FLOOD05613

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Rainfall-Runoff Data from Small Watersheds in Colorado June 1968 - September 1971
• Date: 1/1/1972
• Prepared For: State of Colorado
• Prepared By: CWCB
• Floodplain - Doc Type: Data ‎(general)‎

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RAINFALL-RUNOFF DATA FROM SMALL WATERSHEDS IN COLORADO,
JUNE 1968 THROUGH SEPTEMBER 1971

By G. Louis Ducret, Jr. and Harold E. Hodges

INTRODUCTION

The magnitude and frequency of peak discharges must be considered
in the design of storm-drainage syscems or structures. Regional
flood-frequency analyses, which provide the means for eatimating the
mean annual flood and floods of other frequencies at any desired
location, have been made for relatively large watersheds in Colorado
by Matthai (1968), Patterson (1964, 1965), and Patterson and
Somers (1966). However, this information does not generally apply to
small basins or to basins that are altered by urban development.
Design estimates in these areas based on extrapolations of regional
flood-frequency data are likely to be substantially in error. For
this reason the U.S. Geological Survey, in cooperation with the
Urban Drainage and Flood Control District and the Colorado Department
of Highways, is conducting studies in which rainfall-runoff data from
small watersheds are being collected and analyzed for the purpose of
defining the flood characteristics of these areas.

For the data collection phase of the project, a gage network was
designed to provide continuous records of rainfall and runoff from
small watersheds. This network, consisting of 73 stations, is now in
operation throughout Colorado with the following distribution:

1. Thirty urban stations in the Denver metropolitan area (fig. 1)
sample basins that range in size from about 40 acres to about 1.5 square
miles and include a broad spectrum of other basin_characteristics such
as extent of urban development. A listing of urban stations is provided
in table 1.

2. Forty-three highway stations in eastern and southwestern
Colorado (fig. 2) in basins that range in size from about 1 to about
25 square miles and include a broad spectrum of basin characteristics
in a rural environment. A listing of highway stations is provided
in table 2.

Stations were installed by phases beginning in June 1968 and
continuing until May 1971 on the following schedule: Five stations
operational by June 1968, 27 by July 1969, 51 by May 1970, and 73 by
May 1971. All stations operate only during the anticipated storm
runoff season from about mid-April through September.

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