This chapter sets the stage for the sixth of this committee’s biennial assessments of restoration progress in the South Florida ecosystem. Background for understanding the project is provided through descriptions of the ecosystem decline, restoration goals, the needs of a restored ecosystem, and the specific activities of the restoration project.
The Everglades once encompassed about 3 million acres of slow-moving water and associated biota that stretched from Lake Okeechobee in the north to the Florida Keys in the south (Figures 1-1a and 2-1a). The conversion of the Everglades wilderness into an area of high agricultural productivity and cities was a dream of 19th-century investors, and projects begun between 1881 and 1894 affected the flow of water in the watershed north of Lake Okeechobee. These early projects included dredging canals in the Kissimmee River Basin and constructing a channel connecting Lake Okeechobee to the Caloosahatchee River and, ultimately, the Gulf of Mexico. By the late 1800s, more than 50,000 acres north and west of the lake had been drained and cleared for agriculture (Grunwald, 2006). In 1907, Governor Napoleon Bonaparte Broward created the Everglades Drainage District to construct a vast array of ditches, canals, dikes, and “improved” channels. By the 1930s, Lake Okeechobee had a second outlet, through the St. Lucie Canal, leading to the Atlantic Ocean, and 440 miles of other canals altered the hydrology of the Everglades (Blake, 1980). After hurricanes in 1926 and 1928 resulted in disastrous flooding from Lake Okeechobee, the U.S. Army Corps of Engineers (USACE) replaced the small berm that bordered the southern edge of the lake with the massive Herbert Hoover Dike, which was eventually expanded in the 1960s to encircle the lake. The hydrologic end-product of these drainage activities was the drastic reduction of water storage
within the system and an increased susceptibility to drought and desiccation in the southern reaches of the Everglades (NRC, 2005).
After further flooding in 1947 and increasing demands for improved agricultural production and flood control for the expanding population centers on the southeast Florida coast, the U.S. Congress authorized the Central and Southern Florida (C&SF) Project. This project provided flood control and urban and agricultural water supply by straightening 103 miles of the meandering Kissimmee River, expanding the Herbert Hoover Dike, constructing a levee along the eastern boundary of the Everglades to prevent flows into the southeastern urban areas, establishing the 700,000-acre Everglades Agricultural Area (EAA) south of Lake Okeechobee, and creating a series of Water Conservation Areas (WCAs) in the remaining space between the lake and Everglades National Park (Light and Dineen, 1994). The eastern levee isolated about 100,000 acres of the Everglades ecosystem, making it available for development (Lord, 1993). In total, urban and agricultural development have reduced the Everglades to about one-half its pre-drainage size (see Figure 1-1b; Davis and Ogden, 1994) and have contaminated its waters with chemicals such as phosphorus, nitrogen,
sulfur, mercury, and pesticides. Associated drainage and flood control structures, including the C&SF Project, have diverted large quantities of water to the coastal areas, thereby reducing the freshwater inflows and natural water storage that defined the ecosystem (see Figure 2-1b).
The profound hydrologic alterations were accompanied by many changes in the biotic communities in the ecosystem, including reductions and changes in the composition, distribution, and abundance of the populations of wading birds. Today, the federal government has listed 78 plant and animal species in South Florida as threatened or endangered, with many more included on state lists. Some distinctive Everglades habitats, such as custard apple forests and peripheral wet prairie, have disappeared altogether, while other habitats are severely reduced in area (Davis and Ogden, 1994; Marshall et al., 2004). Approximately 1 million acres are contaminated with mercury (McPherson and Halley, 1996). Phosphorus from agricultural runoff has impacted water quality in large portions of the Everglades and has been particularly problematic in Lake Okeechobee (Flaig and Reddy, 1995) (see Chapter 3 for a more detailed discussion of phosphorus enrichment in the Everglades). The Caloosahatchee and St. Lucie estuaries, including parts of the Indian River Lagoon, have been greatly altered by high and extremely variable freshwater discharges that bring nutrients and contaminants and disrupt salinity regimes (Doering, 1996; Doering and Chamberlain, 1999).
