HomeMy WebLinkAboutDrainage Reports - 04/19/1990T3DINC
Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
303/226-4955
April 12, 1990
Glen Schlueter
City of Fort Collins
Stormwater Utility Dept.
P.O. Box 580
Fort Collins, CO. 80522
RE: SILVERPLUME ESTATES THIRD FILING
REVISED FINAL DRAINAGE REPORT
Dear Glen:
This letter report is to outline the approach taken to design the
drainage facilitie for the forementioned project. The develop-
ment consists o 34 Ingle family residential lots and two deten-
tion areas situa ed on 7.53 acres. The site is located northeast
of the intersection of Swallow Road and Dunbar Avenue. The
project site is bounded on the south by Swallow Road, on the west
by Dunbar Avenue, on the north by the Silverplume Condominium
development and on the east by the Peace with Christ Lutheran
Church parcel. The site is bisected east and west by Silverplume
Drive. The Second Filing of Silverplume Estates is situated in
the middle of this filing along Silverplume Drive.
Currently the site is covered by field grasses with the southwes-
tern third of the site draining toward the intersection of Swal-
low Road and Dunbar Avenue. A small portion of the site west of
Silverplume Drive drains north into the Silverplume Condominium
development. The portion of the site east of Silverplume Drive
drains to the east. The entire site sets on a slight ridgeline,
therefore no offsite flows are anticipated.
In the original Silverplume P.U.D. development plan, the proposed
site area was planned for multi -family development. Detention
facilities were sized accordingly. The proposed single family
development will be less intense, therefore the detention volumes
have been recalculated. Overall drainage patterns will remain
the same except in the area east of Silverplume Drive. In this
area, flows from Basins E, F, G. and H will be directed south to
two interconnecting ponds in the southeast corner of the site.
These two ponds are connected by a 15" diameter storm drain pipe,
thus act as one large detention pond. This substantially reduces
the flows entering the Silverplume townhouse area to the north.
\D
Other Offices: Vail, Colorado 303/476.6340 • Colorado Springs, Colorado (719) 598-4107
The detention area in the southwest corner of the site has been
sized to detain flows from Basins A and B. Flows are diverted
into this pond through on grade sidewalk culverts in Dunbar
Avenue and Swallow Road and a sump sidewalk culvert in Telluride
Court.
Flows from Basins C and D flow offsite and are detained in
facilities in the Silverplume townhouse area. Basins C and D
comprise 2.15 acres. This compares to 2.6 acres draining north
in the original grading plan for the Silverplume P.U.D. It
should be pointed out that the original plan (dated 7-10-79 -
copy attached) called for six onsite ponds designated D. E, F, G,
H, and I totaling 102,080 cu. ft. of detention volume. The
original plan was revised in 1980 and 1982 to eliminate ponds D
and H. The revised ponds were relocated and redesignated to
ponds D. F, F-11 G, G-1, and I. These revised ponds totaled
166,420 cu. ft. of detention volume. The increase in detention
volume along with the rerouting of flow mentioned earlier jus-
tifies allowing Basins C and D to drain offsite without further
analysis.
Flows from Basins E, F, G. and H are diverted into the two con-�
necting detention ponds in the southeast corner of e site
through sump sidewalk culverts in Teller and Silverton Court and
a on grade sidewalk culvert on Swallow Road.
A small area (Basin I) in the northeast corner of the site drains
offsite onto the Peace with Christ Lutheran Church parcel. This
basin area consists of merely the backyards of two lots and is
graded in this manner to better match the adjacent area. Flows
from this area are negligible when compared to the historic
runoff pattern. Historically, runoff from approximately 3.7
acres of land east of Silverplume Drive would flow on to the
Church's parcel as compared to the proposed 0.27 acres of land
area from Basin I. This comparison results in 4.35 cfs for his-
toric runoff and 1.20 cfs for the developed runoff assuming the
100 year storm frequency.
The attached calculations reflect the approach outlined above.
The City of Fort Collins standard detention and drainage con-
veyance criteria should be maintained with the approach outlined
within this report.
Should you have any questions, please feel free to contact us.
Sincerely,
RBD, Inc.
',
Stan A. Myers P E.
cc: 367-002
SVLRPL#3.DGE
POND CALCULATIONS
MASS DIAGRAM METHOD
+or -
DETENTION VOLUMES
PROJECT: SILVERF'LUME - THIRD FILING
COMMENTS:100 YEAR DETENTION VOLUMES
SOUTHWEST DET. POND
BASINS A °- B
MAXIMUM ALLOWABLE RELEASE (CFS)
RATIONAL EQUATION: 0 = CIA
✓
AC
C+C+=
0.625
A(area)
= 4.08
TIME OF CONCENTRATION =
16.2
V I N.
