Michoacan is one of the states located in the center west of Mexico located on the Pacific Coast. The Sierra Madre del Sur mountain range crosses through the state and this part of the range is called the Trans-Mexican Volcanic Belt for its large number of active and non active volcanoes. There are five protected areas with 133,400 acres in the highland fir forests, where tens of millions of North American monarch butterflies migrate for their winter home.
A lot of the historical environmental degradation in the highlands is associated with colonial land use changes including the introduction of livestock and the use of the plow. These impacts were further exacerbated by the monopolization of resources and vast tracts of monoculture, rapid population expansion, and climatic drying.
In the capital, Morelia, despite the high levels of precipitation including a mean annual rainfall of 50 in, due to the high permeability of the sub soil volcanic rock there are no permanent bodies of surface water (lakes or rivers) and few springs or water holes. Instead traditional sources of water are: rainwater and small intermittent springs and waterholes that usually dry up as soon as the rainy season ends. The two largest rivers, the Balsas and Lerma are in the south of the state. Including its three major tributaries, the Laja, Apaseo, and Turbio, the Lerma constitutes the largest river system in Mexico and is of great importance to regional agriculture irrigation. The Lerma river has suffered chronic pollution problems from: untreated waste water discharge, as well as pollutant run off from meat, dairy, produce, pulp and paper, petrochemical and chemical product industries along the river.
- Encyclopedia of the Nations
- Georgina H. Endfield and Sarah L. O'Hara. Degradation, Drought, and Dissent: An Environmental History of Colonial Michoacan, West Central Mexico. Annals of the Association of American Geographers. Vol. 89, No. 3 (Sep., 1999), pp. 402-419
- Petri S. Juuti, Tapio S. Katko, Heikki S. Vuorinen. Environmental history of water: global views on community water supply and sanitation. IWA Publishing, 2007. http://books.google.com.mx/books?id=x7Ov-mVPjZ0C&printsec=frontcover&hl=en#v=onepage&q&f=false
- Helmer, Richard and Hespanhol, Ivanildo. Water Pollution Control - A Guide to the Use of Water Quality Management Principles. Case Study VIII- Lerma-Chapala Basin, Mexico. 1997 WHO/ United Nations Environment Program UNEP. http://www.who.int/water_sanitation_health/resourcesquality/wpccasestudy8.pdf