Tres Marias Wastewater Treatment Plant, Morelia, Michoacán, Mexico

Tres Marias is a wastewater treatment plant located in Morelia, Michoacán, Mexico, serving a population of about 22,818. The facility is situated inland, more than 50 km from the coast, and plays a role in managing municipal wastewater for the region. In Mexico, wastewater treatment plants of this scale are typically regulated under the National Water Law (Ley de Aguas Nacionales) and must comply with official standards (NOM-001-SEMARNAT-1996) for discharge quality, which set limits on pollutants based on receiving water body type. The treated effluent likely discharges into a local watercourse that eventually drains into the Lerma River basin or the Lake Cuitzeo basin, both ecologically significant areas. The Lerma River is a major water source for central Mexico, supporting agriculture and biodiversity, while Lake Cuitzeo is a large endorheic lake important for migratory birds.

The plant's discharge likely enters a tributary of the Lerma River or flows into Lake Cuitzeo, a large shallow lake that is a critical habitat for waterfowl and migratory birds. The Lerma River basin is heavily utilized for agriculture and urban water supply, making proper treatment essential to prevent eutrophication and protect downstream ecosystems. The region's volcanic terrain influences local hydrology, with seasonal rainfall affecting flow rates.