3.1 Geology and Soils
South Carlsbad (North and South)
The South Carlsbad receiver sites are located on a low tide terrace, which lies in front of coastal cliffs
between Agua Hedionda and Batiquitos Lagoon. The steep coastal cliffs in this area have been continually
forming from wave action cutting against the marine terrace. This process has occurred since the last
relative still-stand of sea level, approximately 6,000 years ago (FRH 1997). The existing receiver site
comprises the flat, rocky, shallow part of the shoreline and is part of the critical erosion area defined by
CCSTWS.
Batiquitos
The Batiquitos receiver site is located on a low terrace, which lies in front of coastal cliffs south of
Batiquitos Lagoon. The steep coastal cliffs in this area have been continually forming due to wave action
cutting against the marine terrace. The existing receiver site comprises the flat, mixed sand and rock
shallow part of the shoreline visible during periods of low tide.
Batiquitos Lagoon was formed in the geologic past when the sea level was at a lower level, the shoreline
was located farther to the west, and existing streams quickly eroded the exposed marine terraces. This led
to the formation of steep canyons and as the sea level rose (approximately 18,000 years ago), sediments
quickly filled the lower reaches of the channels that created the lagoon. Batiquitos Lagoon is currently a
tidal lagoon due to an enhancement project completed in early 1997 that opened the inlet channel to tidal
flows.
The Batiquitos receiver site is located within the Oceanside Littoral Cell and is subject to similar transport
processes as those described for the South Oceanside receiver site. The receiver site is located within a
critical erosional area (USACOE 1991).
Leucadia
Similar to the Batiquitos receiver site, the Leucadia receiver site is located on a low terrace, which lies in
front of coastal cliffs that characterize Leucadia's beaches. The steep coastal cliffs in this area have been
continually forming due to wave action cutting against the marine terrace. The existing receiver site
comprises the flat, rocky, shallow part of the shoreline visible during periods of low tide.
Page 3.1-6
Regional Beach Sand Project EIR/EA
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