Biscayne Aquifer - What is an Aquifer?


What is an Aquifer?

General Information

Saltwater Intrusion

Saltwater Intrusion Animation

Renewal & Removal of Groundwater -Page 1

Renewal & Removal of Groundwater - Page 2

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An aquifer is defined as a "body of rock or regolith sufficiently permeable to conduct economically significant quantities of groundwater to springs or wells" (Skinner, 1999). Essentially, cracks or pores in the rocks of the aquifer, and the spaces in between these rocks fill with water that seeps below the surface of the land. People use wells to pump the water out of the aquifer.

Unconfined Coastal Aquifer
Unconfined Coastal Aquifer. Drawing based on images from the U.S. Geological Survey. Not drawn to scale.

Unconfined Coastal Aquifer
The Biscayne aquifer is an unconfined aquifer. This means that top portion of the aquifer is the water table. It is also a coastal aquifer because it merges with the floor of Biscayne Bay and the Atlantic Ocean.

Vulnerable to Contamination Pollution
Because the Biscayne Aquifer is close to the surface, its water supply can easily be contaminated by pollutants. The aquifer is threatened by contaminants such as: septic tank drainage, runoff from landfills, dumps and sewage, pesticides, fertilizers, gasoline and other chemicals. Contaminants may also be absorbed into the rocks of the aquifer. Water in the Biscayne aquifer flows in the direction of the ocean, but how long it takes to reach the ocean is uncertain. Depending upon location of the contaminant, the type of contaminant and the water level of the aquifer, it could take days, months, or years to leave the water supply. Also, there is the possibility of the contaminated water being drawn up by wells.

1). Skinner, Brian J., Porter, Stephen C. and Daniel B. Botkin. The Blue Planet: An Introduction to Earth System Science. 2nd ed. New York: John Wiley & Sons Inc., 1999.
2). U.S. Geological Survey. The Ground Water Atlas of the United States: Alabama, Florida, Georgia and South Carolina, HA 730-G. By James A. Miller. Published in 1990. http://capp.water.usgs.gov/gwa/ch_g/index.html
3). U.S. Geological Survey. Biscayne Aquifer, Southeast Florida Water-Resources: Investigations Report 78-107. Prepared in cooperation with the U.S. Environmental Protection Agency By H. Klein and J.E. Hull. September 1978. http://sofia.usgs.gov/publications/wri/78-107/index.html