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This article is about the river in the northwestern USA. For other uses, see Snake River (disambiguation).

The Snake is a major river of the greater Pacific Northwest in the United States. At 1,078 miles (1,735 km) long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean.^[1] Rising in western Wyoming, the river flows through the Snake River Plain then rugged Hells Canyon and the rolling Palouse Hills to reach its mouth at the Tri-Cities of the state of Washington. Its drainage basin encompasses parts of six U.S. states, and its average discharge is over 54,000 cubic feet per second (1,500 m³/s).

Rugged mountains divided by rolling plains characterize the physiographically diverse watershed of the Snake River. The Snake River Plain was created by a volcanic hotspot which now lies underneath Yellowstone National Park, the headwaters of the Snake River. Gigantic glacial-retreat flooding episodes that occurred during the previous Ice Age carved out many topographical features including various canyons and ridges along the middle and lower Snake. Two of these catastrophic flooding events significantly affected the river and its surrounds.

More than 11,000 years ago, prehistoric Native Americans lived along the Snake. Salmon from the Pacific Ocean spawned in the millions in the river. These fish were central to the lives of the people along the Snake below Shoshone Falls. By the time Lewis and Clark crossed the Rockies and sighted the valley of a Snake tributary, the Nez Perce and Shoshone were the most powerful people in the region. Contact with Europeans introduced horses to some tribes, reshaping their lifestyles for the next few hundred years before outside settlement. Later explorers and fur trappers further changed and utilized the resources of the Snake River basin. At one point, a hand sign made by the Shoshones representing fish was misinterpreted to represent a snake, giving the Snake River its name.

By the middle 19th century, the Oregon Trail, a pioneer trail of which a major portion followed the Snake River, had been established. Steamboats and railroads moved agricultural products and minerals along the river throughout the 19th and early 20th centuries. The powerful, steep flow of the Snake has been utilized since the 1890s to generate hydroelectricity, enhance navigation and provide irrigation water from fifteen major dams that have transformed the lower river into a series of reservoirs, several of which have been proposed for removal to restore some of the river's once tremendous salmon runs.

Course

Formed by the confluence of three tiny headstreams on the southwest flank of Two Oceans Plateau in western Wyoming and Yellowstone National Park, the Snake starts out as a small river flowing west and south into Jackson Lake. Its first 50 miles (80 km) run through the valley of Jackson Hole, which cuts between the Teton Range and the Continental Divide. The Snake takes a large bend northwest through Snake River Canyon, cutting through the Snake River Range and into eastern Idaho, receiving first the Hoback and Greys Rivers before entering Palisades Reservoir where it is also met by the Salt River at the mouth of Star Valley. After passing through Palisades Dam, the Snake River empties onto the Snake River Plain, a vast physiographic province extending through southern Idaho across the massif of the Rocky Mountains and underlain by the Snake River Aquifer, one of the most productive aquifers in the United States.^[2]^[3]^[4]^[5]^[6]

Southwest of the city of Rexburg, the Snake receives from the right the Henrys Fork, sometimes called the North Fork of the Snake River. The confluence with the Henrys Fork takes the river southwards through downtown Idaho Falls, rounding the Fort Hall Indian Reservation and into American Falls Reservoir, receiving the Portneuf River. The Portneuf River valley is an overflow channel that in the last glacial period carried floodwaters from pluvial Lake Bonneville into the Snake River Plain, carving out many topographic features and significantly altering the Snake River landscape. The Snake River resumes its journey westwards, then enters the Snake River Canyon of Idaho, where it drops over Shoshone Falls, a waterfall that marks the historical upriver limit of migrating salmon,^[2]^[7]^[8] and passing under the Perrine Bridge.^[3]^[9] Close to Twin Falls, the Snake approaches the southernmost point in its entire course, after which it starts to flow generally northwest.^[2]^[3]^[5]^[6]

Shortly after it passes within 30 miles (48 km) of the Idaho state capital of Boise, the river surges past the state border into Oregon, close to where it meets the Owyhee River, Boise River and Payette River. The Snake River then begins to define the roughly 200-mile-long (320 km) Idaho-Oregon state border, which follows the river into Hells Canyon, a steep and spectacular 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, which pioneers on the Oregon Trail and steamboat operators in the 19th century had great difficulty negotiating. There were hundreds of rapids in Hells Canyon, some of which have been stilled by the three dams of the Hells Canyon Hydroelectric Project: Hells Canyon, Oxbow, and Brownlee.^[2]^[5]^[6]^[10]

The Salmon River, the largest tributary of the Snake River, meets the river in one of the remotest areas of its entire course, nearly at the halfway point in Hells Canyon. From there, the Snake crosses into Washington and Idaho, receiving the Grande Ronde River from the west before receiving the Clearwater River at Lewiston, the uppermost major city on the navigable stretch of the Snake. As the Snake leaves Hells Canyon and spreads into the low-lying Palouse Hills of eastern Washington, the Lower Snake River Project's four dams have transformed the Snake River into a series of reservoirs. The confluence of the Snake and Columbia rivers has been submerged in Lake Wallula, the reservoir of McNary Dam. The Columbia River then flows about 325 miles (523 km) further to the Pacific Ocean, cutting through the Cascade Range by way of the Columbia River Gorge.^[2]^[5]^[6]

Geology

As recently as 165 million years ago, most of western North America was still part of the Pacific Ocean. The nearly complete subduction of the Farallon Plate underneath the westward-moving North American Plate created the Rocky Mountains, which were pushed up by rising magma trapped between the sinking Farallon and the North American plate. As the North American Plate moved westwards over a stationary hotspot beneath the crust, a series of tremendous lava flows and volcanic eruptions carved out the Snake River Plain beginning about 12 million years ago, west of the Continental Divide.^[11] Even larger lava flows of Columbia River basalts issued over eastern Washington, forming the Columbia Plateau southeast of the Columbia and the Palouse Hills in the lower Snake.^[12] Separate volcanic activity formed the northwestern portion of the plain, an area far from the path of the hotspot which now lies beneath Yellowstone National Park.^[11] At this point, the Snake River watershed was beginning to take shape.

Locations of the Yellowstone hotspot as it passed through the Snake River Plain

The Snake River Plain and the gap between the Sierra Nevada and Cascade Range formed a "moisture channel" running as far inland as the headwaters of the Snake River. Rainclouds from the Pacific Ocean blown into the moisture channel travel eastwards over 1,000 miles (1,600 km). When the Teton Range uplifted about 9 million years ago along a detachment fault running north-south through the central Rockies,^[13] rainclouds began to encounter a barrier at the eastern end of the channel, gorging the headwaters of the Snake River with frequent rainfall. These rains fed the Snake River, helping it to cut through the Tetons, 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, and as the river cut through the rising mountains, the ancestral Hells Canyon was formed. Lake Idaho, formed during the Miocene, covered a large portion of the Snake River Plain between Twin Falls and Hells Canyon, and its lava dam was finally breached about 2 million years ago.^[14]

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. A 40-mile (64 km)-long 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 Lake Bonneville in the Great Salt Lake area, formed in the last glacial period, spilled catastrophically down the Portneuf River into the Snake in an event known as the Bonneville Flood.^[15] 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 away with only the 50-foot (15 m)-high American Falls left in the end. The flood waters of Lake Bonneville, approximately twenty times the flow of the Columbia River or 5,300,000 cubic feet per second (150,000 m³/s), swept down the Snake River leaving debris and sediment deposits across southern Idaho. For miles on either side of the Snake flood waters stripped away soils and scoured the underlying basalt bedrock, in the process creating Shoshone Falls, Twin Falls, Crane Falls, and Swan Falls, while cutting and deepening gorges and canyons along the way.^[16] The Bonneville flood waters continued through Hells Canyon. The flood widened Hells Canyon but did not deepen it.^[17]^[18]

As the Bonneville Floods rushed down the Snake River, the Missoula Floods occurred in the same period, but farther north. The Missoula Floods, which took place over 40 times in the time span from 15,000 to 13,000 years ago, were caused by Glacial Lake Missoula 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 of the Snake River watershed, carving deep canyons through the Palouse Hills. The Palouse River canyon was the largest of the many gorges cut through the Palouse Hills, and could not have become as large as it now is if it were not for the Missoula Floods. The Lake Bonneville floods and the Missoula Floods helped widen and deepen the Columbia River Gorge, a giant water gap which allows water from the Columbia and Snake rivers to take a direct route through the Cascade Range to the Pacific.^[17]^[19]^[20]

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 of the mostly-basalt 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.^[21] The aquifer filled to hold nearly 100,000,000 acre-feet (120 km³) of water, underlying about 10,000 square miles (26,000 km²) in a plume 1,300 feet (400 m) thick.^[22] In places, water exits from rivers at rates of nearly 600 cubic feet per second (17 m³/s).^[16] 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 springs.^[4]^[23]^[24]

Watershed

By length the Snake River is the thirteenth largest river in the United States.^[1] Its watershed is the tenth largest among North American rivers, and covers almost 108,000 square miles (280,000 km²) in portions of six U.S. states: Wyoming, Idaho, Nevada, Utah, Oregon, and Washington, 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.^[25]^[26] Above the confluence, the Snake is slightly longer than the Columbia—1,078 miles (1,735 km)^[27] compared to 928 miles (1,493 km)^[28]—and its drainage basin is slightly larger—4% bigger than the upstream Columbia River watershed.^[29]^[30]

The mostly semi-arid, even desert climate of the Snake River watershed on average, as a whole, typically receives less than 12 inches (300 mm) of precipitation 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 9.24 inches (235 mm), although the average snowfall is 13.1 inches (330 mm).^[31] 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 discharge is on average significantly less. However, in the high Rockies of Wyoming, in the upper Jackson Hole area, the average precipitation is over 30 inches (760 mm), and snowfall averages 252 inches (6,400 mm).^[32] 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. 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, Hells Canyon National Recreation Area, and many other national and state parks.

