HomeMy WebLinkAbout2601 CANTON CT. - PDP/FDP - FDP160033 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE AND EROSION
CONTROL STUDY
2601 CANTON COURT
Prepared for:
Dan Bernth
Doberstein Lemburg Commerical, Inc
1401 Riverside Avenue
Fort Collins, CO 80524
Prepared by:
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, Colorado 80550
(970) 686-6939
June 10, 2016
Job Number 347-09
ii
June 10, 2016
Heather McDowell
City of Fort Collins Stormwater
700 Wood Street
Fort Collins, CO 80522-0580
RE: Final Drainage and Erosion Control Study for
2601 Canton Court
Dear Heather,
I am pleased to submit for your review and approval, this Final Drainage and Erosion Control
Study for 2601 Canton Court. I certify that this report for the drainage design was prepared in
accordance with the Master Plan and the criteria in the City of Fort Collins Storm Drainage
Manual.
I appreciate your time and consideration in reviewing this submittal. Please call if you have any
questions.
Sincerely,
Patricia Kroetch, P.E.
700 Automation Drive, Unit I
Windsor, CO 80550
Phone: 970-686-6939
Fax: 970-686-1188
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TABLE OF CONTENTS
TABLE OF CONTENTS ............................................................................................................... iii
1. GENERAL LOCATION AND DESCRIPTION
1.1 Location ...................................................................................................................1
1.2 Description of Property ............................................................................................1
2. DRAINAGE BASINS AND SUB-BASINS
2.1 Major Basin Description ..........................................................................................1
2.2 Sub-Basin Description .............................................................................................2
3. DRAINAGE DESIGN CRITERIA
3.1 Regulations ..............................................................................................................2
3.2 Development Criteria Reference and Constraints ...................................................2
3.3 Hydrologic Criteria ..................................................................................................2
3.4 Hydraulic Criteria ....................................................................................................2
4. DRAINAGE FACILITY DESIGN
4.1 General Concept ......................................................................................................3
4.2 Specific Flow Routing .............................................................................................3
4.3 Drainage Summary ..................................................................................................4
5. STORMWATER MANAGEMENT CONTROLS
5.1 Written Analysis .....................................................................................................5
5.2 SWMP Contact Information ...................................................................................6
5.3 Identification and location of all potential pollution sources ..................................7
5.4 Best Management Practices (BMP’s) for Stormwater Pollution Prevention ...........7
5.5 BMP Implementation ...............................................................................................9
6. CONCLUSIONS
6.1 Compliance with Standards ..................................................................................12
6.2 Drainage Concept ..................................................................................................12
7. REFERENCES ..................................................................................................................13
APPENDICES
A Vicinity Map
B Hydrologic Computations
C Hydraulic Computations
D Detention Pond Calculations
E BMP Schedule & Cost Estimate
1
1. GENERAL LOCATION AND DESCRIPTION
1.1 Location
The site is located on Lot 11, Prospect Industrial Park located in the Northeast Quarter of
Section 20, Township 7 North, Range 68 West of the 9Sixth Principal Meridian, in the
City of Fort Collins, Larimer County, Colorado. See the location map in Appendix A.
The project is located at the southwest end of Canton Court and is currently an
undeveloped parcel. The site bounded on all sides by existing commercial or office
developments.
1.2 Description of Property
The entire site consists of approximately 1.02 acres of land. The land is currently
undeveloped and is lower than the surrounding development. The site is currently drains
to the southwest, onto the site at 2025 Sharp Point Drive and eventually into Midpoint
Drive. Slopes on site range from approximately 0.5% to 12%.
This project will include the development of one multi tenant building with man doors on
the northwest and overhead doors on the southeast. There will be a private drive, a paved
parking lot on the northwest side of the building, a recycled asphalt storage area on the
southeast side of the building and landscaping on the remainder of the site. The majority
of the site will drain to the south and east into a grassed swale with underdrain and then
into detention storage on the adjacent lot. This detention pond will be contained in a
drainage easement that will be dedicated with this development proposal.
2. DRAINAGE BASINS AND SUB-BASINS
2.1 Major Basin Description
The proposed development lies within the Cache la Poudre Master Drainageway which
requires that detention be provided to attenuate runoff to the 2 year historic runoff rate. It
is also required that a minimum of fifty percent of the site runoff be treated using the
standard water quality treatment as described in the Fort Collins Stormwater Manual and
Low Impact Development (LID) treatment methods are required for seventy-five percent
of the site runoff.
2
2.2 Sub-basin Description
This site was most likely included in the original drainage report for Prospect Industrial
Park but this report cannot be located.
3. DRAINAGE DESIGN CRITERIA
3.1 Regulations
This report was prepared to meet or exceed the “City of Fort Collins Storm Drainage
Design Criteria Manual” specifications. Where applicable, the criteria established in the
“Urban Storm Drainage Criteria Manual” (UDFCD), developed by the Denver Regional
Council of Governments, has been used.
3.2 Development Criteria Reference and Constraints
The majority of the runoff from this site has been routed to flow to the proposed grassed
swale on the southeast side of the site and then routed to a proposed detention pond on
the adjacent property. A small portion of the site will flow to the northeast and into
Canton Court without entering the detention pond. The detention pond is restricted to a 2
year historic release rate with this design. The release rate for the detention pond has
been calculated to be 0.04 cfs which is equivalent to the 2 year historic runoff rate for this
site in an undeveloped condition.
3.3 Hydrologic Criteria
Runoff coefficients calculations were prepared for the 2 and 10-year minor and 100-year
major storm frequency utilizing the rational method. Detention is proposed on site with a
release rate equal to the 2 year historic runoff rate.
3.4 Hydraulic Criteria
The majority of the runoff from the site will flow to the southeast side of the lot and will
enter the grassed swale. A perforated pipe will collect the runoff and convey it to the
detention area and an overflow conveyance is also provided if the system fails or
becomes overloaded. A small portion of the runoff from the site will flow to the
northeast corner of the site and will be routed via concrete pan and metal sidewalk
3
culvert to Canton Court.
