Geology topics

Andrew W. Staley

Publications and source records attributed to Andrew W. Staley.

At least 19 recordsLinked to original sources

USGS2020

Potentiometric surface maps of selected confined aquifers in southern Maryland and Maryland's eastern shore, 2019

This report presents potentiometric-surface maps of the Aquia and Magothy aquifers and the Upper Patapsco, Lower Patapsco, and Patuxent aquifer systems using water levels measured during the fall season of 2019. The potentiometric surface maps show water levels ranging from 56 feet above sea level to 163 feet below sea level in the Aquia aquifer, from 87 feet above sea level to 119 feet below sea level in the Magothy aquifer, from 114 feet above sea level to 120 feet below sea level in the Upper Patapsco aquifer system, from 136 feet above sea level to 174 feet below sea level in the Lower Patapsco aquifer system, and from 168 feet above sea level to 184 feet below sea level in the Patuxent aquifer system. Cones of depression have formed around locations with significant aquifer withdrawals. The Aquia aquifer has depressed water levels around well fields at Lexington Park, Solomons Island, and central Talbot County. Cones of depression have formed in the Magothy aquifer around well fields at Waldorf, Arnold, and Easton. The Upper Patapsco aquifer system has depressed water levels around well fields in the Annapolis-Arnold area, Waldorf, the Lexington Park-Leonardtown area, and at Easton. The Lower Patapsco aquifer system has depressed water levels around well fields at Severndale, Broad Creek, Arnold, and Crofton Meadows as well as in central and western Charles County. Cones of depression have formed in the Patuxent aquifer system around well fields at Dorsey Road, Crofton, Arnold, northwestern Charles County, and at the Chalk Point power plant.

Maryland↗

USGS2016

The Maryland Coastal Plain Aquifer Information System: A GIS-based tool for assessing groundwater resources

Groundwater is the source of drinking water for &sim;1.4 million people in the Coastal Plain Province of Maryland (USA). In addition, groundwater is essential for commercial, industrial, and agricultural uses. Approximately 0.757 × 109 L d –1 (200 million gallons/d) were withdrawn in 2010. As a result of decades of withdrawals from the coastal plain confined aquifers, groundwater levels have declined by as much as 70 m (230 ft) from estimated prepumping levels. Other issues posing challenges to long-term groundwater sustainability include degraded water quality from both man-made and natural sources, reduced stream base flow, land subsidence, and changing recharge patterns (drought) caused by climate change. In Maryland, groundwater supply is managed primarily by the Maryland Department of the Environment, which seeks to balance reasonable use of the resource with long-term sustainability. The chief goal of groundwater management in Maryland is to ensure safe and adequate supplies for all current and future users through the implementation of appropriate usage, planning, and conservation policies. To assist in that effort, the geographic information system (GIS)–based Maryland Coastal Plain Aquifer Information System was developed as a tool to help water managers access and visualize groundwater data for use in the evaluation of groundwater allocation and use permits. The system, contained within an ESRI ArcMap desktop environment, includes both interpreted and basic data for 16 aquifers and 14 confining units. Data map layers include aquifer and confining unit layer surfaces, aquifer extents, borehole information, hydraulic properties, time-series groundwater-level data, well records, and geophysical and lithologic logs. The aquifer and confining unit layer surfaces were generated specifically for the GIS system. The system also contains select groundwater-quality data and map layers that quantify groundwater and surface-water withdrawals. The aquifer information system can serve as a pre- and postprocessing environment for groundwater-flow models for use in water-supply planning, development, and management. The system also can be expanded to include features that evaluate constraints to groundwater development, such as insufficient available drawdown, degraded groundwater quality, insufficient aquifer yields, and well-field interference. Ultimately, the aquifer information system is intended to function as an interactive Web-based utility that provides a broad array of information related to groundwater resources in Maryland’s coastal plain to a wide-ranging audience, including well drillers, consultants, academia, and the general public.

