Fort The Town of Hillsboro Beach recently completed a truck haul beach nourishment “project of opportunity” to mitigate an erosional hot spot. Increased construction costs and a lack of economically available beach compatible sand sources have resulted in counties and municipalities developing creative solutions to restore critically eroded shoreline. The Town is located on a barrier island and enforces an ordinance requiring that all excavated sand from building foundation construction remain within the Town limits. In 2007, a source of beach compatible sand from within the Town was identified. The beach compatible material resulted from a local construction project which involved excavating a boat basin adjacent to the Intracoastal Waterway and foundation excavation on a separate lot east of A1A. Excavated sand from both of these sources was stockpiled together on a vacant lot in the Town, approximately ½ mile south of the beach placement site. After receiving all necessary permits during the early stages of the marine turtle nesting season in June 2008, the Town constructed the Project using the locally available sand.

The Town is located in the northern portion of Broward County and borders the City of Deerfield Beach to the north and Hillsboro Inlet to the south. The erosional hot spot is located in the northern portion of the Town, immediately downdrift of a groin field in Deerfield Beach. Permit applications for the project proposed the use of two upland sources of beach compatible sand; the Ortona Sand Mine in LaBelle, Florida and the locally excavated sand. This approach provided the Town with the flexibility they needed to plan and implement the project. Close coordination was required to sufficiently manage the design, permitting, and construction schedules for this Project.

Permit applications for the Project were submitted on August 27, 2007 and processed through the Corps of Engineers (COE), Florida Department of Environmental Protection (DEP) and Broward County Environmental Protection and Growth Management Department (EPGMD). The project proposed placement of approximately 14,000 cubic yards of fill material along 430 feet of beach. Although the Project was small in scope and only impacted sandy dry beach and intertidal and subtidal areas with small areas of relict beach groins exposed by erosion, a number of issues were raised during the permitting process. These issues included potential direct and indirect impacts to the recently listed species of coral Acropora cervicornis and A. palmata, potential impacts to foraging areas for marine turtles, potential impacts to nesting marine turtles, and the compatibility of the proposed local source of sand. A Biological Opinion was required from the U.S. Fish & Wildlife Service due to the potential impacts to nesting marine turtles.

The Town is also conducting a demonstration project utilizing an innovative technology to address shoreline erosion on the northern one mile of the Town’s shoreline. The Town placed Pressure Equalizing Modules (PEM’s) in the beach down to the mean low waterline. The PEM’s were placed in the beach in late February 2008. A total of 33 rows of PEM’s were placed within the 1 mile of shoreline downdrift of the groin field. Two rows of PEM’s were placed within the eroded beach at the site of the truck haul project (430 feet). The permitting agencies agreed that the 14,000 cubic yards of material proposed to be placed within the truck haul project area would not have a substantial impact on the monitoring of the PEM’s, but would be incorporated into the experimental test plan accounting for the volume of fill material. The Town is monitoring the effectiveness of the PEM’s over a three year experimental test period. From January through May 2008, Coastal Systems International, Inc and the Town worked with the permitting agencies, resulting in the commencement of project construction in early June. Based on an in-water survey, no colonies of the listed coral species were observed and the agencies ultimately agreed that the proposed Project would not result in any direct or indirect impacts to the hardbottom resources located approximately 450 feet offshore.

Since loggerhead and green turtle nesting season becomes active in June, both the Florida Fish and Wildlife Conservation Commission and the U.S. Fish and Wildlife Service required construction activities to cease on June 15, with several restrictions to protect nesting marine turtles. As a result of the permit process, special conditions requiring daily surveying for new marine turtle nests and the relocation of any nests identified by the surveys were included in the issued permits. In anticipation of permit issuance, the Town bid the project and committed to entering into a contract with Eastman Aggregates Enterprises, LLC immediately upon issuance of all permits.

The DEP permit was issued on May 28, 2008 and the COE permit was issued on June 2, 2008 and Eastman quickly mobilized and began construction on June 5, 2008. An upland hopper was utilized to accept truckloads of sand and a conveyor system delivered the sand to the beach through a narrow access corridor, limited to approximately 20 feet wide by 200 feet long. Since all work, including grading of the placed material and removing machinery from the beach, had to be completed by June 15 and since work could not continue at night, only 9,000 cubic yards of material was placed. The 9,000 cubic yards of sand was obtained locally, with no material brought in from the Ortona mine. The material was screened to ensure the highest-quality sand was placed on the beach. Use of the local source of sand resulted in a cost savings of approximately $33.80 per cubic yard, or $304,200.00. The unit costs of the project are provided in Table 1; total project costs were $339,840.

The local source of sand was determined by the DEP to be beach compatible based on the results of the geotechnical evaluation. The local material was also acceptable for marine turtle nesting, as one nest was observed in the beach in early July. By the end of marine turtle nesting season, a total of three nests were observed in the new material.

The project was completed in 10 days with approximately 9,000 cubic yards of material. Although the volume of sand is small in comparison to large nourishment projects, the Town was able to complete an economical project utilizing excavated local material to provide improved storm protection for upland property and infrastructure. The use of this locally available sand resulted in significant cost savings to the Town, as compared to the cost of using known beach compatible sand from a distant sand mine. DEP project managers and geologists visited the site on June 17, 2008 to observe the sand quality and the sand sorting operation. This project provided an interim measure addressing erosion in a hot spot south of the Deerfield Beach groin field. On July 3, 2008, the Town applied for a more comprehensive beach nourishment project that will extend from approximately 1,300 feet north of the Town’s boundary and a total of 7,150 feet.

By Paden E. Woodruff, DEP, Bureau of Beaches and Coastal Systems; and John F. Studt, Coastal Systems International, Inc.

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