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of ungaged streams. The most effective method of regionalization presently known, and the one which should lead most rapidly to the general definition of streamflow characteristics, is the multiple-regression method. It defines streamflow in terms of the environment; that Is, In terms of the basin characteristics and climatic characteristics that cause variation In streamflow from one place to another (Benson, 1962; Benson, 1964j James, 1968). The regression equation used has the form Y = a Ab SC pd where Y is a streamflow characteristic and A, S, P, etc., are basin or climatic characteristics. The constants a, b, c, etc., are determined by a standard statistical procedure, using data from stations at which the streamflow characteristics are well defined. Once the equation and its constants are defined, streamflow charac- teristics for a specific site in a given basin can be approximated by sub- stituting the appropriate values of the hydrologic variables in the formulas. Following the multiple-regression analyses of James (1968), who used data from 41 complete-record gaging stations in and near Kansas, new analyses were made using data from 34 additional complete-record stations covering a wider range of physical and cl,imatic characteristics. The gag- ing stations used in the analyses and the values of the physical and cli- matic characteristics are listed in table 4. The physical characteristics are defined and were determined as follows: Drainage area (A), in square miles, is the total drainage area upstream from the,gaging-statlon site and Is that shown In the latest published U.S. Geological Survey reports. Contributing drainage area (Ac) , in square miles, is the area contri- buting directly to surface runoff. I Alluvial area (Aa) , In square mIles, Is the alluvium shown on State geologic maps at a:scale total area of valley of 1:500,000. Main channel slope (Sl), in feet per mile, between points 10 percent and 85 percent of the site to the basin divide (main channel length). was computed as the difference in elevation, In percent points divided by the length, in miles, using the best available topographic maps. Main channel length (Ll, In mi les, Is the length of the main channel between the gaging station and the basin divide measured along the channel which drains the largest basin, using the best available maps. is the average slope distance from the gaging The main channel slope feet, at the 10 and 85 between the two points, 22