One offshore wind developer will begin mapping the seafloor off the coast of San Luis Obispo County this week.

Golden State Wind is one of three corporations that holds a lease to build floating wind turbines in the 376-square-mile Morro Bay Wind Energy Area about 20 miles away from Cambria and San Simeon.

The company will launch its site survey process on Monday, according to a Golden State Wind news release.

The three leaseholders will use sound surveys to find out what the seafloor looks like, including where sensitive habitats and shipwrecks are located, the consistency of the soil and the depth of the ocean floor. They will use that data to decide where to anchor floating platforms for the wind turbines and where to place cables that will carry electricity to land.

“Golden State Wind will employ survey data for engineering and permitting a proposed offshore wind energy installation, ensuring project designs that avoid and minimize potential impacts by reducing physical and biological disturbance of marine resources and wildlife,” Golden State Wind CEO Tyler Studds said in the release.

Go Adventurer, a 205-foot vessel, will carry scientists and survey equipment to Golden State Wind’s lease area — which is about 53 miles northwest of Morro Bay.

The vessel departs from Port Hueneme in Ventura County and will return every 28 days to pick up a fresh crew.

Go Adventurer will not dock in Morro Bay Harbor or Port San Luis, the release said.

Golden State Wind is the second lessee to start its site survey process. Atlas Wind, owned by Equinor, launched its site surveys in federal waters in mid-April, according to an Equinor spokesperson. This effort will be completed in early August.

Equinor is using two vessels for the surveys: a 340-foot offshore vessel that operates out of the port of San Francisco and a 45-foot nearshore vessel that operates from a local port, according to a fact sheet from the company.

Invenergy, which owns Even Keel Wind, plans to start site surveys next year, a company spokesperson said.

Site surveys to map the seafloor

Golden State Wind will use three types of equipment to map the seafloor, including a multibeam echosounder, a side scan sonar and a sub-bottom profiler, according to the news release.

The equipment emits pulses of sound that create images of the seafloor.

The equipment will be attached to an autonomous underwater vehicle, which carries the surveying tools from Go Adventurer to about 20 meters above the seafloor, according to the Golden State Wind website.

The sound is emitted at a pitch that doesn’t harm marine mammals, according to the release. Meanwhile, the sound is beamed down from the vehicle in a narrow pathway to limit its impact on the marine environment.

“Survey technology used in offshore wind is very different from seismic airguns used in oil and gas surveys and sonar used in tactical military operations emitting lower noise at higher frequency and narrower beamwidth,” Studds said in the release.

Atlas Wind also used a multibeam echosounder, a side scan sonar and a sub-bottom profiler for their site surveys, according to the company’s website. Only the sub-bottom profiler operated at a noise level and frequency that could be heard by marine wildlife.

“The sub-bottom profiler falls in the range of hearing of some animals, but the size of the area which is impacted by the sound is very small, either because the sound beam is very narrow, or because it is operating very close to the seabed,” the website said. “This nearly eliminates the potential for exposure of animals — an animal would need to be swimming right under the equipment to be exposed to this sound.”

The equipment is permitted by the California State Lands Commission Low-Energy Offshore Geophysical Survey Permit Program, and it is routinely used by federal agencies and academic and research institutions, the release said.

To protect marine life, Golden State Wind and Atlas Wind vessels will limit their speed to 10 knots and remain at least 500 meters away from marine life.

Meanwhile, trained observers will watch for marine life and will halt the vessel if they spot a protected species.