Rio Hondo (California)

The Rio Hondo (Spanish for "deep river") is a river in Los Angeles County, California. Its official beginning is at a reservoir called the Whittier Narrows Reservoir; and it flows southwest to the Los Angeles River. Notably, the Whittier Narrows Reservoir is also fed by the San Gabriel River, and water can be released into either river. Therefore, the watersheds of the Los Angeles River and San Gabriel River are connected by the Rio Hondo. 
Most of the Rio Hondo is lined with concrete, but there are two places the river is free-flowing. These are the "Peck Road Water Conservation Park" and the "Whittier Narrows Recreation Area". Eaton Wash is a tributary to the Rio Hondo.