U.S. Department of the Interior U.S. Geological Survey TECHNIQUES FOR ESTIMATING MAGNITUDE AND FREQUENCY OF PEAK FLOWS FOR PENNSYLVANIA STREAMS by Marla H. Stuckey and Lloyd A. Reed Water-Resources Investigations Report 00-4189 prepared in cooperation with PENNSYLVANIA DEPARTMENT OF TRANSPORTATION Lemoyne, Pennsylvania 2000 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director The use of product names in this report is for identification purposes only and does not constitute endorsement by the U.S. Government. For additional information Copies of this report may be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services 840 Market Street Box 25286 Lemoyne, Pennsylvania 17043-1586 Denver, Colorado 80225-0286 Email:
[email protected] Telephone: 1-888-ASK-USGS ii CONTENTS Page Abstract . .1 Introduction . .1 Purpose and scope. .2 Previous investigations. .2 Development of flood-frequency prediction equations . .2 Description of stations used. .2 Basin characteristics used in equation development . .4 Regression analysis and resultant equations. .7 Limitations of regression equations . .12 Techniques for estimating magnitude and frequency of peak flows . .15 Summary and conclusions . .19 References cited . .19 Appendix 1. Basin characteristics for streamflow-gaging stations used in the development of the regional regression equations . .22 Appendix 2. Flood-flow frequencies computed from streamflow-gaging data and regression equations for streamflow-gaging stations used in analysis . .33 ILLUSTRATIONS Figures 1-3. Maps showing: 1. Streamflow-gaging stations used in development of flood-flow regression equations for Pennsylvania streams . 3 2. Carbonate regions in Pennsylvania.