The Bridge River Power Project is a hydroelectric power development in the Canadian province of British Columbia, located in the Lillooet Country between Whistler and Lillooet. It harnesses the power of the Bridge River, a tributary of the Fraser, by diverting it through a mountainside to the separate drainage basin of Seton Lake, utilizing a system of three dams, four powerhouses and a canal.
The potential for the project was first observed in 1912 by Geoffrey Downton, a land surveyor, visiting the goldfield towns in the area who noticed the short horizontal distance between the flow of the Bridge River, just above its impressive canyon, and the much-lower Seton Lake. It was fifteen years before this observation was put to task, and not until 1927 that a private company first bored a tunnel through Mission Ridge (also known as Mission Mountain), which separates the basins of the Bridge and Seton systems. This tunnel was completed in 1931, but work on the project was suspended due to the Great Depression and the Second World War. Construction of a powerhouse to utilize the diversion did not begin until 1946.
A townsite, or employees village, was built in the 1920s adjacent to the construction site. It was developed as a model community, with a community hall, a combined rink and tennis court, lavish guest houses for visiting executives, parks, a school, a private beach and a full-service hotel which served the busy travel trade over the mountain to the goldfields towns of Bralorne, Pioneer and Minto. Mostly abandoned during the 1930s, the townsite - known as "Bridge River" (although not actually on that river) - was used during the war as a relocation centre for Japanese-Canadians exiled from the Coast in the wake of the Japanese attack on Pearl Harbor. Its most notable resident during that period was Masajiro Miyazaki, an osteopath who was engaged by the provincial police in Lillooet to serve as coroner despite wartime restrictions, and stayed on as the town doctor for years after. Miyazaki was conferred an Order of Canada award for his service to that community.
Following the war, growing power requirements led to a fast-tracking of the project, which was the largest at the time and one of the most staggering ever undertaken because of the terrain and spectacular setting of the project. Materials for the diversion dams in the Bridge River and all equipment for the powerhouse to be built at Lajoie, near Gold Bridge, had to be trucked over the 3,500-foot (1,100 m) climb and dozens of switchbacks of the tortuous Mission Mountain Road, which was also shared with industrial and passenger traffic to and from the busy mine towns. The only access to the railhead for that road, at Shalalth, was via the rail line itself from Lillooet and, to get there, via the old pre-Trans-Canada "Cariboo Highway" from Hope to Lytton that had not been upgraded much since it was built in the 1920s.
The first generator was installed at what would become Bridge River Powerhouse No. 1 in 1948, with three more generators added by 1954, giving the plant a total output of 180,000 kilowatts - easily the largest in the province at that time. A second tunnel, with two large penstocks, was built to supply a second powerhouse on the far side of the townsite. Work on this powerhouse (called No. 2) was carried out while the tunnel that would supply it was being bored, and it would have four generators, officially opening in 1960 with a generating capacity of 248,000 kilowatts. Geoffrey Downton, the "discoverer" of the project, was invited to push the "start" button to fire up the No. 2 generators.
The No. 1 Powerhouse is fed by four penstocks, the No. 2 Powerhouse by two much larger ones, which supply the water from Carpenter Lake, created by Terzaghi Dam, from the tunnels bored through Mission Mountain. Terzaghi Dam was immediately above the pass, just below the tunnel intakes and Mission Creek, which is the valley on the north side of the pass. It was often known as Mission Dam before being officially named Terzaghi Dam, after Karl Terzaghi, the "father of modern soil mechanics" who was the chief consultant. Another dam, Lajoie Dam, three kilometres above the gold-mining district's supply town of Gold Bridge, was built at Lajoie, 60 kilometres above the diversion dam. Construction of Lajoie Dam began in 1949 as a simple storage dam to regulate reservoir levels for the Bridge River plants, but in 1955 it was raised to its full height of 287 feet (87 m), creating Downton Lake, 534,300 acree-feet of water, elev. 2,460 feet (750 m). A one-generator powerhouse was completed in 1957 with a capacity of 22,000 kilowatts, much of that destined to feed the power demands of the Bralorne and Pioneer Mines and their associated towns, only ten miles away, as well as other residents and towns elsewhere in the upper Bridge River valley.
