Scientific Investigations Report 2007-5247

Water-Level Changes in Aquifers of the Atlantic Coastal Plain, Predevelopment to 2000

By Vincent T. dePaul, Donald E. Rice, and Otto S. Zapecza

Scientific Investigations Report 2007-5247

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Abstract

The Atlantic Coastal Plain aquifer system, which underlies a large part of the east coast of the United States, is an important source of water for more than 20 million people. As the population of the region increases, further demand is being placed on those ground-water resources. To define areas of past and current declines in ground-water levels, as well as to document changes in those levels, historical water-level data from more than 4,000 wells completed in 13 regional aquifers in the Atlantic Coastal Plain were examined.

From predevelopment to 1980, substantial water-level declines occurred in many areas of the Atlantic Coastal Plain. Regional variability in water-level change in the confined aquifers of the Atlantic Coastal Plain resulted from regional differences in aquifer properties and patterns of ground-water withdrawals. Within the Northern Atlantic Coastal Plain, declines of more than 100 ft were observed in New Jersey, Delaware, Maryland, Virginia, and North Carolina. Regional declines in water levels were most widespread in the deeper aquifers that were most effectively confined—the Upper, Middle, and Lower Potomac aquifers. Within these aquifers, water levels had declined up to 200 ft in southern Virginia and to more than 100 ft in New Jersey, Delaware, Maryland, and North Carolina. Substantial water-level declines were also evident in the regional Lower Chesapeake aquifer in southeastern New Jersey; in the Castle Hayne-Piney Point aquifer in Delaware, Maryland, southern Virginia and east-central North Carolina; in the Peedee-Severn aquifer in east-central New Jersey and southeastern North Carolina; and in the Black Creek-Matawan aquifer in east-central New Jersey and east-central North Carolina. Conversely, declines were least severe in the regional Upper Chesapeake aquifer during this period.

In the Southeastern Coastal Plain, declines of more than 100 ft in the Chattahoochee River aquifer occurred in eastern South Carolina and in southwestern Georgia, where water levels had declined approximately 140 and 200 ft from prepumping conditions, respectively. Within the Upper Floridan aquifer, decline was most pronounced in the coastal areas of Georgia and northern Florida where ground-water withdrawals were at their highest. These areas included Savannah, Jesup, and Brunswick, Ga., as well as the St. Marys, Ga. and Fernandina Beach, Fla., area. Regional water levels had declined by 80 ft near Brunswick and Fernandina Beach to as much as 160 ft near Savannah.

Since 1980, water levels in many areas have continued to fall; however, in some places the rate at which levels declined has slowed. Conservation measures have served to limit withdrawals in affected areas, moderating or stabilizing water-level decline, and in some cases, resulting in substantial recovery. In other cases, increases in ground-water pumpage have resulted in continued rapid decline in water levels.

From 1980 to 2000, water levels across the regional Upper, Middle, and Lower Potomac aquifers continued to decline across large parts of Delaware, Maryland, Virginia, and North Carolina, and water levels had stabilized or recovered throughout much of Long Island and New Jersey. Substantial water-level recovery had also occurred in east-central New Jersey in the Peedee-Severn and Black Creek-Matawan aquifers and in east-central North Carolina in the Castle Hayne-Piney Point aquifer. Substantial declines from about 1980 to about 2000 occurred in the Peedee-Severn aquifer in southern New Jersey, the Beaufort-Aquia aquifer in southern Maryland, and the Black Creek-Matawan and Upper Potomac aquifers in central and southern parts of the coastal plain in North Carolina.

From 1980 to about 2000, water levels within the regional Upper Floridan aquifer had generally stabilized in response to shifting withdrawal patterns and reductions in pumpage at many places within the coastal region. Ground-water levels had stabilized and recovered at the major cones of depression at Savannah, Brunswick, and Jesup, Ga.; had remained about the same in the St. Marys, Ga. and Fernandina Beach, Fla., area; and were stable to slightly declining in the Jacksonville, Fla., area. In the Southeastern Coastal Plain, water levels in the Chattahoochee River aquifer continued to decline in eastern South Carolina, particularly in and around Charleston and Georgetown Counties; water levels recovered in Myrtle Beach


