Progress Toward Restoring the Everglades The Sixth Biennial Review - 2016 (2016) / Chapter Skim
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4 Implications of Knowledge Gained Since 1999 for the CERP
4 Implications of Knowledge Gained Since 1999 for the CERP
Pages 133-178
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From page 133... ...
The Central Everglades Planning Project (USACE and SFWMD, 2013a) was developed and approved as a comprehensive approach to combine components of several CERP projects and provide incremental benefits associated with increased flows through the central Everglades and a modest reduction in damaging regulatory releases to the northern estuaries (NRC, 2014)
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From page 134... ...
Additionally, a modified regulation schedule has substantially reduced natural storage in Lake Okeechobee, which could impact the capacity to reach CERP goals with the original plan. New understanding of climate change and sea level rise also presents the potential for significant changes in the future conditions that were not anticipated in the Yellow Book (NRC, 2014)
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From page 135... ...
An example that illustrates the challenges of setting restoration goals in the context of changing baselines is management of the Cape Sable seaside s parrow, an endangered subspecies whose entire global distribution is limited to Everglades National Park, and the marl prairie habitat in which it resides. There are three marl prairies in Everglades National Park: Ochopee marl prairie, west of Shark River Slough; Rockland marl prairie, east of Shark River Slough; and Perrine marl prairie, farther south in the vicinity of Taylor Slough.
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From page 136... ...
4-1 as "Shark Slough." The central Everglades currently receives about 67 percent of estimated predrainage raster, not editable River Slough current receives about flows, while full CERP implementation approaches 86 percent. Shark 40 percent of the estimated predrainage flows, while full CERP implementation approaches 65 percent.
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From page 137... ...
The flows themselves are tabulated in Table 4-1-1. Note that the annual flow volumes indicated on Figure 4-1-1 cannot be directly compared to those in continued FIGURE 4-1-1 Transects used for comparison of annual overland flow between the NSM and NSRSM.
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From page 138... ...
. This supposition was based on flows being reduced in western Shark River Slough, where current conditions in the adjacent Ochopee marl prairie occupied by sparrow subpopulation A are too wet and increased flows in northeastern Shark River Slough, where current conditions in the adjacent Rockland marl prairie occupied by subpopulations C, E, and F are too dry (see Figure 3-6)
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From page 139... ...
This illustrates the complexity of establishing restoration goals. An updated program review of restoration goals is essential to future planning and would include a realistic assessment of what can be achieved, includ FIGURE 4-2 Projections of habitat suitability for Cape Sable seaside sparrows from NSM (left)
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From page 140... ...
Current restoration plans (Fig ure 4-1) focus on increasing dry season flows rather than peak flows, although the CERP and the Central Everglades Planning Project more closely approach pre-drainage flows into WCA-3A compared to flows into Everglades National Park (Figure 4-1)
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From page 141... ...
over the period of record. Overlain on this record starting in 1992 are three USACE sea-level rise projections: the historical sea level trend; an intermediate trend projection; and a high rate projection.
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From page 142... ...
With intermediate USACE projections of sea level rise (24 inches or 0.9 m by 2100) , some restoration project benefits will be substantially reduced (e.g., Central Everglades benefits, by the loss of wetlands within the project footprint; USACE and SFWMD, 2014a)
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From page 143... ...
Greater flow through Shark River and Taylor Sloughs will likely mitigate the impacts of sea level rise to some degree, reduce hypersaline conditions in Florida Bay, and promote mangrove growth leading to reduced impacts from cyclonic storms (Orem et al., 2015)
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From page 144... ...
. Implications of Climate Change and Sea Level Rise for CERP Disturbance in ecosystem functioning associated with sea level rise and climate change may necessitate that restoration goals be revisited (NRC, 2014)
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From page 145... ...
Although NRC (2014) stated that "climate change provides a strong incentive for accelerating restoration," the committee did not suggest that changing climate and sea level rise provides a blanket endorsement of all CERP projects.
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From page 146... ...
For example, how does sea level rise affect restoration goals for Everglades National Park? Should climate change and sea-level rise mitigation and adaptation be consid ered equally among other CERP goals?
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From page 147... ...
The results consider only undiverted flow from C-43 watershed and exclude regulatory releases from Lake Okeechobee. sfwmd.gov/portal/page/portal/xweb%20about%20us/reviving%20the%20 river%20of%20grass%20-%20resops%20model • Management of Lake Okeechobee as an ecological resource by modifying the lake's regulation schedule to reduce the extreme high and low levels that damage the lake and its littoral zone, while allowing the lake to continue to serve as an important source for water supply Specific locations and engineering details for most storage projects were not determined in the Yellow Book (USACE and SFWMD, 1999)
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From page 148... ...
