HomeMy WebLinkAboutGRANT STREET CORNERS - PDP - 20-08 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE RELATED DOCUMENTGrant Street Corners PDP
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No adverse affects to surrounding properties are anticipated from the proposed development
of this Site. Erosion control measures should be utilized to mitigate erosion and control
sediment during construction. Standard Best Management Practices should include, but are
not limited to, perimeter silt fencing, vehicle tracking control, and inlet protection.
Thank you for your time and consideration. If you have any questions or concerns, please
don't hesitate to contact me.
Respectfully,
Stewart & Associates
Consulting Engineers & Land Surveyors
Kevin Forbes r
Registered Professional Engineer
State of Colorado No. 35265
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STEWART&ASSOCIATES
Consulting Engineers and Surveyors
July 1, 2008
City of Fort Collins Stormwater Department
Attention: Glen Schlueter
P.O. Box 580
Fort Collins, CO 80522-0580
RE: Stormwater Plan — Grant Street Corners PDP
Mr. Schlueter:
Grant Street Corners PDP (Site), being a replat of lots 13 through 19, Block 1, Westlawn
Addition to Fort Collins, is located in the Northwest Quarter of Section 14, Township 7 North,
Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of
Colorado. It is bounded on the east by Grant Street, on the South by West Myrtle Street, and
on the west and north by residential properties. The total Site area is approximately 1.35
acres; containing seven existing houses, four garages, one carport, and paved sidewalks and
drives/parking areas. This project proposes to replat the seven properties and add four new
single-family residences. Three of the garages and the carport will be removed, and gravel
parking areas added at the alley along the west side of the Site. Portions of existing sidewalk
along Grant Street and on Lots 5 and 7 will be removed and new sidewalk constructed along
the entire eastern boundary. The Site is zoned NCM — Neighborhood Conservation Medium
Density District.
Portions of Lots one through four drain southward to Myrtle Street, then east to an existing
curb inlet near the intersection with Grant Street. The majority of the Site generally slopes in
a southwest -to -northeast direction, draining to Grant Street, then northward.
Addition of the four new homes (600 sf each), new sidewalk along Grant Street (1,266 sf),
and 2,452 sf of gravel parking along the alley (50% impervious) result in a total of 4,892
square feet of new impervious area. The removal of existing sidewalks (726 sf), 2,415 sf of
existing gravel area on lot seven (50% impervious), and the three garages (1,081 so results
in a total of 3,015 square feet of additional pervious area. The resulting net increase in
impervious area is 1,877 square feet.
The Site lies within the Old Town Drainage Basin of the City of Fort Collins. There are no
Master Plan Basin Recommended Improvements for the Site. It is not within any floodplain
indicated by either the City of Fort Collins or FEMA Flood Insurance Rate Maps.
Because the proposed increase in impervious area of the Site is less than 5000 square feet,
water quantity detention is not required. Water quality treatment is provided for this Site in
the Udall Natural Area's water quality treatment facility. No changes to the existing drainage
facilities are necessary, and a Grading Plan is all that is required (See sheet 4 of the Utility
Plan set).
James H. Stewart and Associates, Inc.
103 S. Meldrum Street • P.O. Box 429 • Ft. Collins, CO 80522
970/482-9331 • Fax 970/482-9382