ECOLOGICAL SETTING

Subregion 2 includes the Lake Okeechobee, Everglades Agricultural Area (EAA), Caloosahatchee and Upper East Coast basins. Each basin is unique but affected by conditions in the other basins. All have been substantially altered by flood control, drainage and water supply projects. A series of canals, levees, dikes and structures control a large part of the water in this subregion. Except for rainfall, the largest source of water to Lake Okeechobee comes from the Kissimmee River.

LAKE OKEECHOBEE BASIN

The Lake Okeechobee basin includes Lake Okeechobee, Fisheating Creek, Taylor Creek, Nubbin Slough, the Indian Prairie and Harney Pond Canals and the area that drains to each of those water bodies in Martin, Okeechobee, Highlands, Glades, Hendry and Palm Beach Counties. Drainage from Clewiston and adjacent agricultural areas enters the lake through the Industrial Canal and the S-4 Pump Station. As part of the flood control system, eight pump stations on the south rim of the lake also periodically backpump water into the lake from a portion of the EAA. Except for Fisheating Creek, all of the lake’s tributaries have been channelized with flows controlled by either pump stations or gated structures.

The lowering of its water level and the construction of an encompassing dike have modified Lake Okeechobee. These actions reduced its size and isolated it from its original extensive, dynamic system of littoral zone and floodplain. As a result of the managed water levels that existed between the early 1950s to the late 1970s, a new diverse 150 square mile marsh formed within the now well-defined 730 square mile lake.

Although the current configuration of the lake was designed primarily to provide drainage, flood control and water supply benefits, the relatively shallow water of the lake and new littoral marsh provide a major wildlife habitat for wading birds, waterfowl and other wildlife, including a number of federal and state listed species. During droughts, the lake ecosystem serves as a regional refuge for many types of birds. Lake Okeechobee is a major recreational resource that provides opportunities for hunting, boating, ecotourism and is a renowned freshwater fishing area. It also supports a commercial fishing industry. The Okeechobee Waterway, a Corps of Engineers (COE) maintained navigational route which crosses the lake, extends 152 miles from the Gulf of Mexico at Fort Myers to the Atlantic Ocean at Stuart.

A COE adopted lake regulation schedule is a compromise between the demand for high lake levels for water supply and lower levels which will provide storage capacity to protect the watershed from flooding during tropical storms. During dry periods, the shallow lake can hold sufficient water to serve as a backup water recharge source for the Biscayne Aquifer and a large part of the surficial aquifer in Palm Beach County. Together these aquifers serve the 4.5 million people and agricultural needs in Southeast Florida. Environmental water releases can be made through the main canal system to the Water Conservation Areas.

By far, the single largest demand on Lake Okeechobee is to provide water for agricultural irrigation in the EAA south of the Lake and in the St. Lucie and Caloosahatchee basins. Land to the north also receives irrigation water. Five communities withdraw drinking water directly from the lake. The City of Fort Myers depends upon the lake to ensure the quantity and quality of the supply of drinking water it withdraws from the Caloosahatchee River. In the future, maintenance of minimum flows and levels within the downstream natural system will place additional demands on the lake. Urban demands are also expected to steadily increase.

EVERGLADES AGRICULTURAL AREA BASIN

The 700,000-acre (1,100 square mile) EAA lies between Lake Okeechobee and the Water Conservation Areas (WCAs). The area was originally part of the sawgrass dominated Everglades. A broad pond apple forest existed along the south shore of the lake. Water flowed out of the lake through stream channels in the natural muck berm formed by the pond apple forest. During periods of high water, sheetflow occurred over the entire southern rim of the lake.

Near the end of the last century and the beginning of this century, efforts were begun to lower the water level in Lake Okeechobee and to drain the Everglades. These efforts attracted settlers to the area south of the lake to farm the organic soils. A muck levee was constructed on the southern side of Lake Okeechobee to provide flood protection to residents. Although the Everglades Drainage District constructed levees, locks, dams and 440 miles of canals, flooding from the hurricane of 1928 killed over 2000 people in the EAA.

In 1930, the Federal Government became involved and construction of the Herbert Hoover Dike around Lake Okeechobee began. In the following years, over drainage during droughts caused coastal salt water intrusion and muck fires in the Everglades while hurricanes continued to result in property damage. As a result of these conditions, the U. S. Army Corps of Engineers (COE) was authorized to create the present Central and South Florida Flood Control Project.

