Proposed construction of a series of locks and dams in the Red River in Louisiana will cause a permanent increase in average river stage. The potentiometric surface of the shallow alluvial aquifer and the water table in the fine-grained material confining the aquifer will be affected. The purpose of this study, using digital-modeling techniques, was to predict the average postconstruction potentiometric surface (steady state) and the water table (nonsteady state) so that potential effects of the water-level changes could be evaluated.
Plans for Lock and Dam 1 at mile 44 (kilometer 71) above the mouth of the Red River call for a pool elevation of 40 feet (12.2 meters) and will cause an average increase in river stage of 9 feet (2.7 meters). As a result, ground-water levels will be raised 1 foot (0.3 meter) or more within 4 miles (6.4 kilometers) of the river. The potentiometric surface may be near land surface in low-lying areas, and above land surface along the course of drainage features near the dam. The magnitude of ground-water-level fluctuations near the river will be reduced.