HomeMy WebLinkAboutDrainage Reports - 01/12/2018IKA
December 2017
City of Fort Collins Utilities Department
222 Laporte Ave
Fort Collins, Co 80522
Our Savior's Lutheran Church Building Addition
Dear Sir or Madam:
City of Fort OlCoollilsAppreu4�+ plans
Approved by:Date: _..._
The proposed project is located on the north-east corner of the intersection of S Lemay Ave and
Kirkwood Dr. and will be consist of the construction of additions to the existing Our Savior's
Lutheran Church building.
Because this is an existing building the proposed additions to the building will not have a major
effect on the existing drainage patterns of the site. The additions will however cause an increase
in the amount of runoff produced by the site. A rain garden and detention pond have been
proposed to capture and treat the increase in stormwater runoff. The areas used to determine
the increase in stormwater runoff were calculated by subtracting the area of pavement that will
be removed from the area of pavement and roof area that are being proposed.
Olsson has completed drainage calculations per City of Fort Collins Stormwater Criteria using
the Modified FAA method to determine the required storage volume for the increased runoff.
The increased imperviousness area was determined to be 0.19 AC with a percent
imperviousness value of 90%. The required water quality volume was calculated using Urban
Drainage and Flood Control District's Stormwater Best Management Practice Design Workbook
V3.06 Rain Garden Design Procedure Form. The required storage volume from the Modified
FAA method was calculated using the City of Fort Collins Modified FAA Worksheet. The
detention pond release rate was determined using the rational method to calculate runoff
generated in the historic 2-year rainfall event. See the enclosed calculations for more
information.
Based on the results from the City of Fort Collins Modified FAA Worksheet, the required
detention pond storage volume for the increased runoff was determined to be 1,793 CF. Based
on the results from the Stormwater Best Management Practice Design Workbook V3.06 Rain
Garden Design Procedure Form, the required Water Quality Capture Volume was determined to
be 221.5 CF.
In order to improve drainage conditions on the west lawn of the site the required water quality of
the site will be captured in a rain garden. The rain garden will be installed per city of Fort Collins
detail D-53. The addition of an 8" PVC pipe that will be attached to the roof drains along the
west side of the building will also be added. Both the rain garden and the 8" PVC roof drain pipe
will outlet in the proposed detention pond to the north. The outlet for the pond will be a 4" PVC
pipe in a headwall with a restrictor plate to restrict the flow to the allowable peak outflow rate
determined using the rational method (0.08 cfs).
If you have any questions or need additional information, please feel free to contact me @ 970-
635-3714.
Sincerely,
Olsson Associates
Mike Maurer, PE
Enclosures
• Vicinity Map
• Release Rate Calculation
• Percent Imperviousness Calculation
• Required Rain Garden Volume Calculation
• Required Storage Volume Calculation
• Restrictor Plate Sizing
• Detention Pond Drain Time Calculation
• Grading Plan
1880 Fall River Drive, Suite 200 TEL 970.461.7733
Loveland, CO 80538 www.olssonassociates.com
m
Vicinity Map
I
■ Kirkwood Dr
5285 McWhinne Boulevard
Our Savior's Lutheran OLSSON , 8ude 160 Y
Church Loveland, CO 80538
ASSOCIATES TEL 970 431.7733
•
C = 0.15 (2% impervious)
i = 2.85 in/hr (2-year historic runoff, 5 minute Tc)
A = 0.19 acres (area of improvements)
Q = CiA = A 15*2.85*0.19) = 0.08 cfs
r 1880 Fall River Drive
Release Rate Our Saviors Lutheran
I ^1 Suite 200
Calculation Church v N ® Loveland, CO 80538
ASSOCIATES TEL 970.461.7733
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Design Procedure Form: Rain Garden (RG) II
UD-BMP (Version 3.06. November 2016) Sheet 1 of 2
Designer: Erica Morton
Company:
Olsson Assocaites
Date:
October 4, 2017
Project:
Our Saviors Lutheran Church (017-1434)
Location:
Fort Collins, CO
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, 1.
