6

A CERP Mid-Course Assessment:
Supporting Sound Decision Making for the Future Everglades

A core theme of the committee’s 2016 report (NASEM, 2016) was the critical need for a forward-looking, systemwide analysis to reexamine restoration outcomes and Comprehensive Everglades Restoration Plan (CERP) goals, objectives, and components in light of recent and potential future changes. The National Academies of Sciences, Engineering, and Medicine (NASEM, 2016) noted several key issues that had emerged since the CERP’s inception in 2000 that were each likely to have significant, systemwide impacts on the outcomes of restoration efforts—advancements in scientific and engineering knowledge related to the understanding of pre-drainage hydrology, climate change and sea-level rise, and the feasibility of storage alternatives.

Just such a need was anticipated in the original CERP Programmatic Regulations (33 CFR §385.31), which call for regular 5-year comprehensive assessments of the program and progress anticipated in light of new information and understandings, termed “CERP updates.” An initial CERP update was completed in 2005 but was not revisited in the decade to follow. NASEM (2016) recommended that an assessment of systemwide CERP benefits be completed in conjunction with program-level adaptive management to ensure that the CERP is based on the latest scientific and engineering knowledge, considers long-term ecosystem needs, addresses potential restoration conflicts, and is robust to changing conditions. Such an effort would better inform current and future project and systemwide program planning efforts and would assure decision makers and the public that, nearly two decades after inception, the CERP is still on track and the best restoration investments are being pursued.

CERP agencies have not acted on the NASEM (2016) recommendation for a CERP systemwide assessment for a variety of reasons, including that (1) an update is not needed because new knowledge has already been incorporated into each individual project planning effort and (2) undertaking a CERP update would require reassigning limited staff and resources, thereby slowing the momentum of

current CERP planning and implementation efforts. This committee is specifically charged to report to Congress not only on progress made but also on scientific and engineering issues that may impact progress (see task in Chapter 1). The committee remains unconvinced that the current, individual, project-level planning approach is an effective means of reassessing the systemwide, scientific-guiding vision for restoration in light of the extended expected time frame for completing the CERP, changing system conditions, and the evolving understanding of the future Everglades ecosystem. As discussed in Chapter 3, no recent individual project planning effort captures the systemwide outcomes of the CERP projects concurrently in planning, and most projects have failed to assess project performance under changing future climate conditions.

It is critically important that the CERP be robust across a large range of temperature, rainfall, sea level, and population regimes that may drive the system as restoration is completed. The original CERP was formulated based on a pre-drainage vision of the historical Everglades and the assumption that rainfall and temperature time series observed during the 1965-1999 period captured the full range of variability that would have been observed under pre-drainage conditions as well as that expected throughout the 21st century. There is now ample evidence that rainfall and temperature distributions in South Florida historically have exhibited multidecadal variations outside the 1965-1999 (or updated 1965-2005) period of record (Enfield et al., 2001; SFWMD, 2011). There is general consensus among climate projections that average temperatures in South Florida will increase over time because of increases in atmospheric greenhouse gases, but considerable uncertainty about future rainfall patterns remains (Carter et al., 2014; Dessalegne et al., 2016; Irizarry et al., 2013; Misra and DiNapoli, 2013; Misra et al., 2012a). There is compelling recent evidence that sea-level rise in South Florida is accelerating and expected to continue in the future (NOAA, 2017). These changes will have profound impacts on the South Florida ecosystem and the ability to provide flood protection and meet the water and recreational demands of a growing population.

Florida continues to be one of the fasting growing states, and it has recently passed New York as the third most populous state. Florida’s population was approximately 16 million when the Yellow Book was completed; it is projected to grow to approximately 21.5 million by 2020 and to more than 26 million by 2040 (Rayer and Wang, 2018). Growth at this rate (nearly 700 people per day) will continue to exert development pressures in South Florida. Volk et al. (2017) project that, at current trends, total developed land in Florida could increase from 6.4 million acres in 2010 to 11.6 million acres in 2070, representing an additional conversion of approximately 14 percent of the total land area in Florida. Future population growth and development has important implications for land and water use and will add to the challenges associated with flood management and water quality.

The committee is sympathetic to the concerns about the opportunity costs associated with reassigning limited staff and resources. NASEM (2016) was complimentary of the pace of restoration and tried to make clear that the recommendation for a systemwide CERP assessment was neither a call for “pencils down” nor for an overhaul of the CERP itself. The committee remains impressed by, and supportive of, the current pace of construction and project planning efforts and expects the agencies to continue CERP implementation efforts while a systemwide CERP assessment is pursued. By mid-2019, tentatively selected plans will have been developed for all of the major central CERP storage projects east, west, south, and north of Lake Okeechobee, with the exception of the Lake Belt in-ground reservoirs. Now that the vision for CERP storage is largely developed and that CERP authorized and soon-to-be-authorized projects will require decades to construct at current funding levels, the time is right to undertake a mid-course assessment.

The committee understands that a mid-course assessment of the CERP might provide information that could motivate a significant recalibration of the original restoration goals. This evolution of the CERP is exactly what was envisioned when the CERP was launched within an adaptive management framework. The mid-course assessment could inform optimal final designs and integration of the individual projects. A systemwide assessment is also essential to ensure that the program-level adaptive management uncertainties that RECOVER identified as “showstoppers” (RECOVER, 2015) are addressed in a timely way, that the CERP is designed for expected future conditions, and that critical transitions can be anticipated, planned for, and more effectively managed. Such an assessment could also inform potentially complementary efforts such as the Southeast Coastal Assessment¹ focused on sea-level rise and coastal vulnerability.

The Everglades of 2050 and beyond will differ from what was envisioned at the time of the Yellow Book. Thus, despite the expressed agency concerns, this committee remains fully supportive of the NASEM (2016) recommendations and the importance of forward-looking program-level analysis that incorporates the latest socioeconomic, scientific, and engineering information, while considering uncertainties about future conditions. The committee notes that even a $10 million investment in such assessment would represent only 0.05 percent of what is likely to be at least a $20 billion restoration effort. This outlay would seem prudent, to ensure that the guiding programmatic vision for restoration as well as future project planning effectively incorporates current knowledge and changing system conditions. This systemwide analysis would also assure the public that scarce public funds are being invested in a manner that maximizes future restoration benefits.

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¹ See http://www.sad.usace.army.mil/SCA/.

In the balance of this chapter, the committee presents new information on sea-level rise and storage that further underscores the need for systemwide analysis; provides guidance on the types of systemwide analysis envisioned for a mid-course assessment; identifies critical research needs to better support CERP planning and implementation in light of future stressors; and suggests programmatic changes that could provide for more effective integration and use of science to inform decision making.

