Large quantities of ground water and surface water are available in Choctaw County. Major sources of ground water are the Nanafalia Formation, Tuscahoma Sand, Hatchetigbee Formation, and Gosport Sand and Lisbon Formation. The Nanafalia Formation is the most productive source of ground water, and individual wells will yield as much as 1.0 mgd (million gallons per day). The depths to aquifers and the quality of ground water in the south half of the county are governed in part by geologic structures.
The average flow of the Tombigbee River at the southeast corner of the county is 16,500 mgd and the 7-day Q2 exceeds 1,000 mgd. Kinterbish, Tuckabum, and Okatuppa Creeks have average flows that range from 115 to 265 mgd at their confluences with the Tombigbee River and 7-day Q2's that exceed 10 mgd in their downstream reaches. Average runoff originating in the county is about 786 mgd or 0.8 mgd per square mile.
Water in aquifers tapped by wells generally contains less than 500 mg/1 (milligrams per liter) dissolved solids and is soft to moderately hard. In southeastern parts of the county, in the vicinity of the Hatchetigbee anticline, wells have been abandoned because of the poor quality of water.
Water in streams, with the exception of that in Okatuppa Creek and some of its tributaries near Gilbertown and Barrytown, is generally soft and contains less than 140 mg/1 dissolved solids. The quality of water in Okatuppa Creek and some of its tributaries reflects contamination by oil-field brines. Biweekly samples collected from Okatuppa Creek from September 1965 to May 1967 show an average chloride content of 312 mg/1 and specific conductances indicate an average dissolved solids content of 630 mg/ 1.
