By Tracy Correa
With the help of trained protected-species observers — or “spotters” – on both boat and plane, PG&E will take extra measures to protect marine life while conducting proposed offshore seismic testing near Diablo Canyon Power Plant.
The high-energy seismic surveys were approved by the California State Lands Commission Aug. 20 and could begin this fall if all the necessary permits are obtained from local, state and federal agencies. They will take place in the Pacific Ocean near the shores of the nuclear power plant in San Luis Obispo County.
“We are doing an awful lot to protect wildlife in the area,” said Jearl Strickland, PG&E’s director of nuclear projects. He said the goal is to conduct the tests in the most careful and thoughtful way possible.
A week before testing begins, trained spotters will take part in aerial canvassing to look for marine wildlife in the area; the testing area could potentially be adjusted based on the presence of marine mammals. These trained observers also will be present on survey boats throughout the testing process, looking out for whales, porpoises and sea otters.
Both 2D and 3D seismic work
PG&E’s advanced seismic research was called for by the state and accelerated following last year’s accident at the Fukushima Daiichi power plant in Japan that followed a massive earthquake and tsunami.
The seismic mapping work includes the use of a combination of on-shore 2D and 3D studies, off-shore 3D low- and high-energy surveys as well as the ongoing use of seismic-monitoring devices.
PG&E has made steady progress toward completing these studies since 2010. The onshore work is nearly complete, the majority of the 3D low-energy offshore studies are finished, and the California Coastal Commission has approved the request to install ocean-bottom seismometers to detect seismic activity.
With PG&E seeking approvals to conduct the final high-energy study, concerns have been raised about the affect the survey’s high-decibel sounds will have on marine life. PG&E is mindful of these concerns, Strickland said, and is making every effort to mitigate potential impacts.
Other companies – including those in the oil industry — have used similar testing safely, he said. However, he said not all have taken the same “multi-tiered monitoring program” approach that PG&E has planned to protect marine life.
‘Above and beyond’
“We are going above and beyond what other companies have implemented to date,” he said.
For example, before a survey track begins, a single air gun will sound at a low-level to warn marine life before ramping up to full power. The air gun sound will be managed or reduced based on the proximity of marine mammals to the survey boat. During the survey, a 180-decibel exclusion zone, and an even larger 160-decibel safety zone, will be established around the boat for the protection of marine mammals. The zones were established with help from the National Marine Fisheries Services.
If marine mammals appear likely to enter the 180-decibel exclusion zone — a 1.1-mile ring around the boat — then other mitigation efforts will kick in, including powering down of the sounding equipment or suspension of the work. And if the mammals enter the larger 160-decibel zone –a 3.8-mile ring around the boat — they will be monitored by one of the trained spotters and either the boat speed or course will be altered to avoid them.
Acoustical and infrared equipment on the research and supporting vessels also will be used to monitor for marine life.
In addition to the National Marines Fisheries Services, PG&E is working with U.S. Fish and Wildlife Service, California Department of Fish and Game and the U.S. Geological Survey.
End of year timing
If PG&E receives needed approvals, a portion of the testing will occur during November through December of this year and the same time period in 2013. This is a time of year when there are the fewest number of marine mammals off the Central Coast. It also a low fish larvae period. And PG&E will evaluate the process along the way to ensure that the mitigation efforts are effective and will make appropriate modifications when necessary.
Understanding that these high-energy studies could impact local commercial fisheries, PG&E also is engaged in ongoing discussions with fishing representatives and has presented them with an offer of compensation that exceeds the value of their average gross catch during the fall season dating back to 2006. PG&E has an established claims process in place for all parties that are potentially impacted by the work. Potential claims will be fast-tracked and the process will be managed locally.
The results of the surveys are expected to provide significant information.
The studies will provide an accurate and detailed picture of the seismic characteristics of the area and add to the library of seismic knowledge that PG&E has amassed in recent decades through its long-term seismic studies program. They’ll help validate the seismic design of Diablo Canyon Power Plant.
Additionally, the detailed findings – the angle of the faults, how they are shaped and the amount of ground motions they’re capable of producing — will be shared with local public and government agencies. The information will enable these agencies to update emergency preparedness plans, if needed, and to ensure the safety of critical infrastructure. The data also will be used to support federal requirements for new seismic risk evaluations following the Fukushima Daiichi incident.
Strickland said the studies are necessary: “It’s critical that PG&E is maintaining not only nuclear safety, but safety to those in our communities.”
Email Tracy Correa at email@example.com.