Sepulveda Dam, along with Hansen Dam located in the north San Fernando Valley, was constructed in response to the historic 1938 floods which killed 144 people. Sepulveda Dam was placed at what was at the time, the current edge of the city. East of the dam the river was crowded into a narrow bottom by the city's growth. One legacy of Sepulveda Dam is its flood control basin, a large and undeveloped area in the center of the Valley, used mostly for wildlife refuge and recreation. But another legacy of the 1938 Los Angeles River flood was the post-World War II channelization of all the Valley's dry washes, which along with the post-World War II rapid suburbanization left the Valley with hot, dry, concrete-lined river bottoms instead of greenbelts. Although now, in part, these are being devolved as interconnecting bike paths.