Detention and water quality extended detention are required for this site and will be
provided in the adjacent lot. The release from the detention pond will be restricted to the
2 year historic runoff which was calculated to be 0.40 cfs. The detention volume
required for this site was calculated to be 0.13 acre feet and the extended detention
volume was calculated to be 0.03 acre feet. The required volume will be accommodated
in the proposed pond and will have a maximum water surface of 4896.00. The pond will
discharge through a new drainage pipe to the curb in Midpoint Drive. This runoff will
then be routed to the existing pond on the east side of Sharp Point Drive.
4. DRAINAGE FACILITY DESIGN
4.1 General Concept
The runoff from this site will flow into the parking lot which will be constructed using
conventional materials (asphalt or concrete) or into the storage area which will be
recycled asphalt. The runoff from the site will then flow to the southeast and enter the
grassed swale. The flow will percolated into the subsurface material and enter the
perforated pipe. This pipe will convey runoff directly to the detention pond and, in an
overflow situation, a second pipe is provided to convey the runoff to the detention pond.
4.2 Specific Flow Routing
A summary of the drainage patterns within each basin is provided in the following
paragraphs.
Basin 1 includes a small portion of the paved parking lot and sidewalk. Runoff from this
basin will enter an opening in the curb and will flow to Canton Court via a concrete pan
and metal sidewalk culvert. No water quality extended detention or attenuation will be
provided for the runoff from this basin.
Basin 2 includes the remainder of the lot including the proposed building, a majority of
the paved parking lot and sidewalk, the recycled asphalt storage area and the grassed
swale. The runoff from this basin will flow to the south and east and into the grassed
swale. A perforated pipe will collect the flow and convey it to the offsite detention pond.
4
If the perforated pipe becomes clogged or is over capacity, the water will flow in the
grassed swale to the secondary pipe and be conveyed to the detention pond.
The offsite pond has been sized to accommodate runoff from Lot 11 but may be
expanded in the future to also accommodate expansion at 2025 Sharp Point Drive. This
pond also provides water quality extended detention and will release into a curb opening
in Midpoint Drive to the southwest of this site.
4.3 Drainage Summary
All runoff from this site will be safely conveyed via surface flow and piping to the
detention pond. The site will generally conform to the Cache la Poudre Master Drainage
plan which encompasses this site.
The City of Fort Collins will be responsible for maintenance of the existing storm
drainage facilities located within the right-of-way. The drainage facilities located outside
of the right of way (including the detention pond) will be maintained by the owner of Lot
11 and any other properties that will contribute runoff to the pond.
5
5. STORMWATER MANAGEMENT CONTROLS
5.1 Written Analysis
The soils on this site are classified by the USGS Soil Survey as Caruso Clay Loam and
are classified in the hydrologic group D. The soils are described as having a very slow
infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of
clays that have a high shrink-swell potential, soils that have a high water table, soils that
have a claypan or clay layer at or near the surface, and soils that are shallow over nearly
impervious material. These soils have a very slow rate of water transmission. The rainfall
erodibility is deemed to be moderate and the wind erodibility is deemed to be moderate to
high.
The site is surrounded by developed sites including streets, buildings and paved areas.
The construction shall utilize silt fence around the perimeter to control sediment transport
from rainfall and from wind. The silt fence that is located in the proposed pavement areas
will be removed prior to placing new pavement. Rock socks will be utilized in the
existing curb and proposed grassed swales to capture sediments that are not fully
contained by the silt fence placement. The locations of the rock socks will be in the areas
of concentrated flow such as in the existing curb, at the concrete sidewalk chase and on
the concrete pans.
The site will also utilize a vehicle tracking control pad to minimize sediment from being
tracked onto adjacent pavements. Sediment that is tracked will be removed and placed
within the site or permanently disposed of offsite. A concrete washout will be used on
site during the concrete placement. All hardened concrete will be disposed of offsite.
These BMP’s have not been located on the site map due to the fact that the site is very
small and these BMP’s will need to be placed by the contractor in locations that are most
beneficial and will minimize disruption of adjacent traffic.
Permanent erosion control consists of covering the soils with a building, concrete walks,
concrete pavement, recycled asphalt pavement and sod. No soil will be left exposed to
erosion after the construction is complete. Refer to the landscape plan for areas of and
instructions for placement of sod and soil amendments required prior to placement of
sod.
6
Refer to Appendix E for the timing of the construction phases and the sequential
installation of all BMP phasing for this site.
Refer to the Appendix E for the Erosion Control Surety calculations.
5.2 SWMP contact information
Permit holder:
Name:
Address:
Phone Number:
Email Address:
Appointed agent:
Name:
Address:
Phone Number:
Email Address:
7
5.3 Identification and location of all potential pollution sources
Potential Pollutant Source Activity Potential Pollutant Generated Applicable to
this project
Disturbed Areas Sediment X
Soil stockpiles Sediment X
Travel to adjacent public streets Tracked sediment X
Contaminated soils Sediment, chemicals Possible
Loading and unloading chemicals Chemicals
Unloading of building materials Trash, debris X
Outdoor storage of chemicals Chemicals
On site equipment maintenance Oil, grease
On site equipment fueling Diesel, gasoline X
Dust generating activities Particulates, sediment X
Use of fertilizer, pesticides, herbicides Fertilizer, pesticides
Use of detergents, solvents, oils Detergents, solvents, oil X
Waste dumpsters, waste piles Chemicals, trash, debris X
Concrete washout Concrete, sediment, wash water X
On site equipment washing Detergents, oil
On site asphalt batch plant Asphaltic cement, sediment
On site concrete batch plant Cement, sediment
Portable toilets Domestic sewage X
5.4 Best Management Practices (BMP’s) for Stormwater Pollution Prevention
Structural Practices for Erosion and Sediment Control
Structural practices for the site will consist mainly of silt fence and rock sock filters and are
described in detail in the following paragraphs. These BMP's are expected to change as the
construction progresses and it is the responsibility of the contractor to ensure appropriate BMP's
are in place and/or removed at the appropriate time in the construction sequence. All temporary
and permanent erosion and sediment control practices must be maintained and repaired as
needed to assure continued performance of their intended function.
