Army Corps: Dredging not unhealthful

Concerns raised over silt’s content, odor

The dredging of Crescent City Harbor’s federal channel has been long awaited, but it is causing some residents, including a local representative of a surfing organization, to wonder if it poses a health problem.

After nine years of silt buildup that forced some boats to arrive and depart only at higher tides, the Army Corps of Engineers started dredging critical portions of the channel recently.

Part of the process is depositing the dredge spoils on Whaler Island, meaning some of it ends up on South Beach.

Some harbor residents have complained about the smell and voiced concerns that the spoils may contain harmful substances.

Ed Keller, Army Corps of Engineers environmental manager, said the black sludge pouring from the pipe on Whaler Island may smell bad, but isn’t unhealthy.

“The problem is that the channel hasn’t been dredged in nine years,” said Keller. “It’s a low-oxygen environment and there has been a significant buildup of material.”

Keller said that anaerobic bacteria, which thrive in low-oxygen environments, are breaking down sulfites into hydrogen sulfide gas that smells sulfuric like rotten eggs.

“It’s producing the smell as the harbor bottom is dredged up and deposited,” said Keller. “Once it’s deposited the smell should clear off very quickly due to oxygen being added to the system.”

Due to the length of time since the last dredging, the Corps conducted a battery of tests “to fully analyze the make-up of the channel’s bottom,” he said.

“We found that it was about 80 percent sand with some fibrous material that has proven not to be a problem,” Keller said. “But other than that it was absolutely safe, and completely normal.”

That hasn’t eliminated the concerns of Mike Sweeney. The representative of the local chapter of the Surfrider Foundation raised questions about the health risks of the harbor dredge spoils, and said he is unconvinced.

“There’s black stuff on the beach and in the lineup,” Sweeney said, referring to the area off South Beach where surfers wait for waves. “Not to mention all the diesel fuel, dioxins and seal excrement layered into that sand. The least they could do on calm days is post a warning on South Beach that the water may be hazardous to people’s health.”

Sweeney said that there hadn’t been any documented health problems from the dredge spoils, and that the Surfrider Foundation had double-checked that all the permits were in order.

“It just worries me that whatever contaminants are mixed with that sand are now being released onto South Beach,” Sweeney said.

But Keller said experts agree there is no threat.

“We went further with our original analysis than normal because it had been so long since it was dredged,” Keller said. “And both the California Water Quality Control Board and the Environmental Protection Agency have concurred with our findings.”