HomeMy WebLinkAboutDrainage Reports - 07/22/2011City of Ft. Collins Anprov d Pians
App BY
March 10, 2011
Project No. 2536-01-11
Glen Schlueter
City of Ft. Collins Stormwater Utility
P.O. Box 580
Ft. Collins, Colorado 80524
Re: Pura Vida Place (518 West Laurel Street); Fort Collins, Colorado
Final Drainage Report
Dear Mr. Schlueter,
SHEAR
ENGINEERING
This letter serves as the final drainage report for Pura Vida Place (518 West Laurel Street). The
site is currently developed and is planned to change use from its current restaurant use to Student
Apartments. This letter documents the historic impervious area and the proposed impervious
area. Your conceptual review comment in a letter dated December 6, 2010 from the City of Fort
Collins states:
1. It is important to document the existing impervious area since drainage requirements and
fees are based on new impervious area. An exhibit showing the existing and proposed
impervious areas is required. It doesn't appear that there will be an increase in impervious
area; however in the Old Town drainage basin a drainage and erosion control report and
construction plans are required if there is an increase in impervious area greater than 5000
square feet.., They must be prepared by a Professional Engineer registered in Colorado. When
there is less than 5000 square feet of new impervious area, a drainage letter should be
sufficient to document the existing and proposed drainage patterns. A grading and erosion
control plan is required as part of the construction plan set even if there isn't an increase in
impervious area.
Impervious areas are slightly reduced with the redevelopment of this site. Since improvements
are modified from the back of the existing curb and gutter along West Laurel Street, the limits of
comparison of impervious areas has been provided from the back of the existing curb and gutter
along West Laurel Street to the existing south edge of the alley pavement to the north. The edge
of the alley pavement is approximately the north boundary of the project site.
Attached are exhibits documenting impervious areas for both the historic condition and the
proposed condition. Historic conditions are documented on an Alta Survey prepared by Northern
Engineering Services. The Alta Survey was included in the Final Utility Plans prepared by Shear
Engineering Corporation for reference.
The impervious area in the historic condition is 35,331 square feet (77%). The impervious area
in the proposed developed condition is 32,392 square feet 71%. There will be a reduction in
impervious area.
4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 Fax (970) 282-0311 www.shearenginecring.com
Page 2
March 10, 2011
Project No. 2536-01-11
Re: Pura Vida Place (518 West Laurel Street); Fort Collins, Colorado
Final Drainage Report
The following is a summary of the historic and proposed impervious areas:
Item
Historic
Proposed
(SF)
(SF)
Concrete
5,201
4,454
Pavement
23,691
14,059
Building
6,439
13,879
Totals
35,331
32,392
Total area analyzed
45,748
45,748
Percent impervious
77%
71 %
Peak flows have been reduced at the alley in the developed condition due to a smaller
contributing area and a smaller Mannings coefficient. Refer to attached exhibits. Peak flows have
been slightly increased at West Laurel Street in the developed condition due to a larger
contributing area. Refer to attached exhibits.
Water Quality will not be provided with this development. The site is part of the Water Quality
Basin serviced by the Udall Water Quality area near the Ranch -Way feeds site near Willow
Street and Linden Street. Refer to attached exhibit.
If you have questions, please call at (970) 226-5334.
1a
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Brian-W. Shear,
Shear Engineering Corporation
BWS / me
attachments
cc: Charles Bailey; Catamount Properties Ltd.
Odell Architects P.C.
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14,058.92 S.F.
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13,879.28 S.F.
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4,454.39 S.F.
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32,392.59 S.F.
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