Terzaghi Dam, lower in crest than Lajoie Dam at 180 feet (55 m) but also the most important structure in the project, was completed in 1960, creating Carpenter Lake. It replaced an earlier structure, a cofferdam, which had been built across the Bridge River to force its flow into the Powerhouse No. 1 diversion tunnel, which was open and operating in 1948. The rising lake waters flooded out several large ranches and homesteads in the valley, some of which dated back to the 1890s, and also the short-lived company town of Minto City, which lay at the confluence of Gun Creek with the former Bridge River, despite a long holdout by Wally O'Keeffe; owner of the Rexmount Ranch and his attempts to rally the people of Minto against the project.
Seton Lake existed before the project, but a small diversion dam at its outlet raised the level of the lake by about 10 feet (3.0 m). From the lake's outlet, a specially built canal carries the diverted flow of the Bridge River to the last possible bit of "head" before the Fraser River, a differential of only 140' but enough to generate 42,000 kilowatts. The canal, known as Seton Canal, is highly unusual in that it bridges both Seton and Cayoosh Creeks before being briefly tunneled through a low rock bluff to the Seton Powerhouse, which is right on the Fraser River just below the town of Lillooet.
The British Columbia Electric Company, successor to the Bridge River Power Company on this project and the main electrical utility in the province, was taken over and nationalized by the British Columbia government in 1961 and became the larger part of BC Hydro and Power Authority, a Crown Corporation.
A full official assessment of this project's impact on the local and provincial environment has never been completed, and was not required at the time of its construction. Seton Lake, once pristine and renowned for its crystalline sky-blue colour, was turned cold and opaque by the diverted waters of the Bridge River, which are glacial and milky-green in colour.
Damage to the fishery on both river systems involved was incalculable.[ citation needed ] Although a fish ladder was built at the Seton diversion, it is generally conceded that the project virtually wiped out the entire Bridge River salmon runs, once one of the river's largest and most important and, in so doing, caused a local famine among the area's populous fishery-dependent native bands.[ citation needed ] It was hoped that the returning Bridge River salmon would follow the smell of Bridge River water up the Seton-Cayoosh system, where a fish ladder and also a set of hatchery channels were constructed, but the fish attempted to swim directly into the tailrace of the Lillooet Powerhouse. To ameliorate this, a tunnel was bored through the moraine at the foot of Seton Lake to feed water from Cayoosh Creek into the lake near the diversion, so that the mix of waters coming out of Cayoosh Creek's confluence with the Fraser would confuse the fish and some of them would choose the creek instead, thereby finding the hatchery. This was of mixed success, and as far as many locals concerned only served to make the water at the public beach at the foot of Seton Lake colder than it already was.
Unscheduled releases of water from Terzaghi Dam during spawning seasons in the 1990s caused a furor amongst local residents and First Nations, with a major investigation launched and Hydro now operating under strict rules for releasing water.[ citation needed ]
The most immediate and visible environmental impact of the project, however, was the inundation of the upper Bridge River Valley. Formerly a serpentine flat-bottomed valley framed by its tributary canyons and ranges, the valley had been home to a number of prospectors, settlers, lodges and others who were forced from their homes by the rising waters of Carpenter Lake, which also drowned what was left of Minto City (there were no residents in the area of what is now Downton Lake). Acrimony over the evictions continued for many years, and feelings from old-timers about the fate of their valley remain strong among their offspring.[ citation needed ] Much of Carpenter Lake today is mudflat when reservoir levels are low, and for many years it was a stark reminder of older environmental standards, with vast forests of dead trees sticking out of the frigid, milky-blue glacial waters. Some[ who? ] feel that the shift in temperature regimes in the two river basins affected local climate patterns, with the upper valley now more moderate in climate and the Seton valley considerably cooler.
Programs in the 1980s to engage prisoners and others in the removal of these trees were launched during low-water levels, and the lake today is largely safe for boating, and while stocked for fishing it is still inadvisable for swimming due to its icy-cold water.