Silt fence and rock sock filters shall be in place prior to commencement of construction
activities. During clearing and grubbing necessary for silt fence installation, all cleared material
shall be placed on the uphill side so that if erosion occurs from the cleared material, the sediment
will be trapped and not transported downstream. Rock socks shall be implemented in the existing
curb line as shown on the Drainage & Erosion Control Plan.
8
All BMP's shall be installed per the details shown on the construction plan set.
Temporary & Permanent Structural BMP’s:
Structural BMP Approximate location on site Applicable to this
Project
Silt Fence Site perimeter, refer to site map X
Straw bale dams
Rock Socks At existing sidewalk culverts, in existing
gutters, refer to site map X
Earthen diversion dams
Vegetated swales
Sediment trap/pond
Pipe slope drains
Geogrid
Inlet/outlet protection In the detention Pond X
Culverts Refer to site map X
Riprap
Erosion control mats
Inlet protection
Vehicle Tracking Control Pad At site entrance, refer to site map X
Concrete Washout To be located by Contractor X
Non-Structural Practices for Erosion and Sediment Control:
Soils exposed during the earthwork phase and landscape prep phase shall be kept in a roughened
condition by ripping or disking along land contours until mulch, vegetation, or other permanent
erosion control is installed. No large amount of soils (in excess of 15 yards) will be allowed to be
stock piled on site. Overburden from the utility pipe trenching will be piled adjacent to trenches
upstream of sediment controls and will be replaced in the trenches within 72 hours.
Excess excavated materials from the demolition and grading phases of the project that cannot be
reused on site will be exported as it is excavated. This includes any asphalt pavement from the
existing site that is to be removed.
A vehicle tracking pad will be installed at a location most beneficial to the site construction as
determined by the contractor. Vehicles will not be permitted in the excavated area if soil is
muddy. Gravel sub base will be placed and compacted in the areas indicated for pavement
following excavation. In the current pre construction state the site enables tracking of silt onto
the adjacent streets during wet conditions. During construction activities the street will be
monitored for foreign debris tracked out of the site and mechanical sweeping and clean up will
be performed as needed.
9
No area shall remain exposed by land disturbing activity for more than thirty (30) days before
required temporary or permanent erosion control (e.g. seed/mulch, landscaping, etc.) is installed.
Temporary & Permanent non-structural BMP’s:
Non-Structural BMP Approximate location on site Applicable to this
Project
Surface roughening Entire site X
Soil stockpile height limit (less than
10’)
Perimeter vegetative buffer northwest and southwest boundaries of
site X
Minimization of site disturbance
Mulch
Seed & mulch stockpiles after 30 days
Stockpile toe protection (silt fence,
wattles or ditch)
Preservation & protection of existing
vegetation & trees
northwest and southwest boundaries of
site X
Good site housekeeping (routine
cleanup of trash & constr debris) Entire Site X
Sweeping & scraping of hardscape
areas On and off site pavements X
Heavy equip staged on site, properly
maintained & inspected daily (no
onsite maintenance)
Staging area X
5.5 BMP Implementation
1) Phased BMP Implementation
BMP’s are expected to change as the construction progresses and it is the responsibility of
the contractor to ensure appropriate BMP’s are in place and/or removed at the appropriate
time in the construction sequence. A construction sequence schedule has been included on
the Drainage & Erosion Control Plan and included in the construction plans for this site.
All BMP’s shall be inspected and repaired or replaced as required to satisfy the conditions of
the Stormwater Discharge Permit. All BMP’s must be maintained and repaired as needed to
assure continued performance of their intended function. Refer to Appendix E for the BMP
schedule and estimated costs.
10
2) Materials Handling and Spill Prevention:
Materials Handling & Spill
Prevention BMP Approximate location on site
Applicable to this
Project
Portable toilets, anchored &
located away from drainages Contractor to determine X
Fuel storage located in bulk tanks
with secondary containment &
spill kit
Mobile fueling performed at least
200 feet away from drainages &
fully attended
Contractor to determine X
Fertilizers, form oil, solvents,
cleaners, detergent stored in 55 gal
or smaller containers, kept in
storage units
Contractor to determine X
Dumpsters containing used
chemicals containers & liquid
wastes kept covered
Contractor to determine X
Equipment cleaning (on site) uses
no detergents & flows to onsite
retention basin
In case of a release of fuel or other
chemicals, absorbent booms or
earthen berms will be immediately
constructed to contain the spill &
prevent runoff to adjacent surface
waters
Location of spill X
MSDS sheets for onsite chemicals
will be kept at the construction
trailer to facilitate spill response &
cleanup
Contractor to determine X
3) Dedicated Asphalt or Concrete Batch Plant:
Not proposed with this development
4) Vehicle Tracking Pad:
Vehicle tracking control pad shall be installed wherever construction vehicle access routes
intersect paved public roads. Vehicle tracking control pads shall be installed to minimize the
transport of sediment (mud) by runoff or vehicles tracking onto the paved surface. Any mud
tracked to public roads shall be removed on a daily basis and after any significant storm that
causes sediment to be transported. It is unlawful to track sediment/mud onto public streets
and may be enforced by the City of Fort Collins, by the State of Colorado or by the EPA.
11
5) Waste Management and Disposal:
Portable toilets will be anchored & periodically maintained by waste management company.
Dumpsters on site will be covered & periodically emptied by waste management company.
Concrete waste will be allowed to harden and then will be removed from site.
No washing activities will occur on site.
Location of the concrete washout is shown on the site map. The washout will be sufficiently
deep to accommodate all anticipated concrete truck wash water. Waste concrete will be
allowed to harden and be removed from site periodically as the washout reaches 50% of its
capacity. Truck wash water will not be allowed to reach the curb & gutter or any other water
course.
6) Groundwater and Stormwater Dewatering:
No groundwater was encountered during soils exploration therefore ground water is not
anticipated to be an issue. If groundwater is encountered a groundwater discharge permit
shall be obtained and a detailed report shall be completed describing the location and the
route of where pumped groundwater will be conveyed and the measures taken to prevent the
transport of any pollutants to downstream waters.
