Lake Chelan, Washington: Bottom and Sub-Bottom Topography

Lake Chelan, a fjordike lake in north-central Washington, consists of two basins separated by a shallow constriction. The Lucerne Basin, at the upstream end of the lake, is 466 m deep and sediments in it are relatively thin except near the upper end. The Wapato Basin is shallow, but sediments are at least 178 m thick. Both Basins probably had a glacial origin; however, they probably were carved by different glaciers of different ages. The thick sediment in Wapato Basin was probably deposited by meltwater from the Chelan glacier (which occupied Lucerne Basin) and the Okanogan glacier, which blocked the downstream end of Wapato Basin.