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sh. The Snake and its tributary, the Salmon River, host the longest sockeye salmon run in the world, stretching 900 miles (1,400 km) from the Pacific to Redfish Lake in Idaho. Since the 1950s, public agencies, tribal governments and private utilities have invested heavily in fishery restoration and hatchery programs, with limited success.
As gold mining declined in the late 19th century, the wheat industry boomed in the Palouse of southeast Washington. By the 1870s, the Oregon Steam Navigation Company was operating seven steamboats transporting grain from the Snake River to lower Columbia River ports. These were the Harvest Queen, John Gates, Spokane, Annie Faxon, Mountain Queen, R.R. Thompson, and Wide West. In the 1890s, a huge copper deposit was discovered at Eureka Bar in Hells Canyon. Several ships transported ore from there to Lewiston, including Imnaha, Mountain Gem, and Norma. In 1893 the Annie Faxon suffered a boiler explosion and sank on the Snake below Lewiston, killing five people. Starting in the 1880s, the Army Corps began dredging the Snake River below Lewiston to maintain a 5-foot (1.5 m) deep navigation channel.
River traffic declined rapidly once railroads arrived. By 1899, the Union Pacific line along the south bank of the Snake River had reached Riparia, Washington. It then joined forces with the Northern Pacific Railroad, which was building a line along the north bank, to build the shared Camas Prairie Railroad the rest of the way to Lewiston, which it reached in 1908. The Open River Transportation Company, which operated steamboats between Lewiston and Celilo Falls on the Columbia, went bankrupt in 1912. The 1915 completion of the Celilo Canal made it much easier for boats from the upper Columbia and Snake to reach Portland, and the Columbia River Transportation Company began operating a water route between Lewiston and Portland. Still, steamboats were unable to compete with railroads on speed and efficiency. The last steamboat on the lower Snake ran in 1920.
Once the railroads monopolized grain shipments, they raised shipping rates, to farmers' consternation. In 1934, political activist Herbert G. West organized the Inland Empire Waterways Association (IEWA), to promote an "open river" – a deep-water shipping channel on the Snake and Columbia Rivers that could compete with rail. The IEWA initially pushed for improvements such as bigger locks at Bonneville Dam in 1938 and the construction of McNary Dam on the Columbia, which would improve navigation to the mouth of the Snake. In 1941 a bill was first introduced in Congress authorizing the Army Corps to develop the lower Snake River. The 1941 bill failed, but after several years of debate, Congress finally authorized the Snake River development in 1945. Early plans included anywhere from six to ten low dams for the lower Snake. Eventually this was reduced to four bigger dams, which would lower costs, but would require what at the time were the tallest navigation locks in the world, at over 100 feet (30 m).
Tribes, state wildlife agencies and the fishing industry opposed the dams, arguing that they would kill too many salmon. In 1947, the U.S. Department of the Interior proposed a ten-year moratorium on dam construction while the fishery problem was studied. With the onset of the Cold War, rising electricity demand in the Pacific Northwest – particularly at the nearby Hanford nuclear site – turned the project's focus towards hydropower. By 1948, the Army Corps estimated that over 80 percent of the economic benefits would come from power, and only 15 percent from navigation. Dam opponents countered that if the primary objective was now power, other dam sites existed in the Northwest that would have less impact on fish. These objections proved futile, as the lower Snake River dams were already authorized, and the federal government had little interest in studying alternatives. While opponents continued to stall the project for a few more years, Washington Senator Warren G.
Populations of anadromous fish began to decline in the late 1800s due to the impact of commercial fishing, logging, mining and agriculture, but even in the 1930s, returning fall chinook alone numbered 500,000. Populations further collapsed once dams were built on the lower Snake and Columbia Rivers, and Hells Canyon Dam blocked access to the upper Snake. Wild Snake River spring and summer chinook returns declined from 130,000 in the 1950s to less than 5,000 in the 1990s. Wild steelhead returns followed a similar pattern, falling from 110,000 in the 1960s to less than 10,000 in the 1990s. Spring, summer and fall-run chinook were all listed as threatened in 1992. Snake River steelhead were also listed as threatened in 1997.
Wild chinook salmon and steelhead continued to decline into the 1990s, but have begun an unsteady recovery since 2000, with both chinook and steelhead returns up to 20,000–30,000 in some years. Coho salmon had disappeared from the Snake River by the 1980s, they were reintroduced to the watershed in 1995.
Snake River sockeye once numbered to up 150,000 adults. Between 24,000 and 30,000 sockeye returned to Wallowa Lake in the Grande Ronde River watershed, but the run was eliminated by 1905 due to overharvest and unscreened irrigation diversions. The Payette Lake population once numbering up to 100,000 was blocked by the Black Canyon Dam in 1924. Sockeye in the Yellowbelly, Stanley, and Pettit Lakes of the Sawtooth basin were eradicated by management actions of the Idaho Department of Fish and Game in the 1950s, and irrigation diversions lead to the extirpation of the Pettit Lake population. Snake River sockeye returns declined to 4,500 in the 1950s and only a few dozen by the late 1960s. Snake River sockeye were listed as endangered in 1991.
Numerous hatcheries are operated by agencies such as the Army Corps, Idaho Power, the Bonneville Power Administration, the U.S. Bureau of Indian Affairs and the U.S. Fish and Wildlife Service, to supplement wild fish populations. Hatcheries release about 33 million salmon and steelhead smolt into the Snake River watershed each year. However, the survival rate for hatchery fish is poor. Just 0.4 percent of hatchery chinook and 1.5 percent of hatchery steelhead returned as adults, as measured at Lower Granite Dam between 2007 and 2016.
Upstream of the four lower dams, the Snake River watershed contains some of the best remaining spawning habitat in the Columbia River system, particularly along the Clearwater and Salmon Rivers; the latter is one of the longest undammed rivers in the continental US. A much depleted sockeye salmon run continues to spawn in Redfish Lake near Stanley, Idaho, more than 900 miles (1,400 km) inland from the Pacific Ocean.