HomeMy WebLinkAboutHOME2 SUITES AT HARMONY VILLAGE - PDP - PDP150031 - REPORTS - DRAINAGE REPORTPDP DRAINAGE REPORT
FOR
HOME2 SUITES
AT HARMONY VILLAGE
Prepared For:
East Avenue Development LLC
1001 Cypress Creek Road #203
Cedar Park, TX 78613
January 20, 2016
Project No. 39705.01
Prepared By:
JR Engineering, LLC
2900 South College Avenue, Suite 3D
Fort Collins, CO 80525
Page i
TABLE OF CONTENTS
Table of Contents ............................................................................................................................................... i
Vicinity Map ......................................................................................................................................................... 1
General Description and Location .................................................................................................................. 2
Location And Existing Site Characteristics ................................................................................................. 2
Site Soils ........................................................................................................................................................... 2
Floodplain ........................................................................................................................................................ 2
Drainage Basins and Sub-Basins ....................................................................................................................... 3
Major Basin ...................................................................................................................................................... 3
Historic Sub-Basins ........................................................................................................................................ 3
Developed Sub-Basins.................................................................................................................................... 4
Drainage Design Criteria .................................................................................................................................. 5
Regulations ...................................................................................................................................................... 5
Low-Impact Development ............................................................................................................................ 5
Hydrologic Criteria ........................................................................................................................................ 5
Hydraulic Criteria........................................................................................................................................... 6
Drainage Facility Design .................................................................................................................................... 7
General Concept ............................................................................................................................................ 7
Water Quality/ Detention Facilities ............................................................................................................ 7
Stormwater Pollution Prevention .................................................................................................................... 8
Temporary Erosion Control ........................................................................................................................ 8
Permanent Erosion Control ......................................................................................................................... 8
Summary & Conclusions ................................................................................................................................... 8
References ........................................................................................................................................................... 9
APPENDIX
Appendix A – Site & Soil Descriptions and Characteristics
Appendix B – Hydrologic Calculations
Appendix C – Hydraulic Calculations
Appendix D – Existing & Proposed Drainage Plans
Appendix E – LID Exhibit
Page ii
Engineer’s Certification Block
I hereby certify that this Project Development Plan Drainage Report for Home2 Suites at Harmony
Village was prepared by me (or under my direct supervision) for JR Engineering, LLC and the
owners thereof and meets or exceeds the criteria of the City of Fort Collins Stormwater Design
Standards.
________________________________________
Timothy J. Halopoff, PE
Registered Professional Engineer
State of Colorado No. 37953
Page 1
VICINITY MAP
Page 2
GENERAL DESCRIPTION AND LOCATION
LOCATION AND EXISTING SITE CHARACTERISTICS
The proposed Home2 Suites at Harmony Village is located in the northeast one-quarter of Section
6, Township 6 North, Range 68 West of the 6th Principal Meridian in the City of Fort Collins,
Larimer County, Colorado. More specifically, the Home2 Suites site is a 1.85 acre property that is
currently partially undeveloped with an existing 96 space parking lot. The site is bounded by Texas
Roadhouse on the north, Delany Drive on the east, shopping centers to the west, and Cinemark
Theater to the south. The site is zoned HC – Harmony Corridor and will support the proposed
hotel and associated parking requirements. The proposed use of the site is a 4 story extended stay
hotel.
The existing site generally slopes from the northwest to southeast with slopes ranging between 1%
and 2.0%. Undeveloped portions of the property are generally covered with sparse native grasses.
The western half of the site currently drains to the south lot line where runoff is collected in an
existing sump area before exiting onto existing parking lots, both east and west of the Cinemark
Theater. No existing storm infrastructure exists. All surface runoff infiltrates or exits the site via
overland flow in the parking lots to the south and southeast. Due to the existing topography of the
vacant land, the existing facilities allow standing water without treatment or a sufficient path for
exiting the site without encroachment on to the Cinemark property. Special considerations are
being taken to ensure the current situation is improved to provide better conveyance away from
the Cinemark property.
SITE SOILS
The Home2 Suites at Harmony Village site soils consist of loamy soil, predominately Nunn clay
loam. Nunn clay loam belongs to hydrologic soils Group C. Group C soils have 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. Nunn clay loam with 0-3 percent slopes generally has a combined surface
layer thickness of approx. 30 inches. Runoff is moderately high, and the hazards of wind erosion
are moderately low. Supporting figures can be found in the Appendix, page A-1.
FLOODPLAIN
The site is shown on FEMA FIRM panel 08069C1000F, eff. December 19, 2006. The site lies within
an area determined to be outside the 100yr floodplain, and in an area of minimal flood hazard. The
“City of Fort Collins Floodplain Review Checklist for 50% Submittals” checklist is not applicable for
this PDP Drainage Report.
Page 3
DRAINAGE BASINS AND SUB-BASINS
MAJOR BASIN
The proposed Home2 Suites at Harmony Village site is located in the McClellands Drainage Basin.
The master study for this area is the “McClellands Basin Master Drainage Plan” by Greenhorn and
O’Mara, Inc., 1986. Harmony Village is sub-basin 301 and the detention pond associated with
Harmony Village P.U.D. is conveyance element 301 of the most recent SWMM model for the
McClellands Basin, dated July 1997. The majority of the Harmony Village P.U.D basin is developed
and includes commercial and residential uses. Detention for the site is provided within the existing
regional detention Pond A, located in the southeast corner of the Harmony Village Site
There are no major drainageways located within or immediately adjacent to the site. The site is
shown on FEMA FIRM panel 08069C1000F, eff. December 19, 2006. An annotated FIRM exhibit is
included in Appendix A-2.
HISTORIC SUB-BASINS
Home2 Suites at Harmony Village is an infill development. It is governed by the City’s Reasonable
Use policy, in which the proposed drainage basins will need to follow the generally accepted
principle. Note: The release rate for the regional detention pond was limited to 0.5 cfs/acre for the
100-year event and 0.2 cfs/acre for the 10-year event in accordance with the “McClellands Basin
Master Drainage Plan”. Therefore, historic (existing) runoff calculations are included solely as
reference in this report. There are no substantial offsite areas that flow across the proposed
development site. Referring to the “Existing Drainage Plan”, included in Appendix D, the following
describes the existing condition drainage basins.
Existing Onsite Sub-Basins:
The site has two existing drainage basins.
