HomeMy WebLinkAboutKINGDOM HALL - ODP - 18-05A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTI
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City of Fort Collins -
Rainfall Intensity -Duration -Frequency Table
for using the Rational Method
(5 minutes - 30 minutes)
Figure 3-1a
Duration
(minutes)
2-year
Intensity
in/hr
10-year
Intensity
in/hr
100-year
Intensity
in/hr
5.00
2.85
4.87
9.95
6.00
2.67
4.56
9.31
7.00
2.52
4.31
_8.80
8.00
2.40
4.10
8.38
9.00
2.30
3.93
.8.03
10.00
2.21
3.78
7.72
11.00
2.13
3.63
7.42
12.00
2.05
3.50
7.16
13.00
1.98
3.39
6.92
14.00
1.92
3.29
6.71
15.00
1.87
3.19
6.52
16.00
1.81
3.08
6.30
17.00
1.75
2.99
6.10
18.00
1.70
2.90
5.92
19.00
1.65
2.82
5.75
20.00
1.61
2.74
5.60
21.00
1.56
2.67
5.46
22.00
1.53
2.61
5.32
23.00
1.49
2.55
5.20
24.00
1.46
2.49
5.09
25.00
1.43
2.44
4.98
26.00
1.40
2.39
4.87
27.00
1.37
2.34
4.78
28.00
1.34
2.29
4.69
29.00
1.32
2.25
4.60
30.00
1.30
2.21
4.52
No Text
APPENDIX D
FIGURES AND TABLES
9
Emergency Overflow Spillway Sizing
LOCATION: Kingdom Hall of Jehovahs Witness
PROJECT NO: 242-01
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COMPUTATIONS BY: ppk
DATE: 4/3/05
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Equation for flow over weir _
top of berm
54
Q = CLH'" it
spill elevation
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where C = weir coefficient = 3.1 L �
�—
H =overflow height
0
100 YP W$�L
L = length of the weir
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The pond has a spill elevation 0.0 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.
Qioo = 13.90 cfs
Spill elev = 4951.00 ft 100 yr WSEL = 4950.35 ft
Min top of berm elev.= 4951.50
Weir length required:
L = 12.7 ft
'
Use L = 24 ft (width of entry drive)
v = 0.99 ft/s
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Detention Pond Outlet Sizing
(100 yr event)
LOCATION: Kingdom Hall of Jehovahs Witness
PROJECT NO: 242-01
COMPUTATIONS BY: ppk
SUBMITTED BY: North Star Design, Inc
DATE: 4/3/05
Submerged Orifice Outlet:
release rate is described by the orifice equation,
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Q. = C.Ao sgrt( 2g(h-E.))
where Qo = orifice outflow (cfs)
Co = orifice discharge coefficient
g = gravitational acceleration = 32.2 ft/s
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Ao = effective area of the orifice (fe)
Eo = greater of geometric center elevation of the orifice or des HGL (ft)
h = water surface elevation (ft)
Q,,,,x = 0.76 cfs
outlet pipe dia = D = 12.0 in
Invert elev. = 4947.65 ft
Ea = 4947.82 ft
'
h = . 4950.35 ft - 100 yr WSEL
Co = 0.68
solve for effective area of orifice using the orifice equation
Ao = 0.088 fe
= 12.6 in
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orifice dia. = d = 4.01 in
Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering)
d/D= 0.33
kinematic viscosity, v = 1.22E-05 ftZ/s
Reynolds no. = Red = 4Q/(pdv) = 2.38E+05
Co = (K in figure) = 0.68 check
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Use d = 4.00 in
A o = 0.087 ft ' = 12.57 in 2
Q o = 0.76 cfs
DetPond-prelim.xls
LOCATION:
PROJECT NO:
COMPUTATIONS BY:
DATE:
WQCY
100 year WSE'L
STAGE - STORAGE TABLE
(10 & 100-YEAR)
Kingdom Hall of Jehovahs Witness
242-01
ppk
4/3/05
100 yr Detention Volume Required = 0.272
Water Quality Volume Required = 0.039
Total 100 yr Volume Required = 0.310
Stage
(ft)
Surface
Area
(ft)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
4947.65
0
4948.0
1221
0.003
0.003
4948.60
4310
0.036
0.039
4949.0
6369
0.079
0.079
4950.0
7830
0.163
0.242
4950.35
10205
0.072
0.314
4951.0
14615
0.254
0.496
WATER QUALITY POND SIZE
LOCATION:
Kingdom Hall of Jehovahs Witness
PROJECT NO:
242-01
COMPUTATIONS BY:
ppk
SUBMITTED BY:
North Star Design, Inc
DATE:
4/3/05
From Urban Storm Drainage Criterial Manual
Use 40-hour brim -full volume drain time for extended detention basin
Required Storage = a * ( 0.91 * 13 - 1.19 * 12 + 0.78 * 1 )
Water Quality Capture Volume = WQCV = (required storage/12)*(tributary drainage area)
Trib.
