This region of Jalisco is characterized by four major rivers that have their sources high in the mountains before crossing through farmlands and forests in the municipalities of CostAlegre, until they eventually reach the coast. They are the main source of water for all communities, farming, ranching, and coastal tourism developments. Unfortunately, they are also the catchment basins for land and water pollution caused by poorly managed and malfunctioning water treatment facilities, or direct runoff. Land pollution such as trash, chemicals, and soil erosion further burden the rivers, and, as a consequence, the estuaries and near-shore reefs.