FLOOD00507

• Designation Number: 404
• County: Garfield
• County: Mesa
• Community: Unincorporated Mesa County
• Stream Name: Colorado River
• Title: Floodplain Information Report - Colorado River Mainstem, From Rifle to Utah-Colorado State line
• Date: 4/1/1996
• Designation Date: 5/1/1996
• Floodplain - Doc Type: Floodplain Report/Masterplan

The foon of the equation is the same for the 50-year frequency and the 100-year frcqucllcy; only
thc coefficients vary.

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Colorado River mainstem
Downstream of Rifle

for 50-year frequency: k=74.3, c= 0,706
for loo-year frequency: k"'71.28,c=O.772

3.3 Equation Selection Process

The CurveFit computer program analyzes thc input data using a library of 25 equations. The
output displays the constants and lhe correlaliofi values for each equation. The best fit equations
arc chosen based on the correJation value closest to 1.0. For lhis report an additiolllll stepv..<lS
included in the selection of an equation, Of all the possible equations which fell within a
correlation value greater than 0.95, the least complex equation was chosen. The same equation
foonat wasselectcd for both the SO-year and tOO-year flow calculations.

3.4 HvdrololZicFindinl!s

Table 3 sho'WS the results of this analysis in tabular foon. Figure 5 shows the relationship
between 50-year or loo-yearflow and drainage arca, as described by tbeseequation s,ingraphical
form.

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