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HomeMy WebLinkAboutexhibit attachmentEATTACHMENT E Project Report PROJECT REPORT CLASS I PERMIT APPLICATION NO. CC03-245 (CITY OF MIAMI / FLAGSTONE ISLAND GARDENS, LLC APPLICATION FOR A CLASS 1 PERMIT TO DREDGE APPROXIMATELY 15.8 ACRES OF SUBMERGED BAY BOTTOM FOR THE CREATION OF A 50 SLIP MEGA YACHT MARINA LOCATED ON THE WEST SIDE OF WATSON ISLAND IN THE CITY OF MIAMI, A REQUEST FOR VARIANCES FROM SECTION 24-59.1 OF THE CODE OF MIAMI-DADE COUNTY, FLORIDA TO ALLOW FOR THE PLACEMENT OF NON -WATER DEPENDANT FIXED STRUCTURES OVER TIDAL WATERS AND ACCEPTANCE OF A RESTRICTIVE COVENANT RUNNING WITH THE LAND IN FAVOR OF MIAMI DADE COUNTY) DATE: AUGUST 2, 2004 City of Miami/ Flagstone Island Gardens, LLC CC03-245, Page 1 Staffs recommendation of approval for the above -referenced permit application is based on the applicable evaluation factors under Section 24-58.3 of the Code of Miami -Dade County, Florida. The following is a summary of the proposed project with respect to each applicable evaluation factor: 1. Hydrology - The proposed project will not negatively affect existing patterns and/or volumes of flow in Biscayne Bay adjacent to the main and terminal pier arms, as well as the marginal dock of the mega -yacht docking facility. 2. Water Quality - The proposed project will not adversely affect surface or groundwater quality. The applicants shall be required to install turbidity curtains and shall monitor for the presence of turbidity in the mixing zones adjacent to the project during construction to minimize potential water quality impacts resulting from turbidity. All operations shall be temporarily suspended if turbidity exceeds background levels, and will not resume until turbidity levels return to background. If the turbidity cannot be contained by the proposed turbidity measures, the applicants shall provide an alternative turbidity plan to ensure compliance submit tufwater quality rbidity monitor eportsrds on a periodic ct to basisapproval by DERM. The applicants shall basis as required by DERM. 3. WellfieldslWater Supply/Aquifer Recharge - The proposed project is not located within a wellfield, water supply or aquifer recharge area. ' 4. Aesthetics - The applicants are proposing a fifty (50) slip mega yacht marina. The nearby uses include the Port of Miami and the Miamarina at Bayside. The applicants are proposing several non -water dependant structures such as planters, canopies, and pylons with statues that may negatively affect views of the Bay from the uplands. However, the applicants propose to provide public access to -the upper level of the docking facility. 5. Public Health - The proposed project will not adversely affect the public health. 6. Historic/Archaeological Values - The proposed project is located in the vicinity of Miami's oldest marina. However, the project e�te>not has been treceived adversely from the historic Sta#e or archaeological values. Specifically, a I Historic Preservation Office indicating that this area does not contain any resources of historic and/or archeological significance. However, in the event that artifacts of historical and/or archeological significance are found, the applicant shall notify the City of Miami Archeologist prior to recommencing work. 7. Air Quality - The proposed project is not expected to significantly affect air quality. City of Miami/ Flagstone Island Gardens, LLC CC03-245, Page 2 8. Marine and Wildlife Habitats — The proposed project includes dredging a total of approximately 15.8 acres of submerged Bay bottom that provides habitat for a variety of marine flora and fauna including. areas containing seagrasses, macro algae, hard bottom/sponge habitat, and benthic infaunal communities. The project will result in the elimination of approximately 15.8 acres of Bay bottom designated as habitat for Johnson's seagrass (Halophila johnsonii), a Federally Listed Threatened Species. In order to mitigate for the removal of 1.92 acres of seagrass resources, the applicants propose to create and plant 5.76 acres of seagrass habitat in Biscayne Bay. Creation of seagrass habitat shall be accomplished by filling a formerly dredged area of the Bay to a shallower depth, and then capping it with clean sand to support seagrass growth. To mitigate for the removal of benthic resources such as sponges and corals, the applicants propose to create 3.62 acres of hardbottom/sponge habitat. This will be accomplished by partially filling a formerly dredged area of the Bay and capping it with a coarse material suitable for the growth of a hard bottom/sponge community. In addition, approximately 0.53 acres of vertical ledge, 2.93 acres of macro -algal habitat, 0.13 acres of sponge and coral habitat located on the existing bulkhead, and 6.93 acres of benthic infaunal habitat will also be impacted as a result of the proposed project. The applicants have proposed to mitigate for these impacts by providing 0.56 acres of onsite habitat through the placement of 2439 cubic yards of limerock riprap boulders under the proposed dock structure, and by providing 5.89 acres of offsite habitat through the placement of 25,670 cubic yards of limerock riprap boulders at an approved artificial reef site in Biscayne Bay. In addition to the above mitigation, the applicants shall also be relocating coral and sponge resources found throughout the site to an area of similar light and depth regime located immediately to the north of the proposed project area. 9. soils — The proposed project will remove 217,000 cubic yards of benthic soils during dredging for the marina. Impacts to benthic communities will be mitigated as described in Section 8 above. Approximately twenty-five (25) percent of the submerged soils will be utilized on the uplands as fill. This dredged material has been certified by the soils expert as suitable material which is free from toxic pollutants and shall be required to meet the definition of clean fill as defined in Chapter 24 of the Code of Miami -Dade County. 