4.2 Coastal Wetlands
Impacts of Alternative 1a
San Luis Rey River
No impacts to the San Luis Rey River are anticipated from the project. Sedimentation from the South
Oceanside beach fill would not be expected to reach the river, which is located over one mile to the north.
Similarly, turbidity plumes would not be expected to travel that far north of the site.
Loma Alta Creek
The Loma Alta Creek is a seasonal freshwater creek that discharges into the ocean near the south end of
the proposed South Oceanside receiver site. The City of Oceanside constructs a sand berm in front of the
creek to prevent flow between Memorial Day and Labor Day, and during the wet season excavates a
temporarychannelto facilitate stream flows to the ocean for flood control. Short-term (less than five years)
beach widening on the order of 50 to 100 feet is predicted in the vicinity of the creek (Appendix C). This
may require the winter discharge channel to be lengthened, but because the City currently maintains the
creek outlet on an as-needed basis, no significant impact to the creek habitat would occur. Turbidity
generated from receiver site construction would not be expected to impact the water quality of the creek.
Buena Vista Lagoon
Buena Vista Lagoon is closed to tidal influence by a man-made weir. The City of Oceanside maintains a
discharge outlet to the ocean for flood control. For similar reasons as Loma Alta Creek, no significant
impacts to water or habitat quality would occur.
Agua Hedionda Lagoon
The ocean inlet to Agua Hedionda Lagoon is located over 0.5 mile south of the proposed North Carlsbad
receiver site and over one mile north of the proposed South Carlsbad North receiver site. Turbidity plumes
from receiver site construction are anticipated to be localized, less than 100 to 1,400 feet downcurrent,
under typical current speeds, and would not extend very far into the lagoon even under maximum current
speeds. If project-related turbidity did enter the lagoon, particulate concentrations would be low given the
distance to the lagoon and rapid settling rate of the predominantly sandy material. There would be no
significant impacts to the lagoon due to turbidity.
Page 4.2-2
Regional Beach Sand Project EIR/EA
99-69\SANDAG EIREA 4.1 to 4.13.wpd 7/17/00
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