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Regression Equations for Estimating Flood Flows at Selected Recurrence Intervals for Ungaged Streams in Pennsylvania

U.S. Geological Survey Scientific Investigations Report 2008-5102

Prepared in cooperation with the Federal Emergency Management Agency, the Pennsylvania State Association of Township Supervisors, and the Susquehanna River Basin Commission

By Mark A. Roland and Marla H. Stuckey


View the report in Portable Document Format (PDF) SIR 2008-5102 (3.64 MB)


Abstract

Regression equations were developed for estimating flood flows at selected recurrence intervals for ungaged streams in Pennsylvania with drainage areas less than 2,000 square miles. These equations were developed utilizing peak-flow data from 322 streamflow-gaging stations within Pennsylvania and surrounding states. All stations used in the development of the equations had 10 or more years of record and included active and discontinued continuous-record as well as crest-stage partial-record stations. The state was divided into four regions, and regional regression equations were developed to estimate the 2-, 5-, 10-, 50-, 100-, and 500-year recurrence-interval flood flows. The equations were developed by means of a regression analysis that utilized basin characteristics and flow data associated with the stations.

Significant explanatory variables at the 95-percent confidence level for one or more regression equations included the following basin characteristics: drainage area; mean basin elevation; and the percentages of carbonate bedrock, urban area, and storage within a basin. The regression equations can be used to predict the magnitude of flood flows for specified recurrence intervals for most streams in the state; however, they are not valid for streams with drainage areas generally greater than 2,000 square miles or with substantial regulation, diversion, or mining activity within the basin. Estimates of flood-flow magnitude and frequency for streamflow-gaging stations substantially affected by upstream regulation are also presented.

Table of Contents

Abstract
Introduction
     Purpose and Scope
     Previous Studies
Development of Regression Equations
     Selection of Streamflow-Gaging Stations
     Basin Characteristics
     Regression Analysis
Flood-Flow Regression Equations
Limitations of Regression Equations
Summary
Acknowledgments
References Cited
Appendix 1. Streamflow-gaging stations and basin characteristics used in development of flood-flow regression equations for Pennsylvania streams
Appendix 2. Flood-flow magnitudes for selected recurrence intervals computed from observed streamflow-gaging data, predicted from regional regression equations, and a weighted average for streamflow-gaging stations used in analysis
Appendix 3. Flood-flow magnitudes for selected recurrence intervals for streamflow-gaging stations in Pennsylvania with drainage areas less than 2,000 square miles and streamflow substantially affected by upstream regulation


Suggested citation:
Roland, M.A., and Stuckey, M.H., 2008, Regression equations for estimating flood flows at selected recurrence intervals for ungaged streams in Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2008-5102, 57 p.


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View the report in Portable Document Format (PDF) SIR 2008-5102 (3.64 MB)


For more information about USGS activities in Pennsylvania contact:
Director
USGS Pennsylvania Water Science Center
215 Limekiln Road
New Cumberland, Pennsylvania 17070
Telephone: (717) 730-6960
Fax: (717) 730-6997
or access the USGS Water Resources of Pennsylvania home page at:
http://pa.water.usgs.gov/.

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