To: St. Lucie County Conmission October 18, 2004

From: Jeff Beal, FDEP OCAMA

RE: stabilization of Indian River Drive

These comments are hereby submitted by the FL Dept. of Environmental Protection, Office of Coastal and Aquatic Managed Areas, representing the State of Florida Aquatic Preserves Program. The Indian River Lagoon contains 7 of the state’s 41 Aquatic Preserves, including a segment from the city limits of Fort Pierce to Jupiter Inlet. Aquatic Preserves are protected because of their pristine condition and abundance of natural resources. The importance of the Indian River Lagoon cannot be overstated. The Lagoon not only contains 7 Aquatic Preserves, but also is part of the federal National Estuaries Program and holds the distinction of being the most diverse estuary in North America. Through the Feasibility Study, the southern third of the Lagoon has been selected to receive the first large-scale restoration associated with Comprehensive Everglades Restoration Program. The lagoon provides roughly $1 billion in revenue annually to its neighboring counties. Any adverse environmental impacts to the lagoon will result in a loss of that revenue to the area and a degradation of a national treasure.

The stability of Indian River Drive has been under scrutiny for some time and now has become critical due to hurricane damage. The Drive is constructed on top of the relic sand dune that was created thousands of years ago when sea level was much higher. Though this sand ridge has experienced some erosion over the centuries, it has been protected by the barrier island, the shallow lagoon adjacent, and by the numerous plants that stabilize its bank and top. Erosion has been exacerbated only in those areas where plants have been removed and, in some cases, where other less successful stabilization methods have been employed (e.g., rip-rap, seawalls, and shallow-rooted grasses). The recent storms clearly show that the areas with significant plant densities experienced the least amount of erosion. In summary, certain plants hold shorelines better than any other method. In addition, many of these plants provide habitat, sediment trapping, nutrient uptake, and primary production (leaves) for the Lagoon. Most of the work currently being conducted along the Drive has been done without any erosion control measures in place. Countless tons of sediment that were dumped down the bank were eroded into the lagoon during the passage of Tropical Storm Ivan and Hurricane Jeanne, contributing to the already high turbidity and most likely burying seagrasses.

In addition to these issues, St. Lucie County has spearheaded a recent effort to designate the Drive as a major segment of the County’s Scenic Highway. The Scenic Highway Plan, developed by numerous citizens and agencies, clearly describes the County’s intention to maintain the natural, ecological, and scenic aspects of the Drive. This Plan includes the removal of exotic plant species and the promotion of native plant species in order to improve the aesthetic and environmental features.

Stabilization of certain portions of the Drive has become critical but the measures taken to do so must not compromise all of the afore-mentioned benefits and pristine natural resources of the Indian River Lagoon. The contract plans recently offered for bid by the County are insufficient to protect the Indian River Lagoon and its natural resources and would be deemed unacceptable under non-emergency permitting. These plans allow for the complete removal (clearing and grubbing) of all existing vegetation east of the Drive and replanting of only Bahia grass, an exotic species. These plans also do not state whether or not construction activities can be conducted from the water, jeopardizing seagrasses in the Lagoon. Therefore, we propose that the County Commission adopt a resolution to protect the natural and ecological features of the Drive, its associated bank, and the Indian River Lagoon. We recommend incorporating the following measures into that resolution. These proposed measures are standard techniques currently utilized in the State of Florida.

-standard techniques of erosion control (turbidity barriers, silt fences, other BMPs) must be in place for all existing and future stabilization efforts

-the sediment that has been and will be placed along the bank and within wash outs must be compressed and capped with beach quality sand

-all construction activities shall be conducted from the landward side of the project

-existing native plants along the shore, bank, and top of slope east of Indian River Drive that are currently vertical shall be left in place and undamaged by stabilization construction

-existing native plants along the shore, bank, and top of slope east of Indian River Drive that are currently not vertical but can readily be stabilized shall be righted (placed vertical), stabilized in place, and undamaged by stabilization construction

-further stabilization shall be conducted by the planting of native species at the toe of the slope (e.g., smooth cordgrass Spartina a/tern jflora, rush Scirpus spp., red mangrove Rhizophora mangle), intermixed with rip-rap (e.g., red mangrove Rhizophora mangle, sea purslane Sesuvium spp., sea ox-eye daisy Borrichia spp., black mangrove Avicennia germinans, white mangrove Laguncu/aria racemosa, cord grass Spartina bakeri, cord grass Spartina patens), and landward of the rip-rap (e.g., sabal palm Saba/palmetto, gumbo limbo Bursera simaruba, buttonwood Conocarpus erectus, cord grass Spartina bakeri, seagrape Cocoloba uv~fera, oaks Quercus spp., saltgrass Distich/is spicata, dune sunflower He/ianthus spp., blanketflower Gai//ardia pu/che//a)

-in areas with hundreds or thousands of feet of contiguous, stable, natural shoreline, hardening (ie rip-rap) should not be used and native species should be planted

-coquina boulders shall be used as rip-rap material instead of concrete rubble. If it is not feasible to use coquina exclusively, then coquina shall be placed at the toe (from base to +3.0’ feet elevation)

-fabrics/geoweb used for stabilization above the +6.0 feet elevation contour shall be made of natural materials

-terracing shall be utilized in areas with greater than 10’ of vertical relief. Terraces shall be a minimum of 18” wide.