Editor’s note: In anticipation of what we all believe will be a stellar UHA conference this October 9-12 in Los Angeles, we are featuring Los Angeles as our theme this month. This is our fifth post; you can see others from this month as they are published as well as past pieces on the city here. In addition, check here for information on the conference, including accommodations.
By Charlotte Leib
Los Angeles is a city of roads. It wasn’t always that way. In the 1920’s, when Los Angeles residents first brought their Model T’s and Buicks to the spot where the now burnt-out skeleton of the Pacific Palisades Village shopping center sits, only a few roads cut through the area. Among them was the Via de la Paz. When the roadway was first constructed in the early 1920’s atop a bluff towering over the Los Angeles neighborhoods of Brentwood and Beverly Hills in the center of LA County, it reached out across the landscape like a symbol of endless possibility. During the 1930’s, the modest homes and garden bungalows of the Pacific Palisades sprouted around the road. By the 1960’s, more extravagant residences began to appear. The neighborhood quickly transformed into a preferred retreat for some of LA’s most affluent homeowners.[1]
In January 2025, during the Pacific Palisades Wildfire, the majority of the neighborhood that had developed from the 1920’s onward around the Via de la Paz went up in flames.
Simultaneously, in a horrific turn of events, the Eaton Fire burned over 3,000 acres of suburban Altadena, located 25 miles east of the Pacific Palisades and northeast of Pasadena. Developed beginning in 1887 as a wealthy, suburban farming community at the base of the San Gabriel Mountains, Altadena became a haven for Black Angelenos in the wake of the 1968 Fair Housing Act, which prohibited housing discrimination on the basis of race, religion, sex, or national origin. It remained so in decades that followed—until it burned.[2]
Over the course of Los Angeles’ history, people have perennially sought to build back better after disasters, be they fires, mudslides, earthquakes, or floods. In the months since the wildfires that destroyed much of LA’s Pacific Palisades neighborhood and, simultaneously, much of LA’s Altadena neighborhood, that trend has persisted. Property owners and city authorities alike have called for better planning, wider roads, enhanced water supplies for fighting future fires, and earlier evacuation warnings, while ignoring the dire environmental and financial costs that will likely emerge in the future when the two neighborhoods burn again.[3]
If the most popular contemporary approaches to environmental planning in Los Angeles and at the planetary scale have one common trait, it’s the fallacious supposition that new technologies and better design will prevent the next fire, the next flood, or the next degree of global heating. As John McPhee clarified in his 1988 New Yorker series “The Control of Nature: Los Angeles Against the Mountains,” and as Mike Davis has shown in his work, LA’s urban history is a case in point for how technological fixes adopted in response to the city’s recurrent landslides, fires, and floods have never really worked. As Davis has highlighted—and in a lesson that should resonate far beyond California and into contemporary environmental planning and climate change policy circles—techno-fixes like flood control, hillside stabilization, and the practice of building back better after fires have merely deepened Los Angeles’ economic and racial inequalities over the course of the city’s history.[4]
It would be an oversight not to recognize how a similar techno-optimism shapes many private and public entities’ current stance toward the climate crisis. For the Earth’s techno-optimists, be they individuals, businesses, or governments, carbon-capture and geoengineering technologies are held up as salvos for the crisis at hand—the very same crisis that made the LA fires of this past January 2025 so severe.[5]
Still, the commentators who pointed to the Pacific Palisades’ roadways as one cause for the severity of the Palisades Fire in particular were not entirely wrong. LA’s roadway infrastructure did contribute to the severity of the destructive wildfire—just not in the way critics imagined.
Before Los Angeles’ landscape evolved into an intricate tapestry of roads, grids, and freeways, significant portions of the city hosted extensive wetlands.[6] Yes, Los Angeles had wetlands. And by and large, roadways ruined them.
As this photo essay will reveal, LA’s roads have historically been more than just conduits for the consumption of gasoline, grounds for traffic jams, technologies of racial division, and vectors for the city’s transformation into a sprawling megalopolis.[7] The city’s roads have also been destroyers of wetlands and agents of myriad local environmental transformations that must be accounted for when we discuss the causes of contemporary global climate change.
