Progress Toward Restoring the Everglades The Eighth Biennial Review - 2020 (2021) / Chapter Skim
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4 Combined Operational Plan
4 Combined Operational Plan
Pages 111-154
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From page 111... ...
and its boundary with Everglades National Park and the 2012 Water Control Plan for the C-111 Basin and, therefore, has implications for much of the central Everglades. Past reports of this committee have highlighted the ongoing degradation of the natural system in the central Everglades and the lack of restoration progress in this area (NRC, 2008, 2012)
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From page 112... ...
112 Progress Toward Restoring the Everglades FIGURE 4-1 The non-CERP Modified Water Deliveries and C-111 South Dade, the Limestone Product Association seepage barrier (dark red in the figure) , and the CERP C-111 Spreader Canal Western Project all are expected to contribute to increased flows in Northeast Shark River Slough and Taylor Slough in Everglades National Park.
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From page 113... ...
The following sections describe some of the key issues influencing restoration efforts in Shark River Slough through Mod Waters, and Taylor Slough and eastern Everglades National Park through the C-111 South Dade Project, to provide context for understanding COP benefits. Shark Slough and Mod Waters Prior to the construction of the WCAs, approximately two-thirds of the flow into Shark Slough came through Northeast Shark River Slough based on the natural gradients in the system (Figure 4-2)
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From page 114... ...
That the CERP was authorized immediately following this crisis is not coincidental. The Everglades National Park Protection and Expansion Act of 1989 autho rized Mod Waters and directed the U.S.
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From page 115... ...
Following the demise of the Experimental Water Deliveries Program and while construction of Mod Waters continued, water management at the boundary of WCA-3A and Everglades National Park was governed by interim operational plans1 to protect the CSSS. These operations plans suffered from the same flood risk management constraints that compromised the Experimental Water Deliveries Program and thus fared little better in increasing flows to Northeast Shark River Slough (Figure 4-3)
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From page 116... ...
for Mod Waters finalized Northeast Shark River Slough and relieve high flows from (USACE, 1992) WCA-3A to Western Shark River Slough.
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From page 117... ...
the ERTP -- implemented in 2012. Like the operations plans that preceded it, the ERTP attempted to improve hydrologic conditions in the central Everglades within the constraints of existing infrastructure, specifically by shifting flow from Western to Northeast Shark Slough, increasing flows into Everglades National Park, and reducing ponding of water in southern WCA-3A.
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From page 118... ...
. This increased elevation, combined with the 1-mile bridge constructed through Mod Waters and the 2.6-mile western bridge constructed through Tamiami Trail Next Steps, enables increased flows into Northeast Shark River Slough and Everglades National Park.
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From page 119... ...
. The objectives of the C-111 South Dade Project are to reduce freshwater canal discharges to Manatee Bay and Barnes Sound and restore hydrologic conditions in Taylor Slough and the Eastern Panhandle of Everglades National Park, thereby increasing overland flows to northeastern Florida Bay, while continuing to honor flood risk management constraints for the agricultural lands east of the park (USACE and SFWMD, 2020c)
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From page 120... ...
In the 8.5 square-mile area the con straint required no increase in periodic flooding of lands within the levee over pre–Mod Waters baseline conditions, based on the Everglades National Park Pro tection and Expansion Act of 1989 (Public Law 101-229)
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From page 121... ...
• I ncrement 1 (2015-2017) relaxed existing constraints on gage G-3273 related to flow from WCA-3A into Northeast Shark River Slough, while maintaining the L-29 Canal at the stage of 7.5 feet National Geodetic Vertical Datum (NGVD)
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From page 122... ...
, which, respectively, emphasized flood mitigation for South Dade, providing the most flows into Northeast Shark River Slough, and balancing each. Results were reviewed and evaluated by subteams representing ecological, flood risk, water quality, and water supply issues.
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From page 123... ...
. Each of these alternatives satisfied constraints identified at the outset of the planning process, while differing with respect to rules for water deliveries to Everglades National Park, flood mitigation operations within the 8.5 squaremile area, provision of flows to Taylor Slough, operation of S-197, and protocols during high-water conditions within WCA-3A.
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From page 124... ...
While enhancing flow into Northeast Shark River Slough, Alternative Q+ reduces flows into Western Shark River Slough and incorporates the reasonable and prudent action of the 2016 ERTP biological
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From page 125... ...
only quantifies a portion of the benefits provided by this infrastructure. For example, model-simulated, average annual flows across a transect in Northeast Shark River Slough were three times greater under ECB19RR than during pre-ERTP (prior to 2012)
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From page 126... ...
