Rivers in the Pacific Northwest
The Pacific Northwest is a region that is inextricably linked to its rivers. Most of Washington, Idaho, Oregon and western Montana are part of the Columbia River Basin, and every small creek and stream eventually joins the Columbia or one of its large tributaries. After winding its way across southern Idaho and north through Hells Canyon, the Snake River is the largest tributary to the Columbia, and plays a critical role in Idaho's economy for essentially its entire length.
Let's look at how the primary rivers within the Columbia Basin, as well as the Columbia itself, both shaped the landscape that we see today and play vital roles in the regions history and economy.
FORMATION
The rivers that ultimately drain the Columbia River basin formed over millions of years as both the Rocky and Cascade Mountains formed. The increasing height of the mountain ranges provided both a barrier to the storm systems carrying moisture onshore from the Pacific Ocean and an increasing elevation gradient for the rain and snow to flow down back towards the ocean. As the amount of water falling onto the landscape and the pull of gravity increased over time, the amount of energy associated with these rivers increased, allowing them to cut through and carry impressive amount of material. This type of process produces V-shaped valleys and canyons. An example of this slow and steady erosion is the Salmon River upstream of its confluence with the Little Salmon outside of Riggins, ID.
The rivers that ultimately drain the Columbia River basin formed over millions of years as both the Rocky and Cascade Mountains formed. The increasing height of the mountain ranges provided both a barrier to the storm systems carrying moisture onshore from the Pacific Ocean and an increasing elevation gradient for the rain and snow to flow down back towards the ocean. As the amount of water falling onto the landscape and the pull of gravity increased over time, the amount of energy associated with these rivers increased, allowing them to cut through and carry impressive amount of material. This type of process produces V-shaped valleys and canyons. An example of this slow and steady erosion is the Salmon River upstream of its confluence with the Little Salmon outside of Riggins, ID.
While these erosion and deposition processes happen relatively slowly over eons, a series of rapid, catastrophic events had a much greater impact on the Columbia River basin of eastern Washington, producing the landscape we see today. These events, known as the Ice Age floods, unleashed a torrent of water that drained an ancient lake the size of modern-day Lake Huron in less than a day. This flood event scoured out coulees from the underlying basalt across the inland northwest, creating high-relief features such as the cliffs along Banks Lake and Palouse Falls.
RIVERS AND THE ECONOMY
Consistent with other large rivers around the world, the Columbia River and its tributaries form the backbone of the regional economy. The state of Idaho is entirely dependent on the Snake River economically, and the political history of the state reflects this dependence upon the physical geography. How are we so dependent upon a river system?
1) The large hydroelectric dams (9 on the main stem Columbia and 4 on the lower Snake River in Washington) provide the cheapest, most reliable electricity in the US. This incredible abundance of electricity has lured industries that require large amounts of power to the region for decades.
2) In backing up the rivers behind them, the dams also provide the means to irrigate millions of acres of farmland in Washington and Idaho that would otherwise be too dry for agriculture, such as in the Pocatello region of southeastern Idaho.
3) The rivers provide a means of cheaply exporting all of the grains grown in the Palouse and timber felled from Idaho forests by barge. Lewiston, Idaho, is one of the highest elevation ocean ports in the world at 745 ft, and the furthest inland port on the Pacific coast.
4) The rivers and their tributaries also form the backbone of the Idaho tourism industry. Unlike states with large, culturally-diverse cities, theme parks, or sandy beaches, Idaho tourism is built around its wildnerness experience. Tourists come from around the world (and just across state boundaries) to fish pristine rivers for world-class salmon and trout, or to float down some of the wildest white water in America. For locals, the cool waters that back up as reservoirs behind dams large and small simply spell relief from the heat during the hot Idaho summers.
Consistent with other large rivers around the world, the Columbia River and its tributaries form the backbone of the regional economy. The state of Idaho is entirely dependent on the Snake River economically, and the political history of the state reflects this dependence upon the physical geography. How are we so dependent upon a river system?
1) The large hydroelectric dams (9 on the main stem Columbia and 4 on the lower Snake River in Washington) provide the cheapest, most reliable electricity in the US. This incredible abundance of electricity has lured industries that require large amounts of power to the region for decades.
2) In backing up the rivers behind them, the dams also provide the means to irrigate millions of acres of farmland in Washington and Idaho that would otherwise be too dry for agriculture, such as in the Pocatello region of southeastern Idaho.
3) The rivers provide a means of cheaply exporting all of the grains grown in the Palouse and timber felled from Idaho forests by barge. Lewiston, Idaho, is one of the highest elevation ocean ports in the world at 745 ft, and the furthest inland port on the Pacific coast.
4) The rivers and their tributaries also form the backbone of the Idaho tourism industry. Unlike states with large, culturally-diverse cities, theme parks, or sandy beaches, Idaho tourism is built around its wildnerness experience. Tourists come from around the world (and just across state boundaries) to fish pristine rivers for world-class salmon and trout, or to float down some of the wildest white water in America. For locals, the cool waters that back up as reservoirs behind dams large and small simply spell relief from the heat during the hot Idaho summers.