Los Angeles’ roads have contributed to climate change not only for the obvious ways in which they’ve encouraged the extraction and consumption of petroleum-derived fuels. They’ve also contributed to climate change in the way they’ve required the drying-out of millions of cubic-feet of soil—soil that, were it still wet, would do much to moderate the severe wildfire events that will continue to reshape the city’s urban landscape and livability in this century.
To be sure, Los Angeles was a fire-prone city long before roadways and urban development overtook the city’s wetlands. As Ryan Reft noted in a 2013 KCET article, sizeable areas throughout Los Angeles County experienced fires in 1930, 1935, 1943, 1956, 1961, 1966-67, 1970, 1978, 1982, 1985, 1993, 1996, and 2007.[8]
Centuries before these fires, wildfire events were integral parts of Los Angeles’ ecology, to the extent that Indigenous Tongva people built their dwellings with moveable natural materials like thatch and fire-resistant mud, and adapted to the seasonal rhythms of the landscapes’ fire-prone woodlands, grasslands, and chaparral.[9]
Yet beginning in the 1920’s and 1930’s, the construction of ambitious engineering projects across LA County, mainly designed to ease automobile transport by road, began to radically alter the city’s environment and climate. The construction of compressed, oiled dirt roadbeds and the subsequent installation of impervious, heat-absorbing asphalt surfaces incited the first transformative shifts. Then came more ambitious projects, after floods and landslides threatened the passability and integrity of the city’s newly-built roads.
In 1932, after a landslide collapsed a portion of one of the Pacific Palisades’ bluffs, endangering homes on the edge of the Palisades and making the Pacific Coast Highway (then called Roosevelt Highway) impassable, Los Angeles engineer Robert A. Hill devised an energy-intensive plan to stabilize the bluff’s slide-prone clay seam. It was one of the first of many twentieth-century schemes to control of Los Angeles’ turbulent terrain, attempts that culminated in failure.
Hill’s landslide control system consisted of a circuit of tunnels dug through the cliff connected to a gas-powered furnace. For about fifteen years after the system’s installation, the furnace and a constant supply of natural gas filled tunnels embedded in the Palisades bluff with a continuous stream of hot air. The hot air forced through the tunnels was meant to dry out the bluff’s clay seam.
Hill observed that the system worked well enough at the beginning. But in a matter of years, the bluff experienced additional landslides. All throughout the twentieth century, portions of the bluff still periodically broke off, leaving the highway beneath strewn with debris.[10]
Engineers continued to manipulate Los Angeles’ soil and hydrology throughout the twentieth century with ambitious, if ineffective, land stabilization schemes like Hull’s. Flood control projects further limited the amount of water returning to Los Angeles’ terrestrial vegetation and subsoils. As with the attempted stabilization of the landslide-prone Palisades bluff, these engineering schemes were developed in direct response to perceived environmental threats—and in many cases, acute disasters.
The Los Angeles River’s currently channelized banks are perhaps the most iconic evidence of this truism. In 1938, just years after LA’s massive 1930 Decker Canyon fire burned a total of 15,000-some acres of dry brush woodland, northwest of Malibu, Los Angeles also suffered a severe, property-damaging and life-taking flood.[11]
The story of what happened next is well-known. Using federal flood control funding, the US Army Corps of Engineers (USACE) confined the Los Angeles River’s natural flow into a concrete coffin.[12]
From the 1920’s through the 1940’s, USACE also worked to channelize Ballona Creek. For thousands of years before the Spanish settlers and westward-moving American settlers claimed the Los Angeles landscape as their own, dispossessing Tongva peoples in the process, Ballona Creek had flowed freely across a wide swath of LA’s middle coastal plain. Water flows from the creek and tidal flows from the nearby Pacific Ocean had covered portions of Venice Beach and Culver City daily. Today’s Marina del Rey and Playa del Rey districts were also often covered in fresh and saltwater flows. That all changed after the construction of the first land reclamation projects along the Creek in the 1800’s, and more dramatically in the 1940’s after USACE channelized the Creek and transformed the surrounding intertidal wetlands and vernal pools into a docking marina and developable land.[13]
Ballona Creek’s channelization prepared the way for more highways, more roads, more houses—and for developers and city tax rolls, more profits. As the wetland was purposefully dried up and channelized, Los Angeles’ unrelenting demand for water simultaneously transformed the semi-arid Owens Valley and the nearby Mono Basin into manufactured deserts.[14]
We often think of LA’s freeways as merely conduits of traffic or conveyor belts for nightmare traffic jams. But they, too, contributed to the destruction and desiccation of the city’s wetlands. The city’s first freeway, the Arroyo Seco Parkway, set the process in motion. Constructed from 1938 to 1953, the freeway was euphemistically named after the seasonal creek it replaced.[15]
The Arroyo Seco Parkway did more than just bury and ruin a creek that had once freely replenished LA’s lowlands with moisture, however. Like the garden bungalows that were simultaneously budding across Los Angeles in the 1940’s and 1950’s, the landscaped parkway required water. Although city officials named the parkway after a dry creek, they intended it to be surrounded by green growth—growth that required irrigation and the further desertification of the beleaguered Owens Valley and Mono Basin.[16]
During the middle decades of the twentieth century, Los Angeles’ urban expansion onto its wetlands not only reduced the amount of moisture flowing back into the city’s atmosphere. The very presence of new, heavy structures atop former wetlands caused parts of the city’s already tectonically-active landscape to subside.
