The National Technical Committee for Ordinary High Watermarks (OHWM), made up of researchers from the U.S. Army Engineer Research and Development Center’s (ERDC) Cold Regions Research and Engineering Laboratory (CRREL), the Environmental Protection Agency, regulators from the U.S. Army Corps of Engineers and other academic institutions, stand in front of a waterfall following a field test of an interim OHWM identification data sheet. The data sheet is part of a recently released National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams, which has been in development for 10 years.