HomeMy WebLinkAbout2601 CANTON CT. - PDP/FDP - FDP160033 - REPORTS - 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
February 10, 2017
Job Number 347-09
ii
February 10, 2017
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
iii
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 ..........................................................................................2
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 ..................................................................................................3
3.4 Hydraulic Criteria ....................................................................................................3
3.5 Four Step Four Step Process to Minimize Adverse Impacts of Urbanization .........3
4. DRAINAGE FACILITY DESIGN
4.1 General Concept ......................................................................................................4
4.2 Specific Flow Routing .............................................................................................5
4.3 Drainage Summary ..................................................................................................5
5. CONCLUSIONS
5.1 Compliance with Standards ....................................................................................6
5.2 Drainage Concept ....................................................................................................6
6. REFERENCES ....................................................................................................................7
APPENDICES
A Vicinity Map
B Hydrologic Computations
C Hydraulic Computations
D Water Quality Pond Calculations
E LID Information, BMP Schedule & Cost Estimate
F Erosion & Sediment Control Report
1 | Page
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 and currently does not
discharge runoff. The site will be filled and shaped to drain 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 bio swale (with underdrain) and then into
water quality pond on the adjacent lot. This pond will be contained in a drainage
easement that will be dedicated to the City with this development proposal. The water
will then discharge into Midpoint Drive and be conveyed to the Prospect Ponds where
detention for this site will occur. An easement from Natural Areas will be obtained to
allow for detention in these ponds.
2 | Page
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. The proposed LID treatment will be a bio swale located on the
southeast edge of the site.
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 bio
swale on the southeast side of the site and then routed to a proposed water quality pond
on the adjacent property. A small portion of the site will flow to the northeast and into
Canton Court without entering the water quality pond. The water quality pond will
release runoff into Midpoint Drive which will convey the water southeast to Sharp Point
Drive and north into the Prospect Ponds via inlet and storm pipe. The Prospect Ponds
will provide detention for this site therefore no onsite detention is being provided for with
3 | Page
this design. An easement will be obtained from Natural Areas to allow for detention in
the Prospect Ponds.
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.
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 bio swale. A perforated pipe will collect the runoff and convey it to the water
quality pond. The water quality pond will release to Midpoint Drive via an outlet
structure and storm pipe 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 through the drive entrance to Canton Court.
Detention and water quality extended detention are required for this site. Detention is
proposed to be provided in the Prospect Ponds and water quality will be provided in a
pond on the adjacent lot. The water quality 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 4895.50. The pond will discharge through a new
drainage pipe to the curb in Midpoint Drive. This runoff will then be routed to the
existing Prospect Pond on the east side of Sharp Point Drive.
3.5 Four Step Four Step Process to Minimize Adverse Impacts of Urbanization
Step 1. Employ Runoff Reduction Practices – reduction of runoff peaks, volumes, and
pollutant loads as the site is developed by implementing Low-Impact Development (LID)
facilities including:
Increase time of concentration by routing flows around the building and
increasing the length of the flow path.
Routing runoff from the proposed site into a bio-swale to promote infiltration and
biological uptake.
Routing flows through filter material in the bio swale to increase time of
concentration, promote infiltration and provide initial water quality.
4 | Page
Step 2. Implement BMPs That Provide a Water Quality Capture Volume with Slow
Release - The efforts outlined in Step 1 will facilitate the reduction of runoff; however,
this development will also require water quality. Runoff will be routed through the bio-
swale and then to a pond that will provide water quality extended detention prior to
release into the street to not only reduce the amount of runoff generated from the site
through infiltration, but also treat the runoff prior to releasing it from the site.
A table showing the Low Impact Development practices being utilized within this project
is provided in Appendix E.
Step 3. Stabilize Streams - There are no major drainageways in or near this site
therefore Step 3 it not directly applicable this project. However, this project will pay
stormwater development fees and monthly stormwater utility fees which contribute to the
City’s ongoing efforts to attain stream stability where and as needed.
