My first Substack publication, The Climate Landscape, explored various themes related to our changing climate and landscape architecture to examine nature-based solutions to climate change impacts. I recently decided to shelve that particular project and focus exclusively on writing about hidden hydrology; however, a few of those early essays were worth retaining here as they showed good overlap and connections between the two topics.

There is a direct connection between our citiesโ€™ buried and lost rivers and climate change. I touched on climate here previously in this post โ€œLost Rivers for Underground Energy. It took me some time to make a direct connection between my research on climate and lost waterways until more recently, and the revelation allowed me to weave together these two passions.

Iโ€™ve continued connecting the dots and trying to build a case for the importance of historical ecology and hidden hydrology in being the locus for solutions to contemporary issues, and not just focused on nostalgia. One aspect of this is looking first at causes and effects โ€” looking back at the erasure of waterways from cities and demonstrating that the loss of ecological and hydrological systems exacerbates climate impacts such as urban heat, flooding, and sea level rise. I also looked forward to showing the patterns of historical hydrological systems that can act as frameworks for innovative climate solutions to provide adaptation and mitigation opportunities. The idea of โ€œhydrological retro-futuresโ€ is the term I chose for this backward-forward process, which allows us to connect the historical ecology to the modern metropolis and tell these stories in an engaging, visual format.

One aspect of this project is visual. By using various graphical generative AI resources like DALL-E (see image below), I have been creating speculative images of hidden hydrology in the urban context, and exploring ways that revealing, restoring, and reconnecting with lost rivers can help us imagine the potential visual impacts that could be gained. I will share more in-depth on this project and some of the interesting graphics in a later post.

Hydrologic Retrofutures: Portland Series 1 (Generated in DALL-E via prompts Jason King)

The other aspect is research and case-study-based. Brainstorming a few key topics areas, I will continue to explore here, including:

  • MICROCLIMATE COOLINGThe daylighted streams will restore ecosystem services lost when buried, such as the presence of cooling surface water and vegetation that can aid in mitigating urban heat islands.
  • FLOOD STORAGE CAPACITYDaylighting streams and springs currently in pipes will increase the capacity of infrastructure systems and make them more effective for flood resilience.
  • SEA LEVEL RISEAreas of made-land in cities as a proxy for areas of flooding due to SLR and storm surge and ways to adapt these to absorb with more resilience
  • WATER HARVESTING TO SUPPORT URBAN BIODIVERSITYDiversion of water that would be piped into uses for support of landscape vegetation and urban greening
  • WATER USE FOR COOLING ENVIRONMENTSTapping into water from subsurface water pipes to help cool cities – use in pools, water features, misters, etc.
  • WATER FOR HEATING & COOLING BUILDINGSUsing water from buried sewer pipes for heating buildings
  • PALEO VALLEYSLooking at hidden ancient river valleys as sources for groundwater recharge and storage as new aquifers

By exploring these topics, I aim to gather feedback and generate a complete toolkit of solutions that can provide designers, planners, and policy-makers with options that work in multiple climates and scales and provide cascading benefits when implemented. Iโ€™d be interested to know of other topics and solution areas out there beyond this list, as well as any case studies, writings, or research on these topics.

Below are a handful of previous stories that cover some of these topics.


ANCIENT WATERWAYS FOR COOLING CITIES

A recent article in Fast Company outlines the idea of โ€œHow ancient waterways could be tapped to cool scorching citiesโ€. The focus is on new scanning methods to reveal buried streams and โ€˜ancient waterwaysโ€™ and how to see the hidden infrastructure and potentially repurpose the water for climate change adaptation strategies. The group leading this effort is Cool City, an offshoot of the Korean Pavilion as part of the 2021 Venice Biennale, with projects using mapping underway in both Naples and Seoul. The unique idea here is to use handheld 3D scanning technology to provide more detailed scans of systems and then to use the gathered data to inform decisions for climate.

3D scanning of โ€œCasa dellโ€™Acquaโ€ Municipality of Volla (via Cool City)

Thereโ€™s merit to this as a way of approaching climate change through the use of these buried systems, both as a resource for water for irrigation and a passive cooling system and as a way to increase pipe capacity by removing underground streams through daylighting which frees up vital volume for additional stormwater management.

