Headwater 2 : The water immediately upstream from a dam. The water surface elevation varies due to fluctuations in inflow and the amount of water passed through the dam.
National Dam Safety Program, U.S. Department of Homeland Security Federal Emergency Management Agency Interagency Committee on Dam Safety, Federal Guidelines For Dam Safety: Glossary of Terms For Dam Safety (FEMA-148), Washington DC, USA 2004. http://www.damsafety.org/media/Documents/PDF/fema- 148.pdf, (Dam Sfty - Amer) {890}