Category: case study

Frog Taxis & Wildlife Ways

Jason Kingcase study, ecology, habitat, lakes, landscape, oregon, places, portland, rivers, watersheds, wetlandsLeave a Comment on Frog Taxis & Wildlife Ways

In Northwest Portland, Oregon, red-legged frogs living in Forest Park face a dangerous commute in the fall and winter, traversing from their upland homes down to the spawning grounds adjacent to the Willamette River. The species typically is found in conifer hardwood forests that have an aquatic-terrestrial connection to ponds and wetlands as part of their life cycles.

Northern Red-legged Frog

The degree of landscape changes inherent over time is seen in a series of maps spanning the previous century and a half of urbanization, centered near present-day Harborton, the location of a critical habitat connection for the frogs. From the original surveys in the 1850s, the area was lightly developed, and the areas noted as “Timber, Fir, Cedar, Maple, Hemlock, Yew, etc.” showing the zones that would become modern Forest Park and the uninterrupted upland to lowland connections along the Willamette River.

1855 General Land Office Survey Map (via BLM)

By the 1900s and the mapping from the USGS Topographic Survey, some development was happening along the water in the early town of Linnton, and the rail lines were built that started to sever these historical ecological connections.

1897 USGS Topographic Survey (via TopoView)

The current aerial image shows the clear line marking upland to lowland as separated by roadways and more impervious industrial development located along the Willamette River, reducing the amount of shoreline habitat.

2024 Aerial Image (via Google Earth)

The historical upland to lowland conditions has been radically disturbed along the entire margin of Forest Park. We could infer from the series of maps that historically, the frogs had significantly more habitat options along a much larger zone (and even more if you look at maps south of here showing additional lakes and wetlands), and that over time, a series of human-made linear barriers (railroad, roads) and urbanization cut off connections while reducing overall shoreline habitat. This ultimately resulted in a severe decline in several species populations, including the red-legged frogs.

As you see from a zoomed-in area, the major impediment for the frogs is a gauntlet, including a four-lane Highway 30, another smaller side road, and railroad tracks that prevent frogs from safely accessing the breeding area around the Willamette. Described by many as a real-life game of Frogger, the result is documented mass killings of frogs that attempt migration to these zones in rainy seasons.

Frogger (via Atari Age)

As a response to the negative impacts of the species, an intrepid group of volunteers has implemented what they call the Frog Taxi. Starting in 2013, as documented on the site Linnton Frogs, the group has mobilized annually to collect frogs from Forest Park, transporting them across Highway 30 and other roads and railroad tracks to get to the breeding around along the Willamette, and then relocating them back across the roadway to the upland. You can see some stats of the group’s work from 2013-2021. The work has continued, and Oregon Field Guide recently did a story on this year’s Frog Taxi, which provides a great overview of the process the volunteers undertake to save this remnant population of red-legged frogs.

Taxi to Where?

Making it across the barrier alone or via taxi only solves one part of the equation. To fully connect the life cycle, viable habitat conditions need to be provided for suitable breeding conditions on the waterside. The landscape of the entire edge of the area used to include the multiple connected ecosystems lakes along a long riverfront edge, including Guild’s, Kitteridge’s, and Doane’s, which is notable as their surrounding wetland margins have been impacted.

Once the frogs can reach the site, the original habitat must be restored to provide suitable conditions. Currently owned by PGE, the taxi “drop-off’“ site is the locus of additional restoration efforts, as noted from the PGE site related to the Harborton Habitat Project:

“The site is one of the largest known breeding grounds for northern red-legged frogs, an amphibian species classified as “sensitive” by the state of Oregon and a “species of concern” under Federal listing status. Additionally, the property is situated where the Willamette River meets Multnomah Channel – a perfect spot for juvenile salmon to rest and find food on their way to the Pacific Ocean.”

Harborton Habitat Restoration (via PGE)

The overall goal is to move from taxi service to more uninterrupted connections from the upland forest to the pools to eliminate the game of Frogger, as well as eliminate the need for volunteers to fill the role of taxi drivers. The next iteration involves increasing overall habitat mobility through an amphibian tunnel that will funnel the frogs along the edges and allow them to move under the roadways and rail lines, connecting Forest Park directly to Harborton. As noted, the Harborton Frog Crossing Project proposed this new connection:

“In an effort to save the dwindling frog population, local wildlife officials and the Oregon Wildlife Foundation have proposed to build a highway underpass to grant the amphibians safe passage. The project calls for a concrete culvert beneath Northwest St. Helens Road and Marina Way to help the frogs reach their preferred breeding grounds.”

Other studies are helping pinpoint more specifics related to the locations and magnitude of the problem. There is funding to assess the mortality of the frog populations is underway by Northwest Ecological Research Institute (NERI), and funded by the Oregon Conservation & Recreation Fund Projects and the Oregon Zoo. The specific goals hope to inform the amphibian tunnel, as they state:

“A wildlife undercrossing and/or creating improved wetland spaces that do not require road crossings are the primary proposed solutions. These are expensive, infrastructure-based solutions, and more data is required to find the most appropriate path forward. Specifically, increased data on the rate and location of frogs being killed at road crossings will inform timing and movement patterns to find the best solution.”