TIME
CA
I
INFLOW
OUTFLOW
STORAGE
(min)
(ir7/hr)
(cu +t)
(cu +t)
(cut •ft)
(ac +I_)
J
2.55
9.00
6985
-----------------------
321
6564
0.151
10 a
2.55
7.30
11169
642
10527
0.242
15
2.55
6.00
1.3770
963
13449
0.309
20
2.55
5.20
15912
1284
1.4628
0.336
25
.55
4.60
17595
.1605
15990
0.367
30
2.55
4.15
190A 9
1926
18728
0. 43.0
35
2.55
3.80
20349
2247
18102
ii.4.16
40
• . J..l
2 5C
C
', JO
�.14 �_0
21420
2
•• �68
25
5i
188J
0.433
45
2.55
3.25
22�76
2889
19487
0.447
={•a
2.55J
3.00
22950
3210
19740
0.453
cc
2.55.,J
2.80
r_r62
.-_.,c_1
20031
0. 460
60
2.55
2.60
2:?;&)68
3852
20016
✓ 0.460
2.55
2.730
24633
4494•
179
0.462
80
•y 5
• .5
• . UJ
2 5
2 L 2
Jia9 •
.,136
5
C
199J6
C
0. 4.,8
90
2.55
1.85
25475
5778
19697
0.452
100
2.55
1.70
26olO
6420
19590
0.450
110
2.55
1.55)
26007
7062
19i)25
0.437
120
2.55
1.43
26622
7704
18910
i a . 4 : 4
130
2.55
1.32
26255
8346
17909
0.411
140
2.55
1.24
26561
8988
17573
0.403
150
2.55
1.19
27311
96:0
17681
0.406
160
2.55
1.13
27662
1 i a272
17390
i a . 399
170
2.55
1.09
.29351
10914
17437
0.400
120
2.55
1.05
2891.7
1.1556
17361
0.'99
REQUIRED
DETENTION VOLUME
-
MAXIMUM
VOLUME =
20139
CU.FT.V"l
MAXIMUM
VOLUME =
0.46
AC.FT.
MASS DIAGRAM METHOD
for
DETENTION VOLUMES
PROJECT: SILVERPLUME - THIRD FILING
COMMENTS:100 YEAR DETENTION VOLUMES
SOUTHEAST DET. FOND
BASIS E.F,G,H
MAXIMUM ALLOWABLE RELEASE (CFS) =
RATIONAL- EQUATION: Q. = CIA
C= o.s0 2
c,cT= 0.625 ev
TIME of CONCENTRATION =
A(area) =
10.00 MIN.
Lƒ AC
TIME
CA
I
INFLOW
ouTELOW
STORAGE
imin,
(in/hr)
ice ft)
ico -ft.)
(ce ft) rac It,
5
2.32
9.00
6261
369
5892
0.135
!0
2.32
7.30
10156
738
9418
0.216
15
2.32
6.00
12521
1.107
!2l52
0.279
20
2.32
5.20
14469
1476
12993
0.298
25
2.32
4.60
!� 99
l845
14ls4
0.325
30
2.32
4.15
17321
221.4
16952
0.389
35
2.32
3.80
18504
2583
l592!
0.3
40
2.32
3.50
19478
2952
16526
0.379
45
5n
2.2.
z
..25
\.00
20}47
20869
3321
\690
l7026
17179
& 3,91
0.394
s§
_. :\r,2
2.30
214254os9
l6'
/.399
60
2.�
2.60
2l704® 4428
17276®
0.39773
70
2.32
2. 30
.2399
5166
0.396
80
2.\2
2:.05
2281.7
5904
16913
0.388
90
2.22
l.es
23164
6642
16522
0.379
1.00
2 2
1.70
2=651
7380
16271
0.374
I10
2.32
1.55
23721
e118
15603
0.358
120
2.32
1.45
2420E
oG56
15752
0.352
I3o
2.32
1.32
2.
9594
I4280
0.328
140
2.32
1.24
24152
10332
13C.20
0.317
Iso
2.32
1.19
24834
11070
13764
0.316
160
2.s2
I.13
25-154
11e0e
13346
0.306
170
2.32
1.09
257eo
12546
1 234
0.304
!80
2.32
1.os
26295
1. 4
l3011
0.299
REQUIRED
DETENTION
VOLUME -
MAXIMUM
VOLUME _
17366 CU.FT.�
MAXIMUM
VOLUME =
0.4o AC.
FT.