UNDERSTANDING THE CHANGES AFFECTING THE CERP

The Everglades ecosystem has changed dramatically in the last 100 years. While restoration efforts seek to regain characteristics of the historic Everglades ecosystem and support productive fish and wildlife habitat, external drivers such as climate change, species invasions, sea-level rise, land-use changes, and water use influence the ability to achieve this outcome. These internal and external forces on South Florida lead to an ever-changing mosaic of human and natural system elements that impact the outcomes of the CERP. This section presents recent information on two areas of change affecting the CERP—climate change and advances in understanding CERP storage—and their potential implications to restoration planning.

Understanding Climate Change and Sea Level Rise

Many aspects of global climate are changing (USGCRP, 2017) and have implications for the South Florida ecosystem, including changes in surface, atmospheric, and oceanic temperatures; rising sea levels; and ocean acidification. Past Committee on Independent Scientific Review of Everglades Restoration Progress (CISRERP) reports have discussed the possible effects of changes in precipitation (including interannual and seasonal variability) and increasing evapotranspiration on Everglades water budgets (NASEM, 2016; NRC, 2014). This section focuses on new understanding of the implications of sea-level rise on restoration outcomes, based largely on new information since the publication of NASEM (2016). One of the most prominent features of South Florida, and one of its key vulnerabilities in the face of continued sea-level rise, is its 3,400 mi² (8,750 km²) of land area situated below 5 ft (1.5 m) elevation (Titus and Richman, 2001). Sea-level change can cause a number of impacts in coastal and estuarine zones, including inundation or exposure of low-lying coastal areas, changes in storm and flood damages, shifts in extent and distribution of wetlands and other coastal habitats, changes to groundwater levels, and alterations to salinity intrusion into estuaries and groundwater systems (CCSP, 2009).

Rates of sea-level rise have been accelerating recently, from a long-term global mean of 1.5-1.9 mm/yr (1920-2016) to 3.3±0.4 mm/yr (1993-2016). Higher acceleration rates have been recorded in Florida, with long-term rates of 2.4±0.1 (1920-2016) increasing to 7.6±1.3 mm/yr (2000-2016) as observed in Key West (Valle-Levinson et al., 2017). The Southeast Florida Climate Compact (2015) developed unified sea level–rise projections (Figure 6-1), ranging from a scenario of 2.6 ft (0.8 m) by 2100 (the IPCC [2014] median scenario) to 6.8 ft (2 m) by 2100 (NOAA [2014] “high risk” estimate). Incorporation of updated sea-level rise considerations into large-scale ecosystem restoration planning could have substantial implications for planned restoration actions. For example, using updated sea-level rise scenarios in the 2017 Louisiana Coastal Master Plan, compared to the 2012 plan, resulted in dramatically different predictions

of the state of the future coastal landscape and the magnitude of future coastal storm damages (CPRA, 2012, 2017). The California Ocean Protection Council has recently updated guidance for incorporating sea-level rise projections into planning, design, construction, and other decisions (COPC, 2018).

Sea-level rise interacts with other effects of the changing climate including freshwater availability, increasing temperatures, and acidification. Such future changes challenge both the human system and the natural system. The following sections present three examples of how sea-level change and other climate factors can result in transitions within the natural system that may influence CERP outcomes, focusing on effects on wetland peat, northern estuaries, and Florida Bay. How the effects of sea-level rise interact with restoration actions and other system changes has important implications for the future of the ecosystem.

Sea-Level Rise Effects on Wetland Peat

The degree to which sea-level rise results in wetland loss is a complex but critically important issue for South Florida and, more broadly, coastal wetlands globally. The coastal wetland landscape can respond to sea-level rise in three potential ways: (1) peat and sediment accretion that allows coastal wetlands to keep pace with sea-level rise, (2) submergence with landward migration of coastal vegetation and wetland habitat, or (3) submergence and loss of wetland ecosystem habitat, without habitat migration (Chambers et al., 2015). A critical question for the CERP is whether, and for how long, restoration of freshwater flows can mitigate salinity incursion related to sea-level rise and associated peat collapse and can facilitate a landward migration of coastal mangroves to counteract the effects of sea-level rise.

The response of coastal wetlands to sea-level rise depends on a number of counteracting factors. Accretion can occur by the accumulation of mineral sediments and organic matter (Day et al., 2000). The importance of these soil components varies among wetland types and with their proximity to sources of sediment. With sea-level rise, increased frequency and depth of tidal inundation could potentially increase transport of mineral matter to fringe mangroves. The degree to which mineral sediments are deposited in wetlands decreases with distance from the coast or freshwater inflows that are sources of sediment. Sometimes more important than regular tidal or riverine supply of sediment are the episodic inputs from hurricanes. For example, in 2005, sediment deposition to Shark River Slough from Hurricane Wilma was 0.5-4.5 cm, many times greater than annual accretion rates (Castañeda-Moya et al., 2010). For large areas of the coastal Everglades, however, sediment supply is relatively low, so organic matter dynamics largely drive rates of accretion (Chambers et al., 2015). Vertical accre-

tion of organic matter is the net response of above-ground and below-ground plant production, decomposition, inputs of sediment-bound organic matter deposited on the wetland surface, and changes in soil and root bulk density.

A meta-analysis of global data for mangroves indicated that 80 percent were accreting at a rate equal to or exceeding sea-level rise (Alongi, 2008). This pattern is consistent with research findings from the coastal fringe mangroves of Shark River Slough, where rates of accretion from 1924 to 2009 (2.5-3.6 mm/yr) exceed long-term rates of sea-level rise (2.2 mm/yr) (Smoak et al., 2013), but probably not the recent increases to 7.6±1.3 mm/yr (2000-2016) as observed in Key West. However, there is likely considerable spatial variability in landscape response to sea-level rise.

