HomeMy WebLinkAboutDrainage Reports - 10/24/1996Mr. Basil Hamdan
Storm Water Utility
City of Fort Collins
P.O. Box 580
Fort Collins, CO 80522
Dear Basil,
STEWAU&kSSOCIATES
Consulting Engineers and Surveyors
September 9, 1996
re: Building addition at 216 Hemlock Street for the Phase 2 Company
The existing building is approximately 14,500 square feet and the proposed addition
is about 1,700 square feet. The building addition will be constructed over existing asphalt pavement.
The site is located on the north side of Hemlock Street about 400 feet west of North College
Avenue. The site is located in the Dry Creek flood plain. The existing floor elevation is 4972.0 and
the 100 year flood water elevations is 4874 per FIRM map 080102-0004-C revised March 18, 1996.
The site is in Flood Zone AE. It is allowable to construct the new addition floor elevation at the
existing floor elevation since the addition is a small percentage of the total floor area.
The new addition will not increase the runoff over that which now (historically) exists.
The flow patterns will not be altered by the new addition. The roof drainage from the new
addition will follow the same flow route as the runoff from the existing asphalt which is being covered
by the building addition.
The runoff from the site is to the south and east along Hemlock Street to existing curb inlets
located in the north and south gutters of Hemlock and just west of College Avenue.
The construction of the proposed building addition will make no change in the existing stormwater
runoff and will cause no adverse conditions.
The construction of the proposed addition will cause minimal erosion problems. The building
addition will have a concrete slab floor. The removal of the existing asphalt in preparation for the
slab floor will probably cause some dirt to be tracked onto the existing asphalt driveway. This dirt
should be swept up by the contractor as it occurs, but as a guard against this dirt being washed east
along Hemlock and into the storm drain system, a gravel filter should be place in the north gutter of
Hemlock just east of the west driveway into the site.
The erosion control collateral at this site will be the minimum 1000 dollars.
A copy of the FIRM map for this site is included along with a plan of the area which shows the
proposed construction and the surrounding areas.
Please call if you require additional information on this project.
Sincerely,
4
A�
Phillip I. Robinson P.E. & L.S.
James H. Stewart
rrc
and Associates. Inc.
103 S. Meldrum Street
P.O. Box 429
Ft. Collins, CO 80522
970/482-9331
Fax 970/482-9382
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