS2 is 1.02 acres and 8.2% impervious. This basin is composed of walk and a grass lined
channel that conveys offsite runoff that drains historically drains to the Larimer and Weld Canal.
Basin OS3 is 37.23 acres and 2.1% impervious. This basin drains to a pond where it then outfalls
into Box Elder Creek, by overtopping the weir from the outlet structure.
Basin OS4 is 20.31 acres and 2% impervious. This basin drains to a swale, where it then outfalls
into Box Elder Creek.
PROJECT DESCRIPTION
PROJECT DESCRIPTION
Front Range RV & Boat Storage site is a recreational vehicle and boat storage facility at 1312 NE
Frontage Road. The previously undeveloped portion of the 105-acre property, approximately 12
acres, is for outdoor covered and uncovered recreational vehicle and boat storage. The remaining
95 acres will remain for agricultural use. The property will hold detention and water quality for
the Front Range RV & Boat Storage development.
PROPOSED DRAINAGE FACILITIES
GENERAL CONCEPT
The proposed development to the Front Range RV & Boat Storage site will result in the
developed condition being treated for water quality and detained. Low-impact development best
management practices are proposed to improve the quality of runoff and aid in reducing peak
flows. Specifically, a linear bio-retention swale will be used in the southern portion of the site to
treat and provide water quality, while the remaining portion of the site will be treated in the
proposed detention pond. Runoff from the site sheet drains down the drive isles on the south
side of the site. From then on, the runoff is conveyed in a swale to the detention pond. Surface
overflow paths will be provided such that the 100-year storm flows remain at least one foot
below the finished floor elevation at the time of the final drainage report.
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WATER QUALITY/ DETENTION FACILITIES
The site includes a Rain Garden designed to capture and address 82% of the total water quality
capture volume on the site. The Rain Garden will be maintained to ensure the ongoing protection
of the receiving waters. An additional 12% of the water quality capture volume on the site will
undergo water quality treatment in the water quality/detention pond. The detention pond will
release at the 2- year historic event the 100 year event.
Currently, the runoff from the I-25 Frontage Road is untreated and flows into a swale, leading to
the LWCC. Approximately 6% of the impervious area along the I-25 Frontage Road remains
untreated due to the existing grade of the road. However, the runoff from this road will be
directed into a swale, functioning similarly to a bio-retention swale during water quality events
due to its shallow slope and low flow. Refer to the water quality map in Appendix G for more
details.
It is important to note that the site does not treat 100% of the modified/added impervious areas.
Specifically, around 0.20 acres of new impervious area resulting from the frontage road widening
and adjacent sidewalk in basins OS1 & OS2 will not be conveyed through the proposed
development for water quality treatment. Nonetheless, the proposed development plans to treat
approximately 0.21 acres of existing frontage road impervious area runoff in basins C1 & C2,
which would have originally followed its historic drainage path into the Larimer and Weld Canal.
By addressing these areas, the total treated impervious area meets the modified/added
impervious areas, as illustrated in the LID exhibit in Appendix G of this report.
LOW IMPACT DEVELOPMENT
A minimum of 75% - percent of the new impervious surface area is treated by a Low-Impact
Development (LID) best management practice (BMP) in accordance with City criteria. An
illustrative LID/ Surface Map is provided in Appendix G, and the sizing of the LID methods is
provided in Appendix D.
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DRAINAGE DESIGN CRITERIA
REGULATIONS
This report was prepared to meet or exceed the City of Fort Collins stormwater criteria. The
City of Fort Collins Stormwater Criteria Manual (dated 2018)(FCSCM) and the Urban Drainage
Flood Control District’s (UDFCD) Drainage Criteria Manual (USDCM) Volumes 1, 2 and 3 were
referenced as guidelines for this design.
FOUR STEP PROCESS TO PROTECT RECEIVING WATERS
The City of Fort Collins requires the Four Step Process to protect receiving waters. The four-
step process incorporates reducing runoff volume, treating water quality capture volume,
stabilizing streams, and implementing long-term source controls. Volume reduction is an
important part of the Four Step Process and is fundamental to effective stormwater management.
Per City criteria, a minimum of 75 percent of new impervious surface area must be treated by a
Low-Impact Development (LID) best management practice (BMP). The site incorporates a Rain
Garden and a water quality pond designed to capture and treat at least 75% of the site’s water
quality capture volume. The Rain Garden needs to be properly cleaned and maintained to allow
for long-term protection of the receiving waters. The proposed LID BMPs will have the effect of
slowing runoff through the site lot and increasing infiltration and rainfall interception by
encouraging infiltration and careful selection of vegetative cover. The LID exhibit is shown within
Appendix G of this report.
Step 1 – Employ Runoff Reduction Practices
The majority of the developed runoff through the site will be routed through the site. The
detention pond will restrict the flow rate of stormwater leaving the site and reduce the impact
on downstream drainage areas. Additionally, the design will allow for greater that 75% of the
project is added impervious area to be routed through an approved LID water quality treatment
train. The onsite water quality BMPs include a Rain Garden and a water-quality pond.
Step 2 – Implement BMPS that Provides Water Quality Capture Volume
The site incorporates a Rain Garden designed to capture and treat 82% of the site’s water quality
capture volume. The Rain Garden will need to be properly cleaned and maintained to allow for
long-term protection of the receiving waters. 12% of the site’s water quality capture volume will
be treated in the water quality/detention pond. In the existing condition, the runoff from the I-
25 Frontage Road is untreated and drains into a swale to the LWCC. 6% of the site’s impervious
area along the I-25 Frontage Road will be untreated due to the existing grade of the Frontage
Road. However, the runoff from the frontage road will drain into a swale, which will act similarly
to a bio-retention swale in a water quality event due to the shallow slope and low amount of
flow. For additional information, see the water quality map in Appendix G of this Report.
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Step three –Stabilize Drainage ways
The stormwater improvements for the Front Range RV Boat and Storage improve the existing
condition by eliminating, reducing, and detaining flows.
Step four – Implement site-specific and other source control BMPs
Water quality will ultimately treated in the Rain Garden for 82% of the site. The remaining treated
portion of the site will then be treated in the water quality / detention facility, which will serve
to treat a portion of the site for water quality. An erosion control plan and Stormwater
Management Plan will be implemented to prevent erosion and control sediment on the project
site and downstream drainage ways during and after construction.
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
The as-built SWMM model from the 2018 Boxelder LOMR was used to determine the existing runoff
going through the site. The 2018 as-built SWMM model takes into account improvements that have been
built upstream of the site i.e. (the East Side Detention Facility).
JR Engineering verified the 100-year water surface elevation of the Larimer and Weld Canal by running
the L&W Canal HEC_RAS model from the 2018 LOMR by Ayres and Associates at an unsteady 100-year
analysis and modeled the results with the same version of HEC-RAS 5.02 that was utilized to generate the
results for the LOMR. The 100-year wselv. of the canal is contained within the canal. For more additional
information regarding the canal and pond invert, refer to the annotated Figure 5.1 in Appendix E.
Groundwater measurements were taken throughout the site over a period from the fall of 2022 to the
spring of 2023 to determine the ground water level. The invert of the pond is approximately 2’ above the
groundwater, as shown in the attached experts from the geotechnical report in Appendix E of this report.
JR Engineering designed the pond to detain the proposed 100-year event. JR Engineering calculated the
required detention volume by detaining the 100-year event and releasing at the 2-year event by modeling
the release rate with the FFA method, as shown in Appendix C. For the preliminary design of the outlet
structure, JR Engineering used the MHFD-Detention Workbook to size the orifices for the water quality
portion of the site treated in the detention pond. The outlet structure was preliminary sized and a rating
curve was developed, as shown in Appendix C.
Table 1, as shown below, shows the 100-year volume.
Table 1:Required Pond Volume
Pond
ID
100-YR_Vol.
(Acre-Ft)
WQ
Capture -Pond
(Acre-Ft)
Total Volume
(Acre-Ft)
PEAK_POND
RELEASE (CFS)POND
INVERT
P1 2.173 0.049 2.222 4.5 4977.43
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Table 2: Pond Stage Discharge
The pond detains the proposed 100-year event and releases at or below the 2-year historic release rate.
The Detention volume was calculated using the FFA method. The spillway for the pond will be designed
at time of final.
HYDROLOGIC CRITERIA
Weighted percent imperviousness was calculated for each basin using the Fort Collins Stormwater
Criteria Manual Table 3.2-2 for each basin. The FFA method was used to determine the detention volume
since the site is less than 20 acres. The City of Fort Collins area has rainfall depths associated with the
table below, as shown in Chapter 5 of the Fort Collins Stormwater Criteria Manual.
HYDRAULIC CRITERIA
At time of the Final Plan (FP) StormCAD will be utilized to determine the hydraulic capacity of the storm
sewer system on site. Additionally, hydraulic calculations for items such as street capacity, inlet capacity,
swales, channels, and the emergency spillway will be provided within the Final Drainage Report.
FLOODPLAIN REGULATIONS COMPLIANCE
As previously stated, the Front Range RV and Boat Storage site lies within FEMA Zone X, areas that are
determined to be outside the 0.2% annual chance floodplain. The site is not located within a FEMA-
regulated floodplain, as shown in Appendix A in the FEMA attachments. The site is also not located in the
Cities of Fort Collins Floodplain, as shown in Appendix A in the City of Fort Collins Flood map.
Stage Area Area Volume Volume Total
Outflow
[ft][ft 2][acres][ft 3][ac-ft][cfs]
0.00 37 0.001 0 0.000 0.00
0.50 4,211 0.097 1,062 0.024 0.02
0.66 9,441 0.217 2,154 0.049 0.02
1.00 20,556 0.472 7,253 0.167 0.23
1.50 44,063 1.012 23,408 0.537 1.53
2.00 62,966 1.445 50,165 1.152 2.87
2.50 76,326 1.752 84,988 1.951 3.66
2.68 78,712 1.807 98,942 2.271 3.97
2.75 79,641 1.828 104,484 2.399 5.45
3.00 82,955 1.904 124,808 2.865 12.96
3.25 85,628 1.966 145,881 3.349 13.64
3.30 86,163 1.978 150,176 3.448 13.77
3.40 87,232 2.003 158,846 3.647 14.03
3.50 88,302 2.027 167,623 3.848 14.29
Invert - 4977.47
WQ Volume -4978.13
Outlet Structure Overflow Weir - 4980.15
Stage - Storage
Description
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MODIFICATIONS OF CRITERIA
The site does not treat 100% of modified/added impervious areas. Approximately 0.20 acres of new
impervious area from the frontage road widening and adjacent sidewalk located within basins OS1 & OS2
is not being conveyed through the proposed development and treated for water quality. However, the
proposed development will be treating approximately 0.21 acres of existing frontage road impervious area
runoff located within basins C1 & C2 that would have otherwise been directed along its historic drainage
path and into the Larimer and Weld Canal. By offsetting these areas, the total amount of impervious area
being treated exceeds the modified/added impervious areas, as shown in the LID exhibit in Appendix G
of this report.
