reach the many camps along the upper San Gabriel. Although hiking popularity temporarily declined during World War II, recreation increased once more during the postwar population boom, and the upper San Gabriel continues to see heavy use today for hiking, camping, fishing, swimming and backpacking. River modifications and modern uses Flood control Prior to the early 1900s the San Gabriel River watershed was mostly used for agriculture and ranching; during the river's periodic floods, loss of life and property was limited. The river's changing course below the Whittier Narrows made it difficult to establish permanent settlements there. During most of the 1860s, the San Gabriel River flowed southwest and joined the Los Angeles River to empty into San Pedro Bay. However, a flood in 1868 caused the river to swing into a more southerly course, towards its present mouth at Alamitos Bay, flooding and destroying the town of Galatin. The old western channel is today's Rio Hondo ("deep river"). The new channel, roughly its present course, was for a time referred to as "New River". After the flood of 1938, the U.S. Army Corps of Engineers built the two large flood control basins on the lower San Gabriel River – Santa Fe Dam and Whittier Narrows Dam, completed in 1949 and 1957, respectively. Although both dams had already been proposed prior to the 1938 flood, emergency federal funding made available in the Flood Control Act of 1941 were used to expedite their construction. There is no permanent storage at either dam; their combined capacity of is used solely for flood control. A second purpose of Santa Fe Dam is to hold back destructive debris flows from the San Gabriel Canyon, as had occurred in 1938. Whittier Narrows Dam can divert excess floodwaters between the San Gabriel River and Rio Hondo as necessary. These supplement the protection provided by the upstream San Gabriel and Cogswell Dams, where the Los Angeles Department of Public Works maintains a minimum of of storage space at the beginning of each winter to protect against flooding. Another legacy of the 1938 flood was the channelization of Southern California streams, including the San Gabriel River. As a result, nearly the entire lower river has been turned into an artificial channel. However, unlike the nearby Los Angeles River which was almost entirely concreted in the wake of the 1938 flood, only about of the San Gabriel River channel