All lakes and ponds have a life cycle that begins when they are formed and ends when they are filled in with plant life.

Formation

Both lakes and ponds usually form when water collects in undrained depressions, or basins, in the ground, and any outlet, such as a stream, does not drain them completely. The source of the water may be precipitation (rain, sleet, and snow), a river, a stream, a spring, or a melting glacier. In any case, there must be enough water to keep the depression filled. In very dry regions, ponds or lakes may form during a rainy season and then disappear again when the dry season returns.

Depressions that become ponds and lakes may be created by any natural forces, animals, people, and even the wind. However, most are made by glacial, volcanic, tectonic, or riverine...