FLOOD04447

• County: Fremont
• Community: Florence
• Stream Name: Oak Creek
• Basin: Arkansas
• Title: City of Florence LMMP Study
• Date: 2/1/1993
• Prepared For: FEMA
• Prepared By: Love & Associates, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

HYDROLOGY FOR O.l\K CREEK

FLORENCE, COLORADO

DECEMBER 199J.

j?UHPOSE

The purpose of this study is to determine a peak discharge-
frEquency curve! for Oak Creek at Florence, Colorado. 'rhe values
will be utiliz,=d by the Federal EmergEOlncy Management: Agency for
prEparation of Flood Insurance Rate Maps. The results of this
study will also be utilized by the Corps of Engineers in a planning
study for Oak Creek. The discharge--frequency curve is shown on
Plate 5. This study was prepared undBr Planning Assistance to the
states authority, section 22 of Public Law 93-25J., at the request
of the Colorado Water Conservation Board. Another purpose of the
study is to det.=rmine the consequences, at Florence, of the failure
of a railroad embankment across South Oak Creek if it '.ere to act
as a dam during a flood. The railroad embankment is approximately
five miles upst:ream of Florence.

:I'm: WATERSHED

Oak Creek flows northeasterly c~t of the Wet Mountain range
until it joins the Arkansas River at Florence. Oak Creek has a
dr2inage area of 72 square miles and total length of 30.3 miles and
a weighted slope of 119 feet per mile. The average annua 1
prEcipitation at Florence is 12 inches of which 8 inches fall from
Hay to September. The average annual precipi 1:ation ranqes in the
watershed to almost forty inches in the headwaters, most of it in
thE: forn of snow. A map of the watershe!d is shown on plate 1.

The flood of 16 July 1923 was estimated by an engineering firm
to have a peak of 11,250 cfs (ref. 16), and the June 1921 flood was
estimated by the USGS to be 2,760 cfs (ref. 12).

jlEC-1 HODEL

UNIT HYDROGRAPH. A unit hydrograph was developed in ref. 12 for
the: Oak Creek watershed by the followinr,r equa1:ions:

qp-12, 650 (55t+0. DOl09) 1.08

1