% Imperv.
Req. Storage
WQCV
DWo
req. vol
req. area/row
area
from Fig. EDB-2
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WQCV *1.2
from Fig. EDB-3
(ac)
(in. of runoff)
(ac-ft)
(ft)
(ac-ft)
(in 2/row)
POND
1.52
65
0.254
0.032
1.00
0.039
0.242
WQ outlet sizing for pond 1
From Figure 5,
for 9/16 in. hole diameter
Area of hole = 0.249 in
# of columns = 1
Area provided/row = 0.249 in
Area Required/row = 0.242 in .
Use 1 columns of 9/16" diam holes
MINIMUM DETENTION VOLUME REQUIRED
FAA METHOD
(100-YEAR)
LOCATION: Kingdom Hall of Jehovahs Witness
PROJECT NO: 242-01
COMPUTATIONS BY: ppk
DATE: 4/3/05
Equations: A trib. To pond = 1.52
QD = CA Cioa = 0.87
Vi = T*CiA = T*QD Developed C*A = 1.3
V. =K*Qro*T QPo = 0.76
S=Vi -V. K= 1
Rainfall intensity from City of Fort Collins IDF Curve
acre
acre
cfs (0.5 cfs/acre)
(from fig 2.1)
Storm
Duration, T
(min)
Rainfall
Intensity, i
(in/hr)
QD
(cfs)
Vol. In
Vi
(ft)
Vol. Out
Va
(ft3)
Storage
S
(ft3)
Storage
S
(ac-ft)
5
9.95
13.2
3947
228
3719
0.09
10
7.72
10.2
6125
456
5669
0.13
20
5.60
7.4
8887
912
7975
0.18
30
4.52
6.0
10759
1368
9391
0.22
40
3.74
4.9
11870
1824
10046
0.23
50
3.23
4.3
12814
2280
10534
0.24
60
2.86
3.8
13615
2736
10879
0.25
70
2.62
3.5
14552
3192
11360
0.26
80
2.38
3.1
15107
3648
11459
0.26
90
2.22
2.9
15853
4104
11749
0.27
100
2.05
2.7
16266
4560
11706
0.27
140
1.93
2.6
16845
5016
11829
0.27
120
1.80
2.4
17138
5472
11666
0.27
130
1.60
2.1
16504
5928
10576
0.24
140
1.40
1.9
15551
6384
9167
0.21
150
1.20
1.6
14282
6840
7442
0.17
160
1.15
1.5
14599
7296
7303
0.17
170
1.10
1.5
14837
7752
7085
0.16
180
1.05
1.4
14996
8208
6788
0.16
Required Storage Volume: 11829 ft3
0.272 acre-ft
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APPENDIX C
DETENTION CALCULATIONS
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M M M= r= M M = = = M r= M= i i r
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
RATIONAL METHOD PEAK RUNOFF
(100-YEAR)
LOCATION: Kingdom Hall of Jehovahs Witness
PROJECT NO: 242-01
COMPUTATIONS BY: ppk
DATE: 4/3/05
DIRECT RUNOFF
CARRYOVER
TOTAL
Inlet Capacity
REMARKS
Design
Point
SUBBASIN
DESIGNATION
A
(ac)
C1w
TOgw
(min)
i
(in/hr)
Q1w
(cfs)
from
Design
Point
Q1w
(cfs)
Qiw Total
(cfs)
(cfs)
1
1
1.52
0.87
7.0
8.80
11.6
11.6
to detention pond
2
2
1.07
0.25
9.6
7.85
2.1
1 2.1
Undeveloped
Q=CiA
Q = peak discharge (cfs)
C = runoff coefficient
i = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
Flow.xls Q100
r= r r r r rr r r rs r r, r r r r
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
RATIONAL METHOD PEAK RUNOFF
(10-YEAR)
