A Proposed Modification to Regulation of Lake OKEECHOBEE1

Conservation Ecology, 2002

Resource management decisions often are based on a combination of scientific and political factors. The interaction of science and politics is not always apparent, which makes the decision-making process appear arbitrary at times. In this paper, we present a case study involving Lake Okeechobee, a key environmental resource in South Florida, USA, to illustrate the role that science played in a high-profile, highly contentious natural resource management decision. At issue was whether or not to lower the water level of Lake Okeechobee. Although scientists believed that a managed recession (drawdown) of water level would benefit the lake ecosystem, risks were present because of possible future water shortages and potential environmental impacts to downstream ecosystems receiving large volumes of nutrient-rich fresh water. Stakeholders were polarized: the agriculture and utility industries favored higher water levels in the lake; recreation users and businesses in the estuaries wanted no or minimal discharge from the lake, regardless of water level; and recreation users and businesses around the lake wanted lower water levels to improve the fishery. Jurisdictional authority in the region allowed the Governing Board of the South Florida Water Management District to take emergency action, if so warranted. Based on information presented by staff scientists, an aggressive plan to release water was approved in April 2000 and releases began immediately. From a hydrological perspective, the managed recession was a success. Lake levels were lowered within the targeted time frame. In addition, water quality conditions improved throughout the lake following the releases, and submerged plants displayed a dramatic recovery. The short-term nature of the releases had no lasting negative impacts on downstream ecosystems. Severe drought conditions developed in the region during and following the recession, however. Severe water use restrictions were implemented for several months. There also were impacts to the local economy around the lake, which depends heavily on recreational fishing; use of boat launch areas was curtailed because of the low water levels in the lake. This case study provides an example of how science was used to justify a controversial decision. Although the environmental basis for the decision was validated, unexpected or unpredictable climatic results led to socioeconomic challenges that offset the environmental successes.

Annals of the American Association of Geographers, 2019

Evaluating the water storage function of Lake Okeechobee can provide important insight into understanding the lake's historical role in attenuating the magnitude and timing of flows (particularly during the wet season) in the Greater Everglades region. This article investigates the predrainage and early postdrainage spatial extent, lake stages, and changes to plant communities. Two periods of time were assessed: predrainage (prior to 1880) and early postdrainage (1880-1945). Analyses were conducted by integrating written historical accounts, lake stages, and hydrographs with a geospatial analysis derived from nautical charts and other historical maps from additional points in time (1913 and 1926). Results indicate that predrainage lake stages were much higher than the current water management regime, but the spatial extent of the lake open water is relatively unchanged. We estimated a reduction in storage volume of Lake Okeechobee from 6,922 million m 3 to 4,347 million m 3 during the early postdrainage period (1880-1945) at high lake stages. This represents a loss in volume of 2,575 million m 3 at a high lake level and of 3,016 million m 3 at a low lake level. The loss in storage volume has changed the historical flow patterns from the Lake Okeechobee region with consequences to downstream watersheds.

2013

Lake Okeechobee, the largest lake in the southeastern United States, is shallow, frequently turbid, eutrophic, and a central component of the hydrology and environment of South Florida. The lake supplies water for agriculture and downstream ecosystems, and provides flood control for surrounding areas. It is also the primary water supply for the Okeechobee Utility Authority and the backup water supply for much of South Florida. Lake Okeechobee is home to migratory water fowl, wading birds, and the federally endangered Everglade snail kite. The lake is also a multi-million dollar recreational and commercial fishery.

Water Resources …, 2008

The management of Lake Okeechobee in Florida has undergone significant changes in the last decade. Socio-political, environmental and demographic factors have driven changes in the environmental and water policy, which in turn have led to wideranging institutional changes and a shift toward multiobjective planning and implementation in the Lake management. This article describes the changes in the philosophy and practice of water resources management in South Florida hydrologic system, of which Lake Okeechobee is a crucial component. The impacts of the changes on management goals and decision processes are illustrated through a case study of the use of climate information in Lake management. The article concludes with a brief examination of the implications of the institutional changes, including greater public participation, for the long-term sustainability of the social-ecological system in South Florida.