No new developments are being allowed to discharge developed runoff into the Larimer and Weld Canal.
As a result, the only outfall option for the site is Boxelder Creek, which is located just east of the site. In
order to retain the existing house as is, an open swale with a slope less than the minimum 0.50% is being
proposed. The swale running along the south side of the storage facility has a longitudinal slope of 0.40%.
The slope of the swale from the southeast corner of the facility all the way to the outfall in Boxelder
Creek is 0.25%. These swales do have a concrete trickle pan at the bottom. The open swale will make
routine maintenance easier and create a future outfall option for the remaining undeveloped portions of
the site.
JR Engineering is proposing that the detention pond storm outfall go underneath a 24" water transmission
line owned by ELCO via an inverted siphon. This 24” waterline is a water transmission line, and therefore
lowering it is not a feasible option. The sediment built up within the storm line will be cleaned by a Jet-
Vac, and the owner of the site will be responsible for the maintenance of the storm outfall pipe. The outfall
will primarily be driven by head from the onsite detention facility.
EROSION CONTROL
A statement of compliance with Erosion Control Criteria and all Erosion Control Materials will be
provided with the Final Drainage Report.
CONCLUSIONS
COMPLIANCE WITH STANDARDS
The hydrologic and water quality calculations were performed using the required methods as outlined in
the City of Fort Collins Storm Water Criteria Manual. The proposed drainage improvements meet or
exceed the City’s requirements except for the parameters presented in the Modification to Criteria
section of this Report.
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DRAINAGE CONCEPT
The proposed concept for the development of the RV Boat storage site involves surface flows and running
swales. The site runoff will be treated at the detention facility onsite. All the off-site flows will be conveyed
through the site. The existing conditions drainage patterns are maintained in the proposed. The proposed
improvements will have no adverse impacts on the flow rate, character, or quality of runoff leaving the
site.
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REFERENCES
Fort Collins Stormwater Criteria Manual; City of Fort Collins, Colorado, December 2018.
Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3); Urban Drainage and Flood Control District,
June 2001.
Hydrologic Analysis of the Box Elder Creek/ Cooper Slough Watershed Icon Engineering, Apr. 2014.
Boxelder and Cooper Slough Letter of Map Revision (LOMR) for the Boxelder 6 Project."AYRES &
ASSOCIATES, 5 Nov. 2018.
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APPENDIX A – FIGURES
A Westrian Company
Hydrologic Soil Group—Larimer County Area, Colorado
(Mountain Vista Property)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 1 of 4
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40° 36' 26'' N
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 300 600 1200 1800
Feet
0 50 100 200 300
Meters
Map Scale: 1:6,250 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 17, Sep 7, 2022
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug 25,
2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—Larimer County Area, Colorado
(Mountain Vista Property)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
7 Ascalon sandy loam, 0
to 3 percent slopes
B 14.8 14.5%
53 Kim loam, 1 to 3 percent
slopes
B 26.5 25.9%
54 Kim loam, 3 to 5 percent
slopes
B 16.6 16.2%
73 Nunn clay loam, 0 to 1
percent slopes
C 23.8 23.2%
74 Nunn clay loam, 1 to 3
percent slopes
C 10.1 9.9%
94 Satanta loam, 0 to 1
percent slopes
C 0.2 0.2%
95 Satanta loam, 1 to 3
percent slopes
C 10.2 10.0%
105 Table Mountain loam, 0
to 1 percent slopes
B 0.1 0.1%
Totals for Area of Interest 102.4 100.0%
Hydrologic Soil Group—Larimer County Area, Colorado Mountain Vista Property
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 3 of 4
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado Mountain Vista Property
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/17/2023
Page 4 of 4
18,056
3,009.3
FCMaps
This map is a user generated static output from the City of Fort Collins FCMaps
Internet mapping site and is for reference only. Data layers that appear on this
map may or may not be accurate, current, or otherwise reliable.
City of Fort Collins - GIS
2,286.0
1:
WGS_1984_Web_Mercator_Auxiliary_Sphere
Feet2,286.001,143.00
Notes
Legend
13,719
FEMA Floodplain
FEMA High Risk - Floodway
FEMA High Risk - 100 Year
FEMA Moderate Risk - 100 / 500 Year
City Floodplains
City High Risk - Floodway
City High Risk - 100 Year
City Moderate Risk - 100 Year
City Limits
World Hillshade
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mileZone X
Future Conditions 1% Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood HazardZone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 7/21/2023 at 10:33 AM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
B 20.2
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
105°0'6"W 40°36'26"N
104°59'29"W 40°35'58"N
Basemap Imagery Source: USGS National Map 2023
9,028
1,504.7
FCMaps
This map is a user generated static output from the City of Fort Collins FCMaps
Internet mapping site and is for reference only. Data layers that appear on this
map may or may not be accurate, current, or otherwise reliable.
City of Fort Collins - GIS
1,143.0
1:
WGS_1984_Web_Mercator_Auxiliary_Sphere
Feet1,143.00571.50
Notes
Legend
6,859
Street Names
FEMA Floodplain
FEMA High Risk - Floodway
FEMA High Risk - 100 Year
FEMA Moderate Risk - 100 / 500 Year
City Floodplains
City High Risk - Floodway
City High Risk - 100 Year
City Moderate Risk - 100 Year
City Limits
Front Range Storage
Preliminary Drainage Report
12
APPENDIX B – HYDROLOGIC CALCULATIONS
Subdivision:RV & Boat Storage Project Name:Mountain Vista Property
Location:Fort Collins Project No.:
Calculated By:JSC
Checked By:ARJ
Date:1/30/23
EO1 12.51 40%1.88 6.0%90%0.05 0.4%2%10.57 1.7%90%0.02 0.1%8.2%
EX2 36.90 40%0.00 0.0%90%0.00 0.0%2%36.90 2.0%90%0.00 0.0%2.0%
EX3 19.80 40%0.00 0.0%90%0.00 0.0%2%19.80 2.0%90%0.00 0.0%2.0%
TOTAL 49.41 40%1.88 1.5%90%0.05 0.1%2%47.47 1.9%90%0.02 0.0%3.6%
Basins Total
Weighted %
Imp.
Asphalt/Concrete
% Imp.Area (ac)Weighted
% Imp.
COMPOSITE % IMPERVIOUS CALCULATIONS
Weighted
% Imp.Basin ID Total Area (ac) % Imp. Area (ac)
Landscape or Previous Surface
% Imp. Area (ac)Weighted %
Imp.
Gravel Rooftop
Weighted
% Imp.% Imp. Area (ac)
39817.00
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 2 1/30/2024
UPDATED BASIN ASPHALT/CONCRETE
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 2 of 2 1/30/2024
Subdivision:RV & Boat Storage Project Name:Mountain Vista Property
Location:Fort Collins Project No.:
Calculated By:JSC
Checked By:ARJ
Date:1/30/23
EO1 12.51 0.50 1.88 0.08 0.09 0.95 0.05 0.00 0.00 0.20 10.57 0.17 0.21 0.95 0.02 0.00 0.00 0.17 0.22
EX2 36.90 0.50 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.20 36.90 0.20 0.25 0.95 0.00 0.00 0.00 0.20 0.25
EX3 19.80 0.50 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.20 19.80 0.20 0.25 0.95 0.00 0.00 0.00 0.20 0.25
Basin ID
Basins Total
Weighted 100
YEAR C
COMPOSITE RUNOFF COEFFICIENT CALCULATIONS
Basins Total
Weighted 2
YEAR CArea (ac)2 -
YEAR C
100 -
YEAR C
Runoff
Coefficient Area (ac)2 -
YEAR C
100 -
YEAR C
39817.00
Total Area
(ac)Runoff
Coefficient Area (ac)Area (ac)
Gravel Rooftop Landscape or Previous Surface
Runoff
Coefficient
Asphalt/Concrete
2 -
YEAR C
100 -
YEAR C
2 -
YEAR C
100 -
YEAR C
Runoff
Coefficient
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Subdivision:RV & Boat Storage Project Name:Mountain Vista Property
Location:Fort Collins Project No.:
Calculated By:JSC
Checked By:ARJ
Date:1/30/23
BASIN D.A. Hydrologic Impervious C2 C100 L S o t i - 2 Year t i - 100 Year L t S t K VEL.t t COMP.t c-2 Year COMP.t c 100 - Year TOTAL Tc t i - 2 Year t c- 100 Year
ID (ac) Soils Group (%)(ft)(%)(min)(min)(ft)(%)(ft/s)(min)(min)(min)LENGTH (ft)Check (min)(min)
EO1 12.51 B/C 8%0.17 0.22 100 0.6%93.6 89.2 200 1.0%5.0 0.5 6.7 100.3 95.9 300.0 11.7 12.0 12.0
EX2 36.9 B/C 2%0.20 0.25 100 1.0%76.9 72.7 800 1.8%5.0 0.7 19.9 96.8 92.5 900.0 15.0 15.0 15.0
EX3 19.8 B/C 2%0.20 0.25 100 1.0%76.9 72.7 713 1.0%5.0 0.5 24.0 100.9 96.7 813.0 14.5 15.0 15.0
Notes:
Velocity V = K*St^0.5
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN
39817.00
FINAL(URBANIZED BASINS)
tc CHECK
DATA
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Project Name:Mountain Vista Property
Subdivision:RV & Boat Storage Project No.:
Location:Fort Collins Calculated By:JSC
Design Storm:Checked By:ARJ
Date:
TRAVEL TIME
STREET
De
s
i
g
n
P
o
i
n
t
Ba
s
i
n
I
D
Ar
e
a
(
A
c
)
Ru
n
o
f
f
C
o
e
f
f
.
tc
(
m
i
n
)
-
2
Y
E
A
R
C*
A
(
A
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
tc
(
m
i
n
)
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
Qst
r
e
e
t
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Qpi
p
e
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Pi
p
e
S
i
z
e
(
i
n
c
h
e
s
)
Le
n
g
t
h
(
f
t
)
Ve
l
o
c
i
t
y
(
f
p
s
)
tt
(
m
i
n
)
REMARKS
1 EO1 12.51 0.17 12.0 2.18 2.05 4.5
1 EX2 36.90 0.20 15.0 7.38 1.87 13.8
1.1 12.0 9.56 2.05 19.6
3 EX3 19.80 0.20 15.0 3.96 1.87 7.4
Notes:
Street and Pipe C*A values are determined by Q/I using the catchment's intensity value.
