DETAILED HYDROGEOLOGIC STUDIES OF THE BATON ROUGE AQUIFER SYSTEM NORTH OF BATON ROUGE, LOUISIANA

The Baton Rouge aquifer system is located in the Gulf Coast Plain and occurs as an en echelon series of sediments that dip southward and outcrop to the north in northeastern Louisiana and southern Mississippi. The aquifer system is somewhat unique in the Gulf Coast because the east-west trending Baton Rouge fault partially controls northward saltwater movement in the aquifer system limiting saltwater movement toward pumping centers. The aquifer system contains water of generally very high quality and the outcrop areas receive an average of from 54 to 60 inches of rainfall annually.

The aquifer system includes eleven major aquifers ranging in geologic age from Pleistocene to basal Miocene. Recent detailed hydrogeologic studies north of Baton Rouge have mapped the outcrops, potentiometric surfaces, and zones of hydraulic conductivity for the ten upper-most aquifers. Groundwater simulations based on these parameters provided an estimate of rates of groundwater flow in each aquifer, however, the simulations were two dimensional therefore leakage between the aquifers could not be calculated and flow budgets have reduced accuracy.

In the aquifer system the “400-“, “600- “, “800-“, and “1,000-foot” sands outcrop in Louisiana; the “1,200-“, “1,500-“, “1,700-“, “2,000-, “2,400-“, and “2,800-foot” sands outcrop in Wilkinson County, Mississippi. The Catahoula is the deepest aquifer in the system and it outcrops farther north in Mississippi beyond the study area. The time-of-travel from outcrops in Louisiana to near the City of Baton Rouge was estimated to range from about 250 to 2500 years, and related flow rates from outcrops in the State of Mississippi typically ranged from 2500 to 3500 years.

Comparisons of hydrographs from all of the aquifers indicate that Baton Rouge pumping has greatly impacted and lowered water levels throughout the entire aquifer system.