Hells Gate is an abrupt narrowing of British Columbia's Fraser River, located immediately downstream of Boston Bar in the southern Fraser Canyon. The towering rock walls of the Fraser River plunge toward each other forcing the waters through a passage only wide. It is also the name of the rural locality at the same location.

For centuries, the narrow passage has been a popular fishing ground for Aboriginal communities in the area. European settlers also began to congregate there in the summer months to fish. Eventually, the Fraser Canyon became a route used by gold rush miners wishing to access the upper Fraser gold-bearing bars and the upper country beyond up the Fraser and the Thompson. In the 1880s the Canadian Pacific Railway (CPR) built a transcontinental railway that passed along the bank at Hell's Gate, and in 1911 the Canadian Northern Railway (CNoR) began constructing a second track. In 1914 a large rockslide triggered by CNoR construction fell into the river at Hells Gate, obstructing the passage of Pacific salmon needing to swim upstream to spawn. Salmon had difficulty passing through the now swifter water, and were appearing in increased numbers downstream below the Hells Gate passage and in tributary rivers and streams that they had not inhabited before. In the winter of 1914 debris removal began, and in 1915 the river was pronounced clear. However many biologists claim that the river was permanently altered and the salmon migration would forever remain disturbed by the slide.

A decrease in Fraser salmon catalyzed tension between the Government of Canada and the Aboriginal peoples of the area. Not only did the debris clearing operation impede their access to the river, but the government imposed new fishing restrictions, such as a four-day-per-week limit, in an attempt to preserve the salmon population. Ultimately the slide and subsequent restrictions proved very damaging for the Aboriginal fishing economy.

The Canadian and United States governments formed the Pacific Salmon Convention (PSC) of 1937, which created the International Pacific Salmon Fisheries Commission (IPSFC) (now the Pacific Salmon Commission). The IPSFC carried out extensive research, and as based on their findings they recommended that fishways be constructed to help migrating salmon pass through Hells Gate. Building of the fishways began in 1944.

This decision sparked a major controversy in the Pacific fisheries and research community, which became divided along national lines. American William Thompson, head researcher for the IPSFC, was criticized by Canadian zoologist William Ricker who claimed that the IPSFC research was unreliable and that fishways were not a means to preserving Fraser salmon. Ricker believed that Hells Gate posed no threat to migrating salmon, and that commercial over-fishing did. He held that stringent regulations should be placed on fishing for Fraser salmon.

The fishways at Hells Gate became a tourist attraction in the 1970s. Among the attractions for tourists are the airtram, food outlets, observation decks and an educational fisheries exhibit.

History The name Hells Gate was derived from the journal of explorer Simon Fraser, who in 1808 described this narrow passage as "a place where no human should venture, for surely these are the gates of Hell." Long before the arrival of Simon Fraser, and as early as the end of the last ice age, Hells Gate was a First Nations congregation ground for settlement and salmon fishing. Archaeological evidence from old occupation sites and isotope analysis of human skeletal remains suggest that settlement and migration patterns for indigenous peoples in the Canyon correlated with the seasonal migration patterns of Pacific salmon. During the last deglaciation 4000–6000 years ago, long tongues of ice formed wedges and dams in the river's basin above the canyon, resulting in the formation of large reservoirs and new lakes—creating optimal spawning grounds for salmon. During this inter-glacial period, salmon began to populate the Fraser River and used Hells Gate passage as their route to upstream spawning grounds. Constricted by two steep subvertical granodiorite walls, the incredibly narrow passage and high water velocity made this part of the upstream journey extraordinarily difficult for salmon, and they would hover along the shores of the river or rest in its back-eddies. As a result, Hells Gate’s geology provided the Indigenous fishers with superb opportunities to readily catch salmon congregated at the river’s edge attempting to elude the strong currents and rough waters. Hells Gate became one of the most popular fishing stations along the Fraser River— pre- and post-colonial contact— where large numbers of aboriginal locals, and eventually European settlers, congregated during the summer months to fish for migrating salmon. Standing on adjacent rocks or on specially constructed wooden platforms extending from surrounding cliffs, fishermen would use long dip nets to snatch the salmon. Salmon fishing at Hells Gate was so prolific that, as Matthew Evenden asserts, the aboriginal culture along the Fraser River was built on a "salmon economy." After Simon Fraser charted the river in the early nineteenth century, it became (and Hells Gate with it) an established corridor between the Pacific Ocean and the interior of what was to become British Columbia. Yet, as Fraser first noted, safe water transportation through the 115 foot wide opening at Hells Gate has proven virtually impossible.

