Groundwater level measurements of 516 wells that tap the alluvial aquifer in the Quaternary deposits of the Mississippi Alluvial Plain were made by U.S. Geological Survey and district Soil Conservation Service personnel during 1987. The shallowest prepumping water levels occurred in Ashley, Clay, Crittenden, Greene, Mississippi, Phillips, and Randolph Counties where water levels averaged less than 20 ft below the land surface. The deepest water levels occurred in Arkansas, Lonoke, Poinsett, and Prairie Counties where water levels of more than 100 ft below land surface were measured. Water levels in the postpumping season averaged about 3.3 ft lower than during the prepumping season. (USGS)