7) Inspection & Maintenance:
It is required that routine site inspections are performed to effectively address maintenance
and repair of Best Management Practices (BMP's). The site inspections are to performed by
the contractor or an inspector designated by the administrator at a minimum of once every
fourteen (14) calendar days on active construction sites and after any significant storm event
(an event causing runoff). As part of the site inspections the inspector is required to keep
documentation of
all inspections and BMP maintenance, including an updated Site Map indicating new BMP's
or the removal of BMP's since the previous inspection.
Any maintenance, repair, or necessary installation of BMP's that are noted during the
inspection must be completed within seven (7) calendar days from the date of the inspection.
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6. CONCLUSIONS
6.1 Compliance with Standards
All computations that have been completed within this report are in compliance with the
City of Fort Collins Storm Drainage Design Criteria Manual and the Cache la Poudre
Master Drainage Plan.
6.2 Drainage Concept
The proposed drainage concepts presented in this report and on the construction plans
adequately provide for conveyance of runoff to the detention areas. Conveyance
elements have been designed to pass required flows and to minimize future maintenance.
If, at the time of construction, groundwater is encountered, a Colorado Department of
Health Construction Dewatering Permit would be required.
13
7. REFERENCES
1. City of Fort Collins, “Storm Drainage Criteria Manual”, (SDCM), dated March,
1986.
2. 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
APPENDIX A
VICINITY MAP
B
APPENDIX B
HYDROLOGIC COMPUTATIONS
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria
Recommended % Impervious from Urban Storm Drainage Criteria Manual
Runoff %
coefficient Impervious
C 2 year 10 year 100 year
Streets, parking lots (asphalt): 0.95 100 0 0.10 0.22
Sidewalks (concrete): 0.95 90
Roofs: 0.95 90 0 0.21 0.46
Recycled asphalt: 0.40 40
Lawns (flat <2%, heavy soil): 0.20 0
SUBBASIN TOTAL TOTAL ROOF PAVED SIDEWALK RECYCLED LANDSCAPE RUNOFF RUNOFF RUNOFF RUNOFF %
DESIGNATION AREA AREA AREA AREA AREA ASPHALT AREA COEFF. COEFF. COEFF. COEFF. Impervious REMARKS
(ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C) 2 10 100
1 0.05 1,975 0 1,210 345 0 420 0.79 0.56 0.66 0.78 77
2 0.97 42,275 9,000 12,346 1,041 11,718 8,170 0.65 0.42 0.52 0.64 62
Total 1.02 44,250 9,000 13,556 1,386 11,718 8,590 0.66 0.43 0.52 0.64 62
Historic Lot 11 1.02 44,250 0 0 0 0 44,250 0.20 0.04 0.25 0.50 0
Equations
- Calculated C coefficients & % Impervious are area weighted
C = (Ci Ai) / At
Ci = runoff coefficient for specific area, Ai
Ai = areas of surface with runoff coefficient of Ci
n = number of different surfaces to consider
At = total area over which C is applicable; the sum of all Ai's
RUNOFF COEFFICIENTS & % IMPERVIOUS
KCD
Final Flow.xls Cval
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
2-yr storm
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
POINT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
1 1 0.05 0.56 46 1.0 6.6 35 1.7 0.016 2.6 0.2 6.8 81 10.5 6.8
2 2 0.97 0.42 46 1.0 8.3 380 0.5 0.016 1.4 4.5 12.8 426 12.4 12.4
Total 1.02 0.43 46 1.0 8.2 380 0.5 0.016 1.4 4.5 12.7 426 12.4 12.4
Historic Lot 11 1.02 0.04 172 1.6 21.4 131 0.7 0.030 0.9 2.5 23.9 303 11.7 11.7
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L
0.5
] / S
1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
STANDARD FORM SF-2
TIME OF CONCENTRATION - 2 YEAR
Final Flow.xls TOC-2
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
10-yr storm
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
POINT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
1 1 0.05 0.66 46 1.0 5.4 35 1.7 0.016 2.6 0.2 5.6 81 10.5 5.6
2 2 0.97 0.52 46 1.0 7.1 380 0.5 0.016 1.4 4.5 11.6 426 12.4 11.6
Total 1.02 0.52 46 1.0 7.0 380 0.5 0.016 1.4 4.5 11.5 426 12.4 11.5
Historic Lot 11 1.02 0.25 172 1.6 17.2 131 0.7 0.030 0.9 2.5 19.7 303 11.7 11.7
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
STANDARD FORM SF-2
TIME OF CONCENTRATION - 10 YEAR
Final Flow.xls TOC-10
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
100-yr storm
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C C100 Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
POINT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
1 1 0.05 0.79 0.78 46 1.0 3.9 35 1.70 0.016 2.6 0.2 4.1 81 10.5 5.0
2 2 0.97 0.65 0.64 46 1.0 5.7 380 0.50 0.016 1.4 4.5 10.1 426 12.4 10.1
Total 1.02 0.66 0.64 46 1.0 5.6 380 0.50 0.016 1.4 4.5 10.1 426 12.4 10.1
0 Historic Lot 11 1.02 0.20 0.50 172 1.6 12.1 131 0.66 0.030 0.9 2.5 14.6 303 11.7 11.7
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
TIME OF CONCENTRATION - 100 YR
STANDARD FORM SF-2
Final Flow.xls TOC-100
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (NEW IDF CURVE)
(2-YEAR)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
2-yr storm