The problem was particularly severe at the Port of Los Angeles-Long Beach. In a concentric pattern, from 1928 to 1965, portions of the area around the U.S. Naval Base and the port’s piers and storage yards subsided from depths of two to as much as 28 feet.
To fix the subsiding port, California engineers employed a technology first tested by the California State Highway Commission in the construction of the San Francisco–Oakland Bay Bridge over marshland from 1933 to 1936. Concurrently, in the 1940’s through 1960’s, the technology began to be used to prepare waterlogged and otherwise unstable or un-developable lands for highways, airports, and logistics hubs around the world.[17]
The technology, that of the sand drain, served as yet another means through which to desiccate LA’s wetlands. All throughout the twentieth century, at LA’s port and beyond, geotechnical engineers issued plans that popularized the technology’s use.[18]
At every drainage site, then as now, the process of sand drainage required just a few simple but energy-intensive steps. Using giant mandrel equipment—spillover technology from the oil and gas industry—construction workers install gridded fields of sand-filled columns through formerly marshy, clay-laced plains. The workers then lay a blanket of sand over the sand columns. By dint of hydrostatic pressure within the ground plane and sand’s high permeability, water then flows upward through the sand columns and away from the construction site over the sand blanket.
Sand drain technology’s objective is to free water from the land, and make it go away. Since the 1930’s when the technology was first developed by engineers at the California Division of Highways’ Materials and Research Department, it has served as one of the most powerful ways to make a wetland disappear.
Quietly yet significantly, the global use of sand drain technology has also contributed to climate change—the very circumstance that has made LA’s recent fires so unprecedented and deadly.
Although it was not widely known when sand drains were first invented and used, cutting up wetlands with sand drains—essentially transforming them into metaphorical blocks of Swiss cheese—hastens the release of potent greenhouse gases into the atmosphere. Methane, nitrous oxide, and carbon dioxide—all drivers of atmospheric warming—are often released in the process of installing sand drains and compressing the surrounding soils.[19]
Climate scientists have recently foregrounded how the historic combustion of coal, oil, and natural gas exacerbated LA’s recent fires.[20] But on a local scale, it’s important to also account for the technologies that have reconfigured Los Angeles’ surface when we consider the factors that made the fires so severe.
Concretized channels, gargantuan freeways and sand drains enabled the purposeful desiccation of the city’s formerly seasonally-wet marshes, flood plains, and creeks. The transformations wrought by these technologies not only ruined rich, biodiverse habitats. They also made Los Angeles more susceptible to drought and more vulnerable to fires. The use of sand drains in highway and port construction applications globally in the latter half of the twentieth century also destroyed innumerable wetlands.
Both Los Angeles’ history and that of the world’s in the twentieth century would be incomplete without reference to the Great Acceleration. It’s a term that’s been used since the early 2000’s by environmental historians and earth systems scientists to frame the period during and after World War II when the world’s industrial production intensified. Greenhouse gas emissions spiked during this period, and have ever since arced upward, making it a pivotal point in the history of global climatic and environmental change.[21]
The gas-powered blowers, channelized rivers, and sand-drained ports and freeways detailed in this essay all contributed to the Great Acceleration. They sped up nature’s time—the pace of life that had for entire geological epochs governed Los Angeles’ geological and terrestrial transformation—and sapped crucial moisture from LA’s above-ground and subterranean environments in the process.