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
39817.00
1/30/23
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Project Name:Mountain Vista Property
Subdivision:RV & Boat Storage Project No.:
Location:Fort Collins Calculated By:JSC
Design Storm:Checked By:ARJ
Date:
TRAVEL TIME
STREET
De
s
i
g
n
P
o
i
n
t
Ba
s
i
n
I
D
Ar
e
a
(
a
c
)
Ru
n
o
f
f
C
o
e
f
f
.
tc
(
m
i
n
)
-
1
0
0
Y
e
a
r
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
tc
(
m
i
n
)
C*
A
(
a
c
)
I
(
i
n
/
h
r
)
Q
(
c
f
s
)
Qst
r
e
e
t
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Qpi
p
e
(
c
f
s
)
C*
A
(
a
c
)
Sl
o
p
e
(
%
)
Pi
p
e
S
i
z
e
(
i
n
c
h
e
s
)
Le
n
g
t
h
(
f
t
)
Ve
l
o
c
i
t
y
(
f
p
s
)
tt
(
m
i
n
)
REMARKS
1 EO1 12.51 0.22 12.0 2.73 7.16 19.5
1 EX2 36.90 0.25 15.0 9.23 6.52 60.2
1.1 12.0 11.96 7.16 85.6
3 EX3 19.80 0.25 15.0 4.95 6.52 32.3
Notes:
Street and Pipe C*A values are determined by Q/I using the catchment's intensity value.
STORM DRAINAGE SYSTEM DESIGN
STANDARD FORM SF-3
(RATIONAL METHOD PROCEDURE)
39817.00
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF
1/30/23
STREET
X:\3980000.all\3981700\Excel\Drainage\3981700 EX. Drainage_Calcs_Template_v2.07.xlsm Page 1 of 1 1/30/2024
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:ARJ
Checked By:0
Date:1/24/24
C1 0.36 100%0.22 60.8%80%0.00 0.0%90%0.00 0.0%2%0.14 0.8%61.5%
C2 0.96 100%0.65 67.5%80%0.00 0.0%90%0.02 1.8%2%0.29 0.6%70.0%
C3 2.42 100%0.01 0.4%80%2.15 71.2%90%0.00 0.0%2%0.26 0.2%71.9%
C4 1.20 100%0.00 0.0%80%1.17 78.5%90%0.00 0.0%2%0.02 0.0%78.5%
C5 1.19 100%0.00 0.0%80%1.16 78.2%90%0.00 0.0%2%0.03 0.0%78.2%
C6 1.31 100%0.00 0.0%80%1.26 77.2%90%0.00 0.0%2%0.05 0.1%77.3%
C7 0.42 100%0.00 0.00 80%0.35 67.1%90%0.00 0.0%2%0.07 0.3%67.5%
C8 1.73 100%0.00 0.00 80%1.64 75.8%90%0.00 0.0%2%0.09 0.1%75.9%
C9 0.42 100%0.15 0.37 80%0.00 0.0%90%0.00 0.0%2%0.26 1.3%38.0%
C10 2.18 100%0.04 0.02 80%0.00 0.0%90%0.00 0.0%2%2.13 2.0%4.0%
Onsite Basins 12.18 60.4%
OS1 0.43 100%0.43 1.00 100%0.00 0.0%90%0.00 0.0%2%0.00 0.0%100.0%
OS2 1.01 100%0.06 0.06 100%0.00 0.0%90%0.00 0.0%2%1.01 2.0%8.2%
OS3 37.23 100%0.04 0.00 100%0.00 0.0%90%0.00 0.0%2%37.23 2.0%2.1%
OS4 20.31 100%0.00 0.00 100%0.00 0.0%90%0.00 0.0%2%20.31 2.0%2.0%
Asphalt, Concrete
39817.00
Weighted
% Imp.
Basins Total Weighted %
Imp.Area (ac)Weighted % Imp.
Recycled Asphalt Roofs
Weighted
% Imp.
COMPOSITE % IMPERVIOUS CALCULATIONS
% Imp. Area (ac)% Imp.Area (ac)Weighted % Imp.Basin ID Total Area (ac)% Imp.Area (ac)
Lawns
% Imp.
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 2 1/30/2024
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 2 of 2 1/30/2024
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:ARJ
Checked By:0
Date:1/24/24
C1 0.36 0.80 0.00 0.00 0.00 0.95 0.22 0.58 0.72 0.20 0.14 0.08 0.10 0.66 0.82
C2 0.96 0.80 0.00 0.00 0.00 0.95 0.67 0.66 0.83 0.20 0.29 0.06 0.08 0.72 0.90
C3 2.42 0.80 2.15 0.71 0.89 0.95 0.01 0.00 0.01 0.20 0.26 0.02 0.03 0.74 0.92
C4 1.20 0.80 1.17 0.78 0.98 0.95 0.00 0.00 0.00 0.20 0.02 0.00 0.00 0.79 0.99
C5 1.19 0.80 1.16 0.78 0.98 0.95 0.00 0.00 0.00 0.20 0.03 0.00 0.01 0.79 0.98
C6 1.31 0.80 1.26 0.77 0.97 0.95 0.00 0.00 0.00 0.20 0.05 0.01 0.01 0.78 0.97
C7 0.42 0.80 0.35 0.67 0.84 0.95 0.00 0.00 0.00 0.20 0.07 0.03 0.04 0.70 0.88
C8 1.73 0.80 1.64 0.76 0.95 0.95 0.00 0.00 0.00 0.20 0.09 0.01 0.01 0.77 0.96
C9 0.42 0.80 0.00 0.00 0.00 0.95 0.15 0.35 0.44 0.10 0.26 0.06 0.08 0.41 0.52
C10 2.18 0.80 0.00 0.00 0.00 0.95 0.04 0.02 0.02 0.10 2.13 0.10 0.12 0.12 0.15
Weighted 12.18 0.63 0.76
OS1 0.43 0.80 0.00 0.00 0.00 0.95 0.43 0.95 1.00 0.15 0.00 0.00 0.00 0.95 1.00
OS2 1.01 0.80 0.00 0.00 0.00 0.95 0.06 0.06 0.07 0.15 1.01 0.15 0.19 0.21 0.26
OS3 37.23 0.80 0.00 0.00 0.00 0.95 0.04 0.00 0.00 0.15 37.23 0.15 0.19 0.15 0.19
OS4 20.31 0.80 0.00 0.00 0.00 0.95 0.00 0.00 0.00 0.15 20.31 0.15 0.19 0.15 0.19
Basins Total
Weighted 100
YEAR CRunoff Coefficient Area (ac)2 - YEAR C 100 -
YEAR C
Asphalt, Concrete, Roofs Lawns
Basins Total
Weighted 2 YEAR C
Recycled Asphalt
Total Area
(ac)
COMPOSITE RUNOFF COEFFICIENT CALCULATIONS
Basin ID Area (ac)2 - YEAR
C
100 -
YEAR C
39817.00
Runoff
Coefficient Area (ac)2 - YEAR C 100 - YEAR C Runoff Coefficient
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 2 1/30/2024
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 2 of 2 1/30/2024
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:
Calculated By:
Checked By:0
Date:1/24/24
BASIN D.A.Hydrologic Impervious C2 C100 L S o t i - 2Year t i - 100 Year L t S t K VEL.t t COMP.t c-2 Year COMP.t c 100 - Year TOTAL Tc t c-2 Year t c-100 Year
ID (ac)Soils Group (%)(ft)(%)(min)(min)(ft)(%)(ft/s)(min)(min)(min)LENGTH (ft)Check (min)(min)
C1 0.36 C 2%0.66 0.82 10 2.0%9.6 6.0 10 1.0%20.0 2.0 0.1 9.6 6.1 20.0 10.1 10.0 6.0
C2 0.96 C 2%0.72 0.90 50 2.0%18.2 9.5 481 0.6%20.0 1.5 5.4 23.6 14.9 531.0 13.0 13.0 13.0
C3 2.42 C 2%0.74 0.92 50 2.0%17.4 8.6 568 0.5%20.0 1.4 6.7 24.1 15.3 617.8 13.4 13.0 13.0
C4 1.20 C 2%0.79 0.99 50 2.0%15.0 5.5 587 0.5%20.0 1.4 6.9 21.9 12.4 637.0 13.5 14.0 12.0
C5 1.19 C 2%0.79 0.98 50 2.0%15.1 5.6 612 0.5%20.0 1.4 7.2 22.3 12.8 662.0 13.7 14.0 13.0
C6 1.31 C 2%0.78 0.97 50 2.0%15.4 6.1 653 0.5%20.0 1.4 7.7 23.1 13.8 703.0 13.9 14.0 14.0
C7 0.42 C 2%0.70 0.88 30 1.5%16.2 9.0 206 0.5%20.0 1.5 2.4 18.6 11.4 236.0 11.3 11.0 11.0
C8 1.73 C 2%0.77 0.96 50 2.0%15.9 6.7 727 0.5%20.0 1.4 8.6 24.5 15.3 776.6 14.3 14.0 14.0
C9 0.42 C 2%0.41 0.52 20 20.0%9.8 8.3 520 0.4%20.0 1.3 6.9 16.6 15.2 540.0 13.0 13.0 13.0
C10 2.18 C/B 2%0.12 0.15 20 2.0%29.9 29.0 310 0.3%21.0 1.1 4.9 34.8 33.9 330.0 11.8 12.0 12.0
OS1 0.43 C/B 2%0.95 1.00 17 1.0%5.3 3.5 376 0.5%15.0 1.1 5.9 11.2 9.4 393.0 12.2 11.0 9.0
OS2 1.01 C/B 2%0.21 0.26 100 1.0%76.2 71.7 421 1.0%15.0 1.5 4.7 80.8 76.4 520.8 12.9 13.0 13.0
OS3 37.23 C/B 2%0.15 0.19 100 1.0%81.1 77.9 1100 0.6%5.0 0.4 47.3 128.4 125.2 1200.0 16.7 17.0 17.0
OS4 20.31 C/B 2%0.15 0.19 100 1.0%81.2 78.0 1935 0.3%16.0 0.8 40.3 121.5 118.3 2035.0 21.3 21.0 21.0
Notes:
Velocity V = K*St^0.5
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN
39817.00
FINAL
Time of Concentration -Check
ARJ
(Tc)DATA
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 1/30/2024
Project Name:Front Range RV Boat and Storage
Subdivision:RV, Boat & Storage Project No.:
Location:Fort Collins Calculated By:ARJ
Design Storm:Checked By:0
Date:
TRAVEL TIME
STREET
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REMARKS
sheet drains over RIPRAP on the site
1 C1 0.36 0.66 10.0 0.24 2.21 0.5
drains into swale
2 C2 0.96 0.72 13.0 0.69 1.98 1.4
3 C3 2.42 0.74 13.0 1.78 1.98 3.5 13.0 2.02 1.98 4.0 drains into RG- Basin C1 and C3
3.1 13.0 2.71 1.98 5.4 Basins C1,C2 and C3
4 C4 1.20 0.79 14.0 0.94 1.92 1.8 drains into RG
4.1 14.0 3.65 1.92 7.0 Basins C1,C2, C3 and C4
5 C5 1.19 0.79 14.0 0.94 1.92 1.8 drains into RG
5.1 14.0 4.59 1.92 8.8 Basins C1,C2, C3, C4, and C5
6 C6 1.31 0.78 14.0 1.02 1.92 2.0 drains into RG
6.1 14.0 5.61 1.92 10.8 Basins C1,C2, C3, C4, C5, and C6
7 C7 0.42 0.70 11.0 0.29 2.13 0.6 drains into RG
7.1 14.0 5.90 1.92 11.3 Basins C1,C2, C3, C4, C5,C6 andC7
8 C8 1.73 0.77 14.0 1.33 1.92 2.6 drains into RG into pond
8.1 14.0 7.23 1.92 13.9 Basins C1,C2, C3, C4, C5,C6, C7 and C8
9 C9 0.42 0.41 13.0 0.17 1.98 0.3 14.0 7.40 1.92 14.2 Basins C1,C2, C3, C4, C5,C6, C7, C8, C9
Total Flow into pond
10 C10 2.18 0.12 12.0 0.26 2.05 0.5 14.0 7.66 1.92 14.7 Basins C1,C2, C3, C4, C5,C6, C7, C8, C9
O3 OS3 37.23 0.15 17.0 5.63 1.75 9.9 Total Flow into pond
11
Total flow out of the site
12 OS4 20.31 0.15 21.0 3.05 1.56 4.8 4.8
Flow from SWMM avg of element 299 and 99
O1 19.5 from boxelder AB swmm model
OS1 0.43 0.95 11.0 0.40 2.13 0.9
Offsite flow
O2 OS2 1.01 0.21 13.0 0.21 1.98 0.4 20.8
Notes:
Street and Pipe C*A values are determined by Q/i using the catchment's intensity value.
