HomeMy WebLinkAboutDrainage Reports - 11/06/2023City of Fort Collins Approved Plans
Approved by: sagenbroad
Date: 11/06/2023
FINAL DRAINAGE REPORT
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Heartside Hill
Prepared by:
Highland Development Services
6355 Fairgrounds Ave, Suite 100
Windsor, Colorado 80550
Phone: 970.674.7550
Prepared for:
CARE Housing, Inc.
1303 W. Swallow Road
Fort Collins, CO 80525
Office: 970.282.7522
August 28, 2023
Job Number 21-1045-00
3
HIGHLAND
��VELOPMENT SERVICES
August 28, 2023
Mr. Basil Hamdan, P.E.
Fort Collins Utilities — Stormwater Department
700 Wood Street
Fort Collins, CO 80522
RE: Final Drainage Report for Heartside Hill
Fort Collins Stormwater Department,
,�
HIGHLAND
_ �_ - � ��
We are pleased to submit for your review, the Final Drainage Report for the Heartside Hill
affordable residential housing project. This report describes the drainage design in accordance
with the City of Fort Collins Stormwater Criteria Manual.
We appreciate your time and consideration in reviewing this submittal. Please call if you have
any questions.
Sincerely,
Highland DQvelo me�t Services
Jas T. Claey ,.E., LEED AP
%� �%
Highland Development Services, Inc.
6355 Fairgrounds Avenue, Suite 100 � Windsor, CO 80550 � 970.674.7550
TABLE OF CONTENTS
Tableof Contents ............................................................................................................................. i
EngineerCertification ......................................................................................................................ii
GeneralDescription and Location .................................................................................................. 1
SiteDescription and Location ...................................................................................................... 1
SiteSoils ....................................................................................................................................... 1
StormDrainage Criteria .................................................................................................................. 3
HydrologicCriteria ....................................................................................................................... 3
HydraulicCriteria ......................................................................................................................... 3
DrainageBasins ............................................................................................................................... 4
DrainageFacility Design .................................................................................................................. 5
DrainageConveyance Design ...................................................................................................... 5
Detention/Water Quality Pond Design ....................................................................................... 5
LowImpact Development ............................................................................................................... 6
Stormwater Pollution Prevention ................................................................................................... 8
Conclusions..................................................................................................................................... 9
References.................................................................................................................................... 10
Appendix....................................................................................................................................... 11
Appendix A— Site Descriptions, Characteristics, & References .................................................. A
Appendix B— Rational Calculations ............................................................................................. B
Appendix C— Pond Calculations .................................................................................................. C
Appendix D— Low Impact Development Calculations ................................................................ D
Appendix E— Inlet, Pipe, & Swale Capacity Calculations ............................................................ E
Page i
ENGINEER CERTIFICATION
I hereby certify that this report (plan) for the final drainage design of Heartside Hill was
prepared by me (or under my direct supervision) in accordance with the provisions of the City
of Fort Collins Stormwater Criteria Manual and Construction of Public and Private
Improvements for the Responsible Parties thereof. I understand that the City of Fort Collins
does not and shall not as ''ty for drainage facilities designed by others.
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Jason T. Claeys, PE vJ��NAL
Registered Professional Engineei
State of Colorado No. 42122
Page ii
GENERAL DESCRIPTION AND LOCATION
SITE DESCRIPTION AND LOCATION
The project site is situated in the southeast quarter of Section 12, Township 6 North, Range 69
West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, in the State of
Colorado. The property consists of Lots 1 and 2, Block 1 of the Heart of the Rockies Second
Subdivision, dated June 9, 1999. Heartside Hill is located within Lot 2, at the northwest corner
of the intersection of S. Lemay Ave. and E. Trilby Rd. Lot 1 contains the existing Heart of the
Rockies Christian Church. It is bounded by private residential lots to the north and west, E.
Trilby Rd. to the south, and S Lemay Ave to the east.
The existing church facilities are anticipated to remain. The site area is currently undeveloped
and is approximately 8.84 acres. The development would consist of up to 72 CARE Housing for
rent apartment units ([6] 12-unit buildings), 9 Habitat for Humanity (H4H) single-family
detached lots, 2 L'arche group homes, and a planned shared community center to be designed
and constructed at a future date. The project is anticipated to be completed in a single phase.
The project site generally slopes from the southwest to the northeast at approximately 4%
toward an existing pond at the northeast of the property. Storm runoff is currently conveyed
from a grate inlet in the pond to a ditch along the east side of the property and into the existing
storm drain sewer. The existing project site is approximately 0.0% impervious. No wetlands are
located within the area of proposed development.
The project site is not located within the FEMA floodway or floodplain and is within the non-
printed FEMA FIRM panel 08069C1200F, effective 12/19/2006. The site is also not located
within the City of Fort Collins floodplain.
The proposed development includes six multi-family buildings with a clubhouse along with
eleven low-income housing lots. The required parking areas, driveways, sidewalks, and open
space are also included in the development. A rain garden is proposed to provide the
stormwater quality enhancement requirement as a low impact development technique.
The site was previously analyzed within the "Drainage Investigation for Heart of the Rockies
Christian Church," prepared by Messner Engineering, Inc., dated June 29, 1999.
SITE SOILS
The Heatside Hill project site consists primarily of Renohill clay loam and a small portion of
Longmont clay and are both classified as Type D hydrologic group. According to USDA/Natural
Page 1
Resource Conservation Group, Type D soils a have very slow infiltration rate when thoroughly
wet. These soils 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 also have a very slow rate of water
transmission.
Per the "Preliminary Geotechnical Subsurface Exploration Report, Proposed Residential
Development Lots 1 and 2, Heart of the Rockies Second Subdivision", prepared by Soilogic, Inc.
dated August 13, 2021:
"The subsurface materials encountered in the completed site borings were quite variable across
the site, but generally consisted of a thin mantle of vegetation and topsoil underlain by
brown/beige/rust lean clay with varying amounts of sand. A portion of the near-surface lean
clay encountered at the location of boring 8-2 extending to a depth of about 3 to 4 feet below
ground surface was somewhat mottled in color, appeared to contain bedrock fragments and
was identified as possible existing fill material which may have been placed to develop present
site grade. In general, the lean clay varied from medium stiff to very stiff in terms of consistency,
exhibited variable swell potential (ranging from none to very high) at current moisture and
density conditions and extended to depths between 2% to 18 feet below present site grade,
where it was underlain by brown/olive/beige/gray/rust interbedded claystone/siltstone/
sandstone bedrock of varying composition. The bedrock varied from weathered to very hard in
terms of hardness, also exhibited variable swell potential (ranging from low to high) at in-situ
moisture and density conditions and extended to the bottom of each boring at depths ranging
from approximately 15 to 30 feet below present site grades. In general, we judge the bedrock
unit underlying the site to possess moderate to high swell potential overall."
Groundwater was also observed during the subsurface soil exploration:
"Groundwater was measured in borings 8-1, 8-2, 8-3 and 8-6 at depths between about 13 and
27 feet below ground surface, but was not encountered in any of the remaining site borings to
the depths explored when checked immediately after completion of drilling. When checked
seven (7J days after drilling, groundwater was measured in all borings with the exception of
boring 8-3 at depths between about 5 and 15 feet below ground surface. The ground surface in
the area of boring e-3 had been disturbed, such that subsequent groundwater level
measurements could not be completed."
There are not any borings within the direct vicinity of the proposed detention pond. The
proposed detention pond bottom is 0.75 ft higher than the existing pond bottom. Currently
there is no exposed ground water or wetland vegetation, so it is assumed adequate separation
from groundwater is achieved.
Page 2
STORM DRAINAGE CRITERIA
This drainage report was prepared to meet or exceed the City of Fort Collins Stormwater
Criteria Manual. The Criteria Manual and amendments to the Mile High Flood District's (MHFD)
Urban Storm Drainage Criteria Manual (USDCM) Volumes 1, 2 and 3 were referenced as
guidelines for this design.
HYDROLOGIC CRITERIA
The rational method was performed to calculate the peak runoff rates for each basin. Percent
imperviousness and runoff coefficients were calculated for each basin using the surface
characteristics of each basin. The time of concentration was calculated using City of Fort Collins
initial time of concentration and the intensity was calculated using the corresponding storm
rainfall depth and the City of Fort Collins' Intensity-Duration-Frequency Curve. The City of Fort
Collins area has a 2-yr, 1-hr rainfall depth of 0.82 inches and a 100-yr, 1-hr rainfall depth of 2.86
inches. These depths do account for the 1999 adjusted rainfall depths.
HYDRAULIC CRITERIA
The Heartside Hill storm drainage system will been designed to convey the minor and major
storm events through the combination of private drives, storm sewer pipes and swales. Runoff
flows determined with the rational method will be attenuated through the site. Inlet capacities
will be calculated using MHFD's spreadsheet UD-Inlet_v4.05.xlsm.
The Autodesk Hydraflow Express program will be used to compute the open channel hydraulics
and check the capacities of the drainage swales throughout the site. Flow velocities within
these swales will be reviewed and where flows are found to be supercritical, the swales will be
lined with turf reinforcement mat.
All swale and pipe outlets will be protected with riprap or suitable erosion protection methods.
Storm sewer pipe outlets will be protected using the requirements set by the USDCM for the
protection downstream of culverts.
