US Army Corps of Engineers completes LA River channel

This forms a 51-mile engineered waterway made of concrete. The Los Angeles County Flood Control District hires 14 contractors in 31 separate contracts and moves more than 20,000,000 cubic yards of earth, pours more than 2,000,000 cubic yards of concrete, places nearly 150,000,000 pounds of reinforced steel, and sets 460,000 tons of grouted stone slope protection.

The channelization of the LA River takes 20 years to complete, in this time the population of LA County rises to more than six million residents.