Editor\u2019s 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<\/a> 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<\/a>. In addition, check here<\/a> for information on the conference, including accommodations.<\/strong><\/p>\n By Charlotte Leib<\/em><\/p>\n Los Angeles is a city of roads. It wasn\u2019t always that way. In the 1920\u2019s, when Los Angeles residents first brought their Model T\u2019s 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\u2019s atop of 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. Around the road, during the 1930\u2019s, sprouted the modest homes and garden bungalows of the Pacific Palisades. By the 1960\u2019s, more extravagant residences began to appear. The neighborhood quickly transformed into a preferred retreat for some of LA\u2019 most affluent homeowners.[1]<\/a><\/p>\n In January 2025, during the Pacific Palisades Wildfire, the majority of the neighborhood that had developed from the 1920\u2019s onward around the Via de la Paz went up in flames.<\/p>\n 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, the Eaton Fire consumed portions of the neighborhood that had been developed by and for Black homeowners and renters in the wake of the 1968 Fair Housing Act, which prohibited housing discrimination on the basis of race, religion, sex, or national origin. In the decades that followed, Altadena became a haven for Black Angelenos\u2014until it burned.[2]<\/a><\/p>\n Over the course of Los Angeles\u2019 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\u2019s Pacific Palisades neighborhood and, simultaneously, much of LA\u2019s 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.<\/p>\n If the most popular contemporary approaches to environmental planning in Los Angeles and at the planetary scale have one common trait, it\u2019s 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 <\/em>series \u201cThe Control of Nature: Los Angeles Against the Mountains,\u201d and as Mike Davis has shown in his work, LA\u2019s urban history is a case in point for how technological fixes adopted in response to the city\u2019s recurrent landslides, fires, and floods have never really worked. As Davis has highlighted\u2014and in a lesson that should resonate far beyond California and into contemporary environmental planning and climate change policy circles\u2014techno-fixes like flood control, hillside stabilization, and the practice of building back better after fires have merely deepened Los Angeles\u2019 economic and racial inequalities over the course of the city\u2019s history.[3]<\/a><\/p>\n It would be an oversight not to recognize how a similar techno-optimism shapes many private and public entities\u2019 current stance toward the climate crisis. For the Earth\u2019s techno-optimists, be they individuals, businesses, or governments, carbon-capture and geoengineering technologies are held up as salvos for the crisis at hand\u2014the very same crisis that made the LA fires of this past January 2025 so severe.[4]<\/a><\/p>\n Still, the commentators who pointed to the Pacific Palisades\u2019 roadways as one cause for the severity of the Palisades Fire in particular were not entirely wrong. LA\u2019s roadway infrastructure did <\/em>contribute to the severity of the destructive wildfire\u2014just not in the way critics imagined.<\/p>\n Before Los Angeles\u2019 landscape evolved into an intricate tapestry of roads, grids, and freeways, significant portions of the city hosted extensive wetlands.[5]<\/a> Yes, Los Angeles had wetlands. And by and large, roadways ruined them.<\/p>\n As this photo essay will reveal, LA\u2019s 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\u2019s transformation into a sprawling megalopolis.[6]<\/a> The city\u2019s 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.<\/p>\n Los Angeles\u2019 roads have contributed to climate change not only for the obvious ways in which they\u2019ve encouraged the extraction and consumption of petroleum-derived fuels. They\u2019ve also contributed to climate change in the way they\u2019ve required the drying-out of millions of cubic-feet of soil\u2014soil that, were it still wet, would do much to moderate the severe wildfire events that will continue to reshape the city\u2019s urban landscape and livability in this century.