At least as early as the 1920s, private citizens were calling attention to the degradation of the Florida Everglades (Blake, 1980). However, by the time Marjory Stoneman Douglas’s classic book The Everglades: River of Grass was published in 1947 (the same year that Everglades National Park was dedicated), the South Florida ecosystem had already been altered extensively. Beginning in the 1970s, prompted by concerns about deteriorating conditions in Everglades National Park and other parts of the South Florida ecosystem, the public, as well as the federal and state governments, directed increased attention to the adverse ecological effects of the flood control and irrigation projects (Kiker et al., 2001; Perry, 2004). By the late 1980s it was clear that various minor corrective measures undertaken to remedy the situation were insufficient. As a result, a powerful political consensus developed among federal agencies, state agencies and commissions, Native American tribes, county governments, and conservation organizations that a large restoration effort was needed in the Everglades (Kiker et al., 2001). This recognition culminated in the Comprehensive Everglades Restoration Plan (CERP), which builds on other ongoing restoration activities of the state and federal governments to create one of the most ambitious and extensive restoration efforts in the nation’s history.
RESTORATION GOALS FOR THE EVERGLADES
Several goals have been articulated for the restoration of the South Florida ecosystem, reflecting the various restoration programs. The South Florida Ecosystem Restoration Task Force (hereafter, simply the Task Force), an intergovernmental body established to facilitate coordination in the restoration effort, has three broad strategic goals: (1) “get the water right,” (2) “restore, preserve, and protect natural habitats and species,” and (3) “foster compatibility of the built and natural systems” (SFERTF, 2000). These goals encompass, but are not limited to, the CERP. The Task Force works to coordinate and build consensus among the many non-CERP restoration initiatives that support these broad goals.
The goal of the CERP, as stated in the Water Resources Development Act of 2000 (WRDA 2000), is “restoration, preservation, and protection of the South Florida Ecosystem while providing for other water-related needs of the region, including water supply and flood protection.” The Programmatic Regulations (33 CFR § 385.3) that guide implementation of the CERP further clarify this goal by defining restoration as “the recovery and protection of the South Florida ecosystem so that it once again achieves and sustains the essential hydrological and biological characteristics that defined the undisturbed South Florida ecosystem.” These defining characteristics include a large areal extent of interconnected wetlands, extremely low concentrations of nutrients in freshwater wetlands, sheet flow, healthy and productive estuaries, resilient plant communities, and an abundance of native wetland animals (DOI and USACE, 2005). Although development has permanently reduced the areal extent of the Everglades ecosystem, the CERP hopes to recover many of the Everglades’ original characteristics and natural ecosystem processes. At the same time, the CERP is charged to maintain levels of flood protection (as of 2000) and was designed to provide for other water-related needs, including water supply (DOI and USACE, 2005).
Although the CERP contributes to each of the Task Force’s three goals, it focuses primarily on restoring the hydrologic features of the undeveloped wetlands remaining in the South Florida ecosystem, on the assumption that improvements in ecological conditions will follow. Originally, “getting the water right” had four components—quality, quantity, timing, and distribution. However, the hydrologic properties of flow, encompassing the concepts of direction, velocity, and discharge, have been recognized as an important component of getting the water right that had previously been overlooked (NRC, 2003c; SCT, 2003). Numerous studies have supported the general approach to getting the water right (Davis and Ogden, 1994; NRC, 2005; SSG, 1993), although it is widely recognized that recovery of the native habitats and species in South Florida may require restoration efforts in addition to getting the water right, such as controlling non-native species and reversing the decline in
The goal of ecosystem restoration can seldom be the exact re-creation of some historical or pre-existing state because physical conditions, driving forces, and boundary conditions usually have changed and are not fully recoverable. Rather, restoration is better viewed as the process of assisting the recovery of a degraded ecosystem to the point where it contains sufficient biotic and abiotic resources to continue its functions without further assistance in the form of energy or other resources from humans (NRC, 1996; Society for Ecological Restoration International Science & Policy Working Group, 2004). The term ecosystem rehabilitation may be more appropriate when the objective is to improve conditions in a part of the South Florida ecosystem to at least some minimally acceptable level that allows the restoration of the larger ecosystem to advance. However, flood control remains a critical aspect of the CERP design, and artificial storage will be required to replace the lost natural storage in the system (NRC, 2005). For these and other reasons, even when the CERP is complete, it will require large inputs of energy and human effort to operate and maintain pumps, stormwater treatment areas, canals and levees, and reservoirs, and to continue to manage non-native species. Thus, for the foreseeable future, the CERP does not envision ecosystem restoration or rehabilitation that returns the ecosystem to a state where it can “manage itself.”
