Bathymetric Survey
Vibracore Sampling
Field Images

Bathymetric Survey

Coastal Planning & Engineering, Inc. (CPE) conducted a bathymetric survey in support of the Post-Storm Lido Key Beach Repair Project. On 3 November 2005, CPE hydrographic surveyors arrived in Sarasota County to conduct the survey. The team began the survey by setting a water level meter to collect tide data throughout the survey. Over a two-day survey, 37 lines miles of bathymetric data were collected on the ebb-tidal shoal offshore New Pass.

After post processing the data, a color ramped surface was created and plotted in a GIS for further analysis. Historical datasets were added to the GIS to determine target areas for the following phases of the investigation .

On 17-18 December 2005, Coastal Planning & Engineering (CPE) geologists conducted a geophysical survey on the ebb-tidal shoal at New Pass near Lido Key, Florida. CPE utilized the Edgetech 512i sub-bottom profiler, the Edgetech DF1000 sidescan sonar, and the Geometrics 882 marine cesium magnetometer, all deployed from the USGS/Eckerd College research vessel G.K. Gilbert. This survey resulted in the collection of 32.5 line-miles of seismic reflection, sidescan sonar, and magnetometer data.

Initial seismic data interpretations indicate the existence of two potential sand source areas. The primary target is the New Pass ebb-tidal shoal, where seismic data show the possible presence of beach-compatible sands. A secondary sand target occurs in the northwest section of the study area, where a bowl-shaped sediment deposit is present. The seismic data indicate that sands in this deposit may be of mixed quality and require further information to determine beach compatibility.

Both the sidescan sonar and magnetometer data resulted in several minor targets worth further exploration. These targets will be revisited during the cultural resources investigation in the near future.

CPE geologist are currently reducing and interpreting the data from this survey. These data results will serve as the basis for choosing vibracore locations that will help describe the best possible source of beach-compatible sands near New Pass. Vibracore operations are scheduled to begin the first week of January 2006 and are expected to take several days to complete, depending on weather conditions.

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Vibracore Sampling

On 4, 5, and 9 January 2006, CPE geologists and subcontractors began collecting sediment vibracores on the ebb-tidal shoal at New Pass near Lido Key, Florida. CPE utilized a Rosfelder model P3 Electric vibrating bottom corer outfitted with a 20 foot aluminum barrel, deployed from the USGS/Eckerd College research vessel G.K. Gilbert. Over these three days, CPE successfully collected 15 undisturbed sediment cores from within the prospective borrow area.

After collection, the cores were cut in to five-foot sections and transported to Eckerd College where a second CPE geologist field crew set-up a field laboratory for core processing. The cores were split, physically described and sampled. After sampling, the cores were photographed and sealed for transport to CPE’s storage facility in Boca Raton. The samples were also transported back to CPE’s Boca Raton headquarters where they are currently undergoing detailed sediment analysis.
CPE is currently completing the sediment analyses, plotting the new vibracore data onto the collected seismic data, and finalizing the borrow area design as well as the final report.

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