FLOOD00880

• County: Mesa
• Community: Rifle
• Stream Name: Colorado River
• Title: Floodplain Information Report - Colorado River Mainstem From Rifle to Utah-Colorado State line
• Date: 4/1/1996
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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

Colorado River mainstem
Downstream of Rifle

for 50-year frequency: k= 74.3, c= 0.706
for 100-year frequency: k= 71.28, c= 0.772

3.3 Equation Selection Process

The CurveFit computer program analyzes the input data using a library of 25 equations. The
output displays the constants and the correlation values for each equation. The best fit equations
are chosen based on the correlation value closest to 1.0. For this report an additional step was
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
format was selected for both the 50-year and IOO-year flow calculations.

3.4 Hydrologic Findings

Table 3 shows the results of this analysis in tabular form. Figure 5 shows the relationship
between 50-year or laO-year flow and drainage area, as described by these equations, in graphical
form.

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