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Unformatted text preview: e town of Fort Dauphin is
located). The shoreline within the bay consists of wide, sandy beaches backed
by large sand dunes. The beaches become relatively narrow as one approaches
the project site, with scattered rock outcrops along the shoreline at the site. The
Ehoala headland (and adjacent shallow rock shelf and small islands) is a
dominant feature at the project site, extending towards the NE off the Cape.
Extensive site investigations were undertaken in 2003-04, including
topographic, beach and hydrographic surveys, and geophysical investigations.
Unfortunately, it was not possible to collect geotechnical information (i.e.
boreholes), as the mobilization cost to get a jackup barge to the site was in
excess of US$1 million. The geophysical information was verified to the extent
possible using diver inspections, underwater test pits and land-based cores.
However, the subsurface conditions represented a key uncertainty during the
design process, particularly for the quay structure and dredging.
Figure 3 illustrates the bathymetry within Fausse Baie des Galions. Key
features of interest include the shallow shelf feature adjacent to the Ehoala
headland, as well as a series of shoals (reef outcrops) scattered around the bay
and beyond. Interpretation of the geophysical data indicated a complex, layered
geology at the port site. The shallow shelf feature was determined to be a
combination of aeolianite and beach rock overlying sand with cemented layers,
while the adjacent area (to the north) was determined to be loose sediments. Figure 3. Bathymetry within Fausse Baie des Galions 4 PORT LAYOUT The bathymetry and subsurface conditions were important considerations in
the development of the port layout. In particular, the Ehoala headland and
adjacent rock shelf and small islands provide a certain level of natural shelter to
the south end of the bay from the persistent southerly swell waves. Given the
shallow depths in this area, this was a natural starting point for the breakwater.
In addition, the aeolianite/beach rock feature was considered to provide a good
foundation for the quay structure, while the adjacent area of loose sedim...
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- Spring '14