To truly know the factors that combined to cause the Great Acceleration and the climatic conditions that exacerbated the intensity of LA’s recent fires requires attending to the landscapes that Los Angeles lost in the twentieth century. Chief among those losses were the city’s wetlands.
For thousands of years, humans have perennially wrung life out of wetlands. They have reclaimed, rechanneled, and repurposed them, making them serve urban, agricultural, and more recently, industrial ends. Before LA and parts of its Ballona Creek Wetland became major oil-drilling sites in the late-nineteenth and early-twentieth centuries, settlers transformed the city’s wetlands and grasslands into haying fields to feed and fuel their oxen, mules, and horses. These were the animals that graded LA’s first roads and that surveyors used to lay out the streets of the recently charred and devastated Pacific Palisades.
Once cars came along, well, the rest is history. Los Angeles was concretized. It became a city of roads. Its creeks, once pulsing with water and life, were channelized. Its wetlands were drained.
When we take stock of the myriad causes of the 2025 Pacific Palisades and Eaton Fires and consider the causes of contemporary climate change, it can’t just be carbon emissions we track, or global temperature rise. We have to account for transformations in local landscapes. That’s the power of urban landscape history. It’s a field of inquiry that reveals not just how cities and landscapes transform, but why cities like Los Angeles burn—and why it might just be another misguided techno-fix to try to change that.
Charlotte Leib is a Ph.D. Candidate in History at Yale University. She holds dual Masters degrees in Landscape Architecture and in the History and Philosophy of Design and Media from Harvard University, and a Bachelor of Arts in Architecture, with certificates in Urban Studies and American Studies from Princeton University. At Princeton, she wrote her undergraduate thesis on the history of community gardening in Los Angeles during the nineteenth and twentieth centuries. Her prior knowledge of Los Angeles’ urban landscape history, and her research for her dissertation, an environmental and energy history of the New Jersey Meadowlands, led her to examine the sand drain technologies discussed in this essay.
Featured image (at top): “Easter Sunrise Services on Peace Hill in Pacific Palisades,” 1922, photographic print. Santa Monica Public Library Image Archives, Pacific Palisades Historical Society Collection. Accessed 12 April 2025.
[1] Jan Loomis, Pacific Palisades, Images of America Series (Mt. Pleasant, SC: Arcadia Publishing, 2009).
[2] George Fatheree, “Holding on to Altadena: Rebuilding to Preserve Housing Wealth,” Urban Land, Magazine of the Urban Land Institute, February 26, 2025. https://urbanland.uli.org/holding-on-to-altadena-rebuilding-to-preserve-housing-wealth. Accessed April 12, 2025.
[3] See for example, Paul Pringle, Alene Tchekmedyian, and Dakota Smith, “LA fire officials could have put engines in the Palisades Before the Fire Broke Out, They didn’t,” Los Angeles Times, January 14, 2025. Accessed Monday April 14, 2025. https://www.latimes.com/california/story/2025-01-14/firefighters-lafd-response-lack-of-staff-engines-pacific-palisades-fire; “Palisades Fire Information/Updates,” Pacific Palisades Community Council/. Accessed April 14, 2025. https://pacpalicc.org/index.php/palisades-fire-information-updates/.
[4] See for example: John McPhee, “The Control of Nature: Los Angeles Against the Mountains—I & II,” The New Yorker, September 26, 1988 and October 3, 1988, and Mike Davis, City of Quartz: Excavating the Future in Los Angeles (London: Verso, 1990) and Mike Davis, Ecology of Fear: Los Angeles and the Imagination of Disaster (New York: Metropolitan Books, 1998).
[5] Jeff Masters, “Climate change made deadly Los Angeles wildfires 35% more likely: new attribution study,” Yale Climate Connections, January 28, 2025. Accessed April 12, 2025. https://yaleclimateconnections.org/2025/01/climate-change-made-deadly-los-angeles-wildfires-35-more-likely-new-attribution-study/; Gavin Madakumbura et al., “Climate Change a Factor in Unprecedented LA Fires,” UCLA Sustainable LA Grand Challenge: Climate and Wildfire Research Initiative, January 13, 2025. Accessed April 12, 2025. https://sustainablela.ucla.edu/2025lawildfires.