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C2 tc i Q (2) from Q (2) Q(2)tot
Sub-basin (new) Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
1 1 0.05 0.56 6.8 2.55 0.1 0.1
2 2 0.97 0.42 12.4 2.02 0.8 0.8
Total 1.02 0.43 12.4 2.02 0.9 0.9
Historic Lot 11 1.02 0.20 11.7 2.07 0.4 0.4 Detention release rate
Q = Cf C
iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
I = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
NOTE: Intensity based on Figure 3-1, 1999 (Regional Analysis)
Final Flow.xls Q2
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (NEW IDF CURVE)
(10-YEAR)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
10-yr storm
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C10 tc i Q (10) from Q (10) Q(10)tot
Sub-basin (new) Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
1 1 0.05 0.66 5.6 4.68 0.1 0.1
2 2 0.97 0.52 11.6 3.56 1.8 1.8
Total 1.02 0.52 11.5 3.56 1.9 1.9
Historic Lot 11 1.02 0.25 11.7 3.54 0.9 0.9
Q = Cf C
iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
I = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
NOTE: Intensity based on Figure 3-1, 1999 (Regional Analysis)
Final Flow.xls Q10
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (NEW IDF CURVE)
(100-YEAR)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
DATE: 6/21/2016
100-yr storm
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Des. Area A C100 tc i Q (100) from Q (100) Q(100)tot
(new) Design
Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
1 1 0.05 0.78 5.0 9.95 0.4 0.4
2 2 0.97 0.64 10.1 7.69 4.7 4.7
Total 1.02 0.64 10.1 7.69 5.0 5.0
Historic Lot 11 1.02 0.50 11.7 7.24 3.7 3.7
Q = C iA
Q = peak discharge (cfs)
C = runoff coefficient
I = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
NOTE: Intensity based on Figure 3-1, 1999 (Regional Analysis)
Final Flow.xls Q100
C
APPENDIX C
HYDRAULIC CALCULATIONS
Weir Check of Channel Sizing
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: ppk
SUBMITTED BY: North Star Design
DATE: 6/21/2016
Solve for h using Weir Equation
Q = CLH3/2
where C = weir coefficient
H = overflow height
L = length of the weir
Sidewalk Culvert in Basin 1
Q = 0.40 cfs
C = 2.62
L = 2.00 ft
Solve for H= 0.18 ft
Project:
Pipe ID:
Design Information (Input)
Pipe Invert Slope So = 0.0300 ft/ft
Pipe Manning's n-value n = 0.0120
Pipe Diameter D = 12.00 inches
Design discharge Q = 4.70 cfs
Full-flow Capacity (Calculated)
Full-flow area Af = 0.79 sq ft
Full-flow wetted perimeter Pf = 3.14 ft
Half Central Angle Theta = 3.14 radians
Full-flow capacity Qf = 6.70 cfs
Calculation of Normal Flow Condition
Half Central Angle (0<Theta<3.14) Theta = 1.81 radians
Flow area An = 0.51 sq ft
Top width Tn = 0.97 ft
Wetted perimeter Pn = 1.81 ft
Flow depth Yn = 0.62 ft
Flow velocity Vn = 9.24 fps
Discharge Qn = 4.70 cfs
Percent Full Flow Flow = 70.15% of full flow
Normal Depth Froude Number Frn = 2.25 supercritical
Calculation of Critical Flow Condition
Half Central Angle (0<Theta-c<3.14) Theta-c = 2.50 radians
Critical flow area Ac = 0.74 sq ft
Critical top width Tc = 0.60 ft
Critical flow depth Yc = 0.90 ft
Critical flow velocity Vc = 6.31 fps
Critical Depth Froude Number Frc = 1.00
CIRCULAR CONDUIT FLOW (Normal & Critical Depth Computation)
2601 Canton Court
Pipe between grassed swale & detention pond
Culvert.xls, Pipe 6/21/2016, 1:19 PM
Project:
Pipe ID:
Design Information (Input)
Pipe Invert Slope So = 0.0050 ft/ft
Pipe Manning's n-value n = 0.0120
Pipe Diameter D = 12.00 inches
Design discharge Q = 0.40 cfs
Full-flow Capacity (Calculated)
Full-flow area Af = 0.79 sq ft
Full-flow wetted perimeter Pf = 3.14 ft
Half Central Angle Theta = 3.14 radians
Full-flow capacity Qf = 2.74 cfs
Calculation of Normal Flow Condition
Half Central Angle (0<Theta<3.14) Theta = 1.07 radians
Flow area An = 0.16 sq ft
Top width Tn = 0.88 ft
Wetted perimeter Pn = 1.07 ft
Flow depth Yn = 0.26 ft
Flow velocity Vn = 2.49 fps
Discharge Qn = 0.40 cfs
Percent Full Flow Flow = 14.60% of full flow
Normal Depth Froude Number Frn = 1.02 supercritical
Calculation of Critical Flow Condition
Half Central Angle (0<Theta-c<3.14) Theta-c = 1.07 radians
Critical flow area Ac = 0.16 sq ft
Critical top width Tc = 0.88 ft
Critical flow depth Yc = 0.26 ft
Critical flow velocity Vc = 2.45 fps
Critical Depth Froude Number Frc = 1.00
CIRCULAR CONDUIT FLOW (Normal & Critical Depth Computation)
2601 Canton Court
Detention pond outlet pipe
Det Pond outlet.xls, Pipe 6/21/2016, 1:21 PM
D
APPENDIX D
DETENTION POND CALCULATIONS
6/10/2016
Calculation for Required LID Treatment
New Impervious Area 22556 sq. ft.
Required Minimum Impervious Area to be Treated (75%) 16917 sq. ft.
Impervious Area Treated by LID Treatment Method #1 (grassed
swale) 21346 sq. ft.
Impervious Area Treated by Porous pavement 0 sq. ft.
Total Impervious Area Treated 21346 sq. ft.
Calculation for Required Porous Pavement
New Pavement Area 13556 sq. ft.
Required Minimum Area of Porous Pavement (25%) 3389 sq. ft.
Area of Paver Section 0 sq. ft.
Run‐on area for Paver Section (up to 3:1 is permited) 0 sq. ft.
Total Porous Pavement Area 0 sq. ft.
