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Last updated: October 11, 2002
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How Has Managing the Wetlands of the Northern
Everglades Affected Hydrologic and Chemical Interactions with Ground
Water?
Dr. Judson Harvey and Dr. Jungyill Choi, U.S. Geological Survey
The northern Everglades wetlands have been compartmentalized into Water
Conservation Areas (WCA's) for the purpose of managing water supply
and controlling floods. The Everglades Nutrient Removal (ENR) is a
prototype wetland constructed on agricultural land to treat water
quality. The substantially different water elevations in WCA's have
enhanced hydrologic and chemical interactions between surface water and
ground water.
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Discharge occurs in wetlands adjacent to WCA-1, where the water level is
relatively high, and recharge occurs adjacent to drained farmland, where
water level is relatively low.
(Click on image for full-sized version.)
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Approximately 30% of the surface water pumped into the ENR wetland is
recharged to ground water. Some but not all of the recharged water was
captured by a seepage canal that recycles water to the ENR.
(Click on image for full-sized version.)
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Recharge from ENR wetlands to ground water is positively correlated with rate
of surface-water pumping into ENR.
(Click on the image above to view a full-sized version.)
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Dissolved mercury is easily transported across the wetland-groundwater
interface. The fate of mercury entering ground water is presently unknown.
(Click on the image above to view a full-sized version.)
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Conclusion
- Compartmentalization of the northern Everglades has enhanced
interactions between wetlands and ground water.
- Recharge occurs in WCA-1 and discharge occurs in adjacent wetlands (e.g.
eastern side of ENR and north-central part of WCA-2A). Recharge also occurs
in wetlands that border agricultural or suburban areas (e.g. western ENR
and eastern WCA-2B).
- The greater the pumping of surface water through the wetlands, the higher
the water levels, and the greater the recharge from the wetlands to groundwater.
- A significant flux amount of dissolved mercury is recharged from ENR
wetlands to ground water. The fate of Mercury and other dissolved
contaminants (such as nutrients) in ground water is presently unknown.
Research by: Judson W. Harvey1, Steven L. Krupa2,
Jungyill Choi1, Cynthia Gefvert1, 2, Robert H.
Mooney1, Susan A. King1, Larry E. Fink2,
Michael M. Reddy1, Paul F. Schuster1 (1-USGS,
2-SFWMD)
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Presented at: South Florida Restoration Science
Forum, May 17-19, 1999, Boca Raton, Florida |
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