Fighting Water Hyacinth In Orange Creek

At first glance, Florida wouldn't seem a likely candidate for elaborate water conservation efforts. The state is filled with expansive wetland ranges and surrounded on three sides by water.

However, not all water surrounding the state – nor in its many wetlands, lakes, rivers and streams – is suitable for drinking or other human use. Fickle weather patterns include long spans of wet weather followed by extended dry periods that create highly unpredictable water tables and produce a complex water management challenge.

Fortunately, Florida's leaders and water experts recognized many decades ago a need to conserve the state's water. As a result, legislators passed the 1972 Water Resources Act to ensure its continued availability. The act established five water management districts covering the entire state, with responsibilities including conservation and allocation of water supply, water quality, flood protection and natural systems management.

One such district, the St. Johns River Water Management District, covers a massive 12,283 square miles – about 7.8 million acres, or 23 percent of Florida's total area. Within its 18-county service area in northeast and east-central Florida, the St. Johns District serves 100 municipalities and employs about 700 people. The St. Johns District owns or manages more than 560,000 acres of land, acquired for the purposes of water management, water supply, and the restoration, conservation and protection of water resources. These lands largely consist of wetlands or historically wet areas.

Balancing restoration and public needs

When the St. Johns District buys land, it provides the public with far-reaching benefits, including: protecting wildlife and plant habitats, opening land for recreation, providing a place for environmental education and preserving a “natural” part of Florida for future generations. The district looks for priority lands needing protection, such as floodplains, sensitive wetlands and groundwater recharge areas.

Ninety-eight percent of the District's land is open to the public for activities compatible with conservation, such as hiking, biking, wildlife viewing, canoeing, camping, hunting and fishing. The remaining land is closed for ongoing construction or conservation projects.

Every year, the St. Johns River Water Management District develops a land management plan to balance traditional land, recreation and water uses with water resource protection, habitat diversification, and wildlife habitat restoration goals. The district carefully responds to demands from public and private interests for numerous land uses, including recreational activities such as hunting, camping and boating; and commercial uses, such as radio tower sites, utility easements and agriculture.

From farmland to creek: restoring a waterway

A leader in many ambitious restoration projects, the St. Johns District began work on the Orange Creek Restoration Area in 1998. The Orange Creek Restoration Area covers a 3,415- acre tributary waterway located about 20 miles north of Ocala, Fla., near Florida's Orange Lake. In partnership with the U.S. Department of Agriculture's Natural Resource Conservation Service (NRCS), the St. Johns District purchased the tributary waterway for $5.2 million in 1998 in an effort to improve water quality and restore wetlands.

The Orange Creek project presented significant engineering challenges because the District wanted to remove virtually all man-made drainage features. By removing the drainages, St. Johns could restore the former wetland and wildlife communities, while also creating important wetland functions, such as improved flood control and water quality maintenance.

In the 1930s, private landowners excavated a canal through vast sawgrass marshes and wet prairies in the eastern portion of Orange Lake. The man-made channel, Orange Creek, became part of a massive levee and canal system that converted 1,500 acres of marsh for agricultural use – primarily row crop production and cattle grazing.

Water from Orange Lake entered the channel to flow through the property, eventually reaching the Ocklawaha and St. Johns Rivers. While the resulting land was fertile for agriculture, its drainage created significant water quality problems for the St. Johns River.

“Because Orange Creek flowed into the river, large amounts of nutrients from the farm fed into the St. Johns River, making it difficult to maintain the water quality,” says Johnnie Drew, Invasive Plant Technical Supervisor, St. Johns River Water Management District.

With the 1998 land acquisition, the District planned to restore the area to its natural state and reduce the chemical load flowing into the St. Johns River. The final restoration phase, completed during the summer of 2001, involved removing 3.4 miles of levee, including 270,000 cubic yards of material, constructing eight habitat islands and planting more than 40,000 cordgrass plugs to restore the marsh grasses for erosion control and wildlife habitat.

Thanks in part to the restoration project, Orange Creek soon became home to a growing number of native species, including wood storks, bald eagles, Florida sandhill cranes and snowy egrets. A variety of waterfowl, including the mottled duck, hooded merganser and blue-winged teal, also use the wetland prairies and former farm fields as foraging and roosting sites. And, the area provides habitat for glossy ibis, northern harrier, turkey, alligator and white-tailed deer.