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Wildlife Ways

The Oregon Wildlife Corridor Action Plan (ODFW, January 2024) notes that there are naturally occurring barriers to wildlife movement, but the most critical are human-caused barriers that block movement. Within the context, they also discuss how barriers are relative to species, as quoted:

“The most readily apparent human-caused barriers to animal movement are the physical structures that impede or outright prevent connectivity, such as buildings, fences, roadways, solar developments, and dams. The response of wildlife to structures varies by structure type and by species. For example, a fox may be able to make its way around a large industrial complex, whereas for a frog the complex might represent an impassable barrier. While not all physical structures will completely block animal movement, these features are often associated with increased risk of mortality for wildlife due to collisions, entanglement, entrapment, and persecution. Two of the most prevalent physical impediments to wildlife connectivity are roadways and fencing.”

Wildlife crossings, in general, are gaining momentum with various overpass and underpass options that direct and funnel species from habitat areas and provide safe passage through dangerous areas. The focus is often on larger species, specifically deer and elk, here in Oregon, moving between fragmented parcels of land. There is also the potential to reduce vehicle-wildlife collisions, with specific action plans to provide more solutions. These are dynamic opportunities to connect large habitat patches but come at a steep price.

Wildlife Crossing (via Caltrans)

The types of crossings also need to be adapted to the species’ needs. My favorite is the Crab Bridge on Christmas Island in Australia, which provides an almost vertical climb and spans over a roadway to facilitate the migration of red crabs.

Crab Bridge (via Christmas Island National Park)

Another analog is the work being done for fish passage, including strategies for repairing culverts to provide better access for fish, installing tidal gates to better allow movement up and downstream in fluctuating water cycles and implementing fish screens to limit access to certain waterways while providing access to certain areas necessary for the species to thrive. These are less visible than the larger wildlife connections; however, they also come at a significantly smaller cost and can be localized to specific species migration corridors.

The amphibian connections are a microcosm of these types of projects. More modest in scale, but growing in popularity, there are numerous examples around the globe of different types of passages that work for different amphibian species. The hope is that these will continue to do some of the necessary repair work for the severed connections between critical hydrological habitats, hopefully helping the Harborton Red-Legged Frog populations survive and thrive and give the taxi drivers a break.

Amphibian Crossing example from Doñana National Park, Spain (via Research Gate)

If you are aware of other examples of strategies being used to allow amphibians or other species to facilitate movement in fragmented landscapes, particularly those that are disconnected from historical waterways via development, I would love to hear about them.

BONUS: HIDDEN HYDROLOGY READINGS

Note: This post was originally posted on Substack on 12/11/24 and added to the Hidden Hydrology website on 04/22/25.

Daylighting Tibbetts Brook

Jason Kingart, case study, city, climate, creeks, cultural, daylighting, design, ecology, equity, history, infrastructure, maps, new york, places, projects, research, streamsLeave a Comment on Daylighting Tibbetts Brook

The recent essay, “Daylighting a Brook in the Bronx” (Pioneer Works, 10.23.24), by Emily Raboteau, focuses on a high-profile stream daylighting project from a resident’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 Brook’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:

“Daylighting will abate combined sewage overflow, extend greenspace, absorb heat, and relieve chronic flooding in our area’s janky, archaic drainage system, in an act of climate mitigation and as a community effort to solve a mess caused by old crimes.”

I’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 ‘cleaning up’ 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:

“I had so many ethical questions without easy answers. It felt uncouth to ask them of a dream thirty years in the making…. 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 brook’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 “perfect” 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 “Rescuing Tibbets Brook” project as part of the Mary Miss-led project, City as Living Laboratory. Works mentioned include Visions of Tibbetts Brook, Tibbetts 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 “the sonic geography of the buried Tibbetts Brook.”

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:

“I appreciate how initiatives like these offer an expansive response to catastrophe, a way to gather, and even a sense of hope. It’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.”

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 “perfect” 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:

“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.”

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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 ‘drainer’ 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, “NYC: Watercourses to Undercity” (Hidden Hydrology, 12.28.17).

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

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

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 ‘spongy’ green infrastructure, hardening critical infrastructure, and methods to “unclog drains and widen pipes.” I’ve written about Eric Sanderson’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, “Let Water Go Where It Wants to Go” (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.

“Water 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 — expressed through tax dollars — to help people move to safer places.”

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 — which was alluded to by Raboteau — 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:

“Though 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.”

To learn more about this concept, I wrote on “Captured Streams” (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.