The dynamics of processes that accelerate or retard vertical accretion of organic matter in the coastal Everglades under changing conditions remain incompletely understood and potentially involve a host of mechanisms. For example, increases in tidal inundation and salinity penetration could promote accretion when salt stress reduces microbial action and reducing conditions decrease aerobic decomposition (Chambers et al., 2013, 2014). In addition, because the Everglades is phosphorus-limited, increased supply of phosphorus from Florida Bay associated with sea-level rise and coastal storm surge events could stimulate plant and periphyton production and therefore the accumulation of soil organic matter (Childers et al., 2006; Rivera-Monroy et al., 2007). On the other hand, increases in salinity could facilitate the net loss of soil organic matter through several possible mechanisms. Enhanced decomposition of soil organic matter can occur through an increased supply of the terminal electron acceptor sulfate from sea water, which inhibits methanogenesis and/or shifts the dominant pathway of decomposition toward sulfate reduction (Chambers et al., 2011; Neubauer et al., 2013). Additionally, salt or sulfide generated through enhanced sulfate reduction may cause stress to vegetation, which diminishes above-ground and below-ground production (Batzer and Shartiz, 2006; Castañeda-Moya et al., 2011, 2013; Troxler et al., 2013). Of particular concern for Everglades restoration, saltwater intrusion and increased inundation can cause plant mortality and the collapse of root structures, resulting in subsidence and greatly diminishing the integrity of peat soils. Investigators have also reported decreases in the bulk density of peat soils (Chambers et al., 2014) or loss of root turgor (DeLaune et al., 1994) associated with saltwater inundation, which can contribute to the “collapse” of the peat soils into open water with the sudden loss of elevation and death of wetlands plants. Herbert et al. (2015) describe this as an alternative stable state—freshwater/brackish communities die back, roots die, and there is the structural collapse of peat to open water before saltwater vegetation can reestablish.

The low gradients of much of the South Florida coast enable landward mangrove migration in response to sea-level rise more than in many other coastal areas (Spalding et al., 2014). Ideally during sea-level rise, as salinity penetrates further inland, up-slope freshwater marshes give way to mangroves. Work by Ross et al. (2000) has shown a 50-year vegetation composition shift in the marsh areas of the Southeast Saline Everglades with sea-level rise. This increase in salt-tolerant species such as red mangrove shows that gradual shift can occur in response to modest rates of sea-level rise. However, if increased salinity due to sea-level rise or storm surges impairs salt-intolerant vegetation and compromises the integrity of soil at a rate that exceeds the ability of salt-tolerant vegetation to occupy this space, then peat collapse and ponding can occur in the freshwater wetlands (Chambers et al., 2015; Wanless and Vlaswinkel, 2005).

There is evidence of peat collapse in sawgrass wetlands in South Florida where increased salinity due to sea-level rise or storm surge stresses freshwater vegetation at the upper edge of the coastal ecotone (Figure 6-2). Ongoing experimental studies in Everglades National Park and in controlled mesocosms (Figure 6-3) show the combined influence of salt addition and hydroperiod affect plant production, net ecosystem exchange, and porewater chemistry—all influencing the carbon balance and, ultimately, the peat soil stability of these ecosystems (Mazzei et al., 2018; Wilson et al., 2018; T. Troxler, FIU, personal communication, 2018). Understanding the rates at which these processes occur and key thresholds of salinity and hydroperiod is crucial to predicting future conditions in South Florida. Unless salt-tolerant vegetation can migrate to stabilize these zones, without roots to maintain soil structure and limited carbon production coupled with accelerated decomposition, organic peat collapses and becomes transformed into ponded areas (Figure 6-2). Once ponding occurs, it may be difficult for mangroves to reclaim these areas if the water level becomes too deep to allow for colonization of mangrove propagules or limits dispersal mechanisms. Planting of mangrove propagules to accelerate colonization or to compensate for limited dispersal opportunities in existing vegetation could be warranted.

Freshwater withdrawals or seepage from the remnant Everglades will likely accelerate the potential for peat collapse due to salinity incursion, while increased freshwater deliveries may be able to offset the effects. Meeder et al. (2017) found that during the past century sea-level rise was accompanied by saltwater encroachment, which was controlled by the elevation of high tide and varied widely among the five watersheds studied because of differences in freshwater discharge. In only one of the watersheds was freshwater supply adequate to maintain a plant community resulting in a more rapid rate of sediment accumulation than the other sites. Under diminishing freshwater discharges

and increasing sea-level rise, Meeder et al. (2017) see little hope to mitigate loss of the Southeast Saline Everglades over the long term. Recent work by Dessu et al. (2018) in Shark River Slough found rising magnitude, frequency, and duration of salinity in the coastal sites, as well as seasonal patterns with greater salinity during the dry season. The study points to the need for increasing flows in Shark River Slough, with particular attention during the dry season to reduce salinity intrusion and mitigate peat collapse. It is not clear, however, how long

restoration actions that increase flow will be able to mitigate against salinity intrusion and peat collapse as seas continue to rise. As sea level continues to rise in South Florida, its threat to coastal wetlands becomes more profound. Tools such as the Marsh to Ocean Index (Park et al., 2017) may be useful to represent large-scale patterns of change, but management measures must be grounded in the processes of ecosystem change. Interim and overall restoration goals should reflect what can reasonably be accomplished in the face of these larger regional changes.

Sea-Level Rise and Estuary Restoration Goals

Certain expectations about coastal ecosystem restoration for estuarine fauna may require modification as sea-level rise results in salinity that exceeds the tolerance of some estuarine organisms. At certain locations, it may not be possible to combat high salinity with increased freshwater flow from CERP projects.

Oyster reef restoration serves as an example. One goal of the CERP is to enhance the spatial extent of oyster reefs in the Caloosahatchee Estuary, St. Lucie Estuary, Loxahatchee Estuary, and Lake Worth Lagoon. Oyster reefs provide essential habitat for fish, crustaceans, mollusks, worms, and other biota (Volety et al., 2009). Oysters also filter particles from the water and can have a positive influence on water quality (Coen et al., 1999). One goal of the CERP is to reduce the occurrence of prolonged low-salinity events in estuaries, caused by large freshwater discharges, because past events have killed entire oyster populations (Volety and Tolley, 2005; Volety et al., 2009). However, despite projections, the effects of sea-level rise on northern estuary oyster populations or restoration outcomes have not been adequately examined.

Effects of high salinity have recently been studied in another Florida estuary—the Apalachicola (Camp et al., 2015; Huang et al., 2015). During low rainfall periods, future salinity is projected to be more favorable for marine predators and pathogens of oysters, including worms, sponges, gastropods, and internal unicellular parasites (Camp et al., 2015).

The CERP Monitoring and Assessment Program (RECOVER, 2009) includes oyster monitoring in locations that are likely to have oceanic salinity levels and therefore adverse conditions for oysters at the projected 2060 sea level. Particularly at risk are the Tarpon Bay and Bird Island sites in the Caloosahatchee Estuary (Figure 6-4), sampling sites 1-3 in the St. Lucie Estuary, and the entire Lake Worth Lagoon (Figure 6-5). In contrast, increased salinity might counterbalance effects of freshwater runoff in the north and south forks of the St. Lucie Estuary, as well as sites farther up the river in the Caloosahatchee, and thereby create conditions more favorable to oyster growth.