Environmental Management, 2013

We considered how Lake Okeechobee, a large shallow lake in Florida, USA, might respond to altered hydrology associated with climate change scenarios in 2060. Water budgets and stage hydrographs were provided from the South Florida Water Management Model, a regional hydrologic model used to develop plans for Everglades restoration. Future scenarios include a 10 % increase or decrease in rainfall (RF) and a calculated increase in evapotranspiration (ET), which is based on a 1.5°C rise in temperature. Increasing RF and ET had counter-balancing effects on the water budget and when changing concurrently did not affect hydrology. In contrast, when RF decreased while ET increased, this resulted in a large change in hydrology. The surface elevation of the lake dropped by more than 2 m under this scenario compared to a future base condition, and extreme low elevation persisted for multiple years. In this declining RF/increasing ET scenario, the littoral and near-shore zones, areas that support emergent and submerged plants, were dry 55 % of the time compared to less than 4 % of the time in the future base run. There also were times when elevation increased as much as 3 m after intense RF events. Overall, these changes in hydrologic conditions would dramatically alter ecosystem services. Uncertainty about responses is highest at the pelagic-littoral interface, in regard to whether an extremely shallow lake could support submerged vascular plants, which are critical to the recreational fishery and for migratory birds. Along with improved regional climate modeling, research in that interface zone is needed to guide the adaptive process of Everglades restoration.

Operating Reservoirs in Changing Conditions, 2006

1994

The South Florida Ecosystem encompasses an area of approximately 28,000 km 2 comprising at least 11 major physiographic provinces, including the Kissimmee River Valley, Lake Okeechobee, the Immokalee Rise, the Big Cypress, the Everglades, Florida Bay, the Atlantic Coastal Ridge, Biscayne Bay, the Florida Keys, the Florida Reef Tract, and nearshore coastal waters. South Florida is a heterogeneous system of wetlands, uplands, coastal areas, and marine areas, dominated by the watersheds of the Kissimmee River, Lake Okeechobee, and the Everglades. Prior to drainage, wetlands dominated the ecosystem, covering most of central and southern Florida. The landscapes included swamp forests; sawgrass plains; mosaics of sawgrass, tree islands, and ponds; marl-forming prairies dominated by periphyton; wet prairies dominated by Eleocharis and Nymphaea; freshwater marshes; saltwater marshes; cypress strands; and a vast lake-river system draining into Lake Okeechobee. Elevated areas that did not flood supported pine flatwoods, pine rocklands, scrub, tropical hardwood hammocks, and xeric hammocks dominated by oaks. The natural seascapes of South Florida consisted of riverine and fringe mangrove forests; beaches and dunes; seagrass beds; intertidal flats; mud banks; hardbottom communities; coral reefs; and open, inshore shallows. All these habitats were interconnected on an extremely low topographic gradient (2.8 cmlkm) with elevations ranging from about 6 m at Lake Okeechobee to below sea level at Florida Bay. The large numbers of diverse biota that these habitats once supported were maintained by the complex annual and long-term hydrologic patterns of the-natural system, as expressed in wet-dry cycles, drying and flooding rates, surface water and water depth patterns, annual hydroperiods, flow volumes, and, at the coast, salinity and mixing patterns. Superimposed over the periodic changes were sporadic events such as storms, fires, and freezes, which helped to establish and maintain habitat heterogeneity. Productivity of the predrainage wetlands of South Florida was dependent on: 6 BACKGROUND Water is life for South Florida's human and natural systems. Clean, abundant water was a fundamental characteristic of the original South Florida System. The increased human population and human activity in South Florida have brought with them not only an increased need for water but also deterioration in water quality and a decrease in water supply. The latter was caused by the loss of dynamic, or short-term, water storage capacity that Flexible and sustained resources are essential to an effective, comprehensive restoration effort. The various involved agencies have unique and complex funding strategies. There is no specific South FlOrida Ecosystem Restoration funding source. Thus, there are critical activities needed at early stages in the restoration process that are being neglected for lack of directed resources. Many who live in South Florida do not realize the benefits they receive continuously from a functioning natural ecosystem and what ecosystem collapse would mean to them. Both tangible and intangible connections between natural and human systems need to be quantified and widely communicated while reinstatement of a sustainable system is still possible. Some obvious examples are the decline of Florida Bay fisheries, the elevated mercury concentrations in fish and alligators in the Everglades, and the drinking water quality problems in South Florida water treatment plants. Issues of agency authority are at times a barrier to focusing efforts at problem sources. Control of harmful non-indigenous plant species is an arena where there are jurisdictional gaps. The many aggressive upland species invading publicly owned natural areas are not included in major control and research initiatives, which appear confined primarily to control of aquatic weeds, Melaleuca, and agricultural pests. Soil subsidence is another arena where there may be jurisdictional gaps. Decision makers and the general public appear not to understand the potential consequences of developing in wetlands. A scientifically based analysis is needed to demonstrate alternative futures under various land and water configurations. Information exchange is a problem, because there is so much information in the hands of myriad sources, including local governments. Potential opportunities need to be explored for configurations of land and water that lead to ecosystem restoration and enhanced quality of life and economic sustainability in human communities. Use of models as technical tools in the restoration effort requires buy-in by all the parties. An objective process is needed for evaluating existing models within the context they are being used and ensuring that necessary improvements are made, while at the same time protecting useful models against possibly one. sided attacks on their credibility. The fact that useful, credible models are available should not preclude the development of new models that can address problems of resolution, scope, and flexibility. Certain key species or communities that might be suitable ecological indicators because of their important roles in the ecosystem or their sensitivity to anthropogenic changes are so poorly studied that they Cannot be used as indicators. Furthermore, lack of knowledge about the response of these species or communities to hydrologic variables may seriously handicap the restoration effort. Critical linkages between subregions are not being adequately addressed within agencies. For instance, Florida Bay is perceived as being in a crisis state, demanding immediate attention, and alteration in freshwater flow is thought to be a major contributor to the decline in this system. Yet the models and supporting measurements and special studies to estimate freshwater inflow to Florida Bay are not being given high priority relative to other issues.

