4.2 Coastal Wetlands
first year. As described under Alternative 1, maintenance dredging has historically ranged from about
100,000 to 465,000 cy per year. The volume of sediment possibly entering the lagoon from the project
would not increase the number of times it would be dredged, but may increase the total amount to be
dredged. As described under Alternative 1, SANDAG has committed to a lagoon monitoring program
to determine the amount of sedimentation above natural conditions. Any project-related accumulated
sediment would be removed. Dredging of accumulated sediment, if necessary, would not result in any
significant impacts to lagoon habitat.
Batiquitos Lagoon
Under this alternative, three sites in Encinitas would not receive sand, but sites to the north of the lagoon
would receive more sand than under Alternative 1. It is estimated that possible sediment accumulation from
the project would be on the same order of magnitude as Alternative 1 (27,000 cy over five years), but
likely less. The model predicts well over one half of that volume in the first year after replenishment. As
with Agua Hedionda lagoon, the volume of sediment possibly entering the lagoon from the project may
increase the total amount to be dredged. As described under Alternative 1, SANDAG has committed to
a lagoonmonitoring programbased on the Navy's on-going effort to determine the amount of sedimentation
above natural conditions. Any project-related accumulated sediment would be removed. Dredging of
accumulated sediment, if necessary, would not result in any significant impacts to lagoon habitat.
San Elijo Lagoon/San Dieguito Lagoon/Los Peasquitos Lagoon
The volume of sand at receiver sites Cardiff, Solana Beach, and Del Mar would be the same as under
Alternative 1, but would be slightly greater for the Torrey Pines site. The predicted impacts to these three
lagoons would be similar under this alternative; specifically, up to one more inlet opening over the course
of a year during the monitoring period (maximum 5,000 cy). The monitoring program described in Section
2.5 and above would be suitable to verify no significant impacts.
Mission Bay/Tijuana Estuary
Under this alternative, both receiver sites would receive 50 percent more material than under Alternative
1. However, in both cases the increased sediment would not affect significantly coastal bodies. In the case
of Mission Bay, any substantial sediment movement to the south would be prevented from the reaching the
entrance to the bay by a jetty. In Imperial Beach, the northward current would prevent sediment from
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