Sub-basin EX1 consists of a 1.67 acre area. The western half of Basin EX1 is undeveloped
open space with native grasses and weeds covering the majority of the ground and is
assumed to be 5% impervious. The eastern half of this basin is an existing asphalt parking
lot and is assumed to be 100% impervious. Runoff generally flows to the southeast across
basin EX-1, at slopes ranging from 0.50% to 2.0%, generally leaving the site at the southeast
corner, where it is enters the right-of-way of Delany Drive. This basin also includes runoff
from the Cinemark Theater property crossing onto the southern boundary of the
Home2 Suites site. Currently this runoff pools in an existing sump area before overtopping
into the existing parking lot to the east. Adding to this poor drainage situation, the sidewalk
and landscaping areas along the north end of the theater hardly drain to away from the
building foundation.
Page 4
Sub-basin EX2 consists of a 0.28 acre area of undeveloped open space with the same
ground cover and percentage imperviousness as sub-basin EX-1. Runoff in sub-basin EX-1
collects in an existing sump area north of the Cinemark Theater. Overflow from the sump
area flows south to the southwest corner of the site where it conveyed off-site into an
existing parking lot.
DEVELOPED SUB-BASINS
The proposed developed condition sub-basins have been designed to mimic the historic basins’
runoff patterns. The following describes the proposed conditions on-site drainage basins. Refer to
the “Proposed Drainage Plan” in Appendix D for review.
Proposed Onsite Sub-Basins:
Sub-basin A1 consists of 0.41 acres on the northwest portion of the subject property.
Runoff from the proposed drive lanes and parking lot travels west and south to an proposed
bioretention basin along the southern property line. From the bioretention basin (Basin A2),
runoff flows east in a bioswale through another bioretention basin (Basin A3) and into the
existing parking lot on the southern edge of the property.
Sub-basin A2 consists of 0.31 acres on the southwest corner of the subject property.
Runoff from this sub-basin, primarily the roof, is collected in a bioretention basin composing
the southern half of this basin. From the bioretention basin, runoff flows south in a bioswale
through another bioretention basin (Basin A3) and into the exiting parking lot on the
southern edge of the property.
Sub-basin A3 consists of 0.37 acres on the south central of the subject property. Runoff
from this sub-basin, primarily the roof, is collected in a bioretention basin composing the
southern half of this basin. From the bioretention basin, runoff flows into the exiting parking
lot on the southern edge of the property.
Sub-basin B1 consists of 0.12 acres near the northern boundary of the subject property.
Runoff from the proposed northern patio and drive lane travels east through pervious
pavers on the northern edge of the property. From the previous pavers, runoff continues
sheet flowing east through the existing parking lot and into sub-basin B2.
Sub-basin B2 consists of 0.88 acres on the eastern half of the subject property. Runoff
from the building entrance is captured in pervious pavers, and joins with runoff from
sub-basin B2, continuing to flow east through the existing parking lot to the eastern edge of
the property into Delany Drive.
Page 5
Sub-basin C2 consists of 0.02 acres in the western portion of the subject property.
Runoff from the proposed landscaping area is conveyed to an existing parking lot paralleling
the western site boundary. This runoff is deemed nuisance flow and therefore considered
negligible.
DRAINAGE DESIGN CRITERIA
REGULATIONS
This report was prepared to meet or exceed the City of Fort Collins stormwater criteria. The City
of Fort Collins Storm Drainage Design Criteria and Construction Manual (with all current 2011
Revisions)(FCSDDCCM) 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.
LOW-IMPACT DEVELOPMENT
Volume reduction is an important part of the Four Step Process and is fundamental to effective
stormwater management. Per City criteria, a minimum of 50 percent of new impervious surface
area must be treated by a Low-Impact Development (LID) best management practice (BMP). 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 improvements will decrease the runoff coefficient from the site and are expected to
have no adverse impact on the timing, quantity, or quality of stormwater runoff. Site-specific LID
BMPs are discussed in the following sections of this report and an illustrative LID/Surface map is
provided in Appendix E. In summary, the site is treating approximately 98% of the new impervious
area with a variety of LID measures.
HYDROLOGIC CRITERIA
The rational method was performed to calculate the peak runoff rates for each basin. Weighted
percent imperviousness and weighted runoff coefficients were calculated for each basin using
USDCM Table 6-3, in addition to Table RO-11–Rational Method Runoff Coefficients for Composite
Analysis (City of Fort Collins), based on Natural Resources Conservation Service (NRCS) Type C
hydrologic soil classification and surface characteristics of each basin. The time of concentration was
calculated using USDCM Equation RO-3 and the intensity was calculated using the corresponding
storm rainfall depth and Intensity-Duration-Frequency Curves for Rational Method (Table RA-7 –
City of Fort Collins). The City of Fort Collins area has 2-year, 1-hour rainfall depth of 0.82 inches
and a 100-year, 1- hour rainfall depth of 2.86 inches.
Page 6
HYDRAULIC CRITERIA
This report demonstrates that the proposed stormwater concept is in compliance with the
100-year developed runoff condition planned for Lot 11A within the Master report. Basins 101 and
114 from the master report have runoff coefficients of 0.89 and 1.0, respectively. The proposed
improvements have a maximum runoff coefficient of 0.90 with the majority of the site having a
significantly lower coefficient and corresponding runoff. The Rational Method was used to
determine both 2-year and 100-year peak runoff values for each sub-basin. Runoff coefficients were
assigned using Table 3-2 of the SDDCCS Manual. The Rational Method is
based on the Rational Formula,
Q = CfCIA (1)
where Q is the maximum rate of runoff in cfs, A is the total area of the basin in acres, Cf is the
storm frequency adjustment factor, C is the runoff coefficient, and I is the rainfall intensity in inches
per hour for a storm duration equal to the time of concentration. The frequency adjustment
factor, Cf, is 1.0 for the initial 2-year storm and 1.25 for the major 100-year storm. The runoff
coefficient is dependent on land use or surface characteristics.
The rainfall intensity is selected from Rainfall Intensity Duration Curves for the City of Fort Collins
(Figure 3.1 of SDDCCS). In order to utilize the Rainfall Intensity Duration Curves, the time of
concentration is required. The following equation is used to determine the time of concentration
tc = ti + tt (2)
where tc is the time of concentration in minutes, ti is the initial or overland flow time in minutes,
and tt is the travel time in the ditch, channel, or gutter in minutes. The initial or overland flow time
is calculated with the SDDCCS Manual equation:
ti = [1.87(1.1 - CCf)L0.5]/(S)0.33 (3)
where L is the length of overland flow in feet (limited to a maximum of 500 feet), S is the average
slope of the basin in percent, and C and Cf are as defined previously.