Ecological Engineering, 2019

This is an updated version of a review written by the author in April 2018 at the request of The Friends of the Everglades, an NGO based in Miami, Florida, on a plan developed primarily by the South Florida Water Management District (SFWMD) to mitigate coastal pollution that has resulted from discharges from Lake Okeechobee to the Gulf of Mexico and Atlantic coastline and eventually to “send the water south” to the Florida Everglades instead. This EAA Reservoir project was included by the U.S. Army Corps of Engineers in a 2018 U.S. Congressional bill that was approved. In May 2019, U.S. President Donald Trump pledged to spend $200 million to begin construction of this restoration, three times the amount requested by the state of Florida. While supported with enthusiasm by the Florida state legislature, the SFWMD, and some NGOs such as The Everglades Foundation, a change in leadership in the state of Florida after November 2018 elections and especially in the leadership of the South Florida Water Management District (SFWMD) has led to a renewed public optimism for major improvements in water quality management in south Florida. It is therefore timely for this review of the advantages and shortcomings of this “EAA (Everglades Agricultural Area) Reservoir Plan” to be widely disseminated in an international forum such as Ecological Engineering to encourage discussions among scientists and engineers.

Lake and Reservoir Management

Legally mandated eutrophication restoration goals for Lake Okeechobee (FL) are unachievable, therefore assigning managers a "mission impossible." Since the 1970s, restoration efforts have focused on reducing pelagic total phosphorus (TP) to 40 mg/L. A total daily maximum load (TMDL) of 140 metric tons (t)/yr was adopted by the Florida Department of Environmental Protection in 1999 (effective date 2015) to restore the lake's balance of flora and fauna. Phosphorus (P) loads (1975-2018) averaged 516 t/yr with no significant change over time, yet average TP significantly increased from 51 mg/L (1974-1977) to 146 mg/L (2015-2019). Greater TP values in 2019 were due to Hurricane Irma and an early June storm event. Annual P-loads and pelagic TP were not significantly correlated. Instead, TP was strongly correlated with turbidity (R 2 ¼ 0.85), which is generated by wave-driven resuspension of P-rich unconsolidated sediments. Since 1973, >13,000 t of TP has been added to Okeechobee's sediments that have accumulated over the past century due to the lowering of water levels and the construction of the Herbert Hoover Dike. Prior to settlement, high water levels allowed turbid lake waters to flood large areas of adjacent wetlands, where suspended sediments were removed from the lake. With the minimization of this self-cleansing mechanism after construction of the Herbert Hoover Dike, P-rich fine sediments accumulated, and periodic hurricanes disrupted consolidated sediments. Unconsolidated sediments are easily resuspended into the water column, raising TP. Efforts to reduce Okeechobee's pelagic TP through reductions of P-loads alone will not work due to sediment accumulation and resuspension.

