| Altitude of the base of the surficial
aquifer system in eastern Palm Beach, Martin, and St. Lucie counties,
Florida, 1980, WRIR 99-4214 |
| Abstract: |
The boundary in the surficial aquifer system between freshwater and
saltwater is not sharp; it is a transition zone that is controlled,
in part, by the hydraulic conductivity of the aquifer. For the purposes
of this report, this transition zone will be called the saltwater
interface. Chloride concentrations greater than 100 mg/L (milligrams per liter) were considered to be evidence of saltwater mixing with
freshwater in the surficial aquifer system and indicate the presence
of the saltwater interface. The saltwater interface can have chloride
concentrations ranging from 100 to 19,000 mg/L (average chloride concentration
of seawater; Hem, 1992). The approximate location of the farthest
inland extent of the saltwater interface was defined through the evaluation
of chloride and geophysical data. Seaward of the saltwater interface
line the influence of saltwater intrusion exists above the base of
the surficial aquifer system. Landward of the line, oceanic saltwater
was not detected. Contour lines depicting the altitude of the base
of the surficial aquifer system (Miller, 1980; Miller, 1987; Shine
and others, 1989) were drawn. The intersection of the saltwater interface
line and the contour lines indicates the depth of the saltwater interface
at its greatest inland extent (the equivalent of the saltwater front
or toe) at the base of the surficial aquifer system; an exception
to this occurs when pumping induces lateral migration above the base
of the surficial aquifer system.
Hem, J.D., 1992, Study and interpretation of the chemical characteristics
of natural water, 3rd ed.: U.S. Geological Survey Water-Supply Paper
2254, 264 p.
Miller, W.L., 1980, Geological aspect of the surficial aquifer in
the Upper East Coast Planning Area, southeast Florida: U.S. Geological
Survey Water Resources Investigations Open-File Report 80-586, 2 sheets.
---1987, Lithology and base of the surficial aquifer system, Palm
Beach County: U.S. Geological Survey Water-Resources Investigations
Report 86-4067, sheet 1.
Shine, M.J., Padgett, D.G., and Barfknecht, W.M., 1989, Ground water
resources assessment of eastern Palm Beach County, Florida: South
Florida Water Management District Technical Publications 89-4, 372
p. |
| Metadata: |
ch1999cont_arc |
| Shapefile: |
ch1999cont_arc [ZIP
32 KB] |
| Online Report: |
WRIR 99-4214 |
| Browse Graphic: |
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