<\/p>\n To be sure, Los Angeles was a fire-prone city long before roadways and urban development overtook the city\u2019s wetlands. As Ryan Reft noted in a 2013 KCET article<\/a>, sizeable areas throughout Los Angeles County experienced fires in 1930, 1935, 1943, 1956, 1961, 1966-67, 1970, 1978, 1982, 1985, 1993, 1996, and 2007.[7]<\/a><\/p>\n Centuries before these fires, wildfire events were integral parts of Los Angeles\u2019 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\u2019 fire-prone woodlands, grasslands, and chaparral.[8]<\/a> In 1932, after a landslide collapsed a portion of one of the Pacific Palisades\u2019 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\u2019s slide-prone clay seam. It was one of the first of many twentieth-century schemes to control of Los Angeles\u2019 turbulent terrain, attempts that culminated in failure.<\/p>\n Hill\u2019s 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\u2019s 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\u2019s clay seam.<\/p>\n 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.[9]<\/a><\/p>\n Engineers continued to manipulate Los Angeles\u2019 soil and hydrology throughout the twentieth century with ambitious, if ineffective, land stabilization schemes like Hull\u2019s. Flood control projects further limited the amount of water returning to Los Angeles\u2019 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\u2014and in many cases, acute disasters.<\/p>\n The Los Angeles River\u2019s currently channelized banks are perhaps the most iconic evidence of this truism. In 1938, just years after LA\u2019s massive 1930 Decker Canyon 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.[10]<\/a><\/p>\n 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\u2019s natural flow into a concrete coffin.[11]<\/a><\/p>\n From the 1920\u2019s through the 1940\u2019s, 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\u2019s 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\u2019s 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\u2019s, and more dramatically in the 1940\u2019s after USACE channelized the Creek and transformed the surrounding intertidal wetlands and vernal pools into a docking marina and developable land.[12]<\/a><\/p>\n Ballona Creek\u2019s channelization prepared the way for more highways, more roads, more houses\u2014and for developers and city tax rolls, more profits. As the wetland was purposefully dried up and channelized, Los Angeles\u2019 unrelenting demand for water simultaneously transformed the semi-arid Owens Valley and the nearby Mono Basin into manufactured deserts.[13]<\/a> We often think of LA\u2019s 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\u2019s wetlands. The city\u2019s 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.[14]<\/a><\/p>\n The Arroyo Seco Parkway did more than just bury and ruin a creek that had once freely replenished LA\u2019s lowlands with moisture, however. Like the garden bungalows that were simultaneously budding across Los Angeles in the 1940\u2019s and 1950\u2019s, the landscaped parkway required water. Although city officials named the parkway after a dry creek, they intended it to be surrounded by green growth\u2014growth that required irrigation and the further desertification of the beleaguered Owens Valley and Mono Basin.[15]<\/a><\/p>\n During the middle decades of the twentieth century, Los Angeles\u2019 urban expansion onto its wetlands not only reduced the amount of moisture flowing back into the city\u2019s atmosphere. The very presence of new, heavy structures atop former wetlands caused parts of the city\u2019s already tectonically-active landscape to subside.<\/p>\n The problem was particularly severe at the Port of Los Angeles. In a concentric pattern, from 1928 to 1965, portions of the area around the U.S. Naval Base and the port\u2019s piers and storage yards subsided from depths of two to as much as 28 feet.<\/p>\n 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\u2013Oakland Bay Bridge over marshland from 1933 to 1936. Concurrently, in the 1940\u2019s through 1960\u2019s, 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.[16]<\/a><\/p>\n The technology, that of the sand drain, served as yet another means through which to desiccate LA\u2019s wetlands. All throughout the twentieth century, at LA\u2019s port and beyond, geotechnical engineers issued plans that popularized the technology\u2019s use.