All hydrologic calculations associated with the sub-basins shown on the attached drainage plan are
included in Appendix B of this report.
The Home2 Suites at Harmony Village surface drainage system will be designed to convey the
minor and major storm events through the property with the curb and gutter, soft swales, and LID
measures for the flows being calculated by this report. Per the requirements provided by the City
of Fort Collins Storm Drainage Design Criteria and Construction Manual, conveyance elements will
be designed to convey the 100-year storm flows. During the major developed condition 100-year
storm, the accumulated water depth in the ponds will be held to a maximum level of one-foot
below all building finished floor elevations. Additionally, this report dictates that no changes are
expected to the offsite conditions or flows. The improvements with this proposed site are in
conformance with the Harmony Village master study drainage assumptions.
Page 7
All swale outlets will be protected with turf mat or riprap; whichever is most appropriate. Lid
measures have been integrated into this design on higher levels than most City of Fort Collin’s
projects to date. In all, 98% of this project’s impervious areas pass through and are treated in LID’s
prior to reaching their historic outfall locations.
DRAINAGE FACILITY DESIGN
GENERAL CONCEPT
The proposed improvements to the Home2 Suites at Harmony Village site will result in developed
condition runoff being conveyed around the proposed buildings and to the southeast via curb and
gutter and sheet flow across paving. Low-impact development best management practices are
proposed to improve the quality of runoff and aid in reducing peak flows. Specifically, permeable
pavement systems are proposed for portions of the drive lanes along the northern property line
and near the eastern entrance. The permeable pavement systems will not include underdrains
because no storm sewer systems exist in the area to accommodate system outfall. Two
bioretention basins and one bioswale are proposed on the southern side of the site to improve
storm runoff water quality. The western bioretention basin will include an underdrain that will
outfall into the eastern bioretention basin. The bioswale will provide overflow conveyance from the
western to eastern basin. The east basin will incorporate a rock infiltration gallery to increase soil
absorption rates of detained runoff. The rock gallery is proposed because an underdrain cannot be
provided since no storm sewers exist in the area. Large runoff events will overtop the eastern basin
and flow into the parking lot to the east.
WATER QUALITY/ DETENTION FACILITIES
Water quality will be provided for the site through the use of the bioretention basins and the
bioswale. The total required water quality volume for our proposed site it 0.03 ac-ft. Detention
will be provided for the site through the existing regional detention Pond A in the southeast corner
of the Harmony Village site. The proposed bioretention basins will retain minor storm runoff from
the site and release the major storm runoff to the regional detention facility.
Page 8
STORMWATER POLLUTION PREVENTION
TEMPORARY EROSION CONTROL
A temporary erosion control plan is to be implemented for the site during construction.
Temporary erosion control measures include, but are not limited to, slope and swale protection,
silt fence placed around downstream areas of disturbance, construction vehicle tracking pad at
entrances, a designated concrete truck washout basin, designated vehicle fueling areas, inlet
protection, and others. All temporary erosion control measures are to be removed after they are
deemed unnecessary.
PERMANENT EROSION CONTROL
Permanent erosion control measures include, but are not limited to, the constructed LID basins,
boulder linking placed for overflow protection, seeding and mulch placed to enable and established
vegetative growth, etc. Long-term maintenance of these erosion control measures shall be the
responsibility of the owner of the property. JR will provide a detailed Storm Water Management
and Erosion Control Plan at the time of the FDP submittal that will meet all requirements of the
City of Fort Collins.
SUMMARY & CONCLUSIONS
The existing conditions drainage has two onsite sub-basins with nearby outfall points along the
southern boundary of the subject property. The proposed drainage condition was designed to
mimic the historic basins’ runoff patterns. The existing conditions drainage patterns are maintained
in the design of the project. The proposed improvements will have positive impacts on the timing,
flow rate, and quality of runoff leaving the site; and will reduce potential impacts for minor storm
flooding downstream of this site.
The hydrologic and LID calculations were performed using the required methods as outlined in the
City of Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria
Manual. The proposed drainage improvements meet or exceed the City’s requirements. This PDP
Drainage Report and the complimenting drainage plans and LID plans propose appropriate grading,
permanent landscaping, LID BMPs, and onsite facilities (e.g. pervious paver, lid basins, etc.) that are
shown in their preliminary configuration and will be designed for construction in the Final Drainage
Report along with supporting calculations.
The proposed concept for the development of the Home2 Suites at Harmony Village site involves
routing developed condition flows to proposed onsite LID basins. LID site enhancements will treat
the site runoff at the source before allowing the runoff to be conveyed to the existing outfall points
in the parking lot. The site’s stormwater surface facilities are sized to meet the City of Fort Collins
“Storm Drainage Criteria Manual and Construction Standards”.
Page 9
REFERENCES
1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood
Control District, Updated November 2010.
2. Storm Drainage Criteria Manual and Construction Standards, City of Fort Collins Storm Water
Utility, City of Fort Collins, Colorado, Updated February, 2013.
3. “Hydrologic Group Rating for Larimer County Area, Colorado”, USDA-Natural Resources
Conservation Service, National Cooperative Soil Survey. Web Soil Survey URL:
http://websoilsurvey.nrcs.usda.gov. [Sept 25, 2010]
4. Final Drainage and Erosion Control Report for Harmony Village P.U.D., prepared by JR
Engineering, Ltd., Updated September, 2014.
APPENDIX A
SITE & SOIL DESCRIPTIONS AND CHARACTERISTICS
HOME2 SUITES HARMONY VILLAGE DRAINAGE REPORT
Project No. 39705.01 FIGURE 3 - FIRM MAP
APPENDIX B
HYDROLOGIC CALCULATIONS
Subdivision: Harmony Village Project Name: Home2Suites
Location: Fort Collins Project No.:
Calculated By: DRC
Checked By: 0
Date: 1/18/16
FINAL
BASIN D.A. Hydrologic Impervious C100 C
2 L S Ti
L S Cv VEL. Tt COMP. T
c TOTAL Urbanized Tc
Tc
ID (AC) Soils Group (%) (FT) (%) (MIN) (FT) (%) (FPS) (MIN) (MIN) LENGTH(FT) (MIN) (MIN)
EX1 1.67 C 59.0 0.74 0.59 180 0.1 27.0 260 0.6 20.0 1.5 2.8 29.8 440.0 12.4 12.4
EX2 0.28 C 5.0 0.25 0.20 40 0.5 13.1 60 0.5 5.0 0.4 2.8 16.0 100.0 10.6 10.6
NOTES:
Ti = (0.395*(1.1 - C
5)*(L)^0.5)/((S)^0.33), S in ft/ft
Tt=L/60V (Velocity From Fig. 501)
Velocity V=Cv*S^0.5, S in ft/ft
Tc Check = 10+L/180
For Urbanized basins a minimum Tc of 5.0 minutes is required.
