Amid a multimillion-dollar study, the Army Corps of Engineers anticipates expanding the Mobile Ship Channel would have little ecological impact on Mobile Bay, but local environmentalists believe that’s too good to be true.

The Corps’ Mobile District is about halfway through evaluating the potential economic and environmental impacts of deepening and widening the federal shipping channel. About 36 miles long, it has a current depth of of around 45 feet.

However, while the sizes of vessels in the global shipping industry have grown, officials at the Alabama State Port Authority say the channel they use when calling on Mobile has not.

ASPA President and CEO Jimmy Lyons said the state made “some strategic decisions” about a necessary depth when constructing a container terminal in 2005 based on what, at the time, were thought to be the largest ships the port could see for several decades.

“We were wrong. We got caught flat footed,” Lyons said. “We have ships we’re handling today that are 30 percent larger than that, and we expect far larger ships in the foreseeable future.”

For shipping companies, which Lyons called the port’s “ultimate customers,” there can be great benefits to using larger ships because they reduce the number of trips necessary to move goods.

Congressional approval and funding will be needed to move forward with any expansion, but the Corps’ current evaluation is based on a proposal to deepen the channel to 50 feet while widening a five-mile stretch 100 feet to create a passing lane for faster-moving ships.

Expanding the channel would require additional dredging, and the resulting increase in the size and frequency of ships visiting the port would have some effect on Mobile Bay. The Corps has been studying those potential effects.

The study has focused on how “major environmental resources” could be impacted, factors including wetlands, submerged aquatic vegetation and benthic invertebrates that make up the basis of the food chain, as well as aquatic life such as fish and oysters.

According to environmental engineer Jacob Berkowitz, there are roughly 77,000 acres of wetlands around Mobile Bay and, based on the Corps’ initial projects, he said any impact to those would be minimal if the shipping channel were expanded today.

During a public meeting in late February, Berkowitz gave a similar forecast on how those other “major environmental resources” would fare during and after a five-foot expansion even when considering the possibility of future sea level rise — something the Corps is required to do.

“Given the best available resources and applying our cutting-edge scientific approaches, we predict no major impacts or loss of resources if this project were to be built, and that’s across all five of those areas that we know are important,” Berkowitz added.

Theoretically, environmental groups such as Mobile Baykeeper should be pleased to hear that a large and controversial project won’t have negative effects on the area’s ecosystem.

However, Executive Director Casi Callaway says it’s actually been “worrisome” for her and others concerned about possible environmental impacts from the channel expansion because “finding no measurable impacts” would negate the need to discuss possible mitigation efforts.

Callaway said Baykeeper has been researching similar projects in shipping channels throughout the Southeast and have found none without environmental impacts.

“It will change the nature of Mobile Bay. The question is to what extent,” she said. “It’s just not possible that there are zero measurable impacts on five out of five of the areas they’re studying. It just isn’t true, and saying that makes the community question the veracity of the entire study.”

Callaway said she doesn’t have any reason to believe the Corps is being intentionally misleading, but said the preliminary information presented on Feb. 22 was “a simplification” that provided no specific information for the public to consider or question.

It’s important to note the meeting last month was the first and only town hall-style public meeting — where citizens are permitted to ask questions from the floor — the Corps has scheduled since it began studying options for a channel expansion nearly four years ago.

While the Corps has had several public meetings in an “open house” format, Baykeeper and other groups repeatedly requested a town hall-style meeting so they could ask questions and receive answers publicly instead of in one-on-one interactions with members of the Corps’ team.

The next step in the process is the release of the Corps’ draft of the supplemental environmental impact statement, scheduled in June. Though the document will be open for public comment, Callaway said she’s hopeful the Corps can schedule another public meeting before that occurs with a “deeper level of detail.”

Despite concerns with early information from the Corps’ study, District Commander Col. James A. DeLapp said he and his staff “fully understand the importance of the environment.”

“This is second largest delta in the United States,” he said. “Mobile Bay is a gem and a resource that we want to make sure we’re good stewards of.”