[17]<\/a><\/p>\n 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\u2014spillover technology from the oil and gas industry\u2014construction 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\u2019s high permeability, water then flows upward through the sand columns and away from the construction site over the sand blanket.<\/p>\n Quietly yet significantly, the global use of sand drain technology has also contributed to climate change\u2014the very circumstance that has made LA\u2019s recent fires so unprecedented and deadly.<\/p>\n Although it was not widely known when sand drains were first invented and used, cutting up wetlands with sand drains\u2014essentially transforming them into metaphorical blocks of Swiss cheese\u2014hastens the release of potent greenhouse gases into the atmosphere. Methane, nitrous oxide, and carbon dioxide\u2014all drivers of atmospheric warming\u2014are often released in the process of installing sand drains and compressing the surrounding soils.[18]<\/a><\/p>\n Climate scientists have recently foregrounded how the historic combustion of coal, oil, and natural gas exacerbated LA\u2019s recent fires.[19]<\/a> But on a local scale, it\u2019s important to also account for the technologies that have reconfigured Los Angeles\u2019 surface when we consider the factors that made the fires so severe.<\/p>\n Concretized channels, gargantuan freeways and sand drains enabled the purposeful desiccation of the city\u2019s formerly seasonally-wet marshes, flood plains, 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.<\/p>\n Both Los Angeles\u2019 history and that of the world\u2019s in the twentieth century would be incomplete without reference to the Great Acceleration. It\u2019s a term that\u2019s been used since the early 2000\u2019s by environmental historians and earth systems scientists to frame the period during and after World War II when the world\u2019s 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.[20]<\/a><\/p>\n The gas-powered blowers, channelized rivers, and sand-drained ports and freeways detailed in this post all contributed to the Great Acceleration. They sped up nature\u2019s time\u2014the pace of life that had for entire geological epochs governed Los Angeles\u2019 geological and terrestrial transformation\u2014and sapped crucial moisture from LA\u2019s above-ground and subterranean environments in the process.<\/p>\n To truly know the factors that combined to cause the Great Acceleration and the climatic conditions that exacerbated the intensity of LA\u2019s recent fires requires attending to the landscapes that Los Angeles lost in the twentieth century. Chief among those losses were the city\u2019s wetlands.<\/p>\n 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\u2019s wetlands and grasslands into haying fields to feed and fuel their oxen, mules, and horses. These were the animals that graded LA\u2019s first roads and that surveyors used to lay out the streets of the recently charred and devastated Pacific Palisades.<\/p>\n 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.<\/p>\n 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\u2019t just be carbon emissions we track, or global temperature rise. We have to account for transformations in local landscapes. That\u2019s the power of urban landscape history. It\u2019s a field of inquiry that reveals not just how cities and landscapes transform, but why cities like Los Angeles burn\u2014and why it might just be another misguided techno-fix to try to change that.<\/p>\n Charlotte Leib<\/a>\u00a0is 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\u00a0the nineteenth and twentieth centuries. Her prior knowledge of Los Angeles\u2019 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.<\/em><\/p>\n Featured image (at top): \u201cEaster Sunrise Services on Peace Hill in Pacific Palisades<\/a>,\u201d 1922, photographic print. Santa Monica Public Library Image Archives, Pacific Palisades Historical Society Collection. Accessed 12 April 2025<\/strong><\/p>\n [1]<\/a> Jan Loomis, Pacific Palisades<\/em>, Images of America Series(Mt. Pleasant, SC: Arcadia Publishing, 2009).<\/p>\n [2]<\/a> George Fatheree, \u201cHolding on to Altadena: Rebuilding to Preserve Housing Wealth,\u201d Urban Land<\/em>, Magazine of the Urban Land Institute, February 26, 2025. https:\/\/urbanland.uli.org\/holding-on-to-altadena-rebuilding-to-preserve-housing-wealth<\/a>. Accessed April 12, 2025.<\/p>\n [3]<\/a> See for example: John McPhee, \u201cThe Control of Nature: Los Angeles Against the Mountains\u2014I & II,\u201d The New Yorker<\/em>, September 26, 1988 and October 3, 1988, and Mike Davis, City of Quartz: Excavating the Future in Los Angeles<\/em> (London: Verso, 1990) and Mike Davis, Ecology of Fear: Los Angeles and the Imagination of Disaster<\/em> (New York: Metropolitan Books, 1998).<\/p>\n [4]<\/a> Jeff Masters, \u201cClimate change made deadly Los Angeles wildfires 35% more likely: new attribution study,\u201d Yale Climate Connections<\/em>, 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\/<\/a>; Gavin Madakumbura<\/strong> et al., \u201cClimate Change a Factor in Unprecedented LA Fires,\u201d UCLA Sustainable LA Grand Challenge: Climate and Wildfire Research Initiative<\/em>, January 13, 2025. Accessed April 12, 2025. https:\/\/sustainablela.ucla.edu\/2025lawildfires<\/a>.<\/p>\n [5]<\/a> For a good overview of Los Angeles\u2019 Landscape History, including its waterways and Indigenous histories, see Philip J. Ethington and Travis Longcore, eds., \u201cMapping Los Angeles Landscape History,\u201d ArcGIS StoryMap, LA Landscape History Project. Accessed 17 April 2025. https:\/\/storymaps.arcgis.com\/stories\/b76cab116cbe4432a629d4791249a958<\/a>. The mapping component was informed by a detailed report and work with Native American Tribal Communities. For the report, see: Ethington et al., \u201cHistorical Ecology of the Los Angeles River Watershed and Environs,\u201d Spatial Sciences Institute, University of Southern California, June 16, 2020. Accessed 17 April 2025. https:\/\/lalandscapehistory.org\/helar-final-report-16-june-2020\/<\/a>. See also: Nathan Masters, \u201cThe Lost Wetlands of Los Angeles,\u201d KCET \/ PBS SoCal<\/em>, February 29, 2012. Accessed 12 April 2025. https:\/\/www.pbssocal.org\/shows\/lost-la\/the-lost-wetlands-of-los-angeles<\/a>.<\/p>\n [6]<\/a> 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<\/em> (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 <\/em>(Washington, D.C.: Island Press, 2023).<\/p>\n [7]<\/a> Ryan Reft, \u201cSpitting Hot Fire: Malibu Wildfires and the Santa Anas,\u201d PBS SoCal \/ KCET<\/em>, July 11, 2013. Accessed 16 April 2025. https:\/\/www.pbssocal.org\/history-society\/spitting-hot-fire-malibu-wildfires-and-the-santa-anas<\/a>.<\/p>\n [8]<\/a> Paula Schiffman, \u201cThe Los Angeles Prairie,\u201d in Land of Sunshine: An Environmental History of Metropolitan Los Angeles<\/em>, edited by William Deverell and Greg Hise (University of Pittsburgh Press, 2005), 38\u201351.<\/p>\n [9]<\/a> J. David Rogers, \u201cOrigins of Engineering Geology in Southern California,\u201d 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\u2019g%20Geology%20in%20SoCal-compressed.pdf<\/a>; J. David Rogers, \u201cOverview of Landslide Mitigation Techniques,\u201d 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<\/a>. The California Highway Department also used horizontal drainage techniques to stabilize slopes in the twentieth century. See T.E. Stanton, \u201cCalifornia experience in stabilizing earth slopes through the installation of horizontal drains by the hydrauger method,\u201d 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<\/a>.<\/p>\n [10]<\/a> \u201cA brief history of Malibu wildfires\u201d The Malibu Times, November 25, 2007. Accessed 16 April 2025. https:\/\/malibutimes.com\/article_be86d151-e381-5db5-9a85-66cc05586070<\/a>.<\/p>\n [11]<\/a> For a good account of the Los Angeles River\u2019s channelization, see Vittoria di Palma and Alexander Robinson, \u201cWillful Waters,\u201d Places Journal<\/em>, May 2018. Accessed 12 Apr 2025. https:\/\/doi.org\/10.22269\/180508<\/a>. As republished and adapted from their chapter in Tha\u00efsa Way, ed., River Cities, City Rivers<\/em>, Dumbarton Oaks Research Library, Garden and Landscape Studies Series(Cambridge, MA: Harvard University Press, 2018). See also: Jared Orsi, \u201cFlood Control Engineering in the Urban Ecosystem,\u201d in Land of Sunshine<\/em>, op. cit., 135\u2013151.<\/p>\n [12]<\/a> Shawna Dark et al., \u201cHistorical Ecology of the Ballona Creek Watershed,\u201d 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<\/a>.