Mapping these has been done for many years, either as a GIS exercise with overlays of historical maps on current conditions and subsequent field verification or looking at current sewer and water and combined systems. This provides a good working system network to understand this hidden potential but not forgotten water in the city. Still, Cool City is taking it to the next level, as mentioned in the article, quoting a project collaborator, Nick De Pace, a professor of architecture and landscape architecture at the Rhode Island School of Design:

โ€œBuried streams and old waterways are not totally lost to time. Many cities have maps showing where a former creek has been shunted into an underground tunnel to make way for aboveground urban development, for example. But De Pace says many of these maps are imprecise, and the new digital scanning and mapping of the Cool City project can bring much more actionable detail to buried streams, aqueducts, and springs. By using this water to irrigate green roofs, parks, and other urban vegetation, cities can counterbalance their heat-trapping hardscapes.โ€

A low-resolution snapshot of the scan below shows how compelling this composite imagery may be, showing the spaces above and below. Does it aid in climate planning, maybe? They mention that it can be used for irrigation, for more green spaces to mitigate urban heat islands, and for having more water on the surface to reduce heat and provide more cooling. Additionally, the mix of green and blue infrastructure systems can tap into the buried water to help adapt to climate change impacts.

Composite scan of subsurface conditions (via Fast Company)

I wonder, however, how feasible it will be to scan much of the sub-surface infrastructure as proposed above by Cool City, as itโ€™s a mixed bag of small and large pipes and some more expansive and cavernous sewers, depending on the location and the era in which they were implemented. Itโ€™s a question to me if it is helpful to have 3D versions of these systems, or is mapping or modeling adequate to see the potential system components and flows and determine how it can be โ€˜tappedโ€™ to become a tool to fight climate change?

3D scanning is an excellent visualization tool, as it is often difficult to imagine what lies beneath, which is less compelling than a line on a map. As mentioned in the article, understanding the available water resources more clearly is half the battle. The next part is how to operationalize this water for climate strategies. I am interested in seeing more from Cool City, how the technology works, and what solutions come up for using hidden hydrology for climate solutions.


DETROIT: BURIED BUT NOT DEAD

Connecting the dots of Hidden Hydrology and Climate Change, a recent article makes the link between buried streams and wetlands and flood risk while investigating the inequitable distribution of risk by overlaying redlining map data. A recent article focused on Detroit dives into this connection. (โ€œBuried but not dead: The impact of stream and wetland loss on flood risk in redlined neighborhoodsโ€ by Jacob Napieralski, Atreyi Guin, and Catherine Sulich; City and Environment Interactions, January 2024.)

While tying flooding to historically buried waterways isnโ€™t novel, this is a unique idea, using mapping to overlay the Home Ownersโ€™ Loan Corporation (HOLC) maps showing redlining categories, which are well-documented spatial histories of racial and socioeconomic discrimination. The researchers used these factors (buried streams and redlining grade) as two of the criteria for flood risk along with proximity to coastal zones and intensity of vegetative cover.

Redlining Map of Detroit Metro Area (via Article)

The article is a deep dive, so I will skim on the surface with a bit on the methodology and findings, which are engaging and would be replicable anywhere using similar criteria. The mapping processes, including mapping and DEMs, were interesting. The inference of buried water bodies and flood risk has been borne out in recent events. The authors explain the connections between mapping and current flood risk:

โ€œAlthough the actual stream channel or wetland surface were buried and built upon, high resolution elevation models (e.g., LiDAR) can be used to reveal the remnants of distinct depressions from these structures, such as meandering stream valleys, in heavily urbanized landscapes. The authors assume that, although no longer occupied by active streams or wetlands, residential homes built on buried stream valleys will experience an elevated probability of flood risk not included in floodplain maps, but also that the process of burial and removal were influenced by income and race embedded in some of the racist housing policies of the 1930s and 1940s.โ€

Figure from article: โ€œAn example of a river in Southwest Detroit identified by the first United States Geological Survey (USGS) topographic map from 1905 (top left), the existing buried stream valley, as evidence from LiDAR data from 2020 (elevation units in feet above sea level), that is capped with residential development (top right), and the intense First Street Foundation Flood Factor risk of parcels near the ghost river (bottom).โ€

The flood risk data came from First Street Foundationโ€™s Flood Factor, which would be good to explore in more detail. As described, the flood risk of parcels is rated 1 to 10 based on the chance of flooding in a time interval. There were also additional criteria, as mentioned, with coastal proximity, using available data, and vegetation density using Normalized Difference Vegetation Index (NDVI) data to describe the level of vegetationโ€”more on both of these in the article, along with all the analyses.