[6] For a good overview of Los Angeles’ Landscape History, including its waterways and Indigenous histories, see Philip J. Ethington and Travis Longcore, eds., “Mapping Los Angeles Landscape History,” ArcGIS StoryMap, LA Landscape History Project. Accessed 17 April 2025. https://storymaps.arcgis.com/stories/b76cab116cbe4432a629d4791249a958. The mapping component was informed by a detailed report and work with Native American Tribal Communities. For the report, see: Ethington et al., “Historical Ecology of the Los Angeles River Watershed and Environs,” Spatial Sciences Institute, University of Southern California, June 16, 2020. Accessed 17 April 2025. https://lalandscapehistory.org/helar-final-report-16-june-2020/. See also: Nathan Masters, “The Lost Wetlands of Los Angeles,” KCET / PBS SoCal, February 29, 2012. Accessed 12 April 2025. https://www.pbssocal.org/shows/lost-la/the-lost-wetlands-of-los-angeles.
[7] On the racialized nature of American highway planning in LA and elsewhere, see for example: Eric Avila, The Folklore of the Freeway: Race and Revolt in the Modernist City (Minneapolis: University of Minnesota Press, 2014); Ryan Reft, Amanda Phillips de Lucas, and Rebecca Retzlaff, eds., Justice and the Interstate: The Racist Truth About Urban Highways (Washington, D.C.: Island Press, 2023).
[8] Ryan Reft, “Spitting Hot Fire: Malibu Wildfires and the Santa Anas,” PBS SoCal / KCET, July 11, 2013. Accessed 16 April 2025. https://www.pbssocal.org/history-society/spitting-hot-fire-malibu-wildfires-and-the-santa-anas.
[9] Paula Schiffman, “The Los Angeles Prairie,” in Land of Sunshine: An Environmental History of Metropolitan Los Angeles, edited by William Deverell and Greg Hise (University of Pittsburgh Press, 2005), 38–51.
[10] J. David Rogers, “Origins of Engineering Geology in Southern California,” Keynote Presentation, Association of Environmental and Engineering Geologists, Annual Meeting, Los Angeles, CA, September 26, 2007. Accessed 19 Jan 2025. https://web.mst.edu/rogersda/aeg50th_mtg/Origins%20of%20Eng’g%20Geology%20in%20SoCal-compressed.pdf; J. David Rogers, “Overview of Landslide Mitigation Techniques,” Slope Stability and Landslides Course, University of Wisconsin-Madison Engineering Professional Development Course, April 30, 2014. Accessed 20 Jan 2025. https://web.mst.edu/rogersda/hazard_mitigation_techniques/Rogers-Overview%20Landslide%20Mitigation.pdf. The California Highway Department also used horizontal drainage techniques to stabilize slopes in the twentieth century. See T.E. Stanton, “California experience in stabilizing earth slopes through the installation of horizontal drains by the hydrauger method,” 2nd International Conference on Soil Mechanics and Foundation Engineering (Rotterdam, 1948), International Society for Soil Mechanics and Geotechnical Engineering. Accessed 11 January 2025. https://www.issmge.org/publications/author/t-e-stanton.
[11] “A brief history of Malibu wildfires,” The Malibu Times, November 25, 2007. Accessed 16 April 2025. https://malibutimes.com/article_be86d151-e381-5db5-9a85-66cc05586070.
[12] For a good account of the Los Angeles River’s channelization, see Vittoria di Palma and Alexander Robinson, “Willful Waters,” Places Journal, May 2018. Accessed 12 Apr 2025. https://doi.org/10.22269/180508. As republished and adapted from their chapter in Thaïsa Way, ed., River Cities, City Rivers, Dumbarton Oaks Research Library, Garden and Landscape Studies Series(Cambridge, MA: Harvard University Press, 2018). See also: Jared Orsi, “Flood Control Engineering in the Urban Ecosystem,” in Land of Sunshine, op. cit., 135–151.
