It is a basin located in the Southeast of the country with a high index of flora and fauna, its territorial extension is 91,245 km2. This basin is the most important in the Mexican Republic. It feeds the Grijalva River and the Usumacinta River. Endowed by the largest freshwater reserves in the country. It also contains one of the forest masses that harbor a high biological diversity known in Mesoamerica. Its ecosystems host 64% of biodiversity nationwide and it is also one of the main freshwater reserves in the country. The movement of these waters is considered a critical factor that organizes and connects the different fluvial and marine ecosystems of the Southeastern part of the country.