Search USGS⌕ Search

Geology topics

David C. Andreasen

Publications and source records attributed to David C. Andreasen.

At least 73 records · Page 4Linked to original sources
USGS1996

Potentiometric Surface of the Magothy Aquifer in Southern Maryland, September 1995

A map showing the potentiometric surface of the Magothy aquifer in the Magothy Formation of Cretaceous age in southern Maryland during September 1995 was prepared from water-level measurements in 92 wells. The potentiometric surface was highest near the northwestern boundaryand outcrop area of the aquifer in topographically high areas of Anne Arundel and Prince Georges Counties. Regionally, the potentiometric surface sloped gently downward towards the southeast and the local gradients were directed toward the centers of three cones of depression that have developed in response to pumping. These cones were centeredaround well fields in the Annapolis, Waldorf, and Chalk Point areas. Ground-water levels were as low as 63 feet below sea level in the Waldorf area, more than 50 feet below sea level at Chalk Point, and almost 20 feet below sea level near Annapolis.

Open-File Report↗
USGS1996

Potentiometric Surface of the Upper Patapsco Aquifer in Southern Maryland, September 1995

A map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Cretaceous age in southern Maryland during September 1995 was prepared from water-level measurements in 42 wells. The potentiometric surface was nearly 120 feet above sea level near the northwestern boundary and outcrop area of the aquifer in topographically high areas of Anne Arundel County, and 55 feet above sea level in a similar setting in Prince Georges County. From these high areas, the potentiometic surface declined to the south and southeast toward large well fields in the Annapolis and Waldorf areas and at the Chalk Point powerplant. Ground-water levels reached nearly 30 feet below sea level in the Annapolis area, 113 feet below sea level southwest of Waldorf, and more than 30 feet below sea level at the Chalk Point powerplant.

Open-File Report↗
USGS1996

Potentiometric Surface of the Lower Patapsco Aquifer in Southern Maryland, September 1995

A map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Cretaceous age in southern Maryland during September 1995 was prepared from water-level measurements in 69 wells. The potentiometric surface was 87 feet above sea level near the northwestern boundary and outcrop area of the aquifer in topographically high areas of Anne Arundel County. From this high area, the potentiometric surface declined to the south and southeast toward large well fields at Crofton, Severndale, Arnold, Annapolis, Waldorf, LaPlata, Indian Head, and Morgantown. The ground-water levels reached 18 feet below sea level at Crofton, 62 feet below sea level at Severndale, 26 feet below sea level at Arnold, more than 20 feet below sea level near Annapolis, 160 feet below sea level in the Waldorf area, nearly 100 feet below sea level at LaPlata, more than 110 feet below sea level at Indian Head, and 75 feet below sea level at the Morgantown powerplant.

Open-File Report↗
USGS1996

The difference between the potentiometric surfaces of the Aquia aquifer of September 1982 and September 1995 in southern Maryland

A map showing the net change in the potentiometric surface of the Aquia aquifer in the Aquia Formation of Paleocene age in southern Maryland was based on water levels measured in 66 wells from September 1982 to September 1995 and shows that the decline of the potentiometric surface during the 13-year period was 20 to 30 feet in most of the area. The decline was more than 50 feet in the Lexington Park area and more than 60 feet at Solomons Island.

Maryland↗
USGS1996

The difference between the potentiometric surfaces of the Magothy Aquifer of September 1975 and September 1995 in southern Maryland

A map showing the net change in the poentiometric surface of the Magothy aquifer in the Magothy Formation of Cretaceous age in southern Maryland from September 1975 to September 1995 was based on water-level measurements in 67 wells. The map shows that the decline of the potentiometric surface during the 20-year period ranged from 2 to 21 feet in the northernmost part of the study area. The decline was greater than 40 feet in parts of southern Prince Georges County, 75 feet at Waldorf, and 28 feet at the Chalk Point powerplant.

Maryland↗
USGS1995

Potentiometric surface of the Aquia Aquifer in southern Maryland, September 1994

A map showing the potentiometric surface of the Aquia aquifer in the Aquia aquifer in the Aquia Formation of Paleocene age in southern Maryland during September 1994 was prepared from water levels measured in 74 wells. The potentiometric surface was above sea level near the northwestern boundary and outcrop area of the aquifer in topographically high areas of Anne Arundel and Prince Georges Counties, and was below sea level in the remainder of the study area. The hydraulic gradient was directed southeastward toward an extensive cone of depression around well fields at Lexington Park and Solomons Island. Ground-water levels were more than 70 feet below sea level in a 60-square-mile area surrounding the deepest part of the cone of depression and 131 feet below sea level in one well near the center of the cone.

Open-File Report↗
USGS1995

Potentiometric surface of the Magothy Aquifer in southern Maryland, September 1994

A map showing the potentiometric surface of the Magothy aquifer in the Magothy Formation of Cretaceous age in southern Maryland during September 1994 was prepared from water levels measured in 85 wells. The potentiometric surface was highest near the northwestern boundary and outcrop area of the aquifer in topographically high areas of Anne Arundel and Prince Georges Counties. Regionally, the potentiometric surface sloped gently downward toward the southeast, and the local gradients were directed toward the centers of three cones of depression that have developed in response to pumping. These cones were centered around well fields in the Annapolis, Waldorf, and Chalk Point areas. Ground-water levels were as low as 60 feet below sea level in the Waldorf area, more than 45 feet below sea level at Chalk Point, and almost 15 feet below sea level near Annapolis.

