FLOOD08379

• County: Statewide
• Community: State
• Stream Name: All
• Basin: Statewide
• Title: Procedures for Determining Peak Flows in Colorado
• Date: 3/1/1984
• Prepared For: State of Colorado
• Prepared By: USDA Soil Conservation Service
• Floodplain - Doc Type: Educational/Technical/Reference Information

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D. Construct the frequency line for the ungaged watershed (or any of
its subdivisions) by entering the plot with drainage area, finding
the magnitudes at each line of relationship, plotting the magnitudes
at their proper places on probability paper, and drawing the
frequency line through the points.

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In practice the method could be more complex but usually only in step C.
Other variables in addition to drainage area are related to the peaks or
volumes. These variables may include one or more of the following, alone or
in combinations, directly or by means of index numbers: type of climate,
mean annual precipitation or rainfall or snowfall, mean seasonal precipita-
tion or rainfall or snowfall, maximum or minimum average monthly rainfall,
storm pattern, storm direction and many others. For more complete list of
variables refer to SCS National Engineering Handbook, Section 4.

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The use of multiple regression methods is a necessity if more than one
variable appears in the relationship. Chapter 3, Book 4, Techniques of
Water Resources Investigations of U. S. Geological Survey is a basic
reference on regionalization.

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