LOCATION: Kingdom Hall of Jehovahs Witness
PROJECT NO: 242-01
COMPUTATIONS BY: ppk
DATE: 4/3/05
DIRECT RUNOFF
CARRY OVER
TOTAL
Inlet Capacity
REMARKS
Design
Point
SUBBASIN
DESIGNATION
A
(ac)
CIO
TOC"
(min)
i
(in/hr)
Q10
(cfs)
from
Design
Point
Qio
(cfs)
Qio Total
(cfs)
(cfs)
1
1
1-.52
0.69
9.1
3.91
4.1
4.1
2
2
1.07
0.20
10.0
3.78
0.8
0.8
Q=CiA
Q = peak discharge (cfs)
C = runoff coefficient
i = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
Flow.xls Q10
s M M M r r it r M r" r i M s MIft m r
TIME OF CONCENTRATION
100-YEAR
LOCATION:
Kingdom Hall of Jehovahs Witness
PROJECT NO:
242-01
COMPUTATIONS BY:
SB
DATE:
4/3/05
SUB -BASIN DATA
INITIAL / OVERLAND TIME
W
TRAVEL TIME / CHANNEL FLOW
00
t, CHECK
(URBANIZED BASIN)
FINAL
t,
REMARKS
DESIGN
POINT
SUBBASIN
DESIGNATION
(1)
Area
(ac)
(2)
C*Cr
(Cr= 1.25)
(3)
Length
(ft)
(4)
Slope
(%)
(5)
t;
(min)
(6)
Length
(ft)
(7)
Slope
(%)
(8)
V
(ft/s)
(9)
4
(min)
(10)
t,
(min)
(11)
Total L
(ft)
(12)
t (L / 180)+10
(min)
(13)
(min)
(14)
1
1
1.52
0.87
45
1.2
2.74
300
0.6
1.2
4.30
7.0
345
11.9
7.0
2
2
1.07
0.25
20
I.0
7.11
290
1.7
2.0
2.47
9.6
310
11.7
9.6
EQUATIONS:
tc=ti+t
t;=[1.87(1.1-C*Cr)05]/S113
t,=L/V where V=C,,*Sw5
final t, = minimum of t; + 4 and urbanized basin check
(C,, from Table RO-2)
M r m r M m r r M " M " M m m m in r
TIME OF CONCENTRATION
10-YEAR
LOCATION:
Kingdom Hall of Jehovahs Witness
PROJECT NO:
242-01
COMPUTATIONS BY:
ppk
DATE:
4/3/05
SUB -BASIN DATA
INITIAL / OVERLAND TIME
(t,)
TRAVEL TIME / CHANNEL FLOW
(t,)
t, CHECK
(URBANIZED BASIN)
FINAL
t,
REMARKS
DESIGN
POINT
SUBBASIN
DESIGNATION
(1)
Area
(ac)
(2)
C*Cf
(Cf= 1.0)
(3)
Length
(ft)
(4)
Slope
(%)
(5)
t;
(min)
(6)
Length
(ft)
(7)
Slope
(%)
(8)
V
(ft/s)
(9)
t,
(min)
(10)
t,
(min)
(11)
Total L
(ft)
(12)
t,= (L / 180)+10
(min)
(13)
(min)
(14)
l
1
1.52
0.69
45
1.2
4.79
300
0.6
1.2
4.30
9.1
345
11.9
9.1
2
2
1.07
0.20
20
1.0
7.53
290
1.7
2.0
2.47
10.0
310
11.7
10.0
EQUATIONS:
tc=t;+t,
t;=[1.87(L1-C*Cf)L0.5]/S113
t,=L/V whereV=C,*Sw5
final t, = minimum of t; + t, and urbanized basin check
(C from Table RO-2)
r,
M NoMW DesPW. M M � M r M a IMIM WSW M M I r
700 Automation Drive, Unit I
Windsor, CO 80550
RUNOFF COEFFICIENTS & % IMPERVIOUS
LOCATION: Kingdom Hall of Jehovahs Witness
PROJECT NO: 242-01
COMPUTATIONS BY: ppk
DATE: 4/3/05
Recommended % Impervious from Urban Storm Drainage Criteria Manual
Streets, parking lots (asphalt):
Sidewalks (concrete):
Roofs:
Lawns (Average <2%, heavy soil):
Runoff
%.
coefficient
Impervious
C
0.95
100%
0.95
96%
0.95
90%
0.20
0%
SUBBASIN
DESIGNATION
TOTAL
AREA
(ac.)