Lost Rivers for Underground Energy

Jason Kingaquifers, case study, city, climate, energy, infrastructure, london, maps, research, rivers, streams1 Comment on Lost Rivers for Underground Energy

I was combing through the writings on my original Hidden Hydrology blog, with the idea of bringing in some of the ‘best of’ content still relevant today. This 2018 post, “Underground Energy For London” was worth reconsidering, focusing on a report that identified a significant potential latent in hidden hydrological systems, to provide heat and cut carbon emissions through tapping into underground lost rivers. The specifics came from a group called 10:10 Climate Action, who focused on using London’s now-buried rivers as a source of power, asking the question:

“But what if we could use them to power our city once again? Through the magic of heat pumps, London’s lost rivers could provide low cost, low carbon heating and cooling to the buildings above. They could help us solve the big challenge of decarbonising heat. There’s huge potential for London’s lost rivers to provide clean, efficient and reliable heating for the city – tackling climate change and air pollution. And of course the same technology can be used in other underground waterways like sewers in towns and cities across the country.”.

Unfortunately, the report, nor the group 10:10 Climate Action as far as I can tell, is no longer available online from the original source. I tracked down an online version, so you can download a copy here.

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The use of heat pumps is fairly common practice. Extracting heat from these now piped subterranean waterways, and using this heat for buildings and other uses is more novel, offering an potential alternative power option for London and other cities.

The idea was well-covered at the time: “Lost rivers could heat London to cut capital’s emissions” (The Guardian, 07.08.18) “ noted the potential for underground heat to “cut capital’s emissions”, and the articles “Underground river could heat Buckingham Palace” (The Times, 07.16.18) and “Could Buckingham Palace Be Heated By A Lost River?” (The Londonist, 07.11.18) echoed this, focusing on Buckingham Palace as a visible example of the potential for heating buildings. “London’s lost rivers could heat the city, reduce emissions.” (Earth.com, 07.10.18) took a slightly different slant, focusing on helping curb carbon emissions, similar to the article “A new way to tackle climate change? Heat from underground rivers in London could help cut the capital’s emissions, claim campaigners.” (Daily Mail, 07.09.18).

The concept had also already been implemented in some areas, including Borders College in Scotland, tapping into local wastewater, and the State Ministry Building in Stuttgart, Germany, which tapped into flow from the Nesenbach, a buried river adjacent to the site.  A map extracted from the report (image below) shows a number of the potential sites in London, including The Effra, Stamford Brook, The Tyburn, and the Fleet, all of which have potential sites for the use of these technologies.  Specific places include Buckingham Palace (mentioned in a few of the articles above), which would tap the Tyburn, Hammersmith Town Hall which flows above Stamford Brook, and other buildings like schools and site elements like heated swimming pools, which is currently being done in Paris. 

The following video explains the idea in a specific location, showing an example of a London pub that sits atop an ancient subterranean water source, using this heat pump technology for its heating and cooling for beer and wine.

There are questions on the cost-benefit, and each of these systems would require some infrastructure to be viable, however, it’s pretty exciting to consider the potential of these systems to contribute to energy savings and reduction of carbon emissions. The potential for savings of energy is significant. The Times article noted: “A report from the Greater London Authority concluded that water-source heat pumps could meet 4.8 per cent of London’s heat demand, with sewer heat offering another 6.7 per cent.”

The idea of giving back some of their benefits to the city, even while still being buried underground, is also worth exploration.  While the original report is over six years old, I think the idea is still one that seems worthy of revisiting around the globe, identifying projects that could utilize similar techniques, as we search for expanded tools to battle climate change and rising energy costs. I’d be interested to know if any readers know of other cities today using this for district or building scale systems, or projects that have explored this idea of tapping buried rivers in water and sewers for heating and cooling. Let me know if you have any that come to mind.

Note: This post was originally posted on Substack on 11/16/24 and added to the Hidden Hydrology website on 04/22/25.

Urban Surfing

Jason Kingcase study, design, general, places, projects, riversLeave a Comment on Urban Surfing

There are multiple ways of activating urban waterways, including those focusing on ecological, economic, and social aspects. Urban surfing is a unique way to use waterways in the city for recreation and people-watching, expanding on the use of swimming and boating by modifying the flows of existing rivers or creating artificial waves in waterways. Recently, a few examples of these projects came across my screens, and I was blown away.

Eisbachwelle | Munich, Germany

The most well-known of these urban surf spots is the Eisbachwelle, a standing wave created in the Eisbach River in Munich. According to the article “Eisbach: the mother of all river waves.” (Surfer Today), the site has been surfed since the 1970s, and over time the flow has been modified using planks and ropes to make the swell more consistent. The site hosts surfing competitions and as seen below, all season surfing in the urban core.

Eisbach River Wave (Surfer Today)

A video with more information about the Eisbach is featured in the Vans ‘Weird Waves” series.

Rif010 Urban Surf | Rotterdam, Netherlands

A more recent example that is opening soon, featured in the article “How Rotterdam built a wave pool for surfing inside a centuries-old canal.” (Fast Company, 06.04.24) outlines the plans for the Rif010, billed on the site as the “…world firsts surf pool in the middle of a city.”

