 Decomp |
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What is DECOMP? DECOMP is the
“keystone” of Everglades Restoration. To significantly enhance
the environmental conditions of the Everglades, DECOMP will
provide a continuous flow of clean water at the northern reaches
of WCA-3A and an ecologically robust pathway for this flow
across both the central and southern
What is the DAMP? DAMP is a science-based, cooperative, multi-agency plan for combining data mining, historical analysis, physical models, and evaluation tools for finding the best restoration design for the DECOMP project without compromising water supply or flood control. It is a common sense, fiscally responsible pilot study to address Section 601(h)(3) in WRDA 2000, which states that CERP will use Adaptive Management to reduce uncertainties and incorporate new information into planning, implementation and operation of the restoration effort.
What is adaptive management for
DAMP? Adaptive management can be very generally described as “learning by doing” and as such, for the DECOMP project it is an organized means of identifying and reducing key uncertainties, allowing managers to move forward in the face of limited knowledge. Several key questions for DECOMP include:
a.
How do levees and levee modifications
affect sheetflow, ridge and slough landscape structure and
function, and b. What are the differential effects of partial versus more extensive backfilling of canals on hydrology, sediment, vegetation, and wildlife?
Why was WCA-3B selected as the
site for the DAMP Physical Model? Basically, WCA-3B was selected as the site of a physical model by an interagency DAMP design team because its orientation, hydrology, and ecological history addressed the broadest range of questions with the greatest amount of scientific rigor. WCA-3B is a region of
the
What are the risks associated
the DAMP? DAMP could be perceived by the public as a delay and lack of commitment to DECOMP by the Corps and the District. There could be cries from concerned citizens that the Corps “already knows enough” and that the Corps can proceed with DECOMP “by just restoring the natural hydrology.” There is some truth to these claims and that is why the Corps has made it clear to the public and other agencies that DAMP will accelerate ecological benefits by addressing current landscape uncertainties so that DECOMP can maximize the “bang-for-the-buck.” A second risk of the DAMP is potential misuse and misinterpretation of short-term results from the 5-year physical model. The physical model for DAMP is being implemented in an environment that still includes significant constraints on hydrologic parameters such as flow and stage. Therefore, interpretation of the results of the DAMP physical model needs to take into account the known constrained environment
PROPOSED FEEDBACK ON “BOLD DECOMP” CONCEPT
The following comments are provided to the Task Force as
feedback on the proposal
presented by the Army at the September Task Force meeting to
take advantage of the
“Mod Waters” Project by exploring more aggressive options in the
Phase 1 of the CERP
Decomp component. The Army’s proposal included two central
concepts for
consideration in the initial phase of the Decomp project—an
aggressive option to open up
the Southern Everglades to sheet flow and a revised “pipeline”
approach for dealing with
“Savings Clause” requirements in South Florida. The committee
understands that if
selected for further consideration, these concepts would be
fleshed out as part of the
ongoing Decomp PIR development process and compared with other
options developed
by the Project Delivery Team (PDT). The ultimate decision (and
ROD) would occur at
the end of that full NEPA process and construction would begin
after completion of the
“Mod Waters” project.
In general, the committee believes that the proposal—as a total
package, or as separable
elements--has the potential to address important objectives that
are fundamental to
restoration of the central Everglades, including:
•
Enhancement of sheet flow and ecological connectivity among
Water
Conservation Areas and Everglades National Park.
•
Restoration of a more natural capacity to handle extreme
high-water events
•
Improved capability and flexibility for conveyance of water from
north to south
•
Improved management flexibility to deal with high lake stages
and reduce
damaging discharges to the northern estuaries
The committee discussed and received feedback from agency staff
and private sector
stakeholders on a wide variety of topics and issues. Some of the
feedback was broadly
applicable to any Decomp option and would be considered by the
PDT in its analysis of
all the Decomp options. Several key issue areas are unique to
this proposal and would
require careful analysis during the PIR development process.
These primary issue areas
are:
A Issues with the pipeline
1. Water Quality issues – water entering the pipeline will
likely be of relatively
poorer quality than water that currently exists in wellfields
and canals in the
area where the pipe would discharge.
