This volume is one of a series of 18 reports presenting measurements of stage, discharge, and content of streams, lakes, and reservoirs in the United States during the water year ending September 30, 1951. Since 1888, when the United States Geological Survey first studied streamflow in relation to problems of irrigation, similar measurements have been made at more than 12,400 gaging stations in the 48 States and at many others in the Territories of Alaska and Hawaii. On September 30, 1951, the Geological Survey and cooperating organization' were maintaining 6,730 gaging stations, including those in Alaska and Hawaii.
Miscellaneous discharge measurements were made at many other points in the 1951 water year.