HomeMy WebLinkAbout3009 S TAFT HILL RD SINGLE FAMILY HOME - FDP190027 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTLand Surveying • Land Development • Civil Engineering • Building Design & Development
(720) 689‐7324
PO Box 441730
Aurora, CO 80044
October 27, 2019
Revised November 30, 2019
Revised May 4, 2020
Dustin Couture
3009 Taft Hill Rd.
Fort Collins, CO 80526
RE: Drainage Summary for single family residence proposed to be constructed at 2120 Falcon
Drive, in Fort Collins, Colorado.
Mr. Couture,
Per your request, Prism Design & Consulting Group has performed an analysis of anticipated
stormwater runoff, comparing existing conditions to proposed conditions. The proposed
development includes the construction of a new 4,470 square foot (SF) 1‐story single family
residence with a 1,335 SF garage. A gravel driveway will be constructed to the new residence.
To facilitate the new driveway, which will be generally in the footprint of the existing driveway,
two existing outbuildings will be removed and potentially relocated to a new spot on the
property. This drainage analysis assumes that the existing buildings will indeed be replaced in‐
kind.
The total area of the property is approximately 181,800 SF (4.17 acres). Historically, the total
weighted imperviousness is 4.8%, with a 5‐year storm runoff of 1.10 cubic feet per second (cfs),
and a 100‐year storm runoff of 3.62 cfs. The proposed imperviousness is 9.1%, with a 5‐year
storm runoff rate of 1.54 cfs, and a 100‐year storm runoff rate of 4.61 cfs. The Spring Creek
Drainage Master Plan assumed no less than 30% impervious area for any developed area. In our
opinion, increase in runoff from the proposed development will be within acceptable limits.
This site does not lie within a designated flood plain, as observed on Map Number 08069C0986G,
effective 5/2/2012.
Please feel free to call if you have any questions.
Sincerely,
Brian Johnson, P.E.
Prism Design & Consulting Group