I„ =
90.0
%
(100 % d all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = I,1100)
=
0.900
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time
W CCV =
0.32
watershed inches
(WQCV=0.8-(0.91•0-1.19-I?+•0.78-I)
D) Contributing Watershed Area (including rain garden area)
Area =
8,276
sq It
E) Water Quality Capture Volume (WQCV) Design Volume
Vwocv =
cu It
Vol = (WQCV / 12) - Area
F) For Watersheds Outside of the Denver Region, Depth of
de =
0.43
in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region.
VWOCVOTNER =
221.5
cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume
Vwav USER =
cu it
(Only K a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)
Dw=v=
3.0
in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical)
Z =
10.00
ft/ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area
AMA, =
149
sq it
D) Actual Flat Surface Area
A, =
625
sq It
E) Area st Design Depth (Top Surface Area)
ATv =
1213
sq it
F) Rain Garden Total Volume
VT=
230
ou it
(VT= ((AT.' Ak ) / 2) " Depth)
3. Growing Media
Choose! One
® 18' Rain Garden Growing Medle
O other(Eplain):
4. Underdrain System
Choose One
Ir
# YES
A) Are underdrains provided?
Q NO
B) Underdmin system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage
y=
0.5
ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours
V0112=
222
cu ft
iii) Orifice Diameter, 3/8" Minimum
Do =
112
in
Rain Garden Calcs.xlsm. RG
10/412017, 2:56 PM
Design Procedure Form: Rain Garden (RG)
Sheet 2 of 2
Designer: Erica Morton
Company: Olsson Assocaites
Date: October 4, 2017
Project: Our Savloh Lutheran Church (017.1434)
Location: Fort Collins, CO
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
Choose One -
Q YES
A) Is an impermeable liner provided due to proximity
NO
of structures or groundwater contamination?
6. Inlet / Outlet Control
r Choose One
I Q Sheet Flow- No Energy Dissipation Required
A) Inlet Control
I Q Concentrated Flow- Energy Dissipation Provided
Choose One
7. Vegetation
(9 Seed (Plan for frequent weed control)
p Plantings
Q Sand Grown or Other High Infiltration Sod
8. Irrigation
rChoose One
11$
A) Will the rain garden be irrigated?
L NO J
Notes.
Rain Garden Calcs.xlsm, RG 10/4/2017, 2:56 PM
100 Year
This is to convert % imp- to a C value
1 00-ear
must insert % imp. and C pervious).
Required detention
ft3
acre-ft.
'C' value
0.731
1720.9
0.040
'C'* 1.25
0.9125
Area 1
0. 191
acres
Modified
Modified
Release Rati
0.08
M. FATER
D. JUDISH
C. LI
5/95
Nov-97
Nov-98
DETENTION POND SIZING
TIME
TIME
INTENSITY
Q 100
Runoff
Release
Required
Required
cum
100 year
Volume
Cum total
Detention
Detention
mins
secs
in/hr)
(cfs)
(ft^3
ft^3
ft^3
ac-ft
0
0
0.00
0.00
0.00
0
0.00
0.00
5
300
9.95
1.73
517.52
24
493.52
0.01
10
600
7.72
1.34
803.07
48
755.07
0.02
15
900
6.52
1.13
1017.36
72
945.36
0.02
20
1200