All supporting calculations are located in the Appendix.
Page 3
DRAINAGE BASINS
The Heartside Hill developed drainage basins are delineated by areas draining through the site.
The drainage basins are placed to limit the runoff flowing from the site into Brittany Street. The
site is broken into 3 main drainage systems:
Drainage Basin D1:
Drainage Basin D1 has an approximate area of 3.74 acres and is approximately 39.8%
impervious. This basin consists of a portion of the existing church property and building, the
future community center, the H4H single-family lots, and the park and open space. Runoff is
conveyed via swales to a curb cut and is conveyed through Rain Garden D1 to detention Pond
D.
Drainage Basin D2:
Drainage Basin D2 has an approximate area of 4.65 acres and is approximately 37.9%
impervious. This basin consists of six low-income housing lots, private drives, parking areas, and
detention Pond D. Runoff is conveyed to Pond D via swales, culverts and curb & gutter. Sub-
Basins D2a, D2b, D2c, and D2d divide the overall Basin D2 for conveyance element sizing and
capacity confirmation.
Drainage Basin OS1:
Drainage Basin OS1 pertains to the drainage from the existing improvements in Lot 1. This basin
has an approximate area of 2.03 acres and is approximately 65.4% impervious. This basin
consists of half of the existing church building, private drives, parking areas, and open space.
Runoff is conveyed via roadways to a swale and to Rain Garden OS1 and ultimately to detention
Pond D. A drainage easement is provided along the pathway to the detention pond.
Page 4
DRAINAGE FACILITY DESIGN
DRAINAGE CONVEYANCE DESIGN
Storm infrastructure to convey runoff will include swales, inlets, and storm sewer pipes.
Stormwater detention and water quality enhancement are achieved through the use of
detention Pond D and Rain Garden D1.
DETENTION�4VATER QUALITY POND DESIGN
An extended detention basin, Detention Pond D, will be utilized as the detention and water
quality facility for Heartside Hill. For the preliminary drainage study, the FAA method was used
to determine the detention volume needed. MHFD is referenced for the standard water quality
capture volume (WQCV) with a 40-hr drain time. Below is a brief summary of the proposed
design for the pand:
Pond D:
Extended detention basin for both Lots 1 and 2 with standard water quality treatment. A 100-yr
orifice plate maximizes volume in the pond and restricts release rate into the existing
stormwater system. The existing 100-yr release rate into the existing stormwater system is 13.2
cfs according to the Drainage Investigation for Heart of the Rockies Christian Church, prepared
by Messner Engineering, Inc (Revised June 29, 1999). This release rate was established prior to
the Fossil Creek Basin Master Drainage Plan update and is assumed to be included in the master
plan. The 100-yr water surface elevation is 4911.03 feet, with a maximum depth in the pond of
3.28 feet. During an event that exceeds the 100-yr storm, or the pond outlet should be
obstructed, overtopping will occur along on the east side of the pond into Lemay Ave.
Pond Summary Table
100-
Yr 100-yr Detention Combined Total pond WQCV 100-yr Max
Pond Peak Peak WQCV Volume Volume Volume gottom WSE WSE Depth
Inflow Release (ac-ft) �ac-ft) (ac-ft) Provided �ft) (ft) (ft) (ft)
cfs (cfs) (ac-ft)
Pond 44.16 13.20 0.08 0.82 0.90 1.46 4907.75 4908.86 4911.03 3.28
D
Page 5
LOW IMPACT DEVELOPMENT
The City of Fort Collins updated the Low Impact Development ordinance in 2016 (Ordinance No.
007, 2016) to require:
• Treat at least 75% of any newly developed or redeveloped impervious area using one or
a combination of LID techniques, or
• Treat at least 50% of any newly developed or redeveloped impervious area using one or
a combination of LID techniques when 25% of private driveable surfaces are permeable.
To satisfy the required implementation of Low Impact Development (LID) techniques, Heartside
Hill utilizes two (2) a bioretention ponds, Rain Garden D1 and Rain Garden OS1. Due to site
constraints and the inability to treat the required amount of newly developed impervious area,
the Rain Garden D1 is designed to treat a portion of the newly developed impervious area able
to be directed to the bioretention pond, and Rain Garden OS1 is designed to treat the existing
church impervious area. The rain gardens are designed to treat the total drainage area being
directed to the rain garden. The result is that with the combination of both rain gardens, an
equivalent of 83% of the total onsite impervious area is treated by a LID feature. The water
quality capture volume provided within the LID features is: Rain Garden D1 is 2,914 cu-ft, and
within Rain Garden OS1 is 1,845 cu-ft. Standard water quality capture volume is 0.08 ac-ft,
treating the remaining area that is directed to Pond D. Both the LID and standard WQCVs
provide an additional 20% volume to account for potential loss of volume due to the
accumulation of sediment.
Below is a description of the 4-step process for selecting structural BMPs:
Mile High Flood District (MHFD) recommends a Four Step Process for receiving water
protection that focuses on reducing runoff volumes, treating the water quality capture volume
(WQCV), stabilizing drainageways and implementing long-term source controls. The Four Step
Process applies to the management of smaller, frequently occurring events.
Step 1: Employ Runoff Reduction Practices
To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement Low
Impact Development (LID) strategies, including Minimizing Directly Connected Impervious
Areas (MDCIA).
Page 6
Captured runoff from strategic areas are routed through bioretention pond/rain gardens. Rain
gardens will slow runoff, promote infiltration, and filter runoff prior to being released into the
adjacent storm drain system.
Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release
The bioretention pond/rain gardens are designed to provide water quality capture volume per
Urban Drainage's recommendations and calculations. The captured runoff is designed for a 12-
hr drain time.
Step 3: Stabilize Drainageways
Natural Drainageways are subject to bed and bank erosion due to increases in frequency,
durativn, rate and volume of runoff during and following development. Because the site will
drain to an existing storm system, bank stabilization is unnecessary with this project.
Step 4: Implement Site Specific and Other Source Control BMPs
The proposed project will improve upon site specific source controls compared to historic
conditions by providing localized trash enclosures within the development for disposal of solid
waste; a rain garden for water treatment prior to flows entering storm systems; and additional
water quality measures to protect and prolong the design life of BMPS delineated in Step 1.
Below is the Low Impact Development summary and all calculations are attached for reference.
LID Treatment Summary
Total Proposed Impervious Area 155,022
Total Impervious Area LID Treated (sq-ft) 128,370
Total % Impervious Area LID Treated 83%
Water Quality Area Treatment Summary
Description Area Area
(sq-ft) (acres) Treatment Ratio
Total Area Treated by LID 251,618 5.78 53.6%
Total Area Treated by EDB 202,366 4.65 43.1%
Total Area Not Treated 15,641 0.36 3.3%
Total Improvement Area 469,625 10.78 100.0°/a
Page 7
STORMWATER POLLUTION PREVENTION
Erosion and sedimentation will be controlled on-site by use of sediment control logs, inlet
protection, and gravel construction entrances. The measures are designed to limit the overall
sediment yield increase due to construction as required by the City of Fort Collins. During
overlot and final grading the soil will be roughened and furrowed perpendicular to the
prevailing winds.
During the performance of the work required by these specifications or any operations
appurtenant thereto, whether on right-of-way provided by the City or elsewhere, the
contractor shall furnish all labor, equipment, materials, and means required. The Contractor
shall carry out proper efficient measures wherever and as necessary to reduce dust nuisance,
and to prevent dust nuisance that has originated from his operations from damaging crops,
orchards, cultivated fields, and dwellings, or causing nuisance to persons. The Contractor will be
held liable for any damage resulting from dust originating from his operations under these
specifications on right-of-way or elsewhere.
It is unlawful to track or cause to be tracked mud or other debris onto public streets or rights-
of-way. Wherever construction vehicles access routes or intersect paved public roads,
previsions must be made to minimize the transport of sediment by runoff or vehicles tracking
onto the paved surface. Stabilized construction entrances are required with base material
consisting of 6" coarse aggregate. The contractor will be responsible for clearing mud tracked
onto public streets on a daily basis.
All temporary and permanent erosion and sediment control practices must be maintained and
repaired as needed to assure continued performance of their intended function. Maintenance
is the responsibility of the contractor.
All disturbed areas must be seeded and mulched within 30 days of project start. Vegetation
shall not be considered established until a ground cover is achieved which is demonstrated to
be mature enough to control soil erosion to the satisfaction of the City Inspector and to survive
severe weather conditions.
Reference the "Erosion Control Report for Heartside Hill" for more detailed information.
Page 8
CONCLUSIONS
This Final Drainage Report for Heartside Hill has been prepared to comply with the stormwater
criteria set by the City of Fort Collins. The proposed drainage system will be designed to convey
the developed peak 100-yr storm water runoff through the site to the proposed detention
pond, and ultimately to the existing storm system. Drainage conveyance systems is designed to
convey drainage to the proposed roadways and collect onsite drainage and treat it in
accordance with LID requirements before discharging it into the proposed detention pond. This
drainage report anticipates the implementation of best management practices for erosion
control, temporary and permanent, and on-site construction facilities.
It can therefore be concluded that development of Heartside Hill complies with the storm
water jurisdictional criteria and the approved City of Fort Collins Stormwater Criteria Manual
and will not adversely affect the adjacent properties, streets, storm drain system and/or
detention/water quality facilities.
