When do lake and ponds form?

Lakes and ponds usually form as depressions are excavated or dammed. Examples of erosional processes by glaciers are gouging by continental ice sheets such as during the Pleistocene glaciations in the northern parts of the United States, Europe, and Asia when continental ice sheets eroded deep basins that then acted as collecting basins when the glaciers eventually disintegrated and melted; lakes like Seneca Lake in New York were formed in this manner.