Sea-level rise will affect the ability of certain locations in the South Florida ecosystem to continue to support oyster reefs. Analysis and assessment are needed to predict the magnitude of effects, and the results should be used to inform expectations regarding oyster growth and survival under restoration conditions. In certain places, such as the Lake Worth Lagoon and the main bays of the St. Lucie and Caloosahatchee Estuaries, it may be unrealistic to set specific goals for any oyster reefs in future decades, regardless of what is done to restore freshwater flow. In the Lake Worth Lagoon, there is no place for oysters to migrate when salinity becomes too high to allow them to survive. In other places, such as the St. Lucie Estuary, oysters might migrate upstream with rising estuarine salinity, assuming that there is suitable substrate and a source of larvae. CERP agencies should consider whether long-term monitoring locations should be changed over time so that the data reflect the health of reefs, wherever they occur, in any given decade.

Florida Bay Restoration and Climate Change

Florida Bay, at the southern end of the Everglades, is a large (850 mi² [2,200 km²]) semi-enclosed shallow embayment internally divided by a series of carbonate mudbanks. These banks restrict ocean flushing and create a series of basins with variable residence time, salinity, and biogeochemical character. The shallow depth, averaging about 3 ft, enables light penetration to support extensive seagrass beds. Evidence suggests that South Florida estuarine geology and biota are sensitive to changes in climate, with ecological regime shifts across Florida Bay and Biscayne Bay in the mid-1950s and early-1960s and across the

southwest coastal margin in the 1980s (Wachnicka and Wingard, 2015; Wingard et al., 2017).

Given that the freshwater budget of Florida Bay is dominated by exchanges with the atmosphere rather than inputs from runoff (Nuttle et al., 2000), there is potential for future changes in evaporation or precipitation to influence salinity and thus ecological change. It is hypothesized that the combined effect of increased temperature and salinity caused the seagrass die-off and subsequent phytoplankton blooms in the 1980s and early 1990s (Koch et al., 2007). Higher temperatures and potential increased risk of long-term drought associated with climate change could pose additional future risks to Florida Bay. However, such changes due to climate should be considered in the light of sea-level rise, which may increase oceanic connectivity if mudbank elevation becomes relatively lower, increasing flushing and potentially mitigating stress to seagrasses (Koch et al., 2015). Future changes in bay functioning with sea-level rise and climate change are likely to vary across the bay because of the differential ability of mudbanks to adjust to changing conditions (Wanless and Taggett, 1989) and interactions with localized inflows from, for example, Taylor Slough.

Climate change studies of Florida Bay habitat suitability for fishes and invertebrates, considering only salinity and temperature variables, found that “the estuarine fauna of Florida Bay may not be as vulnerable to climate change as other components of the ecosystem” (Kearney et al., 2015). The study did show that “temperature increases alone negatively affected the availability of optimal habitat for all species, except that of juvenile spotted seatrout,” but the habitat suitability approach does not consider movement of species to areas with better conditions (which could be easier if mudbanks become relatively lower due to sea-level rise). Kearney et al. (2015) acknowledged that their study does not consider the broader ecosystem effects of climate change on Florida Bay. Using models that are limited in their ability to encompass the complex system dynamics may give a false sense of security regarding future change.

These studies highlight the potential sensitivities of Florida Bay to climate change, sea-level rise, and other factors, such as the rates of carbonate accretion in the mudbanks relative to sea-level rise. The potential geomorphic change influencing bay connectivity needs to be better understood to grasp the interacting implications of climate change and sea-level rise for the effectiveness of CERP-planned actions. Such analysis should be conducted with a system-level view, accounting for potential changes in Florida Bay inflows under a range of future climate conditions to understand the capacity of the CERP to improve the resilience of the Southern Estuaries.

Understanding Changes in CERP Storage

The key to improving the condition of the South Florida estuaries and remnant Everglades ecosystem is creation of storage and conveyance projects that both reduce the amount of water lost to diversions and facilitate temporal and spatial patterns of releases that more closely resemble the pre-drainage system. The CERP, as authorized by Congress in 2000, included several conventional surface reservoirs totaling more than 1 million acre-feet (AF) of capacity, three in-ground reservoirs with more than 300,000 AF, and 333 aquifer storage and retrieval (ASR) wells with an effective capacity of more than 4 million AF (see Table 6-1).

Projects originally included in the CERP required more detailed investigations about their feasibility and design, as well as authorization and appropriations by Congress prior to initiation of construction. During the time it took to undergo those processes, certain CERP projects were substantially reduced in magnitude (Table 6-1). For example, storage north of Lake Okeechobee has been reduced from 200,000 AF of above-ground storage and 200 ASR wells to a 43,000 AF reservoir and 80 ASR wells (USACE and SFWMD, 2018c). The Regional ASR Study (USACE and SFWMD, 2015b), a large-scale pilot study, concluded that only approximately 131 wells could be constructed without impacting the water supply of other users. Reduction of ASR storage capacity in the CERP by two-thirds would reduce all planned storage in CERP by about 50 percent. Plans now include a 240,000 AF reservoir in the Central Everglades Planning Project for the EAA Storage Reservoir (SFWMD, 2018a). The feasibility of two in-ground reservoirs near Everglades National Park, the North and Central Lake Belt Projects that would have added approximately 280,000 AF of storage, has also been questioned, and very little, if any, progress has been made to resolve uncertainty about the Lake Belt reservoirs.

As the largest surface-water storage component in the South Florida ecosystem, Lake Okeechobee is a critical component of regional storage. NASEM (2016) noted that changes in the Lake Okeechobee operating schedule to protect the Herbert Hoover Dike during repairs have dramatically reduced regional storage (as much as 480,000 to 800,000 AF) compared to the original CERP planning assumptions. The agencies plan to revisit the operating policy for Lake Okeechobee (currently scheduled for 2019), but it is not known what portion, if any, of that lost storage will be regained by the adoption of a new schedule, which will also consider adverse effects on increased water levels on the lake ecosystem (see Chapter 5).

Overall, these represent substantial reductions in storage compared to that proposed in the CERP, but the implications to CERP outcomes systemwide has not been examined. Recent sensitivity modeling for the EAA Storage Reservoir

TABLE 6-1 Proposed and Updated Capacities of Storage Components of the Restoration Plan

^a Updated capacity based on difference between an assumed low level of 9 ft and the highest stage in the upper band (17.25 ft for Lake Okeechobee Regulation Schedule (LORS) 2008 and 18.5 ft for Water Supply and Environment [WSE]), based on calculator in http://www.sfwmd.gov/gisapps/losac/sfwmd.asp based on the polynomial model. This capacity may change based on a planned update to the LORS.

^b Based on tentatively selected plan for the Lake Okeechobee Watershed Restoration Project; planning process ongoing.

