Industrial Revolution and Rapid Population Expansion until 1938
In 1850, the United States took control of California. Prior to that, descriptions of the river’s behavior, particularly its flooding patterns, existed primarily as “local lore."
When the publication of LA’s first newspaper La Estrella (The Star) began in 1851, however, it infused the historical record with detail.1Gumprecht, Blake. The Los Angeles River: Its Life, Death, and Possible Rebirth. Baltimore: Johns Hopkins University Press, 2001. 144 Written accounts from the last half of the 19th century show that LA County experienced floods that overtopped the banks of rivers and streams once every 4.5 years, with the LA River itself flooding 11 times.2Gumprecht, Blake. The Los Angeles River: Its Life, Death, and Possible Rebirth. Baltimore: Johns Hopkins University Press, 2001. 144
Historical Flash Rain and Flood Events
The damage caused by flooding progressively increased as real estate speculators such as the LA Suburban Homes Company subdivided agricultural lands near the river for urban development. Industrial development also introduced new challenges to flood risk management. Flood damages intensified, for example, when the Southern Pacific Railroad (Transcontinental) connected to the City of LA in 1876. The tracks ran adjacent to, and sometimes bridged over, the river, constricting flows. The construction of ports near the river’s outflow into the Pacific Ocean in the early decades of the 20th century established the LA River as an armature for goods movement infrastructure including additional rail lines and eventually highways.
The population and development boom catalyzed by the introduction of the railroad in LA County also hindered any efforts to stabilize the use of water from the LA River. By this point, the LA City Water Company (later to become LA Department of Water and Power) had developed strategies to tap the river during dry weather, harvesting water before it could reach the surface (except in the Glendale Narrows, where water continued to be tapped above ground). Between 1870 and 1880, the population of LA County nearly doubled. It then tripled between 1880-1890.3Gumprecht, Blake. The Los Angeles River: Its Life, Death, and Possible Rebirth. Baltimore: Johns Hopkins University Press, 2001. 163 The continued urban development within the floodplain of the river, with both farms and industry drawing water, ensured that segments of the river became so dry that they could serve as reliable sources of sand and gravel for construction crews. Devoid of visible flowing water, the LA River became the city’s dump.
Urbanization Patterns in LA County from 1877 to 2010
But water still arrived in the channel from time to time, especially when it rained. Occasional large floods significantly damaged new development within the river’s natural floodplain. In 1914, a massive flood prompted LA County to create an official flood control program, which became the LA County Flood Control District (LACFCD) in 1915. The LACFCD proceeded with a variety of engineering projects to provide permanent pathways for runoff, slow flow, and collect and filter out debris, eventually aspiring toward a regional plan to address both flood management and water conservation.4Kim, Esther. “Restoring a River to Reclaim a City?: The Politics of Urban Sustainability and Environmental Justice in the Los Angeles River Watershed.” PhD diss., University of California, Berkeley, 2017. In March 1938, however, the largest and most damaging flood experienced by modern LA to-date propelled the US Army Corps of Engineers to channelize and concretize the LA River.