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U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 03-4180

Estimating the Magnitude of Peak Flows for Streams in Kentucky for Selected Recurrence Intervals


By Glenn A. Hodgkins and Gary R. Martin

The report is available in PDF format.


Abstract

This report gives estimates of, and presents techniques for estimating, the magnitude of peak flows for streams in Kentucky for recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years. A flowchart in this report guides the user to the appropriate estimates and (or) estimating techniques for a site on a specific stream.

Estimates of peak flows are given for 222 U.S. Geological Survey streamflow-gaging stations in Kentucky. In the development of the peak-flow estimates at gaging stations, a new generalized skew coefficient was calculated for the State. This single statewide value of 0.011 (with a standard error of prediction of 0.520) is more appropriate for Kentucky than the national skew isoline map in Bulletin 17B of the Interagency Advisory Committee on Water Data.

Regression equations are presented for estimating the peak flows on ungaged, unregulated streams in rural drainage basins. The equations were developed by use of generalized-least-squares regression procedures at 187 U.S. Geological Survey gaging stations in Kentucky and 51 stations in surrounding States. Kentucky was divided into seven flood regions. Total drainage area is used in the final regression equations as the sole explanatory variable, except in Regions 1 and 4 where main-channel slope also was used. The smallest average standard errors of prediction were in Region 3 (from -13.1 to +15.0 percent) and the largest average standard errors of prediction were in Region 5 (from -37.6 to +60.3 percent).

One section of this report describes techniques for estimating peak flows for ungaged sites on gaged, unregulated streams in rural drainage basins. Another section references two previous U.S. Geological Survey reports for peak-flow estimates on ungaged, unregulated, urban streams. Estimating peak flows at ungaged sites on regulated streams is beyond the scope of this report, because peak flows on regulated streams are dependent upon variable human activities.


TABLE OF CONTENTS

Sections available in pdf:

Cover Page

Section-1  7.4MB

Abstract
Introduction
Description of study area
    Climate
    Physiography and geology
    Seasonality of peak flows
Data used for peak-flow estimates and estimating techniques
Development of peak-flow estimates and estimating techniques
    Peak flows at gaging stations
        Detailed Bulletin 17B analyses
        Generalized skew for Kentucky
    Peak flows at ungaged locations
        Defining flood regions
        Choosing explanatory variables
        Determining final regression coefficients

Section-2 243KB

    Weighting gaging-station peak-flow estimates with regression-equation peak-flow estimates
Estimating the magnitude of peak flows for selected recurrence intervals
    Choosing the appropriate peak-flow estimation technique
    Estimates of peak flows at U.S. Geological Survey streamflow-gaging stations
        Presentation of the estimates
        Limitations and accuracy of the estimates
    Estimating peak flows for ungaged sites on regulated streams or streams with diversions
    Estimating peak flows for ungaged, unregulated streams in urbanized drainage basins
    Estimating peak flows for ungaged sites on gaged, unregulated streams in rural drainage basins
        Application of the technique
        Limitations of the technique
    Estimating peak flows for ungaged, unregulated streams in rural drainage basins
        Application of the technique
        Limitations and accuracy of the technique
    Example applications of the estimating equations

Section-3  2.9MB

Summary
References cited


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Send questions or comments about this report to GS-W-KYlsv_INFO@usgs.gov

For more information about USGS activities in Kentucky, visit the USGS Kentucky District home page.




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