Investing in our future: FLBS implements new erosion control beach
New beach to help restore Flathead Lake Shoreline
News from the Flathead Lake Biological Station
For nearly a century, since the regulation of lake levels began, significant shoreline erosion has been documented around Flathead Lake, including at the Bio Station and Flathead Lake State Park - Yellow Bay. In total, the Bio Station’s nearly 7,000 feet of shoreline has suffered significant erosion, and FLBS has lost over 2.9 acres of property, mostly gravel beaches and back shore habitat due to wave action between 1991 and 2006.
To address this erosion, the Bio Station was able to launch a new and exciting project in March 2020. Created by former FLBS research faculty Dr. Mark Lorang, the Erosion Control Beach Project utilized a ‘design-with-nature’ approach to construct a gravel beach that will protect the shoreline while providing environmental and recreational benefits around Flathead Lake for generations to come.
His research led him to design soft structure beaches made of varying particle sizes (i.e., gravel and cobble) that can absorb and dissipate incoming wave energy, thus preventing damaging erosion.
The Bio Station beach is made up of varying sizes of rocks that were placed strategically at low water. First a mix of larger cobbles and gravel was placed lower down on the exposed shoreline. That was followed by a smaller cobble mix above the previous layer. And finally, on top of all that a large amount of pea-sized gravel was deposited extending up towards the trees. When the lake’s water levels were brought up in June, only the easy to walk on smaller gravel was left exposed.
When waves break on the gravel it is pushed around as it absorbs the energy. A big storm at a high water level will create a berm or beach crest that is built up by the largest waves tossing larger rocks on top of the smaller gravels. The waves dynamically reshape the gravels into a beach that can break the waves and dissipate the erosive energy.