FLOOD05435

• County: Elbert
• Community: Elizabeth
• Stream Name: Running Creek
• Basin: South Platte
• Title: Floodplain Information Report
• Date: 7/1/1979
• Prepared For: Elizabeth
• Prepared By: WRC Engineering, Inc.
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

b,'8i~s. Flood ~eco~ds f~OflI gages <>n the"" streams p~ovide the "'ajority or
data fo~ this region.

in the region. The Running Creek flood predictions src ~eason.ble based on
this comparison and the flood history of Running Creek.

Flood data for the region is statistically analyzcd to obtain a curve
relating the mean snnual peak flood to the drainage area size. The desired
10- and 100-yesr frequency floods are computed using a set of ratios of
var.ous flood frequencies to the mean annual peak flood.

After review of the strengths and weaknesses of each procedure, the
de.ign hydrology WaS selected utilizing the ~esults from the four methods.
The detailed computations fo~ the different methods were submitted to the
Colorado Water Conservation Board aa part of the technical addendum. The
selected peak flows in Running Creek at specified design points for the 10-
and 100-year frequency flood are presented in Table-4 below.

2. Technical Manual No.1 - The Colorado Water Conservation Board in
,
cooperation with the U.S. Geological Survey and others, has developed a manu-
al for "stimating flood charact"ristica of Colorado streatl~. The ..anua!
provides a simplified m~thod for calculating floods in the Eastern Plains
arca based on drainage basin geomet~y. Regreaaion cquationa are derived which
~elate basin slope snd drainage area to p~ak flow.. The equations were devel-
oped by relating flood characteristics at gaged sitea to basin and climatic
parameters. The least sensitive parameters were eliminated in the final
reg~es.ion equation..

TAflLE4
RUNN"INC CREEK-PEAl< DISCIlARGES

LOCATION

REFERENCE *
LINE STATION

DRAINAGE AREA
(Square Miles)

Qw
(cia)

Q100
(cia)

3. Soil Conservation Service National EnKineerin~ Handbook ~ The Soil
Conservotion Service has developed a widely accepted proccdu~c for predicting
floodflows u.ing ~ainfall data and ba..n parame~e~s. Rainfall is applied to
the b.;o;i" ...,,,1 th~ ,.,,~....lti,,~ ~un<.>ff .i~ co",puled ha.ed "" s"il iLl[iln"t;i"",
v"!Ie~.tion and terrain characteristics. This II1i'.thod produce. a complete storro
hydrograph for the basin.

Upstr..a" Stody Limit 77"00 50.2 5,000 12,600
TribcltaryConflucncc 62"00 51.8 5,080 12,790
State Ilighw,qy 86 B~idg" 2R+OO 53.0 5,130 12,930
Downstream Study Limit 1"00 54.0 5,180 1),050

* See flooded Area Plate. (paze. 28 throog~ 31).

4. Soil Conservation Se~vice . "Peak Flows in Colorado" - The Soil Con-
"~rva~ion Scrvice has aho pclblished a method spccifically lor determining
peak flows in Colorado. The procedure is simil.r to that de.crihed ill M~thod
3 nbove, but it simplific. the 3pplication of rainfall data and do~s oot pro-
~idQ thc co"'pletc hyd~ograph.

The flood predictions from each of thea,. f<Jur method. w"~,, ~lso ~omrnred
..itb dULa ['.001 "the' [1o"ul'l"i" infomaliol\ <eporls and with historical flood,

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