Bifurcation lake

Lake Vesijako in Padasjoki, Finland

A bifurcation lake is a lake that naturally has outflows into two different drainage basins and thus the drainage divide cannot be defined exactly because it is situated in the middle of the lake.

Examples

Two nearby lakes in Finland are Vesijako (the name Vesijako actually means "drainage divide") and Lummene in the Finnish Lakeland both drain in two directions: into the Kymijoki basin that drains into the Gulf of Finland and into the Kokemäenjoki basin that drains into the Gulf of Bothnia.

Similarly the lakes Isojärvi and Inhottu in the Karvianjoki basin in the Satakunta region in western Finland both have two outlets: from Inhottu the waters flow into the Gulf of Bothnia through Eteläjoki in Pori and into lake Isojärvi through Pomarkunjoki River. From lake Isojärvi the waters flow to Gulf of bothnia trough Pohjajoki river in Pori and trough Merikarvianjoki river in Merikarvia. In Karvianjoki basin there has formerly been also two other bifurcations which however no longer exist due to human action.

Lake Diefenbaker in Saskatchewan is a reservoir created by damming South Saskatchewan River and Qu'Appelle River. The lake continues to drain into the two rivers, however the Qu'Appelle receives a much enlarged flow (in essence, a diversion of flow from the South Saskatchewan) due to the damming. Both rivers eventually drain into Hudson Bay via Lake Winnipeg and the Nelson River.

Isa Lake in Yellowstone National Park is believed to be the only natural bifurcated lake in the world to drain backwards into two oceans. Its western drainage is to the Atlantic Ocean via the Firehole River, while its eastern drainage is to the Pacific Ocean via the Lewis River.

Also located in Saskatchewan is Wollaston Lake, which is the source of Fond du Lac River draining into the Arctic Ocean and of Cochrane River draining into Hudson Bay. If Hudson Bay is considered part of the Atlantic Ocean (and, if the Arctic Ocean is not also considered part of the Atlantic), then Wollaston Lake is the largest bifurcation lake that flows naturally into two oceans.

The Casiquiare river, also known as the Casiquiare canal is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the largest river on the planet that links two major river systems.

See also

References

External links

Media related to Bifurcation lakes at Wikimedia Commons