WEST GLACIER, MONT. - Officials at Glacier National Park announce that the Environmental Assessment (EA) for the McDonald Creek Bank Stabilization at Milepost 19.25 on the Going-to-the-Sun Road and Statement of Findings for Floodplains are available for public review and comment.
In November 2006, Glacier National Park experienced a storm that resulted in 9.1 inches (23.1 cm) of rain in a 36-hour period. This event caused multiple creeks within the park to swell above their 100-year-flood stage, causing notable damage throughout Glacier.
Emergency repair took place on several sections of the Going-to-the-Sun Road (Sun Road). At Milepost 19.25, measures were taken to stabilize unconsolidated soil along the bank of McDonald Creek. This was a temporary action to prevent further damage to the road and keep it open for visitor traffic the following year. Permanent stabilization of the bank is necessary at this time to prevent further erosion and other damage to the Sun Road at this location.
Three alternatives, including a no action alternative, are evaluated in the EA. The alternatives address factors associated with bank stabilization, such as erosion and sedimentation, bull trout-rearing habitat, protecting the historic Sun Road and stream hydraulics.
Alternative I, the ‘No Action’ alternative, would leave in place soil nails that were installed to stabilize unconsolidated soil along the bank of the creek and let the site grow back naturally. No other actions would be taken to prevent further erosion.
Alternative II would place two rock barbs in the creek and stabilize the slope with rock riprap and the planting of suitable vegetation. Rock barbs are structures made of rock riprap that protrude from the bank upstream to decrease velocity of the stream by reducing speed and deflecting water from the bank, thus preventing additional erosion.
Alternative III, the environmentally preferred alternative, would stabilize a larger area by using rock riprap only (no barbs). Vegetation would be incorporated into the riprap.
Both Alternative II and Alternative III would require machinery in McDonald Creek for about two weeks. This work was not analyzed in the 2003 Going-to-the-Sun-Road Rehabilitation Plan/Final Environmental Impact Statement. Therefore, an EA has been prepared.
This EA will be on public review for 30 days and is also available online at the park’s planning website (see address below). Please provide comments by Friday, Sept. 19, 2008.
Comments can be provided directly through the park’s planning website. Go to https://parkplanning.nps.gov/glac and select this project. Comments can also be sent by mail to: Superintendent, Glacier National Park, Attention: Bank Stabilization EA, P.O. Box 128, West Glacier, MT 59936.
- NPS -
Source: U.S. Department of the Interior, National Park Service
