Dugout

(1) An artificially constructed depression that collects and stores water and differs from a reservoir in that a dam is not relied upon to impound water. cf. stockpond. (2) A large hole dug in the ground, frequently on the side of a hill, and often covered with logs and sod, used as a dwelling or shelter.

Source
Society for Range Management. 1998. Glossary of terms used in range management, fourth edition. Edited by the Glossary Update Task Group, Thomas E. Bedell, Chairman. Used with permission.