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
39817.00
1/24/24
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 1/30/2024
Project Name:Front Range RV Boat and Storage
Subdivision:RV, Boat & Storage Project No.:
Location:Fort Collins Calculated By:ARJ
Design Storm:Checked By:0
Date:
TRAVEL TIME
STREET
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REMARKS
sheet drains over RIPRAP on the site
1 C1 0.36 0.82 6.0 0.30 9.31 2.8
drains into swale
2 C2 0.96 0.90 13.0 0.87 6.92 6.0
3 C3 2.42 0.92 13.0 2.23 6.92 15.4 13.0 2.53 6.92 17.5 drains into RG- Basin C1 and C3
3.1 13.0 3.40 6.92 23.5 Basins C1,C2 and C3
4 C4 1.20 0.99 12.0 1.18 7.16 8.4 drains into RG
4.1 13.0 4.58 6.92 31.7 Basins C1,C2, C3 and C4
5 C5 1.19 0.98 13.0 1.17 6.92 8.1 drains into RG
5.1 13.0 5.75 6.92 39.8 Basins C1,C2, C3, C4, and C5
6 C6 1.31 0.97 14.0 1.27 6.71 8.5 drains into RG
6.1 14.0 7.02 6.71 47.1 Basins C1,C2, C3, C4, C5, and C6
7 C7 0.42 0.88 11.0 0.37 7.42 2.7 drains into RG
7.1 14.0 7.39 6.71 49.6 Basins C1,C2, C3, C4, C5,C6 andC7
8 C8 1.73 0.96 14.0 1.66 6.71 11.1 drains into RG into pond
8.1 14.0 9.05 6.71 60.7 Basins C1,C2, C3, C4, C5,C6, C7 and C8
9 C9 0.42 0.52 13.0 0.22 6.92 1.5 14.0 9.27 6.71 62.2 Basins C1,C2, C3, C4, C5,C6, C7, C8, C9
Total Flow into pond
10 C10 2.18 0.15 12.0 0.32 7.16 2.3 14.0 9.59 6.71 64.3 Basins C1,C2, C3, C4, C5,C6, C7, C8, C9
O3 OS3 37.23 0.19 17.0 7.03 6.10 42.9 Total Flow into pond
11 4.0
Total flow out of the site
12 OS4 20.31 0.19 21.0 3.81 5.46 20.8 24.8
Flow from SWMM avg of element 299 and 99
O1 229.9 from boxelder AB swmm model
OS1 0.43 1.00 9.0 0.43 8.03 3.5
Offsite flow
O2 OS2 1.01 0.26 13.0 0.26 6.92 1.8 235.2
Notes:
Street and Pipe C*A values are determined by Q/i using the catchment's intensity value.
STORM DRAINAGE SYSTEM DESIGN
STANDARD FORM SF-3
(RATIONAL METHOD PROCEDURE)
39817.00
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF
1/24/24
STREET
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 1 1/30/2024
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:39817.00
Calculated By:ARJ
Checked By:0
Date:1/24/24
O1 DESIGN POINT O2 DESIGN POINT DESIGN POINT Notes
Q100 (cfs):229.9 235.2 Flows are the greater of proposed vs.
future
Conduit Box Culvert Box Culvert
D c , Pipe Diameter (in):N/A N/A
W , Box Width (ft):10 10
H , Box Height (ft):3 3
Y t , Tailwater Depth (ft):1.20 1.20 If unknown, use Y t /D c (or H )=0.4
Y t /Dc or Y t /H 0.40 0.40
Q/D2.5 or Q/(WH3/2)4.43 4.53
Supercritical?Yes Yes
Y n , Normal Depth (ft) [Supercritical]:1.00 1.00
D a ,H a (in) [Supercritical]:2.00 2.00 D a =(D c +Y n )/2
Riprap d 50 (in) [Supercritical]:4.55 4.66
Riprap d 50 (in) [Subcritical]:N/A N/A
Required Riprap Size:L L Fig. 9-38 or Fig. 9-36
d 50 (in):9 9
Expansion Factor, 1/(2 tan):5.00 5.00 Read from Fig. 9-35 or 9-36
0.10 0.10
Erosive Soils?No No
Area of Flow,A t (ft2):32.85 33.60 A t =Q/V
Length of Protection, L p (ft):86.9 90.0 L=(1/(2 tan ))(At/Yt - D)
Min Length (ft)30.0 30.0 Min L=3D or 3H
Max Length (ft)30.0 30.0 Max L=10D or 10H
Min Bottom Width,T (ft):20.3 20.9 T=2*(Lp*tan)+W
Design Length (ft)30.0 30.0
Design Width (ft)20.3 20.9
Riprap Depth (in)18 18 Depth=2(d50)
Type II Bedding Depth (in)*6 6 *Not used if Soil Riprap
Cutoff Wall No No
Cutoff Wall Depth (ft)Depth of Riprap and Base
Cutoff Wall Width (ft)
Note: No Type II Base to be used if Soil Riprap is specified within the plans
* For use when the flow in the culvert is supercritical (and less than full).
STORM DRAIN SYSTEM
PIPE OUTFALL RIPRAP SIZING CALCULATIONS
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 2 1/30/2024
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 2 of 2 1/30/2024
Front Range Storage
Preliminary Drainage Report
13
APPENDIX C – HYDRAULIC CALCULATIONS
100 Year
This is to convert % imp. to a C value
100-year (must insert % imp. and C pervious).
ft3 acre-ft.