Map of the Columbia River basin with the Snake River highlighted in yellow and the Columbia river in blue

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, 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 in Wyoming, Twin Falls, Idaho Falls, Boise, and Lewiston in Idaho, and the Tri-Cities in Washington (Kennewick, 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.^[33] However, fish passage is limited to the stretch below Hells Canyon.^[34]

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 basins. On the southwest side a divide separates the Snake watershed from Oregon's Harney Basin, which is endorheic. On the south, the Snake watershed borders that of the Humboldt River in Nevada, and the watershed of the Great Salt Lake (the Bear, Jordan and Weber rivers) on the south.^[35] The Snake River also shares a boundary with the Green River to the southeast; the Green River drains parts of Wyoming and Utah and is the largest tributary of the Colorado River. On the western extremity for a short stretch the Continental Divide separates the Snake watershed from the Bighorn River, a tributary of the Yellowstone River, 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, which flows into the Jefferson River and into the Missouri River, part of the Gulf of Mexico drainage basin.^[35]

The rest of the Snake River watershed borders on several other major Columbia River tributaries - mostly the Spokane River to the north, but also Clark Fork in Montana to the northeast and the John Day River to the west. Of these, the Clark Fork (via the Pend Oreille River) 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.^[35]

Mountain ranges in the Snake watershed include the Teton Range, Bitterroot Range, Clearwater Mountains, Seven Devils Mountains, and the extreme northwestern end of the Wind River Range. Grand Teton is the highest point in the Snake River watershed, reaching 13,775 feet (4,199 m) in elevation. The elevation of the Snake River is 358 feet (109 m) when it joins the Columbia River.^[36]

Pollution

Agricultural runoff from farms and ranches in the Snake River Plain and many other areas has severely hurt the ecology of the river throughout the 20th century. After the first irrigation dams on the river begun operation in the first decade of the 20th century, much of the arable land in a strip a few miles wide along the Snake River was cultivated or turned to pasture, and agricultural return flows began to pollute the Snake. Runoff from several feedlots was dumped into the river until laws made the practice illegal.^[37] Fertilizer, manure and other chemicals and pollutants washed into the river greatly increase the nutrient load, especially of phosphorus, fecal coliforms and nitrogen. During low water, algae blooms occur throughout the calm stretches of the river, depleting its oxygen supply.^[38]

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.^[39] Throughout much of the Snake River Plain and Hells Canyon, excessive sediment is also a recurring problem.^[40] In December 2007, the U.S. Environmental Protection Agency (EPA) issued a permit requiring owners of fish farms along the Snake River to reduce their phosphorus discharge by 40 percent. 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.^[41]

Discharge

The Snake River's average flow is 54,830 cubic feet per second (1,553 m³/s). The United States Geological Survey recorded the river's discharge from a period of 1963–2000 at a stream gauge below Ice Harbor Dam. In that period, the largest average annual flow recorded was 84,190 cubic feet per second (2,384 m³/s) in 1997, and the lowest was 27,100 cubic feet per second (770 m³/s) in 1992.^[42] The lowest recorded daily mean flow was 2,700 cubic feet per second (76 m³/s) 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 312,000 cubic feet per second (8,800 m³/s) on June 19, 1974.^[42] 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 369,000 cubic feet per second (10,400 m³/s)—more than the Columbia's average discharge—on May 29, 1948. An even larger peak discharge, estimated at 409,000 cubic feet per second (11,600 m³/s), occurred during the flood of June, 1894.^[43]

The river's flow is also measured at several other points in its course. Above Jackson Lake, Wyoming, the discharge is about 885 cubic feet per second (25.1 m³/s) from a drainage area of 486 square miles (1,260 km²).^[44] At Minidoka, Idaho, about halfway through the Snake River Plain, the river's discharge rises to 7,841 cubic feet per second (222.0 m³/s).^[45] However, at Buhl, Idaho, only about 50 miles (80 km) downstream, the river's flow decreases to 4,908 cubic feet per second (139.0 m³/s) because of agricultural diversions and seepage.^[46] But at the border of Idaho and Oregon, near Weiser at the beginning of Hells Canyon, the Snake's flow rises to 17,780 cubic feet per second (503 m³/s) after receiving several major tributaries such as the Payette, Owyhee and Malheur.^[47] The discharge further increases to 19,530 cubic feet per second (553 m³/s) at Hells Canyon Dam on the border of Idaho and Oregon.^[48] At Anatone, Washington, downstream of the confluence with the Salmon, one of the Snake's largest tributaries, the mean discharge is 34,560 cubic feet per second (979 m³/s).^[49]

History

Name

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 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 was the first of their group to sight the river.^[50] They also made note of the "Snake Indians" who lived along the river, who were actually the Shoshone tribe, and learned that the Native Americans called the river Ki-moo-e-nim or Yam-pah-pa (for a herb that grew prolifically along its banks).^[51] 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 of the Astor Expedition named the river as Mad River. Others gave the river names including Shoshone River (after the tribe) and Saptin River.^[36] Eventually, the name Snake River was derived from an S-shaped gesture the Shoshone tribe made with their hands to represent swimming salmon. Explorers misinterpreted it to represent a snake, giving the river its present-day name.^[52]

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 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.^[53] In the eastern Snake River Plain there is some evidence of Clovis, Folsom, and Plano cultures 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 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 cultures.^[54]^[55]

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 was flooded in 1968 by Lake Herbert G. West, the Lower Monumental Dam's reservoir.^[56]

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 around 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 around 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 Rivers. 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 tribe to the north and other middle Columbia River tribes. However, they were enemies to the Shoshone and the other upstream Snake River tribes.^[57]

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.^[58] 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 tribes, which came from the Great Basin and the Hells Canyon area, respectively. The Bannock brought with them the skill of buffalo hunting and horses they had acquired from Europeans, changing the Shoshone way of life significantly.^[59]

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.^[60] 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. as a result 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.^[61]^[62] The name "Lewis Fork", however, did not last.^[60]

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.^[63] In 1810, 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 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"),^[64] Ramsay Crooks, Francisco Payelle, John Grey, Thyery Goddin, and many others after the 1830s.^[63] 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 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.^[65] 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."^[65] 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).^[66] However, the area was eventually annexed into the United States, and England lost its claim on Canada.

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 Ontario, Oregon. 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 200 feet (61 m) 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.^[67] Numerous ferries have provided crossings of the upper Snake from the Brownlee Ferry at the head of Hell's Canyon^[68] to Menor's Ferry,^[69] 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^[70] in 1836 to an electric operated ferry, the Swan Falls Ferry,^[71] at Swan Falls Dam of the early 20th century.

Steamboats

Unlike the Columbia River, it was far more difficult for steamboats to navigate on the Snake. The Columbia River drops 2,690 feet (820 m) from source to mouth, while the Snake drops over 8,500 feet (2,600 m) in elevation over a length more than 200 miles (320 km) 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.^[72] However, most of the steamboats only sailed from the river's mouth to Lewiston, located at the confluence of the Snake and Clearwater rivers.^[73] 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.^[74]

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, 140 miles (230 km) from the confluence of the Snake and Columbia and 465 miles (748 km) from the mouth of the Columbia on the Pacific Ocean, became connected with Portland and other Pacific ports via steamboat service from the mouth of the Snake through the Columbia River Gorge.^[75] A commonly traveled route was from Wallula, Washington, 120 miles (190 km) downstream of the Snake River's mouth, upstream to Lewiston.^[76] The Oregon Steam Navigation Company launched the Shoshone at Fort Boise in 1866 which provided passenger and freight service on the upper Snake for the Boise and Owyhee mines.^[77]

By the 1870s, the OSN Company, owned by the Northern Pacific Railroad, was operating seven steamboats for transporting wheat and grain from the producive Palouse region along the Snake and Columbia to lower Columbia River ports. These boats were the Harvest Queen, John Gates, Spokane, Annie Faxon, Mountain Queen, R.R. Thompson, and Wide West, all of which were built on the Columbia River.^[78] 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.^[79] A disaster in 1893 involved Annie Faxon sinking on the Snake below Lewiston because of a boiler explosion.^[73]^[80]

River modifications

Dams

Many factors have influenced the construction of dams along the Snake River. 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 Umatilla. 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 here 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 from the river's lofty decrease in elevation over a comparatively small 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 Snake's 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 1,100,000 acres (4,500 km²) in the Snake River Plain and store 4,100,000 acre-feet (5.1 km³) of water in Snake River reservoirs.^[81] The first studies for irrigation in the Plain were conducted by the U.S. Geological Survey in the late 19th century, and the project was authorized on April 23, 1904.^[82] 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.^[83] However, Minidoka Dam was not the only dam constructed for the project. As far upstream as Jackson Lake in Wyoming, the Jackson Lake Dam was built in 1907 to raise the lake level for providing additional water storage for dry years. American Falls Dam, upstream of Minidoka, was completed in 1927 and replaced in 1978.^[82] 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 Dam and Palisades Dam.