Soils in the EAA support about 550,000 acres planted in sugarcane, vegetables, rice and sod. Water levels within the EAA are managed through a system of canals, structures, and pumps that facilitate flood control and irrigation. The area includes rural communities with a total population of about 55,000 people. EAA canals and flooded fields serve as habitat for wading birds, migratory shore birds and other biota, including listed species such as the wood stork. At the southern end of the EAA there are about 68,000 acres that were impacted by drainage and are now managed for recreational activities. On most of this property, hydrologic restoration is either under way or planned.

This basin includes the Caloosahatchee River watershed in Glades, Hendry, Lee, and Charlotte Counties; and the Caloosahatchee Estuary on which the cities of Fort Myers, and Cape Coral are located. The Caloosahatchee Estuary, Pine Island Sound, Matlacha Pass and San Carlos Bay in Lee County are included in the lower Charlotte Harbor Estuary as part of the National Estuarine Program. The remaining northern portions of the Charlotte Harbor Estuary in Charlotte County into which the Peace and Myakka Rivers discharge are under the jurisdiction of the Southwest Florida Water Management District. Five national wildlife refuges, four State aquatic preserves and two State land preserves are part of the area included in this National Estuary Program. The system provides habitat for over 30 protected species and supports highly productive fisheries.

The southwest coastal portion of this basin is an area experiencing rapid population growth. The basin has a high rate of land conversion to agriculture, primarily citrus. This is the result of the movement of citrus farming to Southwest Florida following several severe freezes in Central Florida in the mid-1980s.

The slash pine forests of southwest Florida have been identified as an endangered ecosystem. Within this basin are areas of hydric pine flatwoods, which have significant ecological and hydrological value. Plant species diversity is high, with over 900 species, including 85 protected species. At least 21 Federal and State listed animal species are supported by the flatwoods communities which are also important to ground-water recharge.

The Upper East Coast Basin forms the northeastern portion of the South Florida ecosystem. It includes St. Lucie, Martin, and northern Palm Beach counties. Basin physiography is dominated by a ridge and swale, terrace and bar topography that has created the coastal barrier islands, Indian River Lagoon, Atlantic Coastal Ridge, and western flatlands.

This variation in topography has given rise to a diversity of habitats, ranging from rich estuarine seagrass beds to xeric coastal scrub, extensive pine flatwoods, and depressional freshwater wetlands. These habitats support several listed species, including West Indian manatee, Florida scrub jay, gopher tortoise, red-cockaded woodpecker, and Florida sandhill crane. The coastal estuarine lagoon system is an important resource of aesthetic, economic, recreational, and biological value. Significant areas within this basin are included in the Indian River Lagoon National Estuary Program. The Indian River Lagoon is the most diverse estuary in the U. S., with more than 4,300 species of plants and animals, including 36 that are rare and endangered.

Two river systems, the St. Lucie and Loxahatchee Rivers, breach the Coastal Ridge to drain the western flatlands. Portions of both rivers have been channelized, and the St. Lucie River has been directly connected via the St. Lucie Canal, to Lake Okeechobee. A major canal system has been constructed in Martin and St. Lucie Counties which has increased the size of the drainage basin for both the St. Lucie River system and the Indian River Lagoon. As a result, inflows of freshwater have been altered in quantity, quality and timing. Ecosystem disruption and environmental damage have resulted.

LINKAGE TO THE TOTAL SYSTEM

LAKE OKEECHOBEE BASIN

EVERGLADES AGRICULTURAL AREA BASIN

CALOOSAHATCHEE BASIN

UPPER EAST COAST BASIN

The Upper East Coast basin also has man-made hydrological connections to Lake Okeechobee and the Everglades Agricultural Area via the St. Lucie Canal (C-44) and the West Palm Beach Canal (C-51). Regulatory and flood control water releases from these basins directly impact the estuaries and groundwater resources of this basin while diverting the water from its natural flow path into downstream subregions. C-51 Canal discharges have had a quantity and quality impact on the Lake Worth Lagoon in the Lower East Coast Subregion.

To restore the Greater Lake Okeechobee Subregion, the problems of the unnatural timing and quantity of the water entering, within, and leaving the subregion must be solved. Excess lake water releases which are currently discharged to the east and west coasts disrupt the ecology of the estuaries. Additional water storage is needed to restore natural hydropatterns such as more natural water deliveries to the Everglades. Any solution must also protect the lake from prolonged periods of high and low water.

Water quality is a major concern throughout the subregion. Problems caused by pollutants such as mercury, dissolved solids, sediment transport, and nutrients especially phosphorus have affected the majority of subregion water bodies. These water quality problems are also discharged to other subregions.