Open-File Report↗
USGS1995

Potentiometric surface of the upper Patapsco Aquifer in southern Maryland, September 1994

A map showing the potentiometric surface of the upper Patapsco aquifer in the Patapsco Formation of Cretaceous age in southern Maryland during September 1994 was prepared from water levels measured in 43 wells. The potentiometric surface was at least 70 feet above sea level near the northwestern boundary and outcrop area of the aquifer in a topographically high area of Anne Arundel County, and nearly 60 feet above sea level in a similar setting in Prince Georges County. From these high areas, the potentiometric surface declined to the south and southeast toward large well fields in the Annapolis and Waldorf areas and at the Chalk Point powerplant. Ground-water levels reached nearly 30 feet below sea level in the Annapolis area, nearly 110 feet below sea level southwest of Waldorf, and more than 25 feet below sea level at the Chalk Point powerplant.

Open-File Report↗
USGS1995

Potentiometric surface of the lower Patapsco Aquifer in southern Maryland, September 1994

A map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Cretaceous age in southern Maryland during September 1994 was prepared from water levels measured in 56 wells. The potentiometric surface was at least 104 feet above sea level near the northwestern boundary and outcrop area of the aquifer in a topographically high area of Prince Georges County, and at least 89 feet above sea level in a similar setting in Anne Arundel County. From these high areas, the potentiometric surface declined to the south and southeast toward large well fields at Crofton, Severndle, Arnold, Annapolis, Waldorf, La Plata, Indian Head, and Morgantown. The ground-water levels reached 20 feet below sea level at Crofton, 80 feet below sea level at Severndale, 25 feet below sea level at Arnold, more than 10 feet below sea level near Annapolis, more than 130 feet below sea level in the Waldorf area, more than 100 feet below sea level at La Plata an Indian Head, an nearly 80 feet below sea level at the Morgantown powerplant.

Open-File Report↗
USGS1990

The difference between the potentiometric surfaces of the Aquia Aquifer of September 1986 and September 1988 in southern Maryland

A map was prepared that shows the net change in the potentiometric surface of the Aquia aquifer (in the Paleocene Aquia Formation) in southern Maryland from the fall of 1986 to the fall of 1988. The map, based on water level measurements from 74 observation wells, shows that during the 2 year period the potentiometric surface declined less than 6 ft in most of southern Maryland but 10 ft or more in the Lexington Park and Solomons Island areas. (USGS)

Water-Resources Investigations Report↗
USGS1990

Potentiometric surface of the Magothy Aquifer in southern Maryland during September 1988

A map showing the potentiometric surface of the Magothy aquifer in southern Maryland during the fall of 1988 was prepared from water-level measurements in 83 observation wells. The potentiometric surface was highest near the northwest boundary and outcrop area of the aquifer in topographically high locations of Anne Arundel and Prince Georges Counties. The hydraulic gradient in the study area was generally southeastward or toward the centers of three cones of depression that have developed in response to pumping stresses. These cones formed around well fields in the Annapolis, Waldorf, and Chalk Point areas. The potentiometric surface of the Magothy aquifer was more than 40 ft below sea level in parts of the Waldorf and Chalk Point areas. (USGS)

Water-Resources Investigations Report↗
USGS1989

Potentiometric surface of the Aquia Aquifer in southern Maryland during the fall of 1987

A map showing the potentiometric surface of the Aquia aquifer in the Paleocene Aquia Formation in southern Maryland during the fall of 1987 was prepared by using water level measurements from 80 observation wells. The potentiometric surface was above sea level near the northeastern boundary and outcrop area of the aquifer in topographically high areas of Anne Arundel and Prince Georges Counties. The potentiometric surface was below sea level in the remainder of the study area. The hydraulic gradient was generally to the southeast toward an extensive cone of depression, which is centered around well fields near Lexington Park. Much of the cone is more than 40 ft below sea level. (USGS)

Water-Resources Investigations Report↗
USGS1989

Potentiometric surface of the Magothy Aquifer in southern Maryland during the fall of 1987

A map showing the potentiometric surface of the Magothy aquifer in the Cretaceous Magothy Formation in southern Maryland during the fall of 1987 was prepared by using water level measurements in 85 observation wells. The potentiometric surface was highest near the northwestern boundary and outcrop area of the aquifer in topographically high locations of Anne Arundel and Prince Georges Counties. The hydraulic gradient in the study area was generally southeastward or toward the centers of three cones of depression which have developed in response to pumping stresses. These cones formed around well fields in the Annapolis, Waldorf, and Chalk Point areas. The potentiometric surface of the Magothy aquifer was more than 40 ft below sea level in parts of the Waldorf and Chalk Point areas. (USGS)

Water-Resources Investigations Report↗