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Chloride and total hardness concentrations of water from the upper part of the Floridan Aquifer in St. Johns County, Florida
Data collected from 1976 to 1979 indicate large water-quality variations in the upper 300 feet of the Floridan aquifer in St. Johns County, Florida. Chloride concentrations range from less than 10 milligrams per liter in the northwestern part of the county to more than 1,000 milligrams per liter in the southeast and extreme southwest. Total hardness concentrations range from 110 milligrams per liter in the northwest to 1,700 milligrams per liter in the southeast. In most of the county, high chloride and total hardness concentrations indicate the presence of saline water that entered the aquifer during the Pleistocene Epoch and has not been flushed out. Water quality in the aquifer has also been influenced by submarine discharge in the southeast and by heavy pumpage for irrigation in the southwest. High total hardness concentrations not accompanied by high chloride values in the western part of the county may be structurally controlled or may indicate the presence of gypsum evaporite beds in the upper 300 feet of the aquifer. (USGS)
Suggested Citation
Hampson, P.S., Hayes, E.C., 1982, Chloride and total hardness concentrations of water from the upper part of the Floridan Aquifer in St. Johns County, Florida: U.S. Geological Survey Open-File Report 81-907, 3 maps :col. ;29 x 19 cm. on sheet 67 x 82 cm. folded in envelope 31 x 23 cm., https://doi.org/10.3133/ofr81907.
ISSN: 2331-1258 (online)
Publication type
Report
Publication Subtype
USGS Numbered Series
Title
Chloride and total hardness concentrations of water from the upper part of the Floridan Aquifer in St. Johns County, Florida
Series title
Open-File Report
Series number
81-907
DOI
10.3133/ofr81907
Year Published
1982
Language
ENGLISH
Description
3 maps :col. ;29 x 19 cm. on sheet 67 x 82 cm. folded in envelope 31 x 23 cm.