�
SYN: 87020229
^
Elevation
(ft)
77,53
78.00
79.00
79.67
80.00
SILVERPLUME - THIRD FILING
SOUTHEAST DETENTION POND
CALCULATED 04-04-1990 14:08:08
DISK FILE : B:SLPLMSEP.VOL
Planimeter scale: 1 inch = 208.71 ft,
Planimeter Area
(sq.in,) (mg.ft,)
0.00 0.00
3^420,00 3,419.99
12,380.00 12,379.96
*I* 16,136.82
�
18,170°00°' 18,169.94**
*
A1+A2+sqr(A1*A2)
Volume
Volume Sum
( sg.ft)
-----------------------------------
< co,ft>
( cu. ft)
0. 00
0.00
0.00
3"419.99
535.80
535.80
22,306.82
7,435.61
7^971.41
42,650.89
9,525.34
17^496.75
45,548.01
15,182.67
231154.0B^*
Interpolated area from closest two planirrieter readir%-gs.
2
IA = (sq.rt(Area1) + ((Ei�E1)/(E2�E1))*(sq.rt(Area2}�s�.rt(Area1>))
where.- E1, E2 = Closest two elevations with planimeter data
Ei = Elevation at which to interpolate area
Area1,Area2 = Areas computed for E1, E2, respectively
IA = Interpolated area for Ei
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2--EL1) * (Areal + Area'_;' + sq,rt.(Area1*Area2)>
where: EL1, EL2 = Lower and upper elevations of the increment
Area1~Area2 Areas computed for EL1, EL2, respectively
Volume = Incremental volume between EL1 and EL2
`^
QOND-2 Version; 2.30
S/N: S7020229
SILVERPLUME -- THIRD FILING
SOUTHWEST DETENTION POND
CALCULATED 04--04~1990 16-17-05
DISK FILE : B:SLPLMSWP.VOL
Planimeter scale: 1 inch = 208.71 ft.
Elevation
Planimeter
Area
(ft)
(sq.in.)
( og.ft)
72.50
0.00
0.00
74.00
5`292.00
5,291.98
76.00
9,162.00
9,161.97
76.34
*I*
9,952.73
77.50
12,897.00V
121B96.96
A1+A2+sqr(A1*A2>
*
Volume
Volume Sum
(sg^ft,)
( cu.ft, )
( cu. ft, )
0.00
0.00
0°00
5,291.98
2,645.99
2.645.99
21,417.07
14,278.05
16,924.S4
28,663.87
3,2 48.54 �/
20,172. 59
32~929.15
16,464.57VI
33,388.6rw� |
~ � �
Interpolated area from closest two planimeter readings.
2
IA � (sq.rt(Ar�`a1) + ((Ei-E1)/(E2�E1))*(sq.rt(Area2)-sq.rt(Area1)))
^
where: E1, E2 Closest two elevations with planimeter data
Ei Elevation at which to interpolate area
Area1,Area2 = Areas computed for E1' E2, respectively
IA = Interpolated area for Ei
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume -x- (1/3) * (EL2-EL1) * (Areal + Area2 + sq.rt.(Area1*Area2))
where: EL1^ EL2 = Lower and upper elevations of the increment
Area1,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between EL1 and EL2
CLIENT /'FaFI-S 4,cx t +O /11;2fm r---? { JOB NO.
NG PROJECT f LeAt"O'f CALCULATIONSFOR cJ Z,J, PONd (.),C
Engineering Consultants MADE BY DATE 72Z_ CHECKED BY DATE SHEET / OF _
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TMINC PROJECT U CALCULATIONS FOR
Engineering Consultants MADESY'f? DATE C
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AREA AND INLET CALCULATIONS
HYDROLOGIC RUNOFF CALCULATIONS
RATIONAL METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT: SILVERPLUME
JOB #: 367-002
ENGINEER: TMO
DATE: 07-Mar~90
CALCULATE THE 10
__________________________________________________
& 100 YEAR DEVELOPED
STORM RUNOFF
Q = CfCIA
WHERE.-
Q =
RUNOFF (CFS)
C =
RUNOFF COEFFICIENT
Cf =
RUNOFF COEFFICIENT FACTOR
A =
BASIN AREA (AC)
I =
RAINFALL INTENSITY (IN/HR)
S =
BASIN SLOPE (%)
BASIN INPUT
===========
L =
BASIN LENGTH (FT)
NAME:
A
A =
2.68
C =
0.50
Cf =
DEPENDANT ON THE
STORM FREQUENCY
L =
640 FT
I =
TO DETERMINE "I"
FROM FIG.
3-1:
RAINFALL INTENSITY
DURATION CURVE.
