Factors Affecting Water Quality in Domestic Wells in the Upper Floridan Aquifer, Southeastern United States, 1998-2005

Abstract

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The quality of our Nation's waters: water quality in the Upper Floridan aquifer and overlying surficial aquifers, southeastern United States, 1993-2010

“…The median concentration of nitrate in these wells was 3.3 mg/L and the maximum concentration was 35 mg/L. Nitrate concentrations were above the background concentration of about 0.1 mg/L (24,34,35) in more than three-fourths of the wells. Nitrate concentrations in shallow groundwater underlying the Ocala and Tampa areas were affected by the overlying land use.…”

Groundwater quality data from the National Water-Quality Assessment Project, May 2012 through December 2013

“…The Upper Floridan aquifer is a thick sequence of limestone and dolomite that is heavily used for water supply in several southeastern states (Miller, 1990). A low-permeability sequence of sand, clay, marl, limestone, and dolomite overlies the Upper Floridan aquifer over much of its areal extent (Berndt and Crandall, 2009). The study area for the gaflsus4 is defined by areas in southeastern Georgia and northeastern Florida where these low-permeability sediments form a confining unit of more than 100 ft in thickness, a total area of about 18,000 mi 2 .…”

“…The wells typically were 230 to 700 ft deep (table 4-1; appendix 4) and have a wide range of open intervals (table 4-2; appendix 4). The gaflsus4 was previously sampled in 2005 (Berndt and Crandall, 2009;Berndt and others, 2014); samples for the current phase of monitoring were collected June through September 2013.…”

Factors Affecting Public‐Supply Well Vulnerability in Two Karst Aquifers

“…Although karst aquifers occur in a wide variety of settings with varying characteristics, they are generally subject to rapid changes in flow and discharge, a high degree of surface‐water/groundwater interaction, and extreme vulnerability to water‐quality impairment (Lindsey et al ). The EA and UFA provide drinking water to millions of people, and contaminants such as nutrients and organic compounds have been documented in both aquifers (Fahlquist and Ardis ; Katz ; Berndt and Crandall ; Musgrove et al ). TANC studies of these aquifers applied numerous geochemical and hydrologic tools to assess factors controlling the transport of contaminants to a selected PSW.…”