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 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 about 31.95 ft below sea level in 2018. 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 Cf 99 in the Magothy aquifer

Magothy aquifer


Water levels in the Magothy aquifer range from about 3.68 ft above sea level west of Annapolis (AA Dd 42) to about 31.95 ft below sea level at Deale Athletic Field (AA Fe 93). Most water levels show some stabilization within the last several years.

hydrograph for observation well AA Bd 159 in the Upper Patapsco aquifer

Upper Patapsco aquifer


Water levels in the Upper Patapsco aquifer range from about 74.49 ft above sea level in northern Anne Arundel County (AA Ad 108) to about 25.5 ft below sea level at Amberly well field (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). In the Broad Creek and City of Annapolis well fields (AA De 95 and AA De 219 respectively) and south of Annapolis (AA De 128), water levels are generally declining.

hydrograph for observation well AA Ad 102 in the Lower Patapsco aquifer

Lower Patapsco aquifer


Water levels in the Lower Patapsco aquifer range from about 77.49 ft above sea level in northern Anne Arundel County (AA Bd 160) to about 84 ft below sea level at 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 have shown lower levels between 2014 and 2019. The water-level trend at the Arnold well field (AA Cf 137 and AA Cf 167) has been stable or slightly increasing. Recent pumpage at the Crofton Meadows well field, ranges from 6,819,354 gallons per day (July 2018) to 3,483,870 gallons per day (May 2019). Recent pumpage at Arnold ranges from 6,110,483 gallons per day (July 2019) to 0 gallons per day (April 2018). Higher pumpage tends to occur during fall and summer, causing water levels in the observation wells to decline and lower pumpage occurs during winter and spring, causing water levels to rise.

hydrograph for observation well AA Cc 135 in the Patuxent aquifer

Patuxent aquifer


Water levels in the Patuxent aquifer range from about 26.43 ft above sea level south of Ft. Meade (AA Cb 1) to about 107.07 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). Recent periodic reduction in Patuxent pumpage from the Dorsey Road well field has caused water levels to recover significantly, higher than any levels recorded since the mid-1990s. In the Crofton Meadows well field (AA Cc 102 and 135), water levels are relatively stable to declining. In the Arnold well field (AA Cf 166—remote test well) water levels have been stable to slightly recovering. Recent pumpage in the Crofton Meadows well field ranges from 7,858,580 gallons per day (May 2019) to 3,539,333 gallons per day (November 2018). Recent pumpage in Arnold ranges from 3,904,322 gallons per day (May 2018) to 0 gallons per day (April 2018). Higher pumpage tends to occur during fall and summer, causing water levels in the observation wells including AA Ce 117 to decline; lower pumpage occurs during winter and spring, causing water levels to rise.