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Approximate Inland Extent of Saltwater Intrusion at the Base of the Biscayne Aquifer, Miami-Dade County, Florida, 2022

Scientific Investigations Map 3541
Prepared in cooperation with Miami-Dade County
By:  and 
https://doi.org/10.3133/sim3541

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Abstract

Miami-Dade County is part of a densely populated urban corridor in southeastern Florida. The Biscayne aquifer serves as Miami-Dade County’s primary drinking water source and is characterized by highly permeable karstic limestone and carbonate sand. The aquifer’s coastal location and permeable nature make it susceptible to saltwater intrusion. Monitoring the current inland extent and the rate of movement of the saltwater front in the aquifer can inform management strategies for conserving the long-term sustainability of the county’s water supply. In the 1950s, the U.S. Geological Survey published a map of the inland extent of saltwater intrusion in the Biscayne aquifer and has continued to update this map to monitor changes over time, with the most recent update published in 2018. An updated map has been created showing the approximate inland extent of saltwater intrusion in the Biscayne aquifer in eastern Miami-Dade County in 2022, with the 2018 extent shown for comparison. The inland extent of saltwater intrusion was mapped through the interpretation of borehole electromagnetic induction logs and measurements of chloride and specific conductance in groundwater samples. The location of the saltwater interface at the base of the Biscayne aquifer was represented by the 1,000-milligram-per-liter isochlor. This report describes changes in the location of the saltwater interface from 2018 to 2022. By 2022, the saltwater interface had moved farther inland in both the northern and southern parts of the county, advancing by as much as 0.3 kilometer in the north and up to 0.8 kilometer in the Model Land Area to the south. However, it remained relatively unchanged from its 2018 position in the east-central part of the county.

Suggested Citation

Zhang, J., and Renshaw, C., 2025, Approximate inland extent of saltwater intrusion at the base of the Biscayne aquifer, Miami-Dade County, Florida, 2022: U.S. Geological Survey Scientific Investigations Map 3541, 1 sheet, includes 19-p. pamphlet, https://doi.org/10.3133/sim3541.

ISSN: 2329-132X (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Mapping the Approximate Inland Extent of Saltwater Intrusion at the Base of the Biscayne Aquifer
  • Changes in the Location of the Saltwater Interface Between 2018 and 2022
  • Potential Network Improvements
  • Summary
  • References Cited
  • Glossary
Publication type Report
Publication Subtype USGS Numbered Series
Title Approximate inland extent of saltwater intrusion at the base of the Biscayne aquifer, Miami-Dade County, Florida, 2022
Series title Scientific Investigations Map
Series number 3541
DOI 10.3133/sim3541
Publication Date December 08, 2025
Year Published 2025
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Caribbean-Florida Water Science Center
Description Report: viii, 19 p.; 1 Sheet: 32.30 x 44.01 inches; Data Release
Country United States
State Florida
County Miami-Dade County
Other Geospatial Biscayne aquifer
Online Only (Y/N) Y
Additional publication details