2601 Canton Court
LID Summary Table
Project:
Basin ID:
Design Information (Input): Design Information (Input):
Catchment Drainage Imperviousness Ia = 63.00 percent Catchment Drainage Imperviousness I
a = 63.00 percent
Catchment Drainage Area A = 0.970 acres Catchment Drainage Area A = 0.970 acres
Predevelopment NRCS Soil Group Type = D A, B, C, or D Predevelopment NRCS Soil Group Type = D A, B, C, or D
Return Period for Detention Control T = 10 years (2, 5, 10, 25, 50, or 100) Return Period for Detention Control T = 100 years (2, 5, 10, 25, 50, or 100)
Time of Concentration of Watershed Tc = 12 minutes Time of Concentration of Watershed Tc = 12 minutes
Allowable Unit Release Rate q = 0.40 cfs/acre Allowable Unit Release Rate q = 0.40 cfs/acre
One-hour Precipitation P1 = 1.61 inches One-hour Precipitation P
1 = 2.61 inches
Design Rainfall IDF Formula i = C1* P1
/(C2+Tc
)^C3 Design Rainfall IDF Formula i = C1
* P1/(C2
+Tc)^C3
Coefficient One C1 = 28.50 Coefficient One C
1 = 28.50
Coefficient Two C2 = 10 Coefficient Two C
2 =10
Coefficient Three C3 = 0.789 Coefficient Three C
3 = 0.789
Determination of Average Outflow from the Basin (Calculated): Determination of Average Outflow from the Basin (Calculated):
Runoff Coefficient C = 0.53 Runoff Coefficient C = 0.64
Inflow Peak Runoff Qp-in = 2.03 cfs Inflow Peak Runoff Qp-in = 3.97 cfs
Allowable Peak Outflow Rate Qp-out = 0.39 cfs Allowable Peak Outflow Rate Qp-out = 0.39 cfs
Mod. FAA Minor Storage Volume = 2,177 cubic feet Mod. FAA Major Storage Volume = 5,704 cubic feet
Mod. FAA Minor Storage Volume = 0.050 acre-ft Mod. FAA Major Storage Volume = 0.131 acre-ft
5 <- Enter Rainfall Duration Incremental Increase Value Here (e.g. 5 for 5-Minutes)
Rainfall Rainfall Inflow Adjustment Average Outflow Storage Rainfall Rainfall Inflow Adjustment Average Outflow Storage
Duration Intensity Volume Factor Outflow Volume Volume Duration Intensity Volume Factor Outflow Volume Volume
minutes inches / hr acre-feet "m" cfs acre-feet acre-feet minutes inches / hr acre-feet "m" cfs acre-feet acre-feet
(input) (output) (output) (output) (output) (output) (output) (input) (output) (output) (output) (output) (output) (output)
5 5.42 0.019 1.00 0.39 0.003 0.017 5 8.78 0.038 1.00 0.39 0.003 0.035
10 4.32 0.031 1.00 0.39 0.005 0.025 10 7.00 0.060 1.00 0.39 0.005 0.054
15 3.62 0.038 0.91 0.35 0.007 0.031 15 5.87 0.075 0.91 0.35 0.007 0.068
20 3.13 0.044 0.81 0.31 0.009 0.036 20 5.08 0.087 0.81 0.31 0.009 0.078
25 2.78 0.049 0.75 0.29 0.010 0.039 25 4.50 0.096 0.75 0.29 0.010 0.086
30 2.50 0.053 0.71 0.27 0.011 0.042 30 4.05 0.104 0.71 0.27 0.011 0.093
35 2.28 0.056 0.68 0.26 0.013 0.044 35 3.69 0.110 0.68 0.26 0.013 0.098
40 2.09 0.059 0.66 0.25 0.014 0.045 40 3.40 0.116 0.66 0.25 0.014 0.102
45 1.94 0.062 0.64 0.25 0.015 0.047 45 3.15 0.121 0.64 0.25 0.015 0.106
50 1.81 0.064 0.62 0.24 0.017 0.048 50 2.94 0.126 0.62 0.24 0.017 0.109
55 1.70 0.066 0.61 0.24 0.018 0.048 55 2.76 0.130 0.61 0.24 0.018 0.112
60 1.61 0.068 0.60 0.23 0.019 0.049 60 2.60 0.134 0.60 0.23 0.019 0.114
65 1.52 0.070 0.60 0.23 0.021 0.049 65 2.47 0.137 0.60 0.23 0.021 0.116
70 1.45 0.072 0.59 0.23 0.022 0.050 70 2.34 0.140 0.59 0.23 0.022 0.118
75 1.38 0.073 0.58 0.23 0.023 0.050 75 2.23 0.143 0.58 0.23 0.023 0.120
80 1.32 0.075 0.58 0.22 0.025 0.050 80 2.14 0.146 0.58 0.22 0.025 0.121
85 1.26 0.076 0.57 0.22 0.026 0.050 85 2.05 0.149 0.57 0.22 0.026 0.123
90 1.21 0.077 0.57 0.22 0.027 0.050 90 1.97 0.151 0.57 0.22 0.027 0.124
95 1.17 0.078 0.57 0.22 0.029 0.050 95 1.89 0.154 0.57 0.22 0.029 0.125
100 1.12 0.080 0.56 0.22 0.030 0.050 100 1.82 0.156 0.56 0.22 0.030 0.126
105 1.09 0.081 0.56 0.22 0.031 0.049 105 1.76 0.158 0.56 0.22 0.031 0.127
110 1.05 0.082 0.56 0.22 0.033 0.049 110 1.70 0.160 0.56 0.22 0.033 0.127
115 1.02 0.083 0.55 0.21 0.034 0.049 115 1.65 0.162 0.55 0.21 0.034 0.128
120 0.99 0.084 0.55 0.21 0.035 0.048 120 1.60 0.164 0.55 0.21 0.035 0.129
125 0.96 0.085 0.55 0.21 0.037 0.048 125 1.55 0.166 0.55 0.21 0.037 0.129
130 0.93 0.086 0.55 0.21 0.038 0.048 130 1.51 0.168 0.55 0.21 0.038 0.129
Project:
Basin ID:
UDFCD DETENTION BASIN VOLUME ESTIMATING WORKBOOK Version 2.34, Released November 2013
DETENTION VOLUME BY THE MODIFIED FAA METHOD
2601 Canton Court
Basin 2
0
0.05
0.1
0.15
0.2
0.25
0 50 100 150 200 250 300 350
Volume (acre-feet)
Duration (Minutes)
Inflow and Outflow Volumes vs. Rainfall Duration
Minor Storm Inflow Volume Minor Storm Outflow Volume Minor Storm Storage Volume Major Storm Inflow Volume Major Storm Outflow Volume Major Storm Storage Volume
UD-Detention_v2.34.xls, Modified FAA 6/21/2016, 12:56 PM
STAGE - STORAGE TABLE
(100-YEAR)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design, Inc.
