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Am 108 hut -,W I An eight (8) -year renourishment interval is sought for project cost effectiveness, maximum funding participation by the Florida Department of Environmental Protection (for those projects which are eligible for state support), and realistic sand placement volumes as advance nourishment. A fifteen -year design level storm (6.67 percent probability of recurrence in any given year) was determined to provide the optimum project volumetric requirements. It is assumed that sand requirements for each identified shoreline sector targeted for restoration is available and of suitable quality so as to minimize the overfill requirements. That is, the sand must be compatible, 'or nearly so, with the existing or 'native' sand on the pre -project shoreline. Final sand volume requirements for each shoreline designated for restoration will be determined by many design factors, among which sand compatibility will be critical. The total sand vplume recommended to initially restore the shoreline sectors envisioned to receive sand is approximately 1.89 million cubic yards. The borrow area(s) for this sand will be identified by Indian River County in a study to be initiated in December 1998, with field work to commence in Spring 1999. Once borrow area(s) locations relative to sectors planned for sand placement are determined, the critical design factors including pumping distances, sand quality and quantity, and nearshore hardbottom characterizations will allow project estimates to be refined. The beachfill projects are assumed to require approximately 1.95 million cubic yards of sand placed along a total of approximately 41,000 feet (7.8 miles) of the Indian River County Atlantic Ocean shoreline. Exact construction berm elevations and widths will be dependent upon sand quality and shoreline conditions at the time of preliminary design. Unit beachfill volumes at this juncture appear to range between approximately 40 to 53 cubic yards per front foot of shoreline. The above values were determined following analysis of existing conditions and modification of project boundaries (and the requisite beachfill volumes) from those sectors identified in the BPP. In contrast to the beachfill parameters cited above (as presented in the BPP Update), the total estimated shoreline length requiring beachfill was 36,000 feet (6.8 miles), with 1.51 million cubic yards placed in unit sectors varying from ten (10) to 80 cubic yards of sand per front foot. Uniformed sand unit prices are assumed for the purpose of plan development and costing purposes for each "project sector" at $8 per cubic yard in place. These unit costs were derived by Indian River County and were reduced to $7 per cubic yard for the anticipated projects in Sectors 1, 2 and 3 to account for a probable single mobilization of dredging and beachfill equipment to construct all three (3) sector improvements sequentially. Essentially the mobilization fee is assumed to be approximately $1,000,000 and thus the unit sand placement is estimated at $6 per cubic yard. Mobilization of dredging equipment and work crews will be dependent upon sand source proximity to each of the sector beachfill sites, the dredge plant type necessary to properly access and excavate sand from the borrow area(s) and transport it to shore, the proximity of such equipment and crews to the project site at the time of project bidding, and whether one or more projects are anticipated to be bid sequentially. JANUARY J•9, 1999 -58- • 0