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Circular 1355

National Water-Quality Assessment Program

The Quality of Our Nation’s Waters

Water Quality in the Upper Floridan Aquifer and Overlying Surficial Aquifers, Southeastern United States, 1993–2010

By Marian P. Berndt, Brian G. Katz, James A. Kingsbury, and Christy A. Crandall

Thumbnail of and link to report PDF (68.5 MB)Overview

About 10 million people rely on groundwater from the Upper Floridan and surficial aquifers for drinking water. The Upper Floridan aquifer also is of primary importance to the region as a source of water for irrigation and as a source of crystal clear water that discharges to springs and streams providing recreational and tourist destinations and unique aquatic habitats. The reliance of the region on the Upper Floridan aquifer for drinking water and for the tourism and agricultural economies highlights the importance of long-term management to sustain the availability and quality of these resources.

Major Findings

  • The quality of groundwater in the Upper Floridan aquifer is among the best in the Nation
  • Nitrate concentrations commonly exceed the criterion for water discharging from springs
  • The absence of an upper confining layer and the presence of karst features increase the vulnerability of parts of the Upper Floridan aquifer to contamination from human activities
  • Alteration of groundwater flow can change geochemical conditions and increase groundwater vulnerability to contamination

Summary Report for the National Water-Quality Assessment Program Principal Aquifers Series, "The Quality of Our Nation's Waters—"

Circular 1360—Water Quality in Principal Aquifers of the United States, 1991–2010

Companion Reports

Circular 1337—Water Quality in the High Plains Aquifer, Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming, 1999–2004

Circular 1352—Water Quality in the Glacial Aquifer System, Northern United States, 1993–2009

Circular 1353—Water Quality in the Northern Atlantic Coastal Plain Surficial Aquifer System, Delaware, Maryland, New Jersey, New York, North Carolina, and Virginia, 1988–2009

Circular 1354—Water Quality in the Principal Aquifers of the Piedmont, Blue Ridge, and Valley and Ridge Regions, Eastern United States, 1993–2009

Circular 1355—Water Quality in the Upper Floridan Aquifer and Overlying Surficial Aquifers, Southeastern United States, 1993–2010

Circular 1356—Water Quality in the Mississippi Embayment–Texas Coastal Uplands Aquifer System and Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994–2008

Circular 1357—Water Quality in the Denver Basin Aquifer System, Colorado, 2003–05

Circular 1358—Water Quality in Basin-Fill Aquifers of the Southwestern United States: Arizona, California, Colorado, Nevada, New Mexico, and Utah, 1993–2009

Circular 1359—Groundwater Quality in the Columbia Plateau and Snake River Plain Basin-Fill and Basaltic-Rock Aquifers and the Hawaiian Volcanic-Rock Aquifers, Washington, Idaho, and Hawaii, 1993–2005

First posted January 21, 2015

For additional information, contact:
Chief, National Water-Quality Assessment (NAWQA) Program 
U.S. Geological Survey
413 National Center
12201 Sunrise Valley Drive
Reston, VA 20192

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Suggested citation:

Berndt, M.P., Katz, B.G., Kingsbury, J.A., and Crandall, C.A., 2014, The quality of our Nation’s waters—Water quality in the Upper Floridan aquifer and overlying surficial aquifers, southeastern United States, 1993–2010: U.S. Geological Survey Circular 1355, 72 p.,

ISSN 1067–084X (print)

ISSN 2330–5703 (online)


Chapter 1: Overview of Major Findings and Implications

Chapter 2: NAWQA Approach to Assessing Groundwater Quality

Chapter 3: Environmental and Hydrogeologic Setting

Chapter 4: Natural Processes and Human Activities That Affect Groundwater Qualityy

Chapter 5: Quality of the Groundwater Resource Used for Drinking

Chapter 6: Understanding Where and Why Key Contaminants Occur in Groundwater

References Cited



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