The Clean Water Coalition (CWC) of Indian River County (IRC) supports ongoing efforts to modernize the Vero Beach City Marina. As you may know, our organization presents an independent, unifying voice to protect and restore surface and ground waters in IRC, including the Indian River Lagoon (IRL). We are especially interested in helping to protect, maintain and improve water quality by modernization of the marina.
We are pleased with stipulations cited in the Florida Department of Environmental Protection (FDEP) permit to the COVB including the following:
· Use of a turbidity curtain during dredging that extends to within one foot of the submerged bottom.
· Transfer of dredged material directly to a self-contained barge for disposal at a dewatering site.
· Installation of ~130 feet of sheet pile located 2 feet waterward of the existing bulkhead.
· Transport of all construction materials to and from the site via barge and upland roadways with all tools and materials stored on the barge.
· Protection of adjacent submerged vegetation from erosion, siltation or scouring.
The above precautions were well received by the CWC. Furthermore, dredging will be to a water depth of ~10 feet; this will likely remove all muck from the Phase 1 dredging area.
We also have concerns that were not addressed in the FDEP permit. These concerns center around the five issues discussed below:
(1) Hydraulic dredging rather than mechanical dredging is the preferred dredging method
(2)Our preferred location for dewatering dredged material is a Florida Inland Navigation District (FIND) site, such as IR2 near Wabasso, rather than the city marina.
Ideally, dewatering of dredged material will be conducted at an optimum location. One dredge spoil site that has been discussed is on the east side of the city marina where an unoccupied office building stands. At this marina site, large trees and accompanying root system, proximity to a ditch to the IRL, cost of developing a small, lined dewatering site at the marina, plus a high probability for increased concentrations of nitrogen (N) and phosphorus (P) in water returned to the IRL, make the marina site unfavorable. Therefore, we encourage transfer of dredged material for dewatering to a FIND Dredge Material Management Area (DMMA) site, such as IR2, located near Wabasso, ~9 miles from the city marina. The IR2 site has been studied in detail and has the positive effect of yielding significantly decreased concentrations of dissolved N and P in water released from the DMMA to the IRL (Maglio et al., 2021, in WEDA Journal of Dredging, Vol. 19, Issue 1, pp. 1-13 https://www.westerndredging.org/journal).We also support use of a FIND site for Phase 1 because it would be the best site for dewatering dredge spoils during any future phases of marina modernization.
(3)We are concerned that contaminants may be released to lagoon waters during dredging and after the city marina has been modernized.
Releases of N and P from muck to the overlying water are found throughout the IRL. We are concerned that the 1:5 slope proposed for dredging in Phase 1 is insufficient to prevent return of muck to the dredged site. Such a shift could reinitiate muck fluxes of N and P. Therefore, we encourage the city and its contractors to revisit the choice of dredging design to limit muck return to the dredged area.
Fuel and waste from boats are the most common causes for degraded water quality in marina settings. The modernized city marina will have pump-out equipment at each slip that connects all vessels to sewer, thereby eliminating sewage discharges. Improvements at the revised fuel dock, plus pump-out requirements via a pump-out vessel for moored boats, are also valuable upgrades. To ensure that fuel and cleaning products do not enter the lagoon when boats are cleaned for dry storage, a wash-down area that captures and treats all run-off water is needed.
Adequate stormwater retention and treatment are a challenging issue at this space-limited location. The greater the expansion – the greater need for additional retention and treatment. For that reason, we recommend “right sizing” the dry storage building and other components of marina modernization. Low Impact Development (LID) techniques should be implemented such as permeable parking areas and tree preservation to absorb and treat water.
One critique from the Vero Beach community is that more boats will release more copper from antifouling paints. We suggest that the marina staff recommend off-the-shelf bottom paint with lower copper concentrations. Copper concentrations are typically higher in waters around a well-populated marina and any effort to control releases of chemical contaminants, to marina waters will be a welcomed reminder that the Vero Beach City Marina is a Florida Clean Marina (Florida Clean Marina Best Management Practices (floridadep.gov)).
(4) We request that the COVB initiate water and sediment quality monitoring during and after Phase 1 dredging.
Community concerns for contaminants can be lessened with data. We encourage the COVB to plan modest water quality monitoring during dredging to supplement required turbidity testing. We recommend analysis of water for total dissolved nitrogen (TDN) and total dissolved phosphorus (TDP) during dredging. A schedule for sampling for N and P could be set so that the party sampling for turbidity periodically samples for N and P. We also encourage annual sediment (copper) and water (N and P) analysis.
(5) County-wide mapping and mitigation of muck deposits.
The CWC also is interested in further discussion of a suggestion by the Indian River Neighborhood Association (IRNA) that the COVB consider working with IRC to develop a county-wide muck map for IRL, including adjacent tributaries and the Vero Beach City Marina. The IRNA then suggested that, over time, COVB could join IRC, FIND and the State of Florida to obtain funding for muck mitigation projects. When and where dredging is appropriate, we encourage collaboration with FIND to use one of their DMMAs. These long-term efforts parallel the multi-year modernization of the marina and help achieve a measurable reduction in nutrient fluxes, a positive environmental benefit to the lagoon.
The CWC urges the COVB to undertake the necessary marina modernization in a manner that helps protect the waters of the IRL. We appreciate discussion and input from Dr. John Trefry, a Professor Emeritus at Florida Institute of Technology. His 40-year career as a chemical oceanographer included global research activities as well as local studies of muck, dredging and water quality in the IRL (https://www.youtube.com/watch?v=BxjjOappyN8; Fox and Trefry, 2018, https://www.researchgate.net/publication/327703735; Trefry and Fox, 2021, https://www.frontiersin.org/articles/10.3389/fmars.2021.752945/full).