Implicit in the understanding of ecosystem restoration is the recognition that natural systems are self-designing and dynamic, and therefore, it is not possible to know in advance exactly what can or will be achieved. Thus, ecosystem restoration is an enterprise with some scientific uncertainty in methods or outcomes that requires continual testing of assumptions as well as monitoring and assessment of progress. This report discusses the challenges to restoration goals arising from major changes that have occurred since the inception of the CERP in 1999 (see Chapter 4). Additional challenges in defining and implementing restoration goals are discussed in the initial National Academies biennial review (NRC, 2007).
What Restoration Requires
Restoring the South Florida ecosystem to a desired ecological landscape requires reestablishment of critical processes that sustain its functioning. Although getting the water right is the oft-stated and immediate goal, the restoration ultimately aims to restore the distinctive characteristics of the historical ecosystem to the remnant Everglades (DOI and USACE, 2005). Getting the water right is a means to that end, not the end itself. The hydrologic and ecologic characteristics of the historical Everglades serve as general restoration goals for a functional
(albeit reduced in size) Everglades ecosystem. The first Committee on Independent Scientific Review of Everglades Restoration Progress review identified five critical components of Everglades restoration (NRC, 2007):
- Enough water storage capacity combined with operations that allow for appropriate volumes of water to support healthy estuaries and the return of sheet flow through the Everglades ecosystem while meeting other demands for water;
- Mechanisms for delivering and distributing the water to the natural system in a way that resembles historical flow patterns, affecting volume, depth, velocity, direction, distribution, and timing of flows;
- Barriers to eastward seepage of water so that higher water levels can be maintained in parts of the Everglades ecosystem without compromising the current levels of flood protection of developed areas as required by the CERP;
- Methods for securing water quality conditions compatible with restoration goals for a natural system that was inherently extremely nutrient poor, particularly with respect to phosphorus; and
- Retention, improvement, and expansion of the full range of habitats by preventing further losses of critical wetland and estuarine habitats, and by protecting lands that could usefully be part of the restored ecosystem.
If these five critical components of restoration are achieved and the difficult problem of invasive species can be managed, then the basic physical, chemical, and biological processes that created the historical Everglades can once again work to create and sustain a functional mosaic of biotic communities that resemble what was distinctive about the historical Everglades.
The history of the Everglades and ongoing global climate change will make replication of the predrainage system impossible. Because of the historical changes that have occurred through engineered structures, urban development, introduced species, and other factors, the paths taken by the ecosystem and its components in response to restoration efforts will not retrace the paths taken to reach current conditions. End results will also often differ from the historical system as climate change and sea level rise, permanently established invasive species, and other factors have moved the ecosystem away from its historical state (Hiers et al., 2012).
Even if the restored system does not exactly replicate the historical system, or reach all the biological, chemical, and physical targets, the reestablishment of natural processes and dynamics should result in a viable and valuable Everglades ecosystem. The central principle of ecosystem management is to provide for the natural processes that historically shaped an ecosystem, because ecosystems are characterized by the processes that regulate them. If the conditions necessary for those processes to operate are met, then recovery of species and communities is
far more likely than if humans attempt to specify and manage every individual constituent and element of the ecological system (NRC, 2007).
Several restoration programs, including the largest of the initiatives, the CERP, are now under way. The CERP often builds upon non-CERP activities (also called “foundation projects”), many of which are essential to the effectiveness of the CERP. The following section provides a brief overview of the CERP and some of the major non-CERP activities.
