What is an Aquifer?
Renewal & Removal
of Groundwater -Page 1
Removal of Groundwater - Page 2
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
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
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