Mackenzie River basins, mostly in Alberta. The cold northern permafrost regions beyond the Arctic Circle are very sparsely populated, mainly by indigenous peoples. Most of the Mackenzie watershed is unbroken wilderness and human activities have little influence on the overall water quality, although there are some localized impacts. Some parts of the Mackenzie basin are rich in natural resources – oil and gas in the Northwest Territories and in central Alberta, lumber in the Peace River headwaters, uranium in Saskatchewan, gold and zinc in the Great Slave Lake area and tungsten in the Yukon. As of 2003 there were two operational gold
Lake Huron as two 'lobes of the same lake'). Aggregated, Lake Huron-Michigan, at , "is technically the world's largest freshwater lake." When counted separately, Lake Superior is larger than Huron and higher. Lake Superior drains into the St. Marys River which then flows southward into Lake Huron. The water then flows south to the St. Clair River, at Port Huron, Michigan and Sarnia, Ontario. The Great Lakes Waterway continues thence to Lake St. Clair; the Detroit River and Detroit, Michigan; into Lake Erie and thence – via Lake Ontario and the St. Lawrence River – to the Atlantic Ocean. Like the other