On our recent trip to Oregon, we spent some time along the Columbia River, the grand waterway of the Pacific Northwest. Rising in southeast British Columbia, it makes a curve to the north and then heads south, picking up flow from the Kootenay and Pend Oreille Rivers before entering the U.S. In eastern Washington, it is joined by the Spokane, Snake and Yakima Rivers and then heads westward along the Oregon border, taking in flow from the John Day, Deschutes, Williamette, Lewis and Cowlitz Rivers before entering the Pacific west of Astoria. Completing a journey of 1245 miles and collecting flow from a watershed of 258,000 square miles, the Columbia is the fourth largest river in the country and the largest west of the Continental Divide.
The current course of the Columbia has been molded since the rise of the Rocky Mountains, 65 million years ago. Once inundated by shallow seas, the region has experienced periodic volcanism over the past 40 million years and Pleistocene floods eroded the landscape 12-20 thousand years ago; the latter carved the famous Channeled Scablands of eastern Washington. Today, erosion continues, fed by heavy snows across the Rockies and Cascades, and, as many of us witnessed in 1980, regional volcanism continues to sculpt this rugged terrain.
Though beautiful and powerful, the Columbia has been used and abused by those who have settled across its vast watershed. Fourteen dams disrupt its flow, providing hydroelectric power, flood control and water for consumption and irrigation; however, these same structures have had a significant impact on the welfare of salmon populations, a threat only partially mitigated by the construction of "fish ladders." In addition, channelization of the river has augmented industrial development throughout its valley, offering a vital route of transportation; of course, this has resulted in significant water pollution, including material from nuclear plants. As is common across the globe, any attempt to balance conservation and resource exploitation tends to tip against the natural environment.
