HomeMy WebLinkAboutDrainage Reports - 07/15/20011
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PROPUTr OF
FORT OOLIJl s UTUXMS
FINAL DRAINAGE REPORT
FOR .
RICHIE'S EXPRESS CARWASH
FOOTHILLS BASIN
PREPARED FOR
THOMAS FRANK
JUNE 4, 2001
PREPARED BY
STEWART &.ASSOCIATES
103 SOUTH MELDRUM STREET
P.O. BOX 429
FORT COLLINS, CO 80522
TEL. 970-482-9331
FAX. 970-482-9382
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TABLE OF CONTENTS
1-2
Text
3
Vicinity Map
4-10
Stormwater Runoff Calculations
11-14
Erosion Control Calculations
15-21
Water Quality Calculations
22
Letter from C.D.O.T
23-24
Spillway Design
Pocket
Drainage Plan
L
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STEWART&ASSOCIATES
' Consulting Engineers and Surveyors
June 4, 2001
'
Mr. Basil Harridan
Stormwater Utilities
City of Fort Collins
P.O. Box 580
'
Fort
Collins, CO 80522-0580
' Dear Basil,
The following is the final drainage report for Richie's Express Carwash which is in the Foothills Drainage
' Basin. It is situate in the Southeast 1/4 of Section 26, Township 7 North, Range 69 West of the Sixth P.M., Fort
Collins, Colorado. The area of the site is 1.5777 acres.
' The site is at 3141 South College Avenue and the existing building is occupied by The Tire Shoppe.
Their building will be demolished and a new carwash center will be constructed on the site.
' The site is bounded on the North by an existing bank building, on the East by South College Avenue,
on the South by the Larimer County No. 2 Canal and on the West by Foothills Parkway.
The existing site has 94.6% impervious surface and the proposed site has 68.1 % impervious surface.
' The reduction of impervious surface reduces the two year runoff rate from 3.17 c.f.s. to 2.06 c.f.s. which is a 35%
reduction. The 100 year runoff rate is reduced from 14.28 c.f.s. to 9.55 c.f.s. which is a 33.1% reduction.
Therefore there will not be any on -site stormwater detention required.
There are five developed sub -basins on the site. Sub -Basin I is a 0.28 acre area that will drain
Northwesterly to the Southeasterly Foothills Parkway curb and gutter. Its two year runoff rate is 0.35 c.f.s. and
its 100 year runoff rate is 1.63 c.f.s..
Sub -Basin H is a 0.93 acre area that drains Northeasterly to the existing Frontage Road. Its two year
' runoff rate is 1.48 c.f.s. and its 100 year runoff rate is 7.01 c.f.s.. Theresa Jones of Colorado Department of
Transportation told me that as long as the stormwater runoff was not being increased, it could continue to flow
in the existing gutter and pan in the Frontage Road. The 100 year runoff from Sub -Basins I, II, IV & V which
flows to the Frontage Road is being decreased from 14.28 c.f.s. to 9.55 c.f.s..
Sub -Basin III is the Larimer County No. 2 Canal and has an area of 0.22 acres. There is no stormwater
' nmoff from this site that discharges into the Canal. The Northerly bank of the Canal is higher than the site. This
area of the canal develops a two year runoff rate of 0.2� c.f.s. and a 100 year runoff rate of 1.01 c.f s. from its
own area. ?'
' Sub -Basin IV is the parking area that will be deeded to the bank. Its area is 0.06 acres. The two year
runoff rate is 0.16 c.f.s. and its 100 year runoff rate is 0.60 c.f.s.. The runoff will flow to Foothills Parkway in
' a 2.0 foot concrete pan. The existing 6" C.M.P. culvert carries historic runoff from the historic site to the bank
property. The only runoff from the developed site that flows onto the bank property is Sub -Basin IV flows.
Sub -Basin V is the area that flows into the College Avenue curb and gutter. The area of Sub -Basin V
' is 0.09 acres. The two year runoff rate is 0.07 c.f.s. and the 100 year runoff rate is 0.31 c.f.s.. The runoff flows
North in the West gutter of College Avenue to an existing curb inlet at the low point of College Avenue which
is at the Northeast comer of the Mourning Subdivision. Theresa Jones of Colorado Department of Transportation
' has approved this runoff to continue in the College Avenue right-of-way.
James H. Stewart and Associates, Inc.
' 103 S. Meldrum Street • P.O. Box 429 • Ft. Collins, CO 80522
970/482-9331 • Fax 970/482-9382
' The 100 year runoff from the site, excluding Sub -Basin III which is the Canal, is being decreased from
the historic runoff rate of 14.28 c.f.s. to the developed runoff rate of 9.55 c.f.s..