Water hyacinth takes control in creek

When the St. Johns District bulldozed the levees and first flooded the Orange Creek Restoration Area in 2000, open water allowed recreationalists, fishermen and bird watchers to easily navigate the area with canoes and small boats. However, dry periods in 2002 and 2003 left water levels at less than a foot deep, restricting access and reducing food sources and habitat. Receding water levels allowed seed germination from several species of native and exotic plants in the substrate.

When the water levels rose again, floating invaders such as frogs-bit and water hyacinth grew rapidly, and the water became thick with invasive plants. Today, the site is virtually solid vegetation, with waters unnavigable except by airboat. Dense, invasive vegetation such as cattail, frogs-bit and in particular water hyacinth, crowds out wildlife species by diminishing desirable food sources and habitat.

Water hyacinth has long, fibrous roots that float freely beneath the plant, rather than anchoring the plant in the substrate. The leaves and roots of water hyacinth then intertwine to form extensive, impenetrable mats in the water. These dense mats, intermixed with native vegetation from the drought years, impede navigation by most watercraft and cause a decline in submersed aquatic vegetation. In addition, the thick mats of vegetation create undesirable conditions for many native wildlife species. Water beneath these mats is anaerobic and unsuitable for fish and most other invertebrates.

Restoring a creek with native vegetation and wildlife. In the spring of 2004, the St. Johns District set out to restore access to the Orange Creek area. Specifically, the District aimed to create watercraft trails in two different locations, with one area as a boat launch where duck hunters can paddle into the marsh, and the other a recreational canoe launch for bird-watchers, fishermen and other outdoors enthusiasts. In addition, the District sought to create more open water to attract additional wildlife.

To control the frogs-bit and water hyacinth mats, the District turned to Habitat® herbicide, a new Smart Herbicide™ from BASF. Smart Herbicides such as Habitat provide intelligent, long-term vegetation control by affecting enzymes found only in plants – not birds, mammals, fish, insects or humans.

Habitat breaks down quickly in water, allowing desirable vegetation to germinate and repopulate a treated site. Because it is considered a lowvolume herbicide, it provides more control with less chemical load on the environment, compared to other herbicides.

“Frogs-bit and water hyacinth are among the toughest plants that we have to control,” Drew says. “Using Habitat, we hope to give the public some of their land back. Other products are available for similar applications, but they don't work as well on these plants. Based on previous work with Habitat, we were confident that it could help us reach our goal on the first application.”

Using airboats fitted with spray tanks, St. Johns District applicators sprayed 25 acres of frogs-bit, cattail and water hyacinth with a tank mixture of 100 gallons of water and 32 ounces of Habitat herbicide per acre. In collaboration with researchers from the University of Florida, the District is also experimenting with rates as low as 16 ounces of Habitat per acre to evaluate selectivity and species diversity.

“In other areas, we've used 32 ounces of Habitat per acre with excellent results,” Drew said. “With that rate, you can take out Chinese tallow in standing water as well as eliminate frogs-bit and water hyacinth.”

The St. Johns District determines the effectiveness of herbicide treatments by measuring re-growth rates and percent of target species controlled. While applicators can eliminate most target plants on the first treatment, the District continually monitors sites at regular intervals for re-growth, watching for new infestations or re-sprouting from seed banks in the substrate. If any re-treatments are needed, the District makes a second spot application.

The District expects native wildlife such as ducks, herons and egrets to return to their nesting areas in the Orange Creek area in a matter of months once the frogs-bit and water hyacinth mat is reduced and the waters open. Ultimately, the District hopes that boaters, duck hunters, fishermen and bird watchers will take advantage of the restored habitat in the Orange Creek area.

Water management remains one of state's greatest challenges. Conserving, protecting and restoring natural systems, while ensuring an adequate supply of water, remains one of Florida's greatest challenges. Through dedicated management methods, including mechanical removal, prescribed burning and herbicide treatments, the St. Johns River Water Management District has made real progress in reducing and controlling the spread of invasive and exotic plants. The District has also increased the number of acres returned to native states, which has led to increased native wildlife and wetland plant species.

“The St. Johns District uses Habitat herbicide because it reduces the number of our site visits and treatments. Without Habitat, we would be hardpressed to find an alternative herbicide that can cost-effectively control many invasive aquatic plants, as well as invasive woody species in standing water,” says Drew. “In addition, the public appreciates our restoration efforts and our ability to control nearly all the invasive vegetation on the first visit, so that they can quickly enjoy the wildlife and recreational activities on Florida's waters.”