LAKE BONNEVILLE – THE FALL FROM THE PROVO LEVEL – A CAUTIONARY TALE

While the Bonneville Flood is the best known and most studied event in the life of Lake Bonneville, a far more significant and troubling event in the timeline was the precipitous fall from the Provo level to the Great Salt Lake level. For at least 40 ky, Lake Bonneville had been rising or overflowing. Suddenly around 15.6 kya, the lake started dropping. It dropped 160m in less than 1 ky. Then the fall abruptly stopped, and, with the exception of the Younger Dryas, the lake level has been relatively stable for the last 15 ky. If that doesn’t trouble you, it should.

Previous work on the subject has left us with the ‘Provo Level Controversy’. Researchers have been unable to agree on the duration of the Provo level or whether there were one or two levels, an earlier and a lower later one, or possibly a series of rising levels.

This poster presents the Bear River Exclusion Theory. This new theory resolves the controversy and fits all the available data. This is very much a cautionary tale since it has a direct parallel with current day activities and the fall of the Great Salt Lake.