How is “flood stage” determined on leveed rivers?
– April 2002 The National Weather Service (NWS) establishes flood stages on leveed rivers determined by industrial, navigational and recreational use. The definition of flood stage is that river level (height) at which damage begins to occur. In the Mississippi and the Atchafalaya basins, flood stages in some cases (Morgan City is a good example) are set at levels where navigation gets treacherous around bends. In others, like Red River Landing, the impact upon ferry crossings, river islands and farm land on the river side of the levee determines the flood stage. Baton Rouge, New Orleans and other metropolitan areas comprise another case in point. With the protection of the levee system, flood stages are set to reflect the threat to the river service industry and commercial use on the river side of the levee, not the threat to residential danger. In those cases, residential and commercial areas near the river are protected by the levee system to varying elevations much higher than the
