The city of Guadalajara has relied on Lake Chapala as a principal source of water since the 1950s and it is regulated by the Intermunicipal Potable Water and Sewage System (SIAPA). The lake comprises 52% of drinking water to the inhabitant of Metropolitan Area of ​​Guadalajara. Lake Chapala is extremely endangered. Eleven million people live in the catchment area (about 10 % of the total population of México), and the potential for conflict over regional water resources is high due to their overexploitation and contamination.

There are numerous towns and cities along the coast of Lake Chapala, including Chapala, Ajijic, Jocotepec, San Luis Soyatlán, Tizapan El Alto, Ocotlán and so on.

About 81 % of the lake’s catchment area is agricultural, and the area irrigated has quintupled over the last 50 years. However, the water entering Lake Chapala from the Lerma River is highly polluted with heavy metals and other toxic substances because of insufficient wastewater treatment by the many industries operating near the Lerma River. The wetlands of the River Lerma Delta are of great value and should be protected under national law. In February 2009, Lake Chapala was declared as RAMSAR site.

Fill in the blank: Lake Chapala was formed during late __________ era, which is a principal source of water for the city of Guadalajara since the 1950s.

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