ABSTRACT

Water use in Alabama was about 9,958 million gallons per day (Mgal/d) during 2005. Estimates of withdrawals by source indicate that total surface-water withdrawals were about 9,467 Mgal/d (95 percent of the total withdrawals) and the remaining 491 Mgal/d (5 percent) were from ground water. More surface water than ground water was withdrawn for all categories except aquaculture, mining, and self-supplied residential. During 2005, estimated withdrawals by category and in descending order were: thermoelectric power, 8,274 Mgal/d; public supply, 802 Mgal/d; self-supplied industrial, 550 Mgal/d; irrigation, 161 Mgal/d; aquaculture, 75 Mgal/d; self-supplied residential, 39 Mgal/d; livestock, 28 Mgal/d; and mining, 28 Mgal/d.

During 2005, about 83 percent of the water used in Alabama was for thermoelectric power to generate about 114,144 net gigawatt-hours of energy. Almost all of the thermoelectric-power water use (about 8,274 Mgal/d) was from surface water; nearly all of the water (98 percent) was used for once-through cooling, and most of that water was returned to a surface-water source.

Public-supply and self-supplied residential withdrawals were about 8 percent of total water withdrawals and about 50 percent of total water withdrawals for all categories excluding thermoelectric power. The combined public-supply and self-supplied residential ground-water withdrawals were about 64 percent of total ground-water withdrawals for Alabama. Public-supply deliveries to residential customers were 41 percent of total public-supply withdrawals, or about 326 Mgal/d; combined industrial and commercial deliveries were 44 percent, or about 355 Mgal/d; and public use and losses accounted for the remaining 15 percent, or about 120 Mgal/d.

Self-supplied industrial (550 Mgal/d) and mining (28 Mgal/d) withdrawals were about 6 percent of total water withdrawals and about 33 percent of total water withdrawals for all categories excluding thermoelectric power. Paper and allied products accounted for the largest self-supplied industrial surface-water withdrawals (301 Mgal/d), and chemical and allied products (12 Mgal/d) accounted for the largest ground-water withdrawals.

Water withdrawals for the agricultural sector—irrigation (161 Mgal/d), aquaculture (75 Mgal/d), and livestock (28 Mgal/d)—were about 3 percent of total withdrawals and about 16 percent of total withdrawals for all categories excluding thermoelectric power. About 135,800 acres of crops, nursery stock, sod, and golf courses were irrigated in 2005. About 97 percent of these acres were irrigated with sprinkler irrigation systems. The statewide average application rate was 1.33 acre-feet per acre per year. The highest application rate, 3.74 acre-feet per acre per year, was for nursery stock.

The largest total water withdrawals by county occurred in Limestone, Jackson, Colbert, and Mobile Counties, and were 60 percent of the total; these withdrawals primarily were used to meet the cooling needs at thermoelectric-power plants. Excluding thermoelectric power, the largest withdrawals by county were in Morgan, Mobile, Jefferson, Talladega, and Madison Counties.

Water use was estimated at the hydrologic subbasin level for all categories except aquaculture, mining, and self-supplied residential. The Middle Tennessee–Elk subregion accounted for about 53 percent (5,185 Mgal/d) of the estimated total withdrawals by subbasin of 9,816 Mgal/d. About 92 percent of the water use in the Middle Tennessee–Elk subregion was for thermoelectric power, and more than 99 percent of the water was from surface water.

Gross per capita use for all offstream uses was 2,185 gallons per day (gal/d) for the estimated 4.56 million Alabama residents in 2005. Public-supply per capita use was 199 gal/d for the estimated 4.04 million residents served by a public supplier; public-supplied residential per capita use was 81 gal/d. Self-supplied residential per capita use was 75 gal/d for the estimated 0.52 million self-supplied residential population. Average residential per capita use was 80 gal/d.

Total water withdrawals decreased less than 1 percent from 9,990 Mgal/d in 2000 to 9,958 Mgal/d in 2005. Surface-water withdrawals decreased less than 5 percent from 9,950 Mgal/d in 2000 to 9,467 Mgal/d in 2005. In contrast, ground-water withdrawals increased about 12 percent from 440 Mgal/d in 2000 to 491 Mgal/d in 2005. By category, increases in irrigation (118 Mgal/d, about 274 percent), thermoelectric power (84 Mgal/d, about 1 percent), and aquaculture (65 Mgal/d, 620 percent) were offset by declines in self-supplied industrial (283 Mgal/d, about 34 percent), self-supplied residential (40 Mgal/d, about 50 percent); and public supply (32 Mgal/d, about 4 percent) from 2000 to 2005. Water use for livestock and mining was not estimated in 2000.

First posted September 4, 2009