HomeMy WebLinkAboutDrainage Reports - 09/13/1988Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
303/226-4955
August 5, 1988
Ms. Susan Hayes
City of Fort Collins
P.O. Box 580
Fort Collins, Colorado 80522
RE: FINAL DRAINAGE REPORT FOR THE TENTH FILING
OF THE CENTRE FOR ADVANCED TECHNOLOGY
Dear Susan:
The location for the Tenth Filing of the Centre for Advanced
Technology is at the southeast corner of the intersection of
Centre Avenue and Shields Street in Fort Collins, Colorado. More
specifically this site is located in the southwest quarter of
Section 23, Township 7 North, Range 69 West of the 6th Principal
Meridian.
This site, as it currently exists, is an open field sloping to
the northeast at about 0.80%. Some landscape berms have been
recently constructed on the west side of this property and will
remain in the developed state. When developed, this site will be
occupied by a retail building, convenience store and a car wash
with parking and drive areas.
The drainage for this site will flow totally into a temporary
detention pond at the southeast corner of this site. The pond
volume, based on the following calculation sheet, is to be at
least 17,104 cu.ft. Outfall from this pond calculated at a re-
quired rate of 0.68 cfs, will flow out of an area inlet, in the
middle of the pond, and into the Centre Avenue storm drainage
system. This approach conforms to the drainage master plan in
the Drainage Report for the Centre for Advanced Technology Spe-
cial Improvement District, February 1987, by RBD, Inc. Engineer-
ing Consultants.
Other Offices: Vail, Colorado 303/476-6340 • Colorado Springs, Colorado 303/574-3504
Construction of the storm drainage improvement called for in this
report should provide for the safe conveyance of storm water
flows according to City of Fort Collins Drainage Specifications.
Sincerely,
RBD, Inc.
Stan A. Myers, P.E.
Project Manager
cc: 035-064
18060
rd
is •hWa
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PROJECT- CENTRE._' IoTH FILING
JOB MUMBER: O35-064
DESIGN ENi.:iINEER-. SAM
BASIN DESIGNATION = B1-A
DETERMINE EXISTING 0 FOR 2 YEAR STDRm
HISTORIC RUNOFF COEFFICIENT .2
BASIN SLOPE: .6 PERCENT'
BASIN LENGTH 250 FEET
AREA: 2.375 ACRES
HIS'T TC = i.87(1.1-( 1 ))*SORRoo'r 250 I " 3 _
HISTORIC RAINFALL. INTENSITY:
HIS'CORIC OUTFALL: .6837153
>/ .6
31.54494 MINUTES
1.4:39401. INCHES/HOUR
CUBIC FEET PER SECOND
DETERMINATION OF DETENTION POND VOLUME FOR DEVELOPED CONDITIONS
DEVfi:L.OF'ED STORM:
100
YEAR STORM
DEVELOPED RUNOrF COEFFICIENT
.69
CCF AC = .6?
1.25
aF
2. 3 75
2. 0484.38
Dl.1RAI'ION
GROSS VOL„
OUTFLOW VOL-.
DETENTION VOL.
MIN
CU. FT'.
CU. FT.
CU. FT
5
5604.525
205.1146
57599.41
10
8628.019
410.2292
8217.79
15
10987.82
615.3438
10372.48
0
1.5191.21
1230.688
13960.53
47!
1825J.58
1646. 032
16405.55
60
19247..12
2461.375
1.6785.74
90
20795.74
:3692.063
1710::.67
120
21.233.2
4922.751
16315.45
ISO
23OOS.05
7384.126
1562.3.92
'• 60
25662. 8:3
14768. 25
:10894. 57
REOUIRED DETENTION
VOLUME IS
1710.3.67
CU. FT. OR
.3926463
ACRE FEET
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