3.5 Cultural Resources
previously collected as part of the South Bay Tunnel Outfall Project, and the interpretation of these data
were made available (Pettus 1995).
Geoarchaeological Results
An offshore archaeological artifact site is recorded near SS-1, along the northern margin of the Tijuana
River channel, at intertidal depths (Table 3.5-1, Site 21). No survey has been recorded in the area, but
at least one stone mortar has been recovered from this site. A bathymetric high exists offshore of the
present day slough mouth. Several recorded prehistoric sites are located along the Pleistocene terrace
which defines the southern margin of the Tijuana River estuary.
The dredge area for SS-1 spans the offshore paleochannel of the Tijuana River, where the paleochannel
makes a bend from an east-west direction toward a more southerly direction. None of the vibracores
reached bedrock; all have abundant sand, and some have a shallow buried clay layer. The deepest levels
within the cores suggest fluvial sediments with poorly sorted and sandy sediments. The aforementioned clay
layer represent a transition to the presence of finer grained marsh sediments above the fluvial layer. Cores
throughout the site reveal a sequence of sedimentary environments from top to bottom as follows: offshore,
lagoonal, marsh, and fluvial. A geological cross-section based on these data reveals a gently south-dipping
contact between fluvial sediments on the bottom, and marsh above. The upper two sedimentary layers are
flat-lying lagoonal and offshore facies.
The potential for occurrence and preservation of archaeological sites within the dredge area for SS-1 is
high, given the presence of a paleochannel, and a low energy interface between fluvial and marsh deposits.
The most likely region to encounter buried cultural materials may be in the northern portion of the grid,
along the margins of the paleochannel.
Historic Results
No seismic or magnetometry data were acquired at this location. However, other remote sensing surveys
have been conducted in the area (Pettus 1995). Results from these offshore surveys were reviewed for
this project. A recorded historic site (the destroyer USS Hogan (DD178)) is located offshore of the
project area. A military aircraft (S2F Tracker) and a sunken sailboat were recorded in 97 feet of water
during studies related to the South Bay Tunnel Outfall (Pettus 1995). The project area lies within a high
potential zone for historic (and modern) shipwrecks and aircraft losses.
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