gate of staumauer bitburger dam with water flowing out into prum river

barrier bitburg bitburger bridge brown canal cascade concept contamination control dam day dike downstream dyke ecology energy engineering environment europe flood floodgate flow flowing gate gateway germany hydraulic hydro infrastructure lake levees lock nature outdoor overflow passage pollution power prum reservoir rill river sluice spillway spots spring staumauer stausee stream sunny surface system technology wall water watercourse waterfall watergate waterway weir