Lake Amatitlan is the fourth largest lake in Guatemala, located 16 km the south of the capital Guatemala City at an altitude of 1,188 m. The lake was traditionally used as a water source and for transportation, recreation and fisheries. Each year large quantities of untreated sewage, industrial waste and sediment are carried into the lake contributing to high levels of pollution of the lake's water and has seriously affected the lake's former function as a source of drinking water and irrigation, and reduced its recreational functions.