2006

This chapter presents an update on the progress of the implementation of the Long-Term Plan for Achieving Water Quality Goals in the Everglades Protection Area (Long-Term Plan) (Burns and McDonnell, 2003). Because there is overlap between many of the Long-Term Plan projects and other South Florida Water Management District (SFWMD or District) Everglades restoration efforts, the updates for many of the Long-Term Plan projects will appear in other chapters of the 2005 South Florida Environmental Report-Volume I. For example, the Long-Term Plan projects that cover the Everglades Stormwater Program (ESP) basins and source controls will be covered in Chapter 3 of this volume, and the Long-Term Plan projects relating to the Everglades Construction Project (ECP) Stormwater Treatment Areas (STAs) will be covered in Chapter 4 of this volume. For additional reference, Table 8-1 indicates the chapter where each Long-Term Plan project update appears. The long-term Everglades water quality goal is for all discharges to the Everglades Protection Area (EPA) to achieve and maintain water quality standards in the EPA, including compliance with the total phosphorus (TP) criterion established in Rule 62-302.540, Florida Administrative Code (F.A.C.). Substantial progress toward reducing phosphorus levels discharged into the EPA has been made by the State of Florida and other stakeholders. As of April 2004, the Everglades Agricultural Area's (EAA's) Best Management Practices and the Stormwater Treatment Areas combined have removed over 1,730 metric tons of TP that otherwise would have entered the Everglades. Approximately 230 additional metric tons of TP were removed during Water Year 2004 (WY2004) (May 1, 2003 through April 30, 2004), but additional measures are necessary to achieve the Everglades water quality goal. The Long-Term Plan contains activities to achieve that goal, and permits the State of Florida and the District to fulfill their obligations under both the Everglades Forever Act (EFA) [Section 373.4592, Florida Statutes (F.S.)] and the federal Settlement Agreement (Case No. 88-1886-CIV-MORENO). A summarized list and locations of the basins addressed in the Long-Term Plan are presented in Table 8-2 and Figure 8-1, respectively.

2008

2002

SUMMARY This chapter discusses the multidisciplinary approaches currently in place to manage the hydrologic patterns of the Everglades Protection Area (EPA). The primary focus of this chapter is on the hydrologic trends and ecological assessments in the EPA in relation to the 2001 drought. Much attention has been given to the lowest-recorded Lake Okeechobee water levels in Florida history. Low

Lake and Reservoir Management, 2008

Lake Tohopekaliga is a large (surface area 9,800 ha) and shallow (mean depth 2.1 m) natural lake in central Florida. Cultural eutrophication and lake water level stabilization led to accelerated growth of invasive native and non-native aquatic macrophytes, resulting in the buildup of thick deposits of organic matter along the shoreline. Those shoreline areas were often devoid of oxygen, and the muck buildup filled feeding grounds for wading birds and spawning fish. Muck build up has also reduced aesthetics and boat access. To remove organic accumulation, the lake water level was dropped and heavy equipment was used to scrape the plants and dead organic materials from the underlying sand substrates from more than 1,420 ha of the littoral zone. Most of this material was heaped into large piles in shallow parts of the lake to form 29 artificial islands with basal areas from 0.4 to 3.3 ha each. Our study was designed to determine: (1) amount of nutrients stored in islands relative to annual inflows, (2) nutrient release to the lake from the islands, and (3) changes in lake trophic state due to the muck scraping and construction of the islands. The lake enhancement project was completed in late summer 2004, and the average thickness of organic materials in the scrapped areas was reduced from 46 cm to 1.6 cm, improving access and aesthetics tremendously. The islands stored several times the annual inflow of total phosphorus (TP, 3.1 times) and Total Nitrogen (TN, 6.5 times) and thus could potentially affect the lake's trophic state by leaching nutrients. Our study of water quality in the vicinity of the islands indicates that the islands had no statistically significant impact on the water chemistry of the lake through leaching of nutrients. In the 2 years following the muck removal, substantial increases in average TP (39%), chlorophyll (56%), and color (53%) and a decline in dissolved oxygen (−10%) were found in open water stations. An unintended complication to our experimental design was the occurrence of 3 major hurricanes with high winds and heavy rainfalls that passed over the Lake Tohopekaliga area immediately following the muck removal project. To account for the effects of hurricane activity we examined monthly TP, TN, chlorophyll, Secchi depth data, and quarterly color values measured for 55 relatively small (median surface area 33 ha), nearby lakes. Our sample of 55 nearby lakes showed significant increases in TP (8.2%), TN (4.1%), chlorophyll (20.1%), and water color (23.8%), and decreases in Secchi depth (−8.2%) coinciding with the passage of the hurricanes. Additionally, data from a larger control lake (Kissimmee, surface area 19,800 ha) located 10 km south of Lake Tohopekaliga showed a much larger increase in total phosphorus (66%). Therefore, some or possibly all of the differences we measured before and after scraping could have been the result of low quality water (high nutrients and organic color) flushed into the lake following the heavy rains (93 cm in August and September of 2004) accompanying the storms. The effects of muck removal cannot be completely separated from those of hurricanes because they both occurred at the same time. However, aquatic plant (Florida Department of Environmental Protection) and water chemistry (Florida Fish and Wildlife Conservation Commission) data collected after this project was completed show that submersed aquatic macrophytes in Lake Tohopekaliga have returned and total phosphorus and chlorophyll concentrations are down to levels measured prior to muck scraping and hurricane impacts. Thus, the changes in water chemistry caused by muck removal and/or the hurricanes were relatively short lived (approximately 2 years).

