Preliminary work began in June 1953. The first step involved building infrastructures to deliver 500,000 tons of equipment, food and supplies to the 5,000 workers on site, including a wharf and a warehouse in Forestville and of roadwork in the hinterland. Everything, from sundries to cement, was shipped to Forestville, then unloaded at the Hydro-Québec wharf in Forestville and loaded into trucks for the trek to the interior. The 2-lane road from Forestville to Labrieville is now part of the
Quebec highway network and is now known as
Route 385.
Labrieville But even before starting work on the dam and power station, a stable supply of electricity was required. Hydro-Québec built a temporary hydroelectric plant at nearby Lac Cassé between November 1952 and July 1953. The 15,000-
horsepower (12 MW) hydroelectric generating station supplied the construction sites and camps. The equipment used for the temporary plant came from the Saint-Timothée generating station, a small hydro plant in the Montreal area dismantled by Hydro-Québec in 1949. Construction of Labrieville, a village named in honor of Napoléon-Alexandre Labrie, founding
bishop of the
Gulf of St. Lawrence Roman Catholic Diocese, began in June 1953. Besides temporary quarters for workers, an 8-classroom school, a 400-seat church, inn, an administrative and commercial center and 117 homes were built. The first tenant took possession of a dwelling on November 16, 1953, and the village was completed in 1955. Improvements in telecommunications and remote-controlled operations made it redundant, and the company chose to close Labrieville in 1974.
Dam The actual construction of the dams and power plant kicked off in October 1953. Two
rock-filled structures were built to create the
Pipmuacan Reservoir, increasing the surfaces of lakes Pipmuacan and Cassé: the first, long and high, is built between two mountains surrounding the Lac Cassé, the second, long, curtailed the release of water into the Desroches River. A mountain between the two dams was cut down to build a spillway for the reservoir. Both dams are similar in conception to the
Kenney Dam built in 1952 by
Alcan as part of their
Kemano,
British Columbia generating station.
Generating station The underground
powerhouse is located from the dam. A diameter, concrete-lined water intake was dug in the
Laurentian Plateau granite to bring water to a
manifold, where individual
penstocks feed the plant's 8 units. Work on the tunnel was carried out at an average speed of per week. The
surge tank has been carved from rock and is located from the first penstock. A shaft rises vertically , connects to the bottom of the surge tank, in diameter and deep, and opens on to a hilltop overlooking the village. The powerhouse was carved inside the mountain and is accessed through a tunnel. Inside the long, high and wide cavity were installed eight 150,000-
horsepower Francis turbines, connected to 13.8 kilovolt generators. Parallel to the powerhouse, a
tailrace tunnel discharges the water to the river channel below.
Power lines Construction of the 2 double-circuit
high voltage overhead power lines built to carry power to Quebec City and Montreal attracted considerable interest in the engineering
trade press and contributed to raise the profile of Hydro-Québec's engineers internationally. From the power station, the 315-kilovolt (kV) power lines, among the first to be built in North America at this voltage, follow a westerly direction to reach the Sault-aux-Cochons River, where they turn south following the valley. Near the mouth of the river, the line takes a south-westerly orientation, parallel to the Saint Lawrence River and crosses the
Saguenay River fjord near
Petit-Saguenay. Two sets of
crossing pylons, separated by a
span width of were built on each side of river in order not to interfere with shipping. A third 315 kV power line to
Baie-Comeau was built to bring power to the
Gaspé Peninsula, via 4-
submarine power cables, linking the Manicouagan peninsula to the Les Boules substation in
Métis-sur-Mer. Laying the cables at a depth of proved difficult, due to high winds and heavy waves, damaging two cables. A first attempt to power the cables was made in December 1954, but they became operational in November 1955, almost a year later. Starting in 1959, corrosion and the action of ice caused repeated failures leading to its decommissioning in 1962.
Working conditions Allegation of mistreatment of workers on the worksite stirred controversy in early 1954. Reporter
Pierre Laporte published a six-part series in Montreal's
Le Devoir on the construction of Bersimis-1 in January 1954. In his stories, Laporte reports on the long hours, bad pay and unhealthy working conditions, mismanagement and shady contracting practices. The stories, published a few days after 10 men died in a scaffolding collapse on January 22, 1954, generated heated debates at the
Legislature. Inspired by Laporte's reporting,
Liberal opposition leader
Georges-Émile Lapalme accused the
Maurice Duplessis government of mismanagement. In a history
M.A. thesis submitted in 2009, Richard Landry concluded that pay and working conditions onsite were comparable or even better than what was afforded to the average Canadian worker at the time, while stressing the 1954 accident incited Hydro-Québec to implement health and safety measures geared towards prevention. ==Operations and maintenance==