Step 4. Implement Site Specific and Other Source Control BMPs - This step applies
to covering storage/handling areas and spill containment and control. Vehicle
maintenance will be completed off site to prevent potential spills of vehicle fluids. Any
handling of chemicals will be completed inside the building and will be handled per the
applicable MSDS (material safety data sheet). Spills will be contained immediately and
cleaned up using appropriate absorption materials.
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
bio swale. The flow will percolated into the subsurface material and enter the perforated
pipe. This perforated pipe will convey runoff directly to the water quality pond and, in
an overflow situation, a second pipe is provided to convey the runoff to the water quality
pond.
5 | Page
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 Canton Court via the drive entrance. 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 bio swale.
The runoff from this basin will flow to the south and east and into the bio swale. A
perforated pipe will collect the flow and convey it to the offsite water quality pond. If the
perforated pipe becomes clogged or is over capacity, the water will flow in the bio swale
to the secondary pipe and be conveyed to the water quality 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 provides water quality extended detention and will release into a curb opening in
Midpoint Drive to the southwest of this site.
LID features have been incorporated in the design of the overall site. The site plan
currently shows LID measures proposed with the development plan consisting a bio
swale. Please see the LID Design Information provided in Appendix D.
4.3 Drainage Summary
All runoff from this site will be safely conveyed via surface flow and piping to the water
quality 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 bio swale, the water quality pond, the concrete pan in
6 | Page
the water quality pond and the pond outlet structure will be maintained by the owner of
Lot 11 and any other properties that will contribute runoff to the pond.
5. CONCLUSIONS
5.1 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.
5.2 Drainage Concept
The proposed drainage concepts presented in this report and on the construction plans
adequately provide for conveyance of runoff to the water quality area. 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.
7 | Page
6. 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 | Page
APPENDIX A
VICINITY MAP
B | Page
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: 2/10/2017
Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria
Recommended % Impervious from Urban Storm Drainage Criteria Manual
% Runoff
Impervious coefficient
C
Streets, parking lots (asphalt): 100% 0.95
Sidewalks: 90% 0.95
Recycled Asphalt: 40% 0.40
Roofs: 90% 0.95
Lawns (flat <2%, heavy soil): 0% 0.20
SUBBASIN TOTAL TOTAL ROOF PAVED SIDEWALK REC. ASPHALT LANDSCAPE % RUNOFF
DESIGNATION AREA AREA AREA AREA AREA AREA AREA Impervious COEFF.
(ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C)
1 0.02 1,060 0 354 72 0 634 40% 0.50
2 0.99 43,190 9,000 13,202 1,314 11,718 7,956 63% 0.66
TOTAL 1.02 44,250 9,000 13,556 1,386 11,718 8,590 62% 0.66
Historic Lot 11 1.02 44,250 0 0 0 0 44,250 0% 0.20
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
