Yearly variations in runoff and frequency of dry years for the conterminous United States, 1911-79

Gaging-station data are presented on variations in annual runoff over the conterminous United States and nearby Canada during the period 1911-79 in tabular and graphic (map) form. These data bring up-to-date and extend backward in time previous reports on streamflow stations by Harbeck and Langbein in 1949 which covered the period 1921-45 and that by Busby in 1963 which covered the period 1931-60. As depicted in Langbein and Slack (1980), these data show that, contained within a rather large seemingly random or sporadic pattern, there appears to be a previously unnoticed degree of similarity in the occurrence of subnormal flows across the country. In each of three regions, viz., West, Center, and East, dry years were concentrated in two sequences, one centered in the 1930 's and the second in the decade from the mid-50 's to the mid-60's. (USGS)