which has not been built due to environmental concerns and falling oil and gas prices. Transportation During the ice-free season, the Mackenzie is a major transportation link through the vast wilderness of northern Canada, linking the many isolated communities along its course. Wide, calm sections of the river are frequently used to land seaplanes in the ice-free season. Canada's northernmost major railhead is located at the town of Hay River, on the south shore of Great Slave Lake. Goods shipped there by train and truck are loaded onto barges of the Inuit-owned Northern Transportation Company. In 2016, Northern Transportation Company went bankrupt, and its assets were bought by the government of Northwest Territories. Barge traffic travels the entire length of the Mackenzie in long "trains" of up to fifteen shallow-draft vessels pulled by tugboats. Goods are shipped as far as the port of Tuktoyaktuk on the eastern end of the Mackenzie Delta, where they are transferred to oceangoing vessels and delivered to communities along Canada's Arctic coast and the numerous islands to the north. In winter, the frozen channel of the Mackenzie River, especially in the delta region, is used as an ice road, firm enough to support large trucks, although travel between northern communities is mostly by dog sleds and snowmobiles. Although the Mackenzie River is wide and deep, navigation is "notoriously difficult" due to the locations of sandbars and shallows changing from year to year. In some narrower parts of the river, barges must be uncoupled and towed one by one through hazardous stretches, despite attempts to widen and deepening the channel by blasting. Hydroelectricity Although there are no dams along the main stem of the Mackenzie, many of its tributaries and headwaters have been developed for hydroelectricity production, flood control and irrigation. The W.A.C. Bennett and Peace Canyon hydroelectric dams on the upper Peace River were completed in 1968 and 1980 by BC Hydro. They have a combined capacity of more than 3,600 megawatts (MW). The reservoir of W.A.C. Bennett, Williston Lake, is the largest body of fresh water in BC and the ninth largest man-made lake in the world, with a volume of . Other smaller hydroelectric plants are located along the Snare and Taltson River tributaries, providing power to mines in the Great Slave Lake region. By acting as a massive stabilizer on the water flow of the Peace River, Williston Lake reduces flood crests