' The runoff from Sub -Basin I flows Northeasterly in the Foothills Drive gutter to the corner of Foothills
Parkway and the Frontage Road. The runoff from Sub -Basin II flows North from the site in the East and in the
' West gutters of the Frontage Road The West gutter runoff merges with the Foothills Parkway runoff and flows
North across Foothills Parkway in a concrete pan and then Northerly in the West gutter of the Frontage Road to
an existing curb inlet at the existing 48 inch storm drain 230 feet North of the centerline of Foothills Parkway.
' The East gutter runoff in the Frontage Road flows across the Frontage Road to the to the West gutter then flows
North to an existing curb inlet at the existing 48 inch storm drain 230 feet North of the centerline of Foothills
Parkway.
' EROSION CONTROL:
' The site is in the moderate wind and rainfall erodibility zones.
The site is presently nearly all paved. It is recommended to leave a substantial area of the existing
' asphalt for a staging area for the construction of the carwash. At the beginning of the construction of the curb
and gutter, the remainder of the existing asphalt can be removed. This will allow the site to not be disturbed for
a long period of time before the new paving is started. A silt fence will be placed along the North property line
' to prevent any silt from entering the bank property, and straw bales will be placed at the water quality area before
the structure is constructed.
The water quality extended detention requirement was waived by the City of Fort Collins at the concept
' review meeting and then that decision was rescinded. A water quality extended detention pond will be placed at
the Northeast comer of the site for Basin II. Another water quality extended detention pond will be placed in the
Southwest comer of the site for Basin I. Basin III will not have extended detention since it is all ditch area and
' no other area drains into the ditch. Basin IV will be owned by the Compass Bank and it is totally hard surfaced.
Basin V is all sidewalk or sod and only has an area of 0.09 acres.
The grading and drainage plan is enclosed as a part of this report. The historic and developed runoff
calculations are also a part of this report.
' This drainage report and the design of the drainage system are in compliance with the City of Fort Collins
Storm Drainage specifications and criteria. If you have questions regarding this report, please can
' Sincerely,
��A.
rE
Rerfoaichard A. Ruthrd, P.E. & L. * ? 5028
RAWmeh
(3)
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CONSTRUCTION SEQUENCE
IOJECT: RICMIES ExP2E5t CA2WAs ,fu8D/V[I/o,v
STANDARD FORM C
;EQUENCE FOR 302061 ONLY COMPLETED BY: ,- 4 e- DATE: J A v. Z4, tool
Licata by use of a bar line or symbols when erosion control measures will be installed.
lajor modifications to an approved schedule may require submitting a new schedule for
1roval by the City Engineer.
ZooI YEAR
Holm
3T AA S I A I S t o I •v I D
BLOT GRADING
�D EROSION CONTROL
Soil Roughening
Perimeter Barrier
Barriers
'Additional
Vegetative Methods
Soil Sealant
' Other
NFALL EROSION CONTROL
STRUCTURAL:
Sediment Trap/Basin
Inlet Filters
'Straw Barriers
Silt Fence Barriers
Sand Bags
Soil Preparation
'Bare
Contour Furrows
Terracing
Paving
'Asphalt/Concrete
Other
VEGETATIVE:
Permanent Seed Planting
Mulching/Sealant
'Temporary Seed Planting
Sod Installation
Nettinge/Mate/Blankets
' Other
J.
