Above the John Day Dam, Columbia River
Our trip on the Columbia River began yesterday in Portland on a beautiful clear Pacific Northwest fall afternoon … an auspicious beginning to our voyage In the Wake of Lewis and Clark. During the evening we crossed through the Cascade Range, and in the morning we could look back on this scene to reflect upon landscape-forming processes, past and recent. To the right, on the Washington side of the Columbia River, are the dark bands of the Columbia River basalt flows. They were mostly deposited in a series of lava flows between 17 and 15 million years ago (as explained by Expedition Geologist Marv Beeson.) In the background: Oregon’s characteristic landmark, Mount Hood. It is a composite volcanic cone that formed within the last million years as the Juan de Fuca Plate was subducting beneath the North American Plate. And, spanning the Columbia River to link Washington and Oregon is the John Day Dam, finished in 1968, the most recent of the four dams that tame the lower Columbia River, producing hydroelectric power, water for irrigation, and problems for Pacific salmon. It is a landscape-altering process of a more recent vintage.
Our trip on the Columbia River began yesterday in Portland on a beautiful clear Pacific Northwest fall afternoon … an auspicious beginning to our voyage In the Wake of Lewis and Clark. During the evening we crossed through the Cascade Range, and in the morning we could look back on this scene to reflect upon landscape-forming processes, past and recent. To the right, on the Washington side of the Columbia River, are the dark bands of the Columbia River basalt flows. They were mostly deposited in a series of lava flows between 17 and 15 million years ago (as explained by Expedition Geologist Marv Beeson.) In the background: Oregon’s characteristic landmark, Mount Hood. It is a composite volcanic cone that formed within the last million years as the Juan de Fuca Plate was subducting beneath the North American Plate. And, spanning the Columbia River to link Washington and Oregon is the John Day Dam, finished in 1968, the most recent of the four dams that tame the lower Columbia River, producing hydroelectric power, water for irrigation, and problems for Pacific salmon. It is a landscape-altering process of a more recent vintage.
