HomeMy WebLinkAbout215 N. COLLEGE AVENUE - PDP - 4-07 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTNorth Star Design
700 Automation Drive, Unit I
Windsor, CO 80550
LOCATION:
PROJECT NO:
COMPUTATIONS BY:
DATE:
100-yr storm, Cf =
RATIONAL METHOD PEAK RUNOFF
(100-YEAR)
215 North College Avenue
170-12
ppk
1/36/2007
1.25
DIRECT RUNOFF
I
I TOTAL
CARRY OVER
TOTAL
REMARKS
Design
Point
Tributary
Sub -basin
A
(ac)
C' Cf
(unitless)
tc,w
(min)
i
(in/hr)
Q,w
(cfs)
from
Design
Point
Q(10)
(cfs)
Q(10)tot
(cfs)
1
Existing 1
0.15
1.00
5.0
9.95
1.49
1.49
2
Proposed 1
0.15
1.00
5.0
9.95
1.49
1.49
Q=CfCiA
Q = peak discharge (CIS)
C = runoff coefficient
Cf = frequency adjustment factor
I = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres)
Flow_all.xls Q100
0
North Star Design
700 Automation Drive, Unit I s
Windsor. CO 80550
RATIONAL METHOD PEAK RUNOFF
(10-YEAR)
LOCATION: 215 North College Avenue
PROJECT NO: 170-12
COMPUTATIONS BY: ppk
DATE: 1/30/2007
10-yr storm, Cf = 1.00
DIRECT RUNOFF
TOTAL
CARRY OVER
TOTAL
REMARKS
Design
Point
Tributary
Sub -basin
A
(ac)
C' Cf
(unilless)
tc,
(min)
i
(iNhr)
Qro
(ds)
from
Design
Point
Q(10)
(cis)
Oil0)tot
(cis)
1
Existing 1
0.15
0.95
5.0
4.87
0.69
0.69
2
Proposed 1
0.15
0.95
5.0
4.87
0.69
0.69
Q=CfCiA
Q = peak discharge (cfs)
C = runoff coefficient
Ct = frequency adjustment factor
I = rainfall intensity (in/hr) from IDF curve
A = drainage area (acres) '
Flow_all.xls Q10
North Star Design
700 Automation Drive, Unit I
Windsor, CO 80550
LOCATION:
PROJECT NO:
COMPUTATIONS BY:
DATE:
5-yr storm, Cf =
RATIONAL METHOD PEAK RUNOFF
(5-YEAR)
215 North College Avenue
170-12
ppk
1 /30/2007
1.00
DIRECT RUNOFF
TOTAL
CARRY OVER
TOTAL
REMARKS
Design
Point
Tributary
Sub -basin
A
(ac)
C' Cf
(unilless)
tes
(min)
i
(in/hr)
Qs
(Cfs)
from
Design
Point
Q(10)
(Cfs)
Q(10)tot
(Cfs)
1
Existing 1
0.15
0.95
5.0
4.00
0.57
0.57
2
Proposed 1
0.15
0.95
5.0
4.00
0.57
0.57
Q=CrCiA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
I = rainfall intensity (in/hr) from OF curve
A = drainage area (acres)
Flow_all.As Q5
North Star Design
700 Automation Drive. Unit I
Windsor, Co 80550
LOCATION:
PROJECT NO:
COMPUTATIONS BY:
DATE:
100-yr storm
215 North College Avenue
170-12
ppk
1/30/2007
Cf = 1.25
TIME OF. CONCENTRATION-100-YR
SUB -BASIN
DATA
POINT(ac)
DESIGNdExisdng
Area
INITIAL/OVERLAND
TIME (tl)
C'Cf Length
(ft)
Slope
(%)
ti
Imin)
TRAVEL TIME GUTTER OR CHANNEL FLOW
(tt)
Length Slope n Vel. it
(ft) (%) Manning(Ws) (min)
rough.