CALCULATE
''Tc"-
TIME OF CONCENTRATION
Tc =
Tov + Tg
WHERE:
Tov
= OVERLAND FLOW TIME
or
To
= SHALLOW GUTTER FLOW TIME
Tc =
(1.87*(1.1-Cf*C)*L^0.5>/(S^0.33)
FOR Tov,
FIND THE OVERLAND
SLOPE AND
LENGTH
Sov =
1.75 %
Lov =
40 FT
FROM FIG. 3-1: OVERLAND TIME OF FLOW CURV[--"S (ATTACHED"
Tov = 8,00 MIN
FOR Tq,
FIND THE GUTTER SLOPE AND
LENGTH AND VELOCITY
Sg
= 1.07 %
Lg
= 600 FT
FROM FIG, 3~2: ESTIMATE OF AVERAGE
FLOW VELOCITIES (USDDC
MANUAL)
V
= 2.2 FPS
To
= Lg/(60*V)
Tg
= 4.55 MIN
BASIN OUTPUT Tc = 10 MINUTE
MINIMUM REQUIRED
10 YEAR
DEVELOPED STORM
100 YEAR DEVELOPED
STORM
Cf
= 1.00
Cf = 1,25
Tc
= 27.51 MIN
Tc = 21.78
MIN
I
= 2.75 IN/HR
I = 5.00
IN/HR
/
Q
= 3.69 CFSu/
Q � 8.3S
CFS v
HYDROLOGIC RUNOFF CALCU/.ATI�NS
RATIONAL METHOD
REFERENCE: CITY OF FO9[ CbLLINS
S�ORM DRAlHA8� DESIGN MAN�AL
PROJECT: Sl\VERPLUME
JOB #: 367�002
ENGINEER: TMO
DATE: 15-Mar~90
CALCULATE THE 10
& 100 YEAR
DEVELOPED STORM RUNOFF
Q = CfCIA
WHERE:
Q =
RUNDFF (CFS)
C
COEFFICIENT
Cf
RUNOFF COEFFICIENT FACTOR
A
AREA (AC)
I
RA[NFALL INTENSITY
S =
BASIN SLOPE (%)
BASIN INPUT
L
BASIN LENGTH (FT)
��o��
oox� uus�r��pp
NAME:
A1
A
0.11
C =
0.85
Gf =
DEPENDANT ON THE
STORM FREQUENCY
S =
2.00 %
L
120 FT
I =
TO l)ETERMINE ''I/'
FROM FIG.
3~1:
RAINFALL INTENSITY
DURATION CURVE~
CALCULATE /'Tc»--
TIME OF CONCE;',ITRATION
Tc
Tov + Tg
WHE�E:
Tov
= OVERLAND FLOW TIME
or
Tg
� SHALLOW GUTTER FLOW TIME
Tc =
(1.87*(1.1-Cf*C)*L^0.5)/(S^0.33)
FOR Tov,
FIND lHE OVERLAND
SLOP'E AND
LENGTH
Sov =
0.00 %
Lov
0 FT
FROM FIG. 3-1: OVERLAND TIME OF FLOW CURVES (ATTACHED)
Tov = 0.00 M.lN
FOR Tg, FIND THE GUTTER SLOPE AND LENGTH AND VELUCITY
Sg = 2.0 %
Lg = 120 FT
FROM FIG. 3-2: ESTIMATE OF AVERAGE FLOW YELOCITIES <USDDC MANUAL>
V = 2~5 FPS
Tg Lg/(6(..)*V)
Tg � 0.80 MIN
BASIN OUTPUT Tc �
10 YEAR DEVELOPED STURM
Tc = 10.00 MIN
I 4.50 IN/HR
Q � 0.42 CFS w/
10 MINUTE MINIMUM REQUIRED
100 YEk�:ik DEVELUP6D SITORM
Cf � 1,25
Tc = 10.00 MIN
I 7.10 IN/HR
�
Q 0.83 CFS *,
HYDROLOGIC RUNOFF CALCULATIONS
RATIONAL METHOI)
REFERENCE- CITY OF F'(::)RT COLLINS
STORM DRA:INAGF.. DESIGN MANUAL_
PROJECT: SII-VERPLUME ?RD FILING
JOB #: 7_-,67-002
ENGINEER: TMO
DATE. 05—Apr-90
CALCULATE THE 10 & 1(.m) YEAR DEVELOPED STOR 1 RUNOFF
0 = Cf C I A WHERE-- G? == RUNC.IF'F= (CFS)
C = RUNOFF COEFFICIENT
Cf = RUNOFF COEFFICIENT FACTOR
A = BASIN AREA (AC)
I = RAINFALL INTENSITY (IN/HR)
S BASIN SLOPE_ (%)
BASIN INPUT L BASIN LENGTH (FT)
NAME: B
A = 1.40
C = C3.51C7
Cf = DEPENDANT ON THE STORM FREQUENCY
S = 1.71
L_ = 475 FT
I = TO DETERMINE "I" FROM FIG. -1: RAINFALL INTENSITY
DURATION CURVE. . CALCULATE "Tc "•-- TIME 01: CONCENTRATION
Tc Tcry -I• Tq W+ 41;:.RF^ l'ov == O.VERL...AND FL...OW -1 T.ME:
or, Tg rz SHALLOW GLITTER FLOW TII`11=
Tr =(.1.87#(1.1-CfCT�•L,'.t7.`i)/(S''Ci.E.?)
