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rrclmlie dAppraaell Pages a Task 1.9 Prepare Geotechnical A Geotechnical and Sand Source Investigation Report will be generated which will detail the field, interpretive and laboratory procedures utilized to acquire and analyze the geophysical data, geophysical and geotechnical data, core logs, GSD for each test sample (assuming four samples per core) and preparation of maps. The above • interpretive: maps will accompany graphics of the areas investigated from the side scan grid and bathymetric surveys for candidate borrow areastsources containing suitable sands for beach placement. The side scan data will he generated as a plan view interpretive AutoCAD format rendering of the relative location of surficial sediment type, hardbottom features, and other visible features from the side scan records. For costing purposes, it is assumed that side scans and bathyrnetric surveys will reap a total area of 1,250 acres. Hardbottorn areas identified by the side scan sonar images for locations within and contiguous to tine areas surrounding the borrow areas will be investigated if these areas are anticipated to impact on the design of the borrow area. It is further assumed that magnetometer surveys, if required by FDEP, will be performed under a supplemental work order from the County during the permitting process. Sub -bottom Survey (Supplemental Work asRe-guired) If sub -bottom data records are deemed necessary and performed to confirm the depths to rock, the vibracores will provide the geophysical data necessary to map the sub -bottom strata and sand/material layers. If rock is encountered within the candidate borrow areas of the surrounding areas during the jet probe investigation, the acoustic records will utilize the core(s) c'ata for "ground -truth" verification of the material thickness. The cost of performing the seismic surveys concurrent to the side -scan surveys of the borrow areas will not exceed $10,000. This work will include preparation of contour maps of the thickness of sandy sediments and the elevation, referenced to NGVl7, of the underlying bedrock will be prepared. ATM will provide a preliminary ranking of sand source areas based on the sediment characteristics associated with each candidate borrow area. A high-resolution, three-dimensional color contour map will be produced, as will mesh plots of sand thickness and depth to bedrock. Task 2; Environmental Assessment of Nearshore Hardbottom Resources Introduction The proposed Project initiatives for BPP Planning Sectors 1, 2, 3 and 7 comprise the restoration of approximately 5.5 miles of Iridian River County Atlantic Ocean shoreline. It is along these segments of shoreline where the hardbottom resource environmental assessment (EA) will be concentrated. Verification -level work will be performed in Sector 5, (as indicated in Task 2.7), since an extensive hardbottorn mapping and characterization effort was conducted in this area in 1993. Task 2,1 Review of Published Information and Determine Field Inyestigation Boundaries As indicated in Task 1.1, previously prepared documents concerning nearshore biological resources, aerial photographs, and Prefabricated Erosion Prevention Reef Project monitoring efforts have resulted in the accumulation of information which will be reviewed prior to conducting any field work in association will'i this Project. County files will be accessed, and inquiries will be directed to the appropriate state and federal agencies (e.g„ FDEP, USACE, U.S. Fish and Wildlife Service) to determine that all available information on nearshore resources in the Project areas is properly reviewed. Task 2.2 Video Transects to Perform t- iardbottomfReef Ma in Natural resource mapping and hardbottom area characterization along the nearshore area (to approximately -18 feet NGVD) contiguous to each sand placement area and nearshore zone fronting the adjacent beaches that extend 1,OOD feet north and 3,000 feet south of Project beach nourishment areas will be performed. This work will be conducted between May 1 to June 30 or as soon as favorable weather and water clarity conditions permit. ATM shall acquire all nearshore resource information within these boundaries and pertaining to the proposed Project borrow area and fill area. YP4PMW6 W9404 V4WI $;NWF 14 l4[iNK 1WN—,