A tinaja is a surface pocket (depression) formed in bedrock that occurs below waterfalls, that is carved out by spring flow or seepage, or that is caused by sand and gravel scouring in intermittent streams (arroyos). Tinajas are an important source of surface water storage in arid environments.
These relatively rare landforms are important ecologically, because they support unique plant communities and provide important services to terrestrial wildlife.
The term originates in Spain, being Spanish for "clay jar", and is used in the American Southwest.
Examples
The Tinajas Altas ("high tinajas") in southern Arizona. Several in El Pinacate y Gran Desierto de Altar Biosphere Reserve, Sonora, Mexico. Las Tinajas de Los Indios, California Las Tinajas, Zinapécuaro, Mexico