FLOOD08910

• County: Elbert
• Community: Elbert County
• Stream Name: Kiowa Creek
• Basin: South Platte
• Title: Floodplain Information Report
• Date: 1/1/1976
• Prepared For: Elbert County
• Prepared By: United Western Engineers
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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III. Future Floods

A. DESCRIPTION AND METHOD,

As required, the flood used for analysis in this study is one
which would occur on an average of once each 100 years, or which might
have a probability of occurance of one percent in any given year. This
is referred to as the "100 year flood."

Two primary methods of investigation were made. The first of
these is the USDA-SCS synthetic hydro graph method as described by their
references in a later section. The second is a method based on historic
records of the region as analyzed by the US Geological Survey. A com-
plicating factor is the 37 flood control reservoirs installed by the SCS
above Elbert.which control the runoff of60 percent of the basin area.

The effects of these flood control measures were carefully analyzed
on five typical structures for which complete data was available. The
results show that these structures provide significant benefit on floods
of a relatively small magnitude. However, on the 100 year flood their
benefit is not as grea,t as might be anticipated, although there is not
felt to be any danger of the failure of these structures which would
create a hazard downstream.

A substantial amount of technical information was processed in
this studj, and will not be ,presented in detail herein. The following is
a summary of the 100 year design runoff at Elbert.

TABLE 4 - Projected 100 Year Runoff At Elbert.

DRAINAGE DRAINAGE AREA 100 YEAR STORM RUNOFF
Square Miles Cubic Feet Per Second
West Kiowa Creek 35.99 13,400
East Kiowa Creek 28.78 10,900
Kiowa Creele at Elbert 64.77 17,300

It may be noticed that these runoffs are well below those recorded
in 1965 and computed in 1935. Having two such storms in the previous 40
years would cast some logical doubt on the accuracy of such a projection
for a 100 year storm. A regional analysis - considering the entire area -
puts this into persptective, and it can be said again that Kiowa Creele
has received far more than its fair share of substantial rainfall.

B. Flood Plain Description

The limits of the flood plain are shown on the three sheets of
plate 2 in the appendix. The creele was divided by numerous "cross-sections"
at critical locations along its length., The floodwaters are generally

.,"

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