List of unusual drainage systems

The following is a list of unusual drainage systems.

List

The Casiquiare canal - natural waterway connecting the Orinoco and Amazon rivers.
The Chicago River artificially diverts water from the Great Lakes to the Mississippi.
The Echimamish River in Canada connects the Hayes and Nelson rivers and was much used as a shortcut by voyageurs.
The Nerodimka flows into the Aegean and Black seas.
Parting of the Waters, Wyoming
Arroyo Partido, Neuquén, Argentina
Slims River: In the spring of 2016 a melting glacier diverted most of the Slims River from the Bering Sea to the Gulf of Alaska watershed.
Tärendö River - in Sweden

The Chu River in Kyrgyzstan flows east to within a few miles of Lake Issyk-Kul, makes a hairpin turn, and flows west without entering the lake.
The Manych River east of the Black Sea formerly flowed both east and west.

Bontecou Lake in New York outflows into two watersheds, those of the Hudson and Housatonic rivers.
The artificial Gatun Lake in Panama drains into the Atlantic and Pacific.
Isa Lake in Yellowstone National Park drains to the Atlantic and Pacific.
At the summit of Simpson Pass in the Canadian Rockies is a small lake, the Committee's Punch Bowl, that drains both east and west.
Wollaston Lake is a bifurcation lake that drains northwest to the Arctic Ocean and northeast to Hudson Bay.
Lake Diefenbaker - in Canada
Inhottu - in Finland
Isojärvi (Satakunta) - in Finland
Kivesjärvi - in Finland
Kuolimo - in Finland
Lummene - in Finland
Vehkajärvi - in Finland
Vesijako - in Finland
Lake Manapouri in New Zealand has been modified as part of a hydroelectric scheme such that it drains (naturally) south to Foveaux Strait via the Waiau River and (artificially) west via a constructed tunnel to Doubtful Sound