Flathead National Forest officials are seeking public input on a number of repairs that have been proposed for an aging dam on Lion Lake near Hungry Horse.

The project would require an unspecified amount of water to be temporarily drained from the reservoir beginning in May.

Originally constructed by the Bureau of Reclamation in the late 1940s, Lion Lake Dam is long overdue for rehabilitation work, according to the Forest Service’s website. The agency, which took over ownership of the dam soon after it was built, started developing a plan a few years ago to address various seepage problems.

While Lion Lake has two dams, the agency will focus its efforts on the larger primary dam at the south end of the 35-acre lake, which flows into Whelp Creek and feeds into the South Fork of the Flathead River.

According to a March 8 scoping letter from Hungry Horse District Ranger Robert Davies, the Forest Service plans to slip-line the existing outlet pipes on the lake side of the dam, install a chimney and toe drain to handle seepage, remove the existing outlet pipe headwall, replace the outlet gate and rebuild the dam’s embankment, among other tasks.

Construction is slated to begin in August and is estimated to cost around $500,000. A contract has yet to be awarded.

Once crews break ground, the lake’s entire dam system will be shut down for public safety purposes, though a news release on the project states the agency would strive to keep public access open at the north recreation area and various existing pull-outs along Montana State Route 895. The campground and picnic area on the north shore of the lake are popular in the summer, drawing locals and tourists to the area.

IN ORDER to complete the repairs, the reservoir would need to be drained at least to the level of the outlet pipe on the primary drain beginning in this spring.

While Davies’ letter notes “some water would remain in the lake,” he added the agency “cannot determine” how deep or large the remaining water body will be.

But Flathead National Forest spokeswoman Tami MacKenzie said in an email Wednesday officials estimate the lake’s water volume will be reduced by as much as 45%.

The lake will remain partially drained until October, at which time the Forest Service will start refilling the lake. Officials are not sure how long that process will take, but they believe normal lake levels could be achieved by the summer 2022 season.

As it stands, the project is moving forward without an environmental assessment or environmental impact statement — two documents that detail any environmental consequences that may be associated with a plan, policy or project.

Davies’ letter explains he has “made a preliminary determination” that the proposal falls within a category of action that excludes it from requiring such documentation. To support this, he points to a section of the Forest Service National Environmental Policy Act Handbook.

The snippet states an action may qualify for categorical exclusion when the removal, replacement or modification of water control structures such as dams, culverts and levees is needed in order to restore various wetlands, streams and water bodies and allow waters to flow into their natural channels and floodplains.

One example of an exclusion is “repairing an existing water control structure that is no longer functioning properly with minimal dredging excavation, or placement of fill, and does not involve releasing hazardous substances.”

MacKenzie emphasized a final determination has not been made on whether to use a categorical exclusion and added that an environmental analysis could be documented in a decision memorandum instead.

Questions regarding the project may be submitted to Project Leader Jennifer Brady at 406-758-5210 or jennifer.brady@usda.gov and electronic comments may be submitted to comments-northern-flathead-hungry-horse-glacier-view@usda.gov with the project name “Lion Lake Dam Repair” in the subject line. The public has until April 7 to submit their comments.