Turbidity plumes may interfere with the foraging of seabirds including the California
brown pelican and double-crested cormorant. Turbidity plumes would affect temporarily
a relatively small portion of the foraging area for these species. Impacts of turbidity on
seabird foraging would be adverse but insignificant.
The beach downcoast of the Ash Avenue site is designated Critical Habitat for wintering
western snowy plovers. Beach fill activities at Ash Avenue should not have a significant
adverse impact on the Critical Habitat. Snowy plovers foraging downcoast from Ash
Avenue would not be disturbed by equipment placing sand at the Ash Avenue site.
Because littoral transport in fall and winter is primarily downcoast, the placement of
sand at the Ash Avenue site during these seasons will not cause the mouth of
Carpinteria Marsh to close. There may be a slight potential that sand placed on Ash
Avenue could move downcoast and close the mouth of Carpinteria Creek. Sand will be
monitored during beach fill operations. If it is observed to move downcoast and close
the mouth of Carpinteria Creek, BEACON will reopen the mouth with a bulldozers. With
this measure in place, significant impacts to Carpinteria Creek will be avoided.
3.3.3 Oil Piers
All of the intertidal substrate within the area proposed for beach enhancement at Oil
Piers is sand. Placement of sand on the beach at this site would have an adverse but
insignificant impact on sandy intertidal animals. Offshore of the beach enhancement
site, the substrate in the shallow subtidal also is primarily sand but scattered low rocks
are found at the western end. The movement of sand offshore may bury these rocks.
The rocks that were observed in the shallow subtidal at Oil Piers supported little marine
life indicating that they may be scoured and/or buried naturally. The impacts of sand
burial to this habitat would be adverse but insignificant.
A significant rocky intertidal area is located about 1,200 ft. west of the western end of
the Oil Piers beach placement site. Sand movement is almost never upcoast in this
area, and significant impacts to this habitat would not be expected.
Kelp occurs about 1,500 ft. off the downcoast end of the Oil Piers site. Offshore
movement of sand at this site was not analyzed but, based on the analysis done for
Goleta Beach and Ash Avenue (Moffatt & Nichol 2000) sediment deposition would be
expected to be minimal. To insure that kelp in this area is not adversely affected by the
BEACON project, the kelp bed will be monitored.
Depending on the method and rate of placement as well as the percentage of fine
sediment, the proposed project would create temporary turbidity plumes in nearshore
coastal waters. Scattered rocky habitat and kelp beds offshore of the proposed sand
placement site would be expected at times to be subjected to turbidity from BEACON's
beach enhancement project. Brief pulses of turbidity that lasted a day or two would not
be expected to have a significant adverse impact on these resources. However,
extended turbidity could have a significant adverse impact. BEACON proposes to
monitor turbidity during beach fills. If the monitoring indicates turbidity is occurring in
3208 Bio Report