'C' value 0.63 (2 yr)94671.5 2.173
'C' * 1.25 0.7875 (100 yr)
Area 12.18 acres Modified Modified
Release Rate 4.5 (2- yr Historic)M. FATER D. JUDISH C. LI
May-95 Nov-97 Nov-98
DETENTION POND SIZING
TIME TIME INTENSITY Q 100 Runoff Release Required Required
cum 100 year Volume Cum total Detention Detention
(mins)(secs)(in/hr)(cfs)(ft^3)(ft^3)(ft^3)(ac-ft)
0 0 0 0.00 0 0.0 0.0 0.0000
5 300 9.950 95.44 28631.37 1350.0 27281.4 0.6263
10 600 7.720 74.05 44428.99 2700.0 41729.0 0.9580
15 900 6.520 62.54 56284.39 4050.0 52234.4 1.1991
20 1200 5.600 53.71 64456.56 5400.0 59056.6 1.3558
25 1500 4.980 47.77 71650.37 6750.0 64900.4 1.4899
30 1800 4.520 43.35 78038.48 8100.0 69938.5 1.6056
35 2100 4.080 39.13 82182.11 9450.0 72732.1 1.6697
40 2400 3.740 35.87 86095.55 10800.0 75295.5 1.7285
45 2700 3.460 33.19 89606.13 12150.0 77456.1 1.7781
50 3000 3.230 30.98 92944.06 13500.0 79444.1 1.8238
55 3300 3.030 29.06 95907.91 14850.0 81057.9 1.8608
60 3600 2.860 27.43 98756.66 16200.0 82556.7 1.8952
65 3900 2.720 26.09 101749.3 17550.0 84199.3 1.9329
70 4200 2.590 24.84 104339.1 18900.0 85439.1 1.9614
75 4500 2.480 23.79 107043.9 20250.0 86793.9 1.9925
80 4800 2.380 22.83 109576.2 21600.0 87976.2 2.0197
85 5100 2.290 21.97 112022 22950.0 89072.0 2.0448
90 5400 2.210 21.20 114467.9 24300.0 90167.9 2.0700
95 5700 2.130 20.43 116453.4 25650.0 90803.4 2.0846
100 6000 2.060 19.76 118554 27000.0 91554.0 2.1018
105 6300 2.000 19.18 120856.1 28350.0 92506.1 2.1236
110 6600 1.940 18.61 122812.8 29700.0 93112.8 2.1376
115 6900 1.890 18.13 125086 31050.0 94036.0 2.1588
120 7200 1.840 17.65 127071.5 32400.0 94671.5 2.1734
125 7500 1.790 17.17 128769.2 33750.0 95019.2 2.1813
130 7800 1.750 16.79 130927.4 35100.0 95827.4 2.1999
135 8100 1.710 16.40 132855.3 36450.0 96405.3 2.2132
140 8400 1.670 16.02 134553.1 37800.0 96753.1 2.2211
145 8700 1.630 15.63 136020.6 39150.0 96870.6 2.2238
150 9000 1.600 15.35 138121.2 40500.0 97621.2 2.2411
155 9300 1.570 15.06 140049.1 41850.0 98199.1 2.2543
160 9600 1.540 14.77 141804.4 43200.0 98604.4 2.2636
165 9900 1.510 14.48 143387.1 44550.0 98837.1 2.2690
170 10200 1.480 14.20 144797.1 45900.0 98897.1 2.2704
175 10500 1.450 13.91 146034.4 47250.0 98784.4 2.2678
180 10800 1.420 13.62 147099.1 48600.0 98499.1 2.2612
185 11100 1.400 13.43 149055.8 49950.0 99105.8 2.2752
190 11400 1.380 13.24 150897.4 51300.0 99597.4 2.2864
195 11700 1.360 13.04 152623.9 52650.0 99973.9 2.2951
200 12000 1.340 12.85 154235.3 54000.0 100235.3 2.3011
205 12300 1.320 12.66 155731.7 55350.0 100381.7 2.3044
210 12600 1.300 12.47 157112.9 56700.0 100412.9 2.3052
215 12900 1.280 12.28 158379 58050.0 100329.0 2.3032
220 13200 1.260 12.09 159530 59400.0 100130.0 2.2987
225 13500 1.240 11.89 160565.9 60750.0 99815.9 2.2915
230 13800 1.220 11.70 161486.7 62100.0 99386.7 2.2816
235 14100 1.210 11.61 163644.8 63450.0 100194.8 2.3002
240 14400 1.200 11.51 165745.4 64800.0 100945.4 2.3174
Required detention
DETENTION - FAA 100 YEAR
Page 1
Project:
Basin ID:
Depth Increment =0.50 ft
Watershed Information Top of Micropool --0.00 ------37 0.001
Selected BMP Type =EDB 4977.97 --0.50 ------4,211 0.097 1,062 0.024
Watershed Area =4.27 acres 4978.47 --1.00 ------20,556 0.472 7,253 0.167
Watershed Length =550 ft 4978.97 --1.50 ------44,063 1.012 23,408 0.537
Watershed Length to Centroid =330 ft 4979.47 --2.00 ------62,966 1.445 50,165 1.152
Watershed Slope =0.009 ft/ft 4979.97 --2.50 ------76,326 1.752 84,988 1.951
Watershed Imperviousness =25.80%percent 4980.47 --3.00 ------82,955 1.904 124,808 2.865
Percentage Hydrologic Soil Group A =0.0%percent 4980.97 --3.50 ------88,302 2.027 167,623 3.848
Percentage Hydrologic Soil Group B =0.0%percent --------
Percentage Hydrologic Soil Groups C/D =100.0%percent --------
Target WQCV Drain Time =40.0 hours --------
Location for 1-hr Rainfall Depths = User Input --------
--------
--------
Optional User Overrides --------
Water Quality Capture Volume (WQCV) =0.049 acre-feet acre-feet --------
Excess Urban Runoff Volume (EURV) =0.099 acre-feet acre-feet --------
2-yr Runoff Volume (P1 = 0.82 in.) =0.058 acre-feet 0.82 inches --------
5-yr Runoff Volume (P1 = 1.09 in.) =0.107 acre-feet inches --------
10-yr Runoff Volume (P1 = 1.4 in.) =0.198 acre-feet 1.40 inches --------
25-yr Runoff Volume (P1 = 1.69 in.) =0.318 acre-feet inches --------
50-yr Runoff Volume (P1 = 1.99 in.) =0.422 acre-feet inches --------
100-yr Runoff Volume (P1 = 2.86 in.) =0.756 acre-feet 2.86 inches --------
500-yr Runoff Volume (P1 = 3.14 in.) =0.857 acre-feet inches --------
Approximate 2-yr Detention Volume =0.058 acre-feet --------
Approximate 5-yr Detention Volume =0.106 acre-feet --------
Approximate 10-yr Detention Volume =0.137 acre-feet --------
Approximate 25-yr Detention Volume =0.165 acre-feet --------
Approximate 50-yr Detention Volume =0.181 acre-feet --------
Approximate 100-yr Detention Volume =0.290 acre-feet --------
--------
Define Zones and Basin Geometry --------
Zone 1 Volume (WQCV) =0.049 acre-feet --------
Zone 2 Volume (User Defined - Zone 1) =0.000 acre-feet --------
Zone 3 Volume (User Defined - Zones 1 & 2) =2.173 acre-feet --------
Total Detention Basin Volume =2.222 acre-feet --------
Initial Surcharge Volume (ISV) =user ft 3 --------
Initial Surcharge Depth (ISD) =user ft --------
Total Available Detention Depth (Htotal) =user ft --------
Depth of Trickle Channel (HTC) =user ft --------
Slope of Trickle Channel (STC) =user ft/ft --------
Slopes of Main Basin Sides (Smain) =user H:V --------
Basin Length-to-Width Ratio (RL/W) =user --------
--------
Initial Surcharge Area (AISV) =user ft 2 --------
Surcharge Volume Length (LISV) =user ft --------
Surcharge Volume Width (WISV) =user ft --------
Depth of Basin Floor (HFLOOR) =user ft --------
Length of Basin Floor (LFLOOR) =user ft --------
Width of Basin Floor (WFLOOR) =user ft --------
Area of Basin Floor (AFLOOR) =user ft 2 --------
Volume of Basin Floor (VFLOOR) =user ft 3 --------
Depth of Main Basin (HMAIN) =user ft --------
Length of Main Basin (LMAIN) =user ft --------
Width of Main Basin (WMAIN) =user ft --------
Area of Main Basin (AMAIN) =user ft 2 --------
Volume of Main Basin (VMAIN) =user ft 3 --------
Calculated Total Basin Volume (Vtotal) =user acre-feet --------
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DETENTION BASIN STAGE-STORAGE TABLE BUILDER
Optional
Override
Area (ft 2)
Length
(ft)
Optional
Override
Stage (ft)
Stage
(ft)
Stage - Storage
Description
Area
(ft 2)
Width
(ft)
Front Range RV Boat and Storage
Note - area was adjusted to Calc. WQCV to equal 0.049 Acre-ft - by 20%
MHFD-Detention, Version 4.06 (July 2022)
Volume
(ft 3)
Volume
(ac-ft)
Area
(acre)
After providing required inputs above including 1-hour rainfall
depths, click 'Run CUHP' to generate runoff hydrographs using
the embedded Colorado Urban Hydrograph Procedure.
ExampleZone Configuration (Retention Pond)
3981700 MHFD-Detention_v4-06 (9).xlsm, Basin 1/30/2024, 4:22 PM
1 User Defined Stage-Area Booleans for Message
1 Equal Stage-Area Inputs Watershed L:W
1 CountA Watershed Lc:L
Watershed Slope
0 Calc_S_TC Booleans for CUHP
1 CUHP Inputs Complete
H_FLOOR 1 CUHP Results Calculated
L_FLOOR_OTHER
0.00 ISV 0.00 ISV
0.00 Floor 0.00 Floor
0.66 Zone 1 (WQCV)0.66 Zone 1 (WQCV)
0.66 Zone 2 (User)0.66 Zone 1 (WQCV)
2.66 Zone 3 (User)2.66 Zone 3 (User)
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
MHFD-Detention, Version 4.06 (July 2022)
0.000
0.965
1.930
2.895
3.860
0.000
0.510
1.020
1.530
2.040
0.00 1.00 2.00 3.00 4.00
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Stage (ft.)
Area (acres)Volume (ac-ft)
0
22100
44200
66300
88400
0
5
10
15
20
0.00 1.00 2.00 3.00 4.00
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Stage (ft)
Length (ft)Width (ft)Area (sq.ft.)
