U.S.
GEOLOGICAL SURVEY
Water-Resources Investigations Report 99-4248
Computed Roughness Coefficients for Skunk Creek above Interstate 17, Maricopa County, Arizona
By
C.M. O'Day and J.V. Phillips
ABSTRACT
In the winter of 1997-98, the U.S. Geological Survey, in
cooperation with the Flood Control District of Maricopa
County, made six verification measurements for Manning's
roughness coefficients at Skunk Creek above Interstate 17.
Data from four floodflows were recorded and analyzed,
three of these flows occurred in February 1998 when
Arizona received precipitation from the El Nino weather
phenomenon. Discharges ranged from 187 to 760 cubic
feet per second and resultant verified values for Manning's
roughness coefficient, n, ranged from 0.056 to 0.039.
Skunk Creek above Interstate 17 - an ephemeral wash
within a flood-control structure - is overgrown with desert
brush throughout the main channel and the presence of the
vegetation has a significant effect on n values throughout
the reach. The results of this study are verified roughness
coefficients that can be transferred to similarly vegetated
channels in Maricopa County and other arid and semiarid
environments where roughness factors must be assessed
for flood management or other purposes.
Abstract
Introduction
Background
Purpose and scope
Description of study area
Data collection and analysis
Computed roughness coefficients
Summary
Selected references
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