Brownlee Dam, the uppermost dam of the Hells Canyon Project

The Hells Canyon Project was built and maintained by Idaho Power Company 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.^[84] Brownlee Dam, the most upriver dam, was constructed in 1959, and generates 728 MW of power. Oxbow Dam, the second dam in the project, was built in 1961 and generates 220 MW. The dam was named for a 3-mile (4.8 km)-wide bend in the Snake River, shaped like an oxbow, although not an oxbow lake. Hells Canyon Dam was the last and most downriver of the three, was constructed in 1967 and generates 450 MW.^[33]

Downriver of the Hells Canyon is the Lower Snake River Project, authorized by the Rivers and Harbors Act of 1945, which was created by 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.^[85] These dams are, in downstream order: 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, just below Hells Canyon, is also maintained for ships.^[86] 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.^[87] 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, although there would be a loss of hydroelectric power generated by the dams.^[88]

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 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 14 feet (4.3 m) deep and 250 feet (76 m) wide. Where river depths were less than 14 feet (4 m), the shipping channel has been dredged in most places. Dredging and redredging work is ongoing and actual depths vary over time.^[89] With a channel about 5 feet (1.5 m) deeper than the Mississippi River system, the Columbia and Snake rivers can float barges twice as heavy.^[90] 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 123,000,000 US bushels (4.3×10⁹ L; 980,000,000 US dry gal; 950,000,000 imp gal) 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.^[89]

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 50 kilometres (31 mi) 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.^[91]^[92]

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 snails and clams. There are at least twenty-one snail and clam species of special concern, including fifteen which appear to exist only in single clusters. There are fourteen 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.^[93]

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 Percopsidae family, the shorthead sculpin (Cottus confusus), the maginated sculpin (Cottus marginatus), and the 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 salmon (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.^[93]

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.^[3] 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.^[3]

In the middle reaches of the Snake River as it flows through the Snake River Plain, introduced species have fared better than native species

Ten amphibian and twenty species of reptiles inhabit the upper Snake River's wetland and riparian zones. Several species of frogs are common in the "lost streams" basin and the northeasternmost part of the Snake River watershed, including the inland tailed frog, Northern leopard frog, western toad, Columbia spotted frog, long-toed salamander, spadefoot toad.^[3] 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. Other non-native species include the bullfrog, brown-headed cowbird, and European starling, attracted by the construction of cities and towns.^[94]

Plants

The Snake River watershed includes a diversity of vegetation zones both past and present.^[3] 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.^[94]

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-fourth 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.^[3]

Salmon and anadromous fish

The Snake River was once one of the most important rivers for the spawning of anadromous fish—which are born 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.^[95]^[96] The river supported species including chinook salmon, coho salmon, and sockeye salmon, as well as steelhead trout, 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.^[95]

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 Rivers 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 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.^[10]^[97]

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 Lewiston Dam on the main Clearwater and Grangeville Dam on the South Fork Clearwater, the Clearwater was completely unusable by migrating salmon.^[98]) 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.^[97]

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.^[99] 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.^[100] 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, aside from restoring salmon runs, dam removal proponents 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.^[101]^[102]

In response to conflicts, a bill has been introduced in the U.S. Congress proposing the study of the feasibility of removing these four lower dams.^[103]^[104] The issue of dam removal was not in the recovery plan set forth by the Obama Administration in September 2009. The plan instead recommended monitoring the effects of climate change and expanding habitat improvement efforts, leaving dam removal as “a last resort” contingent upon a multiyear study of the dams.^[105] In February 2010 U.S. Circuit Judge James Redden deemed this plan to be inadequate and gave NOAA three months to formulate a better plan.^[106] The plan was resubmitted in May 2010 with few substantial changes^[107] and has faced strong opposition from salmon advocates. A final decision from Judge Redden is expected in the spring of 2011.^[108]

Tributaries

The Salmon river is the second largest tributary. Although the Salmon has a larger drainage than the Clearwater, the Salmon drains much drier country and therefore has a smaller discharger than the Clearwater, about 8,000,000 acre-feet (9.9 km³) annually compared to about 11,000,000 acre-feet (14 km³) annually for the Clearwater river.

Henrys Fork is the largest tributary upstream of the Snake River Plain

The Snake River has over twenty major tributaries, most of which are in the mountainous regions of the basin. The largest by far is the Clearwater River, which drains 9,000 square miles (23,000 km²) 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.^[3]

Name	Length	Watershed size	Bank
Source to Wyoming-Idaho Border
Heart River	8.5 miles (13.7 km)		Right
Lewis River	12 miles (19 km)		Right
Gros Ventre River		642 square miles (1,660 km²)	Left
Hoback River	55 miles (89 km)	600 square miles (1,600 km²)	Left
Greys River	65 miles (105 km)	800 square miles (2,100 km²)	Left
Salt River	70 miles (110 km)	890 square miles (2,300 km²)	Left
Snake River Plain to Hells Canyon
Henrys Fork (Snake River)	110 miles (180 km)	3,212 square miles (8,320 km²)	Right
Portneuf River	96 miles (154 km)	1,329 square miles (3,440 km²)	Left
Raft River		1,506 square miles (3,900 km²)	Left
Malad River	11.5 miles (18.5 km)	3,000 square miles (7,800 km²)	Right
Salmon Falls Creek	218 miles (351 km)	2,082 square miles (5,390 km²)	Left
Bruneau River		3,305 square miles (8,560 km²)	Left
Boise River	75 miles (121 km)	4,100 square miles (11,000 km²)	Right
Owyhee River	280 miles (450 km)	11,049 square miles (28,620 km²)	Left
Malheur River	165 miles (266 km)	4,700 square miles (12,000 km²)	Right
Payette River	62 miles (100 km)	3,240 square miles (8,400 km²)	Right
Hells Canyon
Weiser River	90 miles (140 km)	1,660 square miles (4,300 km²)	Right
Burnt River	50 miles (80 km)		Left
Salmon River	425 miles (684 km)	14,000 square miles (36,000 km²)	Right
Grande Ronde River	212 miles (341 km)	4,000 square miles (10,000 km²)	Left
Clearwater River	80 miles (130 km)	9,645 square miles (24,980 km²)	Right
Idaho-Washington border to mouth
Tucannon River	70 miles (110 km)	503 square miles (1,300 km²)	Left
Palouse River	140 miles (230 km)	3,303 square miles (8,550 km²)	Right

The Snake River bends through Hells Canyon on the Idaho-Oregon border, looking towards Idaho, with the Oxbow Dam in the background

