4.4 Biological Resources
SO-5. There are two pipeline routes proposed for this site to replenish three receiver beaches. For the
Solana Beach site, the pipeline would run about 7,500 feet and go from the northeastern corner running
northeast between the Solana Beach kelp beds and then turn east to the beach near Plaza Street. Sensitive
resources in this area include kelp beds and kelp habitat and in the nearshore area there are reefs and
surfgrass (Table 3.4-6). Even though these resources are mapped, the final location of the pipeline and
anchor placements would need to avoid kelp beds, vegetated reefs, and surfgrass resources. Near the
shoreline, where the submerged portion of the pipeline would be placed, there are low lying reefs and some
surfgrass. The pipeline has been routed to go between the mapped kelp beds and avoid vegetated reefs
and surfgrass areas. Vessel traffic would have to use corridors between the kelp bed and would not be
allowed to transit through the kelp bed.
If a hopper dredge were used, the mono buoy would be located in water depths between 30 and 40 feet,
which lies between 1,875 and 2,625 feet from the shoreline, respectively. The location of the mono buoy
would have to be inshore of the kelp bed and all anchoring activities, both for the hopper dredge and for
the installation of the mono buoy, would have to avoid kelp, kelp habitat, and reefs. The recovery of the
kelp beds from the recent El Nio has been rapid and aided by the colder than normal winter water
temperature. It is possible that the kelp beds may be too extensive to allow hopper dredge use at this site.
Final decision for selection of dredge type for this site may need to be postponed until the start of the
dredging when a kelp bed reconnaissance would be recommended. No significant impacts are expected
for the emplacement of temporary pipelines and mono buoy at this location.
The second pipeline for this site would run from the southeast corner of the dredge area and run about
4,000 feet and go directly onshore to a location at about 18th Street in Del Mar. Sensitive resources near
this pipeline route include possible kelp, low lying mud reefs to the south, and possible surfgrass to the north
near the shoreline (Table 3.4-6). The pipeline location has been selected to avoid these resources and all
anchoring activities would have to avoid these resources. If the kelp bed inshore of the borrow site is
present then the pipeline route would need to be altered to avoid kelp beds. Vessel traffic would have to
avoid transits through the kelp and anchoring of the dredge would have to avoid placing anchors in the kelp
beds.
If a hopper dredge were to be used, then the location of the mono buoy would be in water depths of
between 30 and 40 feet located between 1,875 and 2,625 feet from the shoreline, respectively. This
location would be south of the potential surfgrass area and north of the reefs and all anchoring activities
associated with mooring the hopper dredge and installing the mono buoy would have to avoid these reefs
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