BART, the Coast Guard and a group of experts are keeping a close eye on a barge that sank last week and currently rests on the sea floor above BART’s Transbay Tube, a Coast Guard spokeswoman said Tuesday.
The 112-foot freight barge Vengeance capsized Friday and has settled above the subterranean BART tube, which is sheltered by a 25-to-30-foot protective layer of earth, U.S. Coast Guard officials said Monday.
“It is critical to keep an eye on the forces affecting the barge such as underwater currents,” said Kyle McAvoy, a marine safety expert and naval architect with Lancaster, Pennsylvania-based Robson Forensic.
“If it’s moving due to tidal currents or if another storm were to come through and cause the barge to shift, it might create a new situation that would be of concern” regarding the tube, said McAvoy, who has not visited the site and is not involved in the recovery efforts.
“We are monitoring the situation on a daily basis,” said Loumania Stewart, a Coast Guard spokesperson.
Stewart said regular sonar scans and tube inspections are being done to ensure the BART tube is not impacted and that BART remains safe to operate.
The barge’s location “poses no threat to the Bay Area Rapid Transit District Transbay Tube or salvage operations,” Coast Guard officials said in a statement Monday.
“The owners and operators of the barge need to come up with a salvage plan with two purposes: to eliminate the pollution threat and get the barge out of there,” McAvoy said.
The barge has 4,000 gallons of diesel fuel and 300 gallons of hydraulic fluid aboard. Initially the barge was leaking, but divers managed to plug the leak Friday afternoon.
Agencies including the Coast Guard, the California Department of Fish and Wildlife’s Office of Spill Prevention and Response, the San Francisco Department of Emergency Management, Vortex Marine Construction and BART are working together to devise a salvage plan, Stewart said.
Global Diving and Salvage was hired by Vortex, the owner of the barge, to do underwater assessments and help put together the plan, she said.
“Global Diving is working with naval architects who are using information gathered from the sonar scans along with a variety of other factors that might affect salvage operations,” Stewart said.
“Some of those factors are the exact dimensions of the barge, righting movement, the tides and the weather,” the spokesperson said.
“It can take up to several weeks to determine a salvage plan,” Stewart said.
Coast Guard Station San Francisco crews are enforcing a safety zone in the area to ensure safety for those responding to the capsized barge.
The Coast Guard also issued a safety marine information broadcast to local mariners.
No impact to the shoreline or wildlife has been observed, but shoreline teams and crews are monitoring the area, according to the Coast Guard.
The barge, which is usually moored at Treasure Island, is part of work that is periodically done to prevent corrosion in the Transbay Tube, BART spokesperson Alicia Trost said last week.