The Alabama River is the heart river of the state. It is named for the Indian tribe of the same name who occupied the area at the confluence of the Coosa and Tallapoosa rivers where the Alabama first forms. The name Alabama comes from the Choctaw word “alba,” plants or weeds and “amo,” to cut or to trim meaning to clear the land or thicket clearers.
The Alabama River is formed by the confluence of the Coosa and Tallapoosa Rivers just 15 miles north of Montgomery. The mighty river begins at the Fall Line, an imaginary line demarcating the area of Alabama’s ancient coastline (See landuse maps under Land Use). Whereas the lower portions of Alabama’s major tributaries, the Coosa and Tallapoosa fell rapidly over dramatic falls and shoals, the Alabama basin lies almost entirely within the rather flat topography of the coastal plain.
After the Alabama is formed it flows approximately 15 miles before reaching the city of Montgomery. This 15-mile section is the steepest in slope, falling rapidly at approximately 5 feet per mile. At Montgomery the river takes on more of its Coastal Plain characteristics and transitions gradually to a slope of .82 foot per mile. Below the fall line the slope is approximately .34 foot per mile (Corps, ’98).
The river’s total length is 315 miles and drains 22,168 square miles in 18 counties.
After its birth the river meanders in a generally westerly direction for 100 miles to Selma and then Southwesterly 210 miles before it joins the Tombigbee River. These two large basins, the Alabama and Tombigbee merge to form the Mobile River near the city of Calvert and then flow into Mobile Bay and the Gulf of Mexico. The Alabama River watershed (excluding its largest tributaries the Coosa, Tallapoosa and Cahaba) comprises an area of 6,023 square miles.
The Alabama serves as the unifier of Alabama’s Eastern Rivers, the Coosa and Tallapoosa and her western rivers, the Cahaba, Black Warrior and Tombigbee. (Keith)
Physical features of the Alabama are striking and have been formed and reformed in both geologic and modern times. Free-flowing, or unimpounded sections of the river show many High Bluffs formed as the chalky soils of the Black Belt were carved away. In other areas, annual spring floods used to drive the Alabama miles inland, inundating farms with rich topsoil. Before the construction of the Alabama’s lock and dam system, low water during the summer and fall months exposed shoals and sandbars making the river all but impossible to navigate. Where the river joins the Tombigbee, swamps and marshlands are common.
Much of the true quality of the Alabama River has been altered by three Army Corps of Engineers dam projects constructed in the 60s and 70s to facilitate navigation. Of the Alabama’s 315 mainstem river miles, 233 are impounded by these Corps Dams. These impoundments are formed by the Robert F. Henry, Millers Ferry and Claiborne lock and dams (see Hydrologic Modifications).
Large tributaries of the Alabama include Little River, Limestone, Pursley, Turkey, Pine Barren, Cedar, Mulberry, Boguechitto, Big Swamp, Pintlala, and Catoma creeks (See Tributaries).
The Alabama River Basin generally experiences a mild, humid climate, with usually mild, short winters and long, warm summers. Rainfall is abundant and distributed fairly uniformly throughout the year. Floods resulting from general storms inundate bottomlands along the principal streams on an average of from two to five times a year. Floods along smaller streams resulting from intense local storms are more frequent. Though the majority of floods are confined to low-lying undeveloped areas, there is considerable rural and urban flood damage.
Montgomery and Lowndes Counties are two of Alabama’s dryest counties receiving an annual rainfall of less than 52 inches.
In terms of water quantity the Alabama River has a carrying capacity that varies from 100,000 to 150,000 cfs. (Corps ’98)
The mainstem of the Alabama River flows through or borders 9 Alabama counties: Elmore, Autauga, Montgomery, Lowndes, Dallas, Wilcox, Monroe, Baldwin and Clarke. At the southernmost tip of Clarke county the river joins the Tombigbee to form the Mobile River.