Toppled house on the Arroyo Seco, 1914
Photograph from Los Angeles Public Library / Security Pacific Collection, published in Blake Gumprecht, The Los Angeles River
PAST, PRESENT, AND POSSIBILITIES
1910s
By 1904 William Mulholland and other area leaders recognized that Los Angeles' population would soon exceeded the capacity of the Los Angeles River to supply the city's domestic water needs. Although the river continued to be drained, upon completion of the Owens Valley Aqueduct in 1913, the primary source of water in Los Angeles was the mountain slopes of the Eastern Sierra, over 200 miles north of city hall. Yet because aqueduct water was used to irrigate orchards in the San Fernando Valley before reaching the city, the agricultural runoff supplemented the underground reservoirs that created the Los Angeles River's dry season flow. In effect, the aqueduct extended both the length of the river and the area of its watershed.
But while urbanization was altering the region's hydrology, the river's course had yet to be fixed by flood control efforts and it was still capable overflowing its banks. Four months following the opening of the aqueduct, the Los Angeles River unleashed yet another destructive flood.