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 2 at mile 87 (kilometer 140) above the mouth of the Red River call for a pool elevation of 58 feet (17.7 meters) and will cause an average increase in river stage of 12.5 feet (3.8 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 and will be near land surface in low areas. The potentiometric surface may be as much as 1 to 2 feet (0.3 to 0.6 meter) above land surface south of Latanier along Chatlin Lake Canal and south of the Annandale area of Alexandria. The magnitude of ground-water-level fluctuations near the river will be reduced.