References

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^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ "Upper Snake Province Assessment" (PDF). Northwest Watershed Council. 2004-05-28. Retrieved 2009-10-24.
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^ ^a ^b ^c ^d USGS Topo Maps for United States (Map). Cartography by United States Geological Survey. ACME Mapper. Retrieved 2010-04-12.
^ "Shoshone Falls". South Central Idaho Virtual Tour. College of Southern Idaho. Retrieved 2009-10-04.
^ "Shoshone Falls". Berkeley GeoImages Project. Retrieved 2009-10-04.
^ "I.B. Perrine Bridge". Structurae. Retrieved 2009-10-04.
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^ "The Lake Bonneville Flood". Digital Atlas of Idaho. Retrieved 2009-10-26.
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^ Smith, Richard P. (2004). "Geologic Setting of the Snake River Plain Aquifer and Vadose Zone" (PDF). Vadose Zone Journal. GeoScienceWorld. Retrieved 2009-10-04.
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^ The percentage is calculated by adding the discharge at Priest Rapids Dam on the Columbia to the discharge at Ice Harbor Dam on the Snake. Priest Rapids is the closest USGS gage upstream of the Snake confluence that has a reliable discharge record.
^ "USGS Gage #12472800 on the Columbia River below Priest Rapids Dam, WA (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-26.
^ Cite error: The named reference NHD was invoked but never defined (see the help page).
^ Upstream Columbia mileage calculated by subtracting 325 (Snake River confluence mile) from 1243 (the length of the Columbia). 325 miles below the Snake confluence comes from river mileage markers on USGS topo maps.
^ Cite error: The named reference USGS was invoked but never defined (see the help page).
^ The watershed of the Columbia upstream of the Snake River confluence is 97,190 square miles (251,700 km²), just slightly smaller than that of the Snake.
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^ "Snake River, Wyoming Period of Record Monthly Climate Summary". Western Regional Climate Center. 1905-06-21 to present. Retrieved 2009-10-07. {{cite web}}: Check date values in: |date= (help)
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^ Ritter, William F. (2001). Agricultural nonpoint source pollution: watershed management and hydrology. CRC Press. p. 170. ISBN 1-56670-222-4. {{cite book}}: More than one of |first1= and |first= specified (help); More than one of |last1= and |last= specified (help)
^ Philip, Jeff (2004-09-13). "EPA Approves Pollution Limits for Snake River-Hells Canyon". U.S. Environmental Protection Agency. Retrieved 2009-10-11.
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^ "USGS Gage #13081500 on the Snake River near Minidoka, ID (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.
^ "USGS Gage #13094000 on the Snake River near Buhl, ID (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.
^ "USGS Gage #13269000 on the Snake River near Weiser, ID (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.
^ "USGS Gage #13290454 on the Snake River at Hells Canyon Dam, Idaho-Oregon state line (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.
^ "USGS Gage #13290454 on the Snake River near Anatone, WA (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.
^ Gulick, Bill (1971). Snake River country. Caxton Press. ISBN 0-87004-215-7.
^ Hunger, Bill (2008). Hiking Wyoming: 110 of the State's Best Hiking Adventures (2 ed.). Globe Pequot. p. 234. ISBN 0-7627-3420-5.
^ "Snake River (Hells Canyon)". National Wild and Scenic Rivers Program. Retrieved 2009-10-04.
^ Summary of Western Snake River Prehistory, Digital Atlas of Idaho
^ Meatte, Daniel S. (1990). "The Fremont Culture". The Prehistory of the Western Snake River Basin. Digital Atlas of Idaho. Retrieved 2009-10-05.
^ Meatte, Daniel S. (1990). "The Midvale Complex". Prehistory of the Western Snake River Basin. Digital Atlas of Idaho. Retrieved 2009-10-04.
^ "Marmes Rockshelter" HistoryLink.
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^ Madsen, Brigham D. (1980). The Northern Shoshoni. Caxton Press. pp. 18–19. ISBN 0-87004-266-1.
^ Madsen, Brigham D. (1996). The Bannock of Idaho. University of Idaho Press. p. 20. ISBN 0-89301-189-4.
^ ^a ^b Gulick, p. 17
^ Lewis, Meriwether; Moulton, Gary E. (2003). The Lewis and Clark journals: An American epic of discovery. University of Nebraska Press. ISBN 0-8032-2950-X. {{cite book}}: More than one of |first1= and |first= specified (help); More than one of |last1= and |last= specified (help)
^ Lavender, David Sievert (2001). The way to the western sea: Lewis and Clark across the continent. University of Nebraska Press. p. 251. ISBN 0-8032-8003-3.
^ ^a ^b "Snake River Explorers" (PDF). Idaho State Historical Society Reference Series. Idaho State Historical Society. April 1992. Retrieved 2009-10-05.
^ Gulick (Snake River country), p. 24
^ ^a ^b Kaza, Roger. "Hudson's Bay Company". Engines of our Ingenuity. University of Houston. Retrieved 2009-10-05.
^ Gulick Snake River country), p. 32
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^ Maxwell, Rebecca (2009-10-12). "Brownlee Ferry". Historical Marker Database. Retrieved 2009-12-10.
^ "Grand Tetons, Cunningham Cabin, Nick Wilson, Menor's Ferry". Jackson Hole Photo Gallery. Wyoming Tales and Trails. Retrieved 2009-12-10.
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^ Gulick, Bill (2004). Steamboats on Northwest Rivers. Caxton Press. p. 40. ISBN 0-87004-438-9.
^ ^a ^b Dougherty, Phil (2006-04-09). "Steamers on the Lower Snake". HistoryLink.org. Retrieved 2009-10-05.
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^ Steamboats on Northwest Rivers, p. xiii
^ Steamboats on Northwest Rivers, p. 93
^ Carrey, John (1979). Snake River of Hells Canyon. Backeddy Books. pp. 32–42. ISBN 0-9603566-0-6.
^ Steamboats on Northwest Rivers, p. 122
^ Steamboats on Northwest Rivers, p. 162
^ Williamson, Darcy (1997). River Tales of Idaho. Caxton Press. p. 160. ISBN 0-87004-378-1.
^ Fiege, Mark (1999). Irrigated Eden: the making of an agricultural landscape in the American West. University of Washington Press. p. 95. ISBN 0-295-97757-4.
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^ "Minidoka Project History". Pacific Northwest Region Dams & Projects. U.S. Bureau of Reclamation. 2008-02-09. Retrieved 2009-10-06.
^ "Hells Canyon". Idaho Power. Retrieved 2009-10-06.
^ "Snake River (Oregon, Washington and Idaho)". USACE Walla Walla District. U.S. Army Corps of Engineers. 1994-09-30. Retrieved 2009-10-04.
^ "Lewiston, Idaho to Johnson Bar". USACE Walla Walla District. U.S. Army Corps of Engineers. 1994-09-30. Retrieved 2009-10-06.
^ Joshi, Pratik (2009-08-01). "Bill opens possibility of Lower Snake River dam removal". Tri-City Herald.
^ "Analysis of Snake River dam removal has deficiencies, economists report". Northwest Power and Conservation Council. 2007-03-14. Retrieved 2009-10-07.
^ ^a ^b "Lower Snake River Transportation Study Final Report" (PDF). BST Associates. American Rivers. 2003-06. Retrieved 2009-10-07. {{cite web}}: Check date values in: |date= (help)
^ Harden, Blaine (1996) A River Lost: The Life and Death of the Columbia, W.W. Norton & Company. ISBN 0-393-31690-4
^ "Columbia Unglaciated". World Wide Fund for Nature and the Nature Conservancy. Freshwater Ecoregions of the World. Retrieved 2010-04-14.
^ "Upper Snake". World Wide Fund for Nature and the Nature Conservancy. Freshwater Ecoregions of the World. Retrieved 2010-04-14.
^ ^a ^b Abell, Robin A. (2000). Freshwater Ecoregions of North America: A Conservation Assessment. Island Press. pp. 167–169. ISBN 1-55963-734-X. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b Ashley, Paul R.; Stovall, Stacey H. (2004). "Southeast Washington Subbasin Planning Ecoregion Wildlife Assessment" (PDF). Northwest Watershed Council. Retrieved 2009-10-24.
^ ^a ^b "Lower Snake River Juvenile Salmon Migration Feasibility Report/Environmental Impact Statement: Appendix M, Fish and Wildlife Coordination Act Report" (PDF). U.S. Army Corps of Engineers. U.S. Fish and Wildlife Service Conservation Library. December 1999. Retrieved 2009-10-23.
^ "Decline and Recovery of Snake River Salmon" (PDF). School of Fisheries. University of Washington. 1995-06. Retrieved 2010-04-14. {{cite web}}: Check date values in: |date= (help)
^ ^a ^b "Salmon migration mystery explored on Idaho's Clearwater River" (PDF). Pacific Northwest National Laboratory. U.S. Fish and Wildlife Service. 2009-09-15. Retrieved 2009-10-23.
^ "Removal of the Grangeville & Lewiston Dams in Idaho" (PDF). Dam Removal Success Stories. American Rivers. Retrieved 2009-10-23.
^ Preusch, Matt (2009-04-15). "Poll: Northwest voters oppose Snake River dam removal". Oregon Environmental News. OregonLive. Retrieved 2009-10-23.
^ "Replacing lower Snake River dams would cost Northwest $413 million to $565 million annually" (PDF). Bonneville Power Administration. April 2007. Retrieved 2009-10-23. ^{[dead link]}
^ "The Economics of Lower Snake River Dam Removal" (PDF). American Rivers. Retrieved 2009-10-23.
^ "Working Snake River Project". Retrieved 2009-10-23. (Note: This website requires a log-in that was not required on the date the website was accessed.)
^ Learn, Scott (2009-08-03). "Salmon bill would put removal of Snake River dams back on table". Oregon Environmental News. Oregon Live. Retrieved 2009-10-27.
^ H.R.3503 - Salmon Solutions and Planning Act (opencongress.org) and H.R. 3503: Salmon Solutions and Planning Act (govtrack.us)
^ Yardley, William (2009-09-15). "Obama Follows Bush on Salmon Recovery". The Seattle Times. Retrieved 2011-03-23.
^ Barnard, Jeff (2010-02-19). "NOAA Takes Back Plan Making Dams Safer for Salmon". The Seattle Times. Retrieved 2011-03-23.
^ Haight, Abby (2010-05-20). "Feds: No Major Changes for Columbia Basin Salmon". The Seattle Times. Retrieved 2011-03-31.
^ "Feds File Last round in Fight over Salmon and Dams". The Seattle Times. 2010-12-23. Retrieved 2011-03-30.

External links

Idaho Power
Wild and Scenic Snake River - National Wild and Scenic Rivers System
The Snake River in Grand Teton National Park
List of dams on the Snake River

[USGSrivers-1] Kammerer, J.C. (May 1990). "Largest Rivers in the United States". U.S. Geological Survey. Retrieved 2008-01-26.

