Boardman Dam Removal Set For Spring

Another major phase of the Boardman River Dams Project is ready to get underway as crews prepare for the estimated $8 million removal of the Boardman Dam and old Cass Road bridge this spring.

Carl Platz, project manager with the U.S. Army Corps of Engineers, says the group is finishing reviewing bids for the project this week. “We’re anticipating awarding a contract at the end of this week or early next week,” he says. While the project’s final budget and construction timeline will be determined by the contract, Platz says previous estimates of $8 million should be “on target.” The majority of project funding is coming from federal funding, with a small handful of grants and local funds making up the rest, says Platz.

According to Implementation Team Chairman Frank Dituri, work could begin as soon as early spring. “The most recent update is that the project should be completed by the end of September or October,” he says.

Phase Two, as this stage of the Boardman River Dams Project is called, will complete work that began in 2016 with the $3 million construction of the new two-lane Cass Road bridge. That bridge is still connected to the old one-lane river crossing atop the Boardman Dam that connects Cass Road to Keystone Road. For 2017, planned work includes rerouting the Boardman River to flow under the new bridge, deconstructing and removing the Boardman Dam and old bridge, and restoring the missing roadway so that Cass Road maintains two lanes of traffic all the way to Keystone.

“Since we already had Cass Road closed last year, we modified the intersection at Cass and Keystone at that time, changing out the signals and widening the road so there was more room for (vehicle) stacking,” says Grand Traverse County Road Commission Manager Jim Cook. “We did that so the intersection would be ready and so we didn’t prolong the impact of the 2017 project. We wanted to get the road back open as soon as possible this year.”

The project will still require Cass Road to be closed again for a significant period of time, however – likely for the entire summer, and possibly longer. “In terms of inconvenience for the local population that uses Cass, it’ll be similar to 2016,” says Cook. While officials tried to time the closure this year to avoid impacting Traverse City Area Public Schools as much as possible, work could still “impact some portion of the spring or fall,” Cook says.

When the project is finished, however, traffic capacity on Cass will be nearly tripled. “On the old bridge, we averaged 5,500 cars a day,” says Cook. “The new bridge will accommodate 14,000 or 15,000 cars a day. So it’ll be a huge improvement once we can get that old bridge out.”

Project engineers have also taken pains to avoid any drawdown disasters like the one that occurred during the removal of the Brown Bridge Dam in 2012, when the failure of a drawdown structure resulted in the flooding of 66 properties along the Boardman River. AECOM Project Engineer Dan DeVaun says the Brown Bridge project – which was overseen by two different firms, AMEC Engineering and Molon Excavating – relied on a temporary dewatering structure next to the dam that failed. “When it failed, there wasn’t any stop gap or failsafe for it,” DeVaun explains.

For the Boardman Dam, crews will instead use a bypass dewatering system, which diverts water over the dam gradually in a series of pipes. Once water levels are at a safe elevation, the dam will be excavated. In a worst-case scenario – a total failure of the system or a deluging rain event – Keystone Pond would simply fill back up, says DeVaun, requiring the drawdown process to begin again. “The worst-case scenario is really a delay in time,” he says.

While Phase Two gets fully underway this year, project team managers will also be looking ahead to Phase Three: the removal of Sabin Dam in 2018. The design phase for that project is 60 percent complete now, according to Platz, with bids likely going out in late 2017. In a January 23 memo, the Army Corps announced that the planned route for the restored Boardman River channel near the Sabin Dam is being relocated 150 feet west to “provide a more stable alignment.” While a small shift geographically, the new river route now goes “exactly where the powerhouse is,” says Platz, requiring its removal.

That news will likely be welcomed by local officials, who hoped to see the powerhouse removed to eliminate upkeep and maintenance costs but were initially told by the Army Corps its removal wasn’t necessary to the project’s success. Instead of Phase Three’s early estimated price tag of $2.7 million, removing Sabin Dam – including the powerhouse – will likely now cost between $4.2 and $4.4 million, according to Platz.

However, with the Great Lakes Fishery Commission stepping in to help with the final phase of the dams project – future modifications at Union Street Dam – federal Army Corps funding assigned to that phase can now be used at Sabin instead. The budgets will essentially “balance out,” says Platz. Of the up to $4.4 million cost for the Sabin project, an estimated third of the funding – in the neighborhood of $1.5 million – will come from local sources, he says. The rest will be covered by federal funds.

When finished, the Boardman River Dams Project is expected to reconnect more than 160 miles of “blue ribbon” stream and reestablish the cold-water aquatic ecosystem of the river.

Pictured: Boardman Dam/old Cass Road bridge. Photo credit: John Russell/Great Lakes Images LLC.