. The graphs show the sizable increase in flow between pre-ERTP condi tions and the COP baseline, reflecting benefits attributable to the Mod Waters and C-111 South Dade infrastructure not captured in the COP Environmental Impact Statement analysis.
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From page 127... ...
from 58 to 77 percent. The increase in flows across the trail will be accompanied by longer hydroperiods within the Everglades National Park, particularly in Northeast Shark River Slough (Figure 4-7)
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From page 128... ...
Note that this difference plot does not capture sizable benefits already achieved through increment 1.2 using the Mod Waters and C-111 South Dade infrastructure.
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From page 129... ...
Benefits to Vegetative Communities Hydrologic changes induced by implementation of the COP will promote ecological responses. Increases in hydroperiod within Northeast Shark River Slough and Taylor Slough are expected to reduce soil-oxidation rates, thereby promoting accretion of peat.
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From page 130... ...
Estimates of this performance measure are similar for the no-action and Alternative Q+ scenarios for areas west of the Miami Canal in northern WCA-3A, although Alternative Q+ scores are slightly lower than the no-action alternative or Alternative O in the remaining portion of WCA-3A and WCA-3B. Within Everglades National Park, Alternative Q+ performed better for the index in Northeast Shark River Slough and southern 2 The slough-vegetation performance measure was based on optimal hydrologic conditions to promote white water lily and bladderwort, which historically dominated Everglades sloughs under predrainage conditions.
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From page 131... ...
indicate that the COP will result in improved foraging conditions for storks over large areas of northern and northeastern Everglades National Park (USACE, 2020b)
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From page 132... ...
In the mid-1990s, WCA-3A was their primary nesting area, but restrictions in flows to Western Shark River Slough to protect CSSS resulted in water ponding in southern WCA-3A, exacerbating ongoing degradation of kite foraging habi tat. As habitat conditions degraded, numbers of kites and kite nests declined and the distribution of nests shifted (NRC, 2012)
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From page 133... ...
To prevent the COP from suffering the same fate as Experimental Water Deliveries and ERTP, it will be necessary to avoid exceedances established for incidental take for the CSSS. The poor current condition of the CSSS population, combined with impacts of the redistribution of water under the COP at the local scale, makes this very challenging.
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From page 134... ...
It will be difficult to achieve progress toward the population goals and avoid violating this minimum population size requirement and thus triggering more consultation. Based on modeling results using climate data from 1965 to 2005, USACE (2020b)
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From page 135... ...
Although modeling data are not available to compare the COP to the ERTP or pre-ERTP conditions, one can estimate the effects of implementation of the Mod Waters and C-111 South Dade infrastructure by comparing the COP modeled output for 1992-2005 to the observed conditions for the same period based on data of FWS (2016a)
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From page 136... ...
suggest that restoring the historic distribution of flow between Western and Northeast Shark Slough, although beneficial to sparrows at a large scale, will not necessarily resolve 14 Observed Baseline AltQ 12 10 8 6 4 2 0 A B C D E F Subpopulation FIGURE 4-12 Number of years between 1992 and 2005 in which the criterion of a 4-year running average hydroperiod of 90-210 days over 40 percent of the habitat for each CSSS subpopulation was observed (blue bars) or was projected to occur under ECCB19RR baseline conditions (orange bars)
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From page 137... ...
. Increased flows to Northeast Shark Slough and Taylor Slough will produce a complex mix of improvements in some areas and adverse effects in others.
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From page 138... ...
as the committee. It reached the same conclusions about much of the benefit from Mod Waters and C-111 South Dade to sparrows being captured in the ECB19RR baseline and modest benefits for the problematic subpopulation A
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From page 139... ...
One can imagine demands to constrain flows to Northeast Shark River Slough and Taylor Slough to protect the sparrow, impacting broader ecological restoration goals for the region. Active mitigation for sparrows is the key to integrating Everglades restoration goals with CSSS recovery.
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From page 140... ...
The following comments address points where the process could more fully follow best practice and be a true exemplar for future CERP project development. Consideration of Model Uncertainty The best practice approach in modeling is to characterize the uncertainty of the models being used (Lehrter and Cebrian, 2010; Rinderknecht et al., 2012; Ruppert et al., 2012)
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From page 141... ...
Multiple performance metrics were considered, including both ecological performance and effects on flood risk, as well as considerations related to water quality and water supply. However, even though the objectives for COP were strictly ecological, it is not clear that the selected Alternative Q+ provides the most ecological benefit, particularly in comparison to Alternative O, and what role other factors, labeled planning considerations and concerns, played in project evaluation.
