Weeks Bay is a micro-tidal sub estuary ofthe larger Mobile Bay System. A mean flow of nine cubicmeters per second of fresh water is brought into the estuary by two rivers,Fish River and Magnolia River, and their tributaries.
Salt water comes fromthe Gulf of Mexico through Mobile Bay.
Weak tidal currents in Mobile Bay andreduced summer winds allow the formation of a salt wedge between the densesalty water and the lighter fresh water. During the summer, salty water atthe bottom of Mobile Bay becomes hypoxic. At high tide, the salty wedge oflow oxygen water slides in through the deep mouth of Weeks Bay, relativelyundisturbed. In the winter and early spring stronger winds and storms causemore mixing of the fresh water and salty water in both Mobile Bay and WeeksBay. Plant species rimming Weeks Bay include salt marsh cordgrasses, blackneedlerush, and sawgrass followed in succession by wax myrtle, blueberries,wild Azalea, pond cypress and slash pines.