Snake River

The Snake River is a massive river in the interior Pacific Northwest of the United States.

It is the largest tributary of the Columbia River. A tributary is a river that flows into a larger one. The Snake River is the twelfth largest river in the United States. It contributes about one-fifth of the total water that the Columbia River carries to the Pacific Ocean. This river is a vital part of the regional landscape and watershed.

Its watershed drains parts of six different U.S. states.

The river's path begins in the Rocky Mountains of western Wyoming. It starts north of Two Ocean Pass near the southern border of Yellowstone National Park.

From the mountains, it flows through the Teton Wilderness and meets the Lewis River. It then enters Jackson Lake in Grand Teton National Park. The river meanders through the alpine valley of Jackson Hole. After passing the town of Jackson, it forms the Snake River Canyon of Wyoming. It eventually crosses into Idaho and travels across the arid Snake River Plain.

Geological forces have shaped the river over millions of years. Long ago, volcanic activity covered much of the western watershed with Columbia River basalts.

The Snake River Plain itself was created by the Yellowstone volcanic hotspot. During the most recent Ice Age, catastrophic flooding also altered the landscape. These massive floods helped create features like the Snake River Canyon and Shoshone Falls.

The river's course is also influenced by the Eastern Snake River Plain Aquifer. This is one of the largest groundwater reserves in the United States. It is located in porous volcanic rock beneath the plain. The aquifer absorbs river water and releases it later as springs in the Snake River Canyon.

Human history along the river is long and complex. For thousands of years, indigenous peoples relied on the river for food. The Shoshone and Nez Perce were two of the largest tribes living there.

Salmon fishing played a central role in their culture and diet. In 1805, Lewis and Clark became the first non-natives to see the river. Later, fur trappers explored the watershed and drove beaver populations toward near extinction. During the 1860s, gold discoveries brought a flood of settlers to the region. This led to military conflicts and the eventual expulsion of tribes to reservations.

In the 20th century, humans changed the river through engineering. Large irrigation projects were developed to turn the desert into farmland. This transformed south-central Idaho into a region known as the "Magic Valley."

Many hydroelectric dams were also built to generate electricity. Four navigation dams on the lower section created a shipping channel. This allows heavy barges to travel to Lewiston, Idaho.

Lewiston is now the furthest inland seaport on the West Coast.

The river is famous for its dramatic scenery and deep canyons. Hells Canyon is one of the deepest canyons in North America. It is almost one-third deeper than the Grand Canyon.

The canyon sits between the Rocky Mountains and the Blue Mountains. Within this canyon, the river flows through the Hells Canyon Wilderness. Many parts of the river corridor are only reachable by boat. The water features many Class III and IV rapids.

People visit the area for whitewater boating, fishing, and backpacking.

Nature and policy are closely linked on the Snake River today. The river and its tributary, the Salmon River, host the world's longest sockeye salmon run. These fish swim from the Pacific Ocean all the way to Redfish Lake in Idaho.

However, dam construction and commercial fishing have greatly reduced fish populations. Since the 1950s, agencies and tribal governments have invested in fishery restoration.

There is currently a significant policy debate regarding the removal of the four lower Snake River dams. This debate focuses on improving fish passage for migrating species.