Skip Links

USGS - science for a changing world

Scientific Investigations Report 2014–5109

Prepared in cooperation with the Flood Control District of Maricopa County

Methods for Estimating Magnitude and Frequency of 1-, 3-, 7-, 15-, and 30-day flood-duration flows in Arizona

By Jeffrey R. Kennedy, Nicholas V. Paretti, and Andrea G. Veilleux

Thumbnail of and link to report PDF (11.4 MB)Abstract

Large floods have historically caused extensive damage in Arizona. Although peak-flow frequency estimates are required for managing the risk posed by floods, estimates of the frequency of sustained flood flow (flood-duration flow) are also useful for planning and assessing the adequacy of retention and conveyance structures and for water-resource planning. This report presents a flood-duration flow frequency analysis for selected durations (1 day, 3 day, 7 day, 15 day, and 30 day) at 173 streamgaging stations throughout Arizona and in western New Mexico. For each n-day duration, a log-Pearson type III distribution was fitted to the annual series of n-day flood-duration flows using the expected moments algorithm with a multiple Grubbs-Beck low-outlier test. Regional skews were developed independently for each n-day duration using a hybrid weighted least squares/generalized least squares method. No basin characteristics were found to adequately explain variation in skew among stations and a constant statewide skew model was used for all n-day durations. The regional skewness coefficient is negative for all n-day durations and becomes increasingly negative for longer n-day durations. Uncertainty associated with the skewness coefficient is estimated using a Bayesian generalized least squares technique.

Regression equations, which allow predictions of n-day flood-duration flows for selected annual exceedance probabilities at ungaged sites, were developed using generalized least-squares regression and flood-duration flow frequency estimates at 56 streamgaging stations within a single, relatively uniform physiographic region in the central part of Arizona, between the Colorado Plateau and Basin and Range Province, called the Transition Zone. Drainage area explained most of the variation in the n-day flood-duration annual exceedance probabilities, but mean annual precipitation and mean elevation were also significant variables in the regression models. Standard error of prediction for the regression equations varies from 28 to 53 percent and generally decreases with increasing n-day duration. Outside the Transition Zone there are insufficient streamgaging stations to develop regression equations, but flood-duration flow frequency estimates are presented at select streamgaging stations.

First posted December 9, 2014

Revised April 1, 2015

This publication is only available online

For additional information, contact:
Director, Arizona Water Science Center
U.S. Geological Survey
520 N. Park Avenue
Tucson, AZ 85719
http://az.water.usgs.gov/

Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Kennedy, J.R., Paretti, N.V., and Veilleux, A.G., 2015, Methods for estimating magnitude and frequency of 1-, 3-, 7-, 15-, and 30-day flood-duration flows in Arizona (ver. 1.1, April 2015): U.S. Geological Survey Scientific Investigations Report 2014–5109, 35 p., http://dx.doi.org/10.3133/sir20145109.

ISSN 2328-0328 (online)



Contents

Abstract

Introduction

Data Development

Regionalization

Summary and Conclusions

References

Figures (10)

Tables (10)


Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/sir/2014/5109/
Page Contact Information: Contact USGS
Page Last Modified: Tuesday, March 31, 2015, 04:10:01 PM