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Clear Lake is a natural freshwater lake in Lake County, California and is fed by runoff flowing into many streams as well as springs in Soda Bay. Its sole outlet is Cache Creek. In 1914, Cache Creek Dam was constructed at this point in order to increase the lake's capacity and to regulate its outflow. ==Background== Clear Lake is by at its widest point, with surface area of and a capacity. Average depth is , maximum is , lake elevation is , average water temp is in winter and in summer. Clear Lake is believed to be one of the oldest lakes in North America, due to a geological fluke. The lake sits on a huge block of stone which slowly tilts in the northern direction at the same rate as the lake fills in with sediment, thus keeping the water at roughly the same depth. Core samples of the lake's sediments, taken by U.S. Geological Survey geologists in 1973 and 1980, indicate that the lake is at least 480,000 years old. Some experts feel that Mono Lake, to the east of the Sierra Nevada in California, is older than Clear Lake. However, the sedimentary history of Clear Lake is unbroken, while Mono Lake's sediments have been disturbed by past eruptions of the Long Valley Caldera and associated volcanoes. The geology of Clear Lake is chaotic, with numerous small faults being present in the south end of the lake as well as many volcanoes, ranging in age from 10,000 to 2.1 million years, the largest being Mount Konocti, sitting at the middle of the lake's south shore. Clear Lake is sometimes described as the largest natural lake wholly within California. Two lakes are larger: Lake Tahoe is partially in Nevada, and Salton Sea was accidentally flooded. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clear Lake (California)」の詳細全文を読む スポンサード リンク
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