A figure from the article showing flood risks by type of area โ€œassociated with inland, coastal zone, ghost streams, and ghost wetlands within redlined neighborhoods.โ€

The results reinforce other narratives of disproportionate risk tied to redlining districts that had more marginalized populations. The level of parcels at risk in zones C and D from the HOLC maps, although the amount of burial varied with the presence of most buried streams in HOLC Grade A & B and more buried wetlands in HOLC Grades C & D. As the authors mention:

โ€œFlood risk is disproportionately distributed, caused in part by outlawed, racist housing policies. Understanding where risk is highest can help identify optimum locations for adaptation measures to minimize flood damage in these neighborhoods.โ€

This does bring up why mapping these streams is important, and the connections to climate change, although not overt, are implied as changes in precipitation and storm intensity make flood risks more frequent and more damaging. As the authors conclude (with a nice reference to hidden hydrology (citation please), the โ€œโ€ฆrole of redlining in present day flood risk applies to cities throughout the United States, as does the importance of mapping ghost streams and wetlands to inform residents of the role โ€œhidden hydrologyโ€ may play in increasing flood risk.โ€

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SAVING SWAMPS TO SAVE OURSELVES

It was a treat to read one of my favorite authors, Annie Proulx (Swamps can protect against climate change if we only let them, New Yorker – 06.27.22), discussing wetlands and their potential for climate change protection. She includes tales of killer herons, stolen rafts, and evocative ideas on our complex relationship with swamps, noting that โ€œMany modern Americans do not like swamps, herons or no herons, and experience discomfort, irritation, bewilderment, and frustration when coaxed or forced into oneโ€ฆโ€

Illustration by Carson Ellis (via New Yorker)

Swamps were not always reviled or out of favor, as Proulx recounts, in particular the views of Henry David Thoreau, on the subject:

โ€œThoreau has been called the patron saint of swamps, because in them he found the deepest kind of beauty and interest. He wrote of his fondness for swamps throughout his life, most feelingly in his essay โ€œWalkingโ€: โ€œYes, though you may think me perverse, if it were proposed to me to dwell in the neighborhood of the most beautiful garden that ever human art contrived, or else of a Dismal Swamp, I should certainly decide for the swamp.โ€

The connection to hidden hydrology lies in the massive loss of wetlands and the subsequent loss of function to reduce carbon and the numerous ecosystem services beyond that are provided by wetlands in filtering and mediating water in our landscapes. Development in the US meant filling wetlands for farmland, pasture, and eventually cities. The swamps often were a barrier to progress and Proulx notes:

โ€œAcross the country, the ongoing stories of vile adventures in the muck made it clear to military, government, and citizenry that something had to be done about the swamps so universally detested. Everywhere there were horrendous mixtures of fen, bog, swamp, river, pond, lake, and human frustration. This was a country of rich, absorbent wetlands that increasingly no one wanted.โ€

As this occurred, there were impacts, but climate change, and sea level rise in particular, exacerbates flooding, and filled-in wetlands at the margins are poor habitats for the buildings or fields we placed on them that are now in danger of being washed away with more intense storms. There were impacts to landscapes and plantings that reduced habitat. Beyond biodiversity loss, humans will feel the overall loss of resilience more acutely. Still, it is hard to save or restore these landscapes, as Proulx notes in her story of the Black Swamp.

โ€œOne authority on water, William Mitsch, has suggested that if ten per cent of the old Black Swamp soils were allowed to become wetlands again they would cleanse the runoff, yet Ohioans remain powerfully anti-wetland. Even private efforts to restore small wetland areas are met with neighborsโ€™ complaints about noisy frogs and fears of flooding.โ€

Related are mangroves, which are also summarily destroyed, taking with them the ability to reduce storm surges and protect coastal areas in places like the Everglades. As described: โ€œMangrove swamps have been called the earthโ€™s most important ecosystem, because they form a bristling wall that stabilizes the landโ€™s edge and protects shorelines from hurricanes and erosion, and because they are breeding grounds and protective nurseries for thousands of species, including barracuda, tarpon, snook, crabs, shrimp, and shellfish. They take the full brunt of most storms and hurricanes, and generally surviveโ€”but not always.โ€

Larger, more intense hurricanes can damage mangrove areas with salt or sediment intrusion, reducing their ability to regenerate and removing their support for biodiversity. While natural disasters are a risk, development still threatens these areas despite mounting evidence of their benefits.