^c Includes C-23, C-24, C-25, and St. Lucie North and South Fork reservoirs and natural storage areas. Although the storage capacity decreased significantly between the original CERP framework and the final Indian River Lagoon South project implementation report modeling analyses showed that the CERP objectives for the IRL-S project could be reached with substantially less storage.

^d Includes EAA Reservoir and A-1 FEB, which was constructed for Restoration Strategies.

^e An FEB is operated with the primary objective to optimize performance of the STAs (e.g., reduce excessive loading and periods of drydown) rather than to optimize the quantity or timing of water flow to the natural system. Therefore, the hydrologic benefits may be less than other storage features, depending on their operational plans and objectives.

^f The Site 1 Impoundment plan would provide 13,280 AF if constructed, but the SFWMD) has proposed not completing the reservoir.

^gThe project delivery team determined this project to be infeasible.

^h Land sold before it could be acquired. Remaining project elements completed outside of the CERP.

ⁱ Maximum annual storage determined by maximum annual inflows minus maximum annual outflows, over the period of record. Eighty wells are proposed for the Lake Okeechobee Watershed Project, but the maximum storage provided by these wells was not available.

SOURCES: USACE and SFWMD (1999, 2004b, 2010, 2014) and NRC (2005).

as part of the CEPP post-authorization change report (see Chapter 3) suggests that less total storage may be needed than originally envisioned in the CERP to achieve the original objectives for average annual flow into the Everglades from the northern boundary and for reductions in high water discharges from Lake Okeechobee to the Northern Estuaries (SFWMD, 2018a). This effort highlights the importance of analyzing the combined effects of all projects, informed by improved modeling tools and operational strategies, to understand the systemwide outcomes from authorized and planned CERP projects. By the end of 2019, the planning for most major storage components will be complete, with only Lake Okeechobee Regulation and the Lake Belt projects unresolved.

SPECIFIC ANALYSES NEEDED FOR THE MID-COURSE ASSESSMENT

The committee has identified the basic attributes of a systemwide modeling analysis that would support a useful mid-course assessment of CERP outcomes, given new information and changing conditions. The assessment should look into the future, beyond completion of the CERP, when sea level and temperatures will be higher, rainfall may be more variable, saltwater will have intruded farther into coastal aquifers, and freshwater demand may be greater. Ideally, the restored system should be resilient to stresses expected to arise by 2050 and for the remainder of the 21st century. The mid-course assessment should leverage new and updated hydrologic and ecological models and improved climate-

model and sea-level projections that reflect knowledge and data accumulated since the CERP was authorized nearly 20 years ago. The update should also account for new information about CERP project feasibility, operations, and performance. The assessment should be integrative, including major CERP and non-CERP projects and treating them in a coupled, rather than independent, fashion. This integration is essential to examine effects of hydrologic and water quality interconnectedness in shaping Everglades-wide responses in the context of 21st-century conditions.

An assessment that incorporates a few of these basic attributes is in the planning phase. The RECOVER Five-Year Plan includes analysis to support the revision of the existing CERP Interim Goals and Interim Targets (RECOVER, 2005). These will be model-derived quantifications of expected ecological changes or other water-related services (e.g., water supply), based on projections of CERP implementation at future time intervals. RECOVER has gained approval for two sets of hydrologic and ecological modeling runs. The first set will include those projects that, according to the 2016 Integrated Delivery Schedule (see Chapter 3), have been authorized and are scheduled for completion by 2026. The second set will include all authorized projects scheduled for completion by 2030. All totaled, 30 projects are tentatively planned for inclusion in these model runs (Table 6-2). These two runs will be compared against a “current conditions base.” The RECOVER analysis takes advantage of an impressive array of existing models. The South Florida Water Management Model (SFWMM) and the Regional Simulation Model (RSM) are among the models available to simulate water levels and flows. These hydrologic models provide the input data for ecological models capable of simulating vegetation in estuaries, Lake Okeechobee, and Everglades wetlands; aquatic fauna populations; and wading-bird nesting patterns.

This modeling effort represents a step toward a systemwide assessment and should inform an important and overdue update for the Interim Goals and Interim Targets. However, it falls short of what is needed for the mid-course assessment in several key respects. Hydrologic models for the RECOVER update will be forced by rainfall, evapotranspiration, and boundary conditions for a 1965-2005 period of record (W. Wilcox, SFWMD, personal communication, 2018). Although an important part of the analysis, use of the historical period of record alone to drive the hydrologic models is insufficient because there is no accounting for interactions among multidecadal and interannual climate variability, or changes in sea level and climate, that will manifest through the operational lifetimes of the restoration infrastructure. A suitably comprehensive assessment should, in addition to considering historic climate, consider a range of sea-level rise, temperature, and precipitation scenarios for the near term (e.g., 2020-2050), as major projects are completed, and the far term (e.g., 2050-2080),

TABLE 6-2 Potential Projects for Recover Five-Year Plan Modeling

SOURCE: A. McLean, NPS, personal communication, 2018; D. Crawford, USACE, personal communication, 2018.

after these projects are operational and as the ecosystem responds to the restoration measures, sea-level rise, and climate change. This analysis could draw from significant efforts conducted outside of the CERP regarding climate-change impacts on South Florida’s water resources, stormwater, and flood-management infrastructure (e.g., Dessalegne et al., 2016; Havens and Steinman, 2015; Irizarry et al., 2013; Nungesser et al., 2015; Obeysekera, 2013; Obeysekera et al., 2015; Park et al., 2017; Salas et al., 2018).

Another shortcoming of the RECOVER analysis lies in its restrictive focus on those CERP projects that are currently authorized. Consequently, it excludes assessment of potential benefits of major CERP projects that are now in the late stages of planning, such as the Lake Okeechobee Watershed Restoration Project and the Western Everglades Restoration Project as well as the recently authorized EAA Storage Reservoir Project. These projects will affect a large portion of the Everglades footprint. A comprehensive mid-course assessment should, at the outset, consider authorized projects and then be extended to consider projects in

planning. It should also evaluate a range of possible Lake Okeechobee regulation schedules, beyond LORS 2008 and the prior WSE regulation schedules. Although the Lake Okeechobee regulation schedule is not slated for revision until 2022, this broader approach to a CERP mid-course assessment would shed light on how changed lake storage interacts with other projects and influences restoration outcomes.

Modeling for a mid-course, systemwide assessment should explore the near-term (2020-2050) and far-term (2050-2080) performance of the system under historic climate conditions and several future climate and sea-level rise scenarios for several CERP implementation scenarios. These CERP implementation scenarios could include

• Future without any CERP projects,
• Future with CERP projects as completed today,
• Future with all authorized CERP projects,
• Future with authorized CERP projects and CERP projects in planning, and
• Future with authorized and planned CERP projects plus potential alternative Lake Okeechobee regulation schedules.