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: 2/10/2017
2-yr storm Cf = 1.00
FINAL REMARKS
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 0.02 0.50 26 1.0 5.5 26 6.5 0.016 5.1 0.08 5.6 52 10.3 5.6 To Canton Ct
2 2 0.99 0.66 46 1.0 5.3 380 0.5 0.016 1.4 4.46 9.8 426 12.4 9.8 To bioswale
TOTAL 1.02 0.66 46 1.0 5.4 380 0.5 0.016 1.4 4.46 9.8 426 12.4 9.8
1 Historic Lot 11 1.02 0.20 172 1.6 18.2 131 0.7 0.030 0.9 2.51 20.7 303 11.7 11.7 Historic
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 minutes
TIME (ti)
TRAVEL TIME / GUTTER OR CHANNEL FLOW
(tt)
tc CHECK
(URBANIZED BASIN)
STANDARD FORM SF-2
TIME OF CONCENTRATION - 2 YEAR
SUB-BASIN DATA INITIAL /OVERLAND
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: 2/10/2017
100-yr storm Cf = 1.25
FINAL REMARKS
tc
DESIGN SUBBASIN(s) Area C C*Cf 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 0.02 0.50 0.63 26 1.0 4.3 26 6.5 0.016 5.1 0.08 4.4 52 10.3 5.0
2 2 0.99 0.66 0.83 46 1.0 3.3 380 0.5 0.016 1.4 4.46 7.8 426 12.4 7.8
0 TOTAL 1.02 0.66 0.82 46 1.0 3.4 380 0.5 0.016 1.4 4.46 7.8 426 12.4 7.8
1 Historic Lot 11 1.02 0.20 0.25 172 1.6 17.2 131 0.7 0.030 0.9 2.51 19.7 303 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 minutes
TIME OF CONCENTRATION - 100 YR
STANDARD FORM SF-2
SUB-BASIN DATA
TIME (ti)
INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW
(tt)
tc CHECK
(URBANIZED BASIN)
Flow.xls TOC-100
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
RATIONAL METHOD PEAK RUNOFF
(2-YEAR)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: ppk
DATE: 2/10/2017
2-yr storm, Cf = 1.00
TOTAL REMARKS
Design Tributary A C*Cf 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 0.02 0.50 5.6 2.69 0.0 0.0 To Canton Ct
2 2 0.99 0.66 9.8 1.99 1.3 1.3 To bioswale
0 TOTAL 1.02 0.66 9.8 2.22 1.5 1.5
1 Historic Lot 11 1.02 0.20 11.7 1.65 0.3 0.33 Historic
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)
DIRECT RUNOFF CARRY OVER
Flow.xls Q2
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF
(100-YEAR)
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: ppk
DATE: 2/10/2017
100-yr storm, Cf = 1.25
TOTAL REMARKS
Des. Area A C*Cf tc i Q (100) from Q (100) Q(100)tot
(new) Design
Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
1 1 0.02 0.63 5.0 9.95 0.2 0.15 To Canton Ct
2 2 0.99 0.83 7.8 8.17 6.7 6.71 To bioswale
TOTAL 1.02 0.82 7.8 8.39 7.0 7.0
1 Historic Lot 11 1.02 0.25 11.7 5.67 1.4 1.4 Historic
Q = C iA
Q = peak discharge (cfs)
C = runoff coefficient
I = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
DIRECT RUNOFF CARRY OVER
Flow.xls Q100
C | Page
APPENDIX C
HYDRAULIC CALCULATIONS
Project:
Pipe ID:
Design Information (Input)
Pipe Invert Slope So = 0.0375 ft/ft
Pipe Manning's n-value n = 0.0120
Pipe Diameter D = 12.00 inches
Design discharge Q = 6.70 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 = 7.49 cfs
Calculation of Normal Flow Condition
Half Central Angle (0<Theta<3.14) Theta = 2.07 radians
Flow area An = 0.62 sq ft
Top width Tn = 0.88 ft
Wetted perimeter Pn = 2.07 ft
Flow depth Yn = 0.74 ft
Flow velocity Vn = 10.79 fps
Discharge Qn = 6.70 cfs
Percent Full Flow Flow = 89.45% of full flow
Normal Depth Froude Number Frn = 2.26 supercritical
Calculation of Critical Flow Condition
Half Central Angle (0<Theta-c<3.14) Theta-c = 2.80 radians