10. Flora — The proposed project will eliminate 1.92 acres of existing seagrass communities, which include, Halodule wrightii, Halophila decipiens, Thalassic testudinum and Halophila johnsonii. In addition, 2.93 acres of diverse macroalgae communities, including numerous species of red, green and brown algae are located within the project area. DERM staff has documented no less than seventeen (17) different species of macro -algae at the proposed project site. The elimination of these resources shall be mitigated as described in Section 8 above. City of Miami/ Flagstone Island Gardens, LLC CC03-245, Page 3 11. Fauna — The proposed project will result in the elimination of approximately 3.5 acres of hardbottom/sponge community. In order to mitigate for the Toss of this habitat, the applicants are proposing to create approximately 3.62 acres of hardbottomisponge habitat by filling an existing dredge hole to an elevation suitable for sponges to grow. In addition, the proposed project will result in the elimination of an additional 0.53 acres of fish habitat provided by a vertical ledge adjacent to the Port of Miami Turning Basin and the Intracoastal Waterway (ICW). These impacts shall be mitigated as described in Section 8 above. In addition to several species of fish including, but not limited to, grouper, snapper, tarpon and grunts, numerous species of invertebrates including, but not limited to lobster, stone crabs, sponges, anemones, bi-valves, crustaceans and coral exist at the project site. 12. Rare, Threatened and/or Endangered Species — The project is located along the west side of Watson Island and is bordered by Government Cut, the Port of Miami Turning Basin, and the Intracoastal Waterway (ICW). Although this area of the Bay is not designated as Essential Manatee Habitat, the West Indian Manatee (Trichechus manatus) does utilize this area. Therefore in order to prevent an increased risk to the West Indian Manatee, the Miami -Dade County Manatee Protection Plan (MDCMPP) recommends this area of the Bay for the expansion and creation of docking facilities for large vessels (over one -hundred (100) feet in length) which generally travel outside of Biscayne Bay. The Plan also recognizes and authorizes continuation of existing uses. The applicant is requesting approval for a fifty (50) slip mega yacht marina, which is generally consistent with this recommendation. However, the applicants have also expressed a desire for mooring of a limited number of smaller vessels. In order to maintain consistency with the Manatee Protection Plan, and allow continuation of an existing use at the site, this approval shall authorize mooring of up to a total of fifty (50) vessels, with a limit of no more than twenty-three (23) power vessels Tess than one hundred (100) feet in length to be moored at this facility at any one time. Of the maximum allowable of twenty-three (23) powerboats Tess than one -hundred (100) feet in length as measured at the waterline, not more than two (2) shall be water taxis, four (4) shall be commercial fishing or diving charter boats, and three (3) shall be marina service vessels. This restriction shall not apply to sailboats equipped with auxiliary motors, or to non -motorized vessels. In order to ensure compliance with this condition of the approval, the City of Miami has proffered the attached covenant as part of DERM's Class I Permit requirements. DERM shall require the acceptance of this covenant running with the land in favor of Miami -Dade County to ensure that no more than twenty-three (23) power vessels less than one hundred (100) feet in length are moored at the subject property at any one time. Therefore, no unacceptable adverse impacts to the West Indian Manatee are anticipated. Furthermore, for the purposes of manatee protection during the construction phase of the project, specific conditions City of Miami / Flagstone Island Gardens, LLC CC03-245, Page 4 shall be included in the Class I Permit that require the implementation of standard manatee protection measures including, but not limited to, the placement of fenders to provide a four (4) foot standoff. A Marine Facility Annual Operating Permit (MOP) shall also be required and shall be issued for a maximum use of 50 vessels. The project site is located in an area of the Bay designated as critical habitat for Johnson's seagrass (Halophila johnsonii), a State and Federally Listed Threatened Species. The applicants propose, to eliminate 15.8 acres of critical habitat for Johnson's seagrass. However, during DERM staff assessments of the proposed project site, less than ten individual Johnson's seagrass shoots were observed at the site. 13. Natural Flood Damage Protection - The proposed project is related to an overall upland site development plan which will incorporate a stormwater drainage system that shall provide adequate surface water drainage and flood damage protection. The permit shall require that the cap of the new seawall shall be a minimum of six (6) inches above the finished grade and the uplands shall be sloped landward to prevent positive stormwater drainage. 14. Wetland Values - The proposed project will not result in any net loss of wetland values in Miami -Dade County. 15. Land Use Classification — Pursuant to Section 24-58.2(II)(A)(7), Code of Miami - Dade County, Florida, a substantiating letter shall be submitted by the applicants stating that the proposed project does not violate any zoning laws. Said. letter shall be submitted pending approval by the Board of County Commissioners and prior to issuance of the Class I Permit. 16. Recreation - The proposed project does not conflict with the Miami -Dade County_ Comprehensive Development Master Pian and Biscayne Bay Management Plan recreation elements. 17. Other Environmental Values Affecting the Public Interest — The City of Miami (one of the applicants) owns all of the submerged lands involved in construction of the proposed 50-slip mega -yacht marina. The submerged lands were originally deeded to the City of Miami by the State of Florida Board of Trustees of the internal Improvemwnt Trust Fund (BOT) with a requirement that these lands be used for the public purposes only. However, the applicants have received approval from the State of Florida BOT to modify the deed restrictions that require the use of the lands for public purposes only. City of Miami / Flagstone Island Gardens, LLC CC03-245, Page 5 18. Standard Construction Procedures, Practices and Performance Standards - The proposed project complies with the construction practices and performance standards set forth in: a) Miami -Dade County Public Works Manual (Section D-5) b) Biscayne Bay Management Plan 19. Comprehensive Environmental Impact Statement (CEIS) - The proposed project will not result in significant adverse environmental impacts in the opinion of the Director. Therefore a CEIS has not been required by DERM in order to evaluate this project. 