Special Paper of the Geological Society of America↗

USGS2014

Potentiometric surface and water-level difference maps of selected confined aquifers in Southern Maryland and Maryland’s Eastern Shore, 1975-2013

Groundwater is the principal source of freshwater supply in most of Southern Maryland and Maryland’s Eastern Shore. It is also the source of freshwater supply used in the operation of the Calvert Cliffs, Chalk Point, and Morgantown power plants. Increased groundwater withdrawals over the last several decades have caused groundwater levels to decline. This report presents potentiometric-surface maps of the Aquia and Magothy aquifers and the Upper Patapsco, Lower Patapsco, and Patuxent aquifer systems using water levels measured during September 2013. Water-level difference maps are also presented for four of these aquifers. The water-level differences in the Aquia aquifer are shown using groundwater-level data from 1982 and 2013, while the water-level differences are presented for the Magothy aquifer using data from 1975 and 2013. Water-level difference maps for both the Upper Patapsco and Lower Patapsco aquifer systems are presented using data from 1990 and 2013. The potentiometric surface maps show water levels ranging from 165 feet above sea level to 199 feet below sea level. Water levels have declined by as much as 113 feet in the Aquia aquifer since 1982, 81 feet in the Magothy aquifer since 1975, and 61 and 95 feet in the Upper Patapsco and Lower Patapsco aquifer systems, respectively, since 1990.

Maryland, Virginia↗

USGS2012

Potentiometric surface and water-level difference maps of selected confined aquifers of Southern Maryland and Maryland's Eastern Shore, 1975-2011

Groundwater is the principal source of freshwater supply in most of Southern Maryland and Maryland's Eastern Shore. It is also the source of freshwater supply used in the operation of the Calvert Cliffs, Chalk Point, and Morgantown power plants. Increased groundwater withdrawals over the last several decades have caused groundwater levels to decline. This report presents potentiometric surface maps of the Aquia, Magothy, upper Patapsco, lower Patapsco, and Patuxent aquifers using water levels measured during September 2011. Water-level difference maps also are presented for the first four of these aquifers. The water-level differences in the Aquia aquifer are shown using groundwater-level data from 1982 and 2011, whereas the water-level differences in the Magothy aquifer are presented using data from 1975 and 2011. Water-level difference maps in both the upper Patapsco and lower Patapsco aquifers are presented using data from 1990 and 2011. These maps show cones of depression ranging from 25 to 198 feet (ft) below sea level centered on areas of major withdrawals. Water levels have declined by as much as 112 ft in the Aquia aquifer since 1982, 85 ft in the Magothy aquifer since 1975, and 47 and 71 ft in the upper Patapsco and lower Patapsco aquifers, respectively, since 1990.

Maryl↗

USGS2010

Potentiometric Surface of the Aquia Aquifer in Southern Maryland, September 2009

This report presents a map showing the potentiometric surface of the Aquia aquifer in the Aquia Formation of Paleocene age in Southern Maryland during September 2009. The map is based on water-level measurements in 82 wells. The highest measured water level was 48 feet above sea level near the northern boundary and in the outcrop area of the aquifer in the central part of Anne Arundel County. Water levels also were above sea level in Kent County and northern Queen Anne's County. Water levels were below sea level south and east of these areas and in the remainder of the study area. The hydraulic gradient increased southeastward toward a cone of depression around well fields at Lexington Park and Solomons Island. The lowest measured water level was 145 feet below sea level at the center of a cone of depression at Lexington Park. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

The Difference Between the Potentiometric Surfaces of the Aquia Aquifer in Southern Maryland, September 1982 and September 2009

This report presents a map showing the change in the potentiometric surface of the Aquia aquifer in the Aquia Formation of Paleocene age in Southern Maryland between September 1982 and September 2009. The map, based on water level differences obtained from 49 wells, shows that the potentiometric surface during the 27-year period declined from zero in the northernmost part of the study area, which is the outcrop of the aquifer, to 111 feet at Lexington Park. Lexington Park is near the southeasternmost part of the study area and approaches the downdip boundary of the aquifer. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

Potentiometric Surface of the Magothy Aquifer in Southern Maryland, September 2009

