Streamflow—Water year 2021

First posted August 19, 2022 For additional information, contact: U.S. Geological Survey 415 National Center Reston, Virginia 20192Contact Pubs Warehouse The maps and graphs in this summary describe national streamflow conditions for water year 2021 (a water year is the period from October 1 to September 30 and is designated by the year in which it ends; for example, water year 2021 was from October 1, 2020, to September 30, 2021) in the context of streamflow ranks relative to the 92-year period of water years 1930–2021. Annual runoff in the Nation’s rivers and streams during water year 2021 (9.43 inches) was higher than the long-term (1930–2021) mean annual runoff of 9.42 inches for the contiguous United States. Nationwide, the 2021 streamflow ranked the 46th highest out of the 92 years.