4.5 Cultural Resources
D.
Has yielded, or may be likely to yield, information important in prehistory or history.
4.5.2 Alternative 1
Impacts of Alternative 1a
Evaluations of potential impacts to cultural resources within proposed borrow sites can be considered in
terms of (1) prehistoric resources, where previously exposed river valleys were available for human
habitation and remaining artifacts would be contained in now buried materials; and (2) historic resources,
where shipwrecks and other more modern human artifacts may be located. Table 4.5-1 identifies the
probability for prehistoric resources to be located within a dredge area as well as the targets in the side-
scan sonar which suggests the need for further investigation of potential historic resources. Side-scan
targets can be difficult to interpret and noted targets may, in fact, be non-sensitive resources such as
scattered gravel or a bed of sand dollars. Methods to determine with certainty include field verification by
diver or remotely operated vehicle (ROV).
Table 4.5-1
Summary of Cultural Resource Investigation Results at Borrow Sites
Potential for Occurrence
Potential for Occurrence of Historic Resources
of Prehistoric Materials in Dredge Area(1)
in Dredge Area(2)
Borrow Site
SO-9
High, but maximum potential below nine
12 identified targets; all likely remains of scattered
R
feet.
rock reef experiment, no-side scan sonar data for
R
approximately 10 percent of dredge area
SO-7
Moderate
None
None(3)
SO-6
High
SO-5
Moderate to High
None
MB-1
Moderate to High, maximum potential
3 identified targets
below 12 feet
SS-1
High
No side scan sonar available
(1)
Based on dredge area location relative to historic river channel.
(2)
Based on interpretation of side-scan sonar data.
(3)
Identified target, likely shipwreck, offshore from western boundary, 250 foot buffer must be maintained during
dredge
Page 4.5-2
Regional Beach Sand Project EIR/EA
99-69\SANDAG EIREA 4.1 to 4.13.wpd 7/17/00
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