Critical flow area Ac = 0.78 sq ft
Critical top width Tc = 0.34 ft
Critical flow depth Yc = 0.97 ft
Critical flow velocity Vc = 8.60 fps
Critical Depth Froude Number Frc = 1.00
CIRCULAR CONDUIT FLOW (Normal & Critical Depth Computation)
2601 Canton Court
Storm pipe between bio swale and water quality pond
Culvert.xls, Pipe 2/10/2017, 4:41 PM
Project:
Pipe ID:
Design Information (Input)
Pipe Invert Slope So = 0.0100 ft/ft
Pipe Manning's n-value n = 0.0120
Pipe Diameter D = 15.00 inches
Design discharge Q = 6.70 cfs
Full-flow Capacity (Calculated)
Full-flow area Af = 1.23 sq ft
Full-flow wetted perimeter Pf = 3.93 ft
Half Central Angle Theta = 3.14 radians
Full-flow capacity Qf = 7.02 cfs
Calculation of Normal Flow Condition
Half Central Angle (0<Theta<3.14) Theta = 2.17 radians
Flow area An = 1.03 sq ft
Top width Tn = 1.03 ft
Wetted perimeter Pn = 2.71 ft
Flow depth Yn = 0.98 ft
Flow velocity Vn = 6.51 fps
Discharge Qn = 6.70 cfs
Percent Full Flow Flow = 95.44% of full flow
Normal Depth Froude Number Frn = 1.15 supercritical
Calculation of Critical Flow Condition
Half Central Angle (0<Theta-c<3.14) Theta-c = 2.30 radians
Critical flow area Ac = 1.09 sq ft
Critical top width Tc = 0.93 ft
Critical flow depth Yc = 1.04 ft
Critical flow velocity Vc = 6.14 fps
Critical Depth Froude Number Frc = 1.00
CIRCULAR CONDUIT FLOW (Normal & Critical Depth Computation)
2601 Canton Court
Water quality pond outlet
Culvert.xls, Pipe 2/10/2017, 4:39 PM
D | Page
APPENDIX D
WATER QUALITY POND CALCULATIONS
WATER QUALITY POND SIZE
LOCATION: 2601 Canton Court
PROJECT NO: 347-09
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design, Inc.
DATE: 2/10/2017
From Urban Storm Drainage Criterial Manual
Use 40-hour brim-full volume drain time for extended detention basin
Required Storage = a * ( 0.91 * I3 - 1.19 * I2 + 0.78 * I )
Water Quality Capture Volume = WQCV = (required storage/12)*(tributary drainage area)
Trib. % Imperv. Req. Storage WQCV req. vol DWQ req. area/row
area from Fig. EDB-2 WQCV *1.2 from Fig. EDB-3
(ac) (in. of runoff) (ac-ft) (ac-ft) (ft) (in2/row)
POND 0.99 63 0.247 0.020 0.024 1.25 0.104
WQ outlet sizing for pond 1
From Figure 5,
for 3/8 in. hole diameter
Area of hole = 0.110 in2
# of columns = 1
Area provided/row = 0.110 in2
Area Required/row = 0.104 in2
Use 1 columns of 3/8" diam holes
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 = 0.000
Water Quality Volume Required = 0.024
Total Volume Required= 0.024
Surface Incremental Total
Stage Area Storage Storage
(ft) (ft2) (ac-ft) (ac-ft)
4893.75 0
4894.0 640 0.001 0.001
4895.0 1,425 0.023 0.024
WQCV 4895.00 1,425 0.000 0.024
4895.50 2,171 0.020 0.045 <==SPILLWAY ELEV
4896 4896.0 2 2,917 0 0.049 0 0.073
4896.5 3,374 0.036 0.109
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 0.5 ft flow depth, thus H = 0.5 ft
Size the spillway assuming that the pond outlet is completely clogged.
Q (100) = 6.7 cfs
Spill elev = 4895.50 ft 100 yr WSEL = 4895.0 ft
Top of berm elev.= 4896.50
Weir length required:
L = 7 ft
Use L = 10 ft
v = 0.96 ft/s
E | Page
APPENDIX E
LID INFORMATION
BMP SCHEDULE & COST ESTIMATE
2/10/2017
Calculation for Required LID Treatment
New Impervious Area 23942 sq. ft.
Required Minimum Impervious Area to be Treated (75%) 17956.5 sq. ft.
Impervious Area Treated by LID Treatment Method #1 (bio
swale) 37730 sq. ft.