3981700 MHFD-Detention_v4-06 (9).xlsm, Basin 1/30/2024, 4:22 PM
Project:
Basin ID:
Estimated Estimated
Stage (ft)Volume (ac-ft)Outlet Type
Zone 1 (WQCV)0.66 0.049 Orifice Plate
Zone 2 (User)0.66 0.000 Weir&Pipe (Restrict)
Zone 3 (User)2.66 2.173 Weir&Pipe (Restrict)
Total (all zones)2.222
User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP)Calculated Parameters for Underdrain
Underdrain Orifice Invert Depth =ft (distance below the filtration media surface)Underdrain Orifice Area =ft2
Underdrain Orifice Diameter =inches Underdrain Orifice Centroid =feet
User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP)Calculated Parameters for Plate
Centroid of Lowest Orifice =0.00 ft (relative to basin bottom at Stage = 0 ft)WQ Orifice Area per Row =3.056E-03 ft2
Depth at top of Zone using Orifice Plate =1.00 ft (relative to basin bottom at Stage = 0 ft)Elliptical Half-Width =N/A feet
Orifice Plate: Orifice Vertical Spacing =N/A inches Elliptical Slot Centroid =N/A feet
Orifice Plate: Orifice Area per Row =0.44 sq. inches (diameter = 3/4 inch)Elliptical Slot Area =N/A ft2
User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest)
Row 1 (required)Row 2 (optional)Row 3 (optional)Row 4 (optional)Row 5 (optional)Row 6 (optional)Row 7 (optional) Row 8 (optional)
Stage of Orifice Centroid (ft)0.00 0.20
Orifice Area (sq. inches)0.44 0.44
Row 9 (optional)Row 10 (optional)Row 11 (optional)Row 12 (optional)Row 13 (optional)Row 14 (optional)Row 15 (optional) Row 16 (optional)
Stage of Orifice Centroid (ft)
Orifice Area (sq. inches)
User Input: Vertical Orifice (Circular or Rectangular)Calculated Parameters for Vertical Orifice
Not Selected Not Selected Not Selected Not Selected
Invert of Vertical Orifice =0.75 N/A ft (relative to basin bottom at Stage = 0 ft)Vertical Orifice Area =0.79 N/A
Depth at top of Zone using Vertical Orifice =1.75 N/A ft (relative to basin bottom at Stage = 0 ft)Vertical Orifice Centroid =0.50 N/A
Vertical Orifice Diameter =12.00 N/A inches
User Input: Overflow Weir (Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir and No Outlet Pipe)Calculated Parameters for Overflow Weir
grate Zone 2 Weir Zone 3 Weir Zone 2 Weir Zone 3 Weir
Overflow Weir Front Edge Height, Ho =2.67 ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =2.67
Overflow Weir Front Edge Length =5.00 feet Overflow Weir Slope Length =5.00
Overflow Weir Grate Slope =0.00 H:V Grate Open Area / 100-yr Orifice Area =9.85
Horiz. Length of Weir Sides =5.00 feet Overflow Grate Open Area w/o Debris =17.40
Overflow Grate Type =Type C Grate Overflow Grate Open Area w/ Debris =17.40
Debris Clogging % =0%%
User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice)Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate
Zone 2 Restrictor Zone 3 Restrictor Zone 2 Restrictor Zone 3 Restrictor
Depth to Invert of Outlet Pipe =0.07 ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area =1.77
Outlet Pipe Diameter =18.00 inches Outlet Orifice Centroid =0.75
Restrictor Plate Height Above Pipe Invert =18.00 inches Half-Central Angle of Restrictor Plate on Pipe =3.14
User Input: Emergency Spillway (Rectangular or Trapezoidal)Calculated Parameters for Spillway
Spillway Invert Stage=ft (relative to basin bottom at Stage = 0 ft)Spillway Design Flow Depth=feet
Spillway Crest Length =feet Stage at Top of Freeboard =feet
Spillway End Slopes =H:V Basin Area at Top of Freeboard =acres
Freeboard above Max Water Surface =feet Basin Volume at Top of Freeboard =acre-ft
Max Ponding Depth of Target Storage Volume =#REF!feet Discharge at Top of Freeboard =cfs
Routed Hydrograph Results
Design Storm Return Period =WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year
One-Hour Rainfall Depth (in) =N/A N/A 0.82 1.09 1.40 1.69 1.99 2.86
CUHP Runoff Volume (acre-ft) =0.049 0.099 0.058 0.107 0.198 0.318 0.422 0.756
Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.058 0.107 0.198 0.318 0.422 0.756
CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.0 0.3 1.2 2.5 3.4 6.5
OPTIONAL Override Predevelopment Peak Q (cfs) =N/A N/A
Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.08 0.27 0.58 0.80 1.52
Peak Inflow Q (cfs) =N/A N/A 0.6 1.1 2.0 3.4 4.5 7.7
Peak Outflow Q (cfs) =0.0 0.1 0.0 0.1 0.2 0.6 0.8 1.7
Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 0.2 0.2 0.2 0.2 0.3
Structure Controlling Flow =Plate Vertical Orifice 1 Plate Vertical Orifice 1 Vertical Orifice 1 Vertical Orifice 1 Vertical Orifice 1 Vertical Orifice 1
Max Velocity through Grate 1 (fps) =N/A N/A N/A N/A N/A N/A N/A N/A
Max Velocity through Grate 2 (fps) =N/A N/A N/A N/A N/A N/A N/A N/A
Time to Drain 97% of Inflow Volume (hours) =37 56 42 59 61 60 58 53
Time to Drain 99% of Inflow Volume (hours) =40 61 45 63 68 68 67 65
Maximum Ponding Depth (ft) =0.66 0.84 0.68 0.83 1.00 1.16 1.26 1.51
Area at Maximum Ponding Depth (acres) =0.22 0.35 0.22 0.34 0.47 0.63 0.74 1.02
Maximum Volume Stored (acre-ft) =0.049 0.101 0.052 0.097 0.167 0.249 0.318 0.548
DETENTION BASIN OUTLET STRUCTURE DESIGN
MHFD-Detention, Version 4.06 (July 2022)
Front Range RV Boat and Storage
Note - area was adjusted to Calc. WQCV to equal 0.049 Acre-ft - by 20%
The user can override the default CUHP hydrographs and runoff volumes by entering new values in the Inflow Hydrographs table (Columns W through AF).
Example Zone Configuration (Retention Pond)
3981700 MHFD-Detention_v4-06 (9).xlsm, Outlet Structure 1/30/2024, 4:22 PM
COUNTA for Basin Tab =1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2
Count_Underdrain =0 0.11(diameter = 3/8 inch)2 2 1
Count_WQPlate =1 0.14(diameter = 7/16 inch)
Count_VertOrifice1 =1 0.18(diameter = 1/2 inch)Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean
Count_VertOrifice2 =0 0.24(diameter = 9/16 inch)4 4 5yr, <72hr 0
Count_Weir1 =1 0.29(diameter = 5/8 inch)>5yr, <120hr 0
Count_Weir2 =0 0.36(diameter = 11/16 inch)Max Depth Row
Count_OutletPipe1 =1 0.42(diameter = 3/4 inch)WQCV 67
Count_OutletPipe2 =0 0.50(diameter = 13/16 inch)2 Year 69
COUNTA_2 (Standard FSD Setup)=1 0.58(diameter = 7/8 inch)EURV 85
Hidden Parameters & Calculations 0.67(diameter = 15/16 inch)5 Year 84
MaxPondDepth_Error?FALSE 0.76 (diameter = 1 inch)10 Year 101 Spillway Depth
Cd_Broad-Crested Weir 3.00 0.86(diameter = 1-1/16 inches)25 Year 117
WQ Plate Flow at 100yr depth =0.03 0.97(diameter = 1-1/8 inches)50 Year 127
CLOG #1=100%1.08(diameter = 1-3/16 inches)100 Year 152 1 Z1_Boolean
n*Cdw #1 =0.60 1.20(diameter = 1-1/4 inches)500 Year 159 1 Z2_Boolean
n*Cdo #1 =0.74 1.32(diameter = 1-5/16 inches)Zone3_Pulldown Message 0 Z3_Boolean
Overflow Weir #1 Angle =0.000 1.45(diameter = 1-3/8 inches)1 Opening Message
CLOG #2=100%1.59(diameter = 1-7/16 inches)Draintime Running
n*Cdw #2 =0.00 1.73(diameter = 1-1/2 inches)Outlet Boolean Outlet Rank Total (1 to 4)
n*Cdo #2 =0.00 1.88(diameter = 1-9/16 inches)Vertical Orifice 1 1 1 2
Overflow Weir #2 Angle =0.000 2.03(diameter = 1-5/8 inches)Vertical Orifice 2 0 0 Boolean
Underdrain Q at 100yr depth =0.00 2.20(diameter = 1-11/16 inches)Overflow Weir 1 1 2 0 Max Depth
VertOrifice1 Q at 100yr depth =1.63 2.36(diameter = 1-3/4 inches)Overflow Weir 2 0 0 0 500yr Depth
VertOrifice2 Q at 100yr depth =0.00 2.54(diameter = 1-13/16 inches)Outlet Pipe 1 1 2 0 Freeboard
2.72(diameter = 1-7/8 inches)Outlet Pipe 2 0 0 0 Spillway
Count_User_Hydrographs 0 2.90(diameter = 1-15/16 inches)0 Spillway Length
CountA_3 (EURV & 100yr) =1 3.09(diameter = 2 inches)FALSE Time Interval
CountA_4 (100yr Only) =1 3.29(use rectangular openings)Button Visibility Boolean
COUNTA_5 (FSD Weir Only)=0 0 WQCV Underdrain
COUNTA_6 (EURV Weir Only)=1 1 WQCV Plate
0 EURV-WQCV Plate
Outlet1_Pulldown_Boolean 0 EURV-WQCV VertOriice
Outlet2_Pulldown_Boolean 0 Outlet 90% Qpeak
Outlet3_Pulldown_Boolean 0 Outlet Undetained
0 Weir Only 90% Qpeak
0 Five Year Ratio Plate
0 Five Year Ratio VertOrifice
EURV_draintime_user
Spillway Options
Offset
Overlapping
Vertical Orifice 1
S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axis
minimum bound 0.00 0 0
maximum bound 2.00 50,000 10
S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis
minimum bound
maximum bound
DETENTION BASIN OUTLET STRUCTURE DESIGN
MHFD-Detention, Version 4.06 (July 2022)
0
1
2
3
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8
9
10
0.1 1 10
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500YR IN
500YR OUT
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
EURV IN
EURV OUT
WQCV IN
WQCV OUT
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DRAIN TIME [hr]
500YR
100YR
50YR
25YR
10YR
5YR
2YR
EURV
WQCV
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10,000
15,000
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0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
OU
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PONDING DEPTH [ft]
User Area [ft^2]
Interpolated Area [ft^2]
Summary Area [ft^2]
Volume [ft^3]
Summary Volume [ft^3]
Outflow [cfs]
Summary Outflow [cfs]
3981700 MHFD-Detention_v4-06 (9).xlsm, Outlet Structure 1/30/2024, 4:22 PM
Summary Stage-Area-Volume-Discharge Relationships
The user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically.
The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points.
Stage Area Area Volume Volume Total
Outflow
[ft][ft 2][acres][ft 3][ac-ft][cfs]
0.00 37 0.001 0 0.000 0.00
0.50 4,211 0.097 1,062 0.024 0.02
0.69 10,422 0.239 2,452 0.056 0.02
1.00 20,556 0.472 7,253 0.167 0.25
1.50 44,063 1.012 23,408 0.537 1.62
2.00 62,966 1.445 50,165 1.152 3.32
2.50 76,326 1.752 84,988 1.951 4.27
2.68 78,712 1.807 98,942 2.271 4.63
2.75 79,641 1.828 104,484 2.399 6.14
3.00 82,955 1.904 124,808 2.865 12.96
3.25 85,628 1.966 145,881 3.349 13.64
3.30 86,163 1.978 150,176 3.448 13.77
3.40 87,232 2.003 158,846 3.647 14.03
3.50 88,302 2.027 167,623 3.848 14.29
DETENTION BASIN OUTLET STRUCTURE DESIGN
Stage - Storage
Description
MHFD-Detention, Version 4.06 (July 2022)
For best results, include the
stages of all grade slope
changes (e.g. ISV and Floor)
from the S-A-V table on
Sheet 'Basin'.
Also include the inverts of all
outlets (e.g. vertical orifice,
overflow grate, and spillway,
where applicable).