DATE: 6/10/2016
100 yr Detention Volume Required = 0.130
Water Quality Volume Required = 0.030
Total Volume Required= 0.160
Surface Incremental Total
Stage Area Storage Storage
(ft) (ft2) (ac-ft) (ac-ft)
4893.75 0
4894.0 1,103 0.002 0.002
WQCV 4894.61 2,963 0.027 0.030
4895.0 4,153 0.057 0.059
100 yr WSEL 4896.0 5,591 0.111 0.170 <==SPILLWAY ELEV
4897.0 6,601 0.140 0.310 <==TOP OF BERM ELEV
Detention Pond Outlet Sizing
(100 yr event)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design, Inc.
DATE: 6/21/2016
Submerged Orifice Outlet:
release rate is described by the orifice equation,
Qo = CoAo sqrt( 2g(h-Eo))
where Qo = orifice outflow (cfs)
Co = orifice discharge coefficient
g = gravitational acceleration = 32.2 ft/s
Ao = effective area of the orifice (ft2)
Eo = greater of geometric center elevation of the orifice or d/s HGL (ft)
h = water surface elevation (ft)
Qo = 0.40 cfs
outlet pipe dia = D = 12.0 in
Invert elev. = 4893.75 ft
Eo = 4893.88 ft
h = 4896.0 ft - 100 yr WSEL
Co = 0.62
solve for effective area of orifice using the orifice equation
Ao = 0.055 ft2
= 8.0 in2
orifice dia. = d = 3.18 in
Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering )
d / D = 0.27
kinematic viscosity, u = 1.22E-05 ft2/s
Reynolds no. = Red = 4Q/(pdu) = 1.57E+05
Co = (K in figure) = 0.62 check
Use d = 3.20 in
A o = 0.056 ft 2 = 8.04 in 2
Q max = 0.40 cfs
Emergency Overflow Spillway Sizing
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design, Inc.
DATE: 5/24/2005
Equation for flow over a broad crested weir
Q = CLH3/2
where C = weir coefficient = 2.8
H = overflow height
L = length of the weir
The pond has a spill elevation 0 ft above the maximum water surface elevation in the pond
Spillways will be designed with 0.25 ft flow depth, thus H = 0.5 ft
Size the spillway assuming that the pond outlet is completely clogged.
Q (100) = 4.7 cfs
Spill elev = 4896.00 ft 100 yr WSEL = 4896.0 ft
Top of berm elev.= 4897.00
Weir length required:
L = 5 ft
Use L = 10 ft
v = 0.67 ft/s
Stormwater Facility Name:
Facility Location & Jurisdiction:
User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined
Watershed Slope = 0.020 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs]
Watershed Length‐to‐Width Ratio = 1.00 L:W 0.00 0 0.00 0.00
Watershed Area =0.97acres 0.25 1,103 0.33 0.02
Watershed Imperviousness = 63.0% percent 0.86 2,963 0.66 0.06
Percentage Hydrologic Soil Group A =0.0%percent 1.25 4,153 1.00 0.26
Percentage Hydrologic Soil Group B = 0.0% percent 2.25 5,591 1.50 0.32
Percentage Hydrologic Soil Groups C/D = 100.0% percent 3.25 6,601 2.25 0.40
2.75 4.70
User Input 17 3.25 9.40
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
One‐Hour Rainfall Depth = 0.53 0.98 1.36 1.71 2.31 2.91 3.67 in
Calculated Runoff Volume = 0.020 0.048 0.077 0.104 0.153 0.200 0.263 acre‐ft
OPTIONAL Override Runoff Volume = acre‐ft
Inflow Hydrograph Volume = 0.019 0.048 0.076 0.103 0.152 0.200 0.263 acre‐ft
Time to Drain 97% of Inflow Volume = 91111 11 11 12 12 hours
Time to Drain 99% of Inflow Volume = 10 12 12 13 14 15 15 hours
Maximum Ponding Depth = 0.58 0.92 1.18 1.41 1.81 2.17 2.40 ft
Maximum Ponded Area = 0.048 0.072 0.090 0.101 0.114 0.125 0.132 acres
Maximum Volume Stored = 0.015 0.035 0.057 0.079 0.122 0.164 0.194 acre‐ft
Location for 1‐hr Rainfall Depths (use dropdown):
Workbook Protected Worksheet Protected
Stormwater Detention and Infiltration Design Data Sheet
2601 Canton Court
Fort Collins, CO
Drain time check_FC_Rainfall.xlsm, Design Data 6/21/2016, 1:45 PM
Doing_Clear_FoYes
CountA= 1
0123
#N/A
#N/A
0123
#N/A
#N/A
Check Data Set 1 Check Data Set 1
Area
Discharge
Stormwater Detention and Infiltration Design Data Sheet
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
0.5
1
1.5
2
2.5
3
0.1 1 10 100
PONDING DEPTH [ft]
DRAIN TIME [hr]
100YR
50YR
25YR
10YR
5YR
2YR
WQCV
Drain time check_FC_Rainfall.xlsm, Design Data 6/21/2016, 1:45 PM
E
APPENDIX E
BMP SCHEDULE & COST ESTIMATE
Project: Disturbed Acres: 1.30
EROSION CONTROL BMPs Units
Estimated
Quantity
Unit
Price
Total
Price
L.F. 1150 $3.00 $3,450.00
each 7 $85.00 $595.00
each 1 $1,500.00 $1,500.00
each 1 $1,200.00 $1,200.00
each 0 $210.00 $0.00
Sub-Total: $6,745.00
1.5 x Sub-Total: $10,117.50
Amount of security: $10,117.50
Total Acres x Price/acre: $1,560.00
$1,200.00 Sub-Total: $1,560.00
