GENERALIZATION OF STREAMFLOW CHARACTERISTICS FROM DRAINAGE-BASIN CHARACTERISTICS by D.M. Thomas and M.A. Benson Prepared by the U.S. Geological Survey Water-Supply Paper 1975 TABLE OF CONTENTS Symbols Abstract Introduction     Acknowledgments Description of study regions     Eastern region     Central region     Southern region     Western region Selection of streamflow records for analysis Indices of streamflow characteristics     Low flows     Flow durations     Momentary flood peaks     Flood volumes     Mean flows     Standard deviations     Skew coefficients     Serial correlation coefficients Drainage-basin characteristics     Drainage area     Main-channel slope     Main-channel length     Surface storage     Elevation     Forested area     Soils index     Basin width     Alluvial area     Channel characteristics     Meander ratio     Bifurcation ratio     Mean flow distance     Valley width     Mean annual precipitation     Mean monthly precipitation     Snow     Precipitation intensity     Average annual evaporation     Thunderstorm days     Temperature Analytical methods Results Discussion of results     Variables effective in explaining streamflow variation     Accuracy of defined relations     Applicability of generalized relations to gaged sites     An accuracy test of Potomac River relations     Implications in design of data-collection systems Summary and conclusions References cited FIGURES 1. Map of conterminous United States showing locations of four study regions 2-5. Maps showing sites for which streamflow records were analyzed:     2. Potomac River basin     3. Central region     4. Southern region     5. Western region 6. Isohyetal map of mean annual precipitation in Soutern region 7. Isohyetal map of mean annual precipitation in Western region 8. Isohyetal and precipitation anomaly map of mean annual precipitation in Potomac River basin 9. Snow anomaly map of the Potomac River basin 10. Map of the Central region showing average annual snowfall 11. Graph showing relation of average water content of the April 1 snowpack to elevation for subregions of the Western region 12. Map of snowpack subregions for the Western region 13-16. Potomac River basin relations     14. Central region relations     15. Southern region relations     16. Western region relations TABLES 1. Ranges and averages of basin characteristics 2-5. Simple correlation coefficients for independent variables used in the     2. Potomac River basin analysis     3. Central region analysis     4. Southern region analysis     5. Western region analysis 6-9. Summary of regression relations     6. Eastern region     7. Central region     8. Southern region     9. Western region 10. Basin characteristics found to be signficantly related to streamflow 11. Observed and predicted streamflow characteristics for short-term streamflow record sites in the Potomac River basin ABSTRACT Definition of the natural streamflow in all streams, gaged or ungaged, is one of the principal objectives of the streamflow data-collection program of the Geological Survey. This report describes the results of using statistical multiple-regression analyses to provide a generalized definition of the natural streamflow in four widely separated regions of the eastern, central, southern, and western areas of the conterminous United States. In each study region, every long-term, virtually natural streamflow record was characterized by 71 or more flow indices. These indices represented magnitudes of high, low, and medium flows and also the distributions of flows in time. Numerous topographic and climatic indices were defined to describe the drainage basin above the site of each flow record. Multiple-regression analyses then defined the relation between each flow characteristic and the drainage-basin characteristics. The analyses also provided measures of the accuracy of each relation. Results of the regression analyses indicate that streamflow characteristics can be defined more accurately in the humid Eastern and Southern regions than in the more arid Western and Central regions, that medium flows can be more accurately defined than high flows, and that low flows can be only weakly defined. Standard deviations of monthy and annual flows were found to be significantly related to basin characteristics. Some indices of flow distributions in time (serial correlation and skew coefficients) could better be described by regional averages. Regression relations presented in this report may be used to estimate many natural-flow characteristics at any site in the study regions. In addition, the knowledge of basin characteristics found significantly related to streamflows and the knowledge of the accuracy of defined relations provide a firm technical basis for modifying and improving the existing streamflow data-collection system. LizardTech's Djvu plug-in is needed to view these reports. CLICK HERE TO VIEW THE ENTIRE REPORT For questions or comments, contact K. Van Wilson.