20. Conformance with All Applicable Federal, State and Local Laws and Regulations — DERM staff believes that the proposed project is consistent with the Biscayne Bay Aquatic Preserve Act, as well as other state and local laws and regulations listed below. However, a final determination on consistency with state and federal laws will be made by the respective governmental reviewing agencies. a) Biscayne Bay Aquatic Preserve Act b) Federal Endangered Species Act (US Fish & Wildlife Service) c) Florida Department of Environmental Protection Regulations d) United States Clean Water Act (Army Corps of Engineers Permit is required) 21. Conformance with the Miami -Dade County Comprehensive Development Master Plan (CDMP) - In the opinion of DERM, the proposed project is consistent with the CDMP. The following is a summary of the proposed project as it relates to the CDMP: LAND USE ELEMENT I: Objective 2/Policv 2A - Level of Service. All other relevant Miami -Dade County departments have generically approved this category of proposed projects as consistent with the Miami -Dade County Concurrency Ordinance. Objective 3/Policies 3A, 3B, 3C - Protection of natural resources and systems. — The proposed project is consistent with the Coastal Management Elements of the County's CDMP and the project is not related to the development in the East Everglades. TRANSPORTATION ELEMENT II City of Miami / Flagstone Island Gardens, LLC CC03-245, Page 6 Aviation SubelementlObiective 9 - Aviation System Expansion - There is no aviation element to the proposed project. Port of Miami River Subelement/Objective 3 — The proposed project is not located in the Miami River. CONSERVATION, AQUIFER RECHARGES AND DRAINAGE ELEMENT IV: Objective 3/Policies 3A, 3B, 3D - Wel!field protection area protection. - The proposed project is not located within a wellfield protection area. Objective 3/Policv 3E - Limestone mining within the area bounded by the Florida Turnpike, the Miami-Dade/Broward Levee, N.W. 12 Street and Okeechobee Road. - The proposed project is not located within this area and does not include limestone mining. Objective 4/Policies 4A, 4B, 4C - Water storage, aquifer recharge potential and maintenance of natural surface water drainage. - The proposed project will not adversely affect water storage, aquifer recharge potential or natural surface water drainage. The applicant is required to obtain a drainage permit to ensure that these objectives are met. Objective 5/Policies 5A, 58, 5F - Flood protection and cut and fill criteria. — The proposed project does not compromise flood protection and does not include 'cut and fill activities. , Objective 61Policv 6A - Areas of highest suitability for mineral extraction. - The proposed project is not located in an area proposed or suitable for mineral extraction. Objective 61Policv 6B - Guidelines for rock quarries for the re-establishment of native flora and fauna. - The proposed project is not located in a rock quarry. Objective 61Policv 6D - Suitable fill material for the support of development. — The proposed project involves the removal of suitable fill for the support of development. Specifically, approximately 50,000 cubic yards of the dredge spoil will be used for the upland development. Any spoil used on the uplands will comply with the criteria for clean fill and with this policy. Objective 71Policv 7A - No net Toss of high quality, relatively unstressed wetlands. — The proposed project is not located in high quality, relatively unstressed wetlands and therefore this objective is not applicable to the proposed project. Objective 9/Policv 9A - Protection of habitat critical to Federal or. State -designated threatened or endangered species. — The proposed project is located in Critical Habitat for Halophila johnsonii (Johnson's seagrass), a State and Federally designated Threatened City of Miami/ Flagstone Island Gardens, LLC CC03-245, Page 7 Species of seagrass. The proposed project will result in the elimination of approximately 15.8 acres of area designated as critical habitat for Johnson's seagrass. In addition, the proposed project is located in an area the may be utilized by the West Indian Manatee (Trichecus manatus). The proposed project is not expected to result in adverse impacts to this endangered species provided standard manatee protection measures are implemented. Said standard manatee protection measures shall be implemented during construction and the facility shall be limited to a maximum number of powerboats less than one -hundred feet in length as measured at the waterline that may be moored at the facility consistent with recommendations in the Miami -Dade County Manatee Protection Plan, and as described in number 12 above. Objective 9/Policies 9B & 9C — Protection of habitat critical to federal and State designated threatened or endangered species of birds — The proposed project will not affect the nesting, roosting, and feeding habitats or rookeries for threatened species of birds. COASTAL MANAGEMENT ELEMENT Vil: Obiective 1/Policy 1A - Tidally connected mangroves in mangrove protection areas — The proposed project is not located within a designated "Mangrove Protection Area". Objective 1/ Policy 1 B - Natural surface flow into and through coastal wetlands. — The proposed project is not located in or near coastal wetlands and thereforewill not affect natural surface flow into and through coastal wetlands. Objective 1/ Policy 1C - Elevated boardwalk access through mangroves. - The proposed project does not involve access through mangroves. Objective 1/Policy 1 D - Protection and maintenance of mangrove forests and related natural vegetational communities. - The proposed project does not involve work in mangrove forests or related natural vegetational communities. Objective 1/Policy 1 E - Mitigation for the degradation and destruction of coastal wetlands. Monitoring and maintenance of mitigation areas. — The proposed project will not result in the degradation or destruction of coastal wetlands. Objective 1/Policy 1 G - Prohibition of dredging or filling of grass/algal flats, hard bottom or other viable benthic communities except as provided for in Section 24-58, of the Code of Miami -Dade County, Florida. — The proposed project involves the dredging of grass/algal