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Cape Town’s Disappearing Water

Jason Kingaquifers, art, cape town, city, creeks, drinking water, infrastructure, maps, precipitationLeave a Comment on Cape Town’s