Potential storage in projects not yet planned, or planning not 292,120 finalized: In-ground reservoirs North Lake Belt 90,000 Feasibility unproven Central Lake Belt 187,200 Feasibility unproven L-8 Basinb 48,000 FEB operated for water quality, not storage Total in-ground reservoir storage 325,200 Projects planned to date 48,000 0 Potential storage in projects not yet planned, or planning not 277,200 finalized: a Updated capacity based on difference between an assumed low level of 9 feet and the highest stage in the upper band (17.25 feet for Lake Okeechobee Regulation Schedule (LORS) 2008 and 18.5 feet for Water Supply and Environment [WSE]
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From page 149... ...
. Note that although the storage capacity decreased significantly between the original CERP framework and the final IRL-S PIR, modeling analyses showed that the CERP objectives for the IRL-S project could be reached with substantially less storage.
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From page 150... ...
The WCAs are not currently operated as reservoirs, although flows in and out of the WCAs are managed according to regulation schedules that have been established to address multiple objectives, including limiting seepage (and associated flooding) to the east, enhancing conditions for endangered species, and providing rain-driven flows to Everglades National Park and water supply to the Lower East Coast.
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From page 151... ...
Despite the importance of these projects to overall system benefits, they will not be discussed in this chapter because the incremental storage and volumetric flow benefits associated from these individual projects are difficult to determine with existing information. The major CERP storage features, including surface and in-ground storage and aquifer storage and recovery, and their updated status are discussed in the following sections.
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From page 152... ...
In sum, out of more than 1,500,000 AF of storage capacity proposed in above-ground and inground storage features in the Yellow Book, projects planned to date represent only 386,000 AF of storage (including the 56,000-AF A-2 FEB)
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From page 153... ...
As of 2015, the SFWMD has established over 89,000 AF of dispersed water storage capacity in the Kissimmee, Caloosahatchee, and St. Lucie watersheds through a program that pays ranchers for providing storage on private lands (SFWMD, 2015b)
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From page 154... ...
The project delivery team determined that a reservoir at this site was not feasible because surficial materials at the site are highly transmissive.b The project was instead merged into the Everglades National Park Seepage Management Project. The 2015 Report to Congress indicates that the objectives of this feature would be provided by the Central Everglades Planning Project.
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From page 155... ...
This report is based on modeling that used the higher Water Supply and Environment (WSE) regulation schedule (see Lake Okeechobee Operations, later in this chapter)
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From page 156... ...
Indian River Lagoon and the Upper East Coast The CERP Yellow Book included plans for extensive storage in the Upper East Coast to attenuate high flows by capturing local runoff, providing water supply including low-flow augmentation for the Indian River Lagoon and St. Lucie River Estuary, and improving estuarine water quality.
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From page 157... ...
Overall, the storage provided in the EAA on state and federal lands in the CERP is substantially lower than that envisioned in the Yellow Book. The 240,000-AF capacity in the EAA Reservoir devoted to providing new water supply for the environment has effectively been replaced by a 56,000-AF FEB that 3 See http://my.sfwmd.gov/portal/page/portal/xweb%20protecting%20and%20restoring/ estoration r %20progress.
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From page 158... ...
states that the Central Everglades project features would replace the EAA Reservoir, and no future CERP costs are projected associated with the EAA Reservoir project. There has been no analysis to evaluate the implications of various levels of additional storage in the EAA (including no additional storage beyond CEPP)
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From page 159... ...
These sites were part of an "eastern flow-way" that captured urban stormwater runoff in Broward and Miami-Dade Counties and routed this water, in addition to water from WCAs 2 and 3, into Northeast Shark River Slough and Biscayne Bay. The Lake Belt reservoirs provided storage to alter the timing of flows and provide water when it is most needed during the dry season.
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From page 160... ...
No CERP analyses have been conducted to determine the impact to CERP outcomes if the Lake Belt features are never constructed or the feasibility of replacing these features with storage elsewhere in the system. Aquifer Storage and Recovery In the original Yellow Book plan, ASR represented a large fraction of the total CERP storage and provided important long-term storage benefits.
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From page 161... ...
Background and History of Lake Regulation Schedules In 1951, the USACE implemented a formal schedule with distinct regulatory bands, which define seasonally varying water levels that, when exceeded, triggered water discharges from the lake (USACE, 1978)
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From page 162... ...