flats, hardbottom, and viable benthic communities. However, pursuant to Section 24- City of Miami / Flagstone Island Gardens, LLC CC03-245, Page 8 58.3(B)(3), the proposed project involves dredging to accommodate mega -yacht vessel drafts requiring water depths ranging between 18 feet and 25 feet NGVD. Impacts to grass/algal flats, hard bottom or other viable benthic communities as a result of the proposed dredging will be mitigated as described in number 8 above. Objective 2/Policies 2AL 2B - Beach restoration and renourishment objectives. - The proposed project does not involve beach restoration or renourishment. Obiective 3/Policy 3E, 3F - Location of new cuts and spoil areas for proper stabilization and minimization of damage from tidal currents and wave scour. — The proposed project does not involve new cuts, permitted emergent spoil areas or unconsolidated shorelines. Objective 5/Policy 5B - Existing and new areas for water -dependent uses. — The proposed project involves the reconstruction and expansion of an existing water dependent marina into a mega yacht marina. Objective 5/Policy 5D - Consistency with Chapter 33D, Miami -Dade County Code (shoreline access, environmental compatibility of shoreline development) — The proposed marina and upland development project has been reviewed by and received approval from the Shoreline Development Committee. Obiective 5/Policy 5F - The siting of water dependent facilities. — The proposed project does not involve the siting of a new water dependant facility, but rather the reconstruction and expansion of an existing water dependent facility. The proposed project will result in the destruction of seagrass and hardbottom communities which is not recommended in Section i)(c) of this policy. However, the applicants have proposed to mitigate for these impacts as described in number 8 above. In addition the project is located immediately adjacent to Government Cut which provides deep water access to vessels using this docking facility as recommended in Section ii)(a) of this policy. The applicants have also proposed to provide visual access to the docking facility to preserve its existing public use. Objective 6/Policy 6E — Water dependant fixed or floating structures — The proposed project involves the renovation and expansion of an existing water dependant facility. However, the applicants also propose to include some non -water dependant fixed structures on the piers. This includes installation of 960 linear feet of planters, canopies over the terminus of the second level, awnings, storage closets, vessel fueling service lines and two 70-fool high pier pylons with decorative statues on top. Section 24-59.1 prohibits the installation of non -water dependant fixed structures. However, the applicants are seeking variances from this section of the Code to authorize placement of these non -water dependent fixed structures on the piers. City of Miami / Flagstone Island Gardens, LLC CC03-245, Page 9 Objective 6/Policv 6F — Advertisements or signs over tidal waters — The proposed project will not have any advertisements or signs over tidal waters 22. Conformance with Chapter 33B, Miami -Dade County Code (East Everglades Zoning Overlay Ordinance) - The proposed project is not located within the East Everglades Area. 23. Conformance with Miami -Dade County Ordinance 81-19 (Biscayne Bay Management Plan) - The proposed project is consistent with the Biscayne Bay Management Plan. 24. Consistency with Miami -Dade County Criteria for Lake Excavation - The proposed project does not involve lake excavation. 25. Municipality Recommendation -- Pursuant to Section 24-58.2(II)(A)(7), Code of Miami -Dade County, Florida, a substantiating letter shall be submitted by the applicant stating that the proposed project does not violate any zoning laws. Said letter shall be submitted pending approval by the Board of County Commission and prior to issuance of the Class I Permit. 26. Coastal Resources Management Line - A coastal resources management line was not required for the proposed project, pursuant to Section 24-58.2(ll)(A)(10)(b) of the Code of Miami -Dade County, Florida. 27. Wetland Fill Limits - The proposed project does not involve the placement of fill in wetlands as defined by this objective. The proposed project was also evaluated for compliance with the minimum required standards contained in Section 24-58.3 (B), (C), and (D) of the Code of Miami -Dade County, Florida. The following is a summary of how the standards relate to the proposed project: 24-58.3 (B) Dredging and/or Filling for Class I Permit - The proposed dredging for the project is consistent with Section 24-58.3(B)(3) which allows for the minimum necessary dredging for the creation and maintenance of a marina. City of Miami / Flagstone Island Gardens, LLC CC03-245, Page 10 24-58.3 (C) Docks and Piers for Mooring Purposes - The proposed project involves dredging to between — 18 feet and — 25 feet NGVD. Minimum water depths required by Section 24-58.3(C) requires that no permit be issued for the proposed work unless adequate water depth exists. Vessels utilizing the proposed marina shall have a maximum draft of 15 and 22 feet at Mean Low Water respectively, 24-58.3 (D) Clean Fiil In Wetlands - The proposed project does not involve the placement of fill in wetlands. SUMMARY BASED ON THE FOREGOING, IT IS RECOMMENDED THAT A CLASS I PERMIT BE APPROVED. IL de 14efty ';Manager Coastal Resources Section Molly Asser Environ = tal Resources Project Supervisor Coastal Resources Section Flagstone Island Gardens Mega -Yacht Harbor Submerged Aquatic Vegetation Mitigation Plan Revised July 14, 2004 PURPOSE The purpose of this mitigation plan is to provide adequate in -kind compensation for unavoidable losses to seagrass habitat function due to dredging at the Flagstone Island Gardens Mega -Yacht Harbor Project site ("Project"). The preferred Project alternative requires dredging ranging between approximately -18 and -25 feet NGVD to accommodate marina basin mega -yacht drafts. As reported by the marine market and design consultant for the Project, Brandy Marine, these depths are essential for Island Gardens to be a functional and economically viable mega - yacht harbor. Seagrass Resources: Seagrass species found within the boundaries of proposed dredging include Halodule wrightii (shoal grass), Halophila decipiens (paddle grass), and Thalassia testudinum (turtle