HomeMy WebLinkAboutED CARROLL MOTORS LOT EXPANSION - PDP - 5-98A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTV
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14,877 cubic feet. There will be extended detention in the pond adjacent to the East property line.
The detention .pond will discharge at 0.45 c.f.s. in a 15 inch concrete storm drain to an existing storm
manhole in the driveway of the existing office building in the McClelland Office Park P.U.D.
EROSION CONTROL:
The wind and rainfall erodibility is moderate. A silt fence will be constructed along the North
and East boundary lines of the site before construction begins. The pond at the East property line
will be graded and the discharge pipe will be constructed at the beginning of the project. A sediment
trap will be placed at the outlet of the pond until the water quality box is completed. The contractor
will remove any mud off of McClelland Drive daily.
The stormwater runoff calculations and the erosion control calculations and the water quality
calculations are enclosed as a part of this drainage report.
This drainage report and the design of the drainage system are in compliance with the City
of Fort Collins Storm Drainage specifications and criteria. If you have any questions regarding this
report, please call.
Sincerely,
Richard A. Rutherford, P.E. & L. .
RAR/meh
$TEWARTMSSOCIATE$
February 11, 2002 Consulting Engineers and Surveyors y
Mr. Basil Harridan
Storm Water Utility
City of Fort Collins
P.O. Box 580
Fort Collins, CO80522-0580
!� Dear Basil,
The following is the Final Drainage Report for Ed Carroll Motor Company, Inc. Subdivision,
Second Filing, which is situate in the Northeast 1/4 of Section 26, Township 7 North, Range 69 West
F of the 6th P.M., City of Fort Collins, County of Larimer, State of Colorado. The site was a part of
McClelland Office Park P.U.D. and is now being replatted.
The site is in the Foothills Basin and contains 1.48 acres. It is zoned C-Commercial and it will
be developed as an automobile storage area and display area.
The site is bounded on the South by an existing Ed Carroll Motor Company storage area and
on the West by McClelland Drive and on the North by an existing office building in the McClelland
'- Office Park P.U.D. It is bounded on the East by a commercial building in Palmer Plaza.
The site slopes from West to East at an approximate slope of 2.5%. The existing ground
cover is grass and weeds.
The McClelland Office Park has an existing storm drainage system that was partially
completed for the existing office building to the North of the Ed Carroll Motor Company site. This
site will discharge into the existing storm drain manhole near the Northeast corner of this site at a
two-year historic rate.
The historic site is 1.48 acres and is divided into two sub -basins. Historic Sub -Basin I is the
East half of McClelland Drive and contains 0.11 acres. The Developed Sub -Basin I is the same area.
The two year runoff rate is 0.30 c.f.s. and the 100 year runoff rate is 1.09 c.f.s. The runoff in Sub-
Basin I flows North in the East gutter of McClelland Drive and is not detained.
Historic Sub -Basin II contains 1.37 acres and is the undeveloped site. The two-year historic
rate of runoff is 0.45 c.f.s. and the 100-year runoff rate is 2.07 c.f.s. The runoff from the historic
Sub -Basin II flows from West to East and sheet flows onto the National Subdivision.
Developed Sub -Basin II contains 1.37 acres also. The site will be paved for automobile
storage and there are a number of islands for landscaping. The runoff coefficient for the developed
site is 0.80. The 2-year runoff rate is 2.93 c.f.s. and the 100 year rate is 13.63 c.f.s. The runoff will
be detained on site in part of the parking lot and in a detention pond in an island along the East
property line. The detention volume required is 14,832 cubic feet for the difference between the 2
year historic volume and the 100 year developed volume. The amount of detention provided is
James H. Stewart and Associates, Inc.
103 S. Meldrum Street • P.O. Box 429 • Ft. Collins, CO 80522
970/482-9331. • Fax 970/482c9382
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TABLE OF CONTENTS
1
Vicinity Map
2-3
Teat of Report
4-7
Stormwater Runoff Calculations
8
Drainage Table
9-10
Detention Mass Diagram & Pond Volume Table
11
Orifice Sizing Calculations
12-15
Erosion Control Calculations
16-18
Extended Detention Calculation
Pocket
Grading, Drainage & Erosion Control Plan
FINAL DRAINAGE REPORT
FOR
ED CARROLL MOTOR COMPANY, INC.
SUBDMSION, 2ND FILING
FOOTHILLS BASIN
PREPARED FOR
ED CARROLL MOTORS
FEBRUARY 11, 2002