4.1 Geology and Soils
placed on the receiver sites and the predicted years in Table 4.1-1 and thickness at the sandbars would
be less. Impacts would continue to be less than significant and no mitigation measures would be necessary.
Alternative 2
4.1.3
Impacts of Alternative 2a
Receiver Sites
Under this alternative, nine receiver sites would receive sand (refer to Table 2-1). At these receiver sites,
impacts would be similar for those described for Alternative 1. Table 4.1-1 shows time estimates for the
erosion of sand replenishment fills. Even though different amounts of sand are proposed for some receiver
sites under Alternative 2, the information given in the table for the receiver sites proposed under Alternative
2 is not expected to substantially differ. The increases in the offshore sand bars for the receiver sites where
more sand is proposed than under Alternative 1 (i.e., South Oceanside, South Ca rlsbad North, South
Carlsbad South, Torrey Pines, Mission Beach, and Imperial Beach) would be short-term and would not
cause significant geology and soils impacts. Accordingly, impacts would not be significant. The receiver
sites where no sand is proposed (i.e., North Carlsbad, Batiquitos, Leucadia, and Moonlight Beach) would
not benefit from wider beaches under Alternative 2. Additionally, the benefit of added shoreline protection
to fragile bluffs at the Batiquitos, Leucadia, and Moonlight Beach receiver sites would not be realized under
this alternative. Sand placement in spring would have the same benefits as described for Alternative 1.
R
Borrow Sites
Similar impacts to geology and soils would occur under this alternative. The same borrow sites would be
used under this alternative but at different quantities. The proposed dredging activities would take sand
from borrow sites outside (deeper than) the depth of closure and place sand within the three littoral cells.
New sand would be introduced to the system. As such, the borrow sites would not intercept sand that
typically moves back and forth to the beach; they would not detract from normal littoral processes which
typically rebuild beaches in the summer. No significant geology and soils impacts are anticipated to occur
to the dredge borrow sites with implementation of Alternative 2.
Regional Beach Sand Project EIR/EA
Page 4.1-9
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