Streamflow—Water year 2018

The maps and graphs in this summary describe national streamflow conditions for water year 2018 (October 1, 2017, to September 30, 2018) in the context of streamflow ranks relative to the 89-year period of water years 1930–2018. The illustrations are based on observed data from the U.S. Geological Survey National Streamflow Network. Annual runoff in the Nation’s rivers and streams during water year 2018 was higher than the long-term (water years 1930–2018) mean annual runoff of 9.33 inches. Nationwide, the 2018 streamflow ranked 33d highest out of the 89 years.