There are four aquifer systems underlying the former Bay Head Road Annex and surrounding area that the Maryland Geologic Survey (MGS) lists as “important source[s] of water supply in Anne Arundel [and other] Counties…”
Below is a diagram depicting the order and depths of these four aquifers along with corresponding confining units. Confining units are thick layers of clay or that prevent groundwater and any potential contaminants from moving between aquifers. The aquifer immediately underlying the former Bay Head Road is the Aquia. The Aquia is only aquifer likely subject to impacts by past operations at the former Bay Head Road Annex. Underlying the Aquia Aquifer is the Matawan Confining Unit. Underlying the Magothy Aquifer is the Magothy-Patapsco Confining Unit and beneath that, the Upper Patapsco Aquifer. Underlying the UPAS is the Patapsco Confining Unit and beneath that, the Lower Patapsco Aquifer. Underlying the LPAS is the Arundel Clay Confining Unit and beneath that, the Lower Patuxent Aquifer.
Shallow Groundwater Flow and PFAS Transport
At the former Bay Head Road Annex, shallow groundwater flows north/northeast, discharging to an unnamed tributary of the Little Magothy River and likely directly to the river itself. Contaminants such as PFAS which are dissolved in groundwater follow the same flow lines, which is likely the reason surface water and sediment in the unnamed tributary and the River contain detectable concentrations of PFAS.
Drinking Water Quality
People living near the former Bay Head Road Annex primarily get their drinking water from Anne Arundel County’s municipal water supply. However, there are also a small number of residences private drinking water wells in the immediate vicinity.
Anne Arundel County’s municipal water supply does not come from the shallow groundwater. The municipal drinking water is derived from the deeper Upper Patapsco, Lower Patapsco, and Patuxent Aquifers. As such, it is extremely unlikely to be impacted by contaminants released at the ground surface. Additionally, there are no county drinking water supply wells in close proximity to the former BHRA. The supply well nearest the former Bay Head Road Annex is over a mile away, to the west, southwest. Anne Arundel County also treats and tests their drinking water to ensure it meets safe drinking water standards. Customers can view the County’s Consumer Confidence Reports at (insert link). These reports provide a summary of testing done each year to ensure drinking water quality. In 2013 and 2014, the county tested its water for PFAS as part of the USEPA’s third Unregulated Contaminant Monitoring Rule sampling program. No PFAS compounds were detected. ^back to top
Of the few private drinking water wells in the area, most draw their water from the deeper Magothy aquifer and are not subject to possible impacts from PFAS originating at the former Bay Head Road Annex. There are three shallow wells north of the facility. In 2016, he Navy tested the water quality of two of the wells (the third homeowner declined sampling). No PFAS compounds were detected.
Bay Head Road Annex Cross Section