Comprehensive Everglades Restoration Plan
WRDA 2000 authorized the CERP as the framework for modifying the C&SF Project. Considered a blueprint for the restoration of the South Florida ecosystem, the CERP is led by two organizations with considerable expertise managing the water resources of South Florida—the USACE, which built most of the canals and levees throughout the region, and the South Florida Water Management District (SFWMD), the state agency with primary responsibility for operating and maintaining this complicated water collection and distribution system.
The CERP conceptual plan (USACE and SFWMD, 1999; also called the Yellow Book) proposes major alterations to the C&SF Project in an effort to reverse decades of ecosystem decline. The Yellow Book includes more than 40 major projects consisting of 68 project components to be constructed at a cost of approximately $16.4 billion (estimated in 2014 dollars, including program coordination and monitoring costs; USACE and DOI, 2016; Figure 2-2). Major components of the restoration plan focus on restoring the quantity, quality, timing, and distribution of water for the South Florida ecosystem. The Yellow Book outlines the major CERP components, including the following:
- Conventional surface-water storage reservoirs. The Yellow Book includes plans for approximately 1.5 million acre-feet (AF) of surface storage, located north of Lake Okeechobee, in the St. Lucie and Caloosahatchee basins, in the EAA, and in Palm Beach, Broward, and Miami-Dade counties.
- Aquifer storage and recovery (ASR). The Yellow Book proposes to provide substantial water storage through ASR, a highly engineered approach that would use a large number of wells built around Lake Okeechobee, in Palm Beach County, and in the Caloosahatchee Basin to store water approximately 1,000 feet below ground.
- In-ground reservoirs. The Yellow Book proposes additional water storage in quarries created by rock mining.
- Stormwater treatment areas (STAs). The CERP contains plans for additional constructed wetlands that will treat agricultural and urban runoff water before it enters natural wetlands.1
- Seepage management. The Yellow Book outlines seepage management projects to prevent unwanted loss of water from the remnant Everglades through levees and groundwater flow. The approaches include adding impermeable barriers to the levees, installing pumps near levees to redirect lost water back into the Everglades, and holding water levels higher in undeveloped areas between the Everglades and the developed lands to the east.
- Removing barriers to sheet flow. The CERP includes plans for removing 240 miles of levees and canals, to reestablish shallow sheet flow of water through the Everglades ecosystem.
- Rainfall-driven water management. The Yellow Book includes operational changes in the water delivery schedules to the WCAs and Everglades National Park to mimic more natural patterns of water delivery and flow through the system.
- Water reuse and conservation. To address shortfalls in water supply, the Yellow Book proposes two advanced wastewater treatment plants so that the reclaimed water could be discharged to wetlands along Biscayne Bay or used to recharge the Biscayne aquifer.
The modifications to the C&SF Project embodied in the CERP were originally expected to take more than 3 decades to complete (and will likely now take much longer), and to be effective, they require a clear strategy for managing and coordinating restoration efforts. The Everglades Programmatic Regulations (33 CFR Part 385) state that decisions on CERP implementation are made by the USACE and the SFWMD (or any other local project sponsors), in consultation with the Department of the Interior, the Environmental Protection Agency (EPA),
1 Although some STAs are included among CERP projects, USACE has clarified its policy on federal cost-sharing for water quality features. A memo from the Assistant Secretary of the Army (Civil Works) (USACE, 2007a) states: “Before there can be a Federal interest to cost share a WQ [water quality] improvement feature, the State must be in compliance with WQ standards for the current use of the water to be affected and the work proposed must be deemed essential to the Everglades restoration effort. . . . This determination must be based on some finding other than the project is a part of CERP and generally will aid the restoration effort.” The memo goes on to state, “the Yellow Book specifically envisioned that the State would be responsible for meeting water quality standards.” Therefore, it appears that until the water flowing into the project features meets existing water quality requirements or unless a special exemption is granted for projects deemed “essential to Everglades restoration,” the state is responsible for 100 percent of the costs of CERP water quality project features.
the Department of Commerce, the Miccosukee Tribe of Indians of Florida, the Seminole Tribe of Florida, the Florida Department of Environmental Protection, and other federal, state, and local agencies (33 CFR Part 385).
