[2][3][4][7] A 38,000 ha site encompassing the lake and its surrounds has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant populations of white-bellied chachalacas, lesser ground-cuckoos, Pacific screech-owls, orange-fronted parakeets, Nutting's flycatchers and white-throated magpie-jays.

[2][3] In 1973, President Arturo Armando Molina began the construction of the Cerrón Grande Hydroelectric Dam, and it was fully flooded by December 1976.

[5] An investigation by the Salvadoran Association of Human Aid Pro-Vida found high levels of contamination and pollution such as "[h]eavy metals, banned insecticides, cyanides, fecal bacteria, and toxic algae", which negatively affects the health of people and animals living near and around the reservoir.

[5] Large amounts of waste are dumped into the reservoir from San Salvador via the Acelhuate River[7][11][12] (as much as 4,000,000 kilograms (8,800,000 lb) of feces monthly).

[5][7] Toxic substances such as cyanide and Dieldrin, an insecticide whose importation and distribution (but not usage) was banned by the Salvadoran government in 2000, have been found in abundance in the waters of the reservoir.