HomeMy WebLinkAboutGATEWAY TO HARMONY ROAD PUD - PRELIMINARY - 1-88A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT•
STEWART8&SSOCIATES
Consulting Engineers and Surveyors
December 30, 1987
Ms. Susan Hayes
Storm Drainage Department
City of Fort Collins
P.O. Box 580
Fort Collins, Co. 80522
Dear Susan:
This is the preliminary drainage report for "The Gateway At Harmony
Road P.U.D." which is Lot 1, Harmony P.U.D. and is located at the
Northwest corner of South College Avenue and Harmony Road. It is bordered
on the West by Mason Street, on the North by Kensington Drive, on the
East by South College Avenue and on the South by Harmony Road. The site
drains from Northwest to Southeast at approximately 1.4% slope. The
site has an existing ground cover of native grasses and has several trees
and an old concrete foundation along College Avenue.
An existing,42-inch R.C.P. storm drain lies along the West side
of College Avenue. It is known as the Mason Street Interceptor and drains
South to Mail Creek. The proposed P.U.D. was a part of the improvement
district which constructed the Mason Street Interceptor and therefore
can release into it at a rate of 0.5 cubic feet per second per acre of
land. The net area of the P.U.D. is 4.516 acres and therefore the
allowable release rate is 2.26 cubic feet per second.
The volume of detention required was determined by using a mass
diagram and detaining the difference between the 100 year developed storm
and the 2.26 cubit feet per second release rate.
The off site runoff is carried to the Mason Street Interceptor in
the existing and proposed curb and gutter and does not enter the proposed
P.U.D. It enters at existing inlets.
The site is proposed to have fast food, retail, convenience and
auto related commercial uses and the following is a breakdown of the
ground cover.
Building
Driveways and Parking
Open Space
Total
James H. Stewart
and Associates, Inc.
214 N. Howes Street
PO. Box 429
Ft. Collins, CO 80522
303/482-9331
28, 520
S.F.
14. 5%
95,165
S.F.
48.4%
73,032
S.F.
37.1%
196,717
S.F.
100%
E
•
The runoff coefficient is therefore 0.74. The detention required
is then 30,996 cubic feet.
The detention will be provided on each of the lots in the asphalt
parking areas and will be released into the Mason Street Interceptor
at one new manhole.
If you have any questions regarding this preliminary drainage report
and prelimary drainage and grading plan, please call.
Sincerely,
Richard A. Rutherford, P.E. & L.S.
President
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