[TributaryBasins-2] "Snake River Tributary Basins". Idaho Water Resources Research Institute at Idaho Falls. University of Idaho, Idaho Falls. Retrieved 2009-10-04.

[uppersnakeprovince-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ "Upper Snake Province Assessment" (PDF). Northwest Watershed Council. 2004-05-28. Retrieved 2009-10-24.

[groundwater-4] "Eastern Snake River Plain Surface and Ground Water Interaction". Idaho Water Resources Research Institute at Idaho Falls. University of Idaho, Idaho Falls. Retrieved 2009-10-04.

[topoquest-5] United States Geological Survey. "United States Geological Survey Topographic Maps". TopoQuest. Retrieved 2010-04-12.

[ACMEmapper-6] USGS Topo Maps for United States (Map). Cartography by United States Geological Survey. ACME Mapper. Retrieved 2010-04-12.

[7] "Shoshone Falls". South Central Idaho Virtual Tour. College of Southern Idaho. Retrieved 2009-10-04.

[8] "Shoshone Falls". Berkeley GeoImages Project. Retrieved 2009-10-04.

[9] "I.B. Perrine Bridge". Structurae. Retrieved 2009-10-04.

[HellsCanyonDamProjects-10] "Hells Canyon Dam". Columbia River History. Northwest Power and Conservation Council. Retrieved 2009-11-10.

[SRPGeology-11] Link, Paul. "Neogene Snake River Plain-Yellowstone Volcanic Province". Digital Geology of Idaho. Idaho State University Department of Geosciences. Retrieved 2009-10-04.

[12] Staub, Kristen; Link, Paul. "Geology, Age and Extent of the Columbia River Basalts". Digital Geology of Idaho. Idaho State University. Retrieved 2009-11-10.

[13] "The Story Begins". Creation of the Teton Landscape: The Geologic Story of Grand Teton National Park. National Park Service. 2007-01-19. Retrieved 2010-01-11.

[14] "Lake Idaho - Hulls Gulch National Recreation Trail". BLM Four Rivers Field Office. U.S. Bureau of Land Management. Retrieved 2009-10-05.

[15] "Lake Bonneville and the Bonneville Flood". USGS Cascades Volcano Observatory, U.S. National Park Service. United States Geological Survey. Retrieved 2009-10-05.

[PNGeology-16] Orr, Elizabeth L. (1996). Geology of the Pacific Northwest. McGraw-Hill. pp. 241–248. ISBN 0-07-048018-4. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[HellsCanyonGeology-17] "Geology of Hells Canyon". U.S. Forest Service. Retrieved 2009-10-05.

[18] "The Lake Bonneville Flood". Digital Atlas of Idaho. Retrieved 2009-10-26.

[19] "About the Floods". Ice Age Floods Institute. 2008-08-18. Retrieved 2009-10-05.

[20] "Channeled Scablands: Overview". Department of Geography and Geology. University of Wisconsin. Retrieved 2009-10-07.

[21] "Idaho's treasure; the Eastern Snake River Plain Aquifer" (PDF). State of Idaho Oversight Monitor. Idaho Department of Environmental Quality. May 2005. Retrieved 2009-10-04.

[22] Smith, Richard P. (2004). "Geologic Setting of the Snake River Plain Aquifer and Vadose Zone" (PDF). Vadose Zone Journal. GeoScienceWorld. Retrieved 2009-10-04.

[USGSnawqa-23] "Upper Snake River Basin". National Water Quality Assessment Program. USGS Idaho Water Science Center. Retrieved 2009-10-04.

[springs-24] "Snake River Plain Regional Aquifer System". Ground Water Atlas of the United States: Idaho, Oregon, Washington. United States Geological Survey. Retrieved 2009-10-05.

[25] The percentage is calculated by adding the discharge at Priest Rapids Dam on the Columbia to the discharge at Ice Harbor Dam on the Snake. Priest Rapids is the closest USGS gage upstream of the Snake confluence that has a reliable discharge record.

[26] "USGS Gage #12472800 on the Columbia River below Priest Rapids Dam, WA (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-26.

[NHD-27] Cite error: The named reference NHD was invoked but never defined (see the help page).

[28] Upstream Columbia mileage calculated by subtracting 325 (Snake River confluence mile) from 1243 (the length of the Columbia). 325 miles below the Snake confluence comes from river mileage markers on USGS topo maps.

[USGS-29] Cite error: The named reference USGS was invoked but never defined (see the help page).

[30] The watershed of the Columbia upstream of the Snake River confluence is 97,190 square miles (251,700 km²), just slightly smaller than that of the Snake.

[31] "Twin Falls, Idaho Period of Record Monthly Climate Summary". Western Regional Climate Center. 1980-02-01 to present. Retrieved 2009-10-07. {{cite web}}: Check date values in: |date= (help)

[32] "Snake River, Wyoming Period of Record Monthly Climate Summary". Western Regional Climate Center. 1905-06-21 to present. Retrieved 2009-10-07. {{cite web}}: Check date values in: |date= (help)

[IdahoPowerDams-33] "Hydroelectric Plants". Idaho Power. Retrieved 2009-10-06.

[34] "Fish passage at dams". Columbia River History. Northwest Power and Conservation Council. Retrieved 2009-10-07.

[NorthAmericaWatersheds-35] Watersheds (Map). Cartography by CEC, Atlas of Canada, National Atlas, Instituto Nacional de Estadística y Geografía. Commission for Environmental Cooperation (CEC). Archived from the original on 2008-02-27. Retrieved 2009-10-08.

[GNISsnake-36] "Snake River". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.

[37] Wolf, Carissa (2006-02-01). "Dirty Water: Ag pollution in rural wells runs deep". Boise Weekly. Retrieved 2009-10-11.

[38] "Pollution of the Snake River". Ecology and Conservation. Central Washington Native Plants. Retrieved 2009-10-11.

[39] "Groundwater Resources". Digital Atlas of Idaho. Idaho Museum of Natural History. Retrieved 2009-10-11.

[40] Ritter, William F. (2001). Agricultural nonpoint source pollution: watershed management and hydrology. CRC Press. p. 170. ISBN 1-56670-222-4. {{cite book}}: More than one of |first1= and |first= specified (help); More than one of |last1= and |last= specified (help)

[41] Philip, Jeff (2004-09-13). "EPA Approves Pollution Limits for Snake River-Hells Canyon". U.S. Environmental Protection Agency. Retrieved 2009-10-11.

[iceharbordam-42] "Snake River below Ice Harbor Dam, WA" (PDF). National Water Information System. United States Geological Survey. 1963–2000. Retrieved 20 April 2011.{{cite web}}: CS1 maint: date format (link)

[usace-43] "Ice Harbor Lock and Dam Pertinent Data". U.S. Army Corps of Engineers. 1915–1972. Retrieved 20 April 2011.

[44] "USGS Gage #13010065 on the Snake River above Jackson Lake at Flagg Ranch, WY (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-24.

[45] "USGS Gage #13081500 on the Snake River near Minidoka, ID (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.

[46] "USGS Gage #13094000 on the Snake River near Buhl, ID (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.

[47] "USGS Gage #13269000 on the Snake River near Weiser, ID (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.

[48] "USGS Gage #13290454 on the Snake River at Hells Canyon Dam, Idaho-Oregon state line (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.

[49] "USGS Gage #13290454 on the Snake River near Anatone, WA (Water-Data Report 2009)" (PDF). National Water Information System. United States Geological Survey. Retrieved 2010-09-25.

[50] Gulick, Bill (1971). Snake River country. Caxton Press. ISBN 0-87004-215-7.

[51] Hunger, Bill (2008). Hiking Wyoming: 110 of the State's Best Hiking Adventures (2 ed.). Globe Pequot. p. 234. ISBN 0-7627-3420-5.

[52] "Snake River (Hells Canyon)". National Wild and Scenic Rivers Program. Retrieved 2009-10-04.

[53] Summary of Western Snake River Prehistory, Digital Atlas of Idaho

[Fremont-54] Meatte, Daniel S. (1990). "The Fremont Culture". The Prehistory of the Western Snake River Basin. Digital Atlas of Idaho. Retrieved 2009-10-05.

[55] Meatte, Daniel S. (1990). "The Midvale Complex". Prehistory of the Western Snake River Basin. Digital Atlas of Idaho. Retrieved 2009-10-04.

[56] "Marmes Rockshelter" HistoryLink.

[57] Ruby, Robert H.; Brown, John Arthur (1992). A guide to the Indian tribes of the Pacific Northwest. University of Oklahoma Press. p. 145. ISBN 0-8061-2479-2.

[58] Madsen, Brigham D. (1980). The Northern Shoshoni. Caxton Press. pp. 18–19. ISBN 0-87004-266-1.

[59] Madsen, Brigham D. (1996). The Bannock of Idaho. University of Idaho Press. p. 20. ISBN 0-89301-189-4.

