2.0 Alternatives Considered
For both dredge vessels, the floating portion of the dredge discharge line would be marked and lighted for
navigation safety and a Notice to Mariners would be issued through the U.S. Coast Guard. The discharge
line would be trucked or floated in segments to the appropriate placement locations and assembled using
cranes and other equipment. The line may be a combination of plastic (HDPE) and steel materials
depending on need and availability, and would be approximately 30 inches in diameter.
Booster pumps would be used approximately every 10,000 feet on longer reaches. One offshore booster
pump may be necessary for the offshore length from SO-9 to the Oceanside receiver site; however, it is
possible that the dredge itself could move the material the entire distance to shore. Booster pumps would
be necessary where onshore pipelines would convey material to the receivers site(s) and the total onshore
distance would be approximately 10,000 feet. An onshore booster pump would be necessary along the
length from the Oceanside to North Carlsbad receiver sites. Onshore booster pumps would also be
necessary to convey material to South Carlsbad North, Moonlight Beach, and Torrey Pines. The exact
locations of pumps are not known at this time.
For all pipeline delivery routes, the floating and submerged portions of the dredge discharge line would be
routed to avoid sensitive resources to the maximum extent feasible. For instance, the discharge line would
extend westward beyond kelp beds to prevent dredge vessels from traversing kelp beds. The contractor
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would also be conditioned to avoid traversing the CDFG artificial reefs near SO-9 (Figure 2-15), SO-7
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(Figure 2-16) and MB-1 (Figure 2-19). That means no hopper dredge (empty or full) or discharge lines
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may traverse these three artificial reef locations. As shown in Figure 2-16, the possible northern dredge
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discharge pipeline path at SO-7 would be floating above CDFG artificial reefs 9 and 1. This floating pipe
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would not affect the submerged reefs, but it has been sited to make landfall in the nearshore locationwithout
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reefs or surfgrass. The contractor would also be conditioned to avoid any discharge pipe placement within
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the Tijuana Slough National Wildlife Refuge, that means any discharge pipe would make landfall north of
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the terminus of Seacoast Boulevard in Imperial Beach.
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Discharge Line Management and Maintenance
Assuming use of a cutterhead suction dredge, the discharge line would require ma nagement and
maintenance activities during the construction period. After replenishment was complete, all pipelines
would be removed. The line would be placed along the back of the beach (i.e., eastward) to minimize its
exposure to wave forces. At locations with no existing shore protection or bluffs, the discharge line would
lie along the highest landward portion of the existing beach or cobble berm. These locations include North
Oceanside, Buccaneer Beach, Buena Vista Lagoon, South Carlsbad, Batiquitos, Leucadia, Moonlight
Regional Beach Sand Project EIR/EA
Page 2-41
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