HomeMy WebLinkAboutDrainage Reports - 09/28/2005NORTHERN
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SERVICES, INC. Fin RP,-, pate�-w
Basil Hamdan
City of Fort Collins Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
April 5, 2005
Re: Final Drainage Report for Old Town Commons
Dear Basil,
This letter is to summarize the drainage concepts for the proposed Old Town
Commons project located at the southeast corner of the intersection of Smith Street -and Olive
Street. The project is located within the Old Town Master Drainage Basin.
The project will involve the demolition of the existing house and the construction of
3 smaller condominiums along with a gravel parking area along the alley running parallel to
Smith Street. The adjacent alley (roughly 65-feet) will be paved. With the proposed
construction, impervious area will be added to the site. Based on the Old Town Drainage
Master Plan, specifically, Section R 3.1 of the "Technical Documentation for the Selected
Plan of Improvements for the Old Town Basin" dated September 2, 2003, as long as the
impervious area to be added does not exceed 5000 square feet, detention is not required for
the site. Based on the attached site impervious area comparison sheet, the site has an existing
impervious area of 3352 square feet and a proposed impervious area of 8307 square feet.
The proposed increase in impervious area is 4955 square feet, thus the site is exempt from
detention. .
Drainage from this site is routed via an existing storm line system under Riverside
Avenue to a regional water quality pond; thus water quality measures are not necessary.
Historically, drainage from the site was directed into Smith Street and Olive Street
and was conveyed east in Olive Street gutter into the west gutter of Riverside Avenue. Flows
in Riverside are conveyed approximately 200 feet southeast to Stover Street. From this point,
flows are conveyed south in Stover Street approximately 300 feet to an existing combination
inlet at the northeast corner of Stover Street and Magnolia Street.
As can be seen on the grading plan for the site, the existing drainage patterns are
maintained, sending drainage from the west side of the lot into Smith Street, and drainage
from the north side of the lot into Olive Street.
If you have any questions regarding drainage for this site, please do not hesitate to
contact me at 221-4158 ext. 106.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
Aaron Cvar, P.E.
Senior Engineer
420 SOUTH HOWES, SUITE 202 / FORT COLLINS, COLORADO 80521 / 970.221.4158 / FAX 970.221.4159
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