โ€œAlthough climate researchers see mangrove swamps as crucially important frontline defenses against rising seawater and as superior absorbers of CO2โ€”they are five times more efficient than tropical forestsโ€”they are in big trouble, and mangrove removal is a constant threat.โ€

The conclusion for Proulx is to re-establish our love of the swamp, and connect the existential threat of climate change to our ways of life to the natural systems we destroy in the process. Protecting what is there in terms of wetlands and mangroves left standing is the first goal, as well as restoring and expanding these valuable ecosystems, all of which are possible, even necessary as adaptation and mitigation strategies. Proulx ends with a call to action we can all heed:

โ€œIt is usual to think of the vast wetland losses as a tragedy, with hopeless conviction that the past cannot be retrieved. Tragic, indeed, and part of our climate-change anguish. But as we learn how valuable wetlands are in softening the shocks of the changing climate, and how eagerly the natural world responds to concerned care, perhaps we can shift the weight of wetland destruction from inevitable to โ€œnot on my watch.โ€ Can we become Thoreauvian enough to see wetlands as desirable landscapes that protect the earth while refreshing our joy in existence? For conservationists the world over, finding this joy is central to having a life well lived.โ€

Note: This post was originally posted on Substack on 12/17/24 and added to the Hidden Hydrology website on 04/22/25.

The recent essay, โ€œDaylighting a Brook in the Bronxโ€ (Pioneer Works, 10.23.24), by Emily Raboteau, focuses on a high-profile stream daylighting project from a residentโ€™s perspective. The project to daylight Tibbetts Brook has been ongoing for many years. For some quick background, Tibbetts Brook originates north of New York City in Yonkers, where it flows from Tibbetts Brook Park, heading south into the Bronx and reemerging above ground in Van Cortlandt Park. It then flows underground the remainder of the way south through the city, as demonstrated on the graphic below, showing the original course of the now-buried waterway and its eventual connection into the last leg of the Harlem River before draining into the Hudson.

Illustration of Tibbetts Brookโ€™s original course in the Bronx – via Pioneer Works

Raboteau, a resident of the Bronx, outlines the project from a personal and experiential perspective, joining some of the local advocates from the Tibbetts Advisory Group and the Parks Department and others working on the daylighting project and highlighting some of the site-based artworks focused around the brook. The positives of the project are notable, as she mentions early on in the essay:

โ€œDaylighting will abate combined sewage overflow, extend greenspace, absorb heat, and relieve chronic flooding in our areaโ€™s janky, archaic drainage system, in an act of climate mitigation and as a community effort to solve a mess caused by old crimes.โ€

Iโ€™m not planning on spending too much time recounting her specific words, which I strongly encourage you to take the time to read. I wanted to extract my reflections on a couple of critical themes she highlighted in her essay.

Perfection and Imperfection in Daylighting Projects

The challenges of these projects are myriad, and while striving for a solution that solves all the problems, trade-offs must often be made. She mentions a couple of issues, including the high cost, resistance from the MTA, and the need to underground the creek under rail lines in some industrialized portions. Additionally, gentrification could arise by โ€˜cleaning upโ€™ marginal spaces during the daylighting project. On one hand, revitalization could improve the area and attract new residents and economic activity. Conversely, the improvements could incentivize new developments and rising costs, displacing long-time residents. Another issue she brings up is the potential lack of good access from some of the adjacent neighborhoods, creating questions of ultimately who will benefit and the overall environmental justice issues at heart in any project like this. As she notes:

โ€œI had so many ethical questions without easy answers. It felt uncouth to ask them of a dream thirty years in the makingโ€ฆ. Could it ever be pleasant here? Difficult to picture. Even with the brook resurrected, there would still be the sound of the road.

I wondered: how else might the park change the neighborhood? Will it invite gentrification? Will it grow too expensive to live here? Despite the ecological and economic benefits, will anyone suffer? Can daylighting outpace inundation, or will it be rendered moot by water tables that rise with the sea? If flooding catastrophes continue, what then? Would government funds be better spent moving the most disadvantaged among us out of the watershed to higher ground? Has anyone asked for the brookโ€™s consent? Whose help is sanctioned when it comes to healing the land, and whose is rebuked?