Render of Rif010 urban surf spot (Rotterdam Style)

The article delves more into the process of how the park was developed, and what was done to integrate the recirculating system into an existing canal. The project aims to be a destination, with different experiences for beginners to learn, versus areas for seasoned surfers. The club also includes a restaurant and bar, rentals, and several other amenities beyond the surf.

The proposed system, set to open soon after a 12-year process to get it built, produces waves every seven seconds through a complicated mechanical system of pumps, designed by consultants at SurfLoch. According to the article, Rif010:

“…uses pneumatic technology to mirror the way waves form in the ocean. At RIF010, this technology is powered by eight engines that are powered by wind energy sourced from the North Sea. The engines do what the wind does in real life, namely “push and pull” the water to create a succession of waves known as a swell.”

In the United States, a little bit of searching on on the topic yields the story of Big Surf in the 1960s. As noted in the article, “Big Surf: the story of America’s first modern wave pool.” (Surfer Today) discusses the design and development of Big Surf, a totally artificial wave park in Tempe Arizona, simulating real wave action miles from the ocean.

Big Surf (Surfer Today)

Our focus here is less on the water park model and more on activating urban rivers and waterways. The article “River Surfing: The 7 Best Destinations in the USA.” (American Surf Magazine, 04.03.24) showcases several other examples worth a look, a few of which are more urban and river-based versions.

River Run Park | Sheridan, Colorado

Located near Denver, along the South Platte River, River Run Park was constructed with three surfing waves, called Chichlets (seen below), Benihanas, and Nikki Sixx, each providing more difficulty.

River Run Park (Endless Waves)

A plan shows the constriction of the river which were originally drop structures in a channelized stream. As noted in the ASLA Colorado award submittal from DHM Design: “The project reconstructed two large, existing drop structures and replaced them with six lower drop structures that include recreational features from wave shapers for surfing and kayaks to water shoots for kids play.”

River Run Park (ASLA Colorado)

Bend Whitewater Park | Bend, Oregon

Closer to (my) home, the Bend Whitewater Park provides multiple experiences through modification of the hydrology of the Deschutes River. There are 3 distinct channels, one focused on habitat, another for slow floating, and a third, a whitewater channel with multiple waves for surfing, kayaking, and paddleboarding.

The three channels of the Bend Whitewater Park (Jeffrey Conklin/Bend Magazine)

This video from The Register-Guard shows the part in action.

The list above is not exhaustive (please send me others you know about), but gives a snapshot of some European and US places that provide unique opportunities to carve some waves without a trip to the beach. While not focused on the ecological benefits these provide special locations for use of urban waterways for surfers and spectators.

For some bonus reading, the article “A brief history of artificial wave pools.” (Surfer Today) outlines the historical evolution of introducing waves into water bodies through artificial means, dating back to the mid-19th century! It’s probably worth a follow-up on this interesting tangent to the potential of waterway transformation.

Note: This post was originally posted on Substack on 06/11/24 and added to the Hidden Hydrology website on 04/23/25.

Reclaiming Waters in Utrecht

Jason Kingcanals, case study, city, cultural, design, history, infrastructure, places, utrechtLeave a Comment on Reclaiming Waters in Utrecht

I spotted this great project this week on LinkedIn and thought it worth sharing. The transformation of urban highways to waterways is an interesting subset of hidden hydrology worth exploring, with some great global examples we will discuss more in the future. This project traces the history of the Catharijnesingel, a canal removed to create an urban highway in Utrecht in the Netherlands, and more recently transformed from hardscape back to its original form as a canal. This provides a great case study on the benefits of public spaces around water, and the ability to restore lost public and ecological benefits through the restoration of waterways.

An overview can be found on the European Prize for Urban Public Space competition site, (Public Space) which recognizes “…all kinds of works to create, recover and improve public spaces in European cities.” The Catharijnesingel project was the winner of the competition in 2022.

For some background, the original Catharijnesingel was a canal that flowed around the defensive walls of the historic city. A park was originally built in the canal zone in the 19th century but was drained and paved over in the late 1960s to 1970s to create space for a major arterial roadway.

Work on the Catharijnesingel before burial (Public Space)

The before picture shows the Catharijnebaan, the roadway built atop the original canal. In 2002, citizens began to discuss the removal of the roadway and restoration of the canal to its original form.

Photo of the Catharijnebaan, the urban highway removed for restoration of the original canal (Public Space)
Image showing the Catharijnesingel after restoration (© 2021 OKRA/Public Space)

The transformation shows the restoration of the canal and revegetation of the banks. The description provides the context of reconnecting with public spaces in urban environments, and the ability to create new, safe, places to access nature and socialize. As noted in the project assessment, on the Public Space website:

“The Catharijnesingel adapts to this new situation by providing pedestrian paths and boat routes and enough space for outdoor recreation. The emphasis on the different microbiotopes of the green areas also makes a positive educational contribution to outdoor activities, where the changing face of nature can be contemplated while walking (or sailing) on the Catharijnesingel.”