grass), from depths ranging between —6 feet and —16 feet NGVD and average densities of approximately 35% (see revised permit sketch sheet number 2 dated 4/14/03). The goal of the compensation project is to offset the losses in seagrass habitat by restoring seagrass habitat with similar species to those impacted with an equal or greater value of services provided. Reports from the Miami -Dade County Department of Environmental Resources Management (DERM) indicate that a few leaves of Halophila johnsonii (Johnson's seagrass) are present at the Project site (based on the site inspection on August 21, 2003, and subsequent dives in October 2003). However, a Johnson's seagrass survey utilizing the techniques outlined in the "National Oceanic and Atmospheric Administration's Recovery Plan for Johnson's Seagrass, Recommendations for Sampling Halophila johnsonii at a Project Site (Appendix III)" was conducted on August 25 and 26, 2003 by Coastal Systems International and no Johnson's seagrass was observed. The proposed Project is within designated critical habitat for Johnson's seagrass, but this area is not critical to the continued viability of the species due to its isolated configuration and lack of primary constituent elements necessary to support a significant Johnson's seagrass community. The proposed mitigation project, also within the designated critical habitat, will provide higher quality habitat for Johnson's seagrass than that Lost based upon seagrass functions provided. Macroalgae Resources: Both Chlorophyta (green algae) and Rhodophyta (red algae) have been identified attached to the submerged lands and the bulkhead at the Project site. Typical green algae found' at the site included scattered communities of Calerpa, Halimeda, Udotea, Acetabularia, and Avrainvilla. More difficult to identify were the red algaes, but appeared to be Wrangelia spp., and Dasya spp. To quantify the limits of macroalgae coverage, surveys were conducted along 50-foot transects perpendicular to the bulkhead. Coverage was sparse to medium throughout most of the Project area (see revised permit sketch sheets 2 and 3 for additional location and quantity details). Total area of macroalgae on substrate proposed to be 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 2 impacted was calculated to be approximately 790 square feet at the time of the survey; the coverage appears to be highly variable. The bulkhead also contains communities of macroalgae (both red and green algae). Macroalgae coverage of the bulkhead is estimated at 35 percent. Total area of macroalgae habitat is approximately 3,500 square feet on the bulkhead. Mitigation for macroalgae impacts on the bulkhead and associated with the sponge -dominated community onsite are addressed in the revised "Benthic Community Mitigation Plan". Mitigation for macroalgae impacts associated with areas containing seagrass are addressed below. DESCRIPTION OF THE SEAGRASS MITIGATION PROJECT Mitigation Quantity & Quality: The compensatory mitigation project will focus on restoring the functional services of the impacted area of seagrass habitat. The original area of seagrass coverage surveyed in May 2003 was approximately 0.94 acre. However, the establishment of paddle grass at the Project site in late summer increased total coverage to 1.92 acres (including seagrass observed during survey work in the Intracoastal Waterway on October 24, 2003). The concepts provided in Guidelines for the Conservation and Restoration of Seagrasses in the United States and Adjacent Waters (Fonseca et al., 1998), the Habitat Equivalency Analysis (HEA) Methodology, as well as the Uniform Mitigation Assessment Method (UMAM) adopted by the Florida Department of Environmental Protection (see attached HEA and UMAM worksheets) are being used to size the restoration project. There will be loss of seagrass habitat between the time when the impact area is dredged (i.e. the seagrass habitat at the Project site is lost) and the restored seagrass habitat is of functional equivalency to the lost habitat. This is referred to as an interim loss of habitat. A higher quality habitat with a greater range of seagrass functions will be restored at the mitigation site than that impacted. This plan proposes in -kind mitigation at a 3.5:1 ratio, which is slightly higher than the UMAM results presented below, based on the conservative estimates of time used to reach function greater than or equal to that lost at the impact site (results described below). The HEA methodology recommended a lesser mitigation ratio (results described below). Therefore, approximately 5.76 acres of seagrass habitat (3:1 ratio) will be restored. Consistent with the South Florida Water Management District recommendations, 0.96 acres (0.5:1 ratio) will be out -of -kind mitigation, for a total mitigation ratio of 3.5:1 (see the revised Benthic Community Mitigation Plan for additional information on the out -of -kind mitigation proposed for impacts to the seagrass community). Results of HEA and UMAM Analyses: The location of seagrasses at the Project. site is provided on Sheet 3 (of 22) of the permit sketches. The seagrasses at the Project site includes 0.94 acre of mixed density shoal grass (Halodule wrightii) and 0.98 acre of medium to sparse density (21-40% coverage) paddle grass (Halophila decipiens). A small amount of turtle grass (Thalassia testudinum) was found and the acreage is included in the 0.94 acre. The mixed density shoal grass was found in patches with the following densities: 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 3 • sparse (0-20% coverage) • medium to sparse (21-40% coverage) • medium (41-60% coverage) • medium to dense (61-80% coverage) Calculation of Sufficient Mitigation Area: Two methods are used to confirm calculation of sufficient mitigation area: the Chapter 62-345, Uniform Mitigation Assessment Method, F.A.C. (UMAM) and the Habitat Equivalency Analysis (HEA) (NOAA 2000). 