The director of the Maryland Geological Survey reported to St. Mary's County officials this week on the results of a multi-year study showing declining groundwater levels across Southern Maryland.

The study involved data from six exploratory wells drilled into the region's aquifers. It used population projections and computer modeling to estimate water use out to 2030.

"You're not facing an immediate problem," Emery T. Cleaves, director of the Maryland Geological Survey, told the county commissioners. "You're facing some concerns, but you don't have a crisis."

The preliminary report from the study shows groundwater has dropped under several population centers. The Aquia aquifer under Leonardtown has dropped from about 20 feet below sea level in the late 1970s to about 80 feet below sea level now; under Lexington Park, the aquifer is down to about 180 feet below sea level, hydrogeologist David Drummond said.

Even with these drops, by 2030 St. Mary's is not expected to reach what is known as the "management level" -- at which 80 percent of the pressure in the aquifer has been lost. At that point, the state Department of the Environment would prohibit further extraction, the hydrology officials said.

Several consequences of declining water levels, include higher costs for drilling deeper wells, a possibility of contaminating the freshwater with brackish water, reducing the level of some streams and altering the ecology of some wetlands, Drummond said.

In the past half-century, the amount of water pumped from Southern Maryland wells roughly tripled, to 43.4 million gallons per day.