Reports
Land subsidence monitoring to assess potential effects Of groundwater withdrawals from coastal plain aquifers In Maryland: Fall, 2021 Survey
2022, Ulizio, T.P.
Administrative Report 22-02-02
Key Results
A GPS campaign was conducted from October 18-25, 2021, to determine heights of nine 3d marks to assess the potential effect of groundwater withdrawals from aquifer systems in the Coastal Plain of Maryland. Three marks are located at major well fields in Anne Arundel County, Maryland, at the Arnold Water Treatment Plant (ARNO), the Broad Creek Water Treatment Plant (BROA), and the Crofton Meadows Water Treatment Plant (CROF). Three marks are located at or near major well fields in southern Maryland, at Cove Point State Park (COV1), Lexington Park (LEX1), and Waldorf (WAL1). An additional southern Maryland mark is located at Rosaryville State Park (ROS1), where groundwater use is relatively low. Two marks are located on the eastern shore of Maryland in the Blackwater National Wildlife Refuge in Dorchester County, at Money Stump (MSTP) and Peter’s Neck (PTNK). The marks at the Blackwater National Wildlife Refuge are located in low-lying areas near the shoreline of Chesapeake Bay where inundation, caused by relative sea-level rise, makes assessing the role of land subsidence all the more critical. The GPS data were processed using the National Geodetic Survey’s Online Positioning User Service (OPUS) Projects tool utility in the International Terrestrial Reference System of 2014. The ellipsoid heights determined through OPUS Projects processing of GPS data were 3.618 meters at ARNO, -6.209 meters at BROA, 7.059 meters at CROF, -1.53 meters at COV1, -2.09 meters at LEX1, 33.808 meters at ROS1, 28.754 meters at WAL1, -35.647 meters at MSTP, and -36.041 meters at PTNK. OPUS Projects computed height uncertainties for all marks to be +/- 0.1 cm. Uncertainty computed in the latitudinal and longitudinal positions of MGS marks is smaller than could be detected by OPUS Projects.
