Maryland Department of Natural Resources

Power Plant Observation-Well Network

Groundwater is the principal source of freshwater supply in most of Southern Maryland and adjacent Eastern Shore. It is also the source of freshwater supply used in the operation of the Calvert Cliffs, Chalk Point, and Morgantown power plants. Increased groundwater withdrawals over the last several decades have caused groundwater levels to decline. The Maryland Geological Survey (MGS) and the U.S. Geological Survey (USGS) have maintained a groundwater level monitoring network started in the 1940s to observe changes in groundwater levels through time. Groundwater-level monitoring has been especially critical for Southern Maryland and adjacent Eastern Shore where groundwater is the primary source of water supply. Many observation wells were added to the network in the early 1970s following the establishment of the Power Plant Research Program (PPRP) of the Maryland Department of Natural Resources in order to monitor groundwater levels at Maryland power plants. Water-level data collected from the monitoring network and water-withdrawal data from the confined aquifers which supply water for the operation of Maryland’s power plants are used by the PPRP to evaluate potential impacts of Maryland’s power plants on groundwater resources.

Aquifers pumped by power plants in Maryland are as follows:

Calvert Cliffs: Aquia; Chalk Point: Magothy, Upper Patapsco, and Patuxent; Morgantown: Lower Patapsco; Panda: Lower Patapsco; Perryman: Surficial; SMECO: Upper Patapsco; and Vienna: Surficial

Potentiometric surface and difference maps are generated every two years and published by the U.S. Geological Survey for the confined aquifers (Aquia, Magothy, Upper and Lower Patapsco, and Patuxent)


2013 Potentiometric Surface Maps


Aquia aquifer

Aquia

Water levels in the Aquia aquifer ranged from 55 ft above sea level to 155 ft below sea level in 2013, and declined by as much as 113 ft between 1982 and 2013. Withdrawals from the Aquia aquifer have increased from approximately 5 Mgal/d in 1982 (Wheeler and Wilde, 1989) to approximately 16 Mgal/d in 2012.

Magothy aquifer

Magothy

Water levels in the Magothy aquifer ranged from 83 ft above sea level to 108 ft below sea level in 2013, and declined by as much as 81 ft between 1975 and 2013. Withdrawals from the Magothy aquifer increased from approximately 7 Mgal/d in 1975(Wheeler and Wilde, 1989) to approximately 8 Mgal/d in 2012.

Upper Patapsco aquifer

Upper Patapsco

Water levels in the Upper Patapsco aquifer system ranged from 115 ft above sea level to 110 ft below sea level in 2013, and declined by as much as 61 ft between 1990 and 2013.

Lower Patapsco aquifer

Lower Patapsco

Water levels in the Lower Patapsco aquifer system ranged from 105 ft above sea level to 199 ft below sea level in 2013, and declined by as much as 95 ft between 1990 and 2013. Total withdrawals from the Upper and Lower Patapsco aquifer systems increased from approximately 29 Mgal/d in 1990 to approximately 36 Mgal/d in 2012. Most of the withdrawals in 2012 were from the Lower Patapsco aquifer system (approximately 24 Mgal/d).

Patuxent aquifer

Patuxent

Water levels in the Patuxent aquifer system ranged from 165 ft above sea level to 109 ft below sea level. The withdrawal rates in the Patuxent aquifer system in the study area in 1990 and 2012 were approximately 23 and 22 Mgal/d, respectively.