5.60
0.97
1165.08
96
1069.08
0.02
25
1500
4.98
0.86
1295.11
120
1175.11
0.03
30
1800
4.52
0.78
1410.58
144
1266.58
0.03
35
2100
4.08
0.71
1485.48
168
1317.48
0.03
40
2400
3.74
0.65
1556.21
192
1364.21
0.03
45
2700
3.46
0.60
1619.67
216
1403.67
0.03
50
3000
3.23
0.56
1680.00
240
1440.00
0.03
55
3300
3.03
0.53
1733.58
264
1469.58
0.03
60
3600
2.86
0.50
1785.07
288
1497.07
0.03
65
3900
2.72
0.47
1839.16
312
1527.16
0.04
70
4200
2.59
0.45
1885.97
336
1549.97
0.04
75
4500
2.48
0.43
1934.87
360
1574.87
0.04
80
4800
2.38
0.41
1980.64
384
1596.64
0.04
85
5100
2.29
0.40
2024.85
408
1616.85
0.04
90
5400
2.21
0.38
2069.06
432
1637.06
0.04
95
5700
2.13
0.37
2104.95
456
1648.95
0.04
100
6000
2.06
0.36
2142.92
480
1662.92
0.04
105
6300
2.00
0.35
2184.53
504
1680.53
0.04
110
6600
1.94
0.34
2219.89
528
1691.89
0.04
115
6900
1.89
0.33
2260.98
552
1708.98
0.04
120
7200
1.84
0.32
2296.87
576
1720.87
0.04
Page 1
RESTRICTOR PLATE SIZING FOR CIRCULAR VERTICAL ORIFICES
Project: Our Savior's Luteran Church
Basin ID:
DIa—
T
0 0 o 0
0 0 / \ 0 0
Sizing the Restrictor Plate for Circular Vertical Orifiws or Pipes (Inputl
Water Surface Elevation at Design Depth
Elev_ WS =
PipeNertical Orifice Entrance Invert Elevation
Elev: Invert =
Required Peak Flow through Orifice at Design Depth
O =
PipeNertical Onfice Diameter (inches)
Dia =
Orifice Coefficient
Ca =
Full -flow Capacity (Calculated)
Full -flaw area
Half Central Angle in Radians
Full -flow capacity
Calculation of Orifice Flow Condition
Half Central Angle (0<Theta<3.1416)
Flow area
Top width of Orifice (inches)
Height from Invert of Orifice to Bottom of Plate (feet)
Elevation of Bottom of Plate
Resultant Peak Flow Through Orifice at Design Depth
Width of Equivalent Rectangular Vertical Orifice
pi Vertical
Onfice
42 Vertical
Orifice
4,979,00
4,97700
0.08
4.0
0.65
feet
feet
cfs
inches
At = 0.09 eq It
Theta = 3.14 red
Of = 0.6 cfs
Percent of Design Flow -1 775%
Theta =
0.85
red
k =
0.01
aq 0
Te=
299
Inches
Y. =
0.06
feet
Elev Plate Bottom Edge =
4,977.06
feet
Oe =
0.08
ds
Equivalent Width =
0.77
feet
UD-Detention v2.34.ais. Restrictor Plate
iF7lN111 Mi-Mlu1
Stormwater Detention and Infiltration Design Data Sheet
OSLC Detention Pond
Stormwater Facility Name:
Facility Location & Jurisdiction: Fort Collins, CO
User (Input) Watershed Characteristics
Watershed Slope =
0.010
ft/ft
Watershed Length -to -Width Ratio =
2.00
L:W
Watershed Area =
0.19
acre
Watershed Imperviousness=
90.0°%
pert
Percentage Hydrologic Soil Group A =
0.0%
pert
Percentage Hydrologic Soil Group B =
0.0%
pert
Percentage Hydrologic Soil Groups C/D =1
100.0%
pert
User Input: Detention Basin Characteristics
WQCV Design Drain Time = 12.00 hours
After completing and printing this worksheet to a pdf, go to:
https:Ilmaperture.digitaidatase"pces.com/gvh/?viewer=cswdif.