Page 9
REFERENCES
1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Mile Hi�h Flood Control
District, Updated January 2016.
2. Fort Collins Stormwater Criteria Manual, Fort Collins Utilities, City of Fort Collins,
Colorado, Dated December 2018, Adopted January 2019.
3. "Hydrologic Group Rating for Larimer County Area, Colorado", USDA-Natural Resources
Conservation Service, National Cooperative Soil Survey. Web Soil Survey URL:
http://websoilsurvey.nres.usda.gov. [11/15/2021]
4. "Preliminary Geotechnical Subsurface Exploration Report, Proposed Residential
Development Lots 1 and 2, Heart of the Rockies Second Subdivision", prepared by
Soilo�ic, LLC, Dated August 13, 2021.
5. "Drainage Investigation for Heart of the Rockies Christian Church", prepared by Messner
Engineering, Inc., Dated June 29, 1999.
Page 10
APPENDIX
Appendix A— Site Descriptions, Characteristics, & References
Appendix B — Rational Calculations
Appendix C — Pond Calculations
Appendix D— Low Impact Development Calculations
Appendix E— Inlet, Pipe, & Swale Capacity Calculations
Page 11
APPENDIX A— SITE DESCRIPTIONS, CHARACTEIZISTICS, & REFERENCES
Appendix A
HEARTSIDE HILL
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Vicinity Map
Scale: 1" = 1000'
PROJECT DATUM: NAVD88
CITY OF FORT COLLINS BENCHMARK #24-94
ON THE NORTHEAST CORNER OF THE INTERSECTION OF EAST TRILBY ROAD AND PORTNER DRIVE, ON TOP OF THE WEST END
OF A CONCRETE HEADWALL
ELEV= 4960.69
CITY OF FORT COLLINS BENCHMARK #25-94
ON THE NORTHWEST CORNER OF THE INTERSECTION OF EAST TRILBY ROAD AND SOUTH LEMAY AVENUE, ON TOP OF THE
SOUTHEAST EDGE OF THE CONCRETE RING TO AN ELECTRIC MANHOLE
ELEV= 4913.16
PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING DEVELOPMENTS HAVE USED
NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) FOR THEIR VERTICAL DATUMS.
IF NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) IS REQUIRED FOR ANY PURPOSE,
THE FOLLOWING EQUATIONS SHOULD BE USED:
NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) = 4960.69 (NAVD88 DATUM� - 3.19'
NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) = 4913.16 (NAVD88 DATUM� - 3.19'
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Hydrologic Soil Group
Map unit symbol
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Rating
Acres in AOI I Percent of AOI
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percent slopes
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9 percent slopes
Totals for Area of Interest
Description
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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. Soiis 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 c�ay
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
93.8%
100.0%
US�n Natural Resources Web Soil Survey 12/21/2021
� Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group—Larimer County Area, Colorado
Component Percent Cutoff.� None Specified
Tie-break Rule: Higher
USDn Natural Resources Web Soil Survey 12/21/2021
� Conservation Service National Cooperative Soil Survey Page 4 of 4
National Flood Hazard Layer FI RMette
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FORT COLLINS STORMWATER CRITERIA MANUAL
Hydrology Standards (Ch. 5)
3.0 Rational Method
Table 3.4-1. IDF Table for Rational Method
Duration
Intensity Intensity Intensity
(min) 2'Year 10-year 100-year
(in/hr) (in/hr) (in/hr)
5 2.85 4.87 9.95
6 2.67 4.56 9.31
7 2.52 4.31 8.80
8 2.40 4.10 8.38
9 2.30 3.93 8.03
10 2.21 3.78 7.72
11 2.13 3.63 7.42
12 2.05 3.50 7.16
13 1.98 3.39 6.92
14 1.92 3.29 6.71
15 1.87 3.19 6.52
16 1.81 3.08 6.30
17 1.75 2.99 6.10
18 1.70 2.90 5.92
19 1.65 2.82 5.75
20 1.61 2.74 5.60
21 1.56 2.67 5.46
22 1.53 2.61 5.32
23 1.49 2.55 5.20
24 1.46 2.49 5.09
25 1.43 2.44 4.98
26 1.4 2.39 4.87
27 1.37 2.34 4.78
28 1.34 2.29 4.69
29 1.32 2.25 4.60
30 1.30 2.21 4.52
31 1.27 2.16 4.42
32 1.24 2.12 4.33
33 1.22 2.08 4.24
34 1.19 2.04 4.16
35 1.17 2.00 4.08
36 1.15 1.96 4.01
37 1.16 1.93 3.93
38 1.11 1.89 3.87
�`�rt��
Duration
Intensity Intensity Intensity
2-year 10-year 100-year
(min) (in/hr) (in/hr) (in/hr)
39 1.09 1.86 3.8
40 1.07 1.83 3.74
41 1.05 1.80 3.68
42 1.04 1.77 3.62
43 1.02 1.74 3.56
44 1.01 1.72 3.51
45 0.99 1.69 3.46
46 0.98 1.67 3.41
47 0.96 1.64 3.36
48 0.95 1.62 3.31
49 0.94 1.6 3.27
50 0.92 1.58 3.23
51 0.91 1.56 3.18
52 0.9 1.54 3.14
53 0.89 1.52 3.10
54 0.88 1.50 3.07
55 0.87 1.48 3.03
56 0.86 1.47 2.99
57 0.85 1.45 2.96
58 0.84 1.43 2.92
59 0.83 1.42 2.89
60 0.82 1.4 2.86
65 0.78 1.32 2.71
70 0.73 1.25 2.59
75 0.70 1.19 2.48
80 0.66 1.14 2.38
85 0.64 1.09 2.29
90 0.61 1.05 2.21
95 0.58 1.01 2.13
100 0.56 0.97 2.06
105 0.54 0.94 2.00
110 0.52 0.91 1.94
115 0.51 0.88 1.88
120 0.49 0.86 1.84
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 8
FORT COLLINS STORMWATER CRITERIA MANUAL
Hydrology Standards (Ch. 5)
3.0 Rational Method
Figure 3.4-1. Rainfall IDF Curve — Fort Collins
io.00
9.00
8.00
7.00
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0
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_— .—�— — — , - ----
o.� _ ---- - _ .
0 10 20 30 40 50 60 70 80 90 100 110 120
Storm Duration (minutes)
c�tyof 3.4 Intensity-Duration-Frequency Curves for Rational Method
�„�rt� S Page 9
0��
(c.l.s.)
17.C5
6.A6
17.99
6.h4
26.65
7?.87
CONSTRUCiiON SE�UENCE
SiANDARp F�RM C
PRQIECi_ NEAHL Of THF HOLKIE$ CMRiSTAN CNURLH
SEOUENLE �OR ]99fl OULY COMFLEfE� B�: u6SNFR� MTE: a-2t-98 .
INDIGTE HY USE OF A BAP LINE OR S'MBOLS WMEN EHOSION COMROt MEASUR6 WILL BE
INS�ALLFO. AWOR MODIi1GT10N5 TO PN APPROVEO SCHEDULE M1Y REOUIRE SUBMTiNG ♦
NEW SCME�ULE FpR APPROVAL Bt iHE q1Y ENCINEER.
.un I +ses I
wrRior cnnon+c nmin
wiNO ERpSqN CONLROL
et 9�eome.
neaaro�oi ea.„.�.
vegetalne M netle
Soil S onl e
O��r� (Waler bVlicatian) IIIIIII1111111�11
r?AINFpu CROSION CONixOI
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ia nte�. innnuninni
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S�IICNRES: �NS�P1lE0 6� HAIMNNm B!
�£GEf,1TON / MIIICHINC CONIaACTOR
onlc sueMrtho _ nvvaovco er crry or rom caurvs ory
EROSION CONTROL NOTES:
The City of Fort Collins Stormwoter Utility erosion control inspectar must be notified
af least 24 hours prior to any construction on lhis s1te.
All required perimeter silt fencing shall be install orior to any land disturbing
activib� (stockpiling, stripping, grading, etc,), All other required control meosures
sholl he installed at the apprnpriate time in the construction sequence os indicated
in the apDroved project scheAule, canstruction plans, ond erosion co�trol report.
Pre—Cisturbonce vegetation shall be protected and retained wherover possible.
Remo�al or disturbance of existing vegetation shall be limiled to the areo required
for immediate construction operotlons, and for the shortest practical period of time.
All sois exposed during land disturbing octNity (sfripping, groding, utility insta�lations,
stockpiling, fflling, etc.) Shall be kept in a roughened condition by ripping or
discinq olong land contours until mulch, vegetation, or olher permanemt erasion
contrci is instolled. No soils in areas outside project street rights of way shall
remoin eaposed by lond dislnrbing activity (or more than thirty (30) days before
re0uired temporory or perm�.�nent erosion control (e.g. seed/mulch, IondscoD�ng,
etc.) �s installed, unless othrrwise apOroved by the Stormwoter Utility.
The Froperty sholl be watered and mointained ot all Cmes during construction
octivftes so as to prevent wind—caused erasion. All land disturbing activities sholl
be irrmedotely discon6nued when /ug�tive dust impacts adjacent properties, os
detern;ned by the Clty of Port Collins Engineering Department.