WRDA 2000 endorses the use of an adaptive management framework for the restoration process, and the Programmatic Regulations formally establish an adaptive management program that will “assess responses of the South Florida ecosystem to implementation of the Plan; . . . [and] seek continuous improvement of the Plan based upon new information resulting from changed or unforeseen circumstances, new scientific and technical information, new or updated modeling; information developed through the assessment principles contained in the Plan; and future authorized changes to the Plan.” An interagency body called Restoration, Coordination, and Verification (RECOVER) has been established to ensure that sound science is used in the restoration. The RECOVER leadership group oversees the monitoring and assessment program that will evaluate the progress of the CERP toward restoring the natural system and will assess the need for changes to the plan through the adaptive management process (see also Chapter 5).
Non-CERP Restoration Activities
When Congress authorized the CERP in WRDA 2000, the SFWMD, the USACE, the National Park Service, and the U.S. Fish and Wildlife Service were already implementing several activities intended to restore key aspects of the Everglades ecosystem. These non-CERP initiatives are critical to the overall restoration progress. In fact, the CERP’s effectiveness was predicated upon the completion of many of these projects, which include Modified Water Deliveries to Everglades National Park (Mod Waters), C-111 South Dade, and state water quality treatment projects (see Box 2-1). Several additional projects are also under way to meet the broad restoration goals for the South Florida ecosystem and associated legislative mandates. They include extensive water quality treatment initiatives and programs to establish best management practices (BMPs) to reduce nutrient loading.
Major Developments and Changing Context Since 2000
Several major program-level developments have occurred since the CERP was launched that have affected the pace and focus of CERP efforts. In 2004, Florida launched Acceler8, a plan to hasten the pace of project implementation that was bogged down by the slow federal planning process (for further discussion of Acceler8, see NRC, 2007). Acceler8 originally included 11 CERP project components and 1 non-CERP project, and although the state was unable
to complete all the original tasks, the program led to increased state investment and expedited project construction timelines for several CERP projects.
Operation of Lake Okeechobee has been modified twice since the CERP was developed in ways that have reduced total storage. In April 2000, the Water Supply and Environment (WSE) regulation schedule was implemented to reduce high water impacts on the lake’s littoral zone and to reduce harmful high discharges to the St. Lucie and Caloosahatchee estuaries. The regulation schedule was changed again in 2008 to reduce the risk of failure of the Herbert Hoover Dike until the USACE could make critical repairs. This resulted in a loss of 564,000 AF of potential storage from the regional system (see Chapter 4).
In the years since the CERP was launched, the state of Florida has increasingly encouraged the use of alternative water supplies—including wastewater, stormwater, and excess surface water—to meet future water demands (e.g., FDEP, 2015). In 2006, the SFWMD passed the Lower East Coast Regional Water Availability Rule, which caps groundwater withdrawals at 2006 levels, requiring urban areas to meet increased demand through a combination of conservation and alternative water supplies. In 2007, the Florida legislature mandated that ocean wastewater discharges in South Florida be eliminated and 60 percent of those discharges be reused by 2025 (Section 403.086, F.S.), representing approximately 180 million gallons per day of new water supply for the Lower
East Coast. The Florida Department of Environmental Protection (2015) recently released a study with a series of recommendations to reduce the barriers to the use of reclaimed water and stormwater to augment water supply and help meet growing urban and industrial water demands. It remains unclear whether or how these new initiatives and mandates will affect the expectations for agricultural and urban water supply from the CERP, particularly since the capture of excess surface water is a key element of the CERP.
In 2008, Governor Charlie Crist announced the planned acquisition of 187,000 acres of agricultural land from the U.S. Sugar Corporation to maximize restoration opportunities for the South Florida ecosystem. The SFWMD subsequently launched the River of Grass public planning process to facilitate agency and stakeholder input on future uses of the new lands for restoration. Phase II of the planning process was halted in May 2010, without completion. In October 2010, the SFWMD closed on the purchase of 26,800 acres of the U.S. Sugar land for approximately $197 million, and in May 2015, the SFWMD governing board terminated the 10-year option to acquire an additional 153,000 additional acres of the U.S. Sugar land.
