In arid regions subject to intense seasonal rains, is used in geomorphology the term ephemeral lakes to indicate shallow depressions filled by meteoric contributions during the rainy season and subjected to rapid drying to the intense evaporation during the dry season. The evaporation of meteoric water causes the concentration and the progressive deposition of salts in the order carbonates, sulphates and chlorides, giving rise to salt deposits in the form of surface crusts and nodules.
Most lakes has a relatively short life on geological scale as are cleared by two phenomena burial due to sedimentation in correspondence of the tributaries, due to a sudden drop in the speed of the current; erosion threshold the lowest point of the edge of the lake basin by emissary. To these, for lakes with low edges and suitable climate, plus the landfill due to the growth of reeds and other vegetation from the shore. An example of this phenomenon is the Lake Trasimeno.