Total Impervious Area Treated 37730 sq. ft.
Max run on ratio is 10:1, required bio swale area 3773 sq. ft.
Area of bio swale 3710 sq. ft.
2601 Canton Court
LID Summary Table
Project: Disturbed Acres: 1.27
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 $220.00 $220.00
each 1 $1,500.00 $1,500.00
each 1 $1,200.00 $1,200.00
each 0 $210.00 $0.00
Sub-Total: $6,965.00
1.5 x Sub-Total: $10,447.50
Amount of security: $10,447.50
Total Acres x Price/acre: $1,524.00
$1,200.00 Sub-Total: $1,524.00
1.5 x Sub-Total: $2,286.00
Amount to Re-seed: $2,286.00
Minimum escrow amount: $3,000.00
Erosion Control Escrow: $10,447.50
Erosion and Sediment Control Escrow/Security Calculation
for The City of Fort Collins
BMP Amount
Silt Fence
Concrete Washout
Inlet Protection
Reseeding Amount
Rock Berm
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
2/10/2017 3:14 PM \\Nstar\projects\347-09 Canton Court\drainage\ErosionEscrow.xls
F | Page
APPENDIX F
EROSION & SEDIMENT CONTROL REPORT
i | Page
EROSION & SEDIMENT CONTROLS
1.0 Written Analysis
An Erosion and Sediment Control Plan is included herewith. It should be noted, however,
that any such Erosion and Sediment Control Plan serves only as a general guide to the
Contractor. Staging and/or phasing of the BMPs depicted, and additional or different
BMPs from those included may be necessary during construction, or as required by the
authorities having jurisdiction.
It shall be the responsibility of the Contractor to ensure erosion control measures are
properly maintained and followed. The Erosion and Sediment Control Plan is intended to
be a living document, constantly adapting to site conditions and needs. The Contractor
shall update the location of BMPs as they are installed, removed or modified in
conjunction with construction activities. It is imperative to appropriately reflect the
current site conditions at all times.
The Erosion and Sediment Control Plan shall address both temporary measures to be
implemented during construction, as well as permanent erosion control protection. Best
Management Practices from the Volume 3, Chapter 7 - Construction BMPs will be
utilized. Measures may include, but are not limited to, silt fencing along the disturbed
perimeter, gutter protection in the adjacent roadways and inlet protection at proposed
storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures,
designated concrete washout areas, dumpsters, and job site restrooms shall also be
provided by the Contractor.
Grading and Erosion Control Notes can be found on Sheet 2 of the Utility Plans. In
addition to this report and the plan sheets, the Contractor shall be aware of and adhere to
the applicable requirements outlined all Development Agreements pertaining to this
property. Also, the Site Contractor for this project will be required to secure a
Stormwater Construction General Permit from the Colorado Department of Public Health
and Environment (CDPHE), Water Quality Control Division - Stormwater Program,
before commencing any earth disturbing activities. The Contractor shall also develop a
comprehensive Storm Water Management Plan (SWMP) conforming to applicable
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requirements including descriptions of the ongoing activities, inspections and
maintenance of construction BMPs.
•
The site is approximately 1.02 acres all of which will undergo earthmoving operations.
The existing site has existing ground cover (volunteer grasses and weeds) on approximate
45% - 50% of the site as the site has been historically used for storage of materials and
vehicles for adjacent properties.
Runoff from this site currently does not discharge to the offsite as this site is in a low area
with all adjacent sites being raised (filled) upon development. With the proposed
development, this site will also be filled and sloped to drain to the southeast. The runoff
will then enter Midpoint Drive and be conveyed southeast to Sharp Point Drive, then
north to a low point where it will enter the City of Fort Collins Natural Areas ponds
(Prospect Ponds) via an inlet and storm pipe. Prospect Ponds discharge into the Cache la
Poudre River on the east side of the ponds.
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 bio 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.
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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.
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.