In 2010, EPA issued its court-ordered Amended Determination, which directed the State of Florida to correct deficiencies in meeting the narrative and numeric nutrient criteria in the Everglades Protection Area. In 2012, the State of Florida launched its Restoration Strategies Regional Water Quality Plan, which was approved by EPA and the Court as an alternative means to address the Amended Determination. The State of Florida is currently in the process of constructing approximately 6,500 acres of new STAs and 116,000 acres of flow equalization basins (see Chapter 3). These water quality treatment improvements are designed so that water leaving the STAs will meet a new water quality-based effluent limit (WQBEL) to comply with the 10-ppb total phosphorus water quality criterion for the Everglades Protection Area by 2025.2
Changing Understanding of Restoration Challenges
Much new knowledge has been gained since the launch of the CERP that provides a new understanding of restoration challenges and opportunities and informs future restoration planning and management. RECOVER (2011a) high-
2 The WQBEL is a numeric discharge limit used to regulate permitted discharges from the STAs so as not to exceed a long-term geometric mean of 10 μg/L within the Everglades Protection Area. This numeric value is translated into a flow-weighted mean (FWM) total phosphorus (TP) concentration and applied to each STA discharge points, which must meet the following: (1) the STAs are in compliance with WQBEL when the TP concentration of STA discharge point does not exceed an annual FWM of 13 μg/L in more than three out of five years, and (2) annual FWM of 19 μg/L in any water year (Leeds, 2014).
lights key areas of knowledge gained, including predrainage hydrology, modeling, and Everglades landscapes. Considering the many advances in knowledge since 1999, climate change and sea level rise are among the most significant. As outlined in NRC (2014), changes in precipitation and evapotranspiration are expected to have substantial impacts on CERP outcomes. Downscaled precipitation projections remain uncertain and range from modest increases to sizeable decreases for South Florida, and research continues locally and nationally to improve these projections. Sea level rise is already affecting the distribution of Everglades habitats and causing coastal flooding in some low-lying urban areas. CERP planners are now evaluating all future restoration benefits in the context of low, medium, and high sea level rise projections, although NRC (2014) noted the need for greater consideration of climate change and sea level rise in CERP project and program planning. See Chapter 4 for additional discussion of the implications of new knowledge of climate change to the CERP.
Since the CERP was developed, the significance of invasive species management on the success of restoration also has been recognized by the South Florida Ecosystem Restoration Task Force and its member agencies.3 Non-native species constitute a substantial proportion of the current biota of the Everglades. The approximately 250 non-native plants species are about 16 percent of the regional flora (see NRC, 2014). Southern Florida has a subtropical climate with habitats that are similar to those from which many of the invaders originate, with relatively few native species in many taxa to compete with introduced ones. Some species, especially of introduced vascular plants and reptiles, have had dramatic effects on the structure and functioning of Everglades ecosystems, and necessitate aggressive management and early detection of new high-risk invaders to ensure that ongoing CERP efforts to “get the water right” allow native species to prosper instead of simply enhancing conditions for invasive species.
FLOODS AND DROUGHTS AND THE LIMITATIONS OF WATER MANAGEMENT INFRASTRUCTURE IN 2015-2016
The 2015-2016 period included both localized droughts in the summer of 2015 that triggered seagrass die-off in Florida Bay and record rainfall the following winter, which led to large releases to the Caloosahatchee and St. Lucie Estuaries, high water conditions in the Water Conservation Areas, and harmful algal blooms during the summer of 2016. Both events highlight the limitations of existing infrastructure and water management options to reduce the adverse impacts of low and high water conditions.
