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

coverage of Brazilian pepper, cabbage palm, salt-bush, wax myrtle, and saw palmetto. Small pockets of black
needle rush, cordgrass, and sawgrass are located in the interior of the hammock. North of the field is a
termperate hardwood wetland area (9 acres) with cabbage palm, slash pine, laurel oak, and ground cover of
scattered palmetto, sawgrass, and swamp fern. Brazilian pepper and lead tree have invaded this area as well. A
large mosaic of salt-marsh (14 acres) and mangrove habitat (35 acres) is located west of the hammock.
Vegetation in the marsh portion is dominated by saltwort, glasswort, and salt-grass. The mangrove portion is
dominated by white mangrove with scattered black mangrove and buttonwood. Shrub-size mangroves transition
into the marsh component. This saltwater habitat has interconnecting mosquito ditches with adjacent spoil piles
covered with Brazilian pepper. In part due to the altered hydrology from the ditching, the transition between the
hammock and saltwater habitat has generated a dense stand of Brazilian pepper (photo). Additional site
information is provided in Attachment A.
C. Brief description of proposed work: Piezometers were installed in the fallow field and routinely monitored
from 2003-2008 to evaluate the surficial groundwater conditions. To determine wetland creation design, this
information was critical to determine appropriate hydroperiods and extent of saltwater intrusion; some of which
are the result of the two large tidally-connected ditches. Commencing in 2005, the Mira Lago subdivision was
constructed east of the Bahia Beach tract. The construction design was delayed and piezometer monitoring
extended to evaluate and incorporate habitat design revisions due to changes in the contributing ground and
surface water as a result of the residential development. As a result, the fallow field will be graded to create a
dominance of freshwater marshes (34.3 acres) transitioning to oligohaline marsh habitat (9.9 acres) closer to the
forested wetland hammock, and buffered from Mira Lago by creating mixed forested wetland habitat (6.6 acres)
along the eastern perimeter of the created marsh habitat (Figures E & F). Treated stormwater that currently
discharges from Mira Lago and flows via the ditches to Tampa Bay will receive additional treatment, attenuation
and increase groundwater recharge by the construction of the created wetlands. The hammock (32 acres), saltmarsh
(14 acres), mangrove habitat (35 acres), and temperate hardwood areas (9 acres) will be enhanced with
the eradication of Brazilian pepper, however due to the potential of off-site drainage alterations, no construction to
remove the associated mosquito ditches will be conducted in these areas. The combination of constructed and
enhanced wetland habitats with different habitat features and functions will provide corridors for wildlife utilizing
the ecosystems on this tract and the adjacent public lands. Additional information is provided in Attachment B.
D. Brief explanation of how this work serves to offset the impacts of the specified DOT project(s):
Through 2011, the majority of the anticipated wetland impacts proposed for mitigation at the Bahia Beach project
include wetlands associated with long-range future expansion activities at Tampa International Airport (TIA). Due
to the close proximity to Tampa Bay and high quantity of ditched wetlands, the majority of the proposed wetland
impact areas at TIA are low quality systems. There will be future roadway proposals and associated wetland
impacts that will be evaluated for potential mitigation at Bahia Beach. The combination of various wetland creation
and enhancement activities at Bahia Beach will provide appropriate mitigation options to compensate for impacts
associated with a combination of forested and non-forested freshwater and saltwater wetland impacts. With Bahia
362