The Arroyo Seco, which has been called Southern California's most celebrated canyon, links the San Gabriel Mountains to the Los Angeles River near downtown Los Angeles.  It includes a dramatic mountain watershed and an urbanized canyon and plane which hosts the Rose Bowl, Jet Propulsion Laboratory, the Southwest Museum, and a variety of environmental and cultural treasures. 

Two non-govermental organizations, the Arroyo Seco Foundation and North East Trees, initiated this project with a vision to restore and better manage the Arroyo Seco watershed. The first step was the development of the Arroyo Seco Watershed Restoration Feasibility Study issued in May, 2002.  This program assessed resource challenges, including flood and stream management, habitat restoration, water resources and recreational opportunities in the watershed and identified goals and projects for conservation, better management, and restoration.  Two organizational vehicles were established to link and coordinate the efforts of agencies, organizations and individuals working to promote better watershed maangement.  The first, the Council of Arroyo Seco Agencies (CASA), brings together the major governmental entities that have management, planning or regulatory responsibility in the Arroyo Seco.  The second, the Council of Arroyo Seco Organizations (CASO), provides a forum for neighborhood and community based organizations as well as environmental groups to discuss issues and programs in the watershed and to collaborate. 

The Arroyo Seco Watershed Coordination Program, funded by the California Department of Conservation, provides organizational support to these efforts and has undertaken wide-ranging educational programs in water resources, conservation and the environment. Groups are now working together to develop the Arroyo Seco Greenway, which will unite efforts throughout the watershed to link up trails, restore habitat, and promote a greater awareness of the history, culture, and natural resources of the Arroyo Seco.  A cooperative agreement between the governmental entities is now being developed to provide a framework for programs and a commitment to goals.