FOR Tov, FIND THE OVERLAND SLOPE AND LENGTH
Sov = 1.79
Lov = 145 FT
FROM FIG. 3-1- OVERLAND TIME OF' FLOW CURVES ' ATTACl-4ED )
Tov = IS.Cip MIN
FOR Tq. FIND THE GUTTER SLOPE AND LENGTH AND VELOCITY
Sri = :L . 46 %
Lq = Teti FT
FROM FIG. 3-2. ESTIMATE OF AVERAGE FLOW VELOCITIES (USDDC MANUAL',
V = 2.5 FPS
Tq _. L.q/ (6O*V)
Tq = 2.20 MIN
BASIN OUTPUT Tc = 10 MINUTE MINIMUM REDUIRED
1CU YEAR DEVELOPED STORM
Cf = I. C) C)
Tc = 2("Y. A.9 MIN vo
I - .21) IN/HRV
_ ^•.. 24 CFS v
1.00 YEAR DEVELOPED STORM
Cf 1.25 /
Tc. = 16. 22 MIN
I 80 INI/HR
n 5.07 CFS �%
HYDROLOGIC RUNOFF CALCULATIONS
RATIONAL METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT: SILVERPLUME
JOB #: 367-002
ENGINEER- TMO
DATE, 07-Mar-90
CALCULATE THE 10 & 100 YEAR
___________________________
Q = CfCIA WHERE:
BASIN INPUT
NAME: E
A = 0.66
C = 0.5O
Cf = DEPENDANT ON THE STORM
S = 1.18 %
L = 360 FT
- --
DEVELOPED STORM RUNOFF
Q�= RUNOFF (CFS)
C = RUNOFF COEFFICIENT
Cf = RUNOFF COEFFICIENT FACTOR
A =BASIN AREA (AC)
I = RAINFALL INTENSITY (IN/HR)
S = BASIN SLOPE (%)
L = BASIN LENGTH (FT)
FREQUENCY
I � TO DETERMINE "I" FROM FIG, 3~1: RAINFALL INTENSITY
DURATION CURVE. CALCULATE "Tc''- TIME OF CONCENTRATION
Tc = Tov + Tg WHERE: Tov = OVERLAND FLOW TIME
or Tg = SHALLOW GUTTER FLOW TIME
Tc =
�--------------------------------------------------------------------------
FOR Tov, FIND THE OVERLAND SLOPE AND LENGTH
Sov = 2.00 %
Lov = 40 FT
FROM FIG. 3-1t OVERLAND TIME OF FLOW CURVES (ATTACHED)
Tov = 8.00 MIN
FOR Tg~ FIND THE GUTTER SLOPE AND LENGTH AND VELOCITY
So = 1.18 %
Lg = 360 FT
FROM FIG" 3-2: ESTIMATE OF AVERAGE FLOW VELOCITIES (USDDC MANUAL)
V = 2.2 FPS
To = Lg/(60*V)
Tg = 2.73 MIN
BASIN OUTPUT Tc =
10 YEAR DEVELOPED STORM
Cf = 1.00
Tc = 20.16 MIN
I = 3.25 IN/HR
Q = 1-07 CFS
10 MINUTE MINIMUM REQUIRED
100 YEAR DEVELOPED STORM
Cf = 1.25
Tc = 15.96 MIN
I = 5.80 IN/HR
Q = 2.39 CFS
HYDROLOGIC RUNOFF CALCULATIONS
RATIONAL METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT: SILVERPLUME 3RD FILING
JOB #: 367-002
ENGINEER: TMO
DATE: 04-Apr-90
CALCULATE THE 10 & 100 YEAR DEVELOPED STORM RUNOFF
Q CfCIA WHERE: Q. = RUNOFF (CFS)
C = RUNOFF COEFFICIENT
Cf = RUNOFF COEFFICIENT FACTOR
A BASIN AREA (AC)
I RAINFALL INTENSITY (IN/HR)
S BASIN SLOPE <%>
BASIN INPUT L = BASIN LENGTH (FT)
===========
NAME: F
A 0.67
C 0.50
Cf DEPENDANT ON THE STORM FREQUENCY
S = 1.65 %
L = 335 FT
I = TO DETERMINE "I" FROM FIG. RAINFALL INTENSITY
DURATION CURVE, CALCULATE "Tc"- TIME OF CONCENTRATION
Tc = Tov + Tg WHERE: Tov = OVERLAND FLOW TIME
or Tg = SHALLOW GUTTER FLOW TIME
Tc = (1.87*(1.1-Cf*C)*L^0.5)/(S^0.33)
FOR Tov, FIND THE OVERLAND SLOPE AND LENGTH
Sov = 2.40 %
Lov = 160 FT
FROM FIG. 3-1: OVERLAND TIME OF FLOW CURVES (ATTACHED)
Tov = 17.00 MIN
FOR Tg, FIND THE GUTTER SLOPE AND LENGTH AND VELOCITY
Sg = 1.10 %
Lg = 175 FT
FROM FIG. 3--2: ESTIMATE OF AVERAGE FLOW VELOCITIES ((JSDDC MANUAL)
V = 2.0 FPS
Tg = Lg/(60*u)
Tg = 1.46 MIN
BASIN OUTPUT Tc = 10 MINUTE MINIMUM REQUIRED
============
10 YEAR DEVELOPED STORM
Cf = I. 00
Tc = 17.41 MIN +
I = 3.50 IN/HR
Q � 1.17 CFS
100 YEAR DEVELOPED STORM
Cf 1.25 /~
^�
Tc = 13.78 MIN ~
.