1. A conservative approach to using the UMAM (see attached calculation spreadsheets) is used where the subjectivity of the rule was removed by using a range of scenarios that are very conservative given the quality of the seagrass habitat at the Project site. Many factors in the UMAM scoring could negatively impact the scoring of the seagrasses at the Project site, These include the following considerations: • .500(6)(a) Location and Landscape Support — The seagrass area on the shoal at the Project site represents an isolated seagrass area as opposed to a seagrass bed that has connectivity to a larger bed or an area of shoreline seagrasses. • .500(6)(b) Water Environment — The seagrass area at the Project site represents an area that is at a depth that is too deep for dense growth of seagrasses. • .500(6)© Community Structure — The seagrass area at the Project site is either generally sparse or medium (0-60% coverage) and as such does not provide optimum habitat. In addition, as stated above for location and landscape support, the area is isolated and as such does not provide optimum habitat. In spite of these considerations, the seagrass is scored using a very conservative range between optimum and moderate (10 — 7). This results in a combination of potential functional loss categories from high/high to low/low. A conservative time factor is used that indicates that we will be able to construct a seagrass bed of comparable density within 6 — 10 years of the project. This is a conservative estimate because past projects indicate that a shoal grass bed should establish itself within 5 years or less from planting. A conservative risk factor of 2 (moderate risk) is used because seagrass projects, if planned correctly, have proven to be successful. Using these conservative factors, the UMAM estimate for adequate mitigation area is between 4.80 and 4.84 acres (2.5:1 ratio calculated versus the proposed 3:1 ratio for this Project). 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 4 2. HEA is used in calculating sufficient replacement area to compensate for damages in a natural resource damage assessment. Again, a conservative approach is used to estimate the area that would replace the interim losses of seagrass habitat between the time of loss and the time of functional replacement. This time period is estimated to be 10 years and considers that the mitigation project will begin immediately subsequent to Project construction. The interim loss of habitat will be replaced by planting an additional 0.36 acre of seagrasses to the base loss (1.96 acres). The HEA provides an estimate that 2.32 acres of seagrass are required for mitigation (1.2:1 ratio calculated versus 3:1 ratio proposed for this Project) Location of the Preferred Mitigation Site: Due to the presence of seagrass in the shallower dredge holes adjacent to the Julia Tuttle Causeway Bridge, the applicant is proposing to fill a deeper dredge hole that is absent of seagrass below the — 15 foot NGVD contour. The preferred mitigation site (mitigation area 1) is located on sovereign submerged lands, and will require a consent of use for placement of fill from the South Florida Water Management District. Mitigation Site Characteristics: Mitigation area 1 is a deep dredge hole (see the attached location map (sheet 1) for reference). This site does not contain seagrass below approximately — 15 feet NGVD. Mitigation area 1 is approximately 5.76 acres when filled to the — 5-foot NGVD contour. Mitigation area 1 contains an apparent berm established around the perimeter of the dredge hole, deep water for fill access operations, and few marine resource communities at the fill depths proposed. Note that sponge communities do exist along the edges of the mitigation site at maximum depths of-12 to —14 feet NGVD; impacts to these sponges will be avoided (see sheet 3 for approximate locations of sponge communities). Depths at the preferred mitigation site vary between —2 feet and —26 feet NGVD. Mitigation Design: The proposed design involves no direct impacts to seagrass: Cross -sections of the dredge hole are included (see sheets 5 and 6). This design fills the dredge hole completely from the bottom to approximately — 15 feet NGVD, and then slopes up and inward to a plateau at a depth of — 5 feet NGVD (see sheet 5). Fill will be placed at least three (3) feet offset from the nearest existing seagrass bed edge. Fill will also be slop l away from sponge communities to avoid direct impacts.. The slope is designed at a stable 3-foot horizontal to 1-foot vertical rise, and should support Johnson's grass, paddle grass and shoal grass. The plateau should support both shoal and manatee grasses. The volume of fill required is approximately 125,000 cubic yards. Pursuant to discussions with DERM staff, this project design has proven to be successful at a seagrass habitat restoration site north of the Julia Tuttle Causeway, adjacent to Biscayne Point and the 79th Street Causeway. A draft report that summarizes the successes and challenges of Biscayne Bay seagrass restoration projects (including the DERM project) is currently being prepared by Mr. Gary Milano and Mr. Don Deis for publication; this draft report and a summary table is enclosed for your review. This report confirms that the design of the Island Gardens mitigation project is consistent with other successful seagrass restoration projects in Biscayne Bay. 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 5 Sediment Source: The interior of the dredge hole at the mitigation area will be filled with sediment excavated from the submerged lands adjacent to the Island Gardens Project site and/or another suitable fill source. Sediment will be stockpiled during marina basin excavation onsite and either transported via truck to a suitable barge loading facility adjacent to the dredge hole, or loaded directly onto a barge at the Project site and transported north to the mitigation site. The geotechnical boring profiles submitted with the permit application indicate that the submerged lands to be dredged onsite largely consist of dredge spoil containing both silt, sand and limestone down to depths of approximately -; 25 feet NGVD. A minimum of one foot of sand (less than 20 percent fines passing the 200-sieve analysis), likely aragonite, containing characteristics similar to sediment supporting adjacent existing seagrass beds will be used to cap the fill, providing suitable substrate for seagrass growth. Method of Transport: As stated previously, excavated material may be transported by truck to a barge loading facility adjacent to the dredge hole, or placed on a barge adjacent to the Island Gardens Project site and transported north. The preferred option will be determined upon confirmation of and coordination with a licensed marine contractor. The draft of the fully loaded vessel will not exceed 8 feet. Access to the mitigation