The Arroyo Seco Foundation is a non-profit education and action organization. Our goal is to preserve and enhance the Arroyo Seco watershed from the San Gabriel Mountains to the Los Angeles River, to reforest our region and to promote environmental awareness. The Arroyo Seco is a major tributary of the Los Angeles River in Los Angeles County and includes the communities of northeast Los Angeles, South Pasadena, Pasadena, Altadena, La Cañada Flintridge and portions of the Angeles National Forest.