Modern and Glacial-Holocene Carbonate Sedimentation in Bear Lake, Utah-Idaho.

摘要

The Bear Lake Valley in northeastern Utah and adjacent Idaho is a half graben containing a mesosaline-alkaline lake (Bear Lake). The lake is 32 km long and 613 km wide with an area of 280 km2 at full capacity. Maximum depth is 63 m, with a mean depth of 28 m. The present elevation of the lake is 1805 meters above sea level (masl), but this level has varied considerably through time. The natural watershed of the lake is relatively small, with a basin-area:lake-area ratio of only 4.8:1. Historically, the Bear River did not flow into Bear Lake. A series of canals, built from 1909 to 1918, now diverts the Bear River into Bear Lake creating a reservoir to supply irrigation water downstream. This increased the basin-area:lake-area ratio considerably to 29.5:1. The mean annual surface hydrologic flux (including precipitation) to the lake is 0.48 X 109 m3/yr (Lamarra and others, 1986), which is only about 6 percent of the lake volume (7.86 X 109 m3), giving an average residence time of about 16 years. The magnitude of ground water influx is not known.