AIl ternporory (structurol) erosion control measures shall be lnspected and repaired
or re-onstructed ae necessary after each r noff event to ossure con6nued
perfornonce of their function. NI relained sedlments, particularly those on poved
�oadwry surfoces, sholl be removed and disvosed of in o monner ond location
so as not to cause the,�r release into any drainageway.
No scil stockpile shall exceed ten (10) feet in heighL All soil stockpiles s�all be
protected from sediment tronsport by suAace roughening, wotering, and Derimeter
sflt fe�cing. Any soil siockpile remvining after 30 days shall be seeded and mWched.
�\ � CIty Ordinance prohibits the Irocking, dropping, or depositing of soils or soils or
\ oj�y othe� moteriol onto City streets by or from any vehlcle. Any inadvertontly
\ � d�pos�ited materiol sholl be deaned immediotely by the controctor.
`j� � Exsting RCP �
` ���.�\ Storm Drain Lines I
�� �
i
�� �'�\� �
� ��� ��,��� � �
� �
�\\ � � Existinq � � T 25 i o0
///��� � � �\ / 21" RCP � � 1 �
. y /a '�� �\ V Storm Droin � o so � so
Y��. ilndicates ` \� .s0 2.95 ac. 1" = 50'
� � PropOsed a �� � � -- x #4i L� Contour Interval: 1'
.� ~='SiR Fence' �
A � �, �,a�e 1 .91 ac. Basin 'B'
6.5 22.
� o `- �'4 26'� � p Existing 6'
, I " .83 Crosspan
Drainage� � '�
Swale I` ' �- :1- • + . .' Inv. 21" = 03.76
\ -
� �� ��� � � ��`� D /
, _.
,.
� Indicates Pkopo9ed � \ � � �� � � �
P Straw Bdle Dike -- - - �oo � Proposed Straw
� _ k � :�I Bale Filter
\
\ �
� .�_ _ y� �
�
�
� ;I �
3:78 ac. #2
aa5��i � '
` s.a is. •A� ,
\Sett�ing Bosi� I
� " 25' '�
� � #3 I ��
5.26�aG,. Bosin '�'
1.6 6. �'� dded
' � S�eded�
�'�'� rea �
b.' �. �
���� B
<.�.
� —� �M^/L ��
D�i A,.;:� Ve l.
F_I v��l4n�+��^�
Proposed 'S�I:�en'ce'J :
, in Swnle _�Typi�al) 4
:Fi I
� t�._
.�
I� Settling Basin
IIOutlet Structure
� I SEE DETAIL
I � I
�� > �
IQ I
1 �
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IB �
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D �
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� I
I I ' il �TYPein R' 11�nlet
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:�, :E.>: � �
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— — �\� �
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���
u �
� sai2 _ - Typ�cally r,Gicates _..'s:'�g
Ground Surface Contour
�o�� Typically Indicates Proposed
Fin�sh Surface Contour
�� �' Drainage Basin Limit Identifier
Typically Indicates Flowline
-�oo� of Ditch or Swale
Typicolly Indicates Silt Fence
Typically Indicates Straw Bale
� Filter or Dike Applicotion
Typically Indicates Existing
x 99•1 � Povement Surface Elevotion
or Flow Line of Gutter
Typically Indicates Proposed
8.0 Pavement Surface Elevation
+ or Flow Line of Gutter
�o Typically Indicates Drainoge
Flow Direction
�, Concentration Point Identifier
��: L'as�n'B' -- Design po;^'.� B^si^ N,i�mhcr
3.15 ac. Area of in Acres
Qioa c.f.s.
3.4 9.7
I QZ C.f.S.
•
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DATE: APR 17.1998
SCALE: AS NOTED
ORAWN: M.S.R.
CHKD: D.R M.
Project No.
GRD-282-98
SHEET
3 of 6
City of Forf Collins, Colorado
UTILITY PLAN APPROVAL
APPROVED:
Director o ngmeenng
CHECKED BY:
Water ostewater Utility
CHECKED BY:
ormwo er i i y
CHECKED BY:
orks ecreat�on
CHECKED BY:
CHECKED BY:
666[ 46�1i-o[ 50 �eyl cdd �.Oa;7ol
'
��
DRAINAGE INVESTIGATION CALCULATIONS
' Clierrt: ARCHITECTURE ONE Project No: GRD-282-98
Project: HEART OF THE ROCKfES CHRlSTlAN CHURCH Date: Apr. 22, 1998
Location: Lot1, BIk1, Heart of the Rockies 2nd Subd., Fort Collins, CO By: D.R.M.
. Rev. 3/28/99
' PROPOSED CONDITtONS: (continued)
DETERMINE OUTLET CONTROL StZING FOR SETTLING BASIN:
' Refer to attached Figure 13 and Figure 5- 3 for Outlet Sizing
Detention Volume to be provided at 2 ft. depth = 3,600 cu. ft. = 8.083 ac. - ft.
' Depth = 2.0 feet
' From Figure 5- 3 required "Area per Row" = 0.17 sq. in.
Minimum of eight (8) holes per row is to be provided.
' Therefore, the size of each hole is: 0.17 / 8= 0.02125 sq. in. per hole
Try 1/8 in. diameter holes at 0.013 sq. in. per hole
, 0.17 / 0.0't3 = 13 hole per row with 1/8 in. dia. hole
' For pipe with 13 cotumns (hales per row) use 6 in. dia. pipe from Figure 13.
DETERMiNE PIPE SfZE FOR DtSCHARGE FROM SITE: Allowed Release Rate
, Refer to the "Supplement to the Final Drainage Report foot Brittany Knolls P.U.D. - Filing 2" (See Attacheci;
From Table 3 the maximum capacity for the dawnstream receiving 30" dia. pipe is 29.0 c.f.s.
' From table 3 the maximum capacity of the 2i" dia. pipe is 19.4 c.f.s. with a desi�n discharge of 13.2 c.f.s.
, The estimate Q�no for the proposed site at Basin "A" D.P. #1 + D.P. #2 + D.P. #3 = 2fi.65 c.f.s.
Therefore, ponding wili occur in the swale section adjacent to Lemay Avenue during the 100 Year Storm.
n 8asin"A" D.P.#1 + D.P. #2= Q2 = CIACf = 3.23 x I x 1.25 = 4.04 x I(in./hr.)
' Time Q�oo Volume RELEASED Vol.Rei�e Voiume Det.
min. c.f.s. cu. ft. c.f.s. cu. ft. cu. ft.
' 1Q 28.87 17,321 13.20 7,920 9,4Q1
Basins w/ �5 24.23 21,802 13.24 11,880 9,922
Improvements
. 20 21.00 25,194 13.20 15,840 9,354 Detention Volume
' 25 18.57 27,859 13.20 19,800 8,059
30 16.96 30,523 13.20 23,760 6,7fi3
' The�efore, 9,922 cu. ft. of detention ponding volume is required in the swale sectian adjacent to Lemay Avf
Page 10 of 11
' his unofficial copy was downloaded on Nov-12-2021 fi-om the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
or additional information or an official copy, please contacC CiCy of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
APPENDIX B — RATIONAL CALCULATIONS
Appendix B
�
BAS�N SUMMARY:
� 2ryr Veak Runoff 10-yr l
a�nt haa n �aresl Imper�ous 4 n ce [IA1 ntensit 4: t nmr[oe
Iminl ulCfr�ol R lac ezi Illn/nr)Y Ift'Izl Iminl ulCz.cl
Pond Summary Table
100-yrVeakRunoff 100-yr 100-yr pzteMion Cwnbi�d T�a� Pond WQCV t00ryr PAaa
�� c�p) mie�9ry 4�oo Peak Peak WQCJ Volume
Pond Volume Volum Bottom WSE WSE Depth
(c� � (ecrez� �In/hr) (R'/s) ��bw Release (ao-ft) �an�l (ao-fl)Q ProvideA �ft7 (Fl) (i� (R)
(c[s) �cfs) (ao-(t)
PontlD 44.16 13.20 0.08 082 0.90 123 490].]5 4908.&5 491103 3.28
- - _ EX 50 /NLET-0?
�3 sa
- .--`_ -
o-oz o-eo s9' c.oz �-,-- - -•-��_ - "_ _ �
--- � EX 34.00' <�=-'. ..
ROW "
o9s �ab sss ws� ,.. p so �: �
ie � te" �_' �'\ \
�_ ' �ti-� --':� / J � � � �
// I'� g^p / EX 35.50' � '� Sy`7S�
�% � I ' �. . ROW -�---_� ' �
�/.�'' - _'. -�� I � - � .
