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. Because sediment transport and currents are primarily downcoast
during the winter when sand replenishment would occur at Goleta Beach, turbidty
plumes from beach placement would not be expected to affect the ESH off Goleta Point.
However, turbidity plumes would probably extend to the kelp bed east of Goleta Beach
and, at times, may extend offshore to the area where eelgrass may occur. Brief pulses
of turbidty 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 the kelp bed and eelgrass area for extended
periods, the rate of placement of sand will be modified so that large, long lasting
turbidity plumes are no longer created. The turbidity criterion will be that turbidity
plumes that extend offshore as far as the eelgrass bed (approximately 1,500 ft.
offshore) or downcoast into the kelp bed (approximately 1,700 ft. downcoast) should not
last for a period of more than 6 days. Because of this monitoring and response
program, turbidity created by beach fill will not have a significant effect on biological
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.
Grunion run regularly at Goleta Beach. Because beach enhancement at Goleta Beach
will not occur during the grunion spawning season, no impacts to grunion spawning will
occur for the proposed project.
Sediment placed on Goleta Beach has the potential to move down coast and close the
mouth of Goleta Slough. The project will monitor the movement of sediment during and
after the placement of sand on Goleta Beach. If monitoring indicates that the slough
mouth is closed as a result of beach fill activities, BEACON would reopen the slough
mouth with bulldozers.
3.3.2 Ash Avenue
Moffatt & Nichol predicted the sand cover in the vicinity of the Ash Avenue beach
placement site based on the proposed beach fill design and the maximum proposed
volume of 100,000 cubic yards (Moffatt & Nichol 2000). From the back beach to
approximately 400 ft. seaward (+10 to -4 ft. MLLW), the predicted sand cover was
between 1 and 2 ft. thick. The habitat in this area is almost entirely sand beach with
some exposed cobble at the eastern end. Cobble underlies this stretch of beach. The
impacts of burial in these areas would be adverse but insignificant. From 400 to 800 ft.
offshore (-4 to -17 ft. MLLW), the depth of cover would be 1 foot or less. Some
scattered rocks that occur offshore the western end of the proposed beach fill may be
temporarily buried. Because the number of rocks that would be affected is few and
because natural littoral processes would uncover them within several months, the
3208 Bio Report