The Los Angeles River was once a vital resource to the first peoples of Los Angeles, the Tongva, and to a variety of plant and animal life. Today it runs through a 51 mile concrete channel that reduces the risk of flooding but denies Angelenos access to this beautiful and important natural resource. In recent years, groups like Friends of the LA River have joined together to demand and affect change, resulting in a Los Angeles County Master Plan for the river's revitalization.