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From page 142... ...
COP ADAPTIVE MANAGEMENT The COP provides a tremendous opportunity for learning with respect to restoring the central Everglades, with valuable lessons for the CEPP. As water is redistributed in the central Everglades under the COP, projected changes in hydrology can be compared to observed changes, and projected responses of the ecology can be compared to observed responses.
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From page 143... ...
is quite comprehensive and is comprised of several parts, including monitoring plans and a component labeled COP Adaptive Management that focuses on COP operations. Even though the COP is a non-CERP effort, the adaptive management component follows the blueprint established for CERP adaptive management (USACE and SFWMD, 2011b)
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From page 144... ...
There are obvious systemwide implications of the hypotheses testing for most of the COP uncertainties, provided the cause of deviations from expectations can be determined. For example, flood mitigation for the 8.5 square-mile area and seepage issues on the eastern boundary of Everglades National Park have implications not only for COP benefits, but also for restoration of the central Everglades moving forward.
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From page 145... ...
• Tamiami Trail Flow Formula and drought: Based on consideration of the upstream water availability is there an opportunity to deliver water to Northeast Shark River Slough in a specific manner such that the delivery enhances freshwater flows to Florida Bay by delivering more water during the dry season without harming the ecological condition of WCA-3? • Florida Department of Transportation constraint on Tamiami Trail: Can L-29 Canal elevations be raised to 8.5 feet NGVD for more than 90 days per water year without adversely impacting the safety and stability of the Tamiami Trail roadway between S-333 and S-334?
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From page 146... ...
Water Quality • Water quality in Taylor Slough: Will there be downstream biogeochemical effects associated with modifying inflows and hydrologic conditions in ENP that result in detrimental effects on nutrient movement, availability, and ecological responses? • Water quality in Northeast Shark River Slough: Will there be downstream biogeochemical effects associated with modifying inflows and hydrologic conditions in ENP that result in detrimental effects on nutrient movement, availability, and ecological responses?
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From page 147... ...
The monitoring plans should be evaluated to determine whether additional monitoring that is better connected to COP adaptive management decisions and targets is needed to augment the current monitoring. For example, several monitoring programs are based on a stratified random sampling scheme (Evans et al., 2019; Philippi, 2007)
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From page 148... ...
Only 8 percent of the management options are in category A, and these address two uncertainties -- Northeast Shark Slough water quality and the TTFF. The remain ing management options may require additional NEPA permitting and review, which typically is a time-consuming hurdle.
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From page 149... ...
Wildlife coordination calls can provide recommendations to operations managers and periodic science calls, and periodic science calls can provide recommendations to operations managers. Although operations managers typically have the authority to make adjustments to operations within the flexibility existing within the Water Control Plan based on these inputs and their own deliberations, none of the management options contained in the COP Adaptive Management component falls within the decision-making authority of operations managers.
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From page 150... ...
Other Opportunities for Learning Overall, the COP Adaptive Management component focuses on project-level learning and adaptive management, but there are additional opportunities for systemwide applications of learning and programmatic adaptive management. Specifically, additional activities to compare modeling predictions to observed system behavior could be applied that would improve systemwide understanding and modeling tools, thereby benefiting both the COP and the CERP as a whole.
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From page 151... ...
These improvements, like the improvements in understanding of the system gained through comparing observations to predictions, have systemwide applications that will benefit CERP planning and programmatic adaptive management. CONCLUSIONS AND RECOMMENDATIONS The COP is expected to provide substantial hydrologic and ecological benefits to WCA-3A and Everglades National Park, although the full benefits from
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From page 152... ...
CERP projects and Tamiami Trail Next Steps are designed for a stage of 9.7 feet NGVD in the L-29 Canal. Without additional flood mitigation projects or seepage control efforts, flood risk management on the eastern edge of Everglades National Park could greatly limit the benefits of the CEPP.
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From page 153... ...
However, trade-offs among various objectives and other "planning considerations and concerns," such as flood risk management, were neither transparent nor well documented, leaving stakeholders unclear whether ecological objectives were compromised for other considerations. Lack of characterization of model uncertainty limits the potential application of adaptive management, because when observations fall outside of model projections, it is unclear whether this is due to model error or whether the system is not responding as expected.
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From page 154... ...
Furthermore, the evidence-based decision making required to achieve COP objectives will benefit from programmatic linkages to share decision-relevant information from other CERP projects.
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