A comparison among these climate and implementation scenarios would show the incremental benefits provided by CERP implementation and the sensitivity of these outcomes to climate change. Using several scenarios that encompass uncertainty about future climate, sea-level rise, and implementation enables exploration of what the future could hold for the CERP and provides a context for future planning and implementation, based on the current state of knowledge.

Future climate and sea level–rise scenarios could be defined from modeled projections that assume different representative concentration pathways (RCPs). The RCPs are four scenarios for greenhouse gas concentration made on the basis of expectations for 21st-century population change, income growth, technological improvements, and climate policies. The CERP mid-course assessment should consider future climate and sea level under two or more of these scenarios. For example, these could include RCP4.5, a relatively optimistic scenario, where deployment of policies and technologies mitigate emissions and stabilize radiative forcing, and RCP8.5, a high-end emissions scenario where emissions steadily increase over time.

Future climate assuming these emissions scenarios can be forecast with outputs from General Circulation Models (GCMs). The coarse-resolution GCM outputs are typically downscaled to higher spatial resolution using empirical-statistical methods, or they are used as boundary conditions in regional climate models that, in turn, yield outputs at high spatial resolution (DiNapoli and Misra,

2012; Misra et al., 2012b; Salathe et al., 2007; Selman et al., 2013; Wood et al., 2004). Downscaled climate projections from different GCMs never completely agree, leading to a key source of uncertainty in GCM-based climate forecasts. This uncertainty raises questions about how climate projections should be used in coupled hydrologic and ecological simulations. One answer is to weight climate model projections based on how well they match historical observations of pertinent climate variables, such as rainfall and temperature using a reliability ensemble averaging approach (Giorgio and Mearns, 2002) or Bayesian weighting approach (Tebaldi et al., 2005). An alternative to this performance-based approach—the so-called envelope approach—involves selecting a subset of GCM-based projections that cover the range of possible rainfall and temperature futures represented collectively in a large pool of climate models (Cannon et al., 2015; Immerzeel et al., 2013; Warszawksi et al., 2013). Obeysekera (2013) compared downscaled-GCM output to 20th-century observations for South Florida and showed that no single GCM simulated rainfall and temperature accurately enough for water-resource planning purposes. This realization led Obeysekera et al. (2015) to employ a simplified variant of the envelope approach to prescribe two mid–21st-century rainfall scenarios as a uniform ± 10% change around the historical rainfall time series. These rainfall scenarios, together with specifications of a 1.5^o C temperature increase and 1.5 ft rise in sea level over historic levels, were used in the SFWMM to simulate the responses of Everglades water levels and flows to climate change without any restoration projects in place.

Approaches for using different climate scenarios that are conditional on the spread in climate-model projections are available, have been tested to a limited extent in South Florida, and should be adopted for the CERP mid-course assessment. The spread in climate forecasts for South Florida may decrease with continued research and improvements in the representation of modeled processes, but considerable uncertainty about future climate will likely persist. Because the spread (uncertainties) in climate forecasts will propagate into hydrologic predictions, results of a coupled climate-hydrologic analysis will yield a spectrum of potential hydrologic futures. This spectrum could shift or even broaden when interactions with alternative projections for sea-level rise are incorporated into the analyses. Nevertheless, the complicating effects of climate change and sea-level rise should not be ignored. Rather they should be characterized and brought to the fore using decision making under deep uncertainty (DMDU) planning processes such as robust decision making (RDM) (Groves and Lempert., 2007; Lempert et al., 2006). These approaches can be used to identify projects that do or do not meet management goals under a large number of climate change and sea level–rise scenarios. Such decision support tools can help inform the design of restoration infrastructure that will be durable through

the 21st century and sufficiently flexible to perform under conditions that may be very different from those today.

Evaluation of the hydrologic and ecological outcomes achieved by each climate and implementation scenario would demonstrate the effect of projects already constructed and outcomes that might be achieved under future conditions following completion of major increments of the CERP. It would also illuminate ecosystem goals that are unlikely to be met as implementation of the current plan proceeds, providing a foundation for potential adjustment of CERP planning and implementation to achieve desirable outcomes in the face of climate change and to enable targeting of future investments where they can make a difference to the system for decades to come.

Outside of the CERP, the SFWMD is developing impressive expertise in decision making under deep uncertainty² that provides excellent frameworks for planning robust projects that deliver desired benefits across a wide range of possible future conditions. Following the mid-course assessment, the CERP agencies could use this expertise to inform future decision making.

SCIENCE TO ADVANCE THE CERP

Scientific understanding is fundamental to all aspects of Everglades restoration. It was crucial to the original development of the CERP and key advances made in the early years, such as the development of conceptual ecological models, were innovative and groundbreaking. Scientific knowledge is still advancing on many fronts, and new tools and approaches are being applied to yield insight on system dynamics and to support planning. However, there is an ongoing need for research and tool development to understand system change and how restoration affects it. This section presents several areas of research and tool development that would be useful components of a forward-looking science program to better support the CERP. These should be considered examples of the types of important issues that should be addressed. The committee also describes a programmatic approach to better support forward-looking research and development that is essential to the long-term success of CERP.

Research Needs to Support the Future Success of the CERP

Science support for the CERP, with its large and long-term infrastructure investments, requires attention to future stressors, their potential impacts on the South Florida ecosystem, and the implications for restoration. This section high-

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² See www.deepuncertainty.org.

lights examples of important research and tool development needs to support the future success of the CERP.

Improved Modeling of Coastal Boundaries in Regional Models

Given the vulnerability of South Florida to sea-level rise, there is a critical need to advance tools and research to better characterize and quantify its effects. The current regional hydrologic model used by the SFWMD (RSM) has been a valuable tool to estimate historical discharges through the Everglades and to project the hydrologic response of planned or potential water management and restoration strategies. RSM has also been useful in making preliminary assessments of potential seasonal and spatial changes in water stage and flows under different climate change scenarios (Obeysekera et al., 2015). One drawback of this tool is the lack of a coupled connection with the coastal system, specifically the ability to simulate salinity transport and variable density flow. Improving the capabilities of hydrologic modeling tools to capture the coupled interaction with changing coastal boundary conditions, including salinity transport, would support assessment of the impacts of sea-level rise and storm surges on the Everglades ecosystem for current as well as future conditions. Improving the model to address changing coastal boundary conditions would also improve the capacity to evaluate the benefits provided to near coastal areas by restoration alternatives. Such enhanced modeling capabilities can be used to examine Everglades restoration options to improve freshwater flows while depicting the interface with the marine environment, enhancing the reliability of future planning and project evaluation. Additional data along the coastal boundary would also be needed to calibrate the modeling tools used to simulate the impacts of the changing coastal boundary conditions.

