From Bay Mud to Building Material, From Lockdown to Smooth Sailing

DREDGING: From Bay Mud to Building Material, From Lockdown to Smooth Sailing

Ariel Rubissow Okamoto

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Download: Estuary News, October 2013 PDF

With so much of San Francisco Bay so shallow, the U.S. Army Corps of Engineers has long had to dredge out channels and harbors so ships don’t run aground, an activity not without its ill effects on the ecosystem. In the 1980s, fishers complained about turbidity driving away their catch – both from the dredging activity itself and from the dumping of the material back into the Bay at more than a dozen aquatic disposal sites. At the same time, water quality watchdogs worried that all the scooping and dumping not only stirred up long-buried contaminants but also re-suspended and redistributed them. To make matters worse, the depth finder of an inbound ship, out in the main Central Bay shipping channel, suddenly flashed “0” one day. A 72-foot mound of dredged material had accumulated just 30 feet below the surface at the Alcatraz disposal site.

Suction hopper-dredge Essayons. Photo courtesy USACE

By the time dredgers, fishers, regulators, and ports sat down at the CCMP negotiating table, the region was in the midst of a “mudlock.” To help break it, regional interests and the San Francisco Estuary Partnership underwrote the first serious research on how turbidity affected fish, and whether dredging activities disturbed bottom dwelling organisms. They also began studying how quickly sediment dispersed from disposal sites, and where it ended up. At the time, no one could have imagined that the region would be even more obsessed with what any layperson would call “mud” 20 years later.

“Dredged material has gone from something called a ‘spoil’ to something viewed as a resource,” says Al Paniccia of the US Army Corps of Engineers. “It’s now considered so valuable, nobody wants it to be hauled off to a deep ocean site for disposal anymore. There’s been a 180-degree change in attitude.”

Paniccia is one of four managers from key agencies who now work together to manage Bay dredging. But they weren’t working together yet in 1993, during the mudlock. Back then, 80 percent of the dredged material was put back in the Bay at various sites, only the most contaminated materials were placed on upland sites, and there was no EPA- approved ocean disposal site as there is today.

Enter the CCMP process. Participants set straightforward goals: eliminate unnecessary dredging and manage waterway modification to offset adverse impacts. To accomplish these goals, the Corps, BCDC, the Regional Water Quality Control Board, and port representatives worked with the fish and wildlife agencies that had to be consulted about impacts to endangered species on a long term management strategy for the placement of dredged material in the region (“LTMS”). The strategy called for reducing disposal in the Bay to 20 percent by 2013, and for maximizing the beneficial reuse of dredged material – another CCMP goal.

“The CCMP called for a new management strategy, and for putting in place a strong sediment testing program, so we created a cooperative program to manage it all, the LTMS and the DMMO,” says BCDC’s Deputy Chief Steve Goldbeck, referring to the one-stop interagency Dredged Material Management Office. The office was set up with input not only from the agencies issuing dredging permits, but also from the ports and marinas trying to get them, represented through the Bay Planning Coalition. “We really worked hard to deliver on all the promises we had made,” says Goldbeck.

Another accomplishment was agreement on “environmental work windows” over the course of the year. In these week-by-week windows, dredging activities could proceed with fewer hoops to jump through than at other times when fish and wildlife might be more sensitive, such as when birds are breeding or salmon migrating.

Between the LTMS, the DMMO, and the windows, dredgers got a lot more clarity on how they could proceed, and wasted less time idling expensive equipment. Further clarity came from strong research and analytical work on the part of US EPA, the Water Board and regional water quality monitoring programs (see insert) to develop clear sediment testing guidelines, and sediment quality objectives for beneficial reuse. Knowing which materials were too contaminated to put back in the Bay really settled fears about making contamination worse.

“Our dredging program runs so much more smoothly these days because of interagency partnerships we’ve developed over the years through LTMS,” says Paniccia. “Our permitting process and sediment testing are pretty streamlined and straightforward now – we all know what we’re doing. We don’t always get to dredge in the window, but even dredging outside the window isn’t a crisis anymore.”

The results have been encouraging. A newly published 12-year LTMS review found that all targets for reducing in-Bay disposal volumes were met – decreasing from 80 to 20 percent. More than 44 percent of the material dredged from the Bay was beneficially reused in restoration projects, ranging from building beaches and raising wetland elevations to providing the muddy foundations of new eelgrass beds. In addition, more than 80 percent of dredging and disposal activities are now completed within the windows protective of wildlife.

Looking ahead, many challenges remain – despite the significant accomplishments in this CCMP program area. One federal policy, for example, could do with an update more in tune with regional priorities. The policy requires the Corps to always chose the “least cost environmentally acceptable” alternative for dredged material disposal. Unfortunately the more you handle the material, the more it costs. So moving it from the Bay bottom to a transport scow to an off loader, and then finally pumping it miles across mudflats onto a wetland is costly, especially with diesel fuel now so much more expensive.

“It’s a double whammy,” says Goldbeck. “The Corps no longer has enough money nationally to dredge even critical channels, and lots of small harbors that support small fishing fleets don’t get dredged at all.”

With the fierce competition for each smaller sequestered dollar, as well as least-cost policy obstacles and skyrocketing fuel costs, the Corps struggles to help the region make the most of its mud. In the coming year, however, the Corps will be able to beneficially reuse some sediment from its annual Oakland Harbor dredging project through an innovative placement strategy. “By allowing some material to go in-bay, we’ve been able to offset the cost of taking some material upland, so in that way we can comply with federal standards but still be flexible enough to help with restoration,” says Paniccia.

What LTMS agencies remain most concerned about today is the loss of federal funding to sustain the extraordinary science and monitoring programs that have helped all stakeholders feel comfortable with the impacts of dredging in the Bay. As vast new wetland restoration sites clamor for more mud to fill up subsided salt ponds and diked baylands so they can keep pace with sea level rise, most stakeholders are starting to feel no material at all should be “wasted” by being dumped at the ocean disposal site. But at what cost, and to whom? Working out such thorny multi-objective issues sounds like grist for future CCMPs.

Projects Implementing Dredging Actions: Lots

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