4.4 Biological Resources
the area would be expected to be within the range that these resources would naturally experience. Indirect
turbidity impacts would be less than significant.
Dredge Equipment Impacts
The placement of temporary pipelines, the deployment of anchors for moving the cutterhead dredge,
installation of the mono buoy for the hopper dredge, and vessel movements have the potential to affect
sensitive resources. To avoid significant impacts to sensitive resources (i.e., reef habitat with well
developed biota, kelp and kelp habitat, artificial reefs, and surfgrass) pipeline routes and vessel traffic need
to utilize corridors free from these resources. Similarly, anchor and anchor cables used to position the
dredge and to hold pipelines inplace must avoid hard bottom habitats, kelp beds, and surfgrass. This is also
good operational practice, as anchors do not hold well on hard bottom. The relationship between
proposed sensitive resources and features at each borrow site is provided below.
SO-9. The proposed pipeline route for this borrow site extends about 10,500 feet south from the borrow
site about 3,000 feet south of the Oceanside Harbor and San Luis Rey River mouth where the pipeline
would then turn to the east and extend about 7,500 feet to the beach. If a hopper dredge is used, the mono
buoy would be located in water depths between 30 to 40 feet located between 2,600 and 4,500 feet,
respectively from the shore. There are no sensitive resources near the proposed pipeline pathway (Table
3.4-6). Commercial fishermen have indicated that there may be an isolated patch reef/scattered rock near
the pipeline route at about the 25-foot depth contour. If this reef exists at the indicated location, then
anchoring and emplacement of the mono buoy would need to avoid this reef with a 300-foot buffer zone.
No significant impacts are expected from the emplacement of temporary pipelines and mono buoy at this
location.
SO-7. There are two pipeline routes proposed for this site to replenish several receiver beaches. For the
South Carlsbad North site, the pipeline would run about 3,000 feet and go directly from the eastern area
of the borrow site to the beach just upcoast from the Batiquitos Lagoon. Sensitive resources in this area
includes a series of artificial reefs located along the eastern edge and inshore of the borrow site (Table 3.4-
6 and Figure 2-16). The locations of these reefs are known and all anchoring activities would have to avoid
these reefs. Near the shoreline where the submerged portion of the pipeline would be placed there are low
lying reefs and some potential surfgrass as identified by commercial fishermen. The pipeline has been
routed so as to go between the low lying reefs and be just south of the potential surfgrass area. If a hopper
dredge were used, the mono buoy would be located in water depths between 30 and 40 feet, which lies
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