Seagrass Die-offs in Florida Bay
Florida Bay is an important nursery for commercially or recreationally important fish and invertebrate species. The bay, which covers about 850 mi2 (2,200 km2), is shallow (< 9 ft or 3 m) and is divided by mud banks into somewhat isolated basins in the central and eastern parts of the bay (Fourqurean and Robblee, 1999; NRC, 2002a). In the mid- to late 1900s, Florida Bay was characterized as having clear water and dense seagrasss meadows, but in 1987, hypersaline conditions resulting from chronic and acute shortages of freshwater inflows triggered a cascade of ecological effects in the bay. Together with high temperatures, the hypersaline conditions caused hypoxic conditions and high sulfide levels that caused widespread seagrass collapse in the central and western portions of the bay, algal blooms, and increased turbidity (Deis, 2011; Hall et al., 1999) with major effects on commercial and recreational fishing. Although the most acute impacts lasted between 1987 and 1991, the ecosystem was still recovering as of the mid-2000s (J. Fourqurean, FIU, personal communication, 2015). In 2015, a seagrass die-off (Figure 2-3) was again observed in several locations in the bay. The 2015 seagrass die-off was attributed to local rainfall deficits associated with a strong El Niño which, in addition to the chronic shortage of freshwater deliveries, led to increased salinity in the bay (up to 72 practical salinity units [psu] in Garfield Bight, the highest salinity yet recorded in the bay) (NPS, 2016a). By late 2015, the spatial extents of seagrass die-off included areas such as Johnson Key, Rankin Lake, Pelican Key, Dido Key Bank, and Garfield Bight (NPS, 2016a). In the 1980s, the collapse of Florida Bay brought increased scientific, public, and political attention to the conditions of the Greater Everglades ecosystem and support for restoration actions to increase flows to and restore conditions in Everglades National Park and Florida Bay. Twentieth-century water management in South Florida had decreased freshwater inflow to the bay by about 60 percent compared to predrainage conditions, while altering the distribution and timing of that water (Herbert et al., 2011). CERP and non-CERP projects (e.g., C-111 Spreader Canal Western Project, C-111 South Dade), were authorized and constructed to help restore freshwater flows to Taylor Slough and Florida Bay, but as of 2015, flow restoration implementation was insufficient to prevent a recent reoccurrence of seagrass die-off. The status of these and other projects designed to enhance flow to Florida Bay is discussed further in Chapter 3.
By late summer of 2015, the rains came and continued at unusually high amounts well into the winter, returning salinity levels in Florida Bay to normal levels. No major expansion of die-off has been observed in 2016, but new areas with many small die-off patches have been found. Whether these are unusual or simply the result of more-intensive monitoring efforts is not known at present
(D. Rudnick, Everglades National Park, personal communication, 2016). Monitoring of the seagrass and water chemistry in Florida Bay continues (NPS, 2016a).
Extreme High Water in 2016
In contrast to the local drought conditions of 2015, the Everglades ecosystem experienced unseasonably high rainfall and extreme high water levels in early 2016, which caused difficult operational challenges for water managers. The November 2015 through January 2016 period (normally the dry season) was the wettest on record, caused in part by a strong El Niño. Above-average rainfall also fell in May 2016, again raising concerns about high water levels in Lake Okeechobee at what is typically the start of the wet season.
With existing water management infrastructure, there are numerous constraints that limit how water can be stored or discharged under extreme high
water conditions. The CERP and other non-CERP projects help address some, but not all, of these constraints. Currently, high water levels (above 17.25 feet National Geodetic Vertical Datum [NGVD] 1929) cannot be maintained in Lake Okeechobee due to the risk of structural failure of the Herbert Hoover Dike, which is being rehabilitated (USACE, 2008). Inflow capacity to the lake far exceeds the outflow capacity, and water levels can rise quickly to dangerous levels during periods of heavy rain. Therefore, lake levels must be managed carefully to protect public safety. By mid-February 2016, water levels in Lake Okeechobee were reaching dangerously high water levels (above 16 ft NGVD and still rising4), and all existing water storage facilities were at capacity (Staletovich, 2016). To reduce water levels in the lake, water was discharged to the northern estuaries and to other canals at their conveyance capacity, although there was substantial public concern over the high-volume discharges and the accompanying nutrient and sediment loads that are damaging to the estuary ecosystems. Fish kills and algal blooms occurred under similar conditions during 1998 and more recently in 2013 and ultimately occurred during the summer of 2016 (see Box 2-2) (Staletovich, 2016). STA capacity typically limits the amount of water that can be discharged to the Water Conservation Areas, but during much of this period, the water levels in the WCAs were above their regulation schedules and had no capacity to receive more water. Limited capacity existed for discharging water south out of the WCAs based on the conveyance capacities of existing structures, restrictions on the use of the S-12 structures at the southern end of WCA-3A to protect the Cape Sable seaside sparrow, and limitations on water levels in the L-29 canal as part of a phased operations plan for moving water under the new Tamiami Trail 1-mile bridge (J. Mitnik, SFWMD, personal communication, 2016; see also Chapter 3).