The intersecting concerns and challenges are common in similar projects, no less complicated by threading daylighting through a dense urban center. Patience, openness, and creativity are vital, but the lack of these often results in projects never seeing the light of day. Compromises cannot come at the cost of marginalized communities. Yet, the short-sightedness of attempting to achieve โ€œperfectโ€ restoration in the form of all-or-nothing solutions is equally as damaging to attain nothing. The ability to see multiple solutions that can celebrate, reveal, and restore function requires looking beyond the ecological and including pointing a lens at the cultural context of these projects, balancing imperfection with appropriateness.

Cultural Restoration

The potential of restoration lies beyond the technical aspects and helps us fill the gaps left in implementing imperfect solutions. Raboteau mentions some of the work of artists around the brook, much of it done under the banner of the โ€œRescuing Tibbets Brookโ€ project as part of the Mary Miss-led project, City as Living Laboratory. Works mentioned include Visions of Tibbetts BrookTibbetts Estuary Tapestry, and Estuary Tattoos, all focusing on artistic and community works around the creek restoration.

Other cultural works are mentioned in the essay. Dennis RedMoon Darkeem‘s upcoming work and the planned daylighting project use harvested mugwort, an invasive species growing near the creek in Van Cortlandt Park, and weaving it into large textiles to act as sound barriers along the course of the stream corridor. She goes into more detail about two other artists. Noel Hefele and his Daylighting Tibbetts en Plein Air paintings (see below), and The Buried Brook, an augmented reality installation by Kamala Sankaram that uses a phone app to trace โ€œthe sonic geography of the buried Tibbetts Brook.โ€

Van Cortlandt Park South Bridge (via Noel Hefele)

Numerous documents and reports on the proposed $133 million project to daylight the brook can be discovered online, touching on many technical challenges. The real story is about grounding the technical with the human dimensions while highlighting the more prominent themes of hidden hydrology. Overall, the result of these cultural explorations to complement the hydrological and ecological, to Raboteau, can be revelatory:

โ€œI appreciate how initiatives like these offer an expansive response to catastrophe, a way to gather, and even a sense of hope. Itโ€™s not just the architecture of the daylighting project that interests me, the restitching at the scale of infrastructure, or the civic muscle behind the job, but the metaphysics of the exhumation. Daylighting feels like a cause for ceremony, a chance to pay respect to the body of the ghost river that flows unseen under our feet. Better yet, to imagine the perspective of the brook.โ€

Both ideas above are inherent in the conceptual potential of what can be accomplished when we think beyond just daylighting as a functional pursuit. First, we must move beyond unrealistic ideas of โ€œperfectโ€ and strive to achieve real projects that inevitably fall short of all that can be accomplished but succeed in not collapsing under the weight of being overly idealistic. Second, to achieve the first, we must continue to explore and expand our ways of engaging with lost rivers and buried creeks beyond. These include the incorporation of a continuum of solutions from the artistic to the ecological.

The recollection of the creek can be expressed metaphorically through art and soundscapes, which provide additional layers of meaning and context to the project’s more functional hydrological and ecological goals. This shows how daylighting projects, while aiming for restoration of function, are not really about attempts at pure ecological restoration but a mix of green infrastructure and ecological design aimed at multiple goals like access to nature for humans and other species, reconnecting communities, and achieving climate-positive design, among many other potentialities.

The potential of these solutions highlighted by Raboteau:

โ€œDaylighting feels like a cause for ceremony, a chance to pay respect to the body of the ghost river that flows unseen under our feet.โ€


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CONTEXTUAL CODA

Tibbetts Brook has been a topic of interest in my thinking on Hidden Hydrology for some time. I first discussed the Brook in an article on Steve Duncan, a โ€˜drainerโ€™ type of urban explorer focusing on underground and buried creeks and rivers. He has explored and photographed urban creeks around the globe, but focused on many New York City creeks, including Tibbetts Brook, as I wrote about in a post, โ€œNYC: Watercourses to Undercityโ€ (Hidden Hydrology, 12.28.17).