LAKE OKEECHOBEE BASIN

Ecosystem problems in Lake Okeechobee are primarily a result of nutrient runoff from ranching, dairy, and agricultural lands; a lake regulation schedule which places water supply and flood control concerns ahead of the ecological health of the lake; and the invasion by exotic plants. Nutrient enrichment has caused major alterations in the ecology of the Lake. Algal blooms affect the lake on a regular basis. Major increases have occurred in the populations of blue-green algae and pollution-tolerant benthic animals.

Alteration of native littoral zone plant communities is linked to several factors. Since the native plant community developed under low nutrient conditions, the present high nutrient content of lake water has altered parts of that community. Cattails have expanded greatly over the last few decades. Prolonged high lake water levels suppress annual plant reproduction and impact the willow community, both of which are important to wildlife.

There has also been a major invasion of exotic plants. Melaleuca has spread over thousands of acres of marshland; torpedo grass has covered large expanses of the native moist soil plant community; while water hyacinths have proven to be a threat to navigation. Proliferation of various exotic species demands on-going remedial actions as well as research to improve control agents and methods. Because current control methods can also cause environmental problems, an increased effort to develop biological control methods is needed.

Special attention is focused on reducing excessive nutrient loading from the agricultural areas north of the Lake. Since the 1970s, agricultural activities, including dairy and beef cattle ranching, have been recognized as sources of excessive phosphorus loading to the Lake and the probable cause of accelerated eutrophication. There have been major efforts to reduce phosphorus loads and significant progress has been made, particularly in reducing loading from dairies. However, with the average annual phosphorus load to the lake currently exceeding the target by about 100 tons a year, much work remains to be done.

An evaluation has been initiated to identify sources and cleanup options for problem dairies. . Research also is being conducted to quantify the amount of phosphorus load reduction that might be achieved by the removal of contaminated sediments from ditches and canals in the watershed. An effort to restore overdrained wetlands in the basin might also prove to be very beneficial. Additionally, under a cooperative program with the University of Florida and Archbold Biological Station, research is being conducted to identify and optimize beef cattle ranching practices that will reduce nutrient loads in stormwater runoff and drainage discharges. The long-term goals of this project are to optimize beef cattle BMPs to ensure both economically and environmentally sustainable beef cattle practices communicate these optimized BMPs to ranchers and enhance a beef cattle management decision support system.

A goal of achieving more natural flows from the Lake into the Everglades and other parts of the natural system, including a reduction of the unnatural flow of water to the east and west coast estuaries, is critical to restoration success. Success in these efforts would provide significant ecological and commercial benefits far beyond the shores of Lake Okeechobee. However, the true test of the restoration effort will be its ability to achieve this goal while also reducing current lake high water level impacts and improving the ecological health of the lake. This restoration effort must include methods and locations for the storage of excess water outside of the lake and subregion.

EVERGLADES AGRICULTURAL AREA BASIN

Soil subsidence, caused primarily by microbial oxidation of organic matter under aerobic conditions, is a major ecological issue in the EAA. Not only does it cause the loss of a valuable resource, it also degrades water quality. Although drainage has caused significant subsidence over a 50-year period ( at an average rate of 1.2 inches per year), improvements in water table management have effectively reduced this rate to about 0.56 inches per year.

The most practical method to reduce subsidence is to maintain water levels as close to the soil surface as possible. The more soil within the profile that is inundated, the less oxidation occurs. Growers have already made important changes by including rice in their sugarcane rotations, thus increasing the use of summer flood waters and growing crops at higher water tables. These techniques help control subsidence and permit more water storage in the EAA. Limited research to breed and select sugarcane cultivars adapted to higher water tables urgently needs to be expanded. Profitably growing sugarcane at higher water tables in the EAA is critical to both sustaining production and allowing the EAA to contribute positively to the ecology of other areas.

The quality of drainage water released from the EAA to the WCAs, including the Loxahatchee National Wildlife Refuge, has been a significant issue that has received more attention than other EAA related issues. Three major programs are in place to lower the phosphorus content of EAA drainage water. They are: (1.) use of on-farm Best Management Practices to treat water before it leaves the farms; (2.) the Everglades Nutrient Removal Project (ENR), a 3,800 acre prototype STA between sugarcane fields and the Refuge and (3.) design of up to 40,000 acres of Stormwater Treatment Areas (STAs).