site exists from the east, with water depths exceeding barge draft (see sheet 7 for barge track plan). Turbidity Management and Monitoring: Turbidity will be controlled by driving temporary wood piles around the boundaries of the dredge hole at the mitigation site, and enclosing the dredge hole with a double -walled turbidity curtain. The transport barge will be moored inside of the turbidity curtain during offloading of spoil material. Turbidity levels will be monitored by measuring the nephelometric turbidity units (NTUs) in a circular arc around the dredge hole filling operation at an approximate radius of 150 meters (mixing zone). If any turbidity compliance samples exceed background, construction activities that may be contributing suspended solids to the receiving water body will cease immediately and will not resume until corrective measures have been taken and turbidity returns to acceptable levels (compliance with Chapter 62-302, Florida Administrative Code). Donor Seagrass: Donor seagrass material will be obtained from the Island Gardens Project site. The submerged parcel at Island Gardens contains mixed and monospecific beds of shoal grass and paddle grass; a small patch of turtle grass is also present. As much shoal grass as possible from the impact area will be salvaged and transplanted. No paddle grass or turtle grass will be targeted for transplantation. At least two (2) secondary donor seagrass beds of shoal grass will be required, and are proposed to supplement the transplant efforts. Additional donor beds will be scouted, and their locations provided to the regulatory agencies if necessary. The donor beds are proposed to be located within the same vicinity as the mitigation site. See the attached location map (sheet 1) for the location of the proposed donor beds. Donor seagrass bed 1 (E-938638.18/N-546616.08) is 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 6 approximately 5.2 acres; donor seagrass bed 2 (E-935989.87/N-540225.72) is approximately 1 acre. Depths at the donor sites range between —6 feet NGVD and above. Two main species of seagrass exist within and adjacent to the donor beds — shoal grass and manatee grass; density of shoal grass is fairly consistent at 80 to 100 percent coverage. Pursuant to comments and discussions with resource agencies, donor seagrass plugs will be collected, but collection techniques will not result in the harvesting of greater than 10 percent of the overall area containing shoal grass. Approximately 80 percent of the transplant seagrass material (8,000 plugs of shoal grass) will be collected from the donor beds; only 20 percent of the shoal grass transplant material is expected to be collected/salvageable from the project site (2,000 plugs). Limiting the amount of collection to less than 10 percent within the donor sites will result in no significant impacts to the donor beds. Spacing between plugs collected at the donor sites will be equivalent to approximately 2 feet or greater. Each acre of donor material should yield .2-3,000 plugs. Collection and Transplanting Technique: Prior to commencement of dredging operations within the vicinity of the shoal grass beds at the island Gardens Project site, shoal grass will be collected utilizing a core tube to extract plug samples. Core tubes will range in size but average approximately 4 inches in diameter. The plug units will be collected in buckets/tubs on board a collection vessel. The plugs may be transported to a temporary storage area, as necessary, adjacent to the mitigation site. The plugs from the Project site may be held in nearby shallower dredge holes that range in depths of —10 to —11 feet NGVD (similar to Project site) and contain sparse seagrass communities of shoal and paddle grasses for 1 to 2 weeks during which time the dredge hole will be filled and the sediment allowed to settle. The settling rate depends on the percentage of silt in the fill material and at the bottom of the dredge hole. Initial settling rate estimates for fill containing less than 15 percent of fines passing the —200 sieve test are 1-3 weeks. Higher percentages of fine, silty soil in the fill material will result in longer settling times. Shoal grass units will also be collected at the donor seagrass beds (see location map attached). These units will be collected and transplanted the same day, utilizing a shovel and/or plug collector to collect the sample. After settlement of the mitigation site, a small shovel or similar tool will be utilized to loosen sediment along pre -established transect lines spaced at 3-feet on -center. Transects will be oriented in an east -to -west direction (spaced at 3 feet apart). Each plug unit will be planted and stabilized, The total number of plugs to be planted is approximately 10,000. Steel staples will be utilized to help anchor the seagrass plugs. Project Success Criteria and Project Monitoring: The monitoring program is designed to examine the progress of the project towards its goal of compensating for the loss of seagrass habitat at the Project site. A pre -construction survey of shoal grass will be performed within the Island Gardens Project impact area, the donor sites, and a reference site ("background areas") to 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 7 further document the species composition, density, patchiness, and other characteristics of seagrass growth. This information will be used to establish baseline conditions and confirm standards for success criteria of seagrass within the mitigation areas. Data used to date to design the mitigation project was Project site seagrass densities (average) of 35% and assumed success at the mitigation site of 60 to 70 percent cover. Since shoal grass will be planted at the mitigation site, the success criteria will be achievement of density comparable to that of a shoal grass bed located at a similar depth near the mitigation area (reference site). In addition, to ensure no long-term impacts from seagrass collection techniques are observed, monitoring will also be conducted at the donor sites. The mitigation site, reference site, and the donor seagrass beds will be monitored along random transect lines (technique discussed below). The following monitoring methods will be used at all 3 areas (with the exception of percent survival of planting units for the reference and donor sites): 1) Survival of the planting units will be recorded by measuring