The Mobile Bay Watershed encompasses 65% of the land area for the state of Alabama, along with portions of Mississippi, Georgia and Tennessee.  Mobile Bay is the terminus for the Mobile River, the Tombigbee-Black Warrior River, and the Alabama-Coosa-Tallapoossa River.   The watershed is a vast network of waterways, with more  than 250 separate waterways – rivers, bays, creeks, bayous, lakes, cutoffs, branches, and sloughs.

The outflow of the Mobile River into Mobile Bay creates a delta and extensive marshlands. The delta opens into the northern end of Mobile Bay through Mobile, Tensaw, Apalachee, Spanish and Blakley rivers. The Bay is approximately 32 miles long and 23 miles across at its widest point. The average depth in Mobile Bay is only about 10 feet, which makes it one of the most shallow for a bay of this size.  

Mobile Bay is Alabama’s central estuary system and provides a transitional zone, where the river’s freshwater meets tidally influenced marine waters. An estuary is a partially enclosed body of water formed where freshwater from rivers and streams flows into the ocean, mixing with the salty sea water. Estuaries are considered environmentally and economically important because of their exceptional biological diversity and productivity.

Area of Watershed: 115,467 Square Kilometers

Tributaries: Dog River, Fish River, Halls Mill Creek, Magnolia River, Mobile Bay, Polecat Creek, & Waterhole Branch

Major Habitat Types:  Submerged aquatic vegetation (seagrass), reefs (artificial), barrier islands/sand bars, lagoon/shallow open water shell fish growing areas, beach/due (bare & vegetated), sand/mud/salt flats, salt/brackish marsh, freshwater marsh (tidal & non-tidal), forested wetland, seasonal wetland, freshwater lakes/ponds, grass/open field, non-wetland forest, riparian/riverine (forested, tidal, & flood plain) abandoned, & agricultural

Species Diversity:
More than 800 species of non-vertebrates
337 species of fish (36 at risk)
126 amphibians & reptiles (30 at risk)
355 Birds (38 at risk)
49 mammals (7 at risk)

*Note: “at risk” not only includes Federal & State protection levels, but also non-regulatory listings by either researchers studying the species or by The Nature Conservancy’s Natural Heritage Program, which catalogues rare plant & animal species. (From Mobile Bay NEP)

Federally Endangered or Threatened Species:

• Mammals: Alabama beach Mouse, West Indian Manatee
• Birds: Bald Eagle, peregrine falcon, piping plover, red-cockaded woodpecker, wood stork
• Reptiles: Alabama red-bellied turtle, eastern indigo snake, gopher tortoise, loggerhead sea turtle
• Fish: Gulf sturgeon
• Insects: American burying beetle
• Plants: Alabama canebrake pitcher-plant, American chaffseed, Louisiana quillwort, Mohr’s, Barbara’s buttons