Maryland Department of Natural Resources

Anne Arundel County Observation-Well Network

The Anne Arundel County water-level network is one of three county observation-well networks maintained by MGS and funded through county cooperative agreements. Other counties include Charles and Queen Anne’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 41 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 (6 wells), and Aquia (1 well). Frequency of measurement is 6 times a year, semiannual (spring and fall), or continuous.



Current Water-Level Trends


Aquia aquifer


Since monitoring began in 2004, 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 32.33 ft below sea level in 2020. While fluctuating by as much as ~5 feet 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 the 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 aquifer.

Magothy aquifer


Water levels in the Magothy aquifer range from 2.89 ft above sea level west of Annapolis (AA Dd 42) to 23.75 ft below sea level in Broad Neck (AA Cf 99). Overall, water levels show a relatively flat to slightly declining trend over the last few years.

Upper Patapsco aquifer


Water levels in the Upper Patapsco aquifer range from 73.05 ft above sea level in northern Anne Arundel County (AA Ad 108) to 37.07 ft below sea level at the Broad Creek Water Treatment Plant (AA De 95). Recent water-levels in the Upper Patapsco aquifer exhibit flat trends in wells in the lower east-central portion of the County, and slightly increasing trends in wells in the northern portion of the County (Glen Burnie area) and at Amberly (AA Cf 134).

Lower Patapsco aquifer


Water levels in the Lower Patapsco aquifer range from 77.26 ft above sea level in northern Anne Arundel County (AA Bd 160) to 86.18 ft below sea level in the Arnold well field (AA Cf 167). 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 respond to withdrawals but show a relatively stable trend. Recent pumpage in Crofton ranges from 1.57 million gallons per day (Nov. 2020) to 7.30 million gallons per day (Aug 2020). The water-level trend at the Arnold well field (AA Cf 137 and AA Cf 167) has remained stable. In Arnold, recent pumpage ranged from 2.28 million gallons per day (Dec 2020) to 7.60 million gallons per day (July 2020). Higher pumpage tends to occur during summer and fall, causing water levels in the observation wells to decline; lower pumpage occurs during winter and spring, causing water levels to rise.

Patuxent aquifer


Water levels in the Patuxent aquifer range from 27.73 ft above sea level south of Ft. Meade (AA Cb 1) to 112.58 ft below sea level in the Arnold well field (AA Cf 166). Water-levels near the Dorsey Road well field (AA Ad 90) fluctuate due to localized pumping but have remained relatively stable. At Severndale (AA Ce 117) and in the Crofton Meadows well field (AA Cc 102 and 135), water levels continue to decline. Recent pumpage in Crofton ranges from 1.26 million gallons per day (Aug 2020) to 6.53 million gallons per day (Nov 2020). In the Arnold well field (AA Cf 166) water levels are highly dependent on nearby withdrawals but have shown a relatively stable trend since about 2014. Recent pumpage in Arnold ranges from 1.81 million gallons per day (June 2021) to 3.85 million gallons per day (Sept 2020).