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%eci*lonit WAApmaca Page 10 and horizontal) will be developed and the expected mitigation requirements for this anticipated impact will be evaluated to determine if changes in the design will eliminate or reduce the impact. The total area of potentiallexpected sedimentation impact will be determined by Sector, the costs of mitigation quantified, and the approximate costs to construct this mitigation area(s) will be included in the revised Project cast estimates.. r The survey of nearshore hardbottom resources will provide the information needed to furnish the FDEP with information to document potential impacts on these resources. The extent (aria coverage) and approximate relief of exposed rock outcrops shall be • determined by a combination of digitizing County -furnished color positive aerial photographs and diver transects over the hardbottom structure to determine reef character and vertical relief. Diver transects witl provide mapping and representative photographs of relief and character. Video mapping will verify vertical relief and provide representative images of the exposed rock features for analysis and color overlay mapping of hardbottom features for presentation in the report. Subsequent to determining the locations and character of the hardbottom resources located along the Project beachfill areas, ATM shall produce a plan view depiction of the April -May 1999 shoreline, adjusted equilibrium toe of fill and the field -verified hardbottom mapping. The latest aerial mapping effort performed by County staff will be imported into the drawings of the plan view characteristics of the beach nourishment Projects with the resource information for comparison. This map will be utilized to determine potential impacts associated with the beachfill template to the nearshore hardbottom areas. Alternative beachfill templates will be overlaid as a layer. The beach nourishment templates will be imported as the final layer to determine total acreage(s) of impact to viable nearshore hardbottom communities, Such impact acreages will be computed from this overlay information and presented to County staff for consideration. Task 4: County -Wide Beach and Offshore Profiles 4.1 BEACH AND OFFSHORE PROFILE SURVEYS Reach and offshore profile surveys will be conducted to acquire updated information in those areas of the County not currently subjected to monitoring by the Sebastian Inlet Taxing District and the PEP Reef Monitoring. Beach and hydrographic surveys will be performed from the dry upland beach (typically beginning at the FDEP Reference Monument) to an average distance of approximately 31000 ft offshore or to the —30 ft NOVD contour (whichever results in the greater profile line length). In addition to the anticipated physical limits of beachfill placement north -south within each Beach Sector, surveys in each Sector will extend 1,001) feet north and 3,000 feet south. These data will be necessary to guide the permitting and design documents to be prepared for each of the identified Beach Sectors requiring beachfill placement. To provide coverage, the following stations will be surveyed in April -May 1999. In addition, stations that are routinely surveyed by the FDEP using hydrographic survey techniques (i.e., long -line surveys) are also identified below. These data will supplement the County's long-term beach monitoring program. The beach profile lines to be surveyed are as follows: R-33 R-66 R-106 T-36through R-51, inclusive R-69 R-108 R-54 T-72 1k-109 R-57 R-75 R-110 R-60 R-93 R-111 R-63 R-99 through R-104, inclusive T-117 Further, available data has been analyzed to identify those FDEP Reference Monuments which should have bathymetric lines run further offshore to delineate portions of the Indian River Shoal. This information will be utilized to locate the jet probes for the geotechnical investigation phase of the work. Below are the FDNR Reference Monuments and recommended profile line lengths necessary to capture the horizontal extent of the Indian River Shoal feature: