Lake Athabasca

Lake Athabasca is a massive freshwater lake located in Canada.

It sits in the north-west corner of Saskatchewan and the north-east corner of Alberta. The lake is divided between these two provinces. About 74% of the lake is in Saskatchewan. The remaining 26% is in Alberta. It is the largest lake in both provinces. It is also the eighth largest lake in Canada and the 20th largest lake in the world by area.

The lake functions as a central part of a large drainage system. Many rivers act as tributaries by flowing into the lake. These include the Athabasca River, the Fond du Lac River, and the Peace River. The water follows a specific path as it leaves the lake. It flows northward through the Slave River. From there, it enters the Mackenzie River system. Eventually, this water reaches the Arctic Ocean.

Geologically, Lake Athabasca is a remnant of a much larger ancient body of water. This ancient body was called Glacial Lake McConnell. The lake is long and reaches a maximum depth of 64 meters. It holds about 5,220 cubic kilometers of water. The lake's shape changes as you move across it. The eastern section narrows significantly near the community of Fond du Lac. This area is on the northern shore. The lake reaches its most easterly point at the mouth of the Fond du Lac River.

Indigenous peoples have lived in this region for more than 2,000 years. The name for the lake comes from the Woods Cree language. In Cree syllabics, the name means "where there are plants one after another." This name originally described the Peace–Athabasca Delta. This delta forms where the Peace and Athabasca rivers meet at the southwest corner. European explorers arrived much later. Sir Alexander Mackenzie explored the lake before 1789. In 1791, a cartographer named Philip Turnor described the area as low, swampy ground with willow trees.

The history of the lake is tied to the North American fur trade. During this era, the lake was a vital location for travelers. It was the furthest west that canoes could travel from the east. This was because travelers needed to return before the water froze. The North West Company founded Fort Chipewyan in 1788. This is one of the oldest European settlements in Alberta. It was originally located at Old Fort Point. In 1798, the settlement moved to its current site on the north shore. Other groups like the Hudson's Bay Company also tried to establish posts nearby. They built Nottingham House on English Island in 1802. They also built Fort Wedderburn on Coal or Potato Island in 1815.

Lake Athabasca supports a diverse biological environment. There are 23 different species of fish living in its waters. These include walleye, northern pike, and Arctic grayling. In 1961, a world record lake trout was caught here using a gillnet. Near the southern shore in Saskatchewan, there are also large sand dunes. These are the Lake Athabasca Sand Dunes. They are the largest active sand dunes in the world north of 58 degrees latitude. In 1992, they were designated as a Provincial Wilderness Park.

Human industrial activity has changed the environment around the lake. Uranium and gold mining occurred along the northern shore. This mining led to the creation of Uranium City in Saskatchewan. While the mines closed in the 1980s, they caused heavy contamination on the northern shores. Large oil sands mining nearby is also suspected to have added to pollution levels. In October 2013, a coal mine pit at Obed Mountain failed. This caused between 600 million and one billion litres of slurry to pour into local creeks. This waste traveled downstream for a month. It finally settled in Lake Athabasca near Fort Chipewyan, over 100 kilometers away.