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Design Storm Return Period
Two -Hour Rainfall Depth
Calculated Runoff Volume
OPTIONAL Override Runoff Volume
Inflow Hydrograph Volume
Time to Drain 97% of Inflow Volume
Time to Drain 99% of Inflow Volume
Maximum Ponding Depth
Maximum Forded Area
Maximum Volume Stored
Rnutpd Hvdrnpranh Rpcuit<
User Defined
Stage Ift]
User Defined
Area [ft^2]
User Defined
Stage lft�
User Defined
Discharge [cfs]
0.00
20.99
0.00
0.08
0.10
100.90
0.10
0.08
0.20
288.44
0.20
0.08
0.30
571.15
0.30
0.08
0.40
691.89
0.40
1 0.08
0.50
837.53
0.50
0.08
0.60
1002.00
0.60
0.08
0.70
1153.86
0.70
0.08
0.80
1301.74
0.80
0.08
0.90
1373.59
0.90
0.08
1.00
1447.65
1.00
0.08
1.10
1528.25
1 1.10
0.08
1.20
1615.41
1.20
0.08
1.30
1713.88
1.30
0.08
1.40
1795.53
1.40
0.08
1.50
1878.28
1.50
0.08
1.60
1962.11
1.60
0.08
1.70
2047.03
1.70
0.08
1.80
2155,64
1.80
0.08
1.90
2250.65
1.90
0.08
2.00
2349.67
2.00
0.08
2.10
2452.72
2.10
0.08
2.20
2559.79
2.20
0.08
WQCV
2 Year
5 Year
10 Year
25 Year
50 Year
100 Year
0.53
0.98
1.36
1.71
2.31
2.91
3.67
0.005
0.014
0.020
0.026
0.036
0.046
0.059
0.01
0.04
0.05
0.005
0.009
0.019
0.035
0,035
0.046
0.052
1
2
3
5
5
7
8
1
2
3
5
5
1 7
8 ji
0.14
0.35
0.75
1.17
1.17
1.42
1.57
0.004
0.014
0.028
0.036
0.036
0.042
0.044
0.000
0.002
0,011
0.024
0.024
0.034
0.040
n
cre-ft
cre-ft
cre-ft
lours
lours
t
cres
cre-ft
SDI_Design_Data_FC_Rainfall.xlsm, Design Data 12/12/2017, 10:13 AM
1.2
1
0.8
3 0.6
s
0.4
0.2
0
0.2
_8
1.6
1.4
g 0.8
0.6
0.4
0.2
0
0.1
Stormwater Detention and Infiltration Design Data Sheet
—100YR
— — 100YR O OUT
—50YR IN
50YR OUT
— 25YR IN
— — -- 25YR OUT
If
—
_—
—10YR IN
— — — 10YR OUT
—SYR IN
--
I
--
-
-
......SYR OUT
—2YR IN
— — — 2YR OUT
--
—
-
-
—WQCV IN
•••••• WQCV OUT
i
1
TIME [hrj
10
1 10 100
DRAIN TIME [hr]
SDI_Design_Data_FC_Rainfall.xlsm, Design Data 12/12/2017, 10:13 AM
I'
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I/VOLUME
CERAMICS _
�- Z= CANL NC ITIE SCALE IN FEET
PROPOSED B' UTILITY
__ EASEMENT BY SEPARATE
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L ��
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NOTES
1. ALL DIMENSIONS ARE MEASURED FROM FLOWLINE OR BUILDING
FACE UNLISS NOTED OMERMSE.
2. ME EXISTING UTILTY LOCATIONS SHOWN ON THE PLANS ME
APPROXIMATE AND MAY NOT INCLUDE ALL ONES PRESENT. ME
CONTRACTOR SHALL BE RESPONSIBLE FOR CAWNG ME UTILITY
NOTFlCARON CENTER AT 811 AND COORDINATING FIELD
LOCATIONS W EXISTING UNDERGROUND UTILITIES PRIOR TO
BEGINNING GRATING AND UTILITY WORK.
1 CONTOURS SHOWN AT UT INTERVALS.
C POND RELEASE RATE IS 0.17CFS. SEE DISCHARGE RESMICTOR
PLATE DETAIL.
5. SEE DETAIL SHEET C8.1 FOR NOISE INFORMATION ON
INSTALLATION OF RAIN GARDEN MD UNDERMAIN PIPE.
INSET 1
SCALE 1:20
° "
LEGEND
W
EXISTING
PROPOSED
Z�
PROPERTY LINE
OF AMMIMMI m ma
- - -
FLOV INE
-
- - -- -
BACK OF CURB
U
EASEMENT
- - - - - - - - - - - - -
N
-_ - --.-
SETBACK LINE
- - - - -
USAGE BREAK
- -
. ^ I/I
- -5>50 - - -
GCNrouRs
57Wv
.%EIB
- --5]4 ---
MINOR S
MINWCER
w --
LINE
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m
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AR
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TOP BERM
TOB
ixlamcuBY
POND
BED
BOP
RELEASED BYOLSSOeEEx
FLOOR
FINISHED FLOOR ELEVATION FEE
By RUGHRATCRY AGENCIES AND
s.
uH �is
SUBIECTTTTOCHNNC
DOCUMENT IS HIGH TO BE
SOFT FBI TROUE CHAIML
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TGP.4Bm.4G -
TOP 491
OFTHECONTRIkCTORTORRELD
IQ
VERIFY THE LEGATION OF
PER: 49T9. SDy -1 --.. ...
