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

Attachment A – Site Conditions and Conducted Activities
Freshwater wetlands are less common than saltwater wetlands within the Tampa Bay Drainage Basin, particularly
forested wetlands and freshwater systems within Pinellas County. As a result, locating appropriate freshwater
wetland mitigation opportunities within this basin is difficult. The Preserve historically had extensive problems
with exotic and nuisance species, particularly Brazilian pepper that heavily invaded all the habitat areas. Prior to
public ownership, the Preserve was operated by a private entity that planted exotic species. The Preserve staff
was diligent in it’s efforts to eradicate exotic and nuisance species, but lack of funding sources limited such
pursuits to small areas of 5-10 acres per year. In order to minimize the continuous recruitment and generation of
exotic seed sources within the Preserve, the opportunity to eradicate these species within large segments was
particularly important.
Northwest Area (65 Acres) – this area was historically a contiguous forested wetland bordered by upland
habitat. Prior to restoration commencing in 2004, the density of B. pepper varied with an average sub-canopy
cover of 30%. The pepper was much larger and provided more coverage within the wetland portion (Figure B).
The B. pepper received herbicide treatment (Garlon) and manual cutting, with most of the material removed to
the nearby mulching and incinerator facility. Herbicide treatment of B. pepper regeneration and other existing
and generated exotic & nuisance species was conducted bi-monthly through 2007, then quarterly treatments
through 2010. Supplemental tree and shrub species were planted in areas with minimal tree cover due to existing
dense pepper. Dominant tree plantings included sweetgum, red maple, popash; with pines and live oak in the
uplands. The Preserve periodically implements prescribed burns as necessary within the uplands to maintain
appropriate vegetative coverage and density. Along with the pepper eradication, grapevine is the most prolific
nuisance species controlled by hand and mechanical methods. The prescribed burning activities aid in
minimizing regeneration of the exotic and nuisance species.
Southeast Area (27 Acres) - The 57-acre hardwood swamp within the southeast section of the property is
partially utilized for FDOT mitigation, with the western half of the swamp’s enhancement (30 acres) designated to
provide mitigation for six acres of wetland impacts associated with the construction of a Lowe’s Department Store
in the vicinity. This hardwood swamp in Preserve is one of the largest forested freshwater wetland habitats within
peninsular Pinellas County, which requires the system provide more wetland and wildlife benefits and functions
than would be expected of a similar system in a less congested urban setting. This wetland receives stormwater
flow from the contributing basin which is high density residential. The wetland treats stormwater before flowing
into Lake Maggiore. During high water conditions, the lake overflows into this wetland, providing even more
opportunity for water quality treatment and flood attenuation.
Due to the muck and seasonal high water conditions of this swamp, it was necessary to mechanical eradicate
and remove the B. pepper during dry season periods. Hydraulic dredging of lake bottom sediments were also
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