/ � �! �'_ - - - _ _ _ _ ! � EX SD /NCET 03 �)
l / __ �\ � �
BRITTANY KNOLLS / ` � �r � � I � \ \ �7�'`� ` qo �
>� � : t,k ; I v
= f A
ex so iNcer-aa i ��� ,� �, �'�` �\ ;. � � � i . , ���/ . � � � � � ��.'�_�._-
ss RAIN GARDEN O51 _ � %' � � � � � � \
r ;
i
"� ' ' WQCV(12HR)=1845CU-FT �� � � . �/�BLOCKI / �'� ��
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Heartside Hill
DEVELOPED IMPERVIOUS AREA CALCULATION
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 20-1045-00
Date: May 10, 2023
DESIGN CRITERIA:
Fort Collins Stormwater Criteria Manual
BASINS:
% Impervious values from Table 3.2.2 in the Fort Collins Stormwater Criteria Manual
Runoff Coefficients and Frequency Adjustment Factors for City of Fort Collins - Storm Water Criteria Manual
Land Use � Runoff
Impervious Coefficient C
Paved 100% 0.95
Roof 90% 0.95
Walks 90% 0.95
Single-Family (SF) Lots 45% 0.55
Community Center (CC) Lot 70% 0.65
Lawns
(Heavy, 2•7% Slope) 0% 0.25
frequency
Return Adjustment
Period Factor (Cf)
2-yearto 1.00
10- ear
100-year 1.25
Sub-basin Aro�,� A�o�,i AP,�Qa A.00r Awaie AsFio: Acuoc %4aw� Weighted% COMPOSITE
Designation (sq feet) (acres) (sq feet) (sq feet) (sq feet) (sq feet� (sq teet) (sq feet) Impervious C to C C
z ia ioo
OSi 88,538 2.03 45,364 3,889 6,687 0 0 29,595 65.4% OJ2 0.89
Dl 163,080 3.74 24,710 3,742 5,916 33,798 23,353 71,561 39.8% 0.52 0.65
D2a 48,086 1.10 0 12,931 1,430 0 0 33,725 26.9% 0.46 0.57
D26 42,280 0.97 231 12,931 1,857 0 0 27,262 32.0% 0.50 0.62
02a+D26 90,366 2.07 231 25,861 3,287 0 0 6Q987 293% O.CS 0.60
D2c 67,394 1.55 44,316 0 4,531 0 0 18,546 71.8% 0.76 0.95
D2d 44,606 1.02 0 0 2,055 0 0 42,551 4.1% 0.28 035
D2 202,366 4.65 44,547 25,561 9,874 0 0 122,084 37.9% 0.53 0.66
Total 453,984 10.42 1ll,621 33,492 22,476 33,795 23,353 223,244 44.0% 0.56 0.70
21-1045-00 Rational Calcs.xisx Page 1 of 5 Highland Development Services
lTRATION
opment Services
ria Manual
Fort Collins Stormwater Criteria Manual
1.49
uation 5-3 V= - R2�3 S 1�2 -Equation 5-4
n
L
I�, = L-I- 1 � -Urbanized Check Equation 3.3-5
I80
�FC Overland Flow �t ���
�w shall not exceed for developed condition
�w shall not exceed for undeveloped condition
t� and urbanized basin check
minimum t� = 5 min for urbanized basins
0 10-yr)
INITIAL/OVERLAND TIME TRAVEL TIME (tt) Urban Check
(t.) Final
t� t;+t,
HYDRAULIC t�
AREA LENGTH SLOPE t; LENGTH SLOPE ROUGHNESS VELOCITY tt (min) OVERALL LENGTH t�
-z-io (acres) (ft) (ft/ft� (min) (ft) (ft/ft) RADI,US COEFFICIENT (min)
(ft/s) (min) (ft/ft) (min)
).72 2.03 240 0.0351 7.12 457 0.0128 0.10 0.016 2.27 3.36 10.48 697 13.87 10.48
).52 3.74 300 0.0252 13.36 46S 0.0433 0.10 0.016 4.17 1.57 15.23 768 14.27 14.27
).46 1.10 75 0.0760 SZ9 371 0.0392 0.14 0.030 2.65 233 7.62 446 12.48 7.62
).50 0.97 18 0.1470 1.96 391 0.0343 0.14 0.030 2.48 2.63 5.00 409 12.27 5.00
).76 1.55 109 0.0504 3.89 521 0.0389 0.10 0.016 3.96 2.20 6.09 630 13.50 6.09
).28 1.02 93 0.0492 8.65 233 0.0050 0.14 0.030 0.94 4.11 12.76 326 11.81 11.81
).56 10.42 240 0.0381 10.00 1048 0.0272 0.10 0.030 1.77 9.59 19.89 - - 19.89
Page 2 of 5 Highland Development Services
lTRATION
opment Services
ria Manual
Fort Collins Stormwater Criteria Manual
uation 5-3
1.49 2�3 [� 1/2
V= - R J -Equation 5-4
n
j.. = L+ 1 Q -Urbanized Check Equation 33-5
180
�FC Overland Flow
L
�' 60V
�w shall not exceed for developed condition
�w shall not exceed for undeveloped condition
t� and urbanized basin check
minimum t� = 5 min for urbanized basins
r)
INITIAL/OVERLAND TIME TRAVEL TIME (tt) Urban Check
(t.) Final
t� t;+t�
HYDRAULIC tc
AREA LENGTH SLOPE t; LENGTH SLOPE ROUGHNESS VELOCITY ti (m��) OVERALL LENGTH t�
C10° (acres) (ft) (ft/ft� (min) (ft) (ft/ft� RADIUS COEfFICIENT (min)
(ft) �ft/s� (min) (ft/ft) (min)
).89 2.03 240 0.0351 3.50 457 0.0128 0.10 0.016 2.27 3.36 7.16 697 13.57 7.16
).65 3.74 300 0.0252 10.40 46S 0.0433 0.10 0.016 4.17 1.87 12.27 768 14.27 12.27
).57 1.10 75 0.0760 4.34 371 0.0392 0.14 0.030 2.65 2.33 6.67 446 12.48 6.67
).62 0.97 18 0.1470 1.56 391 0.0343 0.14 0.030 2.48 2.63 5.00 409 12.27 5.00
).95 1.55 109 0.0504 1.74 521 0.0389 0.10 0.016 3.96 2.20 5.00 630 13.50 5.00
).35 1.02 93 0.0492 7.90 233 0.0050 0.14 0.030 0.94 4.11 12.02 326 11.51 11.81
).70 10.42 240 0.0381 7.40 1048 0.0272 0.10 0.030 1.77 9.89 17.29 - - 17.29
Page 3 of 5 Highland Development Services
evelopment Services
21, 2021
Criteria Manual
peak discharge (cfs)
�unoff coefficient
�infall intensity (in/hr)
drainage area (ac)
1 = rainfall intensity (in/hr)
P 1= one-hour point rainfall depth (in)
2g•SP t� = time of concentration (min)
� �1 �+ t� ��o.�s66st) p _ 0.82 in
1 2yr -
P�-soyr = 1.40 i1l
Pi-iooyr = 2.86 in
2-yr Peak Runoff 10-yr Peak Runoff 100-yr Peak Runoff
/
�ervious
t� Runoff Coeff C�A) Intensity Qz t� Runoff Coeff C(A) Intensity Qia t� Runoff Coeff. C�A) Intensity Qloo
(min) (�z-io) (acres) (in/hr) (ft3/S) (min) (�z-io) (acres) (in/hr) ({�'/S) (min) (�iaa) (acres) (in/hr) (ft3/5)
65.4% 10.48 0.72 1.46 2.17 3.16 10.48 0.72 1.46 3.71 5.40 7.16 0.89 1.82 8.71 15.84
39.8% 14.27 0.52 1.94 1.90 3.68 14.27 0.52 1.94 3.25 6.28 12.27 0.65 2.42 7.10 17.17
26.9% 7.62 0.46 0.51 2.45 1.24 7.62 0.46 0.51 4.18 2.12 6.67 0.57 0.63 8.91 5.64
32.0% 5.00 0.50 0.48 2.85 1.38 5.00 0.50 0.48 4.87 2.36 5.00 0.62 0.60 9.95 6.02
71.8% 6.09 0.76 1.17 2.63 3.08 6.09 0.76 1.17 4.49 5.26 5.00 0.95 1.46 9.95 14.57
4.1% 11.81 0.28 0.29 2.07 0.60 11.81 0.28 0.29 3.53 1.02 11.81 0.35 036 7.21 2.61
44.0% 19.89 0.56 5.84 1.61 9.43 19.89 0.56 5.84 2.76 16.10 17.29 0.70 7.30 6.05 44.16
Page 4 of 5 Highland Development Services
Heartside Hill
Attenuated Flows
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: May 10, 2023
DESIGN CRITERIA:
Fort Collins Stormwater Criteria Manual
EQUATIONS:
t� = t{ + tt -Equation 5-3
1.87�1.1 - CCf�y� _CoFC Overland Flow
T� 50.33
V_ 1.49 R2�3 5. 1�z _Equation 5-4
n
L
tt 60V
CONSTRAINTS:
300 ft- Overland flow shall not exceed for developed conditior Final t� = minimum of t; + tt and urbanized basin check
500 ft- Overland flow shall not exceed for undeveloped conditior recommended minimum t� = 5 min for urbanized basins
Q� = n-yr peak discharge (cfs)
C� = n-yr runoff coefficient
Qn = Cn�n'4
I„ = n-yr rainfall intensity (in/hr)
A = drainage area (ac)
28.5P1
I �1� .� t��0.7II6
I = rainfall intensity (in/hr)
P, = one-hour point rainfall depth (in)
t� = time of concentration (min)
P�-zy� = 0.82 in.
P,-,oy� = 1.40 in.
P�-,00y� = 2.86 in.