The transformation provides access to the waterway for boating, paddleboarding, shady spots, and water access points along the banks, providing much-needed recreation spaces. The project was built in two phases, over 2015 and 2020 with a total restoration area spanning 1.1 kilometers of length.

Photos showing areas of seating adjacent to the restored canal (© 2021 OKRA/Public Space)

There’s also a great video on the Public Space website with some additional historical background and imagery. The project designer, Utrecht-based OKRA Landschapsarchitecten refers to the higher goal of the project as a “…climate-adaptive backbone for the centre of Utrecht,“ and elaborates on the project goals and results:

“In the 20th century Catharijnesingel became Catharijnebaan: an unattractive urban highway dominated by asphalt and concrete. When offered the chance to revert that development, we took the opportunity to push the idea further to its full potential. As the water returned to the historic Canal area, it brought along a new natural park route right into one of the busiest areas in the Netherlands. The result was an urban landscape that was fully connected to the past, the present and the future.”

Aerial View of the restored canal (© 2022 Stijn_Poelstra/Public Space)

These transformations provide a great example of the power to right some of the previous wrongs in urban areas, creating adaptable, climate-friendly spaces. While the canal was never a natural waterway, the project shows that restoring artificial waterways can provide myriad benefits similar to creeks and urban rivers, providing important hydrologic, climate, and public space goals.

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Note: This post was originally posted on Substack on 05/29/24 and added to the Hidden Hydrology website on 04/23/25.

Milan’s “City of Water”

Jason Kingarchaeology, canals, case study, city, cultural, history, infrastructure, maps, milan, placesLeave a Comment on Milan’s “City of Water”

Milan once boasted a robust system of canals, similar to the well-known waterscapes of Venice. Lacking a large river in the urban area, the canals in Milan were developed in the 12th to the 17th centuries to provide water access and connections that were not part of the original city. The area in the southwest quarter of the city is known as the Navigli district, and today “…remains one of the last true connections the Milanese have with water. The Grand Canal (Naviglio Grande) itself dates back to 1177, making it one of the oldest navigable canals in Europe. Today, it’s packed with bars, cafes, restaurants, art galleries and boutiques; in non-lockdown times, it’s a lively meeting spot or a place for a gentle passeggiata stroll by the water.”

Much of the canal system was buried as part of the modernization of the city, but the system still exists, a few areas see daylight, but most are now underground in pipes. A recent paper by Carlien Donkor, Agenee Bavuso Marone, and Allegra Aprea, “Unveiling Milan’s Navigli and Underground Water Heritage through Integrated Urban (Water) Design.” (Blue Papers, 2024, Vol. 3, No. 1) discusses the Navigli through the lenses of climate adaptation, and water resource management, with a goal to “reclaim Milan’s identity as a “city of water” through a deliberate design methodology informed by the city’s history.”

“Snowfall in the Navigli, Milan” January 1852 (Image source: Angelo Inganni / Blue Papers)

The authors provide additional context for the historical canal and lock system, urban water power dynamics, and how these features had served functional purposes in the original historic city, like draining the marshy landscape mitigating flooding. They also discuss how these can restore the ‘water heritage’, and ways these systems can aid in addressing the contemporary urban issues facing Milan. The system map of Milan provides a hint at some of the main components. Some background, from the authors:

“The Navigli were dug as early as 1179 for defensive purposes, as private irrigation channels, and later as lines of trade and business, and became a part of everyday Milanese life (Aprea et al. 2018). In the past, these artificial rivers were the only source of running water for domestic use; for instance there were many old washing houses along the Navigli like the one in Vicolo dei Lavandai (Ministry of Tourism n.d.). They were even used to transport materials to the Duomo (Milan’s main cathedral) during construction (Tyson 2021; Global Site Plans n.d.). The Navigli system reached its peak during the Renaissance, when Leonardo da Vinci worked on the improvement and expansion of the canals (Tramonti 2014).”

The water system of Milan (Stanqiweb/Blue Papers)
Historical image of canals in Milan (Civico Archivio Fotografico/BBC)

The canals were filled early in the 20th century, many turned into roadways as cars and trains replaced boats for transportation. Like many other cities, the authors note: “…the canals were perceived as sources of disease and odor, and as health and hygiene needs of the growing city became alarming the initiative to conceal them were desirable.”

Incoronata Lock is a remnant of the canal system still visible (Joey Tyson/BBC)

The current system that is the result of this transformation has disconnected residents from the water, changing the nature of the city and diminishing the historical role the Navigli. There have been proposals for reopening the canals and daylighting some of the buried waterways, which are ongoing, however, the authors expand the notion to include a broader spectrum of opportunities to tap the historical legacy of the “city of water” as part of a modern water system. As noted: “By looking into the past and present water infrastructure, surface and underground, technological solutions for collecting, absorbing, filtering and purifying rainwater, formed part of this landscape project.”

