A proposed plan to widen Mobile’s federal shipping channel has stirred up a 20-year-old conversation about beach erosion on Dauphin Island.
The project, which won’t get started for another year, plans to widen a five-mile section of the channel by 100 feet.
Currently, the channel is 400 feet wide and required to reach a depth of 45 feet, but the vessels transporting steel, coal, containers and petroleum to and from Mobile can be up to 165 feet wide. Alabama Port Authority CEO Jimmy Lyons says passing slower-moving ships is dangerous for vessel pilots.
“We already have to hold out ships that want to come in,” he said. “Sometimes they have to wait six or seven hours while another ships comes out. A port our size should be 550 feet wide throughout the entire channel, but that’s a steep hill to climb.”
That wait time is in addition to the three and half hours it typically takes to move through the 36-mile channel.
According to Lyons, a ship’s inability to pass along the channel doesn’t cause the ASPA to lose money, but does create a problem with efficiency.
The expansion of the channel is also necessary because of an increase in the number of “post-Panamax” vessels, which will begin moving though an expanded Panama Canal in 2015.
The additional width was originally planed to start just south of McDuffie Island, but was moved to an area beginning at Fort Morgan and moving north for cost efficiency and safety reasons.
“That section of the channel is prone to naturally keeping itself dredged out because of the current,” Lyons said. “So there’s no ongoing maintenance cost.”
The change in location will reduce the project’s $40 million price tag to $15 million, but it also creates an opportunity to straighten out two bends in the channel the port authority says can be dangerous to navigate.
The cost will be split between the U.S. Army Corps of Engineers, which will pay 75 percent and the ASPA, which will pick up 25 percent of the tab.
The issue of erosion stems from the maintenance of a federal channel, which requires routine dredging to maintain a safe depth for vessels.
The USCOE maintains federal shipping channels with assistance from a local sponsor in the area. In Mobile’s case, that sponsor is the ASPA.
The USCOE already spends $25-30 million each year dredging sections of Mobile’s main shipping channel and the smaller channel in Theodore.
Since 2000, the USCOE has been accused by some of contributing to the erosion of Dauphin Island through that routine dredging.
After more than a decade of litigation with Dauphin Island Property Owners Association (DIPOA), the issue is still contested by some.
“The way we see it, the ship channel is an integral part of the local, state and national economy, and it’s not going anywhere,” said Dauphin Island Mayor Jeff Collier. “However, it does disrupt the normal flow of sand from east to west.”
That disruption is what DIPOA indicated as the cause of hundreds of feet of beach erosion on the west end of the island, which was one of the issues raised in the lawsuit.
A federal judge ultimately approved a settlement that resulted in $1.44 million from the USCOE and an additional $60,000 from the state government.
The settlement also required the Corps to conduct its own study of the erosion on Dauphin Island and its contributing factors.
“The study was the result of the settlement agreement, which the state of Alabama cost-shared with the Corps,” said Dr. Susan Rees, who was the chief of a Coastal Environment Team for the USCOE when the report was created. “The judge selected the head researcher and the panel who would review it for accuracy.”
The study, which was released in 2010, analyzed historical shoreline and bathymetry data, dredging records, tropical cyclone records and other costal processes dating back to 1853. In simple terms, the report determined the erosion was a result of the nature of Dauphin Island and exposure to strong storms over time, not the dredging of the Mobile shipping channel.
It found that “major changes in island configuration west of Pelican Island were always associated with hurricanes or tropical storms.”
Since 1990, the Corps has dumped the material it has dredged southwest of the Sand Island Lighthouse in an area referred to as the Sand Island Beneficial Area (SIBA).
From there it eventually flows westward to Dauphin Island. Rees said it does get there, but it doesn’t get there very fast.
“Theoretically, that area was chosen so (sand) would continue to migrate toward Dauphin Island. We don’t necessarily agree with that,” Collier said. “We question whether it makes it that far.”
Collier said the town of Dauphin Island has worked with its own coastal engineer, Scott Douglas, who maintains the SIBA is too far south. He said the dredge material would be more helpful in rebuilding the western beaches if it were placed closer to the lighthouse area to the north.
The issue with that proposition is a congressional requirement to dispose of dredge materials in an economical manner. Moving it further would mean an increase in cost.
There’s also a lack of “beach quality” sand in some areas, which Rees said goes back to the geologic evolution of the Mobile Bay.
“About 5,000 or 6,000 years ago, the sea level was much lower. The bay would have looked like a river with an extensive flood plain,” she said. “The sedimentary nature of the whole area was mud and clay.”
Mobile’s is the second-largest estuary in the country, which means tons of sediment from its five rivers have been deposited in the Bay over time.
According to Rees, dredging digs down into that old material, which isn’t suitable to be dumped on a beach.
Currently, the channel widening is waiting on the results of a $1.3 million environmental assessment for its new location. Lyons said study should take less than a year, and he hopes the project will be wrapped up sometime in 2016.
As for Dauphin Island, Collier said this would be a good a time as any to address the best location for dredge material dumping.
The town has already planned a mile of beach restoration on the east end of the island through the Coastal Impact Assistance Program, which is only waiting on a permitting process.
Another project to help restore as much as four miles of beach on the west end is also planned, but has yet to be funded.
However, Collier thinks the federal government and state of Alabama should have a vested interest in the sustainability and security of Dauphin Island.
“The island plays a roll as a barrier to everything in the north – the salt marsh, the oyster beds and the mainland,” he said. “If Dauphin Island were to wash away, particularly on the west end, there would be salt water inclusion into several areas that couldn’t handle it.”
He said the money put into restoring the island could help save the government money when it comes time to pay for hurricane restoration projects in the Gulf — calling it a decision of “paying for it now, or paying for it later.”
This page is available to subscribers. Click here to sign in or get access. During the month of December, give (or get) a one year subscription with TWO months FREE.