Five Structures That Defined L.A.’s Age of Concrete

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What was an adobe village in the mid-19th century had become, by the mid-20th, a concrete city. Modern Los Angeles, it seemed, could mold this mixture of water, cement, and aggregate – much of it locally quarried sand, gravel, and crushed stone – into an endless variety of forms with which to master nature, conquer distance, and solve nearly all its civil engineering problems.

But the progress concrete once embodied seems today as brittle as some of its aging structures. Concrete dams and canals harnessed the power and diverted the flow of distant rivers – and also bred an unsustainable addiction to imported resources. Concrete pavement connected far-flung corners of the city in the form of freeways – roadways that divide and pollute neighborhoods. Concrete channels protected residents from the Southern California’s occasional but devastating deluges – and erased some of the city’s few remaining wild landscapes.

1. Hoover Dam

It straddles the Nevada-Arizona border, hundreds of miles from Los Angeles, but this massive concrete structure – the largest in the world when it opened in 1936 as Boulder Dam – is a vital part of the metropolis’ civil infrastructure. Southern California and its Metropolitan Water District (see below) consume more than half of the electricity generated by the waters of Lake Mead rushing through its turbines.

2. Colorado River Aqueduct

Southern California’s postwar population boom would not have been possible without its 1,800 cubic-foot flow. Built between 1933 and 1939, the Metropolitan Water District’s Colorado River Aqueduct crosses 242 miles of baked and parched, faulted and folded terrain and – unlike the city of L.A.’s gravity-flow aqueduct from Owens Valley – climbs 900 net feet from its intake at Parker Dam to its terminus at Lake Matthews. (Pumps powered by Hoover Dam electricity allow the water to flow uphill.) Concrete lines the aqueduct’s 63 miles of open canals and is an essential component of its 58 miles of buried conduits and 92 miles of mountain tunnels. The project has been hailed as a marvel of modern engineering, but critics say its cheap, subsidized water stimulated demand more than anything, deepening the region’s dependence on distant watersheds.

3. Four-Level Interchange

The world’s first stack interchange, this structure of concrete curves and columns binds the 110 freeway to the 101. When completed in 1949, it represented a vast improvement over the older cloverleaf model. By stacking the eight directions of traffic into four levels, its vertical design kept traffic flowing and minimized the urban land required for the interchange. Nevertheless, its construction still forced thousands of Angelenos from their homes.

4. Dodger Stadium

An army of construction workers spent three years between 1959 and 1962 reengineering the topography of the Elysian Hills. They moved eight million cubic yards of earth to form a bowl-shaped amphitheater and flat-topped parking lots, and then reinforced their work with 40,000 cubic yards of concrete. Today the third-oldest major league ballpark, Dodger Stadium represents one of baseball’s few remaining examples of mid-century modern design – and still triggers painful memories of a neighborhood erased.

5. Los Angeles River Flood Control Channel

Built in the wake of the deluge of 1938, the concrete flood control channel tamed an unpredictable river. It also reinforced L.A.’s dependence on imported water. With each passing storm, Los Angeles River now rushes billions of gallons of local rainfall directly to the sea – water that otherwise might recharge depleted aquifers.

This article was originally published May 2, 2017.