Poopó (pō'ōpō`), salt lake, on the high plateau of W Bolivia. It is more than 11,000 ft (3,353 m) above sea level. Although it is Bolivia's second largest lake (965 sq mi/2,499 sq km) when water is plentiful, it is relatively shallow, averaging 10 ft (3 m) in depth, and can greatly decrease in size during times of drought; in the 1940s, Poopó disappeared for a time. Fed by the Desaguadero River in an area of interior drainage, it has no outlet except in time of flood, when it drains W to the Salar de Coipasa, a salt flat. In the early 21st cent., drought combined with reduced water from diminishing Andean glaciers and diversion of water upstream for mining and agriculture shrank the lake to less than 5% of its former water level by the beginning of 2016. Poopó's waters have also been polluted by mining waste.