[13] Shawna Dark et al., “Historical Ecology of the Ballona Creek Watershed,” Southern California Coastal Water Research Project, Technical Report #671 (2011). Accessed 12 April 2025. https://ballonahe.org/downloads/non_geo_data/ballona_report[email].pdf.
[14] For the history of Los Angeles’ water supply system, see for example: William L. Kahrl, Water and Power: The Conflict Over Los Angeles’ Water Supply in the Owens Valley (Berkeley: University of California Press, 1982); Norris Hundley, Jr., The Great Thirst: Californians and Water, 1770’s to 1990’s (Berkeley: University of California Press, 1992); Donald Worster, Rivers of Empire: Water, Aridity and the Growth of the American West (New York: Pantheon Books, 1985). On the ecological transformation of Owens Lake area, see Alexander Robinson, The Spoils of Dust: Reinventing the Lake that Made Los Angeles (ORO Editions: Applied Research & Design, 2018).
[15] J. Philip Gruen and Portia Lee, “Arroyo Seco Parkway,” Historical American Engineering Record Report, HAER No. CA- 265 (1999). Accessed 14 April 2025. https://www.arroyoseco.org/HAERASP.pdf.
[16] The overall flow of water into the city in the 1940’s and 1950’s from the Owens Valley and Mono Basin according to the LA Department of Water and Power was about 300 million gallons per day. See “Los Angeles Aqueduct: Facts and History,” LADWP. Accessed 16 Apr 2025. https://www.ladwp.com/who-we-are/water-system/los-angeles-aqueduct/facts-history. For a critique of multiple other nineteenth and twentieth-century landscape projects that, like the Arroyo Seco Parkway, required the consumption and transfer of materials from far-flung locales, see Jane Hutton, Reciprocal Landscapes: Stories of Material Movements (London: Routledge, 2019).
[17] Rogers, “Origins of Engineering Geology in Southern California”; O.J. Porter, “Studies of Fill Construction Over Mud Flats Including a Description of Experimental Construction Using Vertical Sand Drains to Hasten Stabilization,” Proceedings of the First International Conference on Soil Mechanics and Foundation Engineering, Vol. 1 (Cambridge, MA: Harvard University, 1936): 229–235.
[18] Robert D. Holtz, “Sand and PV Drains—Historical Developments, Some Early Research, and Case Histories,” Geo-Congress 2019: Soil Improvement, Eighth International Conference on Case Histories in Geotechnical Engineering, https://doi.org/10.1061/9780784482117.00.
[19] When engineers first tested sand drains in marshlands in Northern New Jersey, for example, in the construction of the New Jersey Turnpike, they observed gas flaring from the ground, and in certain instances, catching fire. See: Philip C. Rutledge and Stanley J. Johnson, “Review of Uses of Vertical Sand Drains,” US Highway Research Board Bulletin (1958): 65–79 (66), https://onlinepubs.trb.org/Onlinepubs/hrbbulletin/173/173-004.pdf. On greenhouse gases emissions from roadway construction over wetlands see for example: S. Saraswati & M. Strack, “Road Crossings Increase Methane Emissions from Adjacent Peatland,” Journal of Geophysical Research: Biogeosciences 124, no. 11 (2019): 3588–3599. https://doi.org/10.1029/2019JG005246. From general wetland conversion see: Lishan Tan et al., “Conversion of coastal wetlands, riparian wetlands, and peatlands increases greenhouse gas emissions: A global meta-analysis,” Global Change Biology 26, no. 3 (March 2020): 1638–1653.
[20] Masters, “Climate change made deadly Los Angeles wildfires 35% more likely”; Madakumbura et al., “Climate Change a Factor in Unprecedented LA Fires.”
[21] For the first published use of the phrase “the Great Acceleration” to refer to the above-mentioned period see: Will Steffen et al. Global Change and the Earth System: A Planet Under Pressure (Heidelberg: Springer Nature, 2005). For its uptake by environmental historians, see for example: J. R. McNeill and Peter Engelke, The Great Acceleration: An Environmental History of the Anthropocene since 1945 (Cambridge, MA: Harvard University Press, 2015). Other writers, including Amitav Ghosh, more recently have framed the Great Acceleration as a continuation of imperial ecocide. See Ghosh, The Nutmeg’s Curse: Parables for a Planet in Crisis (Chicago: University of Chicago Press, 2021).