I = 6.10 IN/H�R *'
.�
Q 2.55 CFS
�
HYDROLOGIC RUNOFF CAL.CUL...A-1":EONS
RATIONAL METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT- SILVERPLUME :'RD FILING
JOB 1#: :67-00i 21
ENGINEER: TMO
DATE- 04-Aci -90
CALCULATE THE IC) $< l(K) YEAR DEVELOPED STORM RUNOFF
0. = CfCIA WHF...:RF: — f.•? = RUNOFF (CFS)
C = RUNOFF COEFFICIENT'
Cf = RUNOFF COEFFICIENT FACTOR
A = BASIN AREA (AC)
I = RAINFALL INTENSITY (IN!HR)
S = BASIN SLOPE (%)
BASIN INPUT L _ ?:BASIN LENGTH (FT)
NAME: G
A = 1.41
C = 0.50
Cf = DEFENDANT ON THE STORM FREQUENCY
S -- 2.50 %
L = 220 FT
1 = "1"0 DETERMINE "I" FROM FIG. .3--1:: RAINFALL INTENSITYt'
DURATION CURVE, CALCULATE "Tc"-- i'll"IE OF' CONCENTRATION
Tc = Tov + -Fa WHERE: Tov = OVERLAND FLOW 'TIME
or, 'T q = SHALLOW GUTTER FLOW TIME
Tc =(1.t37•(1.1.-CfYf.:i#L_"0.5)!(S"0. )
FOR Tov, FIND THE OVERLAND SLOPE AND LENGTH
Sov = ?-.50
Lov = 220 FT
FROM FIG. .3--1: OVERLAND TIME OF FLOW CURVES (ATTAC;l-IEL.-)
Tov = 2O.(3C) MIN
FOR Tg , FIND THE GUTTER SLOPE AND LENGTH AND VEI....0C I TY
Sg = O. ()0
Lq - C) FT'
FROM FIG. 3-2: ESTIMATE OF AVERAGE FLOW VELOCITIES (USDDC MANUAL)
V = C), O FPS
Tg = Lg/ (6.Q+V)
Ta = O.OG MIN
BASIN OUTPUT T= = 10 MINIT"I'E MINIMUM REQUIRED
10 YEAR DEVELOPED STORM
Cf = ].. (aft
Tc = iC..:7, MIN /
1 = 4. CMG IN/HF; v
Q = 2.89 CFS
10"O YEAR DEk"'E:LOPED S-fOF.M
Cf _
1.25
lr_ =
1(>.Gt)
MIN
T =
7.10
INiHR t�
Q _
6.
_'9
CFS V
HYDROLOGIC RUNOFF CAI.-.CUI....ATIONS
F;ATIONAI_ METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT. SILVERPLUME 'RD FILTNG
JOB #:=67-0C)^
ENGINEER: TMO
DATE: 04--Apr---9(_)
CALCULATE THE 10 ?, 1.00 YEAR DEVELOPED STORM RUNOFF
0 = CfCIA WHERE: 0 = RUNOFF (CFS)
C = RUNOFF COEFFICIENT
Cf = RUNOFF COEFFICIENT FACTOR
A = BASIN AREA (AC)
I = RAINFALL INTENSITY (IN/HR)
S = BASIN SLOPE (%)
BASIN INPUT L- = BASIN LENGTH (FT)
NAME: H
A -- C J. 7
C = C). SCa
Cf = DEPENDANT ON THE STORM FREQUENCY
c = 1.00) %
L = 560 FT
I = TO DETERMINE "I" FROM FIG. -1. RAINFALL. INTENSITY
DURATION CURVE, CALCULATE "Tc"-- TIME OF CONCENTRATION
Tc = ', ov + Tq_ WHERE: Tov = OVERLAND FLOW TIME
or- 7Tg == SHALLOW GUl-TER FL -OW TIME
Tc
FOR Tov, FIND THE OVERLAND SLOPE AND LENGTH
Sov = t.40 Y.