Despite these constraints, at the urging of Florida’s governor, water managers took creative actions to limit water releases to the St. Lucie and Caloosahatchee estuaries and help alleviate flooding in the Water Conservation Areas (Staletovich, 2016). Several short-term emergency operation deviations were developed to move water out of the WCAs, including increasing water levels in the L-29 canal to increase the flow under the 1-mile bridge into Northeast Shark River Slough and moving water into Big Cypress National Preserve (SFWMD, 2016a). The limitations of the current water management system compromised the emergency deviation plan as well, as water had to be temporarily released through the S-12 structures to avoid overtopping during the prescribed seasonal closure period for protection of the sparrow (FWS, 2016), and thus ultimately efforts to protect the sparrow failed.
A similar situation occurred in the late 1990s after Hurricane Irene and associated heavy rainfall resulted in extreme high water levels in the lake, leading to a decision by the SFWMD and the USACE to make emergency water releases from the lake in spring 2000. Water releases were made primarily to the St. Lucie and Caloosahatchee estuaries because of conveyance and other constraints to sending water south. Large releases of water from the lake5 lasted for 27 days (Steinman et al., 2002). The decision to make emergency water releases was largely a response to documented damaging effects of high water on the lake’s littoral zone (Havens et al. 2001), and involved a rapid drawdown to allow submerged vegetation to recover (Steinman et al., 2002). Monitoring of the St. Lucie and Caloosahatchee estuaries during the period of emergency water releases indicated immediate negative impacts including increased turbidity and reduced salinity. The St. Lucie estuary recovered quickly after the releases ended, but recovery of the Caloosahatchee estuary was slower due to death of seagrass beds during the event. A cyanobacteria bloom also occurred in the upper St. Lucie estuary, but ended when the releases of lake water stopped (Steinman et al., 2002).
Overall, the high-water events of 2016 provide a harsh reminder that water storage remains inadequate to address devastating high water events in the northern estuaries and illuminate the many constraints that still exist in the system that limit conveyance of water south into the remnant Everglades. Even after 16 years of the CERP, little progress has been made in resolving these well-known constraints. Short-term emergency deviations helped mitigate the impacts, but further progress on CERP and non-CERP projects are needed to provide long-term solutions to such challenges by providing more storage and moving more of the floodwaters south, into and through the Everglades.
The Everglades ecosystem is one of the world’s ecological treasures, but for more than a century the installation of an extensive water control infrastructure has changed the geography of South Florida and facilitated extensive agricultural and urban development. These changes have had profound ancillary effects on regional hydrology, vegetation, and wildlife populations. The CERP, a joint effort led by the state and federal governments and launched in 2000, seeks to reverse the general decline of the ecosystem. Since 2000, the CERP and other major Everglades restoration efforts have faced changing budgets, refinements in scientific understanding, and an evolving legal context, and they continue
5 Typical discharge rates during the emergency event were 2,000 to 2,700 cfs to the St. Lucie estuary and 4,000 to 4,500 cfs to the Caloosahatchee River estuary.
to adapt. The seagrass die-offs in Florida Bay in 2015 and the extreme high-water events and associated algal blooms in 2016, however, provide continued reminders of why substantial restoration progress is needed. Implementation progress is discussed in detail in Chapter 3.