,UCTURESs INSTALLED BY MAINTAINED BY
ETATION/MULCHING CONTRACTOR
SUBMITTED APPROVED BY CITY OF FORT COLLINS ON
MARCH 1991 8-16 DESIGN CRITERIA
02)
RAINFALL PERFORMANCE STANDARD EVALUATION
---------------------------------------------------------------------
PROJECT: g is wiai Ex PK 6JJ C 4 P-W AJry SO 6 . STANDARD FORM A
COMPLETED BY: 4 A. je- DATE: J<., Z¢ zoos
I------------------------------------------------------------- >-------
DEVELOPEDIERODIBILITY1 Asb I Lsb• Ssb Lb Sb PS
SdBBASIN ZONE (ac) (ft) (A) .I(feet) I (p) 1 (o)
----------------- ------------ -------I-------I-------
TorAL MopE2Arc 11,sBA,l 4�s o•s7% 47sr7i Cs7% 1 73,1%
--- -- ----
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)I/SF-A:1989
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EFFECTIVENESS CALCULATIONS
PROJECT: Xs&Aoi tr Expica-v Coe UJAXR TUS 0104fio a STANDARD FORM B
COMPLETED BY: e- AAt DATE:
Erosion Control
C-Factor
P-Factor
Method
Value
Value
Comment
ex 1ST/A)& A-VpfYAcj
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CALCULATIONS
II wm c=�o01x 6,3z)a-.(aaIX0.at)+- (lox /L¢
W ra P = o,sD.X 0.60 = 0.40
(0.6,42x.0.40)]x/00 = 73,51/o
0>< ? 734-°/6
STEWARTMSSOCIATES
Consulting Engineers and Surveyors
Mr. Basil Hamdan
Stormwater Utilities
City of Fort Collins
P.O. Box 580
Fort Collins, CO 80522-0580
Dear Basil,
The following is the cost estimate for the erosion control measures for Richie's Express
Car Wash Subdivision
1. Silt Fence, 250 L.F. @ $3/L.F. $750.00
2. Extended Detention Pond $500.00
3. Straw Bales $100.00
Total Estimate Items 1-3 $1,350.00
4. Reseeding 1.36 Acres @ $650 per Acre $884.00
Escrow for SITE = $1,350 X 1.5 $2,025.00
If you have any questions regarding this estimate, please call.
Sincerely,
Richard A. Rutherford, P.E. & L.S.
RAR/bac
James H. Stewart and Associates, Inc.
103 S. Meldrum Street • P.O. Box 429 • Ft. Collins, CO 80522
970/482-9331 9 Fax 970/482-9382
STEWART&JkSSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521
Consulting Engineers and Surveyors PH. 482-9331 FAX 482-9382
By: )e 4 k2. Date: -/ / / q /0 / Client: T * o An A-r F,e A Aj Sheet No. 1T of
Project: c N lEf A—:- x 12 ;? gr, rp A e- W A H
Subject: A -TE a(I,+L-1-ry Ex-reFA)c>9c> -rr-- Aj 7-/o A) AS,,VEX 7r
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UDFCD
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DRAINAGE CRITERIA MANUAL (V. 3)
-B- -._ .- ) - T'r- -
STORMWATER QUALITY MANAGEMENT
E.xtended
10-HoL
De
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i time
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Drain
Is (W
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Percent Impervious Area in Tributary Watershed
Source:Urbancs, Guo, Tucker (1989)
O
Note: Watershed inches of runoff shall appl to the
entire watershed tributary to the B pl�Faclity.
FIGURE 5-1. WATER QUALITY CAPTURE VOLUME (WQCV)
, _ DRAINAGE CRITERIA MANUAL (V. 3)
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EXAMPLE: DWO - 4.5 ft
VNIA
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SOLLI ION: Required Area pe
Row - 1.75 in. 2
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1 Required Area per Row (in.2 )
Source: Douglas County Storm Drainage and Technical Criteria;1986.
1 FIGURE 5-3. WATER QUALITY OUTLET SIZING: DRY EXTENDED DETENTION
BASIN WITH A 40-HOUR DRAIN TIME OF THE CAPTURE VOLUME
9-1-1992
UDFCD
■
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STEWART&ASSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
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By: )e- A 6� Date: 4-107101 Client: Tfiom.A.s F2,4 A,, K
SheetNo. )B of
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Subject: IA),4-rl--- fe 0 uA z-1 ry — E T E r O— B As i1v
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DRAINAGE CRITERIA MANUAL (V. 3)
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0
0..
m
a
m
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c
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1
1
9-1-1992
1
UDFCD
STORMWATER QUALITY MANAGEMENT
i
t•
Extenc
10-HOL
ed De
r Draii
entior
i time
Basi
(Dry)
D
1
tenti
-Hour
n Pon
Drain
Is (Wet)
Time
"00-
u iu zu 30 40 50 so 70 80 90 100
Percent Impervi8us Area in Tributary Watershed
Source: Urbancs, Guo, Tucker It 9f19)
N
O
Note: Watershed inches of runoff shall a'ppI to the
entire watershed tributary to the SguVaciliry. "
FIGURE 5-1. WATER QUALITY CAPTURE VOLUME (WQCV)
' _ DRAINAGE CRITERIA MANUAL (V. 3)
1
cD
co 0.6(
m
mo.4c
E
m
9
c 0.2(
T
7
d
0.1(
3
o.oE
o.N
0.oi
Cz 0)
STRUCTURAL BMPs
0 yve
PA
INEVINW021,
WQCV . 2.1 acre-feet
SOLUTION: Required Area er
T Row . 1.75 in.f
PAF
p
.�
min
�Emmimmi
VZOENWAN
0.01
0• 0.20 0.40 0.60 1.0 2.0 4.0 6.0
Required Area per Row (n.2 )
Source: Douglas County Stomr Drainage and Technical Criteria,1986.