Tibbetts Brook, photo by Steve Duncan (via National Geographic)

Tibbetts Brook was the subject of the article โ€œWhy New York Is Unearthing a Brook It Buried a Century Agoโ€ (NY Times, 12.6.21), which discusses the project goals and objectives in detail. โ€œThe city plans to unearth the brook โ€” an engineering feat known as โ€œdaylightingโ€ โ€” at a cost of more than $130 million, because burying it in the sewer system has worsened the cityโ€™s flooding problems as a warming planet experiences more frequent and intense storms.โ€

The re-interest in the Tibbets project and connections to climate-related flooding came about as a reckoning of post-hurricane Ida solutions, which included more โ€˜spongyโ€™ green infrastructure, hardening critical infrastructure, and methods to โ€œunclog drains and widen pipes.โ€ Iโ€™ve written about Eric Sandersonโ€™s work of historical ecology and mapping hidden waterways in his Mannahatta and the broader Welikia Projects. He writes a powerful post-Ida opinion piece, โ€œLet Water Go Where It Wants to Goโ€ (NY Times, 9.28.21), where he connects the impacts of Hurricanes Sandy and Ida to areas where waterways were buried, shorelines filled, and wetlands paved over.

โ€œWater demands a place to go. That means making room for streams and wetlands, beaches and salt marshes. It means solving human-caused problems with nature-based solutions. These include removing urban impediments to let streams flow once again, a process known as daylighting; restoring wetlands and planting trees. It also means using the collective power of our community โ€” expressed through tax dollars โ€” to help people move to safer places.โ€

Overlay of flooding locations (28th Street subway station) in New York City and the location of former wetlands (The National Archives via NY Times)

In my reflection on this article by Sanderson, these connections between hidden hydrology and climate are of keen interest, so this led me to investigate in more detail one of the significant benefits espoused by those advocating daylighting Tibbetts Brook โ€” which was alluded to by Raboteau โ€” the ability to make cities more resilient to climate change by removing base flow water from buried pipes, or captured streams, through daylighting, and freeing up that water to handle extreme rainfall events and reduce flooding. As noted in the NY Times article:

โ€œThough out of sight, the brook pumps about 2.2 billion gallons of freshwater a year into the same underground pipes that carry household sewage and rainwater runoff to wastewater treatment plants. It takes up precious capacity in the outdated sewer system and contributes to combined sewer overflows that are discharged into nearby waterways.โ€

To learn more about this concept, I wrote on โ€œCaptured Streamsโ€ (Hidden Hydrology, 12.11.21), taking a deeper dive into the broader idea and its applications globally, drawing on a paper by Adam Broadhead and others, which makes the case that the encasement of freshwater streams in urban sewers is a widespread issue, significantly increases wastewater treatment costs by needlessly treating clean water and the various economic, social, and environmental benefits of diversion. The team included case studies from Zurich, highlighting efforts by the Swiss city to pioneer the idea of urban daylighting to remove base flow.

A diagram of the process, similar to the process envisioned at Tibbetts Brook, from the paper is below.

Diagram of buried stream separation from sewers in Zurich (via Broadhead et al.)

The Tibbetts Brook project aims to be a model case study in this form of separation. While the result will fulfill the goals to reduce flooding, create more resilience, and provide additional positive environmental benefits, the more significant questions Raboteau asks in her essay are vital to allow us to envision the bigger picture and redefine what counts as success: Who is included at the table in planning and design and how are those voices given appropriate weight? Who ultimately benefits? Who has access when the project is complete?

Give the essay a read, and let me know your comments.

Note: This post was originally posted on Substack on 11/30/24 and added to the Hidden Hydrology website on 04/22/25.

Stories of loss around hidden hydrology are not confined to the environmental impacts and the erasure of natural waterways. They can also include the loss of community and larger societal impacts resulting from impacts like flooding that can result from building communities that are out of balance with the larger hydrological systems they inhabit. This month is an appropriate time to remember Vanport, the community built along the Columbia River in North Portland in the early 1940s by Henry J. Keiser to house World War II shipbuilding workers, and the devastating flood on Memorial Day in May 1948 which destroyed the town.

Aerial View of Vanport, looking (OHS Research Libary, Oregon Encylopedia)

The Oregon Experience documentary from 2016, โ€œVanportโ€ is available to watch online for free and gives an in-depth history of the evolution of the community and its tragic demise. I wrote about the documentary back in 2019 in my post โ€œVanport, A Story of Lossโ€ if you want a summary of the evolution and fate of the community.

The rapid development of the community quickly made Vanport the largest wartime housing development, with over 40,000 residents, making it also the second largest city in Oregon at the time in the early 1940s. The community was built around water, nestled near the confluence of the Columbia and Willamette, with channels of the Columbia slough and smaller lakes providing amenities for residents.

Map of Vanport (Maben Manly/Oregon Encyclopedia)

I love the two images from the documentary showing the engagement with water, including an informal beach area adjacent to either Force Lake or Bayou Lake, and a group of kids near one of the sloughs.

