HomeMy WebLinkAboutZIEGLER - HARVEST PARK ODP - ODP120004 - REPORTS - DRAINAGE REPORT (5)1
March 18, 2013
Mr. Wes Lamarque
City of Fort Collins Stormwater
700 Wood Street
Fort Collins, CO 80522-0580
RE: Overall Development Plan Drainage Report for Ziegler Mixed Use
Dear Wes,
I am pleased to submit for your review and approval, this Overall Development Plan (ODP)
Drainage Report for the Ziegler Mixed Use development. The Ziegler Mixed Use development
is located in southeast Fort Collins. More specifically it is located in the Southwest Quarter of
Section 5, Township 6 North, Range 68 West of the Sixth Principal Meridian, in the City of Fort
Collins, Larimer County, Colorado. See the location map in Appendix A.
The project site is on the west side of Zeigler Road and the property will be split down the
middle by the extension of County Fair Lane. The project is bounded on the north and west by
Harvest Park Subdivision, on the south by McClelland’s Channel, and on the east by Ziegler
Road.
The property consists of approximately 4.08 acres of land which will be separated into two
parcels by the County Fair Lane right-of-way. Both parcels are owned by the DP Investment
Group. The parcel to the north will be developed with two commercial buildings at a maximum
of 5,500 square feet with associated drives and parking lot. The northern parcel could also be
developed as multi-family residential with twelve units (two buildings). The southern parcel will
be developed as multi-family residential with twenty-four units (four buildings) and associated
drives and parking.
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In general the existing site drains from north to south and drains into McClelland’s Channel on
the south end of the property. There is approximately 2.05 acres to the north of the site that
drains through the property as well. Upon development this existing off site drainage will be
routed through the site and continue to discharge into McClelland’s Channel. Please refer to the
attached Conceptual Drainage Plan for on-site and off-site major basin delineation.
During conceptual review of this development the City determined that detention is not required.
There will be a water quality pond located at the southern end of the south parcel as well as
several small rain gardens to achieve the required water quality capture volume.
Upon development flow from the northern parcel will be collected and conveyed south across the
southern parcel where it will discharge into the water quality pond. Runoff from the northern
parcel frontage along Ziegler will follow existing flow paths south along the curb and gutter
where it will be intercepted by a proposed inlet in the low point of County Fair Lane.
Approximately 85% of the runoff from the proposed extension of County Fair Lane will flow to
the east and be collected in proposed inlets at the low point in County Fair Lane. The other 15%
will flow off site to the west to a pair of existing inlets in the Harvest Park Subdivision. This
flow will be conveyed to the Harvest Park Pond and was accounted for in the Harvest Park
Drainage Report.
Flow from the southern site will be collected and conveyed to the water quality pond as well.
There will be two rain gardens that will treat the roof runoff of the proposed buildings on the
south parcel. The use of the rain gardens will help reduce the size of the water quality pond.
Runoff from the southern parcel frontage along Ziegler will follow existing flow paths south
along the curb and gutter where it will be intercepted by an existing inlet at the low point of
Ziegler Road just north of the McClelland’s Channel bridge. The existing inlet discharges
directly into McClelland’s Channel so the Ziegler frontage south of the County Fair Lane
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intersection will not pass through the water quality pond.
In order to account for the runoff on the site that is unable to reach the water quality pond, the
proposed inlets in County Fair Lane will intercept additional runoff from Ziegler road. The
existing high point in Ziegler is approximately 850 feet north of the proposed site northern most
property line. After being collected in the proposed inlets in County Fair Lane, this runoff will
be conveyed through the site and discharge into the water quality pond.
The water quality pond will be designed to treat the required water quality capture volume based
upon the development of the proposed site. All flows that are conveyed to the water quality
pond, including off-site flow, that exceed the water quality capture volume will flow over a
spillway and discharge directly into McClelland’s Channel.
I appreciate your time and consideration in reviewing this submittal. Please call if you have any
questions.
Sincerely, Reviewed By:
Skylar Brower, P.E. Robert Almirall, P.E.
Colorado Professional Colorado Professional
Engineer No. 44248 Engineer No. 33441