estuary is a place where freshwater from a river mixes with saltwater
from the ocean. The estuary of the Altamaha River is in Glynn and
McIntosh Counties in southeastern Georgia and occupies an area of
about 45.25 square kilometers (km2).
quarters of that area is the mixing zone where fresh water flowing
from upland Georgia meets and mixes with salt water from the Atlantic
Ocean. The remaining parts of the estuary are the saltwater area
at the mouth of the river and the tidal freshwater area, at the
upstream end of the estuary, which is beyond the reach of salt water
but is affected by the same tides which mix the fresh and salt water
in the lower reaches of the river.
the tidal portion of the river, the water level rises and falls
twice a day in rhythm with ocean tides, and the flow of freshwater
slows as seawater is pushed into the mouth of the river.