Southeast District
Assessment and Monitoring Program
Ecosummary
Lake Okeechobee
South Florida
July, 1999
by such a high mound of dirt that no one would be able
to see the lake’s waters from ground level again. Originally this was done with good intent but nevertheless
“created a travesty against nature that could never be
reversed” (Smith, P.D. 1984. A Land Remembered,).
Summary: High nutrient concentrations,
nuisance algae blooms and maintaining an
“appropriate” water level are problems. Current
water quality status: IMPAIRED.
Lake Okeechobee is a large, shallow, eutrophic lake
located in south-central Florida and is a major feature of the Kissimmee-Okeechobee Everglades System. With a surface area of 669 square miles, an
average depth of 2.7 meters, and a maximum water
storage capacity of 1.05 trillion gallons, it is the second largest freshwater lake in the continental United
States, second only to Lake Michigan. Lake
Okeechobee’s drainage basin covers more than
4,600 square miles, with an extensive network of
monitoring sites that provide data for flood control,
water supply, and water quality. Major uses of the
lake are fish and wildlife habitat, flood control, agricultural, urban and industrial water supply, prevention of saltwater intrusion, navigation,
recreation, as well as a source of water for the Everglades.
Early accounts of the lake describe it as “usually
brim full, spilling over to the watery sawgrass plain
which spread southward 100 miles or more”. The
Okeechobee hurricane of 1928 changed the look
of the land forever. Over 742 people died in the
storm and flooding that followed and Lake
Okeechobee was leveed. The lake was surrounded
Lake Okeechobee, a once natural lake and wetland system, now functions as a multipurpose regional reservoir
storing water during the wet season for use during the
dry season. Lake Okeechobee represents a crucial component of South Florida’s water supply and flood control. The lake provides a backup water source for urban
areas, irrigation water for agricultural land, recharge
water for aquifers, and is a major source of water for the
Everglades. The reclamation of the Florida Everglades
in 1850 had a profound effect on the lake. It lowered
the water level by using man-made canals that drained
to the coasts. It also involved the construction of a dike
on the southern side to stop the normal flow of water
from the lake. Agricultural canals were dug as early as
1900, to aid in the draining of lands directly south of the
lake, in order to use the rich soil as farm land.
Water quality in the lake is directly effected by its tributaries and the lake’s surrounding land uses. Dairies, cattle
ranches, and vegetable crops are the most intensive land
uses in the basin and contribute to the nutrient loading
of the lake. Urban land uses contribute only about 3%
of the total load, with the balance coming from agricultural sources. Wetlands along the flowpath to the
lake would reduce phosphorus loading, but many wetlands have been ditched to drain them for agricultural
and urban uses. Loss of these wetlands has reduced
their capacity to retain water and remove nutrients that
otherwise reach the lake. One of the potential solutions for reducing nutrient loading to Lake Okeechobee
would be the restoration of existing wetlands, and the
treatment of “first flush” runoff from rain events. High
concentrations of nutrients have contributed to the proliferation of algal blooms on the lake.
Lake Okeechobee and its associated wetlands provide
habitat for a large variety of plants and animals, including a number of rare and endangered species. Also
migratory birds and waterfowl use the lake’s marsh and
Algae blooms in Lake Okeechobee are a result
of nutrients entering the lake via basin runoff.
wetland areas for resting due to its position in the
Atlantic flyway. The ultimate goal is to protect
and improve the environmental resources of Lake
Okeechobee, and the lakes functional role in the
regional aquatic ecosystem.
Phosphorus loading from the lake’s tributaries
needs to be reduced. Internal phosphorus recycling from lake sediment to lake waters also need
to be addressed. Several past and present programs have been or are being used to achieve nutrient reduction in runoff from the watershed.
They include: Taylor Creek Headwaters Project
& TCNS, Rural Clean Waters Program, FDEP
Dairy Rule, Dairy Buy-Out Program, and
SFWMD Works of the District Rule (to establish
numeric phosphorus concentration limits for runoff from nondairy land uses). Despite these programs, phosphorus levels in the lake have
continued to increase.
Although Lake Okeechobee has been
monitored since the 1970’s, it is crucial
to the fragile ecosystem of the lake that
the programs implemented continue to
improve upon themselves and the lakes
water quality so that future generations
will enjoy the lakes many functions and
resources.
For more information: Contact the Southeast District Surface Water Quality section in Port St. Lucie
at 561/871-7662, or by email:
[email protected]