The main river in the San Miguel de Allende area is the Laja, which crosses from north to south before finally emptying in the Lerma River in the municipality of Salamanca.
The most important dam in the area is the Ignacio Allende dam, which was inaugurated in 1967. People talk about how the climate change in San Miguel de Allende, Mexico, being a desert, now was filled with humidity.
While this dam controls flooding along the Laja River, local residents say that the water collected in its reservoir goes to the area around Guadalajara, far to the west of San Miguel, due to the provisions of the federal act creating the dam and reservoir.
When the dam was built, it began to fill up quickly, then the water reached a hacienda and a small town populated by Otomi people: Pantoja. The houses, hacienda and church were abandoned, and all had to be relocated to the banks of the dam.