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State to address erosion at Somers beach

| January 13, 2022 12:00 AM

Montana Fish, Wildlife and Parks is looking to curb erosion on the north shore of Flathead Lake at a new public park in Somers.

The proposal is out for public comment until Jan. 24, and includes structures installed at other eroding sites along the lakeshore, including the state’s Osprey View Wildlife Habitat Protection Area a few miles to the east.

The project is designed to stop erosion and collect sediments and coarse woody debris without isolating the adjacent wetlands. It also intends to minimize impacts to the shoreline from recreational use at a new 106-acre state park in Somers, which was acquired by Fish, Wildlife and Parks in October.

The project would require 3,785 cubic yards of gravel fill, logs with attached root wads, and the construction of an access road to the lakeshore. The temporary road constructed of logs and gravel would be built from an agricultural field to the shoreline. Access to the construction site on the west side of the park would be via Burnell Avenue.

The project is estimated to cost around $564,950.

THE ENVIRONMENTAL Assessment study for the proposal notes the project would treat five sections of eroding beach shorelines at Somers Beach State Park by creating gravel beaches, spit embayments and other common tactics used to curb erosion.

The proposed project area extends from the east side of Somers to the western boundary of the U.S. Fish and Wildlife Waterfowl Production Area. BNSF Railway owns a 15-acre property in this stretch of land that has been stabilized with riprap and would not be included in the project.

Section one encompasses the shoreline that forms the western-most edge of the proposed area and is separated by shoreline from the rest of the project. The EA study said this section would have a mix of larger gravel and cobble used to form this portion of beach. The material would be placed against the existing shoreline with a spit on the northeast end, which would curve out into the lake. The spit embayment would trap gravel and organic material and keep it from moving along the shoreline, much of which is already covered with riprap.

The gravel beach for sections two through five would be constructed with a screened pit run material resulting in a mixture composed predominantly of gravel and sand. This material would be placed against and aligned with the shoreline. Stumps with root wads and attached stems would be placed along the spit end within the embayment of section two and at the tip of the depositional horn of section three.

Waves would wrap around the spit and into the cuspate embayment before breaking on the gravel beach. These waves would carry wood and other organic debris into the cuspate embayment.

The embayment of section two behind the spit would collect fine sediment, wood debris, and organic material. Over time this would allow aquatic and emergent marsh vegetation to colonize the newly formed beach. This process would continue filling the embayment behind the spit creating a hotspot of biological diversity in an area that is currently a concern for accelerated erosion.

Section three of the project has a depositional horn currently being formed by waves; Montana FWP wants to enhance this natural formation by bringing in 550 cubic yards of pit run sand and gravel— as well as root-wads and logs. The shape would enhance the circulation patterns and the low elevation would allow spilling breaking waves to form rather than plunging breaking waves.

Sections four and five would be created by placing 750 and 403 cubic yards respectively of screened 2-inch minus pit run material. Section five would be aligned as a parabolic shaped beach. The landscape would be composed of complex curved shorelines rather than conventional riprap.

MONTANA FWP said their EA found negative impacts from the project would be minimal and primarily associated with construction activities, such as increased turbidity as the lake level rises in the spring. Officials said there remains a very low risk of disturbing contaminated soils near the BNSF property.

The project design and permitting has been completed for the previous owner but no groundwork has begun. Permitting for Montana FWP, as the new owner, is currently being led by Dr. Mark Lorang at Freshwater Map. Project approval and materials preparation is anticipated in February 2022.

The proposal is out for public comment through Jan. 24. Details of the proposal are outlined in a draft environmental assessment published online at https://fwp.mt.gov/news/public-notices. Copies of the EA are also available for public review at FWP Region 1 headquarters in Kalispell. Comments can be mailed to SBSP Erosion Control EA, Montana Fish, Wildlife & Parks, 490 N. Meridian Road, Kalispell, MT 59901, or sent by e-mail to Stevie Burton at Stevie.Burton@mt.gov. A virtual public information meeting will be held Jan. 18 at 6 p.m. The meeting information will be posted online at https://fwp.mt.gov/aboutfwp/regions/region1.

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