The U.S. Army Corps of Engineers (Corps) Albuquerque, Chicago, Detroit, Fort Worth, Galveston, Kansas City, Los Angeles, Omaha, Rock Island, Sacramento, San Francisco, St. Louis, St. Paul, and Tulsa Districts, and the U.S. Environmental Protection Agency (EPA), Regions 5, 6, 7, 8, and 9 jointly announce the availability of the Regional Streamflow Duration Assessment Methods (Regional SDAMs) for the Arid West, Western Mountains and Great Plains. The methods are rapid assessment tools for distinguishing between ephemeral, intermittent, and perennial streamflow at the reach scale for the Arid West, Western Mountains and Great Plains regions.