Beach Day (Oregon Experience)
Kids on the Bayou (Oregon Experience)

There is some debate about whether the rail embankment to the west between Smith Lake and the Vanport community was meant to be a dike or protection from flooding or merely the berm for the railroad lines. For Vanport the question was irrelevant, as the waters rose quickly and breached the raised earthwork, which allowed the floodwaters to quickly inundate the entire town with a โ€œwall of waterโ€.

The devastation was compounded by the location within the historical Columbia River floodplain and the ephemeral nature of the construction which was rapid and not meant to be long-lived. Other breaches occurred and the entire area inland became a lake. The images, such as below, of houses floating amid the floodwaters, hint at the lack of solid foundations.

Houses floating after the flood (Oregon Encyclopedia)

The devastation was immense and swift, leaving behind the wreckage of the community. Over time the debris was cleared and new uses emerged to erase the remnants of the Vanport community, as it is now part of the Portland Expo Center, Heron Lakes Golf Club, Portland International Raceway, and adjacent industrial development.

Post-flood destruction of Vanport (Portland City Archives, Portland State University)

Vanport was never meant as a permanent community, and the occupation of the site continued well after shipbuilding activities had wound down following the war, providing a refuge for residents who found barriers to housing elsewhere. The suddenness of the destructive forces, the lack of warning and accountability to residents about the dangers of the flooding, and the displacement of numerous residents who became refugees overnight due to the disaster. These compounding forces give this site and its history special meaning for Portanders and the need to discuss, remember, and confront our histories, with lessons to be shared with other communities. The fact that the Vanport has been physically erased from the map also led to its erasure from our memory. It is the same as the burial and erasure of streams, and wetlands, and deserves the same attention to the ecological, hydrological, and cultural forces at work.

The legacy continued with displacement, as a product of racial housing discrimination led to difficulty for groups to find other housing. As mentioned by Abbott in the Oregon Encyclopedia entry:

โ€œRefugees crowded into Portland, a city still recovering from the war. Part of the problem was race, for more than a thousand of the flooded families were African Americans who could find housing only in the growing ghetto in North Portland. The flood also sparked unfounded but persistent rumors in the African American community that the Housing Authority had deliberately withheld warnings about the flood and the city had concealed a much higher death toll.”

It also is important to consider the vulnerability that still exists today. While the installation of Columbia River dams provides some moderation of flood levels that didnโ€™t exist in the 1940s, and the bolstering of true levees and dikes meant to protect from future floods, risks persist along the waterโ€™s edge. This protection is aided today through efforts such as Levee Ready Columbia, working to protect from flood risk in the context of development and climate change in the slough.

Vanport Mosaic

As a reminder of our history and place, additional resources provide the background of life at Vanport and the people who called it home for a brief time. This video โ€œVanport: Legacy of a Forgotten Cityโ€, below, is worth checking out for more context about the community and the work being done to keep the memory alive. The video is part of a great resource, Vanport Mosiac, which calls itself โ€œโ€ฆa memory-activism platform. We amplify, honor, and preserve the silenced histories that surround us in order to understand our present, and create a future where we all belong.โ€

Their annual Vanport Mosaic Festival is upcoming this year from May 18 to June 1, 2024, which features speakers, tours, and events on-site and at nearby community venues (program here). Iโ€™d recommend taking the bus tour (if they still offer it) to see parts of the site not accessible outside of festival hours around the original Vanport community. I wrote an extensive post about the festival and tour in June 2019 โ€œVanport Mosaicโ€ and they were kind enough to provide a link to it on their site for others to access.

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Note: This post was originally posted on Substack on 05/15/24 and added to the Hidden Hydrology website on 04/23/25.

The idea of Detroitโ€™s Ghost streams work bridges my two interests by connecting the dots of Hidden Hydrology and Climate Change, a topic that I will revisit often. The post discusses research in Detroit, Michigan, that connects buried streams and flood risks, using historical ecological information overlaid with redlining map data to show the potential negative impacts on historically marginalized communities.