BASINS:
DP/Manhole D2b
Contributing Basins D2a+D2b
Contributing Area (acres) 2.07
Runoff Coefficients
Overland Flow Time
Length (ft)
Slope (%)
t; (min)
Travel Time
Cz-io C�oo
0.48 0.60
75
7.60
2-yr to
10-yr 100-yr
5.14 4.15
Length (it) Slope (%) Hydraulic Roughness Velociry (ft/s) t� (min)
Radius (ft) Coefficient
371 3.92% 0.10 0.016 3.97 1.56
84 2.74% 0.10 0.016 3.32 0.42 pipe conveyance
320 4.03% 0.10 0.016 4.03 1.32
Total Time 3.30
Final Time of Concentration - tc (min)
2-yr to
10-yr 100-yr
8.44 7.45
Intensities (in/hr)
2-yr 10-yr 100-yr
2.36 4.03 8.60
Discharge (cfs)
2-yr 10-yr 100-yr
2.34 3.99 10.65
APPENDIX C — POND CALCULATIONS
Appendix C
Heartside Hill
Pond Summary
Design Engineer:
Design Firm:
Project Number:
Date:
J.Claeys
Highland Development Services
21-1045-00
May 10, 2023
Pond Summary Table
100-yr 100-yr Total
Detention Combined Pond WQCV 100-yr Max
Peak Peak WQCV Volume
Pond Volume Volume Bottom WSE WSE Depth
Inflow Release (ac-ft) �ac-ft) (ac-ft) Provided �ft) (ft) (ft) (ft)
cfs cfs ao-ft
Pond D 44.16 13.20 0.08 0.82 0.90 1.23 4907.75 4908.85 4911.03 3.28
21-1045-00 PondCalcs.xlsx Page 1 of 7 Highland Development Services
Heartside Hill
100-yr Detention Volume - FAA Method
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: May 10, 2023
DESIGN CRITERIA
Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual
City of Fort Collins - Storm Water Criteria Manual
Detention Volume Calculation - Pond D
Runoff Coefficient (C) 0.56
Frequency Factor (C�) 1.25
Adjusted Runoff Coefficient (CC�) 0.70
Area (A ) 10.42 acres
Allowed Release Rate 13.20 cfs
Time
(min)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
Required Detention
ft3 acre-ft
35,584 0.82
Detained
Volume
1 ft3)
0
17,813
25,866
30,921
33,176
34,686
35, 584
34,775
33,791
32,501
31,079
29,373
27, 579
25,895
23,904
22,001
19,967
17,867
15,767
13,316
10,954
8,744
6,272
4, 041
1,591
Detained
Volume
(acre-ft)
0.00
0.41
0.59
0.71
0.76
0.80
0.82
0.80
0.78
0.75
0.71
0.67
0.63
0.59
0.55
0.51
0.46
0.41
0.36
0.31
0.25
0.20
0.14
0.09
0.04
21-1045-00 PondCalcs.xlsx Page 2 of 7 Highland Development Services
100-yr
Intensity
(/, in/hr)
0.00
9.95
7.72
6.52
5.60
4.98
4.52
4.08
3.74
3.46
3.23
3.03
2.86
2.72
2.59
2.48
2.38
2.29
2.21
2.13
2.06
2.00
1.94
1.89
1.84
Q�oo
(cfs)
0.00
72.58
56.31
47.56
40.85
36.32
32.97
29.76
27.28
25.24
23.56
22.10
20.86
19.84
18.89
18.09
17.36
16.70
16.12
15.54
15.03
14.59
14.15
13.79
13.42
Accumulative
Runoff Volume
��3�
0
21, 773
33, 786
42, 801
49, 016
54,486
59, 344
62,495
65,471
68,141
70, 679
72, 933
75, 099
77, 375
79, 344
81,401
83, 327
85,187
87,047
88,556
90,154
91,904
93, 392
95,121
96, 631
Accumu�ative
Release
Volume
(ft3)
0
3,960
7, 920
11, 880
15,840
19,800
23,760
27,720
31,680
35,640
39,600
43,560
47,520
51,480
55,440
59,400
63, 360
67, 320
71,280
75,240
79,200
83,160
87,120
91,080
95,040
Heartside Hill
Water Quality Pond and Outlet Sizing - Pond D
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: May 10, 2023
DESIGN CRITERIA:
Urban Storm Drainage Criteria Manual (USDCM) Volume III, Urban Drainage and Flood Control District, June 2001 (Updated November 2010)
REQUIRED WATER QUALITY CAPTURE VOLUME (WQCV):
Tributary Area, A 4.65 acres Basin D2 (not treated by LID)
Composite. Imperviousness, I 37.9%
W qCV (watershed inches) (WQCV� 0.174 inches 40-Hour�Drain Time (Fig SQ-2)
Re uired WQCV Volume =; 12 * Area * 1.2 0.081 acre-feet Includin 20% for Sedimentation
WATER QUALITY OUTLET SIZING (Per USDCM, Volume 3):
Design Water Quality Depth, DWQ 1.10 ft
Determine Kao
Maximum Area per Row, a
Circular Perforation Sizing
Number of Rows, nr
K40 = 0.013DWQ2 + 0.22DWQ - 0.10
a=WQCV/Kao
0.158
Number of Columns, nc (See Table 6a-1 for Max.)
Choose Hole Diameter
Use USDCM Volume 3, Figure 5
Total Area per Row, Ao
Total Outlet Area, Ao,
Does design work?
Minimum Steel Plate Thickness
Rectangular Perforation Sizing (Not Used)
Number of Rows, nr
Choose Rectangular Hole Width (w/ 2" Height)
Use USDCM Volume 3, Figure 5
Total Outlet Area, Aot
Does design work?
Minimum Steel Plate Thickness
0.514 square inches
3 rows
Ocolumns
3/4 inches
0.750 inches
0.44 square inches
1.33 square inches
Yes
1/4 inch
2 rows
Dinches
0.000 inches
0.00 square inches
Yes
1/4 inch
21-1045-00 PondCalcs.xlsx Page 3 of 7 Highland Development Services
Heartside Hill
Water Quality Pond and Outlet Sizing - Pond D
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: May 10, 2023
WATER QUALITY TRASH RACK SIZING (Per USDCM, Volume 3)
Circular Pertoration Trash Rack Sizing
Required Open Area, At
At=0.5.����e o.,2ao))�Aot
46 square inches
Min. Distance between Columns, S� 3 inches
Width of Trash Rack and Concrete Opening per Column �4 inches
Use USDCM Volume 3, Table 6a-1
Total Width, W�o„�
Height of Trash Rack Screen, Htr
Type of Screen
Screen Opening Slot Dimension
Support Rod Type (See Table 6a-2)
Spacing of Support Rod (O.C.)
Total Screen Thickness (See Table 6a-2)
Carbon Steel Frame Type (See Table 6a-2)
Rectangular Pertoration Trash Rack Sizing (Not Used)
Required Open Area, At (including 50% clogging)
Ar=0.5 , ��� � e-a. i 2ao) �'Aot
Width of Trash Rack Opening, Wopening
Use USDCM Volume 3, Table 6b-1
Width of Concrete Opening, W�o��
Min Height of Trash Rack Screen, Ht, (including 2� a° below lowest openings)
Type of Screen
Screen Opening Slot Dimension
Minimum Bearing Bar Size (See Table 6b-2)
4 inches
13 3/16 inches Check - Larger than Required
S.S. #93 VEE Wire (US Filter)
0.139" (US Filter)
#156 VEE
3/4 inches O.C.