For non-urbanized basins a minimum Tc of 10.0 minutes is required
Cv
2.5
5
7
10
15
20
(URBANIZED BASINS)
Type of Land Surface
STANDARD FORM SF-2
EXISTING TIME OF CONCENTRATION
39705.01
SUB-BASIN INITIAL/OVERLAND TRAVEL TIME Tc CHECK
(Ti) (T
t)
Tillage/field
Short pasture and lawns
Nearly bare ground
Grassed waterway
Paved areas and shallow paved swales
DATA
Heavy Meadow
\\dn-nfs-02\projects\3970000.all\3970501\Excel\Drainage\3970501Drainage_Calcs.xls Page 1 of 1 1/18/2016
Subdivision: Harmony Village Project Name: Home2Suites
Location: Fort Collins Project No.:
Calculated By: DRC
Checked By: 0
Date:
A1 0.41 100 0.36 87.80 5 0.05 0.60 90 0.00 0.00 88.40
A2 0.31 100 0.03 9.68 5 0.11 1.80 90 0.17 49.40 60.88
A3 0.37 100 0.11 29.73 5 0.02 0.30 90 0.24 58.40 88.43
B1 0.12 100 0.09 75.00 5 0.03 1.30 90 0.00 0.00 76.30
B2 0.88 100 0.83 94.32 5 0.05 0.30 90 0.00 0.00 94.62
C1 0.02 100 0.00 0.00 5 0.02 5.00 90 0.00 0.00 5.00
Site 2.11 85.5
A1 0.41 0.95 0.36 0.83 0.20 0.05 0.00 0.95 0.00 0.00 0.83
A2 0.31 0.95 0.03 0.09 0.20 0.11 0.10 0.95 0.17 0.50 0.69
A3 0.37 0.95 0.11 0.28 0.20 0.02 0.00 0.95 0.24 0.60 0.88
B1 0.12 0.95 0.09 0.71 0.20 0.03 0.10 0.95 0.00 0.00 0.81
B2 0.88 0.95 0.83 0.90 0.20 0.05 0.00 0.95 0.00 0.00 0.90
C1 0.02 0.95 0.00 0.00 0.20 0.02 0.20 0.95 0.00 0.00 0.20
Area (ac) Weighted
Coeff.
Pavement & Sidewalk Lawns Roofs
Basins Total Weighted Runoff
Basin ID Total Area (ac) Runoff Coeff. Area (ac) Coeff. (2-yr)
Weighted
Coeff. Runoff Coeff. Area (ac)
Weighted
Coeff. Runoff Coeff.
COMPOSITE % IMPERVIOUS & WEIGHTED RUNOFF COEFF. CALCULATIONS
39705.01
1/18/16
% Imp. Area (ac) Weighted
% Imp. % Imp.
Pavement & Sidewalk Lawns Roofs
Area (ac) Weighted
% Imp.
Basin ID Total Area (ac) % Imp. Area (ac) Basins Total Weighted % Imp.
Weighted
% Imp.
X:\3970000.all\3970501\Excel\Drainage\3970501Drainage_Calcs.xls Page 1 of 1 1/19/2016
Subdivision: Harmony Village Project Name: Home2Suites
Location: Fort Collins Project No.:
Calculated By: DRC
Checked By: 0
Date: 1/18/16
FINAL
BASIN D.A. Hydrologic Impervious C100 C
2 L S Ti
L S Cv VEL. Tt COMP. T
c TOTAL Urbanized Tc
Tc
ID (AC) Soils Group (%) (FT) (%) (MIN) (FT) (%) (FPS) (MIN) (MIN) LENGTH(FT) (MIN) (MIN)
A1 0.41 C 88.4 1.00 0.83 10 2.0 1.2 145 0.5 20.0 1.4 1.7 2.9 155.0 10.9 5.0
A2 0.31 C 60.9 0.86 0.69 60 5.0 3.4 85 1.0 15.0 1.5 0.9 4.3 145.0 10.8 5.0
A3 0.37 C 88.4 1.00 0.88 60 5.0 1.8 100 0.6 15.0 1.2 1.4 3.3 160.0 10.9 5.0
B1 0.12 C 76.3 1.00 0.81 5 2.0 0.9 120 0.5 20.0 1.4 1.4 2.4 125.0 10.7 5.0
B2 0.88 C 94.6 1.00 0.90 150 1.0 4.5 175 0.8 20.0 1.7 1.7 6.2 325.0 11.8 6.2
C1 0.02 C 5.0 0.25 0.20 5 10.0 1.7 5 10.0 15.0 4.7 0.0 1.7 10.0 10.1 5.0
NOTES:
Ti = (0.395*(1.1 - C
5)*(L)^0.5)/((S)^0.33), S in ft/ft
Tt=L/60V (Velocity From Fig. 501)
Velocity V=Cv*S^0.5, S in ft/ft
Tc Check = 10+L/180
For Urbanized basins a minimum Tc of 5.0 minutes is required.