•
Treatment to satisfy “Savings Clause” requirements for wellfield
recharge
and water supply
•
Treatment at the end of the pipeline, including land
requirements, to
protect downstream natural areas--both wetlands and estuaries
•
Potential impacts to water quality caused by the pipe, such as
low oxygen
concentration
2. Water budget issues – it is unclear how much water is
available and how it
would be distributed at the northern and southern end of the
pipeline.
•
Water quantity assumptions at the northern end of the pipe and
implications for pipeline sizing
•
Wet season and dry season scenarios for distribution of water
•
Ultimate fate of water delivered by the pipeline
•
Satisfy savings clause requirements with respect to flood
protection,
particularly during wet season, e.g. C-6 basin
3. Pipeline Alignment issues
•
Impact of alignment on ground water flows, particularly in South
•
Other alignments should be considered, e.g. New River canal
4. Pump station issues
•
Unique air and water quality issues in middle of the Everglades
•
O&M costs—seek energy efficient approaches
B Issues with the proposal to open-up the
southern part of the system
1. Sequencing issues
•
Ensure enough water is available to avoid “over-draining” the
system
•
Improved seepage management along the L30 & L31N must be in
place
•
Integration with DAMP to maximize learning
•
Integration with other CERP projects and Mod Waters
2. Potential Environmental impacts
•
“Tree island” concerns
•
Endangered Species concerns and potential conflict with critical
habitat
C Level of support and affordability
1. Level of support?
2. Can we afford it?--$1-3 billion for pipeline, $xx million for
southern
3. What other projects would have to slip?
4. Local sponsor concern and input.
The following feedback and issues were provided to the
committee. Some apply to any
Decomp, Phase 1 proposal. They are grouped into seven broad
areas and all will require
careful consideration and analysis.
Impacts to Natural Resources
•
water diversion from Biscayne Bay or other natural areas should
be avoided or
compensated
•
seek ways to promote the recovery of endangered species,
especially the Cape
Sable Seaside Sparrow, the Snail Kite and the Wood Stork
•
seek significant net improvement to tree islands
•
ensure appropriate quality of fill for the Miami Canal
•
goal of “Decomp” should achieve natural flow distribution across
Tamiami Trail
Water Management Issues
•
address “water budget” issues, especially in the northern part
of the system.
•
include detailed operating protocols, including operations and
conveyance
capacity of the urban canals, especially during very wet and
very dry conditions
•
analysis should quantify the reduction of water levels in Lake
Okeechobee and the
improved flows to the estuaries
•
review possible flooding impacts and increased need for seepage
management,
especially in the L-30 and C-6 basins
•
review impacts from the C 139 basin
Recreation Issues
•
consider opportunities for substantially enhanced public access
and recreation,including current agreements for improved public
access
•
include suggestions from SAFER to save fisheries
•
seek net improvement of fishing opportunities, including
improvements in Lake Okeechobee and other facilities
•
avoid canal backfilling that is not necessary for restoration
•
seek improved hunting opportunities in WCA’s
Water Quality
•
carefully analyze source transfer issues, (water quantity and
quality) for the wellfields (e.g. treatment may be needed near
wellfields, and potential other locations as well.)
•
water quality issues are more substantial than nutrient
concentrations and drinking water standards, e.g. dissolved
oxygen, pathogens, microcontaminants
(EPOCs).
•
clarify STA performance expectations for water to be delivered
to WCA 3
•
assess water quality impacts and requirements in other natural
areas, e.g. Biscayne Bay and the Southern estuaries.
Design Issues
•
review potential impacts during construction
•
goal is to maintain a watershed focus and include consideration
of factors such as the effective dynamic storage of the overall
system and soil subsidence.
Interface with other Projects
•
consider how this project may reduce ASR dependency
•
closely integrate with seepage management projects along the
L-30 and L-31
•
examine implications and opportunities for the Lake Belt
component
•
ensure compatibility with Broward County WPA project
•
consider plans to expand EAA STA’s in analysis
•
consider opportunities to improve storage in Lake Okeechobee and
Biscayne Bay basins
•
consider interface with non-CERP projects such as CSOP
Science and Adaptive Management
•
the links between DECOMP, Phase 1 and DAMP need to be carefully
described, particularly in relation to the effectiveness and
timing of the two efforts
•
recognize the limits of current hydrologic and ecologic models
and consider other tools to evaluate results
•
incorporate best available tools to assess water quality impacts • Identify potential opportunities for additional learning.  |
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