Hells Gate slide

By the 1850s the Fraser Canyon was transformed from a First Nations and fur trade corridor to a busy route, called the Cariboo Road, used by gold rush miners seeking access to the upper Fraser Basin. During the 1880s, the Canadian Pacific Railway built a new transcontinental railroad to unite the far-flung provinces of the young Dominion of Canada. This nation-building project saw new railroad tracks constructed on the west riverbank at Hells Gate, connecting the British Columbia coast to the Interior (and the rest of Canada) through the Fraser Canyon. Some assert that rocks and debris dumped into the river during construction of the CPR constricted the river flow and impeded salmon passage, though there is no documented historical or physical evidence to support this claim. By early 1911 the Canadian Northern Railway began a second transcontinental railway along the south and east bank of the canyon, which was completed in a year's time. While carving into canyon walls to create new rail-bed, rock and debris were again dumped into the river in significant volumes at various locations, including Hells Gate. In early 1914, two years after the completion of the CNoR and during construction of a new tunnel, a large rockslide fell into the river just above the Hells Gate portal. Debris dispersed on the river bottom caused a 5-meter vertical drop in water depth and increased water velocity from five metres per second to 6.75 metres per second. As observed and noted by local residents and later by biologists in the aftermath of the slide, noticeably higher water velocity seemed to exceed the swimming capacity of the salmon, resulting in premature mortality and reduced populations of salmon fry in the subsequent year. In an initial attempt to redress the ecological and physical changes at Hells Gate that impeded migrating salmon, tons of rocks and debris were removed from the river during the winter of 1914-1915. By early 1915, Hells Gate was pronounced clear. While government officials declared that the river at Hells Gate was fully restored, many biologists maintain that the slide permanently altered the river's ecology.

Environmental impacts on salmon

Short term Environmental change triggered by the slide at Hells Gate has led to habitat destruction and depletion of salmon species. The slide altered the environment of the river by increasing turbulence and density, and salmon's ability to swim upstream was seriously disrupted as many fish, exhausted by the journey through Hells Gate, were carried back downstream. Daily alterations of water levels also hindered passage of some fish species, and Evenden even goes so far as to equate the slide to "an enormous dam". The slide's impacts became visible by the decreasing amount of salmon upriver and the constant fish supply below led to alternating cycles of salmon’s expansion and decline, with runs coming at the beginning of the seasons faring better in the changed environment than the later runs, which experienced a more significant decline. Unable to swim upriver, salmon relocated into rivers and tributary streams that were not previously used by them, and increased fish concentration spanned up to several kilometers below the Hells Gate passage. Pink salmon have taken greater environmental toll than sockeye, as the pinks are of a smaller size and therefore, weaker swimmers than the sockeye. Salmon were forced to spawn in new places and many died without spawning or did not produce many offspring as the habitat was "unsuitable." Changes in "racial units" upstream, accounted for the majority of salmon population, were traced back to Hells Gate obstruction. As well, the majority of the salmon that did not get through the passage were females (in Spuzzum Creek the male to female ratio was 1:20). Ultimately, in the short term, salmon population declined.

Long term Slide-triggered environmental changes that threaten salmon in the short term can be disastrous in the long run, as a "year's run once eliminated does not return." Decline in salmon was noticeable for about 14 years after the slide occurred. Pacific salmon have a unique four-year cycle, with some years being "big" and some "small"; 1913 was a "big" year, and 1917 should have been as well. However the salmon numbers were especially low in 1917, which signalled changes in the "original cycle." 1913 was estimated to produce 2,401,488 salmon, while 1917 estimates were substantially lower, at 559,702 salmon. By the mid-20th century the slide had destroyed a significant amount of salmon from the Upper Adams River, where restoration efforts had limited success. Salmon depletion was perceived by Babcock as possibly leading to "extermination" of the salmon in the region. Studies done in 1941 mentioned that Hells Gate inhibited salmon passage, where salmon clustering below the passage matured into spawning sockeye. After the fishways were installed the sockeye numbers increased, and pink salmon numbers upriver rebounded. Ultimately salmon "homing tendency is remarkably strong," therefore many sockeye easily fall victim to human triggered changes of the environment.

Social and political impacts