An evaluation of the 1978 regulation schedule (SFWMD, 1988) concluded that the schedule's high water levels were not necessary to meet water use demands and resulted in damag large volume releases of freshwater to the Saint ing Lucie and Caloosahatchee estuaries.
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From page 163... ...
. The USACE also adopted a new lower Lake Okeechobee regulation schedule (LORS; USACE, 2007d)
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From page 164... ...
If the upper band of lake regulation schedule is not increased once the Herbert Hoover Dike repairs are completed or if the storage is not replaced by other projects, this would result in substantially reduced water availability for environmental, agricultural, or urban uses and a lower reduction in harmful high-volume discharges to the estuaries than anticipated in the original CERP. On the other hand, the environmental impact statement for the current schedule indicated that it would provide substantive benefits for the lake's littoral zone, and in fact, the acreage of submerged and emergent plants has been at record
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From page 165... ...
-- though it is unclear whether this is because of the regulation schedule or a period of below-average rainfall in some of the years. Options for Increased Future Water Storage in Lake Okeechobee At this time, the USACE has not determined what, if anything, will be done with the Lake Okeechobee regulation schedule once rehabilitation of the Herbert Hoover Dike (see Chapter 3)
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From page 166... ...
At the same time, WSE had a lower risk of long lasting high flow events to the northern estuaries, which can negatively affect estuarine biota. The EIS indicated little difference between the two schedules regarding WCA performance measures (tree island flooding and peat dry-out)
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From page 167... ...
Paudel, Everglades Foundation, personal communication, 2016) , to illuminate the difference in restoration benefits from the current lower regulation schedule, in case the water levels allowed within this schedule are not increased in the future schedule modifications.
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From page 168... ...
resulted in a slight increase in the occurrence of low and high water levels. However, when LORS 2008 is retained as the regulation schedule in CERP (Scenario BLORS)
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From page 169... ...
A: Base Condit ions B: C: BLORS: CLORS: (LORS) CERP Scaled-Back CERP CERP Scaled-Back CERP Mean annual flood control 150 28 49 45 57 (regulatory)
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From page 170... ...
A: Base Conditions B: C: BLORS: CLORS: (LORS) CERP Scaled-Back CERP CERP Scaled-Back CERP Mean annual flood control 390 78 131 182 208 (regulatory)
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From page 171... ...
. Water Levels and Flows in the Remnant Everglades Changing the lake regulation schedule has little effect on water levels or flows to various parts of the remnant Everglades.
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From page 172... ...
. The differences seem largely driven by the removal of the Lake Belt reservoirs in Scenario C
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From page 173... ...
Compared to Scenario B (CERP) , under Scenario C, the average annual reduction in flow is 111,000 AF, with 49,000 AF less during the wet season and 62,000 AF less flow in the dry season on average.
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From page 174... ...
Reductions in benefits due to scaling back the CERP were not as dramatic as in the northern estuaries, but were consistent. Implications for CERP Planning Collectively, the knowledge gained since the start of the CERP has profound implications for restoration outcomes.
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From page 175... ...
Revisions to the Lake Okeechobee Regulation Schedule The future lake schedule is critically important to future CERP planning decisions regarding storage north or south of the lake. The adoption of the LORS 2008 schedule, intended to reduce life safety risks in light of structural problems with the Herbert Hoover Dike (see Chapter 3)
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From page 176... ...
CONCLUSIONS AND RECOMMENDATIONS Knowledge gained regarding the pre-drainage system, climate change, and sea level rise suggests that a reexamination of the CERP restoration goals -- including both ecology and hydrology -- is in order, together with a r ealistic assessment of what can be achieved. It is now widely accepted that the Everglades ecosystem was much wetter historically than previously thought.
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From page 177... ...
Major reductions in storage capacity are associated with the replacement of the EAA and L-8 Reservoirs with FEBs, the largely reduced capacity of regional ASR, the uncertain feasibility of the Lake Belt reservoirs, and the implementation of a new Lake Okeechobee regulation schedule. The amount of storage capacity provided by planned and authorized CERP projects to date plus the Central Everglades Planning Project (386,000 AF)
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From page 178... ...
The process to revise the Lake Okeechobee regulation schedule should be initiated as soon as possible in parallel with the Herbert Hoover Dike modifica tions to inform near-term project planning involving water storage north and south of the lake. The large impacts on water storage with just modest changes in the lake regulation schedule suggest that Lake Okeechobee is a central factor in future considerations of water storage.
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