Pacific Northwest
The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...
region in the United States. At long, it is the largest
tributary
A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...
of the
Columbia River
The Columbia River (Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, C ...
, in turn, the largest North American river that empties into the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
. The Snake River rises in western
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...
, then flows through the
Snake River Plain
image:Snake River view near Twin Falls, Idaho.jpg, The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges, gorges, such as this one near Twin Falls, Idaho
The Snake River Plain is a geology, geologic feature ...
of southern
Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...
, the rugged
Hells Canyon
Hells Canyon is a canyon in the Western United States, located along the border of eastern Oregon, a small section of eastern Washington and western Idaho. It is part of the Hells Canyon National Recreation Area which is also located in p ...
on the
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
–Idaho border and the rolling
Palouse Hills
The Palouse ( ) is a distinct geographic region of the northwestern United States, encompassing parts of north central Idaho, southeastern Washington, and, by some definitions, parts of northeast Oregon. It is a major agricultural area, primari ...
of
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
, emptying into the Columbia River at the Tri-Cities in the Columbia Basin of Eastern Washington.
The Snake River
drainage basin
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, t ...
encompasses parts of six
U.S. state
In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...
s (Idaho, Washington, Oregon, Utah, Nevada, and Wyoming) and is known for its varied geologic history. The Snake River Plain was created by a volcanic hotspot which now lies underneath the Snake River headwaters in
Yellowstone National Park
Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress with the Yellowston ...
. Gigantic glacial-retreat flooding episodes during the previous
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...
carved out canyons, cliffs, and waterfalls along the middle and lower Snake River. Two of these catastrophic flooding events, the
Missoula Floods
The Missoula floods (also known as the Spokane floods or the Bretz floods or Bretz's floods) were cataclysmic glacial lake outburst floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ...
and
Bonneville Flood
The Bonneville flood was a catastrophic flooding event in the last ice age, which involved massive amounts of water inundating parts of southern Idaho and eastern Washington along the course of the Snake River. Unlike the Missoula Floods, whic ...
, significantly affected the river and its surroundings.
Native Americans have lived along the Snake for more than 11,000 years.
Salmon
Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...
from the Pacific Ocean spawned by the millions in the river and were a vital resource for people living on the Snake downstream of
Shoshone Falls
Shoshone Falls () is a waterfall in the western United States, on the Snake River in south-central Idaho, approximately northeast of the city of Twin Falls. Sometimes called the "Niagara of the West," Shoshone Falls is in height, higher than ...
. By the time
Lewis and Clark
Lewis may refer to:
Names
* Lewis (given name), including a list of people with the given name
* Lewis (surname), including a list of people with the surname
Music
* Lewis (musician), Canadian singer
* "Lewis (Mistreated)", a song by Radiohead ...
explored the area, the
Nez Perce
The Nez Percé (; autonym in Nez Perce language: , meaning "we, the people") are an Indigenous people of the Plateau who are presumed to have lived on the Columbia River Plateau in the Pacific Northwest region for at least 11,500 years.Ames, K ...
and
Shoshone
The Shoshone or Shoshoni ( or ) are a Native American tribe with four large cultural/linguistic divisions:
* Eastern Shoshone: Wyoming
* Northern Shoshone: southern Idaho
* Western Shoshone: Nevada, northern Utah
* Goshute: western Utah, easter ...
were the dominant Native American groups in the region. Later explorers and fur trappers further changed and used the resources of the Snake River basin. At one point, the sign language used by the Shoshones representing weaving baskets was misinterpreted to represent a snake, giving the Snake River its name.
By the middle 19th century, the
Oregon Trail
The Oregon Trail was a east–west, large-wheeled wagon route and Westward Expansion Trails, emigrant trail in the United States that connected the Missouri River to valleys in Oregon. The eastern part of the Oregon Trail spanned part of what ...
had become well established, bringing numerous settlers to the Snake River region.
Steamboat
A steamboat is a boat that is marine propulsion, propelled primarily by marine steam engine, steam power, typically driving propellers or Paddle steamer, paddlewheels. Steamboats sometimes use the ship prefix, prefix designation SS, S.S. or S/S ...
s and railroads moved agricultural products and minerals along the river throughout the 19th and early 20th centuries. Starting in the 1890s, fifteen major dams were built on the Snake River to generate
hydroelectricity
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other Renewabl ...
, enhance navigation, and provide irrigation water. However, these dams blocked salmon migration above Hells Canyon and have led to water quality and environmental issues in certain parts of the river. The removal of several dams on the lower Snake River has been proposed in order to restore some of the river's once-tremendous salmon runs.
Course
Formed by the confluence of three tiny streams on the southwest flank of Two Oceans Plateau in
Yellowstone National Park
Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress with the Yellowston ...
, western
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...
, the Snake starts out flowing west and south into Jackson Lake. Its first run through
Jackson Hole
Jackson Hole (originally called Jackson's Hole by mountain men) is a valley between the Gros Ventre and Teton mountain ranges in the U.S. state of Wyoming, near the border with Idaho, in Teton County, one of the richest counties in the Unite ...
, a wide valley between the
Teton Range
The Teton Range is a mountain range of the Rocky Mountains in North America. It extends for approximately in a north–south direction through the U.S. state of Wyoming, east of the Idaho state line. It is south of Yellowstone National Park and ...
and the
Gros Ventre Range
The Gros Ventre Range ( ) is part of the Central Rocky Mountains and is located west of the Continental Divide in U.S. state of Wyoming. The highest summit in the range is Doubletop Peak at . The Gros Ventre Range is mostly within the Gros Ven ...
. Below the tourist town of
Jackson
Jackson may refer to:
People and fictional characters
* Jackson (name), including a list of people and fictional characters with the surname or given name
Places
Australia
* Jackson, Queensland, a town in the Maranoa Region
* Jackson North, Qu ...
Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...
Greys River
The Greys River is a tributary of the Snake River, flowing through western Wyoming in the United States. The river is about long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed May 4 ...
s before entering Palisades Reservoir, where the Salt River joins at the mouth of Star Valley. Below
Palisades Dam
Palisades Dam () is an earth-fill dam in the western United States, on the upper Snake River in eastern Idaho. Located in Bonneville County near the Wyoming border, the dam was completed in 1957.
Providing irrigation water, flood control, a ...
, the Snake River flows through the
Snake River Plain
image:Snake River view near Twin Falls, Idaho.jpg, The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges, gorges, such as this one near Twin Falls, Idaho
The Snake River Plain is a geology, geologic feature ...
, a vast arid
physiographic province
physiographic province is a geographic region with a characteristic geomorphology, and often specific subsurface rock type or structural elements. The continents are subdivided into various physiographic provinces, each having a specific characte ...
extending through southern Idaho southwest of the Rocky Mountains and underlain by the Snake River Aquifer, one of the most productive aquifers in the United States.
Southwest of
Rexburg, Idaho
Rexburg is a city in Madison County, Idaho, United States. The population was 39,409 at the 2020 census. The city is the county seat of Madison County and its largest city. Rexburg is the principal city of the Rexburg, ID Micropolitan Statist ...
, the Snake is joined from the north by Henrys Fork. The Henrys Fork is sometimes called the North Fork of the Snake River, with the main Snake above their confluence known as the "South Fork". From there, it turns south, flowing through downtown
Idaho Falls
Idaho Falls (Shoshoni language, Shoshoni: Dembimbosaage) is a city in and the county seat of Bonneville County, Idaho, Bonneville County, Idaho, United States. It is the state's largest city outside the Boise metropolitan area. As of the 2020 Un ...
, then past the
Fort Hall Indian Reservation
The Fort Hall Reservation is a Native American reservation of the federally recognized Shoshone-Bannock Tribes (Shoshoni language: Pohoko’ikkateeCrum, B., Crum, E., & Dayley, J. P. (2001). Newe Hupia: Shoshoni Poetry Songs. University Press ...
and into
American Falls Reservoir
The American Falls Dam is a concrete gravity-type dam located near the town of American Falls, Idaho, on river mile 714.7 of the Snake River. The dam and reservoir are a part of the Minidoka Project on the Snake River Plain and are used primari ...
, where it is joined by the Portneuf River. The Portneuf River Valley is an overflow channel that in the last glacial period carried floodwaters from pluvial
Lake Bonneville
Lake Bonneville was the largest Late Pleistocene paleolake in the Great Basin of western North America. It was a pluvial lake that formed in response to an increase in precipitation and a decrease in evaporation as a result of cooler temperature ...
into the Snake River, significantly altering the landscape of the Snake River Plain through massive erosion. From there, the Snake resumes its journey west, entering the Snake River Canyon of Idaho. It is interrupted by several major cataracts, the largest being
Shoshone Falls
Shoshone Falls () is a waterfall in the western United States, on the Snake River in south-central Idaho, approximately northeast of the city of Twin Falls. Sometimes called the "Niagara of the West," Shoshone Falls is in height, higher than ...
, which historically marked the upriver limit of migrating
salmon
Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...
. A short distance downstream it passes under the
Perrine Bridge
The I. B. Perrine Bridge is a four-lane truss arch span in the western United States. Located at Twin Falls, Idaho, it carries U.S. Highway 93 over the Snake River Canyon, connecting to Jerome County and Interstate 84.
The Perrine Bridge i ...
. Near Twin Falls, the Snake approaches the southernmost point in its entire course, after which it starts to flow west-northwest.
The Snake continues through its canyon, receiving the Malad River from the east near
Bliss
BLISS is a system programming language developed at Carnegie Mellon University (CMU) by W. A. Wulf, D. B. Russell, and A. N. Habermann around 1970. It was perhaps the best known system language until C debuted a few years later. Since then, C b ...
and then the
Bruneau River
The Bruneau River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. tributary of the Snake River, in the U.S. states of Idaho and Nevada. It runs through a narrow canyon cut into ancient lava flows in south ...
from the south in
C.J. Strike Reservoir
C.J. Strike Reservoir is a reservoir located in southwestern Idaho. Its main recreational features include the C. J. Strike Dam and its reservoir, an impoundment of the Snake River and Bruneau River. This in turn provides excellent fishing (both ...
. It passes through an agricultural valley about southwest of
Boise
Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown area' ...
and flows briefly west into
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
, before turning north to define the Idaho–Oregon border. Here the Snake River almost doubles in size as it receives several major tributaries – the Owyhee from the southwest, then the
Boise
Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown area' ...
and Payette rivers from the east, and farther downstream the
Malheur River
The Malheur River (local pronunciation: "MAL-hyure") is a tributary of the Snake River in eastern Oregon in the United States. It drains a Great Basin Desert, high desert area, between the Harney Basin and the Blue Mountains (Oregon), Blue Moun ...
from the west and
Weiser River
The Weiser River is a tributary of the Snake River in western Idaho in the United States. It drains a mountainous area of consisting primarily of low rolling foothills intersected by small streams south and east of Hells Canyon along the Idaho ...
from the east. North of Boise, the Snake enters
Hells Canyon
Hells Canyon is a canyon in the Western United States, located along the border of eastern Oregon, a small section of eastern Washington and western Idaho. It is part of the Hells Canyon National Recreation Area which is also located in p ...
, a steep, spectacular, rapid-strewn gorge that cuts through the Salmon River Mountains and Blue Mountains of Idaho and Oregon. Hells Canyon is one of the most rugged and treacherous portions of the course of the Snake River, posing a major obstacle for 19th-century American explorers. Here the Snake is also impounded by
Hells Canyon
Hells Canyon is a canyon in the Western United States, located along the border of eastern Oregon, a small section of eastern Washington and western Idaho. It is part of the Hells Canyon National Recreation Area which is also located in p ...
,
Oxbow __NOTOC__
An oxbow is a U-shaped metal pole (or larger wooden frame) that fits the underside and the sides of the neck of an ox or bullock. A bow pin holds it in place.
The term " oxbow" is widely used to refer to a U-shaped meander in a rive ...
, and
Brownlee Dam
Brownlee Dam is a hydroelectric earth fill embankment dam in the western United States, on the Snake River along the Idaho-Oregon border. In Hells Canyon at river mile 285, it impounds the Snake River in the Brownlee Reservoir.
It is part of ...
s, which together make up the Hells Canyon Hydroelectric Project.
At the halfway point in Hells Canyon, in one of the most remote and inaccessible sections of its course, the Snake River is joined from the east by its largest tributary, the Salmon River. From there, the Snake begins to form the
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
–Idaho border, receiving the
Grande Ronde River
The Grande Ronde River ( or, less commonly, ) is a tributary of the Snake River, long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed May 3, 2011 in northeastern Oregon and southeastern ...
from the west before receiving the Clearwater River from the east at Lewiston, which marks the head of navigation on the Snake. The river leaves Hells Canyon and turns west, winding through the
Palouse Hills
The Palouse ( ) is a distinct geographic region of the northwestern United States, encompassing parts of north central Idaho, southeastern Washington, and, by some definitions, parts of northeast Oregon. It is a major agricultural area, primari ...
of
eastern Washington
Eastern Washington is the region of the U.S. state of Washington located east of the Cascade Range. It contains the city of Spokane (the second largest city in the state), the Tri-Cities, the Columbia River and the Grand Coulee Dam, the Hanfor ...
. The Lower Snake River Project's four dams and
navigation lock
A lock is a device used for raising and lowering boats, ships and other watercraft between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water lev ...
s have transformed this part of the Snake River into a series of reservoirs. The confluence of the Snake and Columbia rivers at
Burbank, Washington
Burbank is a census-designated place (CDP) in Walla Walla County, Washington, United States, where the Snake River meets the Columbia. The population was 3,291 at the 2010 census. Named for Luther Burbank, the city is located just east of Pasco ...
is part of
Lake Wallula
Lake Wallula is a reservoir on the Columbia River in the United States, between the U.S. states of Washington (U.S. state), Washington and Oregon. It was created in 1954 with the construction of McNary Dam. It reaches from McNary Dam near the city ...
, the reservoir of McNary Dam. The Columbia River flows about farther west to the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
near
Astoria, Oregon
Astoria is a port city and the seat of Clatsop County, Oregon, United States. Founded in 1811, Astoria is the oldest city in the state and was the first permanent American settlement west of the Rocky Mountains. The county is the northwest corne ...
.
Geology
Most of western North America was drowned by shallow seas off and on from around 800–200 million years ago. This was the accumulation phase of the mountain building cycle, where mostly sedimentary rocks accumulate as the seafloor subsides. The western edge of North America was a passive continental margin and therefore was not near a plate boundary. 180 million years ago, the tectonic setting of western North America changed to an active continental margin, and a convergent plate boundary formed, which crumpled the deposits from the accumulation phase into fold-thrust mountain ranges. Plate convergence gave rise to the Coastal Ranges and then to the Rocky Mountains due to friction between the
Farallon Plate
The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west c ...
sinking beneath the
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...
. Another tectonic player is the Yellowstone hotspot, which is a large plume of partially molten material lodged in the mantle. As the North American Plate moved west–southwest over the hot spot, massive amounts of basaltic lava were extruded onto the crust. A load of these dense lava flows bent down the crust immediately below it, and the mountains formed earlier to make the WSW-ENE oriented trough known as the Snake River Plain. The river did not carve the Snake River Plain, but rather the Snake River took the course of least resistance and followed the path formed by the hot spot through the Rocky Mountains. The first lava flows started pouring out in what is now the western part of the Snake River Plain and is still extruding in the eastern part of the plain. Even larger lava flows of
Columbia River basalts
The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. The basalt grou ...
issued over eastern Washington, forming the
Columbia Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia ...
southeast of the Columbia River and the Palouse Hills in the lower Snake. Separate volcanic activity formed the northwestern portion of the plain, an area far from the path of the hotspot The hot spot now resides beneath Yellowstone National Park. The heat from the molten rock beneath the park domes the crust up to form the Yellowstone Plateau
The Snake River Plain and the gap between the
Sierra Nevada
The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...
and the Cascade Range together formed a "moisture channel," opening the way for Pacific storms to travel more than inland to the headwaters of the Snake River. When the Teton Range uplifted about 9 million years ago along a
detachment fault
A detachment fault is a gently dipping normal fault associated with large-scale extensional tectonics. Detachment faults often have very large displacements (tens of km) and juxtapose unmetamorphosed hanging walls against medium to high-grade me ...
running north–south through the central Rockies, the river maintained its original course and cut through the southern end of the mountains, forming the Snake River Canyon of Wyoming. About 6 million years ago, the Salmon River Mountains and Blue Mountains at the far end of the plain began to rise; the river cut through these mountains as well, forming Hells Canyon. Lake Idaho, formed during the
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
, covered a large portion of the Snake River Plain between Twin Falls and Hells Canyon, and its
lava dam
A volcanic dam is a type of natural dam produced directly or indirectly by volcanism, which holds or temporarily restricts the flow of surface water in existing streams, like a man-made dam. There are two main types of volcanic dams, those creat ...
was finally breached about 2 million years ago.
Lava flowing from Cedar Butte in present southeast Idaho blocked the Snake River at Eagle Rock about 42,000 years ago, near the present-day site of
American Falls Dam
The American Falls Dam is a concrete gravity-type dam located near the town of American Falls, Idaho, on river mile 714.7 of the Snake River. The dam and reservoir are a part of the Minidoka Project on the Snake River Plain and are used primaril ...
. A lake, known as American Falls Lake, formed behind the barrier. The lake was stable and survived for nearly 30,000 years. About 14,500 years ago,
pluvial
In geology and climatology, a pluvial is either a modern climate characterized by relatively high precipitation or an interval of time of variable length, decades to thousands of years, during which a climate is characterized by relatively high ...
Lake Bonneville in the
Great Salt Lake
The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, particula ...
area, formed in the last glacial period, spilled catastrophically down the Portneuf River into the Snake in an event known as the
Bonneville flood
The Bonneville flood was a catastrophic flooding event in the last ice age, which involved massive amounts of water inundating parts of southern Idaho and eastern Washington along the course of the Snake River. Unlike the Missoula Floods, whic ...
. This was one of the first in a series of catastrophic flooding events in the Northwest known as the Ice Age Floods.
The deluge caused American Falls Lake to breach its natural lava dam, which was rapidly eroded with only the American Falls left in the end. The flood waters of Lake Bonneville, approximately twenty times the flow of the Columbia River or 5 million ft3/s (140,000 m3/s), swept down the Snake River and across the entirety of southern Idaho. For miles on either side of the river, flood waters stripped away soils and scoured the underlying basalt bedrock, transforming the region into
channeled scablands
The Channeled Scablands are a relatively barren and soil-free region of interconnected relict and dry flood channels, coulees and cataracts eroded into Palouse loess and the typically flat-lying basalt flows that remain after cataclysmic floods ...
forming the Snake River Canyon and creating Shoshone Falls, Twin Falls, Crane Falls, Swan Falls and other waterfalls along the Idaho section of the river. The Bonneville flood waters continued through Hells Canyon and eventually reached the Columbia River. The flood widened Hells Canyon but did not deepen it.
As the Bonneville Floods rushed down the Snake River, the
Missoula Floods
The Missoula floods (also known as the Spokane floods or the Bretz floods or Bretz's floods) were cataclysmic glacial lake outburst floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ...
occurred in the same period, but originating farther north. The Missoula Floods, which occurred more than 40 times between 15,000 and 13,000 years ago, were caused by
Glacial Lake Missoula
Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago. The lake measured about and contained about of water, half the volume of Lake Mic ...
on the Clark Fork repeatedly being impounded by ice dams then breaking through, with the lake's water rushing over much of eastern Washington in massive surges far larger than the Lake Bonneville Flood. These floods pooled behind the Cascade Range into enormous lakes and spilled over the northern
drainage divide
A drainage divide, water divide, ridgeline, watershed, water parting or height of land is elevated terrain that separates neighboring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a singl ...
of the Snake River watershed, carving deep canyons through the Palouse Hills including the
Palouse River
The Palouse River is a tributary of the Snake River in Washington (state), Washington and Idaho, in the Northwestern United States, northwest United States. It flows for U.S. Geological Survey. National Hydrography Dataset high-resolution flowline ...
canyon and Palouse Falls. The Lake Bonneville Floods and the Missoula Floods helped widen and deepen the
Columbia River Gorge
The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range, forming the boundary between the sta ...
, a giant
water gap
A water gap is a gap that flowing water has carved through a mountain range or mountain ridge and that still carries water today. Such gaps that no longer carry water currents are called wind gaps. Water gaps and wind gaps often offer a prac ...
which allows water from the Columbia and Snake rivers to take a direct route through the Cascade Range to the Pacific.
The massive amounts of sediment deposited by the Lake Bonneville Floods in the Snake River Plain also had a lasting effect on most of the middle Snake River. The high
hydraulic conductivity
Hydraulic conductivity, symbolically represented as (unit: m/s), is a property of porous materials, soils and rocks, that describes the ease with which a fluid (usually water) can move through the pore space, or fractures network. It depends on th ...
of the mostly-
basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
rocks in the plain led to the formation of the Snake River Aquifer, one of the most productive aquifers in North America. Many rivers and streams flowing from the north side of the plain sink into the aquifer instead of flowing into the Snake River, a group of watersheds called the lost streams of Idaho. The aquifer filled to hold nearly of water, underlying about in a plume thick. In places, water exits from rivers at rates of nearly . Much of the water lost by the Snake River as it transects the plain issues back into the river at its western end, by way of many artesian
spring
Spring(s) may refer to:
Common uses
* Spring (season)
Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...
s.
Watershed
The Snake River is the thirteenth longest river in the United States. Its watershed is the 10th largest among North American rivers, and covers almost in portions of six U.S. states: Wyoming, Idaho,
Nevada
Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
,
Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
, Oregon, and
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
, with the largest portion in Idaho. Most of the Snake River watershed lies between the Rocky Mountains on the east and the Columbia Plateau on the northwest. The largest tributary of the Columbia River, the Snake River watershed makes up about 41% of the entire Columbia River Basin. Its average discharge at the mouth constitutes 31% of the Columbia's flow at that point. Above the confluence, the Snake is slightly longer than the Columbia— compared to —and its drainage basin is slightly larger—4% bigger than the upstream Columbia River watershed.
The mostly
semi-arid
A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-ar ...
, even
desert
A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
climate of the Snake River watershed on average, receives less than of
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
per year. However, precipitation in the Snake River watershed varies widely. At Twin Falls, in the center of the Snake River Plain, the climate is nearly desert, with an annual rainfall of just , although the average snowfall is . This desert climate occupies the majority of the basin of the Snake River, so although it is longer than the Columbia River above the Tri-Cities, its average discharge is significantly less. However, in the high Rockies of Wyoming, in the upper Jackson Hole area, the average precipitation is over , and snowfall averages . Most of the Snake River basin consists of wide, arid plains and rolling hills, bordered by high mountains. In the upper parts of the watershed, however, the river flows through an area with a distinct
alpine climate
Alpine climate is the typical weather (climate) for elevations above the tree line, where trees fail to grow due to cold. This climate is also referred to as a mountain climate or highland climate.
Definition
There are multiple definitions of ...
. There are also stretches where the river and its tributaries have incised themselves into tight gorges. The Snake River watershed includes parts of Yellowstone National Park,
Grand Teton National Park
Grand Teton National Park is an American national park in northwestern Wyoming. At approximately , the park includes the major peaks of the Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Grand Teton Na ...
,
Hells Canyon National Recreation Area
Hells Canyon National Recreation Area is a United States national recreation area on the borders of the U.S. states of Oregon and Idaho. Managed by the U.S. Forest Service as part of the Wallowa-Whitman National Forest, the recreation area was es ...
, and many other national and state parks.
Much of the area along the river, within a few miles of its banks, is irrigated farmland, especially in its middle and lower course. Irrigation dams include American Falls Dam,
Minidoka Dam
The Minidoka Dam is an earthfill dam in the western United States, on the Snake River in south central Idaho. Completed in 1906, the dam is east of Rupert on county highway 400; it is high and nearly a mile (1.6 km) in length, with a wide o ...
, and C.J. Strike Dam. Aside from water from the river, water is also pulled from the Snake River Aquifer for irrigation. Major cities along the river include
Jackson
Jackson may refer to:
People and fictional characters
* Jackson (name), including a list of people and fictional characters with the surname or given name
Places
Australia
* Jackson, Queensland, a town in the Maranoa Region
* Jackson North, Qu ...
in Wyoming, Twin Falls,
Idaho Falls
Idaho Falls (Shoshoni language, Shoshoni: Dembimbosaage) is a city in and the county seat of Bonneville County, Idaho, Bonneville County, Idaho, United States. It is the state's largest city outside the Boise metropolitan area. As of the 2020 Un ...
, Boise, and Lewiston in Idaho, and the Tri-Cities in Washington (
Kennewick
Kennewick () is a city in Benton County in the U.S. state of Washington. It is located along the southwest bank of the Columbia River, just southeast of the confluence of the Columbia and Yakima rivers and across from the confluence of the C ...
, Pasco and Richland). There are fifteen dams in total along the Snake River, which aside from irrigation, also produce electricity, maintain a navigation channel along part of the river's route, and provide flood control. However, fish passage is limited to the stretch below Hells Canyon.
The Snake River watershed is bounded by several other major North American watersheds, which drain both to the Atlantic or the Pacific, or into
endorheic
An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...
basins. On the southwest side, a divide separates the Snake watershed from Oregon's
Harney Basin
The Harney Basin is an endorheic basin in southeastern Oregon in the United States at the northwestern corner of the Great Basin. One of the least populated areas of the contiguous United States, it is located largely in northern Harney County, ...
, which is endorheic. On the south, the Snake watershed borders that of the
Humboldt River
The Humboldt River is an extensive river drainage system located in north-central Nevada. It extends in a general east-to-west direction from its headwaters in the Jarbidge, Independence, and Ruby Mountains in Elko County, to its terminus in the ...
in Nevada, and the watershed of the Great Salt Lake (the
Bear
Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Nor ...
,
Jordan
Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...
and Weber rivers) on the south.
The Snake River also shares a boundary with the
Green River Green River may refer to:
Rivers
Canada
* Green River (British Columbia), a tributary of the Lillooet River
*Green River, a tributary of the Saint John River, also known by its French name of Rivière Verte
*Green River (Ontario), a tributary of ...
to the southeast; the Green River drains parts of Wyoming and Utah and is the largest tributary of the
Colorado River
The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of ...
. On the western extremity, for a short stretch, the Continental Divide separates the Snake watershed from the
Bighorn River
The Bighorn River is a tributary of the Yellowstone, approximately long, in the states of Wyoming and Montana in the western United States. The river was named in 1805 by fur trader François Larocque for the bighorn sheep he saw along its ban ...
, a tributary of the
Yellowstone River
The Yellowstone River is a tributary of the Missouri River, approximately long, in the Western United States. Considered the principal tributary of upper Missouri, via its own tributaries it drains an area with headwaters across the mountains an ...
, which the Snake begins near. On the north the Snake River watershed is bounded by the Red Rock River, a tributary of the
Beaverhead River
The Beaverhead River is an approximately tributary of the Jefferson River in southwest Montana (east of the Continental Divide). It drains an area of roughly . The river's original headwaters, formed by the confluence of the Red Rock River and ...
, which flows into the Jefferson River and into the Missouri River, part of the
Gulf of Mexico
The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
drainage basin.
The rest of the Snake River watershed borders on several other major Columbia River tributaries - mostly the
Spokane River
The Spokane River is a tributary of the Columbia River, approximately long, in northern Idaho and eastern Washington in the United States. It drains a low mountainous area east of the Columbia, passing through the Spokane Valley and the city of ...
to the north, but also Clark Fork in
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
to the northeast and the
John Day River
The John Day River is a tributary of the Columbia River, approximately long, in northeastern Oregon in the United States. It is known as the Mah-Hah River by the Cayuse people, the original inhabitants of the region. Undammed along its entire ...
to the west. Of these, the Clark Fork (via the
Pend Oreille River
The Pend Oreille River ( ) is a tributary of the Columbia River, approximately long, in northern Idaho and northeastern Washington in the United States, as well as southeastern British Columbia in Canada. In its passage through British Columbia ...
) and the Spokane join the Columbia above the Snake, while the John Day joins downstream of the Snake, in the Columbia River Gorge. It is of note that the northeastern divide of the Snake River watershed forms the Idaho-Montana boundary, so the Snake River watershed does not extend into Montana.
Mountain ranges in the Snake watershed include the Teton Range,
Bitterroot Range
The Bitterroot Range is a mountain range and a subrange of the Rocky Mountains that runs along the border of Montana and Idaho in the northwestern United States. The range spans an area of and is named after the bitterroot (''Lewisia rediviva' ...
,
Clearwater Mountains
The Clearwater Mountains are part of the Rocky Mountains, located in the panhandle of Idaho in the Western United States. The mountains lie between the Salmon River and the Bitterroot Range and encompass an area of .
__NOTOC__ Subranges North ...
Wind River Range
The Wind River Range (or "Winds" for short) is a mountain range of the Rocky Mountains in western Wyoming in the United States. The range runs roughly NW–SE for approximately . The Continental Divide follows the crest of the range and inclu ...
.
Grand Teton
Grand Teton is the highest mountain in Grand Teton National Park, in Northwest Wyoming, and a classic destination in American mountaineering.
Geography
Grand Teton, at , is the highest point of the Teton Range, and the second highest peak in t ...
is the highest point in the Snake River watershed, reaching in elevation. The elevation of the Snake River is when it joins the Columbia River.
Pollution
Agricultural runoff from farms and
ranch
A ranch (from es, rancho/Mexican Spanish) is an area of land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of a farm. These terms are most often ...
es in the Snake River Plain and many other areas has severely damaged the ecology of the river throughout the 20th century. After the first irrigation dams on the river began operation in the first decade of the 20th century, much of the
arable land
Arable land (from the la, arabilis, "able to be ploughed") is any land capable of being ploughed and used to grow crops.''Oxford English Dictionary'', "arable, ''adj''. and ''n.''" Oxford University Press (Oxford), 2013. Alternatively, for the ...
in a strip a few miles wide along the Snake River was cultivated or turned to
pasture
Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or swine ...
, and agricultural return flows began to pollute the Snake. Runoff from several
feedlot
A feedlot or feed yard is a type of animal feeding operation (AFO) which is used in intensive animal farming, notably beef cattle, but also swine, horses, sheep, turkeys, chickens or ducks, prior to slaughter. Large beef feedlots are called conc ...
s was dumped into the river until laws made the practice illegal.
Fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
,
manure
Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the fertility of soil by adding organic matter and nutri ...
and other chemicals and pollutants washed into the river greatly increase the nutrient load, especially of
phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
,
fecal coliform
A fecal coliform (British: faecal coliform) is a facultatively anaerobic, rod-shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Fecal coliforms are capable of growth ...
s and
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
. During low water,
algae bloom
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in Fresh water, freshwater or Ocean, marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ...
s occur throughout the calm stretches of the river, depleting its oxygen supply.
Much of the return flows do not issue directly back into the Snake River, but rather feed the Snake River Aquifer underneath the Snake River Plain. Water diverted from the river for irrigation, after absorbing any surface pollutants, re-enters the ground and feeds the aquifer. Although the aquifer has maintained its level, it has become increasingly laced with contaminants. Water in the aquifer eventually travels to the west side of the Snake River Plain and re-enters the river as springs. Throughout much of the Snake River Plain and Hells Canyon, excessive sediment is also a recurring problem. In December 2007, the
U.S. Environmental Protection Agency
The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...
(EPA) issued a permit requiring owners of
fish farm
upright=1.3, Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye">mariculture.html" ;"title="Salmon farming in the sea (mariculture">Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye, Scotland
Fish farming or ...
s along the Snake River to reduce their phosphorus discharge by 40%. Pollutant levels in Hells Canyon upstream of the Salmon River confluence, including that of water temperature, dissolved nutrients, and sediment, are required to meet certain levels.
Discharge
The Snake River's average flow is . The
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
recorded the river's discharge from a period of 1963–2000 at a
stream gauge
A stream gauge, streamgage or stream gauging station is a location used by hydrologists or environmental scientists to monitor and test terrestrial bodies of water. Hydrometric measurements of water level surface elevation ("stage") and/or volu ...
below
Ice Harbor Dam
Ice Harbor Lock and Dam is a hydroelectric, concrete gravity Run-of-the-river hydroelectricity, run-of-the-river dam in the Northwestern United States, northwest United States. On the lower Snake River in southeastern Washington (state), Washingto ...
. In that period, the largest average annual flow recorded was in 1997, and the lowest was in 1992. The lowest recorded daily mean flow was on February 4, 1979. On August 27, 1965, there was temporarily no flow as a result of testing at Ice Harbor Dam. The highest recorded flow was on June 19, 1974. The highest flow ever recorded on the Snake River was at a different USGS stream gauge near Clarkston, which operated from 1915 to 1972. This gauge recorded a maximum flow of —more than the Columbia's average discharge—on May 29, 1948. An even larger peak discharge, estimated at , occurred during the flood of June 1894.
The river's flow is also measured at several other points in its course. Above Jackson Lake, Wyoming, the discharge is about from a drainage area of . At
Minidoka, Idaho
Minidoka is a city in Minidoka County, Idaho, United States. The population was 112 at the 2010 census. It is part of the Burley, Idaho Micropolitan Statistical Area.
Today Minidoka is one of Idaho's most strongly Hispanic communities, with o ...
, about halfway through the Snake River Plain, the river's discharge rises to . However, at
Buhl, Idaho
Buhl is a city located on the old Oregon Trail in the western half of Twin Falls County, Idaho. The population was 4,122 at the time of the 2010 census, up from 3,985 in 2000.Weiser at the beginning of Hells Canyon, the Snake's flow rises to after receiving several major tributaries such as the Payette, Owyhee and Malheur. The discharge further increases to at Hells Canyon Dam on the border of Idaho and Oregon. At
Anatone, Washington
Anatone () is an unincorporated area, unincorporated community in the Northwestern United States, northwest United States, located in Asotin County, Washington. Because it is not tracked by the U.S. Census, a Census population estimate is not avai ...
, downstream of the confluence with the Salmon, one of the Snake's largest tributaries, the mean discharge is .
History
Name
The name Snake River comes from the so-called "
Snake Indians
Snake Indians is a collective name given to the Northern Paiute, Bannock (tribe), Bannock, and Shoshone Native Americans in the United States, Native American tribe (Native American), tribes.
The term was used as early as 1739 by French trader an ...
" who lived along the river, actually
Shoshone
The Shoshone or Shoshoni ( or ) are a Native American tribe with four large cultural/linguistic divisions:
* Eastern Shoshone: Wyoming
* Northern Shoshone: southern Idaho
* Western Shoshone: Nevada, northern Utah
* Goshute: western Utah, easter ...
,
Bannock
Bannock may mean:
* Bannock (food), a kind of bread, cooked on a stone or griddle
* Bannock (Indigenous American), various types of bread, usually prepared by pan-frying
* Bannock people, a Native American people of what is now southeastern Oregon ...
, and
Northern Paiute
Northern may refer to the following:
Geography
* North, a point in direction
* Northern Europe, the northern part or region of Europe
* Northern Highland, a region of Wisconsin, United States
* Northern Province, Sri Lanka
* Northern Range, a r ...
. The "Snake Indian" name for those groups came from
Plains Indians
Plains Indians or Indigenous peoples of the Great Plains and Canadian Prairies are the Native American tribes and First Nation band governments who have historically lived on the Interior Plains (the Great Plains and Canadian Prairies) of N ...
—possibly in reference to the use of snake heads in war or because the Plains Indians referred to these groups with a snake-like hand gesture, possibly originally intended to indicate a salmon.
Canadian explorer David Thompson first recorded the Native American name of the Snake River as ''Shawpatin'' when he arrived at its mouth by boat in 1800. When the
Lewis and Clark Expedition
The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select gro ...
crossed westwards into the Snake River watershed in 1805, they first gave it the name ''Lewis River'', ''Lewis Fork'' or ''Lewis's Fork'', as
Meriwether Lewis
Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with ...
was the first of their group to sight the river.
The group also learned that the Native Americans called the river ' or ' (for an herb that grew prolifically along its banks).
Later American explorers, some of whom were originally part of the Lewis and Clark expedition, journeyed into the Snake River watershed and records show a variety of names have been associated with the river. The explorer
Wilson Price Hunt
Wilson Price Hunt (March 20, 1783 – April 13, 1842) was an early pioneer and explorer of the Oregon Country in the Pacific Northwest of North America. Employed as an agent in the fur trade under John Jacob Astor, Hunt organized and led the gre ...
of the
Astor Expedition
The Pacific Fur Company (PFC) was an American fur trade venture wholly owned and funded by John Jacob Astor that functioned from 1810 to 1813. It was based in the Pacific Northwest, an area contested over the decades between the United Kingdom o ...
named the river as ''Mad River''. Others gave the river names including ''Shoshone River'' (after the tribe) and ''Saptin River''.
Early inhabitants
People have been living along the Snake River for at least 11,000 years. Historian Daniel S. Meatte divides the prehistory of the western Snake River Basin into three main phases or "adaptive systems". The first he calls "Broad Spectrum Foraging", dating from 11,500 to 4,200 years before present. During this period people drew upon a wide variety of food resources. The second period, "Semisedentary Foraging", dates from 4,200–250 years before present and is distinctive for an increased reliance upon fish, especially salmon, as well as
food preservation
Food preservation includes processes that make food more resistant to microorganism growth and slow the oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that inhibit ...
and storage. The third phase, from 250 to 100 years before present, he calls "Equestrian Foragers". It is characterized by large horse-mounted tribes that spent long amounts of time away from their local foraging range hunting bison. In the eastern Snake River Plain there is some evidence of Clovis,
Folsom Folsom may refer to:
People
* Folsom (surname)
Places in the United States
* Folsom, Perry County, Alabama
* Folsom, Randolph County, Alabama
* Folsom, California
* Folsom, Georgia
* Folsom, Louisiana
* Folsom, Missouri
* Folsom, New Jerse ...
, and
Plano cultures
The Plano cultures is a name given by archaeologists to a group of disparate hunter-gatherer communities that occupied the Great Plains area of North America during the Paleo-Indian or Archaic period.
Distinguishing characteristics
The Plano cu ...
dating back over 10,000 years ago.
Early fur traders and explorers noted regional trading centers, and archaeological evidence has shown some to be of considerable antiquity. One such trading center in the Weiser area existed as early as 4,500 years ago. The
Fremont culture
The Fremont culture or Fremont people is a pre-Columbian archaeological culture which received its name from the Fremont River in the U.S. state of Utah, where the culture's sites were discovered by local indigenous peoples like the Navajo and Ute ...
may have contributed to the historic Shoshones, but it is not well understood. Another poorly understood early cultural component is called the Midvale Complex. The introduction of the horse to the Snake River Plain around 1700 helped in establishing the Shoshone and
Northern Paiute
Northern may refer to the following:
Geography
* North, a point in direction
* Northern Europe, the northern part or region of Europe
* Northern Highland, a region of Wisconsin, United States
* Northern Province, Sri Lanka
* Northern Range, a r ...
cultures.
On the Snake River in southeastern Washington there are several ancient sites. One of the oldest and most well-known is called the Marmes Rockshelter, which was used from over 11,000 years ago to relatively recent times. The
Marmes Rockshelter
The Marmes Rockshelter (also known as (45-FR-50)) is an archaeological site first excavated in 1962, near Lyons Ferry Park and the confluence of the Snake River, Snake and Palouse Rivers, in Franklin County, Washington, Franklin County, southeaste ...
was flooded in 1968 by
Lake Herbert G. West
Lake Herbert G. West (or Lake West) is a reservoir formed by the Lower Monumental Dam in the U.S. state of Washington. It extends up the Snake River for 28 miles (45 km) to the tailwater of Little Goose Dam. It has a surface area of 6,590 acre ...
, the Lower Monumental Dam's reservoir..
Eventually, two large Native American groups controlled most of the Snake River: the Nez Perce, whose territory stretched from the southeastern Columbia Plateau into northern Oregon and western Idaho, and the Shoshone, who occupied the Snake River Plain both above and below Shoshone Falls. Lifestyles along the Snake River varied widely. Below Shoshone Falls, the economy centered on salmon, who often came up the river in enormous numbers. Salmon were the mainstay of the Nez Perce and most of the other tribes below Shoshone Falls. Above the falls, life was significantly different. The Snake River Plain forms one of the only relatively easy paths across the main Rocky Mountains for many hundreds of miles, allowing Native Americans both east and west of the mountains to interact. As a result, the Shoshone centered on a trading economy.
According to legend, the Nez Perce tribe was first founded in the valley of the Clearwater River, one of the Snake River's lowermost major tributaries. At its height, there were at least 27 Nez Perce settlements along the Clearwater River and 11 more on the Snake between the mouth of the Clearwater and
Imnaha River
The Imnaha River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed May 3, 2011 tributary of the Snake River in the U.S. state of Oregon. Flowing generally east near the headwaters a ...
s. There were also villages on the Salmon River, Grande Ronde River, Tucannon River, and the lower Hells Canyon area. The Snake River's annual salmon run, which was estimated at that time to exceed four million in good years, supported the Nez Perce, who lived in permanent, well-defined villages, unlike the nomadic southeastern tribes along the Snake River. The Nez Perce also were involved in trade with the Flathead Indian, Flathead tribe to the north and other middle Columbia River tribes. However, they were enemies to the Shoshone and the other upstream Snake River tribes.
The Shoshone (or Shoshoni) were characterized by nomadic groups that took their culture from the earlier Bitterroot culture and Great Basin tribes that migrated north via the Owyhee River. They were the most powerful tribe in the Rocky Mountains area, and were known to many Great Plains tribes as the "Snakes". In the 18th century, Shoshone territory extended beyond the Snake River Plain, extending over the Continental Divide into the upper Missouri River watershed and even further north into Canada. A smallpox epidemic brought by European explorers and fur trappers was responsible for wiping out much of the Shoshone east of the Rocky Mountains, but the Shoshone continued to occupy the Snake River Plain. Eventually, the Shoshone culture merged with that of the Paiute and Bannock (tribe), Bannock tribes, which came from the Great Basin and the Hells Canyon area, respectively. The Bannock brought with them the skill of bison, buffalo hunting and horses they had acquired from Europeans, changing the Shoshone way of life significantly.
Exploration and settling
The Lewis and Clark Expedition (1804–06) was the first American group to cross the Rocky Mountains and sail down the Snake and Columbia rivers to the Pacific Ocean.Gulick, p. 17 Meriwether Lewis supposedly became the first American to sight the drainage basin of the Snake River after he crossed the mountains a few days ahead of his party on August 12, 1805, and sighted the Salmon River valley (a major Snake tributary) from Lemhi Pass, a few miles from the present-day site of Salmon, Idaho. The party later traveled north, descended the Lemhi River to the Salmon and attempted to descend it to the Snake, but found it impassable because of its violent rapids. The expedition named the Snake River the ''Lewis River'', ''Lewis's River'', or ''Lewis Fork'', in his honor, and they traveled northwards to the Lochsa River, which they traveled via the Clearwater River into the lower Snake, and into the Columbia. They also referred to the Shoshone Indians as the "Snake Indians", which became the present-day name of the river. The name "Lewis Fork", however, did not last.
Later American explorers traveled throughout the Snake River area and up its major tributaries beginning in 1806, just after Lewis and Clark had returned. The first was John Ordway in 1806, who also explored the lower Salmon River. John Colter in 1808 was the first to sight the upper headwaters of the Snake River, including the Jackson Hole area.
In 1810, Andrew Henry (fur trader), Andrew Henry, along with a party of fur trappers, discovered the Henrys Fork of the Snake River, which is now named after him. Donald Mackenzie (explorer), Donald Mackenzie sailed the lower Snake River in 1811, and later explorers included Wilson Price Hunt of the Astor Expedition (who gave the river the name "Mad River"), Ramsay Crooks, Francisco Payelle, John Grey, Thyery Goddin, and many others after the 1830s. Many of these later explorers were original members of the Lewis and Clark Expedition who had returned to map and explore the area in greater detail. Even later, American fur trappers scouted the area for beaver streams, but Canadian trappers from the United Kingdom, British Hudson's Bay Company were by now a major competitor.
The Hudson's Bay Company first sent fur trappers into the Snake River watershed in 1819. The party of three traveled into the headwaters of the Owyhee River, a major southern tributary of the Snake, but disappeared. Meanwhile, as American fur trappers kept coming to the region, the Hudson's Bay Company ordered the Canadian trappers to kill as many beavers as they could, eventually nearly eradicating the species from the Snake River watershed, under the "rationale [that] if there are no beavers, there will be no reason for the Yanks ([Americans]) to come." Their goal was to eventually gain rights over the Oregon Territory, a region covering Washington, Oregon, Idaho, and parts of Montana and Wyoming (most of the present-day region called the Pacific Northwest). However, the area was eventually annexed into the United States.
By the middle 19th century, the Oregon Trail had been established, generally following much of the Snake River. One crossing the trail made over the Snake River was near the present-day site of Glenns Ferry, Idaho, Glenns Ferry. Several years later, a ferry was established at the site, replacing the old system where pioneers had to ford the wide, powerful and deep Snake. Another place where pioneers crossed the Snake was further upstream, at a place called "Three Island Crossing", near the mouth of the Boise River. This area has a group of three islands (hence the name) that splits the Snake into four channels each about wide. Some emigrants chose to ford the Snake and proceed down the west side and recross the river near Fort Boise into Hells Canyon, continue down the drier east side into the gorge, or float the Snake and Columbia to the Willamette River, the destination of the Oregon Trail. The reason for the Three Island Crossing was the better availability of grass and water access. Numerous ferries have provided crossings of the upper Snake from the Brownlee Ferry at the head of Hell's Canyon to Menor's Ferry, which operates today at Moose, Wyoming. Sophistication varied from reed boats pulled by Indians on horse back at Snake Fort, Fort Boise, as described by Narcissa Whitman in 1836 to an electric operated ferry, the Swan Falls Ferry, at Swan Falls Dam of the early 20th century.
One contemporary diarist crossing near Salmon Falls (Snake River), Salmon Falls complains of "exorbitant" fees at the crossings that were a "constant drain" on the traveler's purse. She writes that this particular route was controlled by Mormons who had "built bridges where they were not needed-most unmercifully fleecing the poor emigrants". The diarist expresses regret at having made the crossing describing the landscape as "desolate country". Another writer similarly notes several days travel through "a desert so desolate and rocky that we almost regretted that we had not continued on the south side of that stream".
Steamboats
Unlike the Columbia River, it was far more difficult for steamboats to navigate on the Snake. The Columbia River drops from source to mouth, while the Snake drops over in elevation over a length more than shorter. Still, from the 1860s to the 1940s, steamboats traveled on the Snake River from its mouth at the Columbia River to near the mouth of the Imnaha River in lower Hells Canyon. However, most of the steamboats only sailed from the river's mouth to Lewiston, located at the confluence of the Snake and Clearwater rivers. This stretch of the river is the easiest to navigate for watercraft since it has the least elevation change, although it still contained over 60 sets of rapids.
Passenger and freight service downstream of Lewiston lasted throughout the late 19th century and persisted until the introduction of railroads in the Palouse Hills grain-growing region and ultimately, the construction of dams on the lower Snake to facilitate barge traffic, which caused the demise of both the steamboats and the railroad. Lewiston, from the confluence of the Snake and Columbia and from the mouth of the Columbia on the Pacific Ocean, became connected with Portland, Oregon, Portland and other Pacific ports via steamboat service from the mouth of the Snake through the Columbia River Gorge. A commonly traveled route was from Wallula, Washington, downstream of the Snake River's mouth, upstream to Lewiston. The Oregon Steam Navigation Company launched the Shoshone (Snake River sternwheeler), Shoshone at Fort Boise in 1866 which provided passenger and freight service on the upper Snake for the Boise and Owyhee mines.
By the 1870s, the OSN Company, owned by the Northern Pacific Railroad, was operating seven steamboats for transporting wheat and grain from the productive Palouse region along the Snake and Columbia to lower Columbia River ports. These boats were the ''Harvest Queen'', ''John Gates'', ''Spokane'', ''Annie Faxon (sternwheeler), Annie Faxon'', ''Mountain Queen'', ''R.R. Thompson'', and ''Wide West'', all of which were built on the Columbia River. However, there were more resources along the Snake River than wheat and grain. In the 1890s, a huge copper deposit was discovered at Eureka Bar in Hells Canyon. Several ships were built specifically to transport ore from there to Lewiston: these included ''Imnaha'', ''Mountain Gem'', and ''Norma''. In 1893 the ''Annie Faxon'' suffered a boiler explosion and sank on the Snake below Lewiston.
River modifications
Dams
A total of fifteen dams have been constructed along the Snake River for a multitude of different purposes, from its headwaters in the Rocky Mountains to its mouth on
Lake Wallula
Lake Wallula is a reservoir on the Columbia River in the United States, between the U.S. states of Washington (U.S. state), Washington and Oregon. It was created in 1954 with the construction of McNary Dam. It reaches from McNary Dam near the city ...
, the reservoir formed behind McNary Dam on the Columbia River. Dams on the Snake can be grouped into three major categories.
*From its headwaters to the beginning of Hells Canyon, many small dams block the Snake to provide irrigation water. Between the headwaters and Hells Canyon, the first dam on the Snake, Swan Falls Dam, was built in 1901.
*In Hells Canyon, a cascade of dams produce
hydroelectricity
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other Renewabl ...
from the river's steep fall over a comparatively short distance.
*Finally, a third cascade of dams, from Hells Canyon to the mouth, facilitates navigation. Many different government and private agencies have worked to build dams on the Snake River, which now serve an important purpose for people living in the drainage basin and trade of agricultural products to Pacific seaports.
The Minidoka Irrigation Project of the U.S. Bureau of Reclamation, created with the passage of the Reclamation Act of 1902, involved the diversion of Snake River water into the Snake River Plain upstream of Shoshone Falls in order to irrigate approximately in the Snake River Plain and store of water in Snake River reservoirs.
The first studies for irrigation in the Snake River Plain were conducted by the United States Geological Survey in the late 19th century, and the project was authorized on April 23, 1904. The first dam constructed for the project was Minidoka Dam in 1904; its power plant began operating in 1909, producing 7 MW of electricity. This capacity was revised to 20 MW in 1993.
Jackson Lake Dam, far upstream in Wyoming's
Grand Teton National Park
Grand Teton National Park is an American national park in northwestern Wyoming. At approximately , the park includes the major peaks of the Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Grand Teton Na ...
, was built in 1907 to raise Jackson Lake for providing additional water storage in dry years.
American Falls Dam
The American Falls Dam is a concrete gravity-type dam located near the town of American Falls, Idaho, on river mile 714.7 of the Snake River. The dam and reservoir are a part of the Minidoka Project on the Snake River Plain and are used primaril ...
, upstream of Minidoka, was completed in 1927 and replaced in 1978. As the dams were constructed above Shoshone Falls, the historical upriver limit of salmon and also a total barrier to boats and ships, no provisions were made for fish passage or navigation. Several other irrigation dams were also built - including Twin Falls (Idaho), Twin Falls Dam and
Palisades Dam
Palisades Dam () is an earth-fill dam in the western United States, on the upper Snake River in eastern Idaho. Located in Bonneville County near the Wyoming border, the dam was completed in 1957.
Providing irrigation water, flood control, a ...
.
The Hells Canyon Project was built and maintained by Idaho Power starting in the 1940s and was the second of the three major water projects on the river. The three dams of the project, Brownlee Dam, Oxbow Dam and Hells Canyon Dam, are located in upper Hells Canyon. All three dams are primarily for power generation and flood control and do not have fish passage or navigation locks.
Brownlee Dam, the most upriver dam, was constructed in 1959 and generates 728 megawatts (MW). Oxbow Dam, the second dam in the project, was built in 1961 and generates 220 MW. The dam was named for a bend in the Snake River, shaped like an oxbow. Hells Canyon Dam was the last and most downriver of the three. It was constructed in 1967 and generates 450 MW.
Downriver of Hells Canyon is the Lower Snake River Project, authorized by the Rivers and Harbors Act#List of later acts, Rivers and Harbors Act of 1945 for the U.S. Army Corps of Engineers to create a navigable channel on the Snake River from its mouth to the beginning of Hells Canyon. These dams are, from upstream to downstream: Lower Granite Lock and Dam, Little Goose Lock and Dam, Lower Monumental Lock and Dam, and Ice Harbor Lock and Dam. Dredging work was also done throughout the length of the navigation channel to facilitate ship passage. These dams form a cascade of reservoirs with no stretches of free-flowing river in between. Immediately below Ice Harbor Dam is Lake Wallula, formed by the construction of the McNary Dam on the Columbia River. (McNary Dam is not part of the Lower Snake River Project.) Above Lower Granite Dam, the river channel from Lewiston to Johnson Bar, Idaho, Johnson Bar, just below Hells Canyon, is also maintained for jet-boats as this section is too rugged for ships.
These dams have been proposed for removal, and if they were to be removed, it would be the largest dam removal project ever undertaken in the United States. The removal has been proposed on the grounds that it would restore salmon runs to the lower Snake River and the Clearwater River and other smaller tributaries. Idaho's Snake river once teemed with sockeye salmon. However, there are almost no wild sockeye salmon left in the river due to a number of factors.
Sockeye Salmon are reduced in number on this river that runs through three different states and is over long. Salmon swimming upstream in this river are faced with predators and dams. The Snake River has fifteen dams and is extremely difficult for salmon to access because of hydroelectric dams. Hell's Canyon Dam blocks passage to the entire upper Snake River. The Grand Coulee Dam also blocks spawning grounds to the famous "June Hogs" (legendary Chinook salmon that weighed over ).
Between 1985 and 2007, only an average of 18 sockeye salmon returned to Idaho each year. Serious conservation efforts by wildlife biologists and fish hatcheries have captured the few remaining wild sockeye salmon, collected their sperm and eggs, and in a laboratory, have them spawn. Instead of spawning naturally, these sockeye begin their lives in an incubator in a fishery biologist's laboratory. These baby salmon then are transported by ship, bypassing the dams. (The dams can hurt juvenile baby sockeye salmon with their powerful tides and currents, which suck the baby salmon down.) Another conservation effort that has helped the salmon recover, is the destruction of old, outdated dams, such as the Lewiston Dam on the Clearwater River, a tributary of the Snake. After destroying the dam, salmon populations noticeably recovered.
Another recovery method conservationists and biologists are using is called Fish Transportation. Since many juvenile salmon perish at each dam while swimming out to the ocean, ships filter and collect these baby salmon by size and take them out to the ocean, where they can be guaranteed to make it alive to saltwater. This method raises controversy to the effectiveness and costs, since this method is extremely expensive, almost costing $15 million. Another possible upstream passage solution is the Whooshh Fish Transport System. Engineers at Whooshh Innovations have developed a fish passage system that allows for the safe and timely transportation of fish over barriers through a flexible tube system via volitional entry into the system.
Overall, these combined efforts have had good success. In the summer of 2006, the Snake River reportedly only had 3 sockeye salmon that returned to their spawning grounds. In the summer of 2013, more than 13,000 sockeye salmon returned to the spawning grounds.
Navigation
In the 1960s and 1970s the U.S. Army Corps of Engineers built four dams and locks on the lower Snake River to facilitate shipping. The lower Columbia River has likewise been dammed for navigation. Thus a deep channel (geography), shipping channel through locks and slackwater reservoirs for heavy barges exists from the Pacific Ocean to Lewiston, Idaho. Most barge traffic originating on the Snake River goes to deep-water ports on the lower Columbia River, such as Portland. Grain, mostly wheat, is the main product shipped from the Snake, and nearly all of it is exported internationally from the lower Columbia River ports.
The shipping channel is authorized to be at least deep and wide. Where river depths were less than , the shipping channel has been dredged in most places. Dredging and redredging work is ongoing and actual depths vary over time. With a channel about deeper than the Mississippi River system, the Columbia and Snake rivers can float barges twice as heavy. Agricultural products from Idaho and eastern Washington are among the main goods transported by barge on the Snake and Columbia rivers. Grain, mainly wheat, accounts for more than 85% of the cargo barged on the lower Snake River. In 1998, over of grain were barged on the Snake. Before the completion of the lower Snake dams, grain from the region was transported by truck or rail to Columbia River ports around the Tri-Cities. Other products barged on the lower Snake River include peas, lentils, forest products, and petroleum.
Biology
The World Wide Fund for Nature (WWF) divides the Snake River's watershed into two freshwater ecoregions: the "Columbia Unglaciated" ecoregion and the "Upper Snake" ecoregion. Shoshone Falls marks the boundary between the two. The WWF placed the ecoregion boundary about downriver from Shoshone Falls in order to include the Big Wood River (the main tributary of the Malad River) in the Upper Snake ecoregion, because the Wood River is biologically distinct from the rest of the downriver Snake. Shoshone Falls has presented a total barrier to the upstream movement of fish for 30,000 to 60,000 years. As a result, only 35% of the fish fauna above the falls, and 40% of the Wood River's fish fauna, are shared with the lower Snake River.
The Upper Snake freshwater ecoregion includes most of southeastern Idaho and extends into small portions of Wyoming, Utah, and Nevada, including major freshwater habitats such as Jackson Lake. Compared to the lower Snake River and the rest of the Columbia River's watershed, the Upper Snake ecoregion has a high level of endemism, especially among freshwater molluscs such as Gastropoda, snails and Bivalvia, clams. There are at least 21 snail and clam species of special concern, including 15 that appear to exist only in single clusters. There are 14 fish species found in the Upper Snake region that do not occur elsewhere in the Columbia's watershed, but which do occur in Bonneville freshwater ecoregion of western Utah, part of the Great Basin and related to the prehistoric Lake Bonneville. The Wood River sculpin (''Cottus leiopomus'') is endemic to the Wood River. The Shoshone sculpin (''Cottus greenei'') is endemic to the small portion of the Snake River between Shoshone Falls and the Wood River.
The Snake River below Shoshone Falls is home to thirty-five native fish species, of which twelve are also found in the Columbia River and four of which are endemic to the Snake: the relict sand roller (''Percopsis transmontana'') of the family Percopsidae, the shorthead sculpin (''Cottus confusus''), the margined sculpin (''Cottus marginatus''), and the Oregonichthys, Oregon chub (''Oregonichthys crameri''). The Oregon chub is also found in the Umpqua River and nearby basins. The lower Snake River also supports seven species of Pacific salmon and trout (''Oncorhynchus''). There are also high, often localized levels of mollusc endemism, especially in Hells Canyon and the basins of the Clearwater River, Salmon River, and middle Snake River. The mollusc richness extends into the lower Columbia River and tributaries such as the Deschutes River (Oregon), Deschutes River.
Animals
Aside from aquatic species, much of the Snake River watershed supports larger animals including numerous species of mammals, birds, amphibians, and reptiles. Especially in the headwaters and the other mountainous areas strewn throughout the watershed, the gray wolf, grizzly bear, wolverine, mountain lion and Canada lynx are common. It has been determined that there are 97 species of mammals in the upper part of the Snake River, upstream from the Henrys Fork confluence. Pronghorn and bighorn sheep are common in the area drained by the "lost streams of Idaho", several rivers and large creeks that flow south from the Rocky Mountains and disappear into the Snake River Aquifer. About 274 bird species, some endangered or threatened, use the Snake River watershed, including bald eagle, peregrine falcon, whooping crane, greater sage-grouse, and yellow-billed cuckoo. Barrow's goldeneye are a species of bird that occurs commonly along the lower section of the Snake River.
Ten amphibian and twenty species of reptiles inhabit the upper Snake River's wetland and riparian zones. Several species of amphibians are common in the "lost streams" basin and the northeasternmost part of the Snake River watershed, including the tailed frog, inland tailed frog, northern leopard frog, western toad, Columbia spotted frog, long-toed salamander, American Spadefoot Toads, spadefoot toad. However, in the lower and middle portions of the Snake River watershed, several native species have been severely impacted by agriculture practices and the resulting non-native species supported by them. Introduced birds include the gray partridge, ring-necked pheasant, and Chukar partridge, chukar. Other non-native species include the American bullfrog, bullfrog, brown-headed cowbird, and European starling, attracted by the construction of cities and towns.
Plants
The Snake River watershed includes a diversity of vegetation zones both past and present. A majority of the watershed was once covered with shrub-steppe grassland, most common in the Snake River Plain and also the Columbia Plateau in southeastern Washington. Riparian zones, wetlands and marshes once occurred along the length of the Snake River and its tributaries. In higher elevations, conifer forests, of which ponderosa pine is most common, dominate the landscape. The basin ranges from semi-desert to alpine climates, providing habitat for hundreds of species of plants. In the lowermost part of the watershed, in southeastern Washington, the Snake River is surrounded by an area called the Columbia Plateau Ecoprovince, which is now mostly occupied by irrigated farms. The rest of the Plateau area is characterized by low hills, dry lakes, and an arid, nearly desert climate.
The headwaters of the Snake River and the high mountains elsewhere in the watershed were historically heavily forested. These include aspen, Douglas fir, and spruce fir, comprising about 20% of the historic watershed. At the base of mountains and in the Lost River basin, sagebrush was and is the predominant vegetation cover. Because of deforestation, up to one quarter of the forests have been taken over by sagebrush, leaving the remaining forests to cover about 15% of the watershed. However, the lodgepole pine has increased in number, taking over historic stands of other conifers. There are also up to 118 species of rare or endemic plants that occur in the Snake River watershed.
Salmon and other anadromous fish
The Snake River was once one of the most important rivers for the spawning of anadromous fish—which are hatched in the headwaters of rivers, live in the ocean for most of their lives, and return to the river to spawn—in the United States.
The river supported species including chinook salmon, coho salmon, and sockeye salmon, as well as Rainbow trout, steelhead, white sturgeon, and Pacific lamprey. It is known that before the construction of dams on the river, there were three major chinook salmon runs in the Snake River; in the spring, summer and fall, totaling about 120,000 fish, and the sockeye salmon run was about 150,000. The historical barrier to fish migration on the Snake River was Shoshone Falls, a waterfall that occurs as the Snake River passes through the Snake River Plain.
Since the early 20th century, when Swan Falls Dam was constructed on the middle Snake River upstream of Hells Canyon, the fifteen dams and reservoirs on the river have posed an increasing problem for migrating salmon. Agricultural lands and their resulting runoff have also had a significant impact on the success rate of migrating fish. Salmon can travel up the Snake River as far as Hells Canyon Dam, using the fish passage facilities of the four lower Snake River dams, leaving the Clearwater, Grande Ronde and Salmon river to sustain spawning salmon. Rising in several forks in the Clearwater Mountains of central Idaho, the Clearwater and Salmon River watersheds are nearly undeveloped with the enormous exception of Dworshak Dam on the North Fork Clearwater River. The watershed of the Grande Ronde in northeastern Oregon is also largely undeveloped. The four reservoirs formed by the lower Snake River dams—Lake Sacajawea (Washington), Lake Sacagawea, Lake Herbert G. West, Lake Bryan, and Lower Granite Lake—have also formed problems, as the downstream current in the pools is often not enough for the fish to sense, confusing their migration routes.
At the confluence of the Snake and Clearwater Rivers, young salmon that swim down from spawning gravels in the headwaters of the Clearwater River often delay their migrations because of a significant temperature difference. (Prior to the removal of Dam removal#Completed dam removal projects, Lewiston Dam on the main Clearwater and South Fork Clearwater River, Grangeville Dam on the South Fork Clearwater River, South Fork Clearwater, the Clearwater was completely unusable by migrating salmon.) Agricultural runoff and water held in reservoirs higher upstream on the Snake warm its waters as it flows through the Snake River Plain, so as the Snake meets the Clearwater, its average temperature is much higher. Directly below the confluence, the river flows into Lower Granite Lake, formed by Lower Granite Dam, the uppermost dam of the Lower Snake River Project. Paradoxically, the combination of these factors gives the young salmon further time to grow and to feed in Lower Granite Lake, so when they begin the migration to the Pacific Ocean, they often have a higher chance at survival, compared to those salmon who migrate to the ocean earlier.
Lower Snake River dam removal
A controversy has erupted since the late 20th century over the four lower Snake River dams, with the primary argument being that removing the dams would allow anadromous fish to reach the lower Snake River tributaries—the Clearwater River, the Tucannon River and the Grande Ronde River—and spawn in much higher numbers. However, removal of the dams has been fiercely opposed by some groups in the Pacific Northwest. Because much of the electricity in the Northwest comes from dams, removing the four dams would create a hole in the energy grid that would not be immediately replaceable. Navigation on the lower Snake would also suffer, as submerged riffles, rapids and islands would be exposed by the removal of the dams. Irrigation pumps for fields in southeastern Washington would also have to reach further to access the water of the Snake River. However, proponents for restoring salmon runs by dam removal argue that the power is replaceable, that the grain transportation system could be replaced by railroads, and that only one of the four reservoirs supplies irrigation water. Irrigators in the Snake River Plain would likely need to allow less water into the Snake River during low flow in order to create a current in the four lower reservoirs, and recreation and tourism would likely benefit.
Tributaries
The Salmon River is the second largest tributary. Although the Salmon has larger drainage than the Clearwater, the Salmon drains much drier country and therefore has a smaller discharger than the Clearwater, about annually compared to about annually for the Clearwater River.
The Snake River has over 20 major tributary, tributaries, most of which are in the mountainous regions of the basin. The largest by far is the Clearwater River, which drains in north central Idaho. Many of the rivers that flow into the Snake River Plain from the north sink into the Snake River Aquifer, but still contribute their water to the river. Aside from rivers, the Snake is fed by many significant springs, many of which arise from the aquifer on the west side of the plain.
See also
* Angling in Yellowstone National Park
* Fishes of Yellowstone National Park
* List of crossings of the Snake River
* List of tributaries of the Columbia River
* List of rivers of Idaho
* List of longest streams of Idaho
* List of longest rivers of the United States (by main stem)
* List of longest streams of Oregon
* List of National Wild and Scenic Rivers
* List of rivers of Oregon
* List of Washington rivers
* List of Wyoming rivers
* List of rivers in the United States
* Lost streams of Idaho
* Snake River Plain (ecoregion)
*
Snake River Plain
image:Snake River view near Twin Falls, Idaho.jpg, The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges, gorges, such as this one near Twin Falls, Idaho
The Snake River Plain is a geology, geologic feature ...
List of dams on the Snake River
{{Authority control
Lists of rivers of the United States by state, Idaho
Lists of landforms of Idaho, Rivers
Snake River,
Rivers of Idaho
Rivers of Oregon
Rivers of Washington (state)
Rivers of Wyoming
Rivers of Yellowstone National Park
Tributaries of the Columbia River
Physiographic sections
Wild and Scenic Rivers of the United States
Borders of Idaho
Borders of Oregon
Borders of Washington (state)
Rivers of Wallowa County, Oregon
Rivers of Baker County, Oregon
Rivers of Malheur County, Oregon
Rivers of Bonneville County, Idaho
Rivers of Madison County, Idaho
Rivers of Power County, Idaho
Rivers of Twin Falls County, Idaho
Rivers of Ada County, Idaho
Rivers of Owyhee County, Idaho
Rivers of Nez Perce County, Idaho
Rivers of Bingham County, Idaho
Rivers of Fremont County, Idaho
Rivers of Elmore County, Idaho
Rivers of Payette County, Idaho
Rivers of Gooding County, Idaho
Rivers of Canyon County, Idaho
Rivers of Washington County, Idaho
Rivers of Adams County, Idaho
Rivers of Idaho County, Idaho
Rivers of Jerome County, Idaho