[gulick17-60] Gulick, p. 17

[61] Lewis, Meriwether; Moulton, Gary E. (2003). The Lewis and Clark journals: An American epic of discovery. University of Nebraska Press. ISBN 0-8032-2950-X. {{cite book}}: More than one of |first1= and |first= specified (help); More than one of |last1= and |last= specified (help)

[62] Lavender, David Sievert (2001). The way to the western sea: Lewis and Clark across the continent. University of Nebraska Press. p. 251. ISBN 0-8032-8003-3.

[explorers-63] "Snake River Explorers" (PDF). Idaho State Historical Society Reference Series. Idaho State Historical Society. April 1992. Retrieved 2009-10-05.

[64] Gulick (Snake River country), p. 24

[EOI-65] Kaza, Roger. "Hudson's Bay Company". Engines of our Ingenuity. University of Houston. Retrieved 2009-10-05.

[66] Gulick Snake River country), p. 32

[67] "Three Island Crossing". The Oregon Trail in Idaho. Idaho State Historical Society. Retrieved 2009-10-08.

[68] Maxwell, Rebecca (2009-10-12). "Brownlee Ferry". Historical Marker Database. Retrieved 2009-12-10.

[69] "Grand Tetons, Cunningham Cabin, Nick Wilson, Menor's Ferry". Jackson Hole Photo Gallery. Wyoming Tales and Trails. Retrieved 2009-12-10.

[70] Eells, Myron (1909). Marcus Whitman, pathfinder and patriot. Alice Harriman Company. Retrieved 2009-12-10.

[71] "Snake River Ferries" (PDF). Idaho State Historical Society. 1982-10. Retrieved 2009-12-10. {{cite web}}: Check date values in: |date= (help)

[72] Gulick, Bill (2004). Steamboats on Northwest Rivers. Caxton Press. p. 40. ISBN 0-87004-438-9.

[hlsteamboats-73] Dougherty, Phil (2006-04-09). "Steamers on the Lower Snake". HistoryLink.org. Retrieved 2009-10-05.

[74] "Recreation on a Free-Flowing Lower Snake River" (PDF). American Rivers. Retrieved 2009-10-27.

[75] Steamboats on Northwest Rivers, p. xiii

[76] Steamboats on Northwest Rivers, p. 93

[77] Carrey, John (1979). Snake River of Hells Canyon. Backeddy Books. pp. 32–42. ISBN 0-9603566-0-6.

[78] Steamboats on Northwest Rivers, p. 122

[79] Steamboats on Northwest Rivers, p. 162

[80] Williamson, Darcy (1997). River Tales of Idaho. Caxton Press. p. 160. ISBN 0-87004-378-1.

[81] Fiege, Mark (1999). Irrigated Eden: the making of an agricultural landscape in the American West. University of Washington Press. p. 95. ISBN 0-295-97757-4.

[MinidokaProject-82] "Minidoka Project". Pacific Northwest Dams & Projects. U.S. Bureau of Reclamation. 2009-06-19. Retrieved 2009-10-06.

[83] "Minidoka Project History". Pacific Northwest Region Dams & Projects. U.S. Bureau of Reclamation. 2008-02-09. Retrieved 2009-10-06.

[HellsCanyonProject-84] "Hells Canyon". Idaho Power. Retrieved 2009-10-06.

[LowerNavigation-85] "Snake River (Oregon, Washington and Idaho)". USACE Walla Walla District. U.S. Army Corps of Engineers. 1994-09-30. Retrieved 2009-10-04.

[86] "Lewiston, Idaho to Johnson Bar". USACE Walla Walla District. U.S. Army Corps of Engineers. 1994-09-30. Retrieved 2009-10-06.

[87] Joshi, Pratik (2009-08-01). "Bill opens possibility of Lower Snake River dam removal". Tri-City Herald.

[88] "Analysis of Snake River dam removal has deficiencies, economists report". Northwest Power and Conservation Council. 2007-03-14. Retrieved 2009-10-07.

[lsr-89] "Lower Snake River Transportation Study Final Report" (PDF). BST Associates. American Rivers. 2003-06. Retrieved 2009-10-07. {{cite web}}: Check date values in: |date= (help)

[90] Harden, Blaine (1996) A River Lost: The Life and Death of the Columbia, W.W. Norton & Company. ISBN 0-393-31690-4

[91] "Columbia Unglaciated". World Wide Fund for Nature and the Nature Conservancy. Freshwater Ecoregions of the World. Retrieved 2010-04-14.

[92] "Upper Snake". World Wide Fund for Nature and the Nature Conservancy. Freshwater Ecoregions of the World. Retrieved 2010-04-14.

[abell-93] Abell, Robin A. (2000). Freshwater Ecoregions of North America: A Conservation Assessment. Island Press. pp. 167–169. ISBN 1-55963-734-X. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[lowersnakewildlife-94] Ashley, Paul R.; Stovall, Stacey H. (2004). "Southeast Washington Subbasin Planning Ecoregion Wildlife Assessment" (PDF). Northwest Watershed Council. Retrieved 2009-10-24.

[salmon-95] "Lower Snake River Juvenile Salmon Migration Feasibility Report/Environmental Impact Statement: Appendix M, Fish and Wildlife Coordination Act Report" (PDF). U.S. Army Corps of Engineers. U.S. Fish and Wildlife Service Conservation Library. December 1999. Retrieved 2009-10-23.

[96] "Decline and Recovery of Snake River Salmon" (PDF). School of Fisheries. University of Washington. 1995-06. Retrieved 2010-04-14. {{cite web}}: Check date values in: |date= (help)

[ClearwaterSalmon-97] "Salmon migration mystery explored on Idaho's Clearwater River" (PDF). Pacific Northwest National Laboratory. U.S. Fish and Wildlife Service. 2009-09-15. Retrieved 2009-10-23.

[98] "Removal of the Grangeville & Lewiston Dams in Idaho" (PDF). Dam Removal Success Stories. American Rivers. Retrieved 2009-10-23.

[99] Preusch, Matt (2009-04-15). "Poll: Northwest voters oppose Snake River dam removal". Oregon Environmental News. OregonLive. Retrieved 2009-10-23.

[100] "Replacing lower Snake River dams would cost Northwest $413 million to $565 million annually" (PDF). Bonneville Power Administration. April 2007. Retrieved 2009-10-23. ^{[dead link]}

[101] "The Economics of Lower Snake River Dam Removal" (PDF). American Rivers. Retrieved 2009-10-23.

[102] "Working Snake River Project". Retrieved 2009-10-23. (Note: This website requires a log-in that was not required on the date the website was accessed.)

[103] Learn, Scott (2009-08-03). "Salmon bill would put removal of Snake River dams back on table". Oregon Environmental News. Oregon Live. Retrieved 2009-10-27.

[104] H.R.3503 - Salmon Solutions and Planning Act (opencongress.org) and H.R. 3503: Salmon Solutions and Planning Act (govtrack.us)

[105] Yardley, William (2009-09-15). "Obama Follows Bush on Salmon Recovery". The Seattle Times. Retrieved 2011-03-23.

[106] Barnard, Jeff (2010-02-19). "NOAA Takes Back Plan Making Dams Safer for Salmon". The Seattle Times. Retrieved 2011-03-23.

[107] Haight, Abby (2010-05-20). "Feds: No Major Changes for Columbia Basin Salmon". The Seattle Times. Retrieved 2011-03-31.

[108] "Feds File Last round in Fight over Salmon and Dams". The Seattle Times. 2010-12-23. Retrieved 2011-03-30.

