Rehabilitation of impounded salt marshes
will benefit Florida's Indian River Lagoon
Natural Marsh The Indian River Lagoon system, which stretch-
es from New Smyrna Beach south to Jupiter Inlet,
acts as a breeding ground and nursery for aquatic
animals. It has the highest species diversity
of any estuary (where salt and fresh waters mix)
Sin North America, with more than 4,300 species
Low- WNW. of animals and plants. The lagoon's salt marshes
and mangrove swamps provide nursery areas for
----Upland Lagoon many species of aquatic animals. Fish, crabs and
birds are provided abundant food and protection
This is how a natural salt marsh looks. Fish and other from predators in the periodically flooded vegeta-
aquatic animals find shelter and food in the marsh. tion of the marsh. But because most of the marsh-
es are now impounded, they are shut off from the
Impounded Marsh many fish and other animals in the lagoon.
Since 1954, more than 40,000 acres of salt
Hih wa. marshes and mangrove swamps have been diked
Swoff and flooded to prevent salt marsh mosquitoes
o Ot from laying their eggs in the mud. Unfortunately,
Low wta f isolation of the marshes from the 156-mile
lagoon system adversely affected fisheries and
Dikes built to control mosquito breeding isolate the Scientists now know that only a few inches of
marsh from the lagoon and also kill vegetation, water are needed in the marshes to control
mosquito breeding. And those water levels are
Reconnected Marsh only necessary during the summer mosquito
As a part of the Indian River Lagoon SWIM
(Surface Water Improvement and Management)
High watwr Plan, thousands of acres of impounded marshes
in Brevard and Indian River counties are to be
^Lowr reconnected to the lagoon, in an attempt to
^w" partially restore the ecological function of the
marshes without compromising mosquito control
A culvert allowsfish and other aquatic animals to
travel between the marshes and the lagoon.
The St. Johns River Water Management
District, Florida Department of Health and
Rehabilitative Services, Florida Medical
Entomology Laboratory, U.S. Fish & Wildlife
Service and mosquito control districts in Brevard
and Indian River counties are now working
together on this ambitious project.
Their coordinated, long-range management
plan will mean significant improvements in fish
and wildlife resources as well as water quality
while maintaining mosquito control. Reconnect-
ing impounded marshes has never been
attempted on this scale.
How reconnection solves the problem
Culverts with flap gates (and in some cases,
pumps) will be installed in approximately 43
impoundments in Brevard and Indian River
Counties. Culverts will allow water, nutrients,
fish and other aquatic animals to travel between
the impounded marshes and the lagoon. The
culverts will remain open except during the
summer months when they will probably need
to be closed for mosquito control.
Costs dependent on land values
Total cost of the five-year project is estimated
at $9.4 million. Purchase and installation of
culverts, flapgates, pumps and other water
control structures, together with planning and
permitting, is estimated to cost $2.4 million.
Land acquisition potentially accounts for the
largest single expense for this project, estimated
at $7 million. Many of the impounded marshes
are privately owned and may have to be
purchased if the owners don't consent to
having culverts installed. "
Benefit-Cost ratio more than 5-to-1
The Indian River Lagoon serves as a nursery
ground for estuarine and ocean fish,
accounting for half of the $300 million east
Florida fish catch each year. This project will
enhance the lagoon's fisheries because juvenile
fishes will now have access to these marshes.
According to a 1989 University of Florida
study, reconnecting only 4,600 of the 40,000
acres of isolated salt marshes to the lagoon
would benefit commercial and sport fisheries by
up to $50 million. This figure is conservatively
estimated and does not include shellfish or total
economic benefits (fish processing, purchase or
rental of boats, gear, tackle and lodging).
Even after factoring in land acquisitions,
the benefits to fisheries alone are more than
five times the cost for the entire project.
Additionally, reconnecting these impounded
salt marshes to the lagoon will enhance water
quality. Several studies indicate enhanced
water quality and environmental improvements
could increase the potential value of these
marshes by as much as $44 million per year.
This project also will provide alternatives to the
management of stormwater runoff, improve
aesthetics and recreation, and increase habitat
for non-fisheries species.
For more information
about the Indian River
Lagoon SWIM program,
call Marty Smithson
at (407) 722-5364
or the District's Division
of Public Information
at (904) 329-4540.
What is SWIM?
SWIM stands for the Surface Water
Improvement and Management Act passed
by the Florida Legislature and signed into
law in 1987. SWIM provides for the clean-
up, restoration and protection of Florida's
vital water resources.
In passing the SWIM bill, the Legislature
noted that pollution and destruction of
natural systems have jeopardized some
functions of many of Florida's important
water bodies, such as the Indian River
The lagoon was one of six water bodies
the state targeted for immediate attention
by the SWIM program. Reconnecting
impounded salt marshes to the Lagoon is
just one of the many SWIM projects which
will benefit the Indian River Lagoon.