random subsections of the planted area. This parameter will be used to determine if additional maintenance planting may be required early (within the first 1 to 3 years) in the monitoring program. It will be difficult to discern the individual planting units when the rhizomes begin to coalesce. If and when this occurs, this parameter will be discontinued within the planting area. 2) The aerial coverage (spread and eventual coalescence) of a randomly selected number of planting units. A 1-meter square quadrat divided into 10 cm X 10 cm grids will be used for this monitoring. The number of squares containing seagrasses will be counted to estimate percentage cover. In addition, percent aerial cover will be equated to cover classes within the 1-meter 'square quadrat, based on a modified Braun-Blanquet (1932) technique (see table below). This technique is commonly used in estimating plant coverage. This technique will also be used to confirm aerial coverage over time at the other monitored sites (reference site and donor site). Cover Class Description 0 Absent ' 0.1 Solitary shoot 0.5 A few individual shoots, less than 5% (5-10 cm X 10 cm grids) cover 1 Many shoots, less than 5% cover 2 5% to 25% cover 3 25% to 50% cover 4 50% to 75% cover 5 75% to 100% cover 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 8 3) A count of the number of shoots in the above described random samples within the planting site and other monitored areas. The shoots will be counted within 10 randomly selected 10 cm x 10 cm grids within the 1-meter-square quadrat. This number will be multiplied by 10 to obtain the number of shoots per meter square. A random sampling program will be developed for monitoring of the mitigation site, reference site, and the donor sites. Success of the mitigation project will be measured by comparing the data from the planting site with similar data from the reference site. A power analysis will be performed on initial data from the Project site to determine the number of samples required for statistical analysis. Note that the mitigation site will be divided into an equal number of cells (5 or greater). It is estimated that approximately 200 quadrat measurements will be taken within the mitigation site cells (40 per cell approximately), evenly distributed, to ensure that adequate sampling coverage of the mitigation site is achieved. The quadrat measurement number will be adjusted from 200, as necessary, to achieve a reasonable statistical confidence level, Successful recovery at the donor sites will be achieved when the original plug areas (where donor transplant material was collected) are no longer distinguishable from the surrounding seagrass beds. The seagrass areas will be monitored for a period of five years. The preferred planting time is in May near the beginning of the seagrass growing season. Quarterly monitoring will be performed in the first year in August, November, February, and May. The focus of the first year will be on planting unit success in the mitigation area. If planting unit success is determined to be unsuccessful, remedial actions will be proposed (e.g., additional planting units). Biannual monitoring will be performed in years 2 through 5 or until it has been determined that success, as described above, has been achieved. Biannual monitoring will be performed in April and September, at the beginning and end of the growing season. A statistical analysis and report will be generated from data collected during each monitoring event to determine if success has been achieved. If success has not been achieved by year 5, remedial actions will be proposed. Remedial Actions - If success criteria are not met at the mitigation site, remedial actions will be taken during each stage of the monitoring cycle. Remedial actions will primarily consist of re- planting as necessary those barren areas, or those areas that did not achieve the projected growth. If re -planting does not work, additional measures will be conducted which include review of soil conditions, currents, and additional measurements (turbidity, etc) intended to provide valuable information concerning the water environment within that zone/cell of the mitigation area. All corrective actions will be coordinated with the regulatory agencies. If the remaining holes left from the plug samples do not fill in, remedial actions at the donor site will include the inclusion of a small amount of fill into any apparent plug hole remaining after the original plug sampling occurred during the mitigation project. However, it is anticipated that these holes will fill in and coalesce within 2 to 3 years from the date of collection, if not sooner. The proposed schedule for monitoring and submittal of monitoring report, assuming planting completion by August 2004, is as follows: 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 9 November 2004 — 1st report (3 months from date of planting) February 2005 — 2nd report (6 months after first monitoring period) May 2005 — 3rd report (9 months after first monitoring period) November 2005 — 4th report April 2006 — 5th report September 2006 — 6th report April 2007 — 7th report September 2007 — 8th report April 2008 — 9th report September 2008 — 10th report April 2009 — 11 th report September 2009 — 12th report Construction Schedule: The preferred mitigation construction schedule will allow for filling of the dredge hole by July 2004. Ideally, this will allow approximately 1 — 3 weeks for the fill area to settle before transplanting the seagrasses from the holding areas to the mitigation site. Note that the lower the percent of fines in the transported sediment, the faster the settling times. Seagrass transplanting is proposed to begin in late July or early August 2004. 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 10 REFERENCES Braun-Blanquet, J. 1932. Plant sociology: the study of plant communities. Reprint 1983 Koeltz Scientific Books. P.O. Box 1360, D-6240 KoenigsteinlWest Germany Damage Assessment and Restoration Program, National Oceanic and Atmospheric Administration, Department of Commerce. 2002. Habitat Equivalency Analysis: An Overview Milano, G.R. and Deis, D.R. 2004. Biscayne Bay Seagrasses and Recent Restoration Efforts (draft summary report). 201701 SAV Habitat Mitigation Plan July 14, 2004 Page 11 1kh6117ata-75Projaen,2017011Mitigatianl(04-07-14) Submerged Aquatic Vegetation Habitat Mitigation Pian.doc