A recent podcast โ€œWhat We Can Learn from Ghost Streams.โ€ (Next City, 05.01.24) talked about Bruce Willenโ€™s work on Baltimoreโ€™s Ghost Streams, as well as the work in Detroit, featuring the research of Jacob Napieralski, a professor of Geology at the University of Michigan-Dearborn. Give the podcast a listen, and as a good companion, he also goes into more depth about this work in Detroit in this article โ€œHow ghost streams and redliningโ€™s legacy lead to unfairness in flood risk, in Detroit and elsewhere.โ€ (The Conversation, 03.19.24)

The basis of the research is what are known as โ€˜redliningโ€™ maps. For a little background, the Home Ownersโ€™ Loan Corporation (HOLC) was a government agency created to assess financial risk for mortgage lending for real estate. The tool was used to systematically institutionalize racist policies in cities around the United States by assessing areas inhabited by people of color, poor, and immigrants as much higher risk than those where rich, white residents lived. The process led to disproportionate investment in low-risk neighborhoods and marginalization in those deemed โ€˜hazardousโ€™ or โ€˜high-riskโ€™ zones, which ultimately created concentrated areas of poverty through a lack of economic opportunities. The redlining has become a shorthand for the inequity of communities, and mapping allows for looking at how these historical impacts persist in cities today.

Detroit Redlining Map (The Conversation)

The research overlays these maps with other data to extract how the legacy of racist home lending in the past has created more risk of impacts like flooding today. The goal of the study was โ€œโ€ฆ to determine whether a history of waterway burial and/or redlining influenced the overall flood risk of communities today.โ€ The data revealed that the burial of streams and wetlands did impact current risks in the historically marginalized communities. As Napieralski mentions in the podcast:

โ€œFlood risk is very intricately linked to history, and by ignoring history we may be missing some clues that help us move forward.โ€

Rather than dwell on the negative, the authors mention the positive side of the analysis, noting that most communities have this data and that it can be useful in focusing on where best to employ solutions like green infrastructure or nature-based design solutions, saying: โ€œIf communities want to protect residents from flooding, itโ€™s crucial for them to map and understand their โ€œhidden hydrology.โ€

Buried But Not Dead

More in-depth exploration of the research is found in the journal article โ€œBuried but not dead: The impact of stream and wetland loss on flood risk in redlined neighborhoods.โ€ (City and Environment Interactions, January 2024). The study was authored by Napieralski along with Atreyi Guin, and Catherine Sulich, and their research outlines the mapping to overlay the Home Ownersโ€™ Loan Corporation (HOLC) maps showing redlining categories, using buried streams and redlining grades to estimate flood risk. The mapping processes were interesting, including the use of historical documents and Digital Elevation Models (DEMs) to infer buried water bodies and flood risk:

โ€œAlthough the actual stream channel or wetland surface were buried and built upon, high resolution elevation models (e.g., LiDAR) can be used to reveal the remnants of distinct depressions from these structures, such as meandering stream valleys, in heavily urbanized landscapes. The authors assume that, although no longer occupied by active streams or wetlands, residential homes built on buried stream valleys will experience an elevated probability of flood risk not included in floodplain maps, but also that the process of burial and removal were influenced by income and race embedded in some of the racist housing policies of the 1930s and 1940s.โ€

Mapping Analyses of Buried Streams and Filled Wetlands and Flood Risk (City and Environment Interactions)

Using data from First Street Foundationโ€™s Flood Factor, the flood risk of parcels is rated 1 to 10 based on the chance of flooding in a time interval There were also additional criteria that were integrated into risks associated with different types of impact, sorted by HOLC grade. As the authors mention: โ€œFlood risk is disproportionately distributed, caused in part by outlawed, racist housing policies. Understanding where risk is highest can help identify optimum locations for adaptation measures to minimize flood damage in these neighborhoods.โ€

Figure from the article, showing flood risks by type of area โ€œassociated with inland, coastal zone, ghost streams, and ghost wetlands within redlined neighborhoods.โ€

This does bring up why mapping these streams and wetlands is important. They provide a basis for analysis by using other data as cross-sectional overlays, unlocking connections between impacts that may, on the surface, be unseen. The connections of this work to climate change, of which flooding is a key impact, are clear, as changes in precipitation and storm intensity make flood risks more frequent and more damaging. The authors conclude the

โ€œ[The]โ€ฆrole of redlining in present-day flood risk applies to cities throughout the United States, as does the importance of mapping ghost streams and wetlands to inform residents of the role โ€œhidden hydrologyโ€ may play in increasing flood risk.โ€

Thanks for reading Hidden Hydrology! Subscribe for free to receive new posts and support my work.

Note: This post was originally posted on Substack on 05/08/24 and added to the Hidden Hydrology website on 04/23/25.