Shoreline Fluctuations

Wes Thompson, BioWest geologist

“Wave & particle physics: There is shoreline movement of sand both onshore and out into the lake. This movement has both in-out and lateral components due to long-shore drift. Most sands entered Bear Lake about 18,000 years ago. Ice plays a big part in building winter sand berms

Vegetation also can trap sand & sediment offshore. Jetties and harbors influence sand deposition by interrupting the wind, waves, and

currents. Aerial photograph comparisons show that fine particles & muck will deposit on the leeward side, preventing sand movement along the shoreline.

The effects of gravity on sand deposition get an extra boost each time the lake is drawn down, thereby trapping the sand in deeper water. When the lake rises quickly, some sand is left behind and not affected by the waves for long enough to move it shoreward. This sand is a “lost” resource unless we can physically move it shoreward again. Our sand budget is static.

Over the years, a black “muck” has arrived along the lake’s shores. The plant material that washes up is a combination of organic matter from the Bear River and probably upland plants that have grown on the exposed shoreline. When the lake comes up, the plants die and decay.”

Unless changes are made, these issues will continue to increase and alter the natural shoreline of the lake, which has existed for thousands of years.