<\/p>\n [13]<\/a> For the history of Los Angeles\u2019 water supply system, see for example: William L. Kahrl, <\/strong>Water and Power: The Conflict Over Los Angeles\u2019 Water Supply in the Owens Valley<\/em> (Berkeley:\u00a0 University of California Press, 1982); Norris Hundley, Jr., The Great Thirst: Californians and Water, 1770\u2019s to 1990\u2019s <\/em>(Berkeley: University of California Press, 1992); Donald Worster, Rivers of Empire: Water, Aridity and the Growth of the American West<\/em> (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<\/em> (ORO Editions: Applied Research & Design, 2018).<\/p>\n [14]<\/a> J. Philip Gruen and Portia Lee, \u201cArroyo Seco Parkway,\u201d Historical American Engineering Record Report<\/em>, HAER No. CA- 265 (1999). Accessed 14 April 2025. https:\/\/www.arroyoseco.org\/HAERASP.pdf<\/a>.<\/p>\n [15]<\/a> The overall flow of water into the city in the 1940\u2019s and 1950\u2019s from the Owens Valley and Mono Basin according to the LA Department of Water and Power was about 300 million gallons per day. See \u201cLos Angeles Aqueduct: Facts and History,\u201d LADWP<\/em>. Accessed 16 Apr 2025. https:\/\/www.ladwp.com\/who-we-are\/water-system\/los-angeles-aqueduct\/facts-history<\/a>. 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 <\/em>(London: Routledge, 2019).<\/p>\n [16]<\/a> Rogers, \u201cOrigins of Engineering Geology in Southern California\u201d; O.J. Porter, \u201cStudies of Fill Construction Over Mud Flats Including a Description of Experimental Construction Using Vertical Sand Drains to Hasten Stabilization,\u201d Proceedings of the First International Conference on Soil Mechanics and Foundation Engineering<\/em>, Vol. 1 (Cambridge, MA: Harvard University, 1936): 229\u2013235.<\/p>\n [17]<\/a> Robert D. Holtz, \u201cSand and PV Drains\u2014Historical Developments, Some Early Research, and Case Histories,\u201d Geo-Congress 2019: Soil Improvement<\/em>, Eighth International Conference on Case Histories in Geotechnical Engineering, https:\/\/doi.org\/10.1061\/9780784482117.00<\/a>.<\/p>\n [18]<\/a> 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, \u201cReview of Uses of Vertical Sand Drains,\u201d US<\/em> Highway Research Board Bulletin<\/em> (1958): 65\u201379 (66), https:\/\/onlinepubs.trb.org\/Onlinepubs\/hrbbulletin\/173\/173-004.pdf<\/a>. \u00a0On greenhouse gases emissions from roadway construction over wetlands see for example: S. Saraswati & M. Strack, \u201cRoad Crossings Increase Methane Emissions from Adjacent Peatland,\u201d Journal of Geophysical Research: Biogeosciences<\/em> 124, no. 11 (2019): 3588\u20133599. https:\/\/doi.org\/10.1029\/2019JG005246<\/a>. From general wetland conversion see: Lishan Tan et al., \u201cConversion of coastal wetlands, riparian wetlands, and peatlands increases greenhouse gas emissions: A global meta-analysis,\u201d Global Change Biology<\/em> 26, no. 3 (March 2020): 1638\u20131653.<\/p>\n![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/04_1880s_santa-monica_mountains_inlet.jpg?w=768\")
<\/strong>
Yet beginning in the 1920\u2019s and 1930\u2019s, the construction of ambitious engineering projects across LA County, mainly designed to ease automobile transport by road, began to radically alter the city\u2019s 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\u2019s newly-built roads.<\/p>\n![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/12_subsidence_port-of-la.jpg?w=1024\")
![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/13_tg-2755_13-9.jpg?w=1024\")
<\/strong>Sand drain technology\u2019s objective is to free water from the land, and make it go away. Since the 1930\u2019s when the technology was first developed by engineers at the California Division of Highways\u2019 Materials and Research Department, it has served as one of the most powerful ways to make a wetland disappear.<\/p>\n![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/14_sand-drain-diagram-full.jpg?w=1024\")
![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/15_sand-drain-diagram-crop-blue.jpg?w=1024\")
<\/figure>\n<\/div>\n![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/17_1902_ballona-lagoon_man-wades_usc.jpeg?w=1024\")
\n![\"\"](\"https:\/\/themetropole.blog\/wp-content\/uploads\/2025\/05\/headshot_2024_wide_01.jpg?w=1024\")
<\/figure>\n<\/div>\n