For non-urbanized basins a minimum Tc of 10.0 minutes is required
Cv
2.5
5
7
10
15
20
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN Tc CHECK
39705.01
DATA (URBANIZED BASINS)
INITIAL/OVERLAND
(Ti)
Grassed waterway
TRAVEL TIME
(Tt)
Paved areas and shallow paved swales
Type of Land Surface
Heavy Meadow
Tillage/field
Short pasture and lawns
Nearly bare ground
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APPENDIX C
HYDRAULIC CALCULATIONS
Project Name: Home2Suites
Subdivision: Harmony Village Project No.:
Location: Fort Collins Calculated By: DRC
Design Storm: Checked By: 0
Date: 1/18/16
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
Existing 2-yr Flows
EX1 EX1 1.67 0.59 12.4 0.99 2.05 2.0
EX2 0.28 0.20 10.6 0.06 2.21 0.1 12.4 1.05 2.05 2.2
Existing 100-yr Flows
EX1 EX1 1.67 0.74 12.4 1.23 7.16 8.8
EX2 0.28 0.25 10.6 0.07 7.72 0.5 12.4 1.30 7.16 9.3
STANDARD FORM SF-3
EXISTING STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
39705.01
2-Year
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
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Project Name: Home2Suites
Subdivision: Harmony Village Project No.:
Location: Fort Collins Calculated By: DRC
Design Storm: Checked By: 0
Date: 1/18/16
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
Flow passing over pavers
through chase drain into LID 1 A1 0.41 0.83 5.0 0.34 2.85 1.0 0.5
Total flows entering LID #1 2 A2 0.31 0.69 5.0 0.21 2.85 0.6 5.0 0.55 2.85 1.6 0.6
Total flows entering LID #2 3 A3 0.37 0.88 5.0 0.33 2.85 0.9 5.0 0.88 2.85 2.5
Flow passing over Paver Section #1 4 B1 0.12 0.81 5.0 0.10 2.85 0.3 0.5
Flow exiting off-site to Delany Drive 5 B2 0.88 0.90 6.2 0.79 2.67 2.1 6.2 0.89 2.67 2.4 0.8
Undeveloped flows off-site to west 6 C1 0.02 0.20 5.0 0.00 2.85 0.0
TOTAL RUNOFFSTREET/SWALE PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
39705.01
DIRECT RUNOFF
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Project Name: Home2Suites
Subdivision: Harmony Village Project No.:
Location: Fort Collins Calculated By: DRC
Design Storm: Checked By: 0
Date: 1/18/16
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
Flow passing over pavers
through chase drain into LID 1 A1 0.41 1.00 5.0 0.41 9.95 4.1 0.5
Total flows entering LID #1 2 A2 0.31 0.86 5.0 0.27 9.95 2.7 5.0 0.68 9.95 6.8 0.6
Total flows entering LID #2 3 A3 0.37 1.00 5.0 0.37 9.95 3.7 5.0 1.05 9.95 10.4
Flow passing over Paver Section #1 4 B1 0.12 1.00 5.0 0.12 9.95 1.2 0.5
Flow exiting off-site to Delany Drive 5 B2 0.88 1.00 6.2 0.88 9.31 8.2 6.2 1.00 9.31 9.3 0.8
Undeveloped flows off-site to west 6 C1 0.02 0.25 5.0 0.01 9.95 0.1
TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
39705.01
100-Year
DIRECT RUNOFF
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Channel Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc. Monday, Jan 18 2016
Design Point 1 - Chase Drain 1 (4.1 cfs-100yr)
Rectangular
Bottom Width (ft) = 3.00
Total Depth (ft) = 0.50
Invert Elev (ft) = 1.00
Slope (%) = 0.50
N-Value = 0.013
Calculations
Compute by: Known Q
Known Q (cfs) = 4.10
Highlighted
Depth (ft) = 0.38
Q (cfs) = 4.100
Area (sqft) = 1.14
Velocity (ft/s) = 3.60
Wetted Perim (ft) = 3.76
Crit Depth, Yc (ft) = 0.39
Top Width (ft) = 3.00
EGL (ft) = 0.58
0 .5 1 1.5 2 2.5 3 3.5 4
Elev (ft) Depth (ft)
Section
0.75 -0.25
1.00 0.00
1.25 0.25
1.50 0.50
1.75 0.75
2.00 1.00
Reach (ft)
Weir Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc. Monday, Jan 18 2016
Design Point 2 - Overflow Weir (6.8 cfs - 100yr)
Trapezoidal Weir
Crest = Sharp
Bottom Length (ft) = 4.00
Total Depth (ft) = 0.75
Side Slope (z:1) = 4.00
Calculations
Weir Coeff. Cw = 3.33
Compute by: Known Q
Known Q (cfs) = 6.80
Highlighted
Depth (ft) = 0.51
Q (cfs) = 6.800
Area (sqft) = 3.08
Velocity (ft/s) = 2.21
Top Width (ft) = 8.08
0 1 2 3 4 5 6 7 8 9 10 11 12
Depth (ft) Design Point 2 - Overflow Weir (6.8 cfs - 100yr) Depth (ft)
-0.50 -0.50
0.00 0.00
0.50 0.50
1.00 1.00
Length (ft)
Weir W.S.
Channel Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc. Monday, Jan 18 2016
Bio-Swale Section - at Southern Property Line (10.4 cfs)
Rectangular
Bottom Width (ft) = 4.00
Total Depth (ft) = 1.50
Invert Elev (ft) = 4960.50
Slope (%) = 0.60
N-Value = 0.030
Calculations
Compute by: Known Q
Known Q (cfs) = 10.40
Highlighted
Depth (ft) = 0.93
Q (cfs) = 10.40
Area (sqft) = 3.72
Velocity (ft/s) = 2.80
Wetted Perim (ft) = 5.86
Crit Depth, Yc (ft) = 0.60
Top Width (ft) = 4.00
EGL (ft) = 1.05
0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5
Elev (ft) Depth (ft)
Section
4960.00 -0.50
4960.50 0.00
4961.00 0.50
4961.50 1.00
4962.00 1.50
4962.50 2.00
4963.00 2.50
Reach (ft)
Weir Report
Hydraflow Express Extension for AutoCAD® Civil 3D® 2012 by Autodesk, Inc. Monday, Jan 18 2016
Design Point 3 - Overflow Chase Drain (10.4cfs - 100yr) - 3 in. overtop Sidewalk
Compound Weir
Crest = Sharp
Bottom Length (ft) = 16.00
Total Depth (ft) = 0.75
Length, x (ft) = 3.00
Depth, a (ft) = 0.50
Calculations
Weir Coeff. Cw = 3.33
Compute by: Known Q
Known Q (cfs) = 10.40
Highlighted
Depth (ft) = 0.72
Q (cfs) = 10.40
Area (sqft) = 5.02
Velocity (ft/s) = 2.07
Top Width (ft) = 16.00
0 2 4 6 8 10 12 14 16 18 20
Depth (ft) Design Point 3 - Overflow Chase Drain (10.4cfs - 100yr) - 3 in. overtop Sidewalk Depth (ft)
-0.50 -0.50
0.00 0.00
0.50 0.50
1.00 1.00
Length (ft)
Weir W.S.
