Home Glaciers Glacier Park finds new alignment for bridge replacement

Glacier Park finds new alignment for bridge replacement

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Glacier National Park officials met with stakeholders for the second time Tuesday afternoon to discuss the Upper McDonald Creek Bridge replacement project, a month after a contentious initial meeting left the future of the project in question. .

After four weeks of overhauling and tweaking, the new version of the project seems to meet with the approval of both parties and should start working with the deforestation as early as September 12.

“This first plan didn’t really take into account the ability of landowners to go back and forth and our communication could have been better,” said Glacier Park Superintendent Dave Roemer. “So we went back to the drawing board and considered how we could modify this design so that the project could be successful without unduly impacting landowners and their access to their land.”

The original design involved building the new bridge over the existing one, which would have severely restricted access to the west side of the creek during construction. The redesigned project now has the new bridge built approximately 30 feet upstream from the current bridge, preserving the use of the old bridge until construction is complete and the old bridge is removed.

“I think we got it right with this new design,” Roemer said. “This design balances the concerns we heard in a way that we all win. All of this reviewing of plans and coming back may have seemed a little humorous at first, but I think we got to where we wanted to be.

The planned project would be to replace the existing one-lane bridge and its two in-stream piers with a clear-span one-lane bridge with two sidewalks, one on each side. Additionally, the project would formalize parking for the Upper McDonald Creek trailhead west of the bridge, likely with 10 demarcated front parking spots. The new bridge would be approximately eight feet higher than the existing bridge.

The first bridge over the creek was built in 1926. This bridge was rebuilt in 1936 after repeated flooding. After the 1964 flood washed away the bridge, the existing bridge was built in 1965.

Severe flooding in 2006 damaged the bridge, including a crack in a central beam and the collapse of piers. Repairs over the years resulted in short-lived improvements, but the current structural condition of the bridge is considered poor with loads across the bridge limited to 15 tonnes.

“From a bridge engineering perspective, the current bridge is becoming structurally obsolete. As time progresses, the wood does not get any younger and will deteriorate more and more. Continuing to invest in the current bridge with more repairs is not the right thing to do,” said Federal Highway Administration project engineer Michael Traffalis. “It’s a good time to replace the bridge before its load capacity becomes so weak that you might be able to drive a Prius on it. We don’t want to come to that. »

Even with the new design, access to the area will be restricted and delays are to be expected.

The existing bridge would continue to be available for park service and landowner access during construction. The construction area would be closed to public access for the duration of the work. Traffic delays would be minimized as much as possible, with 30-60 minute closures expected. Complete closures, possibly for two to three days at a time, would sometimes be necessary for safety reasons (such as during crane operations).

The construction area, which extends approximately 100 feet between Going-to-the-Sun Road and the Upper McDonald Creek Trailhead, would be closed to public access for the duration of construction.

In order to mitigate impacts on wildlife, restrictions have been placed on new construction, primarily during nighttime and corpuscular hours at sunrise and sunset.

In addition, clearing work would be completed by October 1 this year to limit the impact on spring-breeding bird species.

A biological impact study conducted by the park found that the project could temporarily disturb or displace grizzly bears and Canada lynx, but the effects would not alter the large-scale distribution of either species. The Project could also disturb or displace Bull Trout, but the effects would not affect Bull Trout populations or their persistence.

“Much of the environmental compliance and analysis dates back two years, which gave us a huge advantage in being able to redesign the project. That being said, we have put a lot of work into it over the past two weeks” , said Roemer.

The replacement of the Upper McDonald Creek Bridge with a new bridge slightly offset from the existing location and alignment was approved under a Categorical Exclusion in May 2021 and the park believes the redesigned project could still be Categorically Excluded and not would not require the preparation of an environmental assessment.

The park plans to implement erosion and turbidity control to help address minor sedimentation that may occur during the project and will minimize tree removal where possible. Sensitive plant species would be salvaged for replanting.

The overall permanent impact of the project is expected to be 0.7 acres once restoration, including the existing bridge area, is complete.

A public review is underway based on the redesign to determine if there is any additional information or concerns that the park is not aware of that may require an EA.

Comments may be posted on the NPS PEPC website or mailed to the Superintendent, Glacier National Park, Attn: UMC Bridge Replacement, PO Box 128, West Glacier, Montana, 59936. The comment period ends August 30.

Journalist Jeremy Weber can be reached at [email protected]