TOTAL
,AREA
(sq.ft)
ROOF
AREA
(sq.ft)
PAVED
AREA
(sq.ft)
SIDEWALK
AREA
(sq.ft)
LANDSCAPE
AREA
(sq.ft)
%
Impervious
RUNOFF
COEFF.
(C)
1
1.52
66,014
6,270
35,910
1,340
22,494
65%
0.69
2
1.07
46,420
0
0
0
46,420
0%
0.20
Flow.xls Cval
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' APPENDIX B
HYDROLOGIC COMPUTATIONS
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APPENDIX A
VICINITY MAP
A
Conveyance systems have been sized and will convey the required flows to the pond as
required. The storm system on site will be a privately owned and maintained.
If, at the time of construction, groundwater is encountered, a Colorado Department of
Health Construction Dewatering Permit would be required.
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.
3. McClellands Creek Master Drainage Plan Update by ICON Engineering, Inc.
dated November 30, 2000.
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4.3 Drainage Summary
. 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 and detention outlet pipe) will be
maintained by the owners of the site.
5. EROSION CONTROL
5.1 General Concept
This site lies within the Moderate Rainfall and Wind Erodibility Zone per the City of Fort
Collins Zone Maps. The potential exists for silt movement from the site and into the
existing storm system during construction. Potential also exists for tracking of mud onto
existing streets which could then wash into existing storm systems.
Silt fence will be provided around the perimeter of the site, a construction entrance will
be provided at the exit from the site and wattles will be provided around the outlet pipe
and in all swales. The incorporation of these best management practices will reduce the
amount_ of sediment leaving the site during construction. The detailed design and
required calculations for the erosion control will be completed with the final design for
this project.
't 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 Erosion Control Reference Manual for Construction Sites and the
Storm Drainage Design Criteria Manual.
6.2 Drainage Concept
The proposed drainage concepts presented in this report and on the construction plans
adequately provide for the collection and conveyance of runoff to the detention area.
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3.4 Hydraulic Criteria
All hydraulic calculations will be prepared with the final design for this site.
4. DRAINAGE FACILITY DESIGN
4.1 General Concept
The runoff from this site will be collected in the on site curb and be conveyed to the
proposed detention area in the southeast corner of the site. This pond will attenuate the
runoff to 0.5 cfs per acre and will discharge the water to the proposed storm pipe system
along the east boundary of the site. This pond will also provided extended detention for
water quality.
No off site flows enter the site from adjacent properties. Flow from offsite is intercepted
by Timberline Road on the west, an existing irrigation ditch on the north and Kechter
' Road on the south. Only small portions of the landscape areas on the south, north and
east will be released from this site undetained.
4.2 Specific Flow Routing
jThe site has been divided into two basins and a summary of the drainage patterns within
each basin is provided in the following paragraphs.
Basin 1 contains the majority of the proposed development including all of the proposed
building, the parking lot, a majority of the drives and the detention basin. The runoff
from this basin is conveyed via concrete pans and curb & gutter to a curb opening in the
southeast comer of the parking lot. The runoff then enters the detention pond and is
detained before being released to the proposed storm pipe -system on the east.
Basin 2 contains the north portion of the site which is not proposed to be developed at
this time. The runoff from this basin will be allowed to flow to the northeast corner of
the site as it currently does. Detention and water quality extended detention will be
required for this site when development is proposed.
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convey the runoff from the proposed development to a detention pond and then north in a
storm pipe and proposed swale to the existing concrete channel in Stetson Creek Second
Filing. This pan will then convey the water east to the McClellands Basin Drainageway.
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), 1984, developed by the Denver
Regional Council of Governments, has been used.
3.2 Development Criteria Reference and Constraints
The runoff from this site has been routed to the proposed detention pond on site.
