HomeMy WebLinkAboutGEICO OFFICE BUILDING - PDP - PDP130039 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTDrainage Letter Report
Date: December 23, 2013
Project: Geico Office Building Project No. 959-001
Fort Collins, Colorado
Attn: Mr. Wes Lamarque
City of Fort Collins Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
Dear Wes:
This letter serves to address the stormwater impacts of the above referenced project. The site currently
consists of rooftop, concrete walks and patio, asphalt parking areas, some turf, trees, and other vegetation.
The southeastern portion of the site presently drains to an area inlet located in the center of the east main
drive aisle. The northwestern portion of the site presently drains to the center of the northern main drive
aisle and travels off-site to an inlet within the neighboring property. This area inlet releases into the City’s
storm sewer system within West Drake Road and Redwing Road. Historic drainage patterns will generally
be preserved. The total impervious area within the property boundary of the existing site is approximately
36,158 square-feet.
The proposed redevelopment will refurbish the existing parking lot and drive aisle. The existing building is
proposed to stay, but go through a complete remodel and a small addition in the rear of the building.
Concrete pedestrian connections will be added to both West Drake Road and Redwing Road. The total
impervious area within the property boundary of the proposed redevelopment is roughly 34,488 square-
feet.
To achieve water quality within the existing site, a rain garden is proposed within the southern parking
area. The rain garden will receive stormwater from the entire addition and all of the paved areas within
the southern parking lot. The calculations for the volume required for this contributing area and the
volume achieved through the design have been attached to this letter report.
The total impervious area proposed with this project will be decreased by approximately 1,670 square-feet
(36,158 – 34,488). A detailed breakdown of the existing and proposed impervious areas is attached to
this letter. Since the proposed redevelopment actually results in a lower impervious area than the historic
condition, on-site detention is not required. To incorporate some water quality within the site, a rain
garden is being proposed within the ne median.
Please do not hesitate to contact me if you have questions or require additional information.
Sincerely,
Bud Curtiss
Project Manager Cody N. Snowdon
Project Engineer