This report presents a map showing the potentiometric surface of the Magothy aquifer in the Magothy Formation of Late Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 66 wells. The highest measured water level was 85 feet above sea level near the northern boundary and outcrop area of the aquifer in the north-central part of Anne Arundel County. The potentiometric surface declined towards the south. Local hydraulic gradients were directed toward the center of a cone of depression in the Waldorf area that developed in response to pumping. Measured groundwater levels were as low as 71 feet below sea level in the Waldorf area. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

The Difference Between the Potentiometric Surfaces of the Magothy Aquifer in Southern Maryland, September 1975 and September 2009

This report presents a map showing the change in the potentiometric surface of the Magothy aquifer in the Magothy Formation of Late Cretaceous age in Southern Maryland between September 1975 and September 2009. The map, based on water level differences obtained from 48 wells, shows that during the 34-year period, the potentiometric surface had little change at the outcrop area, which is in the northernmost part of the study area, but declined 75 feet at Waldorf. Waldorf is located near the southwesternmost part of the study area, and approaches the downdip boundary of the aquifer. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

Potentiometric surface of the Upper Patapsco aquifer in southern Maryland, September 2009

This report presents a map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 65 wells. The highest measured water level was 118 feet above sea level near the northern boundary and outcrop area of the aquifer in northern Anne Arundel County. From this area, the potentiometric surface declined to the south toward a well field in the Annapolis-Arnold area, and from all directions toward three additional cones of depression. These cones are located in the Waldorf-La Plata area, Chalk Point, and the Leonardtown-Lexington Park area. The lowest measured groundwater levels were 26 feet below sea level at Annapolis, 108 feet below sea level south of Waldorf, 60 feet below sea level at Chalk Point, and 83 feet below sea level at Leonardtown. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

The difference between the potentiometric surfaces of the Upper Patapsco aquifer in southern Maryland, September 1990 and September 2009

This report presents a map showing the change in the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland between September 1990 and September 2009. The map, based on water level differences obtained from 33 wells, shows that during the 19-year period, the change in the potentiometric surface ranged from zero at the edge of the outcrop area in northern Anne Arundel County to a decline of 20 feet at Broad Creek, 16 feet near Arnold, 32 feet at Waldorf, 37 feet at the Chalk Point power plant, and 43 feet at Lexington Park. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

Potentiometric Surface of the Lower Patapsco Aquifer in Southern Maryland, September 2009

This report presents a map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 64 wells. The highest measured water level was 110 feet above sea level near the northwestern boundary and outcrop area of the aquifer in northern Prince George's County. From this area, the potentiometric surface declined towards well fields at Severndale, Broad Creek, and Arnold. The measured groundwater levels were 99 feet below sea level at Severndale, 50 feet below sea level at Broad Creek, and 36 feet below sea level at Arnold. There was also a cone of depression in Charles County that includes Waldorf, La Plata, Indian Head, and the Morgantown power plant. The groundwater levels measured were as low as 215 feet below sea level at Waldorf, 149 feet below sea level at La Plata, 121 feet below sea level at Indian Head, and 96 feet below sea level at the Morgantown power plant. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

Difference between the potentiometric surfaces of the Lower Patapsco aquifer in southern Maryland, September 1990 and September 2009

This report presents a map showing the change in the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland between September 1990 and September 2009. The map, based on water level differences obtained from 45 wells, shows that the change of the potentiometric surface during the 19-year period ranged from increases of 25 feet at Indian Head and 4 feet near the outcrop area in Glen Burnie, to declines of 35 feet at Arnold, 56 feet at Severndale, 28 feet at Crofton Meadows, 73 feet at Waldorf, 79 feet near La Plata, 35 feet at the Morgantown power plant, and 32 feet at Swan Point. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2010

Potentiometric Surface of the Patuxent Aquifer in Southern Maryland, September 2009