Subdivision: Harmony Village Project Name: Home2Suites
Location: Fort Collins Project No.: 39705.01
Calculated By: DRC
Checked By: 0
Date: 1/18/16
Improved Basins
Basin Area % Impervious
A1 0.41 88.4
A2 0.31 60.9
A3 0.37 88.4
B1 0.12 76.3
C 0.02 5.0
TOTAL 1.23 78.9
Water Quality Sizing
WQCV = (0.91I
3
- 1.19I
2
+ 0.78I) * A/12
Forebay release rate = 2% of 100-year in flow
X:\3970000.all\3970501\Excel\Drainage\3970501Drainage_Calcs.xls Page 1 of 1 1/19/2016
Stormwater Facility Name:
Facility Location & Jurisdiction:
User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined
Watershed Slope = 0.005 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs]
Watershed Length-to-Width Ratio = 2.00 L:W 0.00 0.00
Watershed Area = 1.23 acres
Watershed Imperviousness = 78.9% percent
Percentage Hydrologic Soil Group A = 0.0% percent
Percentage Hydrologic Soil Group B = 0.0% percent
Percentage Hydrologic Soil Groups C/D = 100.0% percent
User Input: Detention Basin Characteristics
WQCV Design Drain Time = 40.00 hours
After completing and printing this worksheet to a pdf, go to:
https://maperture.digitaldataservices.com/gvh/?viewer=cswdif,
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Routed Hydrograph Results
Design Storm Return Period = WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year
Two-Hour Rainfall Depth = 0.53 0.98 136% 1.71 2.31 2.91 3.67 in
Calculated Runoff Volume = 0.033 0.078 0.116 0.152 0.216 0.278 0.361 acre-ft
OPTIONAL Override Runoff Volume = acre-ft
Inflow Hydrograph Volume = 0.032 0.077 0.116 0.151 0.215 0.277 0.360 acre-ft
Time to Drain 97% of Inflow Volume = #N/A #N/A #N/A #N/A #N/A #N/A #N/A hours
Time to Drain 99% of Inflow Volume = #N/A #N/A #N/A #N/A #N/A #N/A #N/A hours
Maximum Ponding Depth = #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A
Maximum Ponded Area = #N/A #N/A #N/A #N/A #N/A #N/A #N/A acres
Maximum Volume Stored = #N/A #N/A #N/A #N/A #N/A #N/A #N/A acre-ft
Stormwater Detention and Infiltration Design Data Sheet
Water Quality Basins #1 & #2
Home2 Suites at Harmony Village, City of Fort Collins
Workbook Protected Worksheet Protected
SDI_Design_Data_FC_Rainfall (2).xlsm, Design Data 1/19/2016, 3:03 PM
Doing_Clear_Formatting Yes =
CountA= 1
0 1 2 3
#N/A
#N/A
0 1 2 3
#N/A
#N/A
Check Data Set 0 Check Data Set 0
Stormwater Detention and Infiltration Design Data Sheet
Area
Discharge
0
1
2
3
4
5
6
7
8
0.1 1 10
FLOW [cfs]
TIME [hr]
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
WQCV IN
WQCV OUT
0
0.2
0.4
0.6
0.8
1
1.2
0.1 1 10 100
PONDING DEPTH [ft]
DRAIN TIME [hr]
100YR
50YR
25YR
10YR
5YR
2YR
WQCV
SDI_Design_Data_FC_Rainfall (2).xlsm, Design Data 1/19/2016, 3:03 PM
Subdivision Harmony Village Project Name: Home2Suites
Location Fort Collins Project No. 39705.01
By: DRC
Volume=1/3 x Depth x (A+B+(A*B)^0.5) Checked By: 0
A - Upper Surface Date: 1/18/16
B - Lower Surface
LID Basin (West)
Stage Stage Elevation Stage Surface Area Stage Volume Cumulative Volume Cumulative Volume
(square feet) (cubic feet) (cubic feet) (acre feet)
0.00 4960.00 100 0 0 0.00
0.50 4960.50 396 116 116 0.00
1.00 4961.00 958 328 444 0.01
1.50 4961.50 1,480 605 1,049 0.02
2.00 4962.00 2,013 870 1,919 0.04
Volume (acre feet) Volume Water Surface Elevation
POND VOLUME CALCULATIONS
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Subdivision Harmony Village Project Name: Home2Suites
Location Fort Collins Project No. 39705.01
By: DRC
Volume=1/3 x Depth x (A+B+(A*B)^0.5) Checked By: 0
A - Upper Surface Date: 1/18/16
B - Lower Surface
LID Basin (East)
Stage Stage Elevation Stage Surface Area Stage Volume Cumulative Volume Cumulative Volume
(square feet) (cubic feet) (cubic feet) (acre feet)
0.00 4959.50 270 0 0 0.00
0.25 4959.75 360 78 78 0.00
0.50 4960.00 427 98 176 0.00
0.75 4960.25 497 115 291 0.01
1.00 4960.50 610 138 429 0.01
1.25 4960.75 816 178 607 0.01
1.50 4961.00 1,190 249 856 0.02
Volume (acre feet) Volume Water Surface Elevation
POND VOLUME CALCULATIONS
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APPENDIX D
EXISTING & PROPOSED DRAINAGE PLANS
FINAL DRAINAGE AND
EROSION CONTROL REPORT
HARMONY VILLAGE P.U.D.
Prepared for:
Dial Companies
11506 Nicholas St., #200
Omaha, Nebraska 68154
(402) 493-2800
Prepared by:
JR Engineering, Ltd.
2620 E. Prospect Road, Suite 190
Fort Collins, Colorado 80525
(970) 491-9888
November 6, 1998
Revised January 6, 1999
Revised February 6, 1999
Revised September 15, 2014
Job Number 9168.00
2
Local drainage facilities were designed to convey peak flows from the 100-year storm event
calculated using the Rational Method. Regional hydrology was evaluated using UDSWM2-
PC Rainfall/Runoff Prediction and Watershed Simulations Program (SWMM) endorsed by the
Urban Drainage and Flood Control District.
1.5 Master Drainage Basin
Harmony Village P.U.D. is included in the McClellands Drainage Basin. The master study for
this area is the “McClellands Basin Master Drainage Plan” by Greenhorn and O’Mara, Inc.,
1986. Harmony Village is sub-basin 301 and the detention pond associated with Harmony
Village P.U.D. is conveyance element 301 of the most recent SWM model for the
McClellands Basin, dated July 1997.
2. HISTORIC (EXISTING) DRAINAGE
The historic (existing) flows for this site consist of the flows from the site. There are no off-
site flows entering the property. The drainage pattern for the property is via overland flow in
a southeasterly direction at approximately 1- percent slope.
The existing drainage from the existing warehouse site to the west of Harmony Village
P.U.D. is routed southerly in an existing swale around the east edge of the warehouse site
onto the Harmony Village P.U.D. property, diverted westerly to the railroad right-of-way,
diverted southerly and conveyed along the railroad tracks to an existing downstream
detention pond. This drainage pattern is being maintained with the development of the
Harmony Village P.U.D. site.