lc=
U. . ft
tc CHECK
(URBANIZED BASIN)
Total L' tc=(g180)+10
(it) (min)
FINAL
lc (10)
(min)
REMARKS
10.15
1.00
25
1.0
0.9
65.0
1.0
0.016
20
0.54
1.4
90
10.6
5.0
0.15
1.00
25
1.0
0.9
65.0
1.0
0.016
2.0
0.54
1.4
1 90
10.5
5.0
EQUATIONS:
tc=ti+It
ti=[1.87(1.1- CC, )Lo.5]1S.1I7
It = LNel.
final tc = minimum of [li + lt] or the [urbanized basin check]
Flow_all.xls TOC-100
North Star Design
700 Automation Drive, Unit I
Windsor, Co 80550
LOCATION:
PROJECT NO:
COMPUTATIONS BY:
DATE:
10-yr storm
TIME OF CONCENTRATION -10-YR
215 North College Avenue
170-12
ppk
1/30/2007
Cf = 1.06
SUB -BASIN
DATA
DESIGN SUBBASIN(s)
POINT
Area
(ac)
INITIAL /OVERLAND
TIME (ti)
C Length
IN
Sbpe
(%)
ti
(min)
TRAVEL TIME I GUTTER OR CHANNEL FLOW
00
length Slope n Val. a
(It) (°k) Manning (fils) (min)
rough.
tc =
ti+It
tc CHECK
(URBANIZED BASIN)
Total tc=(V180)+10
00 (min)
FINAL
tc (10)
(min)
REMARKS
1
Existing 1
0.15
0.95
25
1.0
1.4
65
1.0
0.016
2.0
0.54
1.9
90
10.5
5.0
2
Proposed 1
0.15
0.95
25
1.0
1.4
65
1.0
0.016
2.0
0.54
T
90
10.5
5.0
EQUATIONS:
tc = ti + tt
ti=[1.87(1.1-CCt)LO'S]/S1r3
tt = Wel.
final tc = minimum of the [ti + tt] or the [urbanized basin check]
Flow all.xls TOC-10
North Star Design
700 Automation Drive, Unit I
Windsor, CO 60550
LOCATION:
PROJECT NO:
COMPUTATIONS BY:
DATE:
PRESTON HILTON
RUNOFF COEFFICIENTS & % IMPERVIOUS
215 North College Avenue
170-12
ppk
1/30/2007
Recommended Runoff Coefficients & % Impervious from
Table 3-1 of the Urban Drainage Criteria Manual
or Table 3-3 of the Fort Collins Drainage Manual.
Asphalt
Gravel
Roof
Landscape
Runoff
%
coefficient
Impervious
C
0.95
100
0.50
40
0.95
90
0.25
0
SUBBASIN
DESIGNATION
TOTAL
AREA
(ac.)
TOTAL
AREA
(sq.tt)
ASPHALT
AREA
(sq.ft)
GRAVEL
AREA
(sq.ft)
ROOF
AREA
(sq.ft)
LANDSCAPE
AREA
(sq.ft)
RUNOFF
COEFF.
(C)
Impervious
Existing 1
0.15
6,507
0
0
6,507
0
0.95
90.0
Proposed 1
0.15
6.507
0
0
6,507
0
0.95
90.0
Equations
- Calculated C coefficients & % Impervious are area weighted
C=E(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
E
Flow_all.xls Cval
0
North Star
�`► design, inc.
January 22, 2007
Glen Schlueter
City of Fort Collins
700 Wood Street
Fort Collins, CO 80524
Mr. Schlueter:
This letter is intended to address the drainage associated with the redevelopment of 215
North College Avenue in Fort Collins. The owner is proposing to demolish the existing
building which covers all of Lots 4 and 5 in Block 22 and construct a new building that
covers the same area.
The existing runoff from the site drains to the alley west of the site and into College
Avenue east of the site. Attached are calculations showing the runoff from the site in the
5, 10 and 100 year storms in both the existing condition and the proposed condition.
Detention and water quality are not currently provided for the site and no new facilities
are proposed. During construction, it is proposed to protect downstream inlets from silt
using wattles.
Please call if you
or questions.
700 Automation Drive, Unit I Windsor, Colorado 80550
970-686-6939 Phone 0 970-686-1 188 Fax