This system diagram in the article takes some unpacking, but shows a master plan diagram “showing the hydraulic continuity of the project to the Fossa Interna as well as the three Navigli.” This included incorporating green infrastructure solutions (or in the parlance of some European areas “sustainable drainage systems” or SUDS), which have multiple benefits like restoration of biodiversity, reduced urban temperatures, and amenities.

Waterland master plan (Carlien Donkor, Agnese Bavuso Marone and Allegra Aprea, 2018/Blue Papers).

The ability to use “historical analysis” as a way to create frameworks for modern water systems is highly aligned with the goals of this hidden hydrology project and the authors expand the notion beyond the technical to include the importance of culture in the water solutions.

“For older Milanese, water in Milan evokes a deep nostalgia for the disappeared aquatic city symbolized by the countless depictions in art of the Navigli. The Navigli brought water to the people and people to the water. In the same way, Waterland would do the same. While the call to reopen the canals is good, it should be noted that their water management function is for a different scale of city; this should be translated in a contemporary intervention.”

There is more in the article and references, so would appreciate hearing other’s reactions to the paper’s findings, and perhaps if applicable to other regions. Also mentioned earlier, some of the work is underway to daylight canals in Milan. Notably, a project called Riaprire I Navigli (Reopen the Canals) has a wealth of information on specific worth being done. It is worth a follow-up post for more info (and a good chance to work on my Italian), so stay tuned.

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Note: This post was originally posted on Substack on 05/13/24 and added to the Hidden Hydrology website on 04/23/25.

Colorado River Family Album

Jason Kingart, case study, cultural, design, history, landscape, maps, mexicali, places, research, riversLeave a Comment on Colorado River Family Album

The article “A cartography of loss in the Borderlands.” (High Country News, 02.21.24) outlines the work of artists Jessica Sevilla, Rosela del Bosque, and Mayté Miranda includes documenting the “Archivo Familiar del Rio Colorado.” This “Colorado River Family Album”, in their words “…brings together contemporary art, environmental education and historical research to document bodies of water that are disappearing or are already gone.”

Archival map overlay – Colorado River Delta (Archivo Familiar del Rio Colorado/HCN)

The work focuses on the area around Mexicali, tracing the memories of rivers and waterways that have been erased via burial or polluted by contamination. The town included diverse Mexican and Chinese workers, who helped develop the Imperial Valley in California’s irrigation canals and working farm fields. This has evolved into a border town with maquiladoras, which has led to an industrial urban pattern. For the artists, the connection to this place is important. “They named the project the Family Album to signal its focus on personal connections to the landscape… to show that our relationship with the Colorado River and the landscape of Mexicali is that of a relative.”

The work incorporates historical source data and art in creative ways to discover the lost elements of the Colorado River area. A video on their You Tube page visually explores the ideas the project is tackling, with English and Spanish subtitles.

The project’s website also outlines many specific projects, installations, and workshops created by the collective and through their curated works. This was a call for entries along with Planta Libre, as noted in the ‘Announcement.”

“We began by launching a call in collaboration with Planta Libre and through a resource provided by FONCA for the reactivation of scenic spaces, seeking to receive memories and memories about landscapes and bodies of water that no longer exist, as well as speculations about alternate futures, pasts or presents. for the rivers, lagoons, canals, lakes that used to run through the city of Mexicali. The categories of the call were photos, anecdotes and fictions about the bodies of water of the Colorado River. We receive fictitious maps, newspaper images, family archives accompanied by anecdotes, among other materials. The call remains open and the search for family archives and oral histories continues.”

Work of artist Fernando Mendez Corona – Scarcity and abundance (Archivo Familiar Del Rio Colorado)

Sevilla’s website includes more information on the project and some graphics. She also includes a summary statement:

“Located between geopolitical, epistemological and disciplinary borders, we investigate our relationships with water and territory; launching the Colorado River Family Archive as a technology to generate situated knowledge, collectively confabulating about the interwoven temporalities of our relationships with the more-than-human in the Colorado River Delta.”

Conceptual Diagram (Jessica Sevilla)

The cross-border dynamic is an interesting element of the work, mediating the governmental and political boundaries imposed on the natural systems, and highlighting the power dynamics of water in the US and Mexico. These liminal spaces provide interesting opportunities for exploration, and in the context of the contested borderlands, inevitably weave politics with water and the ecosystems, communities, and people who occupy these spaces.

Map of Colorado Delta and Imperial Valley showing Laguna Salada (Archivo Familiar Rio Colorado Instagram)

Additional information and updates on the project are available via their Instagram and Facebook.

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Note: This post was originally posted on Substack on 05/10/24 and added to the Hidden Hydrology website on 04/23/25.