Thescientificworldjournal, 2001

In order to reverse the damage to aquatic plant communities caused by multiple years of high water levels in Lake Okeechobee, Florida (U.S.), the Governing Board of the South Florida Water Management District (SFWMD) authorized a managed recession to substantially lower the surface elevation of the lake in spring 2000. The operation was intended to achieve lower water levels for at least 8 weeks during the summer growing season, and was predicted to result in a large-scale recovery of submerged vascular plants. We treated this operation as a whole ecosystem experiment, and assessed ecological responses using data from an existing network of water quality and submerged plant monitoring sites. As a result of large-scale discharges of water from the lake, coupled with losses to evaporation and to water supply deliveries to agriculture and other regional users, the lake surface elevation receded by approximately 1 m between April and June. Water depths in shoreline areas that historically supported submerged plant communities declined from near 1.5 m to below 0.5 m. Low water levels persisted for the entire summer. Despite shallow depths, the initial response (in June 2000) of submerged plants was very limited and water remained highly turbid (due at first to abiotic seston and later to phytoplankton blooms). Turbidity decreased in July and the biomass of plants increased. However, submerged plant biomass did not exceed levels observed during summer 1999 (when water depths were greater) until August. Furthermore, a vascular plant-dominated assemblage (Vallisneria, Potamogeton, and Hydrilla) that occurred in 1999 was replaced with a community of nearly 98% Chara spp. (a macro-alga) in 2000. Hence, the lakes submerged plant community appeared to revert to an earlier successional stage despite what appeared to be better conditions for growth. To explain this unexpected response, we evaluated the impacts that Hurricane Irene may have had on the lake in the previous autumn. In mid-October 1999, this category 1 hurricane passed just to the south of the lake, with wind velocities over the lake surface reaching 90 km h -1 at their peak. Output from a three-dimensional hydrodynamic / sediment transport model indicates that during the storm, current velocities in surface waters of the lake increased from near 5 cm s -1 to as high as 100 cm s -1 . These strong velocities were associated with large-scale uplifting and horizontal transport of fine-grained sediments from the lake bottom. Water quality data collected after the storm confirmed that the hurricane resulted in lake-wide nutrient and suspended solids concentrations far in excess of those previously documented for a 10-year data set. These conditions persisted through the winter months and may have negatively impacted plants that remained in the lake at the end of the 1999 growing season. The results demonstrate that in shallow lakes, unpredictable external forces, such as hurricanes, can play a major role in ecosystem dynamics. In regions where these events are common (e.g., the tropics and subtropics), consideration should be given to how they might affect long-term lake management programs.

2000

This project would not have been possible without the crucial support of many persons in the Florida Department of Environmental Protection (DEP). Mike Scheinkman of DEP was work assignment manager of the project and provided critical guidance and assistance. Jim Hulbert and Ellen McCarron of DEP had the vision to support the first statewide implementation of EPA's lake bioassessment protocols, and Jim Hulbert also designed much of the program. Russel Frydenborg developed the sampling protocols, trained many of DEP's lake biologists, and provided critical assistance for the program. Glenn Griffith and Jim Omernik of USEPA developed the lake regionalization that we relied upon for this project. Bill Beers and Kim Schildt of DEP developed the land use analysis of lake buffer zones. Lou Ley of DEP coordinated data input to the statewide database. Eric Pluchino of DEP volunteered help with lake sampling and taxonomic identification. Finally, the project depended on the DEP lake biologists who sampled hundreds of lakes throughout Florida, developed the data, and prepared reports that formed the basis for these analyses: