es·tu·ar·y

– noun
1. that part of the mouth or lower course of a river in which the river's current meets the sea's tide.
2. an arm or inlet of the sea at the lower end of a river.

lit·to·ral

– adj.
1. of or pertaining to the shore of a lake, sea, or ocean.
2. of or pertaining to the biogeographic region between the sublittoral zone and the high-water line and sometimes including the supralittoral zone above the high-water line.
3. of or pertaining to the region of freshwater lake beds from the sublittoral zone up to and including damp areas on shore.