The Fraser Canyon is a major landform of the Fraser River where it descends rapidly through narrow rock gorges in the Coast Mountains en route from the Interior Plateau of British Columbia to the Fraser Valley. Colloquially, the term "Fraser Canyon" is often used to include the Thompson Canyon from Lytton to Ashcroft, since they form the same highway route which most people are familiar with, although it is actually reckoned to begin above Williams Lake, British Columbia at Soda Creek Canyon near the town of the same name.
Shalalth, pop. c. 400, is one of the main communities of the Seton Lake Band of the St'at'imc (Lillooet) Nation and location of the two main powerhouses of the Bridge River Power Project.
The Bridge River is an approximately 120 kilometres (75 mi) long river in southern British Columbia. It flows south-east from the Coast Mountains. Until 1961, it was a major tributary of the Fraser River, entering that stream about six miles upstream from the town of Lillooet; its flow, however, was near-completely diverted into Seton Lake with the completion of the Bridge River Power Project, with the water now entering the Fraser just south of Lillooet as a result.
The Lillooet Ranges are the southeasternmost subdivision of the Pacific Ranges of the Coast Mountains of British Columbia. They are located between the drainage of the Lillooet River and Harrison Lake on the west and the canyon of the Fraser River on the east, and by the lowland coastal valley of that river on the south.
Seton Lake is a freshwater fjord draining east via the Seton River into the Fraser River at the town of Lillooet, about 22 km (14 mi) long, 26.2 km2 (10.1 sq mi) in area and lies at an elevation of 243 m (797 ft). Its depth is 460 m (1,500 ft).
The Cayoosh Range is the northernmost section of the Lillooet Ranges, which are a subrange of the Pacific Ranges of the Coast Mountains in British Columbia, Canada. The range covers an area of c. 3770 km² and is approximately 65 km (40 mi) SW to NE and about 20 km (12 mi) SE to NW.
Terzaghi Dam is the key diversion dam in BC Hydro's Bridge River Power Project. It forms the project's largest reservoir, Carpenter Lake west of Lillooet. Originally known as the Mission Dam, it was renamed Terzaghi Dam in 1965 to honor Karl von Terzaghi, the civil engineer who founded the science of soil mechanics. It is located about 30 km up the Bridge River from its confluence with the Fraser.
N'Quatqua, variously spelled Nequatque, N'quat'qua, is the proper historic name in the St'at'imcets language for the First Nations village of the Stl'atl'imx people of the community of D'Arcy, which is at the upper end of Anderson Lake about 35 miles southeast of Lillooet and about the same distance from Pemberton. The usage is synonymous with Nequatque Indian Reserve No. 1, which is 177 ha. in size and located adjacent to the mouth of the Gates River.
Lajoie Dam is the uppermost of the storage dams of BC Hydro's Bridge River Power Project, which is located in the southwestern Interior of British Columbia. It is located just west of the small semi-ghost town of Gold Bridge. An earthfill structure, it is 87 m and impounds c. 570,000 acre feet (700,000,000 m3) of water in Downton Lake Reservoir. The Lajoie Powerhouse generates 22 MW with an average generating capacity of 170 GWh/year. A few miles downstream is Carpenter Lake, which is formed by Terzaghi Dam, the largest of the Bridge River Power Project's structures.
Carpenter Lake, officially Carpenter Lake Reservoir, is the largest of the three reservoirs of the Bridge River Power Project, which is located in the mountains west of Lillooet, British Columbia. The lake is about 185 kilometres north of the province's major city of Vancouver and is formed by the 1951 diversion of the Bridge River by Terzaghi Dam into Seton Lake via a tunnel through Mission Mountain, which separates the Seton and Bridge drainages. Several ranches and homesteads in the broad serpentine of the upper Bridge River basin were flooded out by the hydro project, which changed the character of the upper valley forever.
Seton may refer to:
Mount Downton is the highest summit of the 10 km (6 mi) diameter Itcha Range, located 40 km (25 mi) northeast of Anahim Lake and 33 km (21 mi) east of Far Mountain in the Chilcotin District of the Central Interior of British Columbia, Canada. It lies within Itcha Ilgachuz Provincial Park.