This report presents a map showing the potentiometric surface of the Patuxent aquifer in the Patuxent Formation of Early Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 42 wells. The highest measured water level was 169 feet above sea level in the outcrop area of the aquifer in northern Prince George's County. From this area, the potentiometric surface declined south towards well fields at Glen Burnie, Bryans Road, the Morgantown power plant, and the Chalk Point power plant. The measured groundwater levels were 78 feet below sea level at Glen Burnie, 56 feet below sea level at Bryans Road, 29 feet below sea level at the Morgantown power plant, and 28 feet below sea level at the Chalk Point power plant. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Open-File Report↗

USGS2009

Potentiometric Surface of the Aquia Aquifer in Southern Maryland, September 2007

This report presents a map showing the potentiometric surface of the Aquia aquifer in the Aquia Formation of Paleocene age in Southern Maryland during September 2007. The map is based on water-level measurements in 85 wells. The highest measured water level was 50 feet above sea level near the northern boundary and outcrop area of the aquifer in the central part of Anne Arundel County, and was below sea level just south of this area and in the remainder of the study area. The hydraulic gradient increased southeastward toward an extensive cone of depression around well fields at Lexington Park and Solomons Island. A water level measured west of the Cheasapeake Beach area has declined to 57 feet below sea level due to increased withdrawals. The lowest water level measured was 162 feet below sea level at the center of a cone of depression at Lexington Park.

Open-File Report↗

USGS2009

The Difference Between the Potentiometric Surfaces of the Aquia Aquifer in Southern Maryland, September 1982 and September 2007

This report presents a map showing the change in the potentiometric surface of the Aquia aquifer in the Aquia Formation of Paleocene age in Southern Maryland for September 1982 and September 2007. The map, based on water-level measurements in 53 wells, shows that the potentiometric surface during the 25-year period declined from zero in the northernmost part of the study area, which is the outcrop of the aquifer, to 117 feet at Lexington Park. Lexington Park is near the southeasternmost part of the study area and approaches the downdip boundary of the aquifer.

Open-File Report↗

USGS2009

Potentiometric Surface of the Magothy Aquifer in Southern Maryland, September 2007

This report presents a map showing the potentiometric surface of the Magothy aquifer in the Magothy Formation of Late Cretaceous age in Southern Maryland during September 2007. The map is based on water-level measurements in 69 wells. The highest measured water level was 85 feet above sea level near the northern boundary and outcrop area of the aquifer in the north-central part of Anne Arundel County. The potentiometric surface declined towards the south. Local gradients were directed toward the center of a cone of depression in the Waldorf area that developed in response to pumping. Measured ground-water levels were as low as 90 feet below sea level in the Waldorf area.

Open-File Report↗

USGS2009

The Difference Between the Potentiometric Surfaces of the Magothy Aquifer in Southern Maryland, September 1975 and September 2007

This report presents a map showing the change in the potentiometric surface of the Magothy aquifer in the Magothy Formation of Late Cretaceous age in Southern Maryland for September 1975 and September 2007. The map, based on water-level measurements in 51 wells, shows that during the 32-year period, the potentiometric surface had no change at the outcrop area, which is in the northernmost part of the study area, but declined 90 feet at Waldorf. Waldorf is located near the southwesternmost part of the study area, and approaches the downdip boundary of the aquifer.

Open-File Report↗

USGS2009

Potentiometric Surface of the Upper Patapsco Aquifer in Southern Maryland, September 2007

This report presents a map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2007. The map is based on water-level measurements in 50 wells. The highest measured water level was 120 feet above sea level near the northern boundary and outcrop area of the aquifer in northern Anne Arundel County. From this area, the potentiometric surface declined to the south toward a well field in the Annapolis-Arnold area, and from all directions toward four cones of depression. These cones are located in the Waldorf-La Plata area, Chalk Point-Prince Frederick area, Swan Point subdivision in southern Charles County, and the Lexington Park-St. Inigoes area. The lowest measured ground-water level was 44 feet below sea level at Arnold, 106 feet below sea level south of Waldorf, 54 feet below sea level at Swan Point, 59 feet below sea level at Chalk Point, and 58 feet below sea level at Lexington Park.

Open-File Report↗