Watershed

From BWCAWiki

A watershed is a region of land where water from rain or snowmelt drains downhill into a body of water, such as a river, lake, estuary, wetland, sea or ocean. The drainage basin includes both the streams and rivers that convey the water as well as the land surfaces from which water drains into those channels. The drainage basin acts like a funnel - collecting all the water within the area covered by the basin and channeling it into a waterway. Each drainage basin is separated topographically from adjacent basins by a ridge, hill or mountain, which is known as a water divide.

In addition to watershed, the following terms can be used to describe the same concept:

• catchment, catchment area, or catchment basin
• drainage basin
• drainage area
• river basin

Contents 1 Watersheds in the BWCAW 1.1 Lake Superior sub-basins 1.2 Hudson Bay sub-basins 1.3 Divides 2 References

Watersheds in the BWCAW

Due to the relatively low relief and glacial origin of the region's landscape, the Boundary Waters has a relatively complicated system of watersheds. The Laurentian Divide, separating the Great Lakes-St. Lawrence watershed and the watershed of Hudson Bay, runs NE-SW through the eastern BWCAW.

Lake Superior sub-basins

A number of rivers drain the far eastern and southeastern BWCAW, terminating in Lake Superior.

• The Arrow River watershed reaches into the northeastern BWCAW briefly, draining South Lake, Rat Lake, Rose Lake, and Duncan Lake before flowing into Canada at Arrow Lake, down the Arrow River, and into the lower Pigeon River.
• The Pigeon River watershed includes Mountain Lake and North Fowl Lake.
• Brule River watershed
• Temperance River watershed
• St. Louis River watershed

Hudson Bay sub-basins

All water in the Hudson Bay watershed within the BWCAW flows out via the Loon River and Little Vermilion Lake and from there through Voyageurs National Park, the Rainy River, Lake of the Woods, the Winnipeg River, Lake Winnipeg, and the Nelson River into Hudson Bay.

• Maligne River watershed. The Maligne flows into Lac La Croix after collecting the waters of most of the Quetico, including the Falls Chain and Silver Falls, which itself is a collection of the waters of Saganaga Lake and its tributaries including the Granite River, Seagull River, and Northern Light Lake in the Ontario Crownlands. The Granite River basin includes Gunflint Lake and North Lake, near Height of Land portage. The Seagull River drains Seagull Lake, Alpine Lake, Ogishkemuncie Lake, Gabimichigami Lake, Little Saganaga Lake, and the Frost River, among others.
• Basswood River watershed. Before flowing into Lac La Croix, the Basswood River collects waters from the Knife Lake, Fall Lake, and Kawishiwi River areas.

Divides

• The Laurentian Divide is crossed at the Height of Land portage between South Lake and North Lake.
• Canoeists frequently cross between the Maligne River and Basswood River drainages, including at Monument Portage on the U.S.-Canada border and in the Eddy-Jenny Lake area between Ogishkemuncie and Knife Lakes.

References