A massive Canadian reservoir held back by eighty-eight separate dikes instead of one

Countries & Cities · Published 29 September 2026 Swipe more like this →

In short: The Smallwood Reservoir in Labrador is a feat of engineering that defies the conventional image of a dam. Rather than relying on a single massive wall, this vast body of water is contained by a sprawling network of eighty-eight dikes, creating the fifth-largest reservoir on the planet by surface area.

Located on the saucer-shaped Labrador Plateau, the Smallwood Reservoir serves as the primary water source for the Churchill Falls Generating Station. Before its creation, the region was a complex landscape of interconnected lakes and bogs, including the large bodies of water known as Ossokmanuan, Lobstick, and Michikamau. The project, which officially began in 1967, required the construction of a complex system of control structures and dikes to manage the flow of the Churchill River across this high-altitude terrain, which sits between 457 and 579 meters above sea level.

The scale of the undertaking was immense, requiring nine years of labor between 1966 and 1974. At the height of construction in 1970, over 6,000 workers were stationed across a main camp and eleven satellite sites. Despite the logistical challenges of working in such a remote environment, the project was finished five months ahead of schedule. The reservoir itself covers 6,527 square kilometers, making it the largest freshwater body in the province of Newfoundland and Labrador.

The engineering design was not always considered feasible. An initial evaluation conducted in 1942 by the H.G. Acres Company for the Aluminum Company of Canada deemed the site too remote and expensive to develop. It was only with advancements in long-distance electricity transmission that the project became viable. Today, the reservoir is managed through three primary control structures—Gabbro, Lobstick, and Whitefish—along with spillways designed to prevent flooding, ensuring the stability of the massive, multi-dike containment system.

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