Invert - 4977.47
WQ Volume -4978.16
Outlet Structure Overflow Weir - 4980.16
3981700 MHFD-Detention_v4-06 (9).xlsm, Outlet Structure 1/30/2024, 4:22 PM
HY-8 Culvert Analysis Report
Crossing Discharge Data
Discharge Selection Method: Specify Minimum, Design, and Maximum Flow
Minimum Flow: 0 cfs
Design Flow: 229.9 cfs
Maximum Flow: 240 cfs
Table 1 - Summary of Culvert Flows at Crossing: 12'X2' BOX CULVERT
Headwater Elevation
(ft)Total Discharge (cfs)Culvert 1 Discharge
(cfs)
Roadway Discharge
(cfs)Iterations
4981.50 0.00 0.00 0.00 1
4982.46 24.00 24.00 0.00 1
4983.03 48.00 48.00 0.00 1
4983.49 72.00 72.00 0.00 1
4983.90 96.00 96.00 0.00 1
4984.28 120.00 120.00 0.00 1
4984.66 144.00 144.00 0.00 1
4985.06 168.00 168.00 0.00 1
4985.47 192.00 192.00 0.00 1
4986.20 229.90 229.90 0.00 1
4986.41 240.00 240.00 0.00 1
4986.53 245.47 245.47 0.00 Overtopping
Rating Curve Plot for Crossing: 12'X2' BOX CULVERT
Table 2 - Culvert Summary Table: Culvert 1
********************************************************************************
Straight Culvert
Inlet Elevation (invert): 4981.50 ft, Outlet Elevation (invert): 4981.24 ft
Culvert Length: 85.00 ft, Culvert Slope: 0.0031
********************************************************************************
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth (ft)
Outlet
Control
Depth (ft)
Flow
Type
Normal
Depth (ft)
Critical
Depth (ft)
Outlet
Depth (ft)
Tailwater
Depth (ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
0.00 0.00 4981.50 0.000 0.000 0-NF 0.000 0.000 0.000 0.000 0.000 0.000
24.00 24.00 4982.46 0.965 0.413 1-S2n 0.555 0.563 0.555 0.655 4.326 2.155
48.00 48.00 4983.03 1.531 0.819 1-S2n 0.860 0.894 0.860 1.008 5.584 2.801
72.00 72.00 4983.49 1.989 1.202 1-S2n 1.115 1.172 1.115 1.301 6.456 3.254
96.00 96.00 4983.90 2.399 1.588 1-S2n 1.345 1.420 1.345 1.563 7.137 3.613
120.00 120.00 4984.28 2.785 1.989 1-S2n 1.559 1.648 1.559 1.804 7.700 3.913
144.00 144.00 4984.66 3.164 2.412 5-S2n 1.760 1.860 1.760 2.030 8.182 4.173
168.00 168.00 4985.06 3.555 2.858 5-S2n 1.952 2.062 1.952 2.245 8.606 4.402
192.00 192.00 4985.47 3.970 3.331 5-S2n 2.137 2.254 2.137 2.451 8.983 4.609
229.90 229.90 4986.20 4.698 4.136 5-S2n 2.419 2.541 2.419 2.761 9.506 4.898
240.00 240.00 4986.41 4.911 4.363 5-S2n 2.491 2.615 2.491 2.841 9.633 4.969
Culvert Performance Curve Plot: Culvert 1
Water Surface Profile Plot for Culvert: Culvert 1
Site Data - Culvert 1
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 4981.50 ft
Outlet Station: 85.00 ft
Outlet Elevation: 4981.24 ft
Number of Barrels: 1
Culvert Data Summary - Culvert 1
Barrel Shape: Concrete Box
Barrel Span: 10.00 ft
Barrel Rise: 3.00 ft
Barrel Material: Concrete
Embedment: 0.00 in
Barrel Manning's n: 0.0120
Culvert Type: Straight
Inlet Configuration: Square Edge (90º) Headwall
Inlet Depression: None
Table 3 - Downstream Channel Rating Curve (Crossing: 12'X2' BOX CULVERT)
Tailwater Channel Data - 12'X2' BOX CULVERT
Tailwater Channel Option: Rectangular Channel
Bottom Width: 17.00 ft
Channel Slope: 0.0050
Channel Manning's n: 0.0350
Channel Invert Elevation: 4981.24 ft
Roadway Data for Crossing: 12'X2' BOX CULVERT
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 181.00 ft
Crest Elevation: 4986.53 ft
Roadway Surface: Paved
Roadway Top Width: 71.00 ft
Flow (cfs)Water Surface
Elev (ft)Depth (ft)Velocity (ft/s)Shear (psf)Froude Number
0.00 4981.24 0.00 0.00 0.00 0.00
24.00 4981.90 0.66 2.16 0.20 0.47
48.00 4982.25 1.01 2.80 0.31 0.49
72.00 4982.54 1.30 3.25 0.41 0.50
96.00 4982.80 1.56 3.61 0.49 0.51
120.00 4983.04 1.80 3.91 0.56 0.51
144.00 4983.27 2.03 4.17 0.63 0.52
168.00 4983.48 2.24 4.40 0.70 0.52
192.00 4983.69 2.45 4.61 0.76 0.52
229.90 4984.00 2.76 4.90 0.86 0.52
240.00 4984.08 2.84 4.97 0.89 0.52
Crossing Discharge Data
Discharge Selection Method: Specify Minimum, Design, and Maximum Flow
Minimum Flow: 0 cfs
Design Flow: 235.2 cfs
Maximum Flow: 240 cfs
Table 4 - Summary of Culvert Flows at Crossing: 10'X3' BOX CULVERT
Headwater Elevation
(ft)Total Discharge (cfs)Culvert 2 Discharge
(cfs)
Roadway Discharge
(cfs)Iterations
4976.71 0.00 0.00 0.00 1
4977.75 24.00 24.00 0.00 1
4978.37 48.00 48.00 0.00 1
4978.90 72.00 72.00 0.00 1
4979.38 96.00 96.00 0.00 1
4979.83 120.00 120.00 0.00 1
4980.19 144.00 144.00 0.00 1
4980.78 168.00 168.00 0.00 1
4981.41 192.00 192.00 0.00 1
4982.60 235.20 235.20 0.00 1
4982.74 240.00 240.00 0.00 1
4983.06 251.07 251.07 0.00 Overtopping
Rating Curve Plot for Crossing: 10'X3' BOX CULVERT
Table 5 - Culvert Summary Table: Culvert 2
********************************************************************************
Straight Culvert
Inlet Elevation (invert): 4976.71 ft, Outlet Elevation (invert): 4976.43 ft
Culvert Length: 92.00 ft, Culvert Slope: 0.0030
********************************************************************************
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth (ft)
Outlet
Control
Depth (ft)
Flow
Type
Normal
Depth (ft)
Critical
Depth (ft)
Outlet
Depth (ft)
Tailwater
Depth (ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
0.00 0.00 4976.71 0.000 0.000 0-NF 0.000 0.000 0.000 0.000 0.000 0.000
24.00 24.00 4977.75 0.965 1.042 1-S1t 0.556 0.563 0.936 0.936 2.563 2.563
48.00 48.00 4978.37 1.531 1.662 1-S1t 0.861 0.894 1.469 1.469 3.267 3.267
72.00 72.00 4978.90 1.989 2.191 1-S1t 1.117 1.172 1.925 1.925 3.739 3.739
96.00 96.00 4979.38 2.399 2.670 1-S1t 1.347 1.420 2.342 2.342 4.098 4.098
120.00 120.00 4979.83 2.785 3.118 1-S1t 1.561 1.648 2.734 2.734 4.389 4.389
144.00 144.00 4980.19 3.164 3.479 4-FFf 1.763 1.860 3.000 3.108 4.800 4.632
168.00 168.00 4980.78 3.555 4.075 4-FFf 1.956 2.062 3.000 3.470 5.600 4.842
192.00 192.00 4981.41 3.970 4.697 4-FFf 2.141 2.254 3.000 3.821 6.400 5.025
235.20 235.20 4982.60 4.809 5.887 4-FFf 2.461 2.580 3.000 4.433 7.840 5.306
240.00 240.00 4982.74 4.911 6.026 4-FFf 2.496 2.615 3.000 4.499 8.000 5.334
Culvert Performance Curve Plot: Culvert 2
Water Surface Profile Plot for Culvert: Culvert 2
Site Data - Culvert 2
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 4976.71 ft
Outlet Station: 92.00 ft
Outlet Elevation: 4976.43 ft
Number of Barrels: 1
Culvert Data Summary - Culvert 2
Barrel Shape: Concrete Box
Barrel Span: 10.00 ft
Barrel Rise: 3.00 ft
Barrel Material: Concrete
Embedment: 0.00 in
Barrel Manning's n: 0.0120
Culvert Type: Straight
Inlet Configuration: Square Edge (90º) Headwall
Inlet Depression: None
Table 6 - Downstream Channel Rating Curve (Crossing: 10'X3' BOX CULVERT)
Tailwater Channel Data - 10'X3' BOX CULVERT
Tailwater Channel Option: Rectangular Channel
Bottom Width: 10.00 ft
Channel Slope: 0.0050
Channel Manning's n: 0.0350
Channel Invert Elevation: 4976.43 ft
Roadway Data for Crossing: 10'X3' BOX CULVERT
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 69.00 ft
Crest Elevation: 4983.06 ft
Roadway Surface: Paved
Roadway Top Width: 71.00 ft
Flow (cfs)Water Surface
Elev (ft)Depth (ft)Velocity (ft/s)Shear (psf)Froude Number
0.00 4976.43 0.00 0.00 0.00 0.00
24.00 4977.37 0.94 2.56 0.29 0.47
48.00 4977.90 1.47 3.27 0.46 0.48
72.00 4978.36 1.93 3.74 0.60 0.47
96.00 4978.77 2.34 4.10 0.73 0.47
120.00 4979.16 2.73 4.39 0.85 0.47
144.00 4979.54 3.11 4.63 0.97 0.46
168.00 4979.90 3.47 4.84 1.08 0.46
192.00 4980.25 3.82 5.03 1.19 0.45
235.20 4980.86 4.43 5.31 1.38 0.44
240.00 4980.93 4.50 5.33 1.40 0.44
Label Solve For Friction Method Roughness CoefficientChannel Slope (ft/ft)Water Surface Elevation (ft)Elevation Range Discharge (cfs)Flow Area (ft²)Wetted Perimeter (ft)Hydraulic Radius (in)Top Width (ft)Normal Depth (in)Critical Depth (in)Critical Slope (ft/ft)Velocity (ft/s)Velocity Head (ft)Specific Energy (ft)Froude Number Flow Type Notes Messages
100 YR Section - AA 0.019 0.004 4,981.11 4,980.1 to 4,981.8 ft 23.5 6.7 11.4 7.1 11.19 12.6 11.3 0.007 3.49 0.19 1.24 0.793 Subcritical
100 YR - Section - BB 0.019 0.004 4,980.15 4,978.6 to 4,981.5 ft 61.3 13.4 14.8 10.8 14.42 19.1 17.6 0.006 4.58 0.33 1.92 0.837 Subcritical
100 YR Section - CC 0.019 0.003 4,974.06 4,973.0 to 4,985.7 ft 25.4 8.6 12.9 8 12.61 12.8 10.2 0.007 2.96 0.14 1.2 0.633 Subcritical
100 YR Section - DD 0.02 0.01 4,981.53 4,979.7 to 4,985.6 ft 235.2 32.3 33.3 11.6 33.09 21.7 24.2 0.006 7.28 0.82 2.63 1.299 Supercritical
Front Range Storage
Preliminary Drainage Report
14
APPENDIX D – WATER QUALITY CALCULATIONS
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:39817.00
Calculated By:ARJ
Checked By:0
Date:1/24/24
Basin
Area
(ac)% Imp.