Understanding Peat Collapse

An important uncertainty involves the response of coastal vegetation and peat to sea-level rise. Field research is under way on wetland response to seawater inundation through the Florida Everglades Long-term Ecological Research (LTER) program, which should provide a better understanding of the response of freshwater wetlands and peat soils to inputs of marine water. These experiments could supply important quantitative and process-based information on the phenomenon of peat collapse. The committee encourages continued landscape-scale research on the dynamics of coastal wetland ecosystems with seawater inundation. For example, can the landward migration of mangroves keep pace with sea-level rise? What is the mechanism(s) and timescale of peat collapse,

and how and at what rate do wetland ecosystems recover from this disturbance? Will the disturbance of seawater inundation alter the dynamics of phosphorus in these wetland ecosystems? This information will be critical to understanding the potential for freshwater flows to mitigate peat collapse.

Emerging remote sensing methods should prove useful in monitoring the landscape-scale dynamics of wetland response to saltwater inundation. An example of recent research along these lines is NASA Goddard’s Lidar, Hyper-spectral, and Thermal (G-LiHT) airborne imager (D. Lagomasino, University of Maryland, personal communication, 2018), which has been used to map the composition, structure, and function of terrestrial ecosystems, such as the mangrove forests along the coastal Everglades (Figure 6-6). G-LiHT data products and higher-level change maps are available through the G-LiHT Data Center.³ Data from tools such as this will be essential to tracking lateral shifts in habitats with sea-level rise and freshwater flow restoration.

An important output of additional research and monitoring of vegetation and soil response to sea-level rise would be the coupling of a wetland landscape model with a revised hydrologic model that integrates the dynamics of sea-level rise in hydrologic simulations. A landscape submodel capable of depicting the accumulation and loss of peat and changes in land surface elevation in response to changes in freshwater flows as well as seawater inundation would be a valuable tool for CERP agencies.

Risk Assessment for Invasive Species

The identification and management of invasive species in South Florida will continue to be challenging. Recent advances in EDRR (early detection and rapid response) (e.g., Crall et al., 2012; Thomas et al., 2017) demonstrate that this is an active area of research, and CERP agencies and their partners should remain at the forefront of this work. For example, one increasingly used method to evaluate the likelihood that a nonnative fish species will become established is the Fish Invasiveness Screening Kit (FISK) (Hill et al., 2017; Lawson et al., 2015). This kit, like other assessment tools, is a systematic arrangement and evaluation of information about species that considers aspects of their biology, likelihood of spreading in the ecosystem, and other factors to assess the risk that they pose to a particular ecosystem. Retrospectively applying the tool to 95 nonnative species that had been introduced into U.S. public waters, Lawson et al. (2015) found that it correctly classified 76 percent of invasive species and 88 percent of noninvasive species. They concluded that managers could use the tool to identify nonnative species likely to become invasive. Tools like this

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³ See https://gliht.gsfc.nasa.gov.

one could also guide research on established exotic species by evaluating the potential value of different kinds of information in a risk management context.

This approach is starting to be applied in the Everglades. For example, a screening tool has been developed to assess the need to initiate a rapid response, as well as the resources and knowledge available to support that response (see Chapter 3).

Delivering Decision-Relevant Scientific Advances

An array of providers supports the technical effort underlying CERP planning and implementation (e.g., SFWMD, National Park Service, U.S. Geological Survey, National Science Foundation, Sea Grant, other agencies and nongovernmental organizations). Work focused on the Everglades is largely conducted by scientists and engineers in government agencies and universities based in South Florida, although work conducted outside the system, such as on climate change prediction, is tapped when applicable.

The RECOVER program is often seen as the centerpiece of the Everglades science endeavor. In the early years, as agencies started to implement the CERP, it served as a focal point of innovation with leaders in science who could break new ground and link scientific understanding to emerging management needs. The Programmatic Regulations task RECOVER with adaptive assessment and monitoring. The group works to “organize and apply scientific and technical information in ways that are most effective in supporting the objectives of CERP.”⁴ Prior to project implementation, this work provided flexibility for the development of tools and approaches such as conceptual models. Now that project implementation is in full swing, the emphasis has shifted toward supporting project planning and evaluation of benefits. RECOVER has produced an impressive array of reports to support restoration, and the RECOVER Five-Year Plan (RECOVER, 2016), to some extent, recognizes the need to reframe some of the work of the early 2000s to address the current and future needs of the program. Managing the massive endeavor of monitoring the restoration of the Everglades, supporting the simultaneous planning of multiple projects, and delivering required reports inevitably means that project management has become as important a function for RECOVER leaders as scientific vision.

Although ongoing monitoring, evaluation, synthesis, and reporting are essential tasks for tracking the progress of CERP implementation, there is a need to focus research and development activities on the implementation issues to come. The accelerated 3-year project planning process has moved projects forward quickly, but it provides minimal time to develop new tools and approaches,

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⁴ See http://www.saj.usace.army.mil/Missions/Environmental/Ecosystem-Restoration/RECOVER/.

digest the insights provided by new research, or ensure that Everglades science stays on the cutting edge. For science to successfully underpin Everglades restoration for decades to come, scientists working on Everglades restoration must be able to develop concepts and tools that future projects, as well as programmatic assessment, will need. The South Florida Ecosystem Restoration Task Force chartered the South Florida Ecosystem Restoration Science Coordination Group in 2003 to develop a report that “tracks and coordinates programmatic level science and other research, identifies programmatic level priority science needs and gaps, and facilitates management decisions” and to provide scientific support to the Task Force. The most recent Plan for Coordinating Science was updated in 2010 (SFERTF, 2010). It not only embraces the need for monitoring, evaluation, and assessment, but also explicitly acknowledges research and modeling as key elements of restoration science. Recent meetings of the Science Coordination Group have been focused on specific issues such as the revision of the conceptual ecological models and a coordinated science response to Hurricane Irma, which are worthwhile but insufficient to frame long-term research needs.

Currently, given all of the ongoing activities that comprise the Everglades science enterprise, there is no obvious method to formulate, let alone realize, this vision for science. The complexity and scale of the system make it challenging to incorporate emerging science into the restoration program and to ensure the availability of cutting-edge and usable science for implementing agencies and resource managers. This issue could be addressed through establishment of a specific science program to support the future implementation of the CERP. Meeting this challenge requires designation of the responsibility for developing and making available the body of knowledge necessary to support restoration activities. This program would not replace the work of individuals in RECOVER and the agencies who currently conduct the investigations, analyses, and model development that support effective restoration planning and implementation.

