Los Angeles Flood of 1938: Cementing the River's Future | KCET
Los Angeles Flood of 1938: Cementing the River's Future
In observance of the 1938 flood, this is the third in a four-part series explaining why and how the Los Angeles River was channelized. Don't miss part one, part two, and part four of the series. Explore the history and current issues of the river in Departures: L.A. River.
Between February 27th and March 3rd, 1938 Los Angeles was inundated with two storm systems delivering record breaking rainfalls. By March 3rd, the San Gabriel Mountains received 32 inches of rain, more than their average yearly total, and Los Angeles received over 10 inches of rainfall over the 5-day storm. 115 people lost their lives, thousands more were evacuated, over 6000 homes were damaged or destroyed, and 108,000 acres - one third of Los Angeles - was flooded. The San Fernando Valley, Venice, Compton, and Long Beach were the worst hit. The Los Angeles River was completely warped - new inlets were carved by the rushing water and the channels in areas shifted, nearly as much as a mile as was the case in Compton.
More about the channelization efforts after the photos:
Los Angeles was devastated. After previous floods in 1914 and 1934, this was the final blow, the public demanded flood control, pointing to the Los Angeles River as the culprit. Burdened with a history of flooding, the county had already instated a few flood control measures - without Devil's Gate Dam for instance, the 1938 flood would have been much worse.
Total channelization of the river began a few months later. With funding from the Works Progress Administration and the federal government as a result of the Flood Control Act, contractors and construction crews worked around the clock under the supervision of the U.S. Army Corps of Engineers, lowering and widening the channel and cementing the banks and river bottom. By the end, 20 years later, contractors had moved "twenty million cubic yards of earth (roughly 800,000 dump truck loads worth). They mixed 3.5 million barrels of cement, placed 147 million pounds of reinforced steel, and set 460,000 tons of stones.," according to Blake Grumpecht's "The Los Angeles River, Its Life, Death and Possible Rebirth." 278 miles of river and tributaries were retrofitted and more than 300 bridges were built.
With the river encased in cement, the natural sharp turns were now straightened. Any evidence of vegetation was completely removed, allowing runoff from the San Gabriel Mountains to escape through the river and out of Long Beach at up to 45 miles-per-hour. Streets and sewers were connected to drains along the river, designed to quickly capture and move rainfall away from the surrounding streets.
The river's intricate flood control system was tested in 1969 with another record breaking rain - 13 inches of rainfall over 9 days. While the engineered channel successfully prevented potential flooding in the Los Angeles Basin, mudslides in the foothills took 73 lives.
Los Angeles over the years continued to raise walls in attempts to contain nature as the population expanded to the edge of the river's boundary. Lives continued to be lost by accident or negligence, as the reality of nature is blunted by the artificial buffer of cement and rebar. As advocates push to revitalize the river to the glory days that our parents and their parents enjoyed along the river, we must be sensitive to the fierce natural powers of our river.