0.31 inches
3/8in x 1.Oin flat bar
0 square inches
�inches
12 inches
28.00 inches
Kelmp KRP Series Aluminum Bar Gate (or Equal)
3/16" Bars on 1-3/16" Centers
1 in x 3/16 in
21-1045-00 PondCalcs.xlsx Page 4 of 7 Highland Development Services
Heartside Hill
Critical Pond Elevations
Design Engineer: J.Claeys
Design Firm: Highland Development
Project Number: 21-1045-00
Date: May 10, 2023
DESIGN CRITERIA
Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, June 2001 (Revised January 2016)
Water Quality Capture Volume (WQCV):
Tributary Area, A 4.65 acres Basin D2 (not treated by LID)
Composite. Imperviousness, I
WQCV (watershed inches)
37.9%
0.174 inches
Required WQCV Volume =�wQZ V�* Area * 1.2 0.081 acre-feet
40-Hour Drain Time (Fig SQ-2)
Including 20% for Sedimentation
Stage Storage
Volume (pond volume calculated using the prismoidal formula):
V _ �A� + Az + A� Az �Depth
3
CONTOUR (FT) AREA (FTZ) AREA (ACRE) VOLUME DEPTH (FT) CUMULATIVE
ACRE-FT) VOLUME ACRE-FT
4907.75 0 0.000 0.000 0.00 0.000
4908.0 333 0.008 0.001 0.25 0.001
4908.5 4236 0.097 0.022 0.75 0.023
4909.0 10791 0.248 0.083 1.25 0.106
4909.5 15632 0.359 0.151 1.75 0.257
4910.0 17276 0.397 0.189 2.25 0.446
4910.5 18982 0.436 0.208 2.75 0.654
4911.0 21073 0.484 0.230 3.25 0.883
4911.5 23258 0.534 0.254 3.75 1.138
4912.0 0.000 0.089 4.25 1.227
Required Water Quality Capture Volume (WQCV) _
0.08 Acre-Ft Interpolates to an Elev. of
Required 100-yr Detention Volume (including WQCV) _
0.90 Acre-Ft Interpolates to an Elev. of
Provided Freeboard (33% Additional Volume) _
1.32 Acre-Ft Interpolates to an Elev. of
4908.85 ft
4911.03 ft
4911.86 ft
21-1045-00 PondCalcs.xlsx Page 5 of 7 Highland Development Services
Heartside Hill
Emergency Overflow Spillway Calculations
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: May 10, 2023
Broad-Crested Weir Equation-Trapezoidal Shape
; H s where: Q= Discharge (cfs)
0= CLH� +C�—�H� C= Weir Coeffecient
V L = Weir length (ft)
H = Average Weir Head (ft)
H:V =Side Slope
Calculations
Knowns: Side Slopes (H:V) 4.00
Desired Spillway Head 0.75 ft
Weir Coefficient 2.6
Spillway Elevation 4911.80 ft
100-yr Pond Inflow 58.88 cfs
Calculated Spillway 31.87 ft
Use Spillway Length 32 ft
Spillway Freeboard 0.00 ft
Total Spillway Depth 0.75 ft
Top of Berm Elevation 4912.55 ft
21-1045-00 PondCalcs.xlsx - Spillway Page 6 of 7 Highland Development Services
Heartside Hill
Circular Orifice Plate Sizing - Pond D
Design Engineer: J.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: May 10, 2023
Orifice Equation
Q = CAo �2gOh � A� _ �
" C 2goh where: C= Orifice Discharge Coefficient
A o = Orifice Area (ftZ)
D�, _
576A� g = Gravity (32.2 ft/s�)
n 4h = Difference in Elevation Head (ft)
D o = Orifice Diameter (in)
Calculations
100-yr Orifice Sizing
Knowns:
100-yr Release Rate 13.20 cfs
100-yr WSEL 4911.03 ft
Pond Outlet Invert 4907.25 ft
Discharge Coefficient 0.65
Tailwater Elevation 4908.13 ft
Orifice Diameter
Orifice Area
Centroid Elevation
Actual Release Rate
16 1/2 in
1.486 ft`
4907.94 ft
13.20 cfs
100-yr Orifice Rating Table
21-1045-00 PondCalcs.xlsx Page 7 of 7 Highland Development Services
APPENDIX D— LOW IMPACT DEVELOPMENT CALCULATIONS
Appendix D
Heartside Hili
Low Impact Development
Design Engineer: 1.Claeys
Design Firm: Highland Development Services
Project Number: 21-1045-00
Date: February 21, 2023
DESIGN CRITERIA
Urban Storm Drainage Criteria Manual by Urban Drainage and Flood Controi District, June 2001 (Revised lanuary 2016)
City of Fort Collins - Ordinance No. 007, 2016
- Treat at least 75% of any newly developed or redeveloped impervious area using one or a combination of LID techniques, or
- Treat at least 50% of any newly developed or redeveloped impervious area using one or a combination of LID techniques when 25% of private
driveable surfaces are permeable.
Low Impact Development Summary
Development Area Breakdown
Impervious Area % of Impervious Area Impervious Area
Description Sq-Ft Acres Requiring
(sq-ft) Requiring Treatment
Treatment
Existing Church Site 105,661 2.43 62,922 0% 0
Proposed Site 363,964 8.36 155,022 75% 116,266
Totals 443,462 10.78 217,943 - 116,266
LID Treatment Areas
Area Drainage Imperviaus WQ�ulz-n.
LID Contributing WQCVlZ.h, Treatment
Facility Basins to LID % Impervious Area Treated (Watershed inches) (cu-fc) Method
(sq-ft) (sq-fi) (includes 20% for sedimention)
OS1 OSl 88,538 65.4% 58,940 0.20 1,811 Rain Garden
D1 D1 163,080 39.8% 69,430 0.14 2,339 Rain Garden
Standard Water Quality Areas
Contributing Drainage Area Drainage Area a WQCV4o-n� WQ��ao-nr
EDB Pond / Impervious (ac-ft)
BdSInS (sq-ft) (acre) (watershed inches)
includes 20% for sedimention
Pond D D2 202,366 4.65 37.9% 0.17 0.081
LID Treatment Summary
Total Proposed Impervious Area 155,022
Total Impervious Area LID Treated (sq-ft) 128,370
Total % Impervious Area LID Treated 83%
Water Quality Area Treatment Summary
Description Area Area Treatment Ratio
s -ft acres
Total Area Treated by LID 251,618 5.78 53.6%
Total Area Treated by EDB 202,366 4.65 43.1%
Total Area Not Treated 15,641 0.36 3.3%
Total Improvement Area 469,625 10.78 100.0%
Design Procedure Form: Rain Garden (RG)
UD-BMP (Version 3.07, March 2018) Sheet 1 of 2
Designer: J.Claeys
Company: Highland Development Services
Date: February 21,2023
Project: Heartside Hill (Basin D1)
Location: Fort Collins, CO
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 39.8 %
(100 % if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = la/100) i= 0.398
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.14 watershed inches
(WQCV=0.8*(0.91*i3-1.19'iZ+0.78*i)
D) Contributing Watershed Area (including rain garden area) Area = 163,080 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQ�� =�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, VWocv ornEe = 1,949 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQcvuseR =�cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQ�� = 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 AM;,, = 1298 sq ft
D) Actual Flat Surface Area AA�„ai = 2373 sq ft
E) Area at Design Depth (Top Surface Area) AToP = 3454 sq ft
F) Rain Garden Total Volume VT= 2,914 cu ft
iVr= iiAroc + An�t„aJ / 2) * Depth)
Choose One
3. Growing Media Q 18" Rain Garden Growing Media
Q Other (Explain):
4. Underdrain System
Choose One
A) Are underdrains provided? OO YES
Q NO
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 Vol�2 =�cu ft
iii) Orifice Diameter, 3/8" Minimum Do =� in
21-1045-00 UD-BMP_v3.07 (Basin D1).xlsm, RG 2/21/2023, 10:55 AM
Design Procedure Form: Rain Garden (RG)
Sheet 2 of 2
Designer: J.Claeys
Company: Highland Development Services
Date: February 21, 2023
Project: Heartside Hill (Basin D1)
Location: Fort Collins, CO
5. Impermeable Geomembra�e Liner and Geotextile Separator Fabric Choose �ne
Q YES
A) Is an impermeable �iner provided due to proximity � NO
of structures or groundwater contamination?
6. Inlet / Outlet Control Choose One
Q Sheet Flow- No Energy Di55ipation Required
A) Inlet Control 0 Concentrated Flow- Energy Dissipation Provided
Choose One
7. Vegetation � Seed (Plan for frequent weed controi)
Q Plantings
0 Sand Grown or Other High Infiltration Sod
8. Irrigation Choose One
Q YES
A) Will the rain garden be irrigated? � NO
Notes:
21-1045-00 UD-BMP_v3.07 (Basin D1).xlsm, RG 2/21/2023, 10:55 AM
Design Procedure Form: Rain Garden (RG)
UD-BMP (Version 3.07, March 2018) Sheet 1 of 2
Designer: J.Claeys
Company: Highland Development Services
Date: February 21,2023
Project: Heartside Hill (Basin OS1)
Location: Fort Collins, CO
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 65.4 %
(100 % if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = la/100) i= 0.654
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.20 watershed inches
(WQCV=0.8*(0.91*i3-1.19'iZ+0.78*i)
D) Contributing Watershed Area (including rain garden area) Area = 88,538 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQ�� =�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, VWocvornEe = 1,509 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQcvuseR =�cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQ�� = 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 AM;,, = 1158 sq ft
D) Actual Flat Surface Area AA�t„ai = 1453 sq ft
E) Area at Design Depth (Top Surface Area) AToP = 2236 sq ft
F) Rain Garden Total Volume VT= 1,845 cu ft
iVr= iiAroc + An�t„aJ / 2) * Depth)
Choose One
3. Growing Media Q 18" Rain Garden Growing Media
Q Other (Explain):
4. Underdrain System
Choose One
A) Are underdrains provided? OO YES
Q NO
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 Vol�2 =�cu ft
iii) Orifice Diameter, 3/8" Minimum Do =� in
21-1045-00 UD-BMP_v3.07 (Basin OS1).xlsm, RG 2/21/2023, 12:21 PM
Design Procedure Form: Rain Garden (RG)
Sheet 2 of 2
Designer: J.Claeys
Company: Highland Development Services
Date: February 21, 2023
Project: Heartside Hill (Basin OS1)
Location: Fort Collins, CO
5. Impermeable Geomembra�e Liner and Geotextile Separator Fabric Choose �ne
Q YES
A) Is an impermeable �iner provided due to proximity � NO
of structures or groundwater contamination?
