Rio Hondo

The Rio Hondo is a tributary of the Los Angeles River in Los Angeles County, California, approximately 16.4 miles long. As a named river, it begins in Irwindale and flows southwest to its confluence in South Gate, passing through several cities . Above Irwindale its main stem is known as Santa Anita Creek, which extends another 10 miles northwards into the San Gabriel Mountains where the source, or headwaters, of the river are found.

The Rio Hondo has sometimes been described as a second channel of the San Gabriel River. For much of its length, the rivers flow parallel to each other about two miles apart. Both rivers pass through the Whittier Narrows, a natural gap in the hills which form the southern boundary of the San Gabriel Valley. Here, both rivers are impounded by the Whittier Narrows Dam, which the Army Corps of Engineers describes as, "the central element of the Los Angeles County Drainage Area flood control system". During major storms, the outlet works at Whittier Narrows Dam can direct water to either channel, or runoff can be stored.

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