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1938 Until the Present

The concretization of the river was the pinnacle of a transformative flood management project that continued well into the second half of the 20th century and has functioned successfully for decades.

It marks the USACE conversion of the river into single-benefit infrastructure designed for one job: to quickly funnel storm flows to the ocean and spare surrounding areas from flooding. In the context of New Deal America, the presence of structured channels and dams represented the ability of human engineering to defend communities against the river’s “vagrant waters.”1 Kim, 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.

Yet, at the same time, they shifted both the function and public perception of the river. New homes and businesses built their backs to the channel. By the middle of the 20th century, the majority of the low-lying areas of the LA River watershed were urbanized. The river was spoken of almost exclusively in terms of its flood management functions, and its role in the greater ecosystem began to wane. The vast majority of plants and fauna that had existed for millennia along the LA River suffered.

Many communities have faced hardship due to the extensive modifications that people have made to the river and natural watershed. For Indigenous Peoples, this comes in the form of multiple generations of displacement and cultural erasure. For others who underpinned the burgeoning citrus industry in the early 20th century and the Mexican, Chinese, and Japanese truck farmers who initially settled in the Elysian Valley,2 Kim, 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. the urbanized river divided and segregated communities, facilitating “barrioization” through formal and informal zoning.

This aerial view of the 1938 flood from above Victory Blvd, shows breaches in paved levees in and below a sharp curve in channel alignment.
USACE, 1938.
A construction crew installs the vertical walls of a box channel, c. 1948-1951.
LA Public Library.

By the 1930s, redlining maps published by the Home Owners’ Loan Corporation subjected river-adjacent neighborhoods to overt discrimination along racial and ethnic lines; areas off the river’s east bank near Downtown LA, for example, were described as “hopelessly heterogenous” and “honeycombed with diverse and subversive racial elements.”3 Robert K. Nelson, LaDale Winling, Richard Marciano, Nathan Connolly, et al. “Mapping Inequality.” American Panorama, ed. Robert K. Nelson and Edward L. Ayers. This classification established major barriers for residents seeking home loans and stalled their upward economic mobility.4 Reft, Ryan. “Segregation in the City of Angels: A 1939 Map of Housing Inequality in L.A.” KCET, 19 January 2017. Neighborhoods bypassed by this grading exercise tended to have more affluent and homogenous populations and were, by contrast, set up as white suburbs.5 Sides, Josh. L.A. City Limits: African American Los Angeles from the Great Depression to the Present. Berkeley, Los Angeles, and London: University of California Press, 2003. Redlining produced landscapes of segregation that both created and reinforced ethnic and racial “enclaves” along the river including Chinatown, Bronzeville (formerly Little Tokyo), and Sonoratown.6 Kim, 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. The legacy endures: particularly in the San Fernando Valley and south of Downtown LA, some Hispanic and Latino and Asian communities today are disproportionately challenged by deteriorating social, economic, and environmental conditions.7Gottlieb, Robert. Reinventing Los Angeles: Nature and Community in the Global City. Cambridge: MIT Press, 2007. 209.

In more recent decades, the marginalization of certain neighborhoods within the LA River corridor has taken the form of forced displacement. The freeway system, while providing much needed regional mobility, displaced close to a quarter-million people in LA County while being constructed during the 1950s and 1960s, the period of Urban Renewal.8 Masters, Nathan. “They Moved Mountains (and People) to Build LA’s Freeways.” Gizmodo, 17 March 2014. The 710 Freeway, which runs adjacent to the lower LA River, has also posed issues of environmental injustice; it has contributed to poor air quality and heightened disease rates of residents in adjacent neighborhoods. Due to rising housing costs and a limited housing supply, the displacement of populations continues to be at the forefront of issues facing river communities.

Channelization of the river was completed in the 1960s, and two particularly severe rainfalls in the coming years put the system to the test. In 1969, over a week of heavy rain caused $4.5 million in damages.9LA County Public Works. Appendix A: History of the Los Angeles River. c. 1996. Despite the destruction, however, the flood management measures were considered successful. The amount of rainfall that had reached LA–thirteen and a half inches in nine days–was record-breaking, more intense than what had befallen the less developed city in 1938. The river infrastructure was estimated to have prevented over a billion dollars in damages.10Orsi, Jared. Hazardous Metropolis: Flooding and Urban Ecology in Los Angeles. Berkeley: University of California Press, 2004. 168. Another major weather event in 1980 again reinforced the river’s ability to contend with severe rainfall and runoff, yet $375 million in damages indicated that the system could still be improved.11LA County Public Works. Appendix A: History of the Los Angeles River. c. 1996. Water rose to five feet below the top of the gates at Sepulveda Dam,12 Sheer, Julie. “Controlling Water Flow.” Los Angeles Times (January 5, 1997). splashed against 20-foot-tall levees,13 Holguin, Rick. “Rains Snarl Traffic; No Major Damage is Reported.” Los Angeles Times (February 13, 1992). and filled approximately 86% of the channel’s capacity.14 Brooks, Norman. Storms, Floods, and Debris Flows in Southern California and Arizona 1978 and 1980: Proceedings of a Symposium, September 17-18, 1980. Washington: National Academy Press, 1982. 145.

A Union Pacific locomotive is pulls a train of containers southbound, just north of Union Station in LA.
Downtowngal, Union Pacific container train Los Angeles, 2012. Source License: CC BY-SA 3.0.

Starting in the 1980s and carrying into the 1990s, visions of restoring and improving the LA River back to a more naturalized form slowly began to enter the mainstream with the emergence of influential organizations like Friends of the Los Angeles River (FoLAR), which was formed in 1986. At this same time, in the early 1990s, the US Army Corps of Engineers began its LA County Drainage Area (LACDA) project to make sweeping structural improvements to the flood channel capacity of the LA River. The LACDA project improved flood risk reduction significantly along the lower LA River. Plans such as the City of LA’s LA River Revitalization Master Plan (2007) and the Lower LA River Revitalization Plan (2017) have since continued to retune both cultural perceptions of and practical roles for the LA River.

The low-flow channel carries water down the center of an otherwise dry trapezoidal section of the LA River.
OLIN, 2018.

With nearly one million people living near the river, the need to balance water, people, and environmental goals along the LA River while maintaining its flood risk reduction purpose is greater than ever.15 Population based on census tracts that intersect a 1-mile buffer around the LA River. Calculated from U.S. Census Bureau, American Community Survey 2015–2019 5-Year Estimates, Table B01001, 2021; U.S. Census Bureau, 2016 TIGER/Line Geodatabase (machine-readable data files), 2016. With the implementation of this Master Plan, the LA River can enter the sixth key period of its history as a multi-benefit waterway: the reimagined river.

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