FLOOD11444 ‎(2)‎

• County: Fremont
• Community: Fremont County and Incorporated Areas
• Basin: Arkansas
• Title: FIS - Fremont County and Incorporated Areas
• Date: 9/19/2007
• Prepared For: Fremont County
• Prepared By: FEMA
• Floodplain - Doc Type: Current FEMA Regulatory Floodplain Information

Detailed information on floods before the turn of the century is very limited.
Information on past flooding is based on newspaper accounts and interviews with
long-time residents of the area.

Large floods have occurred in 1909, 1921, 1933, 1941, 1957, 1965 and 1974.
The flood of June 1921 is considered the most severe flood known in the area.
Peak discharges have been estimated by the United States Geological Survey
(USGS) at 2,760 cubic feet per second (cfs) for Oak Creek and 3,720 cfs for Coal
Creek. Floods in 1909 and 1932 were characterized by high-intensity
cloudbursts, while the floods in 1941, 1957, and 1965 were caused by high-
intensity cloudbursts coupled with hail-choked runoff channels.

2.4 Flood Protection Measures

In the 1930's, Coal Creek, in and around the City of Florence, was lined with
concrete slabs, grouted in place to form a concrete slope wall lining both sides of
the creek. The concrete lined portions of Coal Creek channel extend
southwesterly from immediately downstream of railroad Street Bridge to
immediately upstream of 5th Street in the north. A concrete floodwall (height
ranges from 1 to 3 feet above existing ground) was added at the banks of the
lined channel between Railroad Street and 5th Street. In accordance with FEMA
regulations, the analysis of the channel included modeling the floodwall in place
and breached. This channel through the City of Florence, however, is capable of
conveying only the minor flood volumes through the city without exceeding the
capacity of the channel and bridge structures over the channel.

Various agencies have performed minor channel clearing and installed riprap
along Coal and Oak Creeks, but no extensive flood control work has been
performed since the 1930's.

Dry Creek, a right bank tributary of Oak Creek, conveys floodwaters through the
City of Florence in a northerly direction. This stream, lying between Oak Creek
on the west, and Coal Creek on the east, enters the City of Florence at
approximately the Denver and Rio Grande Western Railroad and Frazier Avenue,
and enters the Oak Creek channel at approximately West Eighth Avenue, just
north of the City of Florence corporate limits. The Dry Creek Reservoir,
constructed in 1970 by the U.S. Department of Agriculture, Natural Resources
Conservation Service (NRCS), formerly the Soils Conservation Service (SCS)
has provided substantial relief from floods originating in the Dry Creek Basin.
The Dry Creek reservoir has 0.50 square mile of tributary drainage area. Prior to
construction of this reservoir, short duration, high intensity, summer
thunderstorms caused extensive damage to roads, schools, homes, and business
establishments in the City of Florence. The reservoir will contain the runoff from
a storm approximately five times the volume of a 10-percent-annual-chance
frequency storm. Peak flows from the local area below the reservoir will be
contained in the outlet channel and be through the basin by the time the
maximum peak flow, from the principal spillway occurs.

The City of Florence adopted a flood plain ordinance in December 1978 that
prohibited further development based on the Flood Hazard Boundary Map

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