In Alabama we take fresh water for granted. The state gets 55 inches of rain each year on the average, has over 77,000 miles of river and stream channels, and about 880 square miles of lakes.
However, periodic droughts cause problems. In 200, Lake Purdy, the main source of Birmingham's water, shrunk by 50% during the dry summer and water restrictions were imposed throughout Jefferson County.
How much water is used in Alabama? A lot. In 2000 it was about 2,200 gallons per capita per day, compared with the national average of about 1,200 gallons per capita per day. Obviously each of us doesn't use that much water, so who (or what) does?
Figure WR1. Alabama Fresh water consumption 2000.
What stands out (Figure WR1) is the huge percentage of water consumed by power generation, and most of it is used in coal-fired steam plants.
When compared with the nation as a whole, Alabama uses more of its water for power generation and significantly less in agriculture. The small amount of water used in agriculture shows how little irrigation is done in the state.
Although we use about 10 billion gallons of fresh water a day, most (92%) is non-consumptive use: the water is returned close to the point that it was extracted soon after being used. For example, the water used to generate electricity is predominantly non-consumptive use. Water that is removed, evaporated or held in crops is consumptive use.
The vast volume of our water is used, treated and released to be used again. Although this is good from a water quantity point-of-view, poor or no treatment of the used water can lead to pollution problems.
The Water Budget for Alabama
Figure WR2 shows an estimate of Alabama's water budget.
Figure WR2. Alabama's water budget.
As you can see rainfall is the major source of fresh water for the state.
Shortages of fresh water may occur if:
Annual Rainfall is highly variable, from a low of 34" in 1954 to a high of 76" in 1975 (Figure WR3).
Figure WR3. Average Rainfall for Alabama 1904-2004.
A 5" drop below average (55") causes a decrease of 12 bgd of fresh water in the system. In the last 100 years, Alabama has 27 years with less than 50"of rain.
The headwaters of the Coosa and Tallapoosa rivers are in northern Georgia, and water is taken from both rivers (primarily for Atlanta) before they enter Alabama (Figure RL1).
In 1990, Georgia asked permission from the Army Corps of Engineers to build new reservoirs on the Chattahoochee River, the Flint River, and the Coosa River so that it could retain an additional 529 million gallons of water a day. The water was to be stored in Lake Sidney Lanier. Alabama sued to stop the plan, and Florida joined the suit. In the USA, each state controls the use of water within its boundaries, and in the eastern part of the nation is subject to the riparian rights doctrine. That doctrine states that a land owner bordering a natural watercourse has rights to reasonable use of water, as long as that use does not reduce the quality or accessibility of the water to other users bordering the watercourse (Figure WR4). As of 2006, the argument continues.
Figure WR4. Although the western bank of the Chattahoochee River is the Georgia-Alabama border, under riparian water rights landholders along the banks in Alabama also have rights to its water. (Image © Mike Neilson)