Ghost Streams and Redlining

Jason Kingcase study, city, cultural, detroit, equity, history, infrastructure, lidar, maps, redlining, research, wetlandsLeave a Comment on Ghost Streams and Redlining

The idea of Detroit’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 “What We Can Learn from Ghost Streams.” (Next City, 05.01.24) talked about Bruce Willen’s work on Baltimore’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 “How ghost streams and redlining’s legacy lead to unfairness in flood risk, in Detroit and elsewhere.” (The Conversation, 03.19.24)

The basis of the research is what are known as ‘redlining’ maps. For a little background, the Home Owners’ 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 ‘hazardous’ or ‘high-risk’ 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 “… to determine whether a history of waterway burial and/or redlining influenced the overall flood risk of communities today.” 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:

“Flood risk is very intricately linked to history, and by ignoring history we may be missing some clues that help us move forward.”

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: “If communities want to protect residents from flooding, it’s crucial for them to map and understand their “hidden hydrology.”

Buried But Not Dead

More in-depth exploration of the research is found in the journal article “Buried but not dead: The impact of stream and wetland loss on flood risk in redlined neighborhoods.” (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 Owners’ 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:

“Although 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.”

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

Using data from First Street Foundation’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: “Flood 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.”

Figure from the article, showing flood risks by type of area “associated with inland, coastal zone, ghost streams, and ghost wetlands within redlined neighborhoods.”

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

“[The]…role 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 “hidden hydrology” may play in increasing flood risk.”

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

The Lost Suburbs of Los Angeles

Jason Kingarchaeology, case study, city, creeks, cultural, ecology, habitat, history, infrastructure, landscape, los angeles, maps, research, streams, watershedsLeave a Comment on The Lost Suburbs of Los Angeles

Strong connections exist between hidden hydrology and the larger work of historical ecology, in terms of methodology and the work to piece together complete stories from fragments of disparate sources. Often the traces of historical waterways inform the larger ecological patterns of places to establish baseline conditions, and historic vegetation patterns, and begin to establish markers to document change. The overlay of indigenous occupation is an additional element, however, it is often hard to reconstruct due to a lack of physical documentation. Examples of projects successfully implementing this type of work are valuable case studies.

A recent article, “Tribal leaders and researchers have mapped the ancient ‘lost suburbs’ of Los Angeles” (Los Angeles Times, October 9, 2023) explores a successful process, highlighting work by groups using these techniques to study six village sites in the greater Los Angeles region. These “lost suburbs”, in this case, are the original settlements and villages within the LA Basin, where, as noted in the article, “…culture thrived here for thousands of years amid a landscape of oak and walnut woodlands riven with waterways teeming with steelhead trout and prowled by wolves and grizzly bears.”

Ancient routes and key village locations (LA Times)

Three tribes, the Chumash, Tataviam, and Kizh-Gabrieleño collaborated with diverse interdisciplinary academic researchers to piece together a tapestry of inhabitation, as noted in the LA Times article by one of the project leads, UCLA’s Travis Longcore: “We had to dig deep for evidence of the great society buried under our modern empire of terraced and graded slopes, rivers sheathed in concrete, industrial development, freeways and sprawl.” 

These provide a trail of evidence to follow for appropriate ecological restoration and responses to climate change. Hidden hydrology is one essential key to the understanding of these ancient places. From the LA Times: “One map reveals the locations of streams, wetlands, vernal pools, and tidal flats that were buried or drastically altered to accommodate urban development.”

Comparison of development impacts on waterways (LA Times)

This is a part of the full historical ecology of the region discussed in the following section. Understanding the pre-colonization waterways allows for restoring places informed by an authentic indigenous history. As noted by Matt Vestuto, one of the collaborators from the Barbareno/Ventureno Band of Mission Indians:

“…the mapping project offers hope for a long overdue reappraisal of Native American history… Almost overnight, we were disenfranchised from the landscape — but our people are still here… now, the challenge is to restore the environment, and rebuild our nations.”

The project is part of a larger Los Angeles Landscape History project, with a report published in 2023 outlining the details of this analysis of the Indigenous Landscape of the city. A key component of the analysis is mentioned in the Executive Summary:

“Descriptions of the historical landscape patterns and function have led to a conclusion that this landscape and region cannot be understood without listening to the stories of Indigenous people who managed this land and thrived for thousands of years before the arrival of European settlers.”

A key part of the work is cartographic regressions, which include reconstruction of the topographic history and hydrological patterns using old maps, aerial photography, and other archival sources, like texts, drawings, place names, historical accounts, and archaeological work. The analyses look closely at trade networks, historical flora and fauna distributions, and their impact on habitat, and provide the blueprint for future restoration. As noted in the Executive Summary:

“This project is unique because a commonly shared, detailed map of the historical ecology—the flora, fauna, hydrology, and landforms, that evolved within Southern California’s Mediterranean climate over millennia and supported human populations for 9,000 years, has never been developed.  Individually and cumulatively, the results of this research are vital resources to all regional and local planning efforts involving sustainability, habitat restoration, and preparing for climate change.”