Note: The release rate for the detention pond was limited to 0.5 cfs/acre for the 100-year
event and 0.2 cfs/acre for the 10-year event in accordance with the “McClellands
Basin Master Drainage Plan”. Therefore, historic (existing) runoff calculations are
not included as part of this report.
3
3. LOCAL DEVELOPED DRAINAGE DESIGN
3.1 Method
The Rational Method was used to determine both the 10-year and 100-year flows for the sub-
basins indicated in this drainage report. A detailed description of the hydrologic analysis is
provided in Section 3.4 of this report.
3.2 General Flow Routing
Flows within this site will take the form of overlot, swale, gutter, and pipe flow. The existing
drainage patterns have been maintained where possible. All grading has been designed to
carry flows away from structures to the proposed drainage facilities.
The proposed drainage facilities for this site consist of proposed sump inlets, curb cuts,
swales, drainage pipes and a box culvert. The majority of the site will drain to the proposed
detention pond located in the southeast corner of the property. The detention pond outlets to
the existing storm system for the Harmony Crossing Subdivision located to the south. Flows
from Harmony Village P.U.D. and Harmony Crossing enter the McClellands Drainageway
and eventually reach the Cache La Poudre River.
The southern portion of the site was included in the detention calculations and drainage report
for Harmony Crossing. This includes the assisted living area, Wilmington Drive, the tot lot,
and the western parking lot. This area will be free released to the south and detained in the
existing pond for Harmony Crossing as stated in the Final Drainage and Erosion Control
Study for Harmony Crossing, P.U.D. (RBD, 1994).
3.3 Proposed Drainage Plan
A qualitative summarization of the drainage patterns within each sub-basin and at each design
point is provided in the following paragraphs. Discussions of the detailed design of drainage
facilities identified in this section are included in the following sections.
Runoff from Subbasin 101 is conveyed via sheet flow, gutter flow and through cross-
pans to a proposed sump condition curb cut located at Design Point 1. The curb cut
outlets into a proposed grouted boulder channel in Subbasin 105, the upper portion
of the large detention pond (Pond B).
Runoff from Subbasin 101 is conveyed via sheet flow, gutter flow and through cross-
pans to a proposed sump condition curb cut located at Design Point 1. The curb cut
outlets into a proposed grouted boulder channel in Subbasin 105, the upper portion
of the large detention pond (Pond B).
outlets into a proposed grouted boulder channel in
pans to a proposed sump condition curb cut located at Design Point 1. The curb cut
outlets into a proposed grouted boulder channel in
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5
Runoff from Subbasin 110, the large detention pond (Pond A) is conveyed to the
outlet structure in the southeast corner of the said pond at Design Point 10. (See
below for discussion of Detention Pond.)
Subbasin 111 includes the west half of Timberline Road adjacent to the southerly
portion of Harmony Village P.U.D. Runoff is conveyed via gutter flow along the
west side of Timberline to an existing detention pond in the southeast corner of
Harmony Crossing as described in the approved drainage report for that development.
Calculations in Appendix C show that the additional flow to the 10’ curb inlet will not
exceed its capacity for the 100-year event.
Subbasin 112 is conveyed via sheet flow and gutter flow to a proposed curb cut
located at Design Point 12. The curb cut outlets into a proposed concrete channel in
Subbasin 105, the upper portion of the large detention pond (Pond B).
Runoff from Subbasin 113, is conveyed via sheet flow and gutter flow to a proposed
sump condition inlet on the east side of Delany Street south of Timberwood Drive at
Design Point 13. The inlet outfalls into a proposed underground storm sewer pipe
system that outlets into Subbasin 110, the large detention pond (Pond A). Any flow
that is unable to enter the inlet during the 100-year event will proceed easterly into the
proposed parking lot via sheet flow and gutter flow to the proposed inlet in Subbasin
109.
Runoff from Subbasin 114, is conveyed via sheet flow and gutter flow to a proposed
sump condition inlet on the east side of parking lot adjacent to Delany Street south of
Timberwood Drive at Design Point 14. The inlet outfalls into a proposed underground
storm sewer pipe system that joins the storm sewer pipe from Subbasin 113 and
outlets into Subbasin 110, the large detention pond (Pond A). If any clogging of the
inlet occurs, the runoff will begin to pond in the parking lot until it begins to flow out
the entrance to Delany. At this point, the runoff will flow easterly across Delany
Drive toward Design Point 13 in Subbasin 113. The excess flow proceeds east into
the proposed parking lot via sheet flow and gutter flow to the proposed inlet in
Subbasin 109.
Runoff from Subbasin 115 is conveyed via sheet flow and gutter flow south along
Delany Drive to Design Point 15. From here, runoff is conveyed to the existing
detention pond in the southeast corner of Harmony Crossing as described in the
approved drainage report for that development.
Runoff from Subbasin 116 is conveyed via sheet flow and gutter flow to Wilmington
Drive. Flows are conveyed easterly along Wilmington Drive to Delany Drive within
Harmony Crossing at Design Point 16. The flows are then conveyed to the existing
detention pond in the southeast corner of Harmony Crossing as described in the
approved drainage report for that development.
Subbasin 109.
