HomeMy WebLinkAboutDrainage Reports - 05/05/2018City of Ft. Collins, rave Plans
imNORTHERN Approved By
ENGINEERING Date —
Drainage —
Drainage Letter
Date: May 4, 2018
Project: The Preserve at Fort Collins PUD Project No. 1449-001
Minor Amendment
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 Preserve at Fort Collins PUD Minor
Amendment. The site currently consists of rooftops, concrete walks, asphalt parking areas, turf,
trees, and other vegetation. This proposed amendment intends to add additional parking spaces,
update the entrance to the clubhouse, expand the fitness room, and add a bike pavilion.
Per City of Fort Collins Stormwater Criteria, the maximum net increase in imperviousness without
addressing downstream impacts is 1,000 Square Feet (SF). As a result, the proposed
improvements adhere to this criterion using permeable pavers to reduce the net increase in
impervious area. A summary of the calculations for the impervious areas is provided below:
The proposed plan indicates approximately 2,752 SF of either concrete or asphalt demolition.
There is approximately 2,835 SF of either proposed concrete, asphalt, or rooftops and
approximately 1,636 SF of proposed permeable pavers. The proposed permeable pavers have an
imperviousness of approximately 40%.
— 2752 + 2835 + 0.40(1635) = 738 SF net increase
In conclusion, the net increase in imperviousness is approximately 738 SF, or less than the 1,000
SF maximum increase before analysis of downstream impacts is required.
Please do not hesitate to contact me if you have questions or require additional information.
Sincerely,
Danny Weber, PE
Project Engineer
514018
FORT COLLINS: 301 North Howes Street, Suite 100, 80521 1970.221.4158
GREELEY: 820 81" Street, 80631 1970.395.9880 1 WEB: www.northernengineering.com