1.5 x Sub-Total: $2,340.00
Amount to Re-seed: $2,340.00
Minimum escrow amount: $3,000.00
Erosion Control Escrow: $10,117.50
Miniumum Escrow Amount
2601 Canton Court
Unit Price of Seeding per acre:
“The amount of the security must be based on one and one-half times the estimate of the cost to install the approved measures, or one and one-half times
the cost to re-vegetate the disturbed land to dry land grasses based upon unit cost determined by the City's Annual Revegetation and Stabilization Bid,
whichever is greater. In no instance, will the amount of security be less than one thousand five hundred dollars ($1,500) for residential development or three
thousand dollars ($3,000) for commercial development”
Rock Sock
Vehicle Tracking Control Pad
Final Escrow Amount
Erosion and Sediment Control Escrow/Security Calculation
for The City of Fort Collins
BMP Amount
Silt Fence
Concrete Washout
Inlet Protection
Reseeding Amount
6/21/2016 12:45 PM N:\347-09 Canton Court\drainage\ErosionEscrow.xls
135 0.90 0.086 0.55 0.21 0.039 0.047 135 1.47 0.169 0.55 0.21 0.039 0.130
140 0.88 0.087 0.54 0.21 0.041 0.047 140 1.43 0.171 0.54 0.21 0.041 0.130
145 0.86 0.088 0.54 0.21 0.042 0.046 145 1.39 0.172 0.54 0.21 0.042 0.130
150 0.84 0.089 0.54 0.21 0.043 0.045 150 1.36 0.174 0.54 0.21 0.043 0.131
155 0.82 0.090 0.54 0.21 0.045 0.045 155 1.32 0.175 0.54 0.21 0.045 0.131
160 0.80 0.090 0.54 0.21 0.046 0.044 160 1.29 0.177 0.54 0.21 0.046 0.131
165 0.78 0.091 0.54 0.21 0.047 0.044 165 1.26 0.178 0.54 0.21 0.047 0.131
170 0.76 0.092 0.54 0.21 0.049 0.043 170 1.24 0.180 0.54 0.21 0.049 0.131
175 0.75 0.092 0.54 0.21 0.050 0.042 175 1.21 0.181 0.54 0.21 0.050 0.131
180 0.73 0.093 0.53 0.21 0.051 0.042 180 1.18 0.182 0.53 0.21 0.051 0.131
185 0.72 0.094 0.53 0.21 0.053 0.041 185 1.16 0.184 0.53 0.21 0.053 0.131
190 0.70 0.094 0.53 0.21 0.054 0.040 190 1.14 0.185 0.53 0.21 0.054 0.131
195 0.69 0.095 0.53 0.21 0.055 0.040 195 1.12 0.186 0.53 0.21 0.055 0.131
200 0.68 0.096 0.53 0.21 0.057 0.039 200 1.09 0.187 0.53 0.21 0.057 0.130
205 0.66 0.096 0.53 0.21 0.058 0.038 205 1.07 0.188 0.53 0.21 0.058 0.130
210 0.65 0.097 0.53 0.21 0.059 0.037 210 1.06 0.189 0.53 0.21 0.059 0.130
215 0.64 0.097 0.53 0.21 0.061 0.037 215 1.04 0.191 0.53 0.21 0.061 0.130
220 0.63 0.098 0.53 0.20 0.062 0.036 220 1.02 0.192 0.53 0.20 0.062 0.130
225 0.62 0.098 0.53 0.20 0.063 0.035 225 1.00 0.193 0.53 0.20 0.063 0.129
230 0.61 0.099 0.53 0.20 0.065 0.034 230 0.99 0.194 0.53 0.20 0.065 0.129
235 0.60 0.099 0.53 0.20 0.066 0.033 235 0.97 0.195 0.53 0.20 0.066 0.129
240 0.59 0.100 0.53 0.20 0.067 0.033 240 0.95 0.196 0.53 0.20 0.067 0.128
245 0.58 0.101 0.53 0.20 0.069 0.032 245 0.94 0.197 0.53 0.20 0.069 0.128
250 0.57 0.101 0.52 0.20 0.070 0.031 250 0.92 0.198 0.52 0.20 0.070 0.128
255 0.56 0.101 0.52 0.20 0.071 0.030 255 0.91 0.199 0.52 0.20 0.071 0.127
260 0.55 0.102 0.52 0.20 0.073 0.029 260 0.90 0.200 0.52 0.20 0.073 0.127
265 0.55 0.102 0.52 0.20 0.074 0.028 265 0.88 0.200 0.52 0.20 0.074 0.126
270 0.54 0.103 0.52 0.20 0.075 0.027 270 0.87 0.201 0.52 0.20 0.075 0.126
275 0.53 0.103 0.52 0.20 0.077 0.027 275 0.86 0.202 0.52 0.20 0.077 0.125
280 0.52 0.104 0.52 0.20 0.078 0.026 280 0.85 0.203 0.52 0.20 0.078 0.125
285 0.52 0.104 0.52 0.20 0.079 0.025 285 0.84 0.204 0.52 0.20 0.079 0.125
290 0.51 0.105 0.52 0.20 0.081 0.024 290 0.83 0.205 0.52 0.20 0.081 0.124
295 0.50 0.105 0.52 0.20 0.082 0.023 295 0.82 0.206 0.52 0.20 0.082 0.124
300 0.50 0.105 0.52 0.20 0.083 0.022 300 0.81 0.207 0.52 0.20 0.083 0.123
305 0.49 0.106 0.52 0.20 0.085 0.021 305 0.79 0.207 0.52 0.20 0.085 0.123
Mod. FAA Minor Storage Volume (cubic ft.) = 2,177 Mod. FAA Major Storage Volume (cubic ft.) = 5,704
Mod. FAA Minor Storage Volume (acre-ft.) = 0.0500 Mod. FAA Major Storage Volume (acre-ft.) = 0.1310
Determination of MAJOR Detention Volume Using Modified FAA Method
(For catchments less than 160 acres only. For larger catchments, use hydrograph routing method)
(NOTE: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended)
UDFCD DETENTION BASIN VOLUME ESTIMATING WORKBOOK Version 2.34, Released November 2013
Determination of MINOR Detention Volume Using Modified FAA Method
DETENTION VOLUME BY THE MODIFIED FAA METHOD
2601 Canton Court
Basin 2
UD-Detention_v2.34.xls, Modified FAA 6/21/2016, 12:56 PM