Charles County Observation-Well Network
The Charles 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.
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, but generally show slightly declining or flat trend. Current water levels range from about 67 ft below sea level at Sun Valley (CH Be 43) to about 120 ft below sea level at St. Charles (CH Bf 133).
Upper Patapsco aquifer
Water levels in the Upper Patapsco aquifer have shown a slightly declining or flat trend in the last year. Current water levels range from 16 ft below sea level at Douglas Point (CH Da 21) to as much as about 75 ft below sea level at St. Charles (CH Bf 157).
Lower Patapsco aquifer
Water levels in the Lower Patapsco aquifer in wells in the far northern and northwestern parts of the county (CH Be 72, CH Bc 24, CH Bc 81, and CH Cc 31) have recovered by as much as 35 ft since late 2007, and have either continued to recover or have held steady since 2012. These recoveries, beginning in 2008, resulted from a drop in usage of the Lower Patapsco aquifer system in the western part of the County when the new Patuxent aquifer system wells were added to the system. Current water levels in the Lower Patapsco aquifer range from about 17 ft below sea level at Douglas Point (CH Da 20) to 137 ft below sea level at La Plata (CH Ce 56). Lower Patapsco water levels at St. Charles (CH Bf 146) and La Plata (CH Ce 56) show slight upward trends while water levels at Chapel Point Woods (CH De 52), and Douglas Point (CH Da 20) show a generally flat trend.
Water levels in the Patuxent aquifer continue to decline with the exception of the northeastern part of the County at Malcom (CH Bg 18) where water levels have stabilized in recent years. To the west, water levels in the Patuxent aquifer are declining at rates of 2.5 to 5 ft per year at Waldorf, La Plata, and Indian Head area wells, while Chapmans Landing area wells (CH Bc 75 and 77) record the fastest declines at up to 6 ft per year. Current water levels in the Patuxent aquifer range from 12 ft below sea level in the southwestern part of the county at Douglas Point (CH Da 18) to 100 ft below sea level at Chapman’s Landing (CH Bc 77). Measurements from the production well at Bryans Road (CH Bc 78) are conspicuously flat from 2015 to present, and may indicate a blockage in the measuring tube.