The amount of phosphorus that can be released to the WCAs without unbalancing the system is still controversial and yet to be determined through ongoing research. However, through two of the three programs mentioned above, improvements are already being achieved as is illustrated below:

• Between May 1, 1996 and April 30, 1997, on-farm BMPs reduced the annual average EAA phosphorus load to the WCAs by 50%.
• Between June 1996 and June 1997, the ENR project reduced the concentration of inflow phosphorus approximately 80% before outflow into the Refuge.

CALOOSAHATCHEE BASIN

Originally, the Caloosahatchee River was a shallow, meandering stream with headwaters at the marshes in and around Lake Hicpochee. Drainage and navigation efforts resulted in the channelization of the stream and its connection to Lake Okeechobee. Over a number of decades, residential, commercial and agricultural development in the basin has resulted in the destruction of natural resources including the filling of wetlands, clearing of forests and the lowering of the ground water table over a large area. Development of the basin has also lead to an increase in nutrient loading to the basin’s aquatic systems. Drainage has caused high volume, damaging discharges to the estuary during the wet season and unnaturally low flows during the dry season. High flow problems are compounded by periodic, large-volume regulatory releases from Lake Okeechobee. Such extremes threaten oyster bars, seagrass beds, the associated benthic community and the area’s ability to serve as an estuarine nursery.

The Charlotte Harbor estuarine ecosystem has experienced significant habitat loss and water quality degradation over the last 30-50 years due to human activity in the basin. Seagrass and saltmarsh acreage decreased 29 and 51 percent, respectively, from 1945 to 1982. Nutrients, especially nitrogen, entering the estuary have been increasing for the past 15-20 years.

Conversion of uplands and pasture lands to citrus farming is expected to continue. There is concern about potential effects on plants, wildlife, and their habitats and on surface and groundwater quality. Additional irrigation and drainage demands cause concern over the potential impacts on water-table levels.

Slash pine forest ecosystem acreage in Southwest Florida has steadily declined. Large acreage’s of hydric pine flatwoods have been lost to logging, development, and agriculture activities. Habitat destruction from residential and commercial development and citrus conversion continues. Melaleuca and other invasive exotic plants are a serious ecological problem.

Alterations in hydrology have been the major problem in the Upper East Coast Basin. Much of the natural area of the Upper East Coast was first converted to citrus groves and cattle range and pasture. Now urban development is rapidly expanding westward into these rural areas and increasingly fragmenting and eliminating natural communities.

Estuarine hydrology has been severely affected by construction of the drainage canal system, artificial stabilization of ocean inlets, development of the Intracoastal Waterway, and construction of causeways across the lagoons. Terrestrial hydrology has been affected by the drainage works, which shorten and sharpen hydroperiods. Abrupt flood-control pulses of fresh water released from water management canals to Lake Worth and the Indian River Lagoon threaten estuarine productivity. A planned divide structure in the L-8 Canal will send additional water into Lake Okeechobee instead of into WCA 1, the Loxahatchee Slough or the Lake Worth Lagoon. During periods of abundant rainfall, this additional water will increase high lake stage and estuarine discharge impacts.

Long-range urban expansion plans threaten the Loxahatchee Slough. A series of land purchases through the Save Our Rivers program, the Palm Beach County Environmentally Sensitive Lands Program will preserve some additional areas within the Loxahatchee Slough system from development and offers the potential of restoration of hydrologic and habitat continuity in the watershed.

RESTORATION OBJECTIVES:

The critical restoration objectives for the Greater Lake Okeechobee Subregion have been identified by the Working Group and are listed as follows:

• Restore more natural hydrologic conditions with appropriate levels, flows, timing and dynamic storage to reduce related ecological stress while managing water resources to meet multipurpose demands.

• Eliminate harmful discharges while restoring natural flows to east and west coast estuaries.

• Protect the ecological function of the Lake Okeechobee littoral zone.

• Develop and implement a management plan for the southern islands in Lake Okeechobee which will maximize natural system benefits.

• Reduce nutrient inputs to natural areas to pre-disturbance levels.

• Improve or maintain water quality necessary for healthy natural system function.

• Manage water and nutrients to sequester in-place Hg.

• Reestablish and maintain recreational and commercial fisheries.

• Eliminate or minimize habitat loss and degradation and restore degraded habitats.

• Restore overdrained and degraded wetlands.

• Eliminate or drastically reduce the presence of exotic plants in the natural areas of the subregion and control their spread.

• Develop sustainable agriculture that controls soil subsidence and takes advantage of natural weather patterns and hydrology.

• Further reduce phosphorus loads from the EAA through reduction in soil oxidation and implementation of BMPs. Construct STAs and use other necessary mechanisms to reach nutrient levels consistent with environmental needs.

RESTORATION PROJECTS