6. Inlet / Outlet Control Choose One
Q Sheet Flow- No Energy Di55ipation Required
A) Inlet Control 0 Concentrated Flow- Energy Dissipation Provided
Choose One
7. Vegetation � Seed (Plan for frequent weed controi)
Q Plantings
0 Sand Grown or Other High Infiltration Sod
8. Irrigation Choose One
Q YES
A) Will the rain garden be irrigated? � NO
Notes:
21-1045-00 UD-BMP_v3.07 (Basin OS1).xlsm, RG 2/21/2023, 12:21 PM
APPENDIX E— INLET, PIPE, & SWALE CAPACITY CALCULATIONS
Appendix E
Heartside Hill
TYPE C AREA WLET SIZING CALCULATION
Design Engineer:
Design Firm:
Project Number:
Date:
DESIGN CRITERIA
1.Claeys
Highland Development Services
21-1045-00
February 22, 2023
EQUATIONS:
Q; = Grate Capacity w/o Reduction Factor (cfs)
C= Orifice Discharge Coefficient = 0.67
Qi = CA 2gH A= Orifice area (ft�) - Open Area of Grate
G = Gravitational Constant (32.2 ft/sz)
H= Allowed Head on Grate, Ponding Depth (ft)
Apply Reduction Factor for the Allowable Capacity.
Qc = Qi�1 - F)
Grate Dimensions and Information:
Width ( W ): 3 ft
Length (L ): 3 ft
Opening Ratio (R ): 0.65 sqft/sqft
Reduction Factor (F): 50%
Inlet Grate Open Area (A ): 5.85 sqft
Assumed Capacity per Head Allowed
Inlet Inlet Capacity
Capacity w/ Reduction
A�lowed Head (ft) (Q;, cfs) Factor (Q�, cfs)
0.25 15.73 7.86
0.50 22.24 11.12
1.00 31.45 15.73
1.50 38.52 19.26
2.00 44.48 22.24
INLET SIZING CALCULATIONS
:►'���``��`���
•:���`���`��`������
�`��`�``�����
•/
��
I
[1I
(
L H
_ �
Design Flow Design
Rate Allowed Head Inlet Capacity Flow Depth
Inlet ID: (Q,00. cfs): (H, ft�: (C�, cfs) (H, ft)
Inlet-D2a 5.64 1.5 19.26 0.13
Inlet-D2b 10.65 1.2 17.23 0.46
Outlet-DOl 13.20 2.17 23.17 0.70
Outlet-O51 16.14 0.25 7.86 1.05
Page1
Weir Report
Hydraflow Express Extension for AutodeskOO Civil 3DOO by Autodesk, Inc.
Inlet-D2c Capacity
Rectangular Weir
Crest = Sharp
Bottom Length (ft) = 15.00
Total Depth (ft) = 0.50
Calculations
Weir Coeff. Cw = 3.33
Compute by: Q vs Depth
No.lncrements = 10
Depth (ft)
1.00
0.50
� ��
-0.50
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Top Width (ft)
Inlet-D2c Capacity
Tuesday, May 9 2023
= 0.45
= 15.08
= 6.75
= 2.23
= 15.00
Depth (ft)
1.00
0.50
� ��
-0.50
0 2 4 6 8 10 12 14 16 18 20
Weir w.S. Length (ft)
� Sewers Extension for Autodesk0 Civil 3D0 Plan
' Outfall
Outfall
7
SDMH-02
OUTLET-D01
�D2a 3
Outfall
INLET-D2c 4
�♦ ��u�fall
�
Inlet-D2b
Number of lines: 8 I Date: 5/9/2023
Storm Sewers v2023.00
Page 1
�rt Invert Line Line HGL HGL HGL EGL EGL EGL Gnd/Rim Gnd/Rim Junct Vel
� Dn Length Slope Up Dn Jnct Up Dn Jnct EI Up EI Dn Type Ave
) (ft) (ft) (%) (ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft/s)
13 4926.01 12.059 1.00 4926.99 4927.43 4926.99 4927.35 4927.79 4927.35 4930.03 4927.81 MH 3.85
55 4926.13 42.009 1.00 4927.44 4926.99 4927.44 4927.82 4927.37 4927.82 4929.50 4930.03 Grate 5.02
76 4923.14 86.000 0.72 4924.68 j 4924.06 4924.68 4925.06 4924.45 4925.06 4926.47 4924.93 Grate 4.98
87 4909.17 33.000 5.15 4912.25 4910.54 4912.25 4912.87 4911.16 4912.87 4913.73 4911.51 Generic 6.34
72 4909.20 34.504 1.51 4910.97 4910.45 4910.97 4911.68 4911.16 4911.68 4912.43 4910.99 Grate 6.76
00 4906.85 15.086 0.99 4908.35 4908.20 4908.35 4909.03 4908.88 4909.03 4910.90 0.00 MH 6.63
19 4907.00 113.000 0.17 4909.42 4908.75 4909.70 4909.89 4909.22 4910.17 4911.96 4910.90 MH 5.49
25 4907.19 32.694 0.18 4909.89 4909.70 4910.36 4910.36 4910.17 4910.83 4909.85 4911.96 Grate 5.49
Number of lines: 8 I Date: 5/9/2023
Storm Sewers
�file
Proj. file: New.stm
G�;y�1I111
20 30 40 50 60 70 80 90 100 110 120 130 140
EGL Reach (ft)
4917.00
4914.00
4911.00
4908.00
, ,•� ��
Storm Sewers
�
� � �
� O� � O
� �O rn rn . �+"� u�
�file
Proj. file: New.stm
M 7
C �
� n co
EGL Reach (ft)
�:xi:�r�i��
4933.00
4930.00
4927.00
4924.00
4921.00
Storm Sewers
) 20 30 40 50 60 70 80 90 100
�file
Proj. file: New.stm
�
� �
O� � O
�MM . Olf]
EGL Reach (ft)
�:xx�r�i��
4935.00
4932.00
4929.00
4926.00
4923.00
Storm Sewers
) 20 30 40 50 60 70 80 90 100
�file
Proj. file: New.stm
�
�
= o
� mN
EGL Reach (ft)
C�;y��iI�l
4919.00
4916.00
4913.00
4910.00
4907.00
Storm Sewers
) 20 30 40 50 60 70 80 90 100
�file
Proj. file: New.stm
v �
� O
J M�
EGL Reach (ft)
C�;3►�:�iI�l
4922.00
4918.00
4914.00
4910.00
4906.00
Storm Sewers
) 20 30 40 50 60 70 80 90 100
Channel Report
Hydraflow Express Extension for AutodeskOO Civil 3DOO by Autodesk, Inc.
West Culverts
Circular
Diameter (ft)
= 1.25
Invert Elev (ft)
Slope (%)
N-Value
Calculations
Compute by:
No. Increments
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
= 100.00
= 2.00
= 0.016
Q vs Depth
= 10
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Section
Reach (ft)
Wednesday, Feb 15 2023
= 1.13
= 7.910
= 1.16
= 6.80
= 3.13
= 1.12
= 0.75
= 1.84
0 1 2 3
Channel Report
Hydraflow Express Extension for AutodeskOO Civil 3DOO by Autodesk, Inc.
Inlet-D2b Pipe & East Culverts
Circular
Diameter (ft)
= 1.50
Invert Elev (ft)
Slope (%)
N-Value
Calculations
Compute by:
No. Increments
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
= 100.00
= 1.50
= 0.016
Q vs Depth
= 10
Monday, Feb 20 2023
�xceeds 'Peak 100-yr
Highlighted
Depth (ft) 1.35
Q (cfs) = 11.14
Area (sqft) = 1.68
Velocity (ft/s) = 6.65
Wetted Perim (ft) = 3.75
Crit Depth, Yc (ft) = 1.28
Top Width (ft) = 0.90
EGL (ft) = 2.04
Section
Reach (ft)
0 1 2 3
Channel Report
Hydraflow Express Extension for AutodeskOO Civil 3DOO by Autodesk, Inc.
Basin D2a & Basin D2b Swale
Triangular
Side Slopes (z:1) = 4.00, 4.00
Total Depth (ft) = 2.50
Invert Elev (ft) = 100.00
Slope (%) = 1.77
N-Value = 0.030
Calculations
Compute by: Q vs Depth
No.lncrements = 10
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Wliwivna►m Swale Slo�e
Wednesday, Feb 22 2023
= 1.50
= 47.97
= 9.00
= 5.33
= 12.37
= 1.55
= 12.00
= 1.94
Elev (ft) Section
103.00
102.50
102.00
101.50
101.00
100.50
100.00
99.50
Depth (ft)
3.00
2.50
2.00
1.50
1.00
� �
� ��
_n �n
I 2 4 6 8 10 12 14 16 18 20 22 24 v
Reach (ft)
Channel Report
Hydraflow Express Extension for AutodeskOO Civil 3DOO by Autodesk, Inc.
OS1 - Offsite Spread for Easement
Gutter
Cross SI, Sx (ft/ft) = 0.020
Cross SI, Sw (ft/ft) = 0.083
Gutter Width (ft) = 2.00
Invert Elev (ft) = 100.00
Slope (%) = 2.25
N-Value = 0.016
Calculations
Compute by: Known Q
Known Q (cfs) = 15.84
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Spread Width (ft)
EGL (ft)
Wednesday, Aug 16 2023
= 0.46
= 15.84
= 2.97
= 5.33
= 17.34
= 0.60
= 16.87
= 0.91
Elev (ft) Section
101.00
100.75
100.50
100.25
100.00
99.75
Depth (ft)
1.00
0.75
0.50
0.25
� ��
_n ��
) 2 4 6 8 10 12 14 16 18 20 22 24 v
Reach (ft)