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 5 at mile 243 (kilometer 390) above the mouth of the Red River call for a pool elevation of 145 feet (44 meters) and will cause an average increase in river stage of 23 feet (7.0 meters). As a result, ground-water levels in the pool area will be raised to near land surface in much of the area between the river and Bayou Pierre and as much as 2 miles (3.2 kilometers) east of the river from the dam upstream to realined mile 220 (kilometer 350). Areas of Barksdale Air Force Base where levels are now near land surface would be enlarged and extend downstream along Flat River to near Curtis. The potentiometric surface may be above land surface near Howard, Anderson Island, and Dixie Gardens. (Woodard-USGS)