Contents

Abstract

Introduction

Atlantic Coastal Plain Aquifer System Study Area

Purpose and Scope

Sources of Data

Methods and Data Representation

Limitations of the Analysis

Water-Level Changes In Aquifers Of The Northern Atlantic Coastal Plain

Upper Chesapeake Aquifer

Lower Chesapeake Aquifer

Castle Hayne-Piney Point Aquifer

Beaufort-Aquia Aquifer

Peedee-Severn Aquifer

Black Creek-Matawan Aquifer

Upper Potomac and Magothy Aquifers

Middle Potomac Aquifer

Lower Potomac Aquifer

Water-Level Changes In Aquifers Of The Southeastern Atlantic Coastal Plain

Upper Floridan Aquifer

Pearl River Aquifer

Chattahoochee River Aquifer

Black Warrior River Aquifer

Summary

Acknowledgments

References Cited

Plate

1. Map showing the location of the Atlantic Coastal Plain aquifer system

Figures

1-3. Maps Showing—

1. Simulated potentiometric surface of the Upper Chesapeake aquifer, prior to development

2. Estimated water-level changes in the Upper Chesapeake aquifer, predevelopment to circa 1980

3. Estimated water-level changes in the Upper Chesapeake aquifer, circa 1980 to 2000

4. Selected hydrographs from wells screened in the Upper Chesapeake aquifer

5-7. Maps Showing—

5. Simulated potentiometric surface of the Lower Chesapeake aquifer, prior to development

6. Estimated water-level changes in the Lower Chesapeake aquifer, predevelopment to circa 1980

7. Estimated water-level changes in the Lower Chesapeake aquifer, circa 1980 to 2000

8. Selected hydrographs from wells screened in the Lower Chesapeake aquifer

9-11. Maps Showing—

9. Simulated potentiometric surface of the Castle Hayne-Piney Point aquifer, prior to development

10. Estimated water-level changes in the Castle Hayne-Piney Point aquifer, predevelopment to circa 1980

11. Estimated water-level changes in the Castle Hayne-Piney Point aquifer, circa 1980 to 2000

12. Selected hydrographs from wells screened in the Castle Hayne-Piney Point aquifer

13-15. Maps Showing—

13. Simulated potentiometric surface of the Beaufort-Aquia aquifer, prior to development

14. Estimated water-level changes in the Beaufort-Aquia aquifer, predevelopment to circa 1980

15. Estimated water-level changes in the Beaufort Aquia aquifer, circa 1980 to 2000

16. Selected hydrographs from wells screened in the Beaufort-Aquia aquifer

17-19. Maps Showing—

17. Simulated potentiometric surface of the Peedee-Severn aquifer, prior to development

18. Estimated water-level changes in the Peedee-Severn aquifer, predevelopment to circa 1980

19. Estimated water-level changes in the Peedee-Severn aquifer, circa 1980 to 2000

20. Selected hydrographs from wells screened in the Peedee-Severn aquifer

21-23. Maps Showing—

21. Simulated potentiometric surface of the Black Creek-Matawan aquifer, prior to development

22. Estimated water-level changes in the Black Creek-Matawan aquifer, predevelopment to circa 1980

23. Estimated water-level changes in the Black Creek-Matawan aquifer, circa 1980 to 2000

24. Selected hydrographs from wells screened in the Black Creek-Matawan aquifer

25-27. Maps Showing—

25. Simulated potentiometric surface of the Upper Potomac and Magothy aquifer, prior to development

26. Estimated water-level changes in the Upper Potomac and Magothy aquifers, predevelopment to circa 1980

27. Estimated water-level changes in the Upper Potomac and Magothy aquifers, circa 1980 to 2000

28. Selected hydrographs from wells screened in the Upper Potomac and Magothy aquifers

29-30. Maps Showing—

29. Simulated potentiometric surface of the Middle Potomac aquifer, prior to development

30. Estimated water-level changes in the Middle Potomac aquifer, predevelopment to circa 1980

31. Estimated water-level changes in the Middle Potomac aquifer, circa 1980 to 2000

32. Selected hydrographs from wells screened in the Middle Potomac aquifer

33-35. Maps Showing—

33. Simulated potentiometric surface of the Lower Potomac aquifer, prior to development

34. Estimated water-level changes in the Lower Potomac aquifer, predevelopment to circa 1980

35. Estimated water-level changes in the Lower Potomac aquifer, circa 1980 to 2000

36. Selected hydrographs from wells screened in the Lower Potomac aquifer

37-40. Maps Showing—

37. Estimated potentiometric surface of the Upper Floridan aquifer, prior to development

38. Estimated potentiometric surface of the Upper Floridan aquifer, 1980

39. Estimated water-level changes in the Upper Floridan aquifer, predevelopment to 1980

40. Water-level changes in the Upper Floridan aquifer, 1980 to 1998

41-42. Graphs Showing—

41. Selected hydrographs from wells open to the Upper Floridan aquifer, Georgia

42. Selected hydrographs from wells open to the Upper Floridan aquifer, South Carolina and Florida

43-45. Maps Showing—

43. Simulated potentiometric surface of the Pearl River aquifer, prior to development

44. Estimated water-level changes in the Pearl River aquifer, predevelopment to circa 1980

45. Estimated water-level changes in the Pearl River aquifer, circa 1980 to 2000

46. Selected hydrographs from wells screened in the Pearl River aquifer

47-49. Maps Showing—

47. Simulated potentiometric surface of the Chattahoochee River aquifer, prior to development

48. Estimated water-level changes in the Chattahoochee River aquifer, predevelopment to circa 1980

49. Estimated water-level changes in the Chattahoochee River aquifer, circa 1980 to 2000

50. Selected hydrographs from wells screened in the Chattahoochee River aquifer

51-52. Maps Showing—

51. Simulated potentiometric surface of the Black Warrior River aquifer, prior to development

52. Simulated and observed water-level changes in the Black Warrior River aquifer, predevelopment to 1980-85

Tables

1. Northern Atlantic Coastal Plain, relation of regional aquifer names and subregional aquifer names used in this study

2. Southeastern Atlantic Coastal Plain, relation of regional aquifer names and subregional aquifer names used in this study

3. Generalized time-stratigraphic correlation of Northern Atlantic and Southeastern Coastal Plain regional aquifers


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