Charles County Observation-Well Network
The Charles County water-level network is one of three county observation-well networks maintained by MGS and funded through county cooperative agreements. Other counties include Anne Arundel and Queen Anne’s counties.
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 Charles County observation-well network, initiated in 1999, is currently funded through a cooperative agreement between Maryland Geological Survey and Charles County Department of Planning and Growth Management. The network currently consists of 29 wells located mainly in the central and northern part of the County. Aquifers monitored include the Patuxent (13 wells), Lower Patapsco (8 wells), Upper Patapsco (5 wells), and Magothy (3 wells). Frequency of measurement ranges from 6 times a year to semiannual (spring and fall).
Current Water Level Trends
Water levels in the Magothy aquifer continue to fluctuate in response to pumpage, (water usage), but trends show an overall decline. Water levels range from 78.38 ft below sea level at St. Charles (CH Bf 133) to 116.72 ft below sea level. The observation well at John Hanson Middle School (CH Bf 134) developed a leak in the casing and has been abandoned from the network since September 12, 2019.
Upper Patapsco aquifer
Water levels in the Upper Patapsco aquifer have shown a slightly declining trend, except for water levels at Douglas Point (CH Da 21), which shows a flat trend. Water levels range from 15.47 ft below sea level at Douglas Point (CH Da 21) to 85.93 ft below sea level at St. Charles (CH Bf 157).
Lower Patapsco aquifer
Water levels in the Lower Patapsco aquifer have shown a flat trend. Water levels at St. Charles (CH Bf 146) and Chapel Point Woods (CH De 52) show a slightly increasing trend due to a decline in usage in the Lower Patapsco aquifer. Water levels in the Lower Patapsco aquifer range from 17.13 ft below sea level at Douglas Point (CH Da 20) to 145.03 ft below sea level at La Plata (CH Ce 56).
Overall, water levels in the Patuxent aquifer continue to decline. In the northeastern part of the County at Malcom (CH Bg 18), these declines have slowed in recent years. Elsewhere in the County, water levels in the Patuxent aquifer are declining at rates of approximately 2 to 4 ft per year with the fastest declines occurring in the Bryans Road area wells (CH Bc 75, 77, and 78). Water levels in the Patuxent aquifer range from 13.38 ft below sea level in the western part of the county at Douglas Point (CH Da 18) to 106.36 ft below sea level at Chapman’s Landing (CH Bc 77). Recent pumpage in the Bryans Road area ranges from 473,000 gallons per day (June 2020) to 357,000 gallons per day (November 2019).