Natural monument (1947), reserve (1980). Stretched out southeast, Donuzlav has the large area and is the deepest lake in the Crimea. Donuzlav in it's origin is the sea-bay, separated from the sea by the sand embankment, 200-600 m wide. The lake is salty. In the upper reaches it so narrows and grows shallow that resembles river; it's waters are fresh with spring water.