Mackenzie River
At , the Mackenzie River drainage basin encompasses nearly 20 percent of Canada. About , or 54 percent of the basin, lies above Great Slave Lake. Permafrost underlies about three-quarters of the watershed, reaching up to deep in the Mackenzie Delta. As a whole, the Mackenzie basin receives only meager to moderate rainfall, averaging over the entire basin, though mountain areas experience much higher precipitation, and areas near and north of the Arctic Circle receive much lower precipitation.
Nutrient cycling in the Columbia River Basin
Beginning in the 1930s with the construction of the Bonneville and Grand Coulee dams, the Columbia River has experienced significant modification to its flow. Today, the US Army Corps of Engineers recognize over 250 reservoirs, 150 hydroelectric projects, and 18 mainstem dams on the Columbia and its main tributary, the Snake River. Dams have been shown to directly impact nutrient cycling within the Columbia river basin through the formation of reservoirs which dramatically alter river hydrology and discharge rates and as a result constitute a major anthroprogenic impact on nutrient cycling in the river. Due to its size and the large number of dams within the basin, the Columbia River basin is often used as representative case study on how dams an impact nutrient cycling of watersheds in general. Notably, dam construction in the Columbia River Basin has impacted relative nutrient ratios, methane production, and salmon migration.