HomeMy WebLinkAboutCULTIVATION FACILITY (5608 S. COLLEGE AVE.) - PDP150004 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTJanuary 14, 2015
Wes Lamarque
City of Fort Collins Utilities
700 Wood St.
Fort Collins, CO 80521
RE: Drainage Letter for Elite Green Organics
This letter is in regards to 5608 South College Avenue, more specifically the historic drainage patterns
and any effects the proposed change of use may have on the current conditions. The project site is Lot 1
of South 13 Subdivision located in the northwest quarter of Section 12, Township 6 North, Range 69
West of the 6th Principal Meridian, City of Fort Collins, Larimer County, Colorado. The site is currently
bounded to the north by open space, to the east by a vacant lot, to the south by a retail building and to
the west by U.S. 287 Frontage Road.
The site currently consists of a combination of concrete, gravel, and natural areas with one existing
structure located on the western portion of the lot. There are four concrete parking areas located at the
front of the building with concrete area also located to the south of the building. An existing gravel
drive travels around the north and east of the current building. The remaining area to the east of the
building is native vegetation. The site drainage is divided to the east and west by a ridge line running
north and south. The stormwater routed to the west is conveyed overland from south to north through
a concrete chase connecting the two current parking areas. The stormwater is discharged to the west
undetained. The stormwater routed to the east is conveyed via overland flow and discharged
undetained at the northeast corner of the site. The site is currently 46 percent impervious.
The proposed change of use will not alter the existing drainage patterns of the site. The area draining to
the east will remain as existing with no proposed improvements. All proposed improvements are
located within the area draining to the west and consists of an additional sidewalk and handicap ramp
and the elimination of both the northern and southern parking areas in front of the building. The
existing concrete chase will be extended to the south and north to maintain the drainage connectivity
between the northern and southern concrete areas. Both discharge points will remain at existing
locations. The proposed site is calculated at 44 percent impervious, with a net loss of 2 percent. By
eliminating 2 percent of the impervious area, the site will have no adverse effects on any existing
drainage systems or adjacent properties and will decrease in overall runoff quantities.
If you should have any questions, please feel free to contact me at 970.221.4158, extension 115.
Sincerely,
Cody Snowdon, EI Roger Curtiss, PE
Project Engineer Vice President
Character of Surface
Percent
Impervious*
Streets, Parking Lots, Roofs, Alleys, and Drives:
Asphalt ……....……...…...…...………………………………………….. 100.00%
Concrete …….......…….……………….………………………………… 90.00%
Gravel ……….………….………………………………………………….. 40%
Roofs …….…….………………………………………………………….. 90%
Lawns and Landscaping
Sandy Soil ……..………………………………………………………….. 0%
Clayey Soil ….….……….…………………………………………………. 0%
Basin ID Basin Area
(sq. ft.)
Basin Area
(acres) Area of Concrete
Streets, Sidewalks
(sf)
Area of Roofs
(sf)
Area of
Gravel
(sf)
Area of Vegetated
Surfaces
(sf)
Percent
Impervious
H1 18,626 0.428 4,644 3,600 2,782 7,600 46%
P1 18,626 0.428 4,210 3,600 2,782 8,034 44%
Runoff Coefficients are taken from Table RO-5 of the Urban Drainage and Flood Control District Drainage Criteria Manual (06/2001)
HISTORIC RUNOFF COEFFICENTS
* Percent Impervious
values are taken from
Table RO-3 of the
UDFCD Drainage Criteria
Manual (06/2001)
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