HomeMy WebLinkAboutDrainage Reports - 06/05/1989TMING
Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
303/226-4955
May 26, 1989
Ms. Susan Hayes
Stormwater Utility Dept.
City of Fort Collins
P.O. Box 580
Fort Collins, CO 80522
RE: CENTRE FOR ADVANCED.TECHNOLOGY - SECOND FILING
MINOR SUBDIVISION REVISIONS
Dear Susan:
Please find attached a copy of the grading and drainage plan for
the above referenced project. For your convenience I have also
enclosed copies of the previous preliminary and final drainage
reports completed in February of 1987.
The minor subdivision revisions shown on the new grading plan
consist principally of changes in the geometric layout of the
site and therefore have virtually no effect on the previous ap-
proved drainage approach. I trust the attached information ad-
dresses any concerns you'may have.
Sincerely,
RBD�In�c. n
Stan A Myers, P.E.
cc: Tom Livingston, Everitt Companies
035-087
Other Offices: Vail, Colorado 3031476-6340 • Colorado Springs, Colorado (719) 598-4107
RMINC
Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
303/226-4955
February 25, 1987
Mr. Bob Smith
Storm Drainage Department
City of Fort Collins
P.O. Box 570
Fort Collins, Colorado 80522
RE: FINAL DRAINAGE REPORT FOR THE CENTRE FOR ADVANCED TECHNOLOGY
SECOND FILING
Dear Bob:
Please find attached a copy of the Preliminary Drainage Report
for the Centre for Advanced Technology Second Filing. No sig-
nificant changes have occurred in the design approach and
analysis since this submittal. A more detailed final drainage
and grading plan is attached. Please contact our office if fur-
ther information is required.
Sincerely,
RBD, Inc.
Stan A. Myers, P.E.
cc: File 035-019
Other Offices: Vail, Colorado 303/476-6340 • Colorado Springs, Colorado (719) 598.4107
T3DINC
Engineering Consultants
2900 South College Avenue
Fort Collins, Colorado 80525
303/226-4955
February 5, 1987
Mr. Tom Gathmann
City of Fort Collins
P.O. Box 570
Fort Collins, CO 80522
RE: PRELIMINARY DRAINAGE REPORT FOR THE CENTRE FOR ADVANCED
TECHNOLOGY SECOND FILING
Dear Tom:
This second filing of the Centre for Advanced Technology is lo-
cated in the northeast corner of the future intersection of Cen-
ter Avenue and Shields Street. The north boundary of this site
is the New Mercer Ditch. The property is located in the South-
west Quarter of Section 23, Township 7 North, Range 69 West of
the 6th Principal Meridian.
The site currently is covered with natural Colorado field gras-
ses which slopes to the northeast at about 1%. Along with the
New Mercer Ditch that borders to the north, a small irrigation
ditch meanders through the property. When fully developed this
property will consist of business/office buildings, parking areas
and landscaped areas (see plan).
Using the most current City of Fort Collins criteria, and the ra-
tional formula a 2 year historic maximum release rate was calcu-
lated to be 1.14 cfs. With this release rate, a required pond
volume of 0.64 acre-feet was determined (see Supplementary Cal-
culation sheet). The pond and preliminary site grading are shown
on the attached drainage plan. The pond grading shown may be
modified for final submittal. The pond will temporarily dis-
charge into an overland swale which will direct flows into the
Center Avenue storm drain proposed in the Centre for Advanced
Technology Special Improvement District.
Other Offices: Vail, Colorado 303/476-6340 • Colorado Springs, Colorado (719) 598-4107
When this site drainage and grading plan and design is
implemented, drainage flows will pass through the streets and
parking areas to the pond in a safe and controlled manner.
Sincerely,
RBD�Inc�., Engineering Consultants
Stan A. Myers, P.E.
Project Manager
Brian H.
Cole
Project
Engineer
-
•`'' DATE:
PROJECT: C A T -BUSINESS PARK
. JOB NUMBER:
DESIGN ENGINEER: BC
BASIN DESIGNATION = TOTAL SITE
DETERMINE EXISTING Q FOR
2
YEAR STORM
HISTORIC RUNOFF COEFFICIENT
,2
BASIN SLOPE: 1.5
PERCENT
BASIN LENGTH 500
FEET
... AREA: 4.01 ACRES
HIST TC = 1.87*(1.1-( 1.
,2
-. ))*SORROOT 500
))/..
1.5 ^
" = 312.87992
MINUTES
- HISTORIC RAINFALL INTENSITY:.
1.421601
INCHES/HOUR
HISTORIC OUTFALL: 1.140174
CUBIC FEET
PER SECOND
DETERMINATION OF DETENTION FOND VOLUME FOR DEVELOPED CONDITIONS
DEVELOPED STORM-. 100
YEAR.STORM
.
DEVELOPED RUNOFF COEFFICIENT
.67
CCFAC = .67
1.25
3 .._+58.375
DURATION GROSS VOL.
OUTFLOW VOL.
DETENTION VOL.
MIN CU. FT.
CU. FT.
CU. FT
5 9188.5.14
342.0372
8846.478
1 t] 1.414.5. 48
624. 0745
13461.4
' 15 18014.32
1026.112
16988.21
rr
-0 2490..�.71.
2032:223
22853.49
45 29923.12
3078.335
26844.79
60 315 S.29
4104.44.7
274.5t].85
90 34094.22
6156.67
27937.55
120 3481.9.63
8202.894
26610.74
ISO-7721.27
12313.34
25407.93
"_`60 42073.73
24626..68"
17447.04
REQUIRED DETENTION VOLUME IS
27937.55
CU. FT. OR
.641359 ACF;E FEET