the proposed parking lot via sheet flow and gutter flow to the proposed inlet in
Drive toward Design Point 13 in Subbasin 113. The excess flow proceeds east into
the entrance to Delany. At this point, the runoff will flow easterly across Delany
inlet occurs, the runoff will begin to pond in the parking lot until it begins to flow out
outlets into Subbasin 110, the large detention pond (Pond A). If any clogging of the
storm sewer pipe system that joins the storm sewer pipe from Subbasin 113 and
Timberwood Drive at Design Point 14. The inlet outfalls into a proposed underground
sump condition inlet on the east side of parking lot adjacent to Delany Street south of
Runoff Runoffproposed from Subbasin 114, is conveyed via sheet flow and gutter flow to a
9
Table 3.1 – Drainage Summary Table
Design Tributary Area
C (10) tc (10) Q(10)tot C (100) tc (100) Q(100)tot DRAINAGE
Sub-basin STRUCTURE
Point (ac) (min) (cfs) (min) (cfs) /REMARKS
1 101 11.72 0.72 14.4 32.06 0.89 11.6 70.4 10' Curb Cut
2 102 0.65 0.84 5.0 3.05 1.00 10.0 4.6 2' Curb Cut
3 103 0.53 0.95 5.0 2.80 1.00 10.0 3.8 5' Curb Cut & Sidewalk
Chase
4 104 3.84 0.68 7.5 15.00 0.86 10.0 27.2 10' Curb Cut
105 0.66 0.13 12.4 0.35 0.16 12.4 0.7
5 101-105 + 112 17.88 0.70 18.8 42.18 0.88 18.8 84.1 2'x8' box
6 106 0.39 0.88 5.0 14.07 1.00 10.0 50.6 8' Curb Cut
7 107 0.25 0.50 5.7 0.67 0.62 10.0 1.1 Double Combination inlet
8 108 0.39 0.82 5.0 1.78 1.00 10.0 2.8 Double Combination inlet
9 109 0.60 0.64 5.9 2.04 0.80 10.0 9.2 8’ Type R inlet
110 1.28 0.10 11.6 0.54 0.13 10.0 1.1
10 101-114 29.00 0.71 18.9 69.14 0.89 18.9 137.9
11 111 0.45 0.95 7.5 2.11 1.00 10.0 4.1 free release
12 112 0.48 0.91 5.0 2.45 1.00 10.0 3.4 2' Curb Cut
13 113 1.16 0.68 8.9 3.67 0.85 10.0 14.5 5' Type R inlet
14 114 6.46 0.84 16.4 19.50 1.00 14.0 39.9 15' Type R inlet
15 115 0.19 0.59 5.0 0.61 0.74 10.0 1.0 free release
16 116 2.83 0.74 8.7 9.88 0.93 10.0 18.7 free release
17 117 0.81 0.27 13.9 0.84 0.34 13.9 1.7 free release
18 118 0.88 0.95 5.0 4.66 1.00 10.0 6.3 2' Curb Cut & Sidewalk
Chase
19 119 1.60 0.44 12.1 2.90 0.55 11.1 6.0 free release
20 120 0.10 0.10 5.6 0.05 0.13 10.0 0.1
O-1 OS-1 4.54 0.71 16.8 11.44 0.89 16.8 22.8
O-2 OS-2 1.02 0.49 10.6 2.19 0.62 10.2 27.2
4. REGIONAL DRAINAGE EVALUATION
4.1 Detention Pond Design
Detention is required and will be provided for on the Harmony Village site. The proposed
detention pond area is located in the southeast corner of the site. The proposed outlet
structure connects to the existing pipe under Rockport Court and outlets into an existing
swale parallel to Timberline Road that drains to the existing detention pond for the Harmony
Crossing Subdivision. The proposed detention pond for Harmony Village consists of two
areas that are interconnected by a box culvert under Timberwood Drive. The box culvert
connecting the ponds was sized so that peak 100-year flow can pass freely without being
15
7. REFERENCES
1. City of Fort Collins, “Storm Drainage Design Criteria and Construction Standards”
(SDDCCS), May 1984.
2. “Preliminary Drainage and Erosion Control Report for Harmony Village P.U.D.”, JR
Engineering, Ltd., May 1, 1998, Revised July 15, 1998.
3. “Final Drainage and Erosion Control Study for Harmony Crossing P.U.D., Fort
Collins, Colorado”, RBD, Inc. Engineering Consultants, January 28, 1994.
4. “McClellands Basin Master Drainage Plan”, Greenhorn and O’Mara, 1986.
5. Soil Survey of Larimer County Area, Colorado. United States Department of
Agriculture Soil Conservation Service and Forest Service, 1980.
6. Urban Drainage and Flood Control District, “Urban Storm Drainage Criteria
Manual”, Volumes 1 and 2, dated March 1969, and Volume 3, dated September
1992.
A Westrian Company
HOME2 SUITES HARMONY VILLAGE
EXISTING DRAINAGE CONDITIONS
Know what's
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
Larimer County, Colorado
UTILITY PLAN APPROVAL
LarimerDate County Engineer
tc Q2 Q100
C100 C5 (min) (cfs) (cfs)
EX1 1.67 0.74 0.59 12.44 2.0 8.8
EX2 0.28 0.25 0.20 10.56 0.1 0.5
Existing Runoff Summary Table
Basin ID Area (acres)
HOME2 SUITES
X:\3970000.all\3970501\Drawings\Sheet Dwgs\Drainage Report\3970501DRH.dwg, EXISTING DRAINAGE (24X36), 1/19/2016 3:50:28 PM
A Westrian Company
HOME2 SUITES HARMONY VILLAGE
PROPOSED DRAINAGE CONDITIONS
Know what's
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
Larimer County, Colorado
UTILITY PLAN APPROVAL
LarimerDate County Engineer
tc Q2 Q100
C100 C5 (min) (cfs) (cfs)
A1 0.41 1.00 0.83 5.00 1.0 4.1
A2 0.31 0.86 0.69 5.00 0.6 2.7
A3 0.37 1.00 0.88 5.00 0.9 3.7
B1 0.12 1.00 0.81 5.00 0.3 1.2
B2 0.88 1.00 0.90 6.17 2.1 8.2
C1 0.02 0.25 0.20 5.00 0.0 0.1
Runoff Summary Table
Basin ID Area (acres)
HOME2 SUITES
X:\3970000.all\3970501\Drawings\Sheet Dwgs\Drainage Report\3970501DRF.dwg, Proposed Drainage (24X36), 1/19/2016 3:49:58 PM
APPENDIX E
LID EXHIBITS
Know what's
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
Larimer County, Colorado
UTILITY PLAN APPROVAL
LarimerDate County Engineer
New Impervious Area 30,589 sq. ft.
Required Minimum Impervious Area to be Treated 15,295 sq. ft.
(=50% of new impervious area)
Area of Paver Section #1 2,247 sq. ft.
Run-on area for Paver Section #1 (1.0:1) 2,254 sq. ft.
Area of Paver Section #2 790 sq. ft.
Run-on area for Paver Section #2 (1.1:1) 862 sq. ft.
Impervious Area Treated by LID Treatment Method #1 - LID Basin #1 20,651 sq. ft.
Impervious Area Treated by LID Treatment Method #2 - LID Basin #2 32,323 sq. ft.
Total Impervious Area Treated (100%) 35,439 sq. ft.
New Pavement Area 11,583 sq. ft.
Required Minimum Area of Porous Pavement (=25% of new pavement area) 2,896 sq. ft.
Area of Paver Section #1 2,247 sq. ft.
Area of Paver Section #2 790 sq. ft.
Total Porous Pavement Area 3,037 sq. ft.
Actual % of Porous Pavement Provided 26.2%
50% On-Site Treatment by LID Requirement
25% Porous Pavement Requirement
X:\3970000.all\3970501\Drawings\Sheet Dwgs\PDP\3970501LID-ImperviousArea.dwg, LID-Impervious Area, 1/19/2016 3:52:43 PM
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