WCA3 Decomp

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WCA-3 Decomp Sheetflow EnhancementDesign
Coordination Team Meeting24 June 2008
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Desired Briefing Outcome

• After review of issues provide direction to team
• Go forward to QRB or not

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Recommendation for Application of IAR Principles
to Decomp

• Modify DECOMP PIR 1 Scope
• QQ Phase 1
• Raise and bridge (using 10 100-ft box culvert
  bridges) the eastern portion of Tamiami Trail and
  also completely backfill the Miami Canal within
  WCA 3
• SS
• North New River Improvements to improve discharge
  capability, if necessary to compensate for
  capacity lost via removal of Miami Canal
• NOT AA
• Additional S-345 structures in L67 A and C

PIR 1 is only looking at backfill S-8 to S-151
because of seepage and water supply
concerns. Items in red are proposed for PIR 1.
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Potential Issues for DecompTamiami Trail Feature
in PIR 1 (Raised May 20, 2008 DCT meeting)

• MWD legal challenge
• MWD/DECOMP boundary line
• WQ quality at S-333 S-12 w/ expanded PIR1
• S-333 stability w/ increase flows down L-67A
• What are Real Estate issues w/ expanded PIR1
• ENP Wilderness permits
• DPM- what questions will be answered
• Schedule and Cost Risk Analysis

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MWD Legal Challenge

• Lawsuit filed June 18, 2008
• Lawsuit focused on NEPA and FACA violations
• Per SAJ Office of Counsel Lawsuit should not
  affect Decomp planning efforts in any way
• Potential impact None anticipated at this time

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MWD/DECOMP Boundary Line

• Agreement was reached and documented in 90-day
  report to Congress on what constitutes finished
  MWD
• Recent SFWMD Governing Board member statements
  indicate this may no longer be the case
• State position may be that MWD is not finished
  until 4000cfs is passed under Tamiami Trail
• Potential Impact Time High Risk

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S-333 S-12 WQ concerns

• Differences in Total Phosphorus of deliveries to
  SRS via S-12 S-333 structures due to influence
  of canal flow (L-67A and L-29) versus marsh
  sheet-flow.
• Issue may need to be addressed if water is
  provided from S-333 for a bridge east of S-333
• PDT assumption to date CSOP and/or MWD
  Conveyance and Seepage features, Long-Term Plan
  would be in place before PIR 1 features, allowing
  more marsh flow through S333
• Analysis necessary, but there may not be a
  problem.
• Potential Impact Time Medium Risk

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S-333 Stability Concerns

• Potential for adverse impact to rip-rap
  downstream of S333 at flows exceeding 1350 cfs
• Decomp PDT not suggesting flows greater than 1350
  cfs for Decomp PIR 1.
• CSOP not anticipated to use all of S333 capacity,
  rather S-355 A and B as the preferred flowpath.
• Decomp team still researching timing.
• Potential Impact None anticipated. Low Risk.

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Real Estate Issues

• Several types of issues
• Lands requiring purchase by ENP
• Miccosukee Tribe Camps in which structures must
  be raised
• FDOT relocation agreements
• Utility relocation agreements
• Potential Impacts Time (for purchase of lands
  and negotiation of agreements), and Cost
  (particularly to Park) Medium Risk

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ENP Wilderness Permits

• ENP cannot guarantee issuance of wilderness
  permit prior to application.
• ENP committed to working with us to get through
  permit application process.
• Wilderness Committee Rep informed us NESRS does
  not have as strict permitting requirements as
  other parts of the park permits in that area can
  be expedited, if there is no need to build
  structures.
• Team has application process for monitoring
  permit
• Potential Impact Time Medium Risk

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What is the Decomp Physical Model?

• A pilot study to test engineering solutions for
  ecological restoration.
• An on-site, large-scale controlled manipulation
  of the environment to evaluate ecosystem response
  to sheetflow.
• A landscape manipulation designed to provide
  critical information of the hydrologic targets
  for restoration.
• Provides ecological lift to a drained system
  An Adaptive Management approach.

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Questions to be answered by a physical model.
Uncertainty 1 Hydrology Do canals need to be
completely backfilled in order to achieve
hydrologic restoration? Uncertainty 2
Sediment What is the role of floc and sediment
movement for restoring and sustaining a stable
ridge and slough landscape, and how do canals,
levees, and levee modifications affect this
movement?. Uncertainty 3 Restoration What is
the ecological function of sheetflow and what are
the hydrologic needs (i.e., flow fields, depths,
duration) of the ridge and slough landscape?
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The objectives and issues that make a DECOMP
Physical Model (DPM) important.
Objective 1 Evaluate the impacts of sheetflow,
weirs, and canal backfilling (partial vs.
complete) on the processes associated with the
restoration and sustainability of the
ridge-slough-tree island pattern in the
Everglades. Issue Recreational fishing
interests do not want canals to be backfilled.
However, there is scientific evidence to suggest
that canals that are not backfilled will
short-circuit marsh hydrology, interfere with
sediment transport, cause water quality problems,
and create habitat for exotic fish.
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Objective 1 Remove the impacts of impoundments,
levees and canals.
Pre-drainage ridge slough landscape
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The objectives and issues that make a DECOMP
Physical Model (DPM) important.
Objective 2 Assess the physical and
biogeochemical parameters associated with
sheetflow as a way to develop, improve and
parameterize the tools needed to evaluate Decomp
alternatives. Issue Hydrologic performance
measures for the restoration of tree islands,
ridges, and sloughs do not yet include velocity
vectors. The NSM is not calibrated for flow
fields and no one knows if current peak flow
rates of 1 cm/sec can support the biophysics of
restored microtopography in the Everglades.
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Objective 2 How much sheetflow is enough?

