The part of the dam that is in contact with the reservoir water. On Earthen Dams the upstream slope must be protected from the erosive action of waves by rock Rip Rap, concrete, or some other material.
UPSTREAM SLOPE (OF A DAM)
Meaning of UPSTREAM SLOPE (OF A DAM) in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012