Lov = 160 FT
FROM FIG. .3-1: OVERLAND TIME OF FLOW CURVES (ATTACHED)
Tov = Ia.00 MIN
FOR Tg, FIND THE GUTTER SLOPE AND LENGTH AND VELOCITY
Sq C).3�f
Lg - 400 FT
FROM FIG. 3-2. ESTIMATE OF AVERAGE FLOW VELOCITIES (USDDC MANUAL)
V = 1 . 8 FPS
Tg = L-.g/ (6(-'*V)
Tg = -.70 MIN
BASIN OUTPUT Tc = IC) MINUTE MINIMUM REQUIRED
10 YEAR DEVELOPED STORM
Cf = 1 . C)0
Tc = 21.70 MIN ✓/
I = -'.10 IN/HRV
0. = 1.19 CFS v
100 YEAR DEVELOPED STORM
Cf = 1._'5
Tc = 21.02 MIN
I = 5. pi(-) II\I/HR
G? _2.41 CFS
HYDROLOGIC RUNOFF CALCULATIONS
RATIONAL METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT: SILVERPLUME
..SOB # : 367-0 iC
ENGINEER: TMO
DATE: 07-Mar-90
CALCULATE THE 10 8: 1.00 YEAR DEVELOPED STORM RUNOFF
-- -----------
a = CTCIA WHERE- 0 = RUNOFF (CFS)
C = RUNOFF COEFFICIENT
C{ = RUNOFF COEFFICIENT FACTOR
A = BASIN AREA (AC)
I = RAINFAL.L INTENSITY (IN/HR)
S = BASIN SLOPE (%)
BASIN INPUT L = BASIN LENGTH (FT)
NAME: I
A = C).27
C .- U . 50
Cf = DEFENDANT ON THE STORM FREQUENCY
L 65 FT
I = TO DETERMINE "I" FROM FIG. 3-1: RAINFALL INTENSITY
DURATION CURVE, CALCULATE_ "Tc"- TIME OF CONCENTRATION
Tc = Tov + To WHERE: Tov = OVERLAND FLOW TIME
or To = SHALLOW GUTTER FLOW TIME
Tc = (1 . 87* (1 . 1-Cf *C) *L"•0. 5) / (S^O..33 )
-----------------------------------------------------------------
FOR Tov. FIND THE OVERLAND SLOPE AND LENGTH
Sov = 6.30 %
Lov = 65 FT
FROM FIG. 3-1: OVERLAND TIME OF FLOW CURVES (ATTACHED)
Tov = 9.00 MIN
FOR To,
FIND THE GUTTER SLOPE AND
LENGTH AND VELOCITY
So
= 0 %
Lq
= i) FT
FROM FIG. ,— : ESTIMATE OF AVERAGE
FLOW VELOCITIES (USDDC
MANUAL)
V
= 0.0 FPS
To
= Lq_ / (6Ci*V )
To
= U., MIN
BASIN OUTPUT Tc = 10 MINUTE
MINIMUM REQUIRED
10 YEAR
DEVELOPED STORM
101.-) YEAR DEVELOPED
STORM
Cf
= 1 . O()
Cf = I.. 25
Tc
•- 10.00 MIIV
Tc = 1c), ii)
MIN
I
= 4.50 IN/HI;
I = 7„ 10
IN/HR
G!
= 0.61 CFS V
0. = 1. 20
CFS �/
HYDROLOGIC RUNOFF CALCULATIONS
RATIONAL METHOD
REFERENCE: CITY OF FORT COLLINS
STORM DRAINAGE DESIGN MANUAL
PROJECT: SIL-VERPLUME - 'RD FILING
JOB #: 367-002
ENGINEER: TMO
DATE. 09-Apr--90
CALCULATE THE 10 & 100 YEAR DEVELOPED STORM RUNOFF
Q = C•fCIA WHERE: 0 = RUNOFF (CFS)
C = RUNOFF COEFFICIENT
Cf = RUNOFF COEFFICIENT FACTOR
A = BASIN AREA (AC)
I = RAINFALL INTENSITY (IN/HR)
S = BASIN SLOPE (%)
BASIN INPUT L = BASIN LENGTH (FT)
NAME: EAST OF SILVERPLUM'1E DRIVE (HISTORIC RUNOFF)
f1 = , / 0
C = 0. 20
Cf = DEPENDANT ON THE STORM FREQUENCY
S = 1.75 Y.