Present-day Flows
Historic Flows
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What objectives and issues can be addressed with
Adaptive Management?
Objective 3 Evaluate the role of floc and
sediment movement for restoring and sustaining a
stable ridge and slough landscape. Issue
Wading birds need slough habitats during the dry
season for intensive foraging to support nesting
and fledging of young birds. Wading bird
populations can not be restored if the slough
habitats of the Everglades continue to be
encroached by sediments, cattails and sawgrass.
However, there is no scientific understanding of
the biology of floc or its distribution
movement across the Everglades.
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Objective 3 Restore ridge and slough
microtopography.
Healthy Microtopography
Impacted Microtopography
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DPM Prius Concept- Design linked to MWD CSF
features to move water continuously and as pulsed
releases along historic flow paths from WCA-3A
through large, controlled openings in the L-67A
levee, to canal and levee modifications on the
L-67C. DPM Prius Design Factors- 1. A focus on
hydrodynamics and sediment movement occurs in a
BACI flow-path 2. Long-term statistical
variation associated with ecological parameters
is handled by a Repeated Measure design. 3.
Research schedules are linked to the construction
of MWD CSF features.
Prius Model v3.5
3000 ft gap complete backfill
BACI Flow-way with one 12,000 ft L-67C levee gap
3000 ft gap partial backfill
3000 ft gap no canal fill
Repeated Measure Flow-way
CSOP L-67A weir-culvert cluster location
L-67A Levee
Canal plug with boat channel
L-67C Levee
Gaps L-67C levee openings
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DPM Lite Concept- Design not linked to MWD CSF
or DECOMP features as a result, move water only
as pulsed releases along historic flow paths from
WCA-3A through controlled openings in the L-67A
levee, to canal and levee modifications on the
L-67C. DPM Lite Design Factors- 1. All
hydrodynamics, sediment movement, and ecological
studies occur in a BACI flow-way 2. Long-term
implications are extrapolated from short-term
impacts. 3. DPM constructs temporary L-67A
features independent of MWD CSF and DECOMP.
DPM Lite v1
3000 ft gap complete backfill
3000 ft gap partial backfill
BACI Flow-way with one 12,000 ft L-67C levee gap
3000 ft gap no canal fill
L-67A Levee
5-6 temporary gated culverts
L-67C Levee
Gaps L-67C levee openings
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Differences between Prius v3.5 and DPM Lite v1.
These two models address the same suite of
questions. The difference is the degree of
statistical rigor, the manipulation of water used
to evaluate ecosystem responses and the
connectivity between WCA3B and ENP.

• DPM Lite evaluates short-term hydrologic pulses,
  while Prius evaluates longer-term
  geomorphological and ecological responses.
• DPM Lite evaluates floc movement within
  short-lived flow fields, while Prius model
  examines longer-term floc transport.
• DPM Lite flow fields are limited in their ability
  to elicit longer-term ecological consequences.

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Decomp Physical Model Cost

• Team assuming either option will be designed,
  constructed and monitored within the 10.3
  million budget already approved for DPM

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Physical Model Current Draft Schedule
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Risk Analysis for Modified PIR 1 Scope

• Schedule Risk High
• Basis
• Feature(s) not clearly defined
• Tasks for modified scope not yet clearly defined
• Issues may not all be clearly identified (real
  estate, NEPA impacts)
• Projects already competing for Corps labor
  resources and hiring/development of new labor
  resources will be multi-year effort
• Risk could be lowered by dedicating team (as MWD
  or HHD)
• Budget Risk High
• Basis
• Budget would increase, compared to current scope
• Feature(s) not clearly defined
• Tasks for modified scope not yet clearly defined
• Issues may not all be clearly identified (real
  estate, NEPA impacts)
• Risk slightly lower than schedule risk because
  some schedule slips (issue resolution) do not
  require expenditure of labor resources
• Ecological Risk Reduced
• Basis
• Modified scope would jump start faster
  implementation of features that will help reverse
  the decline of the Southern Everglades, ENP and
  Florida Bay

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Risk Analysis for Current PIR 1 Scope

• Schedule Risk Low-Med
• Basis
• Fewer interagency issues to resolve
• Support by Corps and SFWMD leadership
• Corps labor resources can focus on Miami Canal
  and Physical Model tasks
• Using new model may require unforeseen resources
• Budget Risk Low-Med
• Basis
• There is less uncertainty associated with
  planning tasks, issues and costs for current
  scope
• Ecological Risk Increased
• Basis
• Current scope would lead to slower implementation
  of features that will help reverse the decline of
  the Southern Everglades, ENP and Florida Bay

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Schedule Implications for PIR 1

• PIR 1 Estimated Schedule Slip
• Low 6 months
• If necessary activities completed according to
  PIR template durations
• If interagency and policy issues resolved quickly
• Middle 12 months
• If water quality, policy or interagency issues
  cannot be resolved
• High 18-24 months
• If water quality, policy or interagency issues
  become intractable

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Budget Implications for PIR 1
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Questions?