Hudson Bay drainage basin
The Hudson Bay drainage basin is the drainage basin in northern North America where surface water empties into Hudson Bay and adjoining waters. Spanning an area of about , the basin is almost totally in Canada (spanning parts of the Prairies, central and northern Canada), with a small portion in the United States (in Montana, the Dakotas, and Minnesota). The watershed's headwaters are in part on the Continental Divide of the Americas, and the watershed's connection to the Labrador Sea is at the Hudson Strait's mouth between Resolution Island in the Qikiqtaaluk Region and Cape Chidley on the Labrador Peninsula. On the Continental Divide the basin is bounded at Triple Divide Peak to the south, and Snow Dome to the north.
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.