FN: a (usually unspecified) height. In this very flat area the water level rises about 2 m during floods , suggesting a minimum subsidence of 4 m over about 70 years .The distance will undoubtedly depend on local conditions and the original slope of the valley floor , but this exercise supports Saucier 's ( 1991 ) contention that Pleistocene sea level change in the lower Mississippi valley was effective only as far as Baton Rouge ( see also Blum , 1993 and Blum and Valastro , 1994 ) .Although the multi-paned windows are present at an upper level of the wall , the corner of the room is glazed with large , mullionless sheets of plate glass , offering dramatic views of Long Island Sound .Sightseeing in Hong Kong starts at sea level with the enthralling water traffic — a mix of freighters , ferries , tugs , junks , and yachts .A tectonic interpretation is favored because a local rise of base level can not be involved .Indeed , Lane 's ( 1955 ) argument that a stream will restore its gradient at a higher or lower level following a baselevel change is conceptually correct because if the river is initially at grade , then to move its sediment load and water discharge through the channel , the original gradient of the stream must be reestablished .