The Seton River is a tributary of the Fraser River in the Canadian province of British Columbia. The name is relatively new, and encompasses what had formerly been the Seton Portage River or Portage Creek and Seton Creek.
The Seton Powerhouse is a hydroelectric generating station on the Fraser River just below the confluence of the Seton River at the town of Lillooet, British Columbia, Canada. The powerhouse is fed by the Seton Canal, a 5 km diversion of the flow of the Seton River which begins at Seton Dam, just below the foot of Seton Lake to the west. The powerhouse is the last in sequence, and smallest, of the generating stations of BC Hydro's Bridge River Power Project, which diverts the flow of the Bridge River into Seton Lake. The powerhouse uses only 50 feet of head between Seton Lake and the Fraser to produce a maximum generating capacity of 42 MW and an average capacity of 330 GWh per year.
The Seton Canal is a diversion of the flow of the Seton River from Seton Dam, just below the flow of Seton Lake, to the Seton Powerhouse on the Fraser River at the town of Lillooet, British Columbia, Canada. The canal bridges Cayoosh Creek 300m below its commencement and is about 3.5 km in length, ending just below a bridge used by the Texas Creek Road, where the canal's waterflow is fed into tunnels which feed the Seton Powerhouse on the farther side of a small rocky hill. Most of the water carried by the canal is the volume of the diverted Bridge River, which is fed into Seton Lake via BC Hydro's Bridge River generating stations at Shalalth, 16 km to the west, which are supplied by diversion tunnels through Mission Ridge from Carpenter Lake, the reservoir created by Terzaghi Dam.
Cayoosh Creek is a northeast-flowing tributary of the Seton River in the Canadian province of British Columbia. The name Cayoosh Creek remains on the bridge-sign crossing the stream on BC Highway 99 and continues in use locally to refer to the final reaches of the Seton River, formerly Seton Creek, which prior to the renaming ending at the confluence with Cayoosh Creek. The creek is the namesake of Cayoosh Creek Indian Reserve No. 1, one of the main Indian reserves of the Cayoose Creek Indian Band, which lies adjacent to what was renamed the Seton River without local consultation.
Downton Lake, originally Downton Reservoir, and also known as Downton Lake Reservoir, is a reservoir in the Bridge River Country of the Interior of British Columbia, Canada, formed by Lajoie Dam, the uppermost of the series of dams and diversions of the Bridge River Power Project.
Mission Ridge, also known as Mission Mountain, is a ridge in the Bridge River-Lillooet Country of the South-Central Interior of British Columbia, Canada, extending westward from the town of Lillooet along the north side of Seton Lake to Mission Pass, which is immediately above and to the north of the lakeside community of Shalalth. The road over the pass is also known as Mission Mountain, which is short for "Mission Mountain Road". Mission Creek lies on the north side of the pass, and is a tributary of the Bridge River, the lower reaches of which lie on the north side of the ridge, and which was the only road access into the upper Bridge River Country before the construction of a road through the Bridge River Canyon in the mid-1950s opened that region up to road access from the lower Bridge River valley and the town of Lillooet via the community or Moha. Most, or virtually all, of the ridge, is Indian Reserves, notably Slosh 1, under the administration of the Seton Lake Indian Band, and Bridge River 1, which is under the administration of the Bridge River Indian Band. Parts of the ridge's eastern end are in reserves controlled by the Lillooet Indian Band, including its final spires above Lillooet, which were dubbed St. Mary's Mount by the Reverend Lundin Brown in the 1860s, though that name never stuck and is ungazetted.
The Bridge River Rapids, also known as the Six Mile Rapids, the Lower Fountain, the Bridge River Fishing Grounds, and in the St'at'imcets language as Sat' or Setl, is a set of rapids on the Fraser River, located in the central Fraser Canyon at the mouth of the Bridge River six miles north of the confluence of Cayoosh Creek with the Fraser and on the northern outskirts of the District of Lillooet, British Columbia, Canada.