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@@ Line 758: / Line 758: @@
 ===Lower Snake River dam removal===
-{{Very long section|date=March 2012}}
 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.<ref>{{cite web
 |url=http://www.webcitation.org/5p0d2Juaw
@@ Line 767: / Line 767: @@
 |last=Preusch
 |first=Matt
+|accessdate=2009-10-23}}</ref> 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.<ref>{{cite web
-|accessdate=2009-10-23}}</ref> The controversy is highly political. On one side, “Conservationists, coastal fishing communities, the state of Oregon, and the Nez Perce tribe<ref>{{cite news|last=VanDevelder|first=Paul|title=The reckoning:|url=http://www.oregonlive.com/opinion/index.ssf/2011/02/the_reckoning_a_looming_decisi.html|work=The Oregonian|date=2011-02-12}}</ref>”  that would sacrifice their economic gains for the sake of restoration of salmon. Against those pro-ecological restoration groups, “hydropower interests, aluminum industries, agribusiness, and political allies in Idaho, Washington and Montana<ref>{{cite news|last=VanDevelder|first=Paul|title=The reckoning: A looming decision on endangered salmon will set the stage for momentous battles over the future|url=http://www.oregonlive.com/opinion/index.ssf/2011/02/the_reckoning_a_looming_decisi.html|work=The Oregonian|date=2011-02-12}}</ref>”  pursue economic benefits over natural world. The concern regarding to the lower Snake River dams is highly controversial, since the existence of dams threatens one of the iconic species in Pacific Northwest.<ref>{{cite web|last=Peopel for Puget Sound|title=120 Western Washington business and community leaders seek leadership of Senators Murray and Cantwell in resolving Columbia Basin salmon crisis|url=http://pugetsound.org/news/news-about-people-for-puget-sound/061610dams/?searchterm=salmon}}</ref> At the same time, dams also carry important economic and social significance to the community; 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.<ref>{{cite web
+|url=http://www.bpa.gov/corporate/BPANews/Perspective/2007/Snake_River_Dams/Replacing_lower_Snake_River_dams.pdf
-|url=http://www.destonnokes.com/PDF-NCI/BPANews_Perspective_2007_Snake_River_Dams_Replacing_lower_Snake_River_dams.pdf
 |title=Replacing lower Snake River dams would cost Northwest $413 million to $565 million annually
 |publisher=Bonneville Power Administration
 |date=April 2007
+|accessdate=2009-10-23}} {{Dead link|date=September 2010|bot=H3llBot}}</ref> 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, aside from restoring salmon runs, dam removal proponents 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.<ref>{{cite web
-|accessdate=2009-10-23}}</ref>
-The lower Snake River dams provide enough energy to power a city the size of [[Seattle, Washington]]. These dams are [[Run-of-the-river hydroelectricity|run of the river]] dams, which means that they rely entirely on the amount of snowpack and the rate of runoff.<ref>Amy Baird. “Myths and Fact About Lower Snake River Dam Removal”. 24 Apr 2011. Internet Reserve</ref> Because these dams are rather ineffective, removal would not create a long term energy shortage, but it would take time to make up for the loss. 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, aside from restoring salmon runs, dam removal proponents 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.<ref>{{cite web
 |url=http://www.americanrivers.org/assets/pdfs/dam-removal-docs/lower_snake_econ_factsheet_06-05.pdf
 |title=The Economics of Lower Snake River Dam Removal
@@ Line 783: / Line 781: @@
 |title=Working Snake River Project
 |date=
 |accessdate=2009-10-23}} (Note: This website requires a log-in that was not required on the date the website was accessed.)</ref>
-[[File:BNSF Snake River Drawbridge.jpg|thumb|right|View of the Snake River's mouth with the Columbia in the background]]
 In response to conflicts, a bill has been introduced in the U.S. Congress proposing the study of the feasibility of removing these four lower dams.<ref>{{cite news
 |last=Learn
@@ Line 821: / Line 818: @@
 |date=2010-12-23
 |accessdate=2011-03-30}}</ref>
-The impacts of tourism and recreational activities in the lower Snake River area are highly beneficial. Removal of the dam would create a free-flowing river where recreational activities and tourism could take place. Restoring the lower Snake River would return many rapids, beaches and islands, and provide Washington State with {{convert|140|mi|km}} of big river recreation for water recreationists including jet boaters, kayakers and canoeists.<ref>{{cite web|title=Recreation and Tourism on a Working Snake River|url=http://www.workingsnakeriver.org/index.php?option=com_content&view=article&id=88&Itemid=138|work=Working Snake River for Washington|accessdate=31 May 2011}}</ref> Boating, kayaking, hunting, wildlife watching, hiking, camping and other related activities could bring an additional $310.5 million in non-fishing recreational income per year. According to a 2000 study for the Army Corps of Engineers – that’s about 10 times the economic value of current reservoir-based recreation on the lower Snake. The economic benefits could also be furthered by the improved quality of life that the removal of the dam would bring, drawing new businesses and residents to Snake River communities, help keep existing residents in town, and help increase property values. The dam removal and restoration effort itself could prove to be a tourism opportunity, as people are drawn to witness and learn about this historic event.<ref>{{cite web|last=Garrity|first=Michael|title=RECREATION ON A FREE-FLOWING LOWER SNAKE	RIVER: Outdoor opportunities, quality of life would greatly improve after dam removal|url=http://www.americanrivers.org/assets/pdfs/dam-removal-docs/lower_snake_rec_factsheet_3-05.pdf|work=American Rivers|publisher=American Rivers|accessdate=31 May 2011}}</ref>
-In addition to an increase in recreation and tourism, the economic benefit of reestablishing fish stocks would eventually outweigh the hydropower generated by the dams. The fish that migrate through the Lower Snake River are the Snake River Sockeye Salmon. Prior to dam construction these fish had one of the longest freshwater migrations on the planet, traveling over {{convert|1000|mi|km}} from the Pacific Ocean to Redfish Lake, Idaho, which is now blocked off because of these four dams. The Snake River has the highest, coolest, largest, best-protected habitat in the lower 48 states which would allow these salmon to thrive.<ref>"Why Restore Wild Salmon?" Save Our Wild Salmon. Web. 18 May 2011. <http://www.wildsalmon.org/index.php?option=com_content&view=article&id=94&Itemid=62>.
-</ref> The Snake River sockeye salmon are among the most resilient fish to warming and climate change because of their genetic diversity and long evolution process. Because of their long migration residing in Redfish Lake with a surface elevation of {{convert|6547|ft|m|abbr=on}}, these fish are well adapted and with a chance and place to spawn, these fish will rebound to historic numbers, allowing for positive economic opportunity (i.e. fishing).<ref>Kauffman, Jason. "Idaho Mountain Express: Is This Salmon Recovery? - September 10, 2008." The Valley's Newspaper. 10 Sept. 2008. Web. 18 May 2011. <http://www.mtexpress.com/index2.php?ID=2005122538>.
-</ref>
-The number of Wild Salmon is on the decline “The total annual run of all anadromous salmon in the basin, estimated at 10 to 16 million fish before European settlement, has declined to around one million fish, of which approximately 80% or more are now produced artificially in hatcheries.”<ref>Bottom, Daniel, Kim Jones, Charles Simenstad, and Courtland Smith. "Reconnecting Social and Ecological Resilience in Salmon Ecosystems." Ecology and Societ 14.</ref> Many argue that the best way to ensure these salmon are protected is the removal of dams, especially those four located in the lower Snake River. The removal of these dams will improve water conditions and water flow thus benefiting all thirteen species of stock salmon that migrate through the Columbia River. Although the dams do provide clean energy to Washington State, their removal will not hurt or inhibit the use of wind power.<ref>name=http://www.wildsalmon.org/index.php?option=com_content&view=article&id=149&Itemid=63#Myth%205</ref>
-The benefits of removing the lower Snake River dams are strong and should not be ignored or dismissed. Juvenile salmon, migrating through the lower Snake River dams reach mortality rates as high as 90%.<ref>Hawley, S. What don't we know about the Columbia salmon plan? http://www.oregonlive.com/opinion/index.ssf/2010/03/what_dont_we_know_about_the_co.html</ref> An extensive modeling effort of mortality analysis in 2000, showed that the lower four dams on the Snake river were the most significant factor preventing recovery.<ref name="wildsalmon.org">Why Remove The 4 Lower Snake River Dams? http://www.wildsalmon.org/index.php?option=com_content&view=article&id=348&Itemid=63</ref> Having to pass through eight dams is simply too hard for salmon, and removing these lower four dams would dramatically increase their numbers.<ref name="wildsalmon.org"/> Removing the dams will be beneficial to all 13 endangered species of salmon. Improved water quality and flow that would result from dam removal, would benefit all of the ESA listed species on the Columbia and Snake rivers.<ref>Myths and Facts about Lower Snake River Dam Removal. Myth 5. http://www.wildsalmon.org/index.php?option=com_content&view=article&id=149&Itemid=63#Myth%205</ref> One of the conservation efforts is the Lower Snake River Compensation Plan. This plan looks at the dams and found that these dams prevent the passage of many salmon and so we are now looking towards restoration efforts through hatcheries. The Lower Snake River Compensation Plan is looking to “compensate for the loss of 15% of the downstream-migrating juvenile salmon and steelhead. This amounts to a cumulative loss of 48% of the pre-dam runs.”.<ref>[http://www.nwcouncil.org/history/LowerSnakeComp.asp Lower Snake River Compensation Plan<!-- Bot generated title -->]</ref> Through this plan we hope to increase the overall juvenile salmon runs.