Story Maps

An interactive Story Map is also worth checking out, providing a visual executive summary of the report. Focusing on the section related to Historical Water Features, the team traces stream routes in intervals, including 1896-1903 and 1924-1941, with the ability to compare, via slider, the two time periods as shown below, and highlights the radical change of regional hydrological patterns as the city developed.

Historical Water Features 1896-1903 (LALAH Story Map)
Historical Water Features 1924-1941 (LALAH Story Map)

The citywide mapping of vegetation types is directly related to these original historical waterways, and an interactive map, based on the Military Grid Reference System (MGRS), using a 1km grid, to provide map data in cells of potential natural vegetation (PNV). This is described in the Story Map as the “…vegetation that would develop in a particular ecological zone or environment, assuming the conditions of flora and fauna to be natural, if the action of man on the vegetation mantle stopped and in the absence of substantial alteration in present climatic conditions.”

Map of Hypothesized Potential Natural Vegetation of the Los Angeles Region (LALAH Story Map)

The connections between hidden hydrology, historical ecology, and indigenous occupation are more than just understanding the past. As the researchers point out, the ability to employ this data for solutions to loss of biodiversity, climate change impacts, and other challenges, while celebrating the cultural legacy of place, is key. There’s a wealth of information worth studying this model in more depth, to better understand the Los Angeles Basin ecology and hydrology and to refine and adapt this approach to other regions, specifically centering Indigenous stories as a key component in historical ecology work.

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Note: This post was originally posted on Substack on 05/01/24 and added to the Hidden Hydrology website on 04/23/25.

Ghost Rivers of Baltimore

Jason Kingart, baltimore, case study, city, creeks, cultural, design, explorations, maps, places, streamsLeave a Comment on Ghost Rivers of Baltimore

One of the cooler examples of hidden hydrology art in the past year is “Ghost Rivers”, the brainchild of designer and artist Bruce Willen of studio Public Mechanics.

Ghost Rivers (Ghost Rivers)

Envisioned as a “…public art project & walking tour, rediscovering hidden streams and histories that run beneath our feet.” Willen uses traffic striping and signage to highlight multiple sites around the city, particularly Sumwalt Run, a buried creek that “now flows entirely through underground culverts beneath the Remington and Charles Village neighborhoods.”

The site includes some great background, including the history of the streams and their burial, along with some great illustrations of the path as it winds through

Stream burial (Baltimore DPW Archives, Ronald Parks – Ghost Rivers)
Sumwalt Run pipe (Ghost Rivers)

The installation itself is simple, using durable thermoplastic traffic striping in a wavy pattern that allows the line to engage with people in multiple ways and follow curbs and walks – so it is interrupting the linear flow patterns of walkers, cyclists, and driver throughout the city. This allows the eye and the curiosity to wander along these paths and connect the dots.

Images of the meandering blue path in the public realm (Ghost Rivers)

Self-guided walking tours are available and will expand as more sites are included, along with a Google map to track the route and key points. The signs are also simple, but bright and noticeable for those passersby, allowing for a bit of interactivity as they line up with the views of the meanders, and provide some background information and QR codes to scan for more engagement.

Ghost Rivers Sign (Colossal)

The summary statement explains the idea of connecting us with these hidden creeks.

“Below the streets of Baltimore flow dozens of lost streams. These ghost rivers still cascade from their sources, the many natural springs around the city. As the street grid sprawled outward from the harbor, these verdant waterways were buried in concrete tunnels. They now run deep beneath our rowhomes, channeled into the city’s storm sewers, hidden and mostly forgotten. You can sometimes hear their rushing waters echoing up from storm drains.”

The site also includes awesome resources for more information, history, daylighting resources, and other artistic interventions worthy of a follow-up, including a few I’ve posted about in the past and a few new ones. This is a model that is highly replicable in almost any city, using materials that are simple and evocative in unique ways to highlight those subterranean stories and make us reconsider our relationships with the hidden hydrology.

Closeup of Sumwalt Run marker (Ghost Rivers)

The idea is one of the most cohesive and elegant takes on the idea of revealing creeks using blue lines tracking the historical routing of the waterways. It draws upon precedents, mentioned by applying traffic coating, markers, or paint to mark the route of creeks, most similarly artist Sean Derry’s work in Indianapolis ‘Charting Pogue’s Run” and Henk Hostra’s “The Blue Road” in Drachten, The Netherlands, the proposed “Ghost Arroyos” in San Francisco. Another art-based example from Baltimore is the “Green Alley” street painting, and more loose, ephemeral versions in the St. George Rainway in Vancouver, B.C., in São Paulo, Brazil as part of the Rios a Ruas project, Stacy Levy’s Stream Sketches in New York City.

There are lots of examples of this type of project, and it is interesting to see the different ways a simple blue line can be used to engage in revealing historical layers. So let me know if you have other favorites you’ve seen.

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 04/29/24 and added to the Hidden Hydrology website on 04/23/25.