2012 FDOT Mitigation Plan - Southwest Florida Water Management ...

Hydraulic and hydrologic modeling was cross-referenced with the contributing groundwater and surface water
conditions. This information resulted in the design of oligohaline marsh creation (9.9 acres) that will also displace
the twin ditches along the hammock perimeter, and freshwater marsh creation (34.3 acres). The freshwater marsh
has proposed grade elevations of -0.5 to 3.0 feet NAVD88; with ten separate freshwater marsh basins
constructed at various elevations, thus providing a range of hydroperiods within the marsh. These areas will be
primarily planted with softstem bulrush (Schoenoplectus tabernaemontani), arrowhead (Sagittaria lancifolia),
pickerelweed (Pontederia cordata), marshhay cordgrass (Spartina patens), and sand cordgrass (Spartina bakeri).
The created oligohaline marsh habitat will be graded to elevations -0.5 to 2 feet NAVD88. Plantings will primarily
include needle rush (Juncus roemerianus), sawgrass, and marshhay cordgrass.
A benefit to the created marshes at variable grading elevations is the opportunity to establish ephemeral to
obligate marsh habitats conducive to provide a range of foraging and nesting opportunities for various mammal,
amphibian, fish and avian species. Also, the design has incorporated receiving some of the treated stormwater
that discharges from Mira Lago that currently flows via ditches to Tampa Bay. The marsh will provide additional
treatment and attenuation of contributing flow and provide the opportunity for additional groundwater recharge,
further reducing some of the saltwater intrusion.
The creation of mixed forested wetland (6.6 acres) is proposed along the southeastern project boundary; graded
to elevations of 3.0 to 4.0 feet NAVD88. This forested wetland will provide a buffer from the Mira Lago
development and the constructed marsh, as well as roosting and nesting opportunities for wading birds. This
forested wetland will be planted with species representative of the coastal hydric hammock located on the
western side of the marsh; including cabbage palm, laurel oak, slash pine, red cedar, swamp bay, red maple and
sand cordgrass. For additional buffer, 2.4 acres of pine flatwood habitat will be created along the southern
boundary of the site adjacent to Shell Point Road. The area will be graded to elevations of 4.0 to 5.0 feet
NAVD88. The pine flatwoods will act as a buffer between the created wetlands and Shell Point Road, and will be
planted with cabbage palm, slash pine, and saw palmetto. Depending on the selected contractor’s proposed
schedule to haul excavated sand material from the site, the proposed flatwood area may be a temporary stockpile
location. If the stockpile has to remain for a period after the excavation is completed, the mound will be leveled,
seeded with grass, and used as an observation platform overlooking the constructed marsh. No mitigation credits
will be debited for this area until the mound is removed, final grade is achieved and proposed planting is
complete.
Forested Wetland - Coastal Hydric Hammock Enhancement (32 acres)
The coastal hydric hammock is located between the fallow fields and the mosaic of mangrove and saltwater
marsh. The coastal hammock has dominant canopy coverage of cabbage palm, with scattered slash pine, red
cedar (Juniperus virginiana), and oaks (Quercus virginiana, Q. laurifolia). Within the less dense canopy areas, the
B. pepper provides minor to moderate canopy and sub-canopy cover within the hammock. Other sub-canopy
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