TCP:48]B.50TW:4979.W
MEG:4%8.8T
INSET 2
SCALE 1:20
fist TIE
TO EXISTING
4' PVC SHOT ELBOW
4' OVERFLOW GRATE
WSEL 497B 80
C CLEANOUT
,_ AEG-.o.,ll�u•4-.,,
4' OUTUJ PIPE INVERT 497818
FINISHED GRADE 4978.55
BIORETENTION SAND MEDIA DEPTH 49]].55
PEA GRAVEL DEPTH 4977.05
COOT NO. 4 AGGREGATE DEPTH 4970.38
4• PVC 90' ELBOW
C PVC 9w [[LBOW
4' PERFORATED UNDER RAIN PIPE
INVERT 497B.55
^YEG49m.99
RAIN GARDEN DETAIL
NOT 10 SCALE
MEG AT WE I I
/ .� I Di ta.
4' i0N0 PIPE as
INV. Nv: 49 avn.00 DISCHARGE
f f / / ✓ RESTRICTOR PLATE
IF / /'/ /� 'IL... NOT TO SCALE
`0E2,4B]7795
PROPOSED
GROUND
ITx3' RAT BAR HOLDING FRAME
STAINLESS STEEL. ANCHOR
BOLTS OR INTERMITTANT
WELDS ON TOP AND SIDES.
1w LGG'
Sow -]
C POND OUTLET PIPE
INN 49]].W
0.3' M51
0.S' T
5. PROPOSED
DETENTION POND OUTLET STRUCTURE DETAIL
NOT TO SCALE
POND PARAMETERS
RAIN GARDEN
REQUIRED VOLUME
22,5 CUBIC FEET
PROVIDED VOLUME
220 CUBIC FEET
EOTTOMOFRAINGAROEN
49)8.55
TWOFRNNGARDEN
49I8,W
DETENTION POND
REQUIREOVOLUME
12N CUBIC FEET
10DYR PROVIDED VOLUME
1%S CUBIC FEET
BOTTOM OF POND
49]].Op
100'IR OUSEL
18]B.B11
TW OF FCNO
IBT8.50
RELEASE RATE
0.%CF8
UU
Z
U2
H
3�
W
Z
aLL
o
g
wo
(L
PROJECT DATUM: NAVD88
U
Z
F
O
W
UI
BENCHMARK M-92 SOUTHWEST CORNER OF DARTMOUTH TRAIL
=
Z
AND LEMAY AVE, UH A DIVERSION WALL AT ME ARTHUR DITCH.
J
1
Q
ELEVATION: 4981.80
0)
K
BENCHMARK 19-92 SOUTHWEST CORNER OF EAST DRAKE RD.
O
d
-L
CJ
AND LEMAT AVE. ON TOP OF A SANITARY SEWER PUMP STATION.
ELEVATION: 4978.40
%
LL
z
PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL
N
V
DATUM. SURROUNDING DEVELOPMENTS HAVE USED NGW29
UNADJUSTED FOR THEIR VERTICAL DATUMS
Q•
Q
=
IF NGVD29 UNADJUSTED DATUM IS REWIRED FOR ANY PURPOSE,
0
~
ME FOLLOWING EQUATION SHOULD BE USED:
MM29 UNADJUSTED = NAVD88 - 3.18
PROJECT SITE BENCHMARK -
UPS DERIVED BENCHMARK BEING A SET /5 PERM (POINT /I11)
SET AT ME HEST CENTER CORNER OF MAIN BUILDING AND
NORM OF WEST PATIO AREA ELEV.-4947.15' (NAVD88)
MCI
W
MY
Wlh
W
BASIS OF BEARING:
wMLMIo:
B^-m
WwWwlw..
c cRD an
P02)
BEARINGS ARE BASED ON A SET CHISELED '4)
Ua9m1
MC1Y WHICH A SET CHIE PO4) BEARS
EMS
DISTANCE OF 180.69 FEET. ALL BEARINGS SHOWN
OF 18 49 FEET.
SHEET
HERM ARE, E
HERON ARE REIATINE HERETO.