L. _ 340 FT
I = TO DETERMINE "I" FROM FIG. 3-1: RAINFALL INTENSITY
DURATION CURVE, CALCULATE "Tc:"-- TIME OF CONCENTRATION
Tc = Tov + Tg WHERE: Tov == OVERLAND FLOW TIME
or, Tg SHALLOW GLITTER FLOW TIME
Tc
FOR Tov, FIND THE OVERLAND SLOPE AND LENGTH -
Sov = 1.75j %
Lov = 40 FT
FROM FIG. 3-1: OVERLAND TIME OF FLOW CURVES (ATTACHED)
Tov = 27.0o MIN
FOR Tg, FIND THE GUTTER SLOPE AND LENGTH AND VELOCITY
Sig = i;, 0(:) %
Lg = O FT
FROM FIG. T- : ESTIMATE OF AVERAGE FLOW VELOCITIES (USDDC MANUAL)
V = 0.0 FPS
Tg = Lg/ (60.X.V)
Tg = 0.0(-.) MIN
BASIN OUTPUT Tc = 1i; MINUTE MINIMUM REQUIREI}
10 YEAR DEVELOPED STORM
Cf = 1.00
Tc = 25. pig MIN
I = 2.80 IN/HR
Q = 2.07 CFS
100 YEAR DEVELOPED STORM
Cf = 1. 25
Tc = 24.37 MICA
I _ 4.70 IN/HR
Q _• 4.35 CFS
NC
Engineering Consultants
CLIENT C e A T-- 7 tc"TC-en &".3 JOB NO. 24-7 -4=2
PROJECT 511-VEM F,/JAA67 CALCULATIONSFOR
MADE BY-`�i(/\ DATE 3-/ CHECKED BY -DATE SHEETOF
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Figure 5-2
NOMOGRPAH FOR CAPACITY OF CURB OPENING INLETS IN SUMPS, DEPRESSION DEPTH 2"
J Adapted from Bureau of Public Roads Nomograph
MAY 1984 5-10 DESIGN CRITERIA
RMINC
Engineering Consultants
CLIENT G_Ita./- 7Yod ' ArAtw JOB NO. _ 34::7
PROJECT *- r CALCULATIONS FOR
MADEBYr-4- DATE `F CHECKED BY DATE SHEETOF
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DRAINAGE CR.11A MANUAL RUNOFF
0
soc
400
300
W
LL �sS
Z
200
Ltl
U r}p
2
FQ-
cn
0
100
• r
■r
APO!
VA
11010
FIGURE 371 OVERLAND TIME OF FLOW CURVES 171
70
60
50
0
W
H
Z_
40 m
Z
W
30 ~
5 -1-84
URBAN DRAINAGE 8 FLOOD CONTROL DISTRICT
DRAINAGE CRITERF MANUAL
RUNOFF
:Yi7
30
1- 20
Z
w
U
w
°' 10
Z
w
a
O 5
U
w
En 3
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co 2
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MOORE
•0 1 1•'t 2 s43 5 10 20
VELOCITY IN, 'FEET PER SECOND
FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY. FOR
USE WITH THE RATIONAL FORMULA.
*MOST FREQUENTLY OCCURRING°UNDEVELOPED"
LAND SURFACES IN THE DENVER REGION.
REFERENCE: "Urban Hydrology For Small Watersheds" Technical
Release No. 55, USDA, SCS Jan. 1975.
5 -1-84
URBAN DRAINAGE & FLOOD CONTROL DISTRICT
DRCOG
T:§D,NC
Engineering Consultants
CLIENTr—�T-
r-�
PROJECT
MADE BV/o DATE/,.CHECKED BV _
DATE
JOB NO. _36- _
OF
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RMINC PROJECT CALCULATIONS FOR (J� ��-
Engineering Consultants MADE 02LfZ DATE y SCHECKEDBY DATE SHEET-2OF
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CLIENT � "'� DJOBN-O.
RMINC PROJECT �Y/�.'^,i CALCULATIONS FOR
Engineering Consultants MADE BYT t` DATE 4 CHECKED BY DATE SHEET 3 OF
No Text
Sx
(Cross Slope)
STREET
4
S_j Longltudinai Slope)
SIDE
B
A44�
ov
0
Q L
(Gutter Flow) t- �
CARRY
3
OVER
Froude No. at This Pointy
_ 4Fw
�`'urb
r r i
QI B
(Intercepted Flow)
(Length of Opering) I
A 4j PLAN
3Icr
�' '-- G utter Depression at Inlet
P
C
SECTION A —A
0 n
H O
Na
iS
C V
li U 4 VUI Im
SECTION B-B SECTION B-B
(Straight Cross Slope) (Fort•CollirsStandard 6"Vertical CaG)
NOTE: THE FORT COLLINS STANDARDS HAVE
GUTTERS WITH CROSS SLOPES STEEPER THAN SX.
FIGURE 5-4
STANDARD CURB -OPENING INLET
MAY 1984 5-12 DESIGN CRITERIA
%DINC
Engineering Consultants
CLIENT __ C/�seJOBNO. S67 -022
tom/ C
PROJECT CALCULATIONS FOR/7i.t-t-<.( 121
4
MADE By'T74/� DATE �� CHECKED BY- SHEET ( OF
x o. o I U• i3 S cFs
Q�pR,.- - 13.-1 x p.o% " v. 13T c FS
h