2.0 SWMP contact information
Permit holder:
Name:
Address:
Phone Number:
Email Address:
Appointed agent:
Name:
Address:
Phone Number:
Email Address:
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3.0 Identification and location of all potential pollution sources
Potential Pollutant Source Activity Potential Pollutant
Generated
Applicable to
this project
Control Measure
Disturbed Areas Sediment X Silt Fence, Rock Socks
Soil stockpiles Sediment X Silt Fence, Rock Socks
Travel to adjacent public streets Tracked sediment X Tracking Pad, street sweeping
Contaminated soils Sediment, chemicals Possible Remove contaminated soils
from site **
Loading and unloading chemicals Chemicals
Unloading of building materials Trash, debris X Trash dumpsters, Waste
Management Firm **
Outdoor storage of chemicals Chemicals
On site equipment maintenance Oil, grease
On site equipment fueling Diesel, gasoline X Containment berm **
Dust generating activities Particulates, sediment X Water truck
Use of fertilizer, pesticides, herbicides Fertilizer, pesticides
Use of detergents, solvents, oils Detergents, solvents, oil X
If spilled, remove
contaminated soils from site
**
Waste dumpsters, waste piles Chemicals, trash, debris X Waste Management Firm
Concrete washout Concrete, sediment, wash
water X
Remove hardened concrete,
dispose of offsite **
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 Waste Management Firm
** Refer to Section 1.5.2 for additional Materials Handling & Spill Prevention BMP
4.0 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.
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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.
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.
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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.
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
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5.0 BMP Implementation
5.1 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.
5.2 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
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5.3 Dedicated Asphalt or Concrete Batch Plant:
Not proposed with this development
5.4 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.
5.5 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.
5.6 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.
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5.7 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.
6.0 Soil Amendments, Permanent Seeding & Mulching
6.1 Soil Amendments
Soil in the bio swale shall be amended per the City of Fort Collins Bioretention Sand
Media Specifications found at:
http://www.fcgov.com/utilities/img/site_specific/uploads/Bioretention_Sand_Media_Specs.pdf
Soil treatment in the water quality area will be to spread imported or stockpiled topsoil to
a minimum depth of four inches over areas to be planted.
6.2 Permanent Seeding
The following seed mix shall be applied at the rates indicated in the bioswale and in the
water quality pond. Other landscaped areas on site shall be treated per the landscape plan.
Mulch shall be applied after seeding as the notes indicate below.
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Drill seed specified mix in two passes, each at right angles to each other. Drill half of the
seed in each pass. If areas are too wet or steep to drill seed, broadcast seed in two
opposite directions. Restore fine grade after seeding, and cover seed to depth of 1/4 inch
by raking or dragging. Firm seeded areas with a roller weighing maximum of 100 lbs. per
foot of width. Ground cover shall be considered established when 70% of the seed has
been germinated. At the point that the seed is considered established, the temporary
erosion control measures may be removed.
6.3 Mulching
All planted areas should be mulched preferably immediately following planting, but in no
case later than 14 days from planting. Mulch conserves water and reduces erosion. The
most common type of mulch used is hay or grass that is crimped into the soil to hold it.
However, crimping may not be practical on slopes steeper than 3:1. The following
guidelines should be followed with mulching:
• Only weed-free and seed-free straw mulch should be used (grass hay often
contains weedy exotic species). Mulch should be applied at 2 tons/acre and
adequately secured by crimping, tackifier, netting, or blankets.
• Crimping is appropriate on slopes of 3:1 or flatter and must be done so as to
tuck mulch fibers into the soil 3 to 4 inches deep.
• Tackifier or netting and blankets anchored with staples should be used on slopes
steeper than 3:1.
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• Hydraulic mulching may also be used on steep slopes or where access is limited.
Wood cellulose fibers mixed with water at 2,000 to 2,500 pounds/acre and
organic tackifier at 100 pounds per acre should be applied with a hydraulic
mulcher.