Lake Bassano was a proglacial lake that formed in the Late Pleistocene during the deglaciation of south-central Alberta by the impoundment of a re-established drainage system and addition of glacial meltwater. It is associated with the development of through-flowing drainage within the Red Deer River basin in particular, and the South Saskatchewan drainage network in general. Approximately 7,500 square kilometres (2,900 sq mi) of the is covered with lacustrine sediments. These sediments are bordered by the topographically higher Buffalo Lake Moraine to the west, the Suffield Moraine to the east and the Lethbridge Moraine to the south.