Machias dike's risk of failure changes DOT plans

After years of delay and debate over the type of structure that will replace the Civil War era Machias dike that bridges Route 1 over the Middle River, recent signs of increasing risk of failure of the structure have prompted the Maine Department of Transportation (DOT) to pivot from its previous recommendation to build a bridge and go all in on building a replacement dike instead. Because of the safety risk, some shoulders along the roadway were closed off this week, and two temporary bridges will be installed over the dike in the coming weeks.
"As town manager, I am thrilled that a decision has finally been made," says Bill Kitchen, Machias town manager. "This has been going on for so long."
The DOT originally identified the dike for replacement back in 2009. In 2017, DOT rated condition of the dike at a four out of nine, with nine being the most stable. The low rating was because of the number and severity of cracks in the structure, missing concrete and wood and exposed and corroded steel. DOT then announced its intention to build an in kind replacement of the dike in 2018, a decision that held until two years later, when NOAA and other federal agencies intervened to press the consideration of building a bridge instead of a dike.
Prior to the dike, completed in 1868, the Middle River hosted a 300 acre salt marsh. Salt marshes are considered rare and invaluable habitats for native species, including commercial and recreational fish. If a bridge were built in place of the dike, it would lead to the largest salt marsh restoration in the state. It would also have helped ameliorate concerns about rising sea levels in the coming decades.
But a bridge would also cost more, and dozens of homes and farms would be vulnerable to flooding if the dike were removed. Others, such as Marshfield resident Wayde Carter, asserted that the bridge didn't significantly impede fish travel and that the removal of the dike would effectively shock the habitat with a sudden influx of saltwater. Despite the concerns raised by affected property owners and those who asserted that the bridge would cause more problems than it fixed, the DOT announced last year that a bridge was the route it was taking.

Cracks in the plan
The DOT's position started to change as the failing condition of the dike became increasingly apparent. A year and a half ago, a "significant dip" developed on the dike, Kitchen explains, prompting him to alert the DOT. The DOT came out to inspect the structure and make a minor repair to stabilize the dip. Since then, inspectors have returned periodically to monitor the dike's deteriorating condition.
In September, inspectors noted areas of particular concern, with "increasing voids developing," according to a press release from the department. Last week, divers "observed new areas of soil loss between the concrete slab and the timber that forms the top of the gated boxes."
"They finally said, 'Yeah, it's failing now,'" Kitchen says.
Rather than continuing to push for a bridge that comes with a higher price tag and potential for flooding dozens of properties, DOT made the decision to build a replacement for the existing dike, given the rapid rate of failure.
"While MaineDOT realizes that some stakeholders may prefer a bridge alternative and tidal restoration, the department believes a fully gated culvert alternative will best meet the project's purpose and need," the release states. "This alternative will improve the structure's condition, maintain the Sunrise Trail, provide for future rail use and avoid flooding hundreds of acres of land."
As to how residents will respond, Kitchen says, "Not everyone is going to be happy. Some landowners side with the dike, and then there are those who wanted the free flow of water to be reinstated."
For his part, Kitchen says, "I'm glad that we've gotten to this point where a proactive step is being taken, as opposed to getting to the point of failure first."
In response to the increasing risk of failure of the dike, the department closed off an area on the shoulder and parking area of the roadway on November 7. Within the next few weeks, a set of two temporary bridges will be brought in and installed over the dike. While those two bridges are being installed -- a project expected to take a week's time -- traffic will be diverted.
As to where the detour may be, Kitchen says it will likely be one of two options: Hadley Lake Road to Ridge Road through Marshfield and then onto 192, or via Route 92 through Rim Road and Machiasport and then back onto 92. The detour will be inclusive, Kitchen says, with passenger, commercial and emergency vehicles taking it for that week.
The temporary bridges are likely to be in place for years, Kitchen says. Design on the dike will be taking place in 2024, with constructed anticipated in 2025 "if we're lucky."
Kitchen's hope is that the new design elevates the finer points of the dike and its role in the area. "This is not a simple piece of infrastructure," he says. "It is an economic asset, a cultural asset, a recreational asset. As such, it should be stunning."
The new dike could have more defined space for vendors, Kitchen suggests, as well as separate lanes for ATVs and bicycles.
"We, as a community, have had very little input as to what it will look like under the surface," Kitchen says. "What we should focus on now is the surface of the dike. I truly believe this project can win awards for DOT and for the state."
The cost of the temporary measures of the new dike have not been provided or estimated yet by the DOT. The 2018 design was estimated to have a price tag of $2.4 million, with a two and a half year construction time.
DOT will be preparing an environmental assessment under the National Environmental Policy Act over the coming months. In early 2024, the environmental assessment will be presented for public input. For additional information on the project over the course of its development, visit www.maine.gov/mdot/projects/machiasbridge.