Streamflow—Water year 2021

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.