HomeMy WebLinkAboutFORT COLLINS HOUSING AUTHORITY PUD EXPANSION - PRELIMINARY - 28-89C - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT (2)STORM DRAINAGE REPORT
FOR
FORT COLLINS HOUSING AUTHORITY P.U.D.
February 6, 1992
STEWART & ASSOCIATES, INC.
214 NORTH HOWES STREET
FORT COLLINS CO 80521
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STEWART&OSSOCIATES
Consulting Engineers and Surveyors
February 6, 1992
Ms. Susan Duba Hayes
Storm Drainage Utility
City of Fort Collins
P.O. Box 580
Fort Collins, Colorado 80522
Dear Susan:
The following is the storm drainage report for the Fort Collins Housing
Authority P.U.D. which is the site of their administrative offices at the
Southwest corner of West Mountain Avenue and Bryan Street. The address of
the site is 1715 West Mountain Avenue, and it is located in the Old Town Basin
The site is bounded by West Mountain Avenue on the North, the City Park
Softball Parking Lot and then the Larimer County Canal on the East, the City
Park Softball Fields on the South, and City Park Nine and the Trolley Barn
on the West. The site contains 0.38 acres and slopes from Northwest to
Southeast. The site has the Fort Collins Housing Authority's existing office
and maintenance building and two small sheds. The Housing Authority is
proposing to construct a 2,688 square foot addition to the building and a
concrete driveway. The increase of impervious surface is 3,438 square feet
which is 20.5% of the site. In the two—year storm, the runoff increases by
0.19 c.f.s., and in the 100—year storm, the increased runoff is 0.95 c.f.s.
The site generally drains from the West side of the site Easterly to
an existing detention pond in the existing City Park Softball Parking Lot
by sheet flow. The asphalt parking .lot has an existing area inlet in a sump
condition which discharges into the Larimer County Canal through an 8—inch
diameter corrugated metal pipe. A small area of grass at Hole One of City
Park Nine drains onto the property as the only offsite drainage.
Due to the small size of the proposed addition, relative to the large
green area of the softball fields and City Park Nine golf course, we are
requesting that no additional detention be required on this site. The runoff
will sheet flow at very low velocities over turf to the existing inlet. The
time of concentration over the turf is 24 minutes.
There is no erosion from the existing site since it is all impervious
surface or bluegrass turf. There are no public improvements to be constructed,
James H. Stewart
and Associates, Inc.
214 N. Howes Street
PO. Box 429
Ft. Collins, CO 80522
303/482-9331
Ms. Susan Duba Hayes
• Fort Collins Housing Authority P.U.D.
February 6, 1992
Page 2
except their new driveway out to Mountain Avenue. The only area that will
be disturbed is the 2,688 square foot building and the 750 square foot
driveway. The Contractor will 'je allowed seven (7) calendar days to begin
construction of the building addition and new driveway after the sod has been
removed. If construction is not underway within the time period, erosion
control measures will have to be installed per City Criteria and a security
submitted.
The historic and developed runoff calculations and the grading and
drainage plans are enclosed as a part of this report.
Sincerely,
Ri chard A. Rutherf ord, P. E. & L. S.
President
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enclosures
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COMPUTATIONS
Stewart & Associates, Inc. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331
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COMPUTATIONS
. Stewart & Associates, Inc. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331
Date 1/17%97. Client: Fur rCou fAj-r Houx,,vb Aurti »LrYSheet No. S ofmW
Chkd By: Date Project: FaP_'rCO1_L1,uf HDurl,u( AurHoe 1TV R
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