BOEM in October 2022 issued its final Environmental Assessment for the Commercial Wind Leases in the Morro Bay Wind Energy Area under the National Environmental Policy Act. This document allows the wind area leaseholders to conduct site assessment and site characterization activities. The site characterization includes surveys of the seabed floor to locate sites for mooring systems and cables and to avoid Shallowater hazards. This document does not cover construction of any wind energy facility.
A copy of this document is available at https://www.boem.gov/renewable-energy/state-activities/morro-bay-final-environmental-assessment-and-appendices
Based on this document, there was a finding of no significant impact. When BOEM made this conclusion it did so on the basis of “assumptions about, and expected scenarios of, reasonably foreseeable site characterization and site assessment activities based on regulations, relevant experiences on the Pacific OCS [Outer Continental Shelf], and SAP’s [Site Assessment Plans] submitted to BOEM.” These assumptions include the siting of three metocean [an abbreviation for meteorology and physical oceanography] buoy installations with a maximum of 21-30 vessel trips over a 5 year period for installation/maintenance/and decommissioning, performance of high-resolution geophysical surveys without air or water compression devices that might generate acoustic pulses, installation of metocean buoy installations in one day, decommissioning of the buoy in year 6 or 7 of the lease, and a staging site in the Port of Morro bay for the site assessment activities with a range of 464 to 873 round trips for project-related vessels. The project also assumed that noise would be generated by HRG survey equipment, coring and sediment sample collection, vessel engines participating in site characterization surveys and metocean buoy work, and diesel engines on any metocean buoys that would not be operated by solar or wind.
Metocean buoys reviewed range from 10 meters to 12 meters across (33-40 feet). The Final Environmental assessment concluded that any risk of a spill due to a collision between vessels or a vessel running into a buoy would be small and limited in duration. Equipment associated with the site survey could be lost at sea which could cause damage to the seabed floor during a recovery action or may need additional emergency response plans specific to the lost equipment. Air emissions associated with vessels, vessel auxiliary engines, and buoys used for site characterization surveys and site assessment are expected to be negligible or minor (3,022 annual metric tons per year of carbon dioxide equivalent).
Taking cores and bottom samples may impact up to 10 square meters (108 square feet) per sample but the suspension of seafloor sediment is not expected to have lasting impacts on sediment quality. The anchoring and installation of buoys would impact 2.3 square meters (25 square feet) of the seafloor but would have only temporary effects.
Marine mammals could be impacted by collisions with project-related vessels. Vessels are expected to travel no more than 10 knots per hour within the proposed action areas and have on-board Protected Species Observers (or a trained crew member). Vessel captains are expected to steer a course at 10 knots or less per hour away from any whale detected within 500 meters of the forward path of a vessel and stop the vessel to avoid striking a species. If a sea otter or sea turtle is sighted in the vessel’s forward path, a vessel is expected to slow to 4 knots per hour and steer away. Any strike by a vessel affiliated with a protected species must be reported to the Bureau of Safety and Environmental Enforcement. As of 2022, no vessel strikes of protected species had occurred in the Atlantic Ocean where similar practices are in effect since 2012.
The lease holders are expected to incorporate best management plans that include vessel strike avoidance efforts, visual monitoring, shutdowns, and reporting. Marine mammals are not expected to be injured by high-resolution geographical surveys because the models of maximum disturbance distances for mobile survey equipment being pulled at 4.5 knots would be intermittent and short in duration. Survey crews are required to have qualified Protected Species Observers monitor a 1000 meter monitoring zone (3,280 feet) where vessels are required to maintain 500 meters (1,640 feet) from any marine mammals and to shutdown if an Endangered Species listed marine mammal species is sighted within 500 meters.
There is a risk of entanglement with the buoy lines but the parties are expected to follow best management practices that includes using the best available technologies to avoid entanglement. A metocean buoy is currently deployed in the Morro Bay Wind Area since 2019 by the Pacific Northwest National Laboratory and there have been no incidents of entanglements. Entanglement with lost fishing gear is unlikely because most of the lost fishing gear that poses a risk to marine mammals becoming entangled on mooring lines is deployed inshore.
The Morro Bay Wind Area is critical habitat for certain populations of humpback whales and leatherback sea turtles but the displacement of prey from these areas due to vessel transits and surveys is anticipated to be short-term and temporary and not adversely impact critical habitat.
Diving birds can be impacted by active acoustic sound sources but with the directionality of sound sources, any impacts to birds diving in close proximity to a survey vessel are expected to low. Surveys will not take place in coastal nearshore areas and impacts on prey species are expected to be limited to a small portion of a bird’s foraging range.
The Morro Bay Wind Area overlaps with fishing grounds for sablefish, thornyheads, chinook salmon, hagfishes, and swordfish. Sablefish represent 23% of the value for the Morro Bay Port Complex. There may be space-use conflicts with deploying a metocean buoy but these are expected to be minor and temporary (less than 5 years) because the buoy does not occupy much area in a fishing group. Noise impacts are expected to be minimal during site characterization acoustic impacts will be shall and “there is no evidence that tissue trauma occurs to fishes or invertebrates from the energy levels emitted from foreseeable geophysical survey methods” because “fish and invertebrates use different sensory systems and primarily perceive particle motion rather than sound pressure levels.” Further investigation on noise is expected during a construction operation permit review.
Benefits to the local economy associated with site characterization and assessment are expected to be short-term and imperceptible.
In terms of cultural impacts, historic and tribal resources may be impacted by noise, bottom disturbance, and entanglements. Any discovery of a potential archaeological resource will require the leaseholder to immediately halt seafloor-disturbing activities, notify BOEM of the discovery, and keep the location confidential, and not take any action that would adversely impact the resource. Impacts are expected to be negligible.