Detention and water quality facilities will be provided for the proposed development on
site and the undeveloped portion of the site will not be detained at this time. The pond
will release to the northeast corner of the overall site and be conveyed in a proposed
Swale to the existing concrete channel along the south side of the Stetson Creek Second
Filing.
3.3 Hydrologic Criteria
Runoff computations were prepared for the 5 and 10-year minor and 100-year major
' storm frequency utilizing the rational method.
All hydrologic calculations associated with the basins are included in Appendix B of this
report. Standard Form 8 (SF-8) provides time of concentration calculations.. for --all sub -
basins. Standard Form 9 (SF-9) provides a summary of the design flows for all Sub -
basins and Design Points associated with this site.
Detention volume was calculated based on a release rate of 0.5 cfs per acre. The FAA
method for detention pond sizing was utilized to determine the required volume. Water
quality volume was calculated using the method recommended in the "Urban Storm
Drainage Criteria Manual'.
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1. GENERAL LOCATION AND DESCRIPTION
1.1 Location
This site is located on the northeast corner of the intersection of Timberline Road and
Kechter Road in Fort Collins. This project is located in the Southwest Quarter of Section
5, Township 6 North, Range 68 West of the Sixth Principal Meridian, in the City of Fort
Collins, Larimer County, Colorado. See the location map in Appendix A.
The project is bounded on the north and east by existing estate lot residential properties,
on the west by existing Timberline Road and on the south by Kechter Road.
1.2 Description of Property
The entire project consists of approximately 2.75 acres of land. A house and several
outbuildings exist on the site and the site slopes to the southeast and the northeast at
slopes ranging from 1 to 1.5 percent. An irrigation ditch exists on the site which divides
the runoff into two directions.
With this project, the site will be divided into two lots and only the south lot will be
developed at this time. This project will include demolishing the existing structures on
site and construction of a church building and a residence with associated parking and
drives. Detention will be provided in the southeast comer of the site. The pond will
outlet to the northeast comer of the overall site.
2. DRAINAGE BASINS AND SUB -BASINS
2.1 Major Basin Description
The proposed development lies within the McClellands-Mail Creek Drainage Basin. It is
proposed that the detention area on site release at 0.5 cfs per acre.
2.2 Sub -basin Description
The portion of the site that is proposed to be developed at this time currently drains
southeast and into the existing roadside ditch along Kechter Road. The runoff then flows
east along Kechter to Mail Creek. With the proposed development, it is proposed to
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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..........................................................................................I
2.2 Sub -Basin Description.............................................................................................1
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....................................................................................................3
4.
DRAINAGE FACILITY DESIGN
4.1 General Concept .......................................................................................................3
4.2 Specific Flow Routing.............................................................................................3
.
5.
4.3 Drainage Summary ...................................................................................................3
EROSION CONTROL
5.1 General Concept......................................................................................................4
5.2 Specific Details........................................................................................................4
6.
CONCLUSIONS
6.1 Compliance with Standards....................................................................................4
6.2 Drainage Concept.....................................................................................................4
7.
REFERENCES ................................
W APPENDICES
A Vicinity Map .
B Hydrologic Computations
C Detention Pond Sizing
D Figures and Tables
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North Star
aft=, design, inc.
April 5, 2005
Basil Hamdan
City of Fort Collins Stormwater
700 Wood Street
Fort Collins, CO 80522-0580
RE: Preliminary Drainage & Erosion Control Study for Kingdom Hall Addition
Dear Basil,
I am pleased to submit for your review and approval, this Preliminary Drainage and Erosion
Control Study for Kingdom Hall Addition church facility. I hereby certify that this report for the
drainage design was prepared in accordance with 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.
ii
700 Automation Drive, Unit I Windsor, Colorado 80550
970-686-6939 Phone • 970-686-1 188 Fax
PRELIMINARY DRAINAGE AND EROSION
CONTROL STUDY
KINGDOM HALL ADDITION
Prepared for:
Poudre Valley Congregation
KC Johnson
4985 Hogan Drive
Fort Collins, CO 80525
Prepared by:
North Star Design
700 Automation Drive, Unit I
Windsor, Colorado 80550
(970)686-6939
April 5, 2005
Job Number 242-01