Maryland Department of Natural Resources

Anne Arundel County Observation-Well Network

The Anne Arundel County water-level network is one of five observation-well networks maintained by MGS and funded through cooperative agreements with Anne Arundel, Calvert, Charles, Queen Anne’s, and St. Mary’s counties.

Location of network observation wells

The primary objective of these networks is to monitor the effects of water-supply withdrawals on groundwater levels at both a local (well field) and regional scale. More specifically the water-level data are used to help assess (1) long-term sustainability of the water supply; (2) well interference (drawdown at each well in a multiple-well system added to drawdowns at the other wells); (3) potential for increased development of the aquifers; (4) potential for salt-water intrusion, where applicable; and (5) the role of ground-water extraction in land subsidence.

The Anne Arundel County observation-well network, initiated in the late 1980's, is currently funded through a cooperative agreement between Maryland Geological Survey and Anne Arundel County Department of Public Works. The network consists of 42 wells located mainly in the central and northern part of the County. Aquifers monitored include the Patuxent (7 wells), Lower Patapsco (19 wells), Upper Patapsco (8 wells), Magothy (7 wells), and Aquia (1 well). Frequency of measurement ranges from 6 times a year to semiannual (spring and fall).



Current Water-Level Trends


hydrograph for observation well AA Fe 92 in the Aquia aquifer

Aquia aquifer


Since monitoring began in 2000, water levels in the Aquia aquifer in Southern Anne Arundel County at the Deale Athletic Field (AA Fe 92) have declined from about 24 ft in 2004 to about 34 ft below sea level in 2016. While fluctuating by as much as 8 ft as a result of local pumpage, the overall water-level trend since about 2006 has been relatively flat. The flattening of the trend is largely a result of a reduction of withdrawals from the Aquia aquifer in St. Mary’s County as pumpage was shifted to the deeper Upper Patapsco aquifer to avoid elevated arsenic concentrations in the Aquia.

hydrograph for observation well AA Df 79 in the Magothy aquifer

Magothy aquifer


The most recent water levels in the Magothy aquifer range from about three feet above sea level west of Annapolis (AA Dd 42) to about 36 ft below sea level at the Annapolis well field (AA De 1); although water levels in AA De 1 are affected significantly by a nearby production in that well field. Most water levels show some stabilization since 2008 with the exception of AA Fe 93 in Southern Anne Arundel County which continues to decline.

hydrograph for observation well AA Cg 24 in the Upper Patapsco aquifer

Upper Patapsco aquifer


The most recent water levels in the Upper Patapsco aquifer range from about 73 ft above sea level in northern Anne Arundel County (AA Ad 108) to about 28 ft below sea level on the Broadneck Peninsula (AA Cf 134). Recent water-level trends in the Upper Patapsco aquifer are stable or recovering in the Glen Burnie area (AA Ad 108 and AA Bd 159), Broadneck Peninsula (AA Cf 134 and AA Cg 24), and south of Annapolis (AA De 128). In the Broad Creek and City of Annapolis well fields (AA De 95 and AA De 219, respectively), water levels, while fluctuating in response to short-term pumping cycles, are relatively stable.

hydrograph for observation well AA Cf 137 in the Lower Patapsco aquifer

Lower Patapsco aquifer


The most recent water levels in the Lower Patapsco aquifer range from about 77 ft above sea level in northern Anne Arundel County (AA Bd 160) to about 85 ft below sea level at the Crofton Meadows well field (AA Cc 115). Water-level trends in the Lower Patapsco aquifer are stable or recovering in the Glen Burnie area. In the Crofton Meadows well field, water levels have declined between 10 ft (AA Cc 89) and 85 ft (AA Cc 115) since 2014. The water-level trend at the Arnold well field (AA Cf 137) was relatively stable between 1988 and about 2010, declined between 2010 and 2012, and has been stable or slightly recovered since 2012 (AA Cf 137 and AA Cf 167). Water levels at the Broad Creek well field (AA De 206), while fluctuating as a result of short-term pumping cycles, appear relatively stable.

hydrograph for observation well AA Cf 166 in the Patuxent aquifer

Patuxent aquifer


The most recent water levels in the Patuxent aquifer range from about 28 ft above sea level south of Ft. Meade (AA Cb 1) to about 80 ft below sea level in the Crofton Meadows well field (AA Cc 135). Beginning in about 2006, the water-level trend has been relatively stable in the Dorsey Road well field (AA Ad 90). A temporary cessation of Patuxent pumpage from the Dorsey Road well field during the winter of 2015-16 caused water levels to recover more than 100 ft, higher than any levels recorded since 1977. In the Crofton Meadows well field (AA Cc 102 and 135), water levels have declined more than about 15 ft since about 2012. In the Arnold well field (AA Cf 166—remote test well) water levels have been stable. The increased Lower Patapsco withdrawals at Arnold resulted in a decline of more than 40 ft in a monitoring well located about 5 miles to the east (AA Cg 22); water levels appear to have stabilized over the last couple years.