C2 0.96 70.0%
C9 0.42 38.0%
C10 2.18 4.0%
Total 3.56 25.8%
WQCV Drain Time (hr):40
Coefficient, a (Figure 3.2):1.0
WQCV (in):0.14
WQCV (ac-ft):0.049
WQCV (cu-ft):2,134.7
WQ Tributary Areas
WQCV - POND
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 1 of 3 1/30/2024
Subdivision:RV, Boat & Storage Project Name:Front Range RV Boat and Storage
Location:Fort Collins Project No.:39817.00
Calculated By:ARJ
Checked By:0
Date:1/24/24
Basin
Area
(ac)% Imp.
C1 0.36 61.5%
C3 2.42 71.9%
C4 1.20 78.5%
C5 1.19 78.2%
C6 1.31 77.3%
C7 0.42 67.5%
C8 1.73 75.9%
Total 8.62 74.70%
WQCV Drain Time (hr):12 C1, AND C3-C8
Coefficient, a (Figure 3.2):0.8
WQCV (in):0.24
WQCV (ac-ft):0.205
WQCV (cu-ft):8,950.0
WQ Tributary Areas
WQCV - RAIN GARDEN
X:\3980000.all\3981700\Excel\Drainage\39817.00 Drainage_Calcs_v2.07.xlsm Page 2 of 3 1/30/2024
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =74.7 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.747
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.24 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area)Area = 375,487 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region,VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =8,950 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical)Z =4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =5610 sq ft
D) Actual Flat Surface Area AActual =7028 sq ft
E) Area at Design Depth (Top Surface Area)ATop =11134 sq ft
F) Rain Garden Total Volume VT=9,081 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
ARJ
JR ENGINEERING, LLC
January 31, 2024
FRONT RANGE RV BOAT & STORAGE
C1 AND C3 THROUGH C7
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
C1 AND C3-C7 RAIN GARDEN UD-BMP_v3.07.xlsm, RG 1/31/2024, 8:46 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
ARJ
JR ENGINEERING, LLC
January 31, 2024
FRONT RANGE RV BOAT & STORAGE
C1 AND C3 THROUGH C7
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
C1 AND C3-C7 RAIN GARDEN UD-BMP_v3.07.xlsm, RG 1/31/2024, 8:46 AM
Front Range Storage
Preliminary Drainage Report
15
APPENDIX E – REFERENCES
Model Scenario:
Duplicate Effective = ICON conversion of
Effective MODSWMM model to EPA SWMM +
Recent Development Updates
Existing = DE + Recent
Hydrology LOMRs
SWMM Element
ICON 2014 Model - Duplicate Effective SWMM
(v 5.0.022 - from Report)
Existing Conditions SWMM
v5.1.012 As-Built v5.1.006
As-Built v5.1.011
(w/ pond problem)
As-Built v5.1.012
(w/ pond problem)
As-Built v5.1.012
(Raised Ponds)
As-Built v5.1.012
(Final)
Difference:
Exist. Cond. (v5.1.012) -
Dup. Eff. Model (ICON)
Difference:
v.011 - v.006
Difference:
v.012 - v.011
Difference:
v.012 Raised Ponds -
v.006
Difference:
v.012 Final - v.006
Model Notes:Eff. Model Conversion/ Update Corrected 'Warning 10' problem by
rasing invert elevation of 16 ponds.
Updated with corrected ponds
(raised inverts) and updated
Larimer-Weld Canal model run
Should be very close to
v5.1.006
Update to LW Canal model (unsteady
HECRAS) caused flow changes. Report
Table 5.7 shows these flow are now close
again to the CLOMR flows.
913 539.5 540.4 47.97 48.0 48.0 48.0 48.0 0.8 0.00 0.00 0.00 0.00
914 3079.6 3090.4 274.21 274.2 274.2 274.2 274.2 10.8 0.00 0.00 0.00 0.00
Node Discharge - 100yr (cfs)Comparison
As-Built
These are the same model input file, run in 3 SWMM versions These are the same model input file, run
in 3 SWMM versions - note differences
beteween v..006 and v.011
TI
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COUNTY RD 52
MULBERRY ST
MOUNTAIN VISTA DR
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E. VINE DR
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COUNTY RD 50
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195
2800
3230
3699
4950
6075
6152
6194
6215
6275
8210
9025
9713
10230
10600
11615
11635
11663
11672
11681
11723
11756
11945
11897
11892
11875
11832
11790
13050
13415
13643
14297
14550
15360
15974
16550
17225
17318
17341
17425
17985
19405
20080
20330
20670
20705
20801
20950
21990
23680
25281
*
*
*LOCATION OF CONSTRUCTED SIDE SPILL WEIR
0 2000'4000'
SCALE: 1" = 2000'
1000'
FIGURE 5.1
LARIMER & WELD
CANAL
100-YR SPILLS
LEGEND:
CROSS SECTION
LOCATION SECTION ID
(STATION)
APPROXIMATE SPILL LIMITS
Dr
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SPILL LIMITS ID
25281
Spill
Location
Existing
Condition
Flows
(Pre-Project)
As-built Flows
(Post-Project)Difference
cfs cfs cfs
A 509 166 -344
B 452 105 -347
C 2555 2513 -42
D 2147 2 -2145
E 34 0 -34
F 1731 740 -991
G 65 37 -28
H 108 108 0
TH-12
TH-2
TH-1
TH-4
TH-13
TH-5
TH-3
TH-14
TH-6
TH-15
TH-7
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Site
NE FRONTAGE RDLEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORINGS PERFORMED FOR NEWT
3 PIPELINE PROJECT (FC10581)
TH-1
TH-12
ERIC KELLEY C/O JR ENGINEERING LLC
MOUNTAIN VISTA PROPERTY
CTL I T PROJECT NO. FC10813-115
FIGURE 1
Locations of
Exploratory Borings
VICINITY MAP
(FORT COLLINS, COLORADO)
NOT TO SCALE
550'275'
APPROXIMATE
SCALE: 1" = 550'
0'
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
6/12
14/12
9/12
11/12
50/10
WC=11.2
DD=109
SW=0.0
SS=0.370
WC=4.7
DD=116
-200=23
WC=8.7
DD=114
SW=-0.1
TH-1
10/12
15/12
WC=19.9
DD=104
SW=0.9
SS=1.300
TH-2
7/12
9/12
9/12
17/12
37/12
WC=10.1
DD=114
-200=45
WC=10.8
DD=116
SW=0.0
TH-3
9/12
26/12
WC=23.2
DD=106
SW=0.4
TH-4
21/12
10/12
29/12
8/12
WC=5.6
DD=114
SW=0.0
SS=0.800
TH-5
7/12
4/12
50/5
WC=25.6
DD=96
-200=83
WC=17.2
DD=111
SW=-0.1
TH-6
7/12
2/12
4/12
WC=17.6
DD=107
SW=0.3
SS=0.040
TH-7
DE
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DE
P
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Summary Logs of
Exploratory Borings
FIGURE 2
ERIC KELLEY C/O JR ENGINEERING LLC
MOUNTAIN VISTA PROPERTY
CTL | T PROJECT NO. FC10813-115
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
8/12
42/12
40/12
26/12
WC=0.0DD=102SW=1.3SS=1.600
WC=5.1-200=7
WC=0.0DD=102SW=1.3SS=1.600
WC=5.1-200=7
TH-12
11/12
14/12
12/12
9/12
WC=10.3-200=16WC=10.3-200=16
TH-13
14/12
6/12
15/12
31/12
WC=0.0DD=113SW=0.0SS=0.490
WC=0.0DD=113SW=0.0SS=0.490
TH-14
11/12
5/12
7/12
7/12
WC=30.8DD=91WC=30.8DD=91
TH-15
DRIVE SAMPLE. THE SYMBOL 8/12 INDICATES 8 BLOWS OF A 140-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES.
SAND, CLAYEY, SILTY, SLIGHTLY MOIST TO MOIST, LOOSE TO MEDIUM DENSE, BROWN,
TAN, RUST (SC)
1.
4.
LEGEND:
CLAY, SANDY, MOIST, STIFF, BROWN (CL)
DE
P
T
H
-
F
E
E
T
THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN
THIS REPORT.
NOTES:
WATER LEVEL MEASURED MAY 1, 2023
GRAVEL, SANDY, SLIGHTLY MOIST TO WET,MEDIUM DENSE TO VERY DENSE, REDDISH
BROWN (GP)
INDICATES DEPTH WHERE HOLE CAVED PRIOR TO SECONDARY
GROUNDWATER MEASUREMENTS.
INDICATES MOISTURE CONTENT (%).
INDICATES DRY DENSITY (PCF).
INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%).
INDICATES PASSING NO. 200 SIEVE (%).
INDICATES LIQUID LIMIT.
INDICATES PLASTICITY INDEX.
INDICATES UNCONFINED COMPRESSIVE STRENGTH (PSF).
INDICATES SOLUBLE SULFATE CONTENT (%).
3.
DE
P
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F
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WATER LEVEL MEASURED AT TIME OF DRILLING.
Summary Logs of
Exploratory Borings
BORINGS 1-7 WERE DRILLED ON APRIL 21ST, 2023 USING 4-INCH DIAMETER
CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG.
FIGURE 3
WC
DD
SW
-200
LL
PI
UC
SS
-
-
-
-
-
-
-
-
ERIC KELLEY C/O JR ENGINEERING LLC
MOUNTAIN VISTA PROPERTY
CTL | T PROJECT NO. FC10813-115
BORINGS 12-15 WERE PERFORMED ON NOVEMBER 8TH, 2022 AS A PART OF THE NEWT 3
PIPELINE PROJECT (FC10581)
2.
Front Range Storage
Preliminary Drainage Report
16
APPENDIX F – MAPS
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LEGEND
Know what's below.
before you dig.Call
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before you dig.Call
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before you dig.Call
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C
A Westrian Company
FRONT RANGE RV BOAT AND STORAGE
BOX ELDER CREEK - ASBUILT MODEL
SWMM EXHIBIT
Front Range Storage
Preliminary Drainage Report
17
APPENDIX G –LID EXHIBIT
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Know what's below.
before you dig.Call
R
LID TREATMENT
A
A
B
B
D D
KELLEY STREET