Potentiometric surface of the Wilcox-Carrizo aquifer; Bienville, Red River, and northern Natchitoches, and southern Webster Parishes, Louisiana

The potentiometric surface of the Wilcox-Carrizo aquifer in central northwestern Louisiana is shown by contours using data collected from 1960 to 1980. The aquifer is not affected by regional water-level declines as no large pumping centers have been developed. Seasonal water-level fluctuations in wells are generally less than 10 feet annually.