For instance, the Great Lakes' water flows into the St. Lawrence River and eventually the Atlantic Ocean.
Open lakes typically have relatively stable water levels that do not fluctuate, as input is always matched by outflow to rivers downstream.
The drainage from an open lake, like that from ordinary rivers, is referred to as exorheic (from the Greek exos, outside and rhein, to flow).
This is what has caused the shrinkage of the Aral Sea, formerly the world's second largest closed lake.
Apart from Australia and Southern Africa, it is rare for runoff variability to be high enough for these changes to take place on a useful time scale,[2] and lakes forming in areas where conversions from closed to open or open to closed are likely are very rare.
[3] Since 1999, possibly due to global warming, Devils Lake has overflowed into another terminus called Stump Lake, which could overflow into the Red River of the North if present wet conditions in the region continue.