FIGURE 5-3. WATER QUALITY OUTLET SIZING: DRY EXTENDED DETENTION
BASIN WITH A 40-HOUR DRAIN TIME OF THE CAPTURE VOLUME
9-1-1992
VDFCD
C21)
EXTENDED DETENTION POND
VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.)
' 2. FOR THE REMAIMDER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2)
VOL. = DEPTH/3 (A +(AB) ^ .5 + B) FOR: Uniform Sides sec.(9.2)
3. HWL=(VOL.REO.—VOL.LOW CUML)*3/(AREA LOW+AREA HIGH+(low area*high area)
29 55 HWLPOND
ORIFICE SIZING
f �zzj
i
1 M , 2001
1
1 Mr. David Stringer
Engineering Department
City of Fort Collins
1 P.O. Box 530
Fort Collins, CO 80522-0580
1
1
1
1
1
1
1
1
1
Dear Dave,
This is regarding the proposed RICHIE'S EXPRESS CARWASH SUBDIVISION at 3141
South College Avenue.
Dick Rutherford at Stewart and Associates, Inc. has given me a copy of the Grading,
Drainage and Erosion Control Plans. The existing site has the Tire Shoppe on it and the proposed
site plan has a significant decrease in hard surface. The proposed sites two-year runoff rate is
decreased by 35.0% and the 100-year runoff rate has a 33.1% reduction.
The existing site and the proposed site have the same drainage pattern. The runoff from most
of the site flows to the Northeast comer of the site and then flows North in the West gutter of the
existing frontage road. The runoff flows across Foothills Parkway in a concrete pan and continues
North to an existing curb inlet near the Southeast corner ofDellenbaugh Chevrolet.
As long as the runoff is not being increased and is not discharging into the College Avenue
gutter and is not changing the drainage pattern, the Colorado Department of Transportation will
approve the proposed drainage plan.
If you have any questions regarding this matter, please call.
Since ly,
IG
Tess Jones
Colorado I
of Transportation
L G31
EMERGENCY. SPILLWAY DESIGN
Weir Equation Q = C L (H) ^ 3/2
Q (cfs), C (weir coefficient), L (crest length, feet), H (energy head, feet)
12 = Weir Length L in feet
3.1 = Weir Coefficient
Weir Shape Broadcrested
Design Flow 1.63 (cfs)
Depth of
flow ft
Flow Over Weir
(cfs)
0.10
1.18
0.11
1.36
0.12
1.55
0.13
1.74
0.141
1.95
0.15
2.16
0.20
3.33
0.30
6.11
0.40
9.41
0.50
13.15
I?!
WS.E o 29. Sn
B�1Slti=.J1
EMERGENCY SPILLWAY DESIGN
Weir Equation 0 = C L (H) ^ 3/2
0 (cfs), C (weir coefficient), L (crest length, feet), H (energy head, feet)
20 = Weir Len th L in feet
3.1 = Weir Coefficient
Weir Shape Broadcrested
Design Flow 7.01 (cfs) 100 YEAR
Depth of
flow (ft)
Flow Over Weir
(cfs)
0.10
1.96
0.20
5.55
0.22
6.40
0.23
6.84
0.24
7.29
0.251
7.75
0.30
10.19
0.35
12.84
0.40
15.68
0.50
21.92
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LARIMER COUNTY CANAL N0.2 a4SIN I8
:I 0.22 ACRES
NOTES
1. LAIl tI of ladder of aedhaQ on aefimufaa and M
I limier will be Cefe,nirmd rby
9,a coy Inspector.
P +J.faO sawn lace o)ae�snrp aapneu enN oe 4rt unapt
ro, the Constrvc(Ton of me
IWash and deal propanaa cw add 9ufha conafrvNon,a
nec Al that b,ro fM nmaini,g
aapran w YmoYe
a.WK�,P
a }YR= 0P
0 room- t.or na
WATER QUALITY SUMMARY
WATER DDALITY CAPTURE VOLUME = 941 CF
W.SE.V = 28.J8
SCALE - 1"�10'
.a
YO 0
20 40 BO
LYdIF1aC SLATE - iEET
-a.;
1.y
LEGEND
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City of Fort Collins, Colorado
2
UTILITY PLAN APPROVAL
APPROVED:
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4 a 6