The scientific community within the Everglades, including university researchers and nongovernmental and private-sector experts, is already informally connected through the highly successful biennial Greater Everglades Ecosystem Restoration conference. This event provides an opportunity for “bottom-up” identification of emerging scientific issues and has proven to be such a successful vehicle for supporting collaboration, communication, and dissemination of scientific developments that it has been adopted in the California Bay-Delta⁵ and in coastal Louisiana.⁶ An Everglades “science program” could convene additional exchanges to pursue promising ideas that fall outside the purview of RECOVER or specific agencies.

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⁵ See http://scienceconf2018.deltacouncil.ca.gov/.

⁶ See http://www.stateofthecoast.org/.

Although the Science Coordination Group facilitates science coordination related to ongoing activities, a designated science program could be a central point for setting a CERP-relevant science agenda that looks beyond the needs of the moment. The focus should be on specific research investigations to fill important gaps or drive innovative approaches to support restoration and could be pursued through a competitive process and leveraging of existing agency scientific investments. Program funds could be used, for example, to enhance direct collaboration between university and agency scientists or to pilot promising new concepts or approaches. The vision for the effort should not be difficult to develop. Everglades restoration agencies have a number of broadly knowledgeable, forward-thinking scientists who provide what CERP-level leadership they can, given their current positions and responsibilities. However, none of these is designated or empowered to take the reins of leading Everglades science forward for the next few decades.

Maintaining a focus on the importance of science for the future Everglades could be accomplished by establishing a new independent position of Lead Scientist. This individual would be responsible for high-level communication, delivery of technical products that respond to changing needs, and promotion of cutting-edge science in Everglades restoration—thereby freeing up time for individuals working in RECOVER or the agencies to deliver information to support day-to-day restoration and reporting activities. Again, there are several very capable, even visionary, senior scientists who provide leadership within their agencies, assume multiple roles within the CERP, and provide invaluable insight for Everglades restoration as a whole. However, there is no central leader to support Everglades restoration fully focused on a vision for science, its continued development, and application across agencies.

The Delta Stewardship Council in California provides a model for the Lead Scientist role. There, the Lead Scientist is appointed for a 2- to 3-year term, is often an individual on leave from a university position, and is responsible for leading, overseeing, and guiding the Council’s Science Program. Lead Scientists for the Delta Stewardship Council are credentialed Ph.D.’s who have themselves made substantial contributions, and are skilled in communicating to policy makers and respected by their peers. Limiting the term of the position would not only prevent burnout in such a central, high-visibility role, but also allow for fresh insights to guide the Everglades scientific community.

Establishing a science program and designating a single leader for science, who can step aside from their university or agency setting and focus on the available and needed science, could empower and invigorate the broader scientific community. The Lead Scientist for the Delta Stewardship Council serves as a spokesperson for the broad science community, which is especially important

when unpopular or politically charged scientific issues need to be communicated. Because of this role and administrative structure, the Delta Stewardship Council’s Science Program is viewed by all stakeholders as the “honest brokers” of science. Such a program for the Everglades could also embrace the following activities:

• Guiding the development and refinement of effective integrative modeling tools,
• Charting the transition to new technologies and tools as they become available and tested for readiness,
• Prioritizing the array of issues and uncertainties that could be researched to support restoration,
• Identifying needs for advances in synthesis, modeling, and analytics to improve the capacities and responsiveness of the adaptive management program, and
• Providing a single voice for communication of science at the highest level. For example, the Delta Stewardship Council Lead Scientist serves on the Delta Plan Interagency Implementation Committee and regularly testifies to legislative and policy bodies.

Such an approach would return Everglades restoration to the forefront of science-informed restoration (see NASEM, 2016). A recent workshop summary (USGS and Delta Stewardship Council, 2018) identified clear and effective science leadership and relationship building as critical to the success of any restoration science enterprise. For such a position to be successful in the Everglades will require backing and cooperation across agencies, and in turn the Lead Scientist must appreciate the differing roles and responsibilities of the agencies involved.

The committee recognizes the barriers to funding such a science program, given the CERP’s project-specific funding approach. However, relatively modest funds from the myriad of partners with spending flexibility and a direct interest in the science could be pooled to support a Lead Scientist and modest staff. Funding for research and development already exists but it not well coordinated, and pooling dollars could lead to efficiencies and lower the need for future funding requests.

CONCLUSIONS AND RECOMMENDATIONS

The Everglades of 2050 and beyond will differ from what was originally envisioned when the CERP was developed. The original CERP plan was formulated based on a pre-drainage vision of the historical Everglades and the assumption that specific rainfall and temperature time series observed in the past captured

the full range of variability expected throughout the 21st century. There is now ample evidence that the South Florida climate is changing. There is general consensus that temperatures will increase over time, although considerable uncertainty about future rainfall patterns remains. There is also compelling recent evidence that sea-level rise is accelerating. These changes will have profound impacts on the South Florida ecosystem and the related challenges of providing flood protection and meeting future water and recreational demands.

CERP agencies should conduct a mid-course assessment that rigorously considers the future of the South Florida ecosystem. New information about climate variability, climate change, and sea-level rise in South Florida continues to emerge, and many of these changes will impact the capacity for the CERP to meet its goals. Although the SFWMD has begun to conduct these types of analyses for planning and management projects outside of the restoration, CERP agencies do not adequately account for these changes when planning projects, and they have not systematically analyzed these threats in the context of the CERP. Restoration is likely to create important benefits that increase the resilience of the ecosystem in the face of climate change, but these benefits have not been adequately studied or quantified. A systemwide, program-level analysis should assess the resilience and robustness of the CERP to the changing conditions that will drive the Everglades of the future. A mid-course assessment should include systemwide modeling of interactions among both authorized and planned projects under scenarios of future possible climate and sea level–rise conditions. This assessment is essential to communicate the benefits of the CERP to stakeholders, guide project sequencing and investment decisions, and manage the restoration under changing conditions. Now that several major project planning efforts are nearing completion and the vision for CERP storage is largely developed, which will require decades to construct at current funding levels, the time is right for a mid-course assessment.

A science program focused on understanding impacts of current and future stressors on the South Florida ecosystem is needed to ensure that CERP agencies have the latest scientific information and tools to successfully plan and implement the restoration program. This report has highlighted the ongoing research advances and science that are needed to address issues of vital importance for the long-term success of restoration investments, such as understanding peat collapse, saltwater intrusion, and the management of invasive species. Ensuring that investigative research and advances in tools and understanding are useful in a policy context requires a programmatic approach directly linked to the CERP effort, which may be best championed by an independent Everglades Lead Scientist empowered to coordinate and promote needed scientific advances.