-Restoring salmon to the Snake River through the removal of the lower four dams has is a huge benefit. However, there are two other issues which should also be looked at in the consideration of the removal of these dams. The first benefit is the future safety of nearby towns to the these dams. Each year more sediment is eroded and is carried behind the dams. The Lower Granite Dam is 55% full of sediment, and each year that passes brings the nearby towns of Lewiston and Clarkston closer to a devastating flood.<ref>{{cite web|title=Why Remove The 4 Lower Snake River Dams?|url=http://www.wildsalmon.org/index.php?option=com_content&view=article&id=348&Itemid=63}}</ref> While other solutions have been thought of, they can only postpone such a flood, because the sediment will eventually pile up behind the dam once again. Many farmers are worried that the removal of the dams will deplete the water they use for irrigation. However this is not the case. In fact, intake pipes can be used instead of dams and take the water directly from the river.<ref>{{cite web|title=Myths and Facts about Lower Snake River Dam Removal|url=http://www.wildsalmon.org/index.php?option=com_content&view=article&id=149&Itemid=79}}</ref> Author Steven Hawley uses Lewiston, Idaho as an example of a town threatened by dams. In a lecture at the University of Washington, Hawley described how Lewiston was moving closer to being flooded each year due to sediment buildup.<ref>acwi.gov/sos/pubs/2ndJFIC/.../7C_Teasdale_041510_Abstract_for-papers.pdf</ref> Levees built to contain the water block the view of the river. Yet, Hawley said, many of the residents didn't see the immediacy of the situation, and he used their resistance to change as an example of the problems facing dam removal everywhere.<ref>Hawley, lecture April 26, 2011, UW</ref> Removing dams and taking water directly from rivers saves water because a free flowing river will evaporate less than a reservoir. By piping water directly to the farmers, a lot of water that would be normally evaporated, remains in the river.
-As described in David Montgomery’s book, King of Fish, the Columbia River basin only supports about seven salmon for every fifty salmon the basin had supported one-hundred-and-fifty years ago. Only one or two of those fish are wild and non-hatchery raised as well.<ref>{{cite book|last=Montgomery|first=David|title=King of Fish The Thousand-Year Run of Salmon|year=2003|publisher=Westview Press|isbn=0-8133-4299-6}}</ref>  There are numerous competing uses of the Columbia River, such as hydropower, flood control, navigation, irrigation agriculture, and salmon fishing. However, Columbia River management currently benefits certain interests and strategies are inadequate to restore salmon populations. Dam removal is necessary for restoration and recovery of salmon, but politics get in the way. Save Our Wild Salmon website also recommends removing the four lower Snake River dams, which they believe would enable salmon to rebound with more habitat and easier passage on their journey to the ocean. The website criticizes the government for spending eight million dollars on salmon recovery that has failed. In addition the Save Our Wild Salmon group disapproves of the government for getting around legal requirements and politicizing science - ignoring sound science.<ref>{{cite web|title=Save our Wild Salmon Coalition|url=http://www.wildsalmon.org/|accessdate=2011-04-24}}</ref>
-[[File:IcHrbrDam-1.jpg|thumb|left|Ice Harbor Dam, the lowermost of the four proposed to be removed]]
-The return of these fish will also significantly benefit the surrounding vegetation and animals that live upstream from the dams.  Before the dams were created, salmon migrated up and down the Snake River, transporting nutrients from the ocean back up the streams.  Many animals that ate these salmon (i.e. bears) directly benefited from the nutrients that salmon gained over months or years in the ocean.<ref>Salmon: Running the Gauntlet. Nature.  PBS. PBS Video, 2011.</ref>  Also, after spawning in the rivers, the salmon died and left their carcasses in the rivers. The rich nutrients within the salmon then decomposed and became a form of a natural fertilizer for the surrounding vegetation and even farm crops.<ref>Hymon, Steve. "Dead Salmon Give New Life to Rivers' Ecosystems: Fish Carcasses Return nutrients to Food Web." Mindfully.org | Mindfully Green. Los Angeles Times, 24 Mar. 2002. Web. 20 May 2011. <http://www.mindfully.org/Water/Dead-Salmon-New-Life24mar02.htm>.</ref> The creation of these dams therefore not only created a barrier for salmon reproduction but also stopped a vital transportation of nutrients up the stream where they were heavily relied on by many organisms.
-Though dams significantly reduce the amount of salmon that return to the Pacific from the Columbia, they also play a large role in the amount of clean energy produced by Washington State. Because of the amount of hydropower Washington State uses, it's carbon footprint is one of the lowest in the country.<ref>Daniel Huppert</ref> Though salmon are a great resource and dams often have many negative effects on their habitat, dams of the Columbia Basin are not all bad. Because there are a lot of stakeholders in the Columbia River Basin, extreme solutions will resolve the conflict between dam and salmon supporters. Instead, sacrifices need to be made by all parties. Some dams need to be modified to become more salmon-friendly and to increase stock diversity. Additional ladders and more spill water would help increase the salmon return. Also, salmon supporters have to realize that the dams provide clean energy. Completely destroying them involves a detailed plan of Adaptive Management that doesn’t move so fast that salmon resilience does not remain intact.<ref>Tom Leschine</ref>
-According to a study on the ecology of dam removal by Angela Bednarek a Ph.D.<ref>{{cite journal|last=Bednarek|first=Angela|title=The Ecology of Dam Removal|journal=American Rivers|url=http://www.michigandnr.com/PUBLICATIONS/PDFS/fishing/dams/EcologyofDamRemoval.pdf}}</ref>  candidate at the University of Pennsylvania, there may be some short-term negative impacts on river quality after dam removal, but the long-term impacts are extremely positive and generally result in a significant restoration in river processes and quality. Furthermore, through careful planning many negative short-term effects can be mitigated or reduced. The ecological benefits of removing the Snake River dams are quite obvious yet the controversy continues. According to an article by the Bonneville Power Administration,<ref>{{cite journal|title=Power Benefits of Lowers Snake River Dams|url=http://www.bpa.gov/corporate/pubs/fact_sheets/09fs/Fact_Sheet_-_Power_benefits_of_the_lower_Snake_River_dams.pdf}}</ref> the Snake River dams are an important source of clean energy for the region and they believe the benefits of clean energy far outweigh those of river restoration.
-While there are various issues that would arise with the four lower Snake River dams’ removal, there are many flaws in their current state.  The Lower Granite dam has been collecting sediment over the years and is currently 55% full.<ref>{{cite news
-|url= http://www.wildsalmon.org/index.php?option=com_content&view=article&id=348&Itemid=63##1
-|title=Why Remove The 4 Lower Snake River Dams?
-|work=Save Our Wild Salmon
-|publisher= Save Our Wild Salmon Coalition
-|accessdate=2011-05-18}}<!-- original URL: http://www.wildsalmon.org/index.php?option=com_content&view=article&id=348&Itemid=63##1 --></ref>  This occurrence is lowering the dam’s capacity to function efficiently while concurrently increasing the risk of flooding.  There are more effective methods to obtain energy, but as stated earlier, an immediate transition is improbable.  However, the dams have incurred a greater reliance on hatcheries as dam-caused mortality numbers have significantly offset the salmon run populations.  Unfortunately, those said hatcheries were unsuccessful in maintaining spawning runs and those within the Snake River Basin did far worse in comparison to hatcheries in other locations.<ref>{{cite news
-|url= http://faculty.washington.edu/huppert/SMAWorkingPaper-00-5.pdf
-|title=Columbia River Salmon Recovery: Where Are We Going? and How do We Get There?
-|publisher= Huppert PSU Symposium
-|accessdate=2011-05-18}}<!-- original URL: http://faculty.washington.edu/huppert/SMAWorkingPaper-00-5.pdf--></ref>  Factors such as these deter decisions from being made and keep the issue controversial.
-The four dams on the lower Snake River have been in place since 1975 <ref>(http://www.bluefish.org/fourdams.htm)</ref> and a great deal of controversy has always surrounded the implementation of these dams. The primary concern for those who oppose the dams is the drastic decline in salmon populations since the implementation of the dams. As Steven Hawley states in his article on the Columbia salmon plan, “Mortality for out-migrating juvenile salmon topped 90 percent for some Snake River fish".<ref>{{cite news| url=http://www.oregonlive.com/opinion/index.ssf/2010/03/what_dont_we_know_about_the_co.html | work=The Oregonian | title=What don't we know about the Columbia salmon plan? | date=2010-03-19}}</ref> Although many people in support of the Columbia salmon plan state that other factors such as climate change contribute the most to declining salmon populations, and that dam removal will not be an effective solution, in an article about the myths and facts of Lower Snake dam removal on the Save Our Wild Salmon website, it states: “In fact, the current federal salmon plan permits the federal dams to kill more than 90% of some of these salmon”.<ref>[http://www.wildsalmon.org/index.php?option=com_content&view=article&id=149&Itemid=63#Myth%206 Myths and Facts about Lower Snake River Dam Removal<!-- Bot generated title -->]</ref> Furthermore, in a study conducted by the U.S. Army Corps of Engineers, it was revealed that “the removal of the four lower Snake River dams would actually decrease total air emissions by seven tons per year from the transportation sector.” The Snake River Controversy is an ongoing conflict and it will not be resolved until a greater degree of transparency is reached by the government, and until biological and ecological values are placed above purely economic concerns.
 ==Tributaries==

v t e Columbia River
Provinces and states traversed	British Columbia Washington Oregon
Lists	Cities Crossings Dams Rapids Tributaries
Geology and geography	Geology of the Pacific Northwest Columbia River Basalt Group Columbia River Gorge Missoula Floods Bonneville Slide/Bridge of the Gods land bridge Columbia Mountains
Falls and rapids	Cascades Rapids Celilo Falls Kettle Falls Dalles des Morts
History	Robert Gray exploration Lewis and Clark Expedition David Thompson Pacific Fur Company Fort Vancouver Steamboats of the Columbia River Big Bend Gold Rush Steamboats of the Arrow Lakes Steamboats of the upper Columbia and Kootenay Rivers Columbia River Treaty Historic Columbia River Highway Columbia Basin Project Bonneville Power Administration Hanford Site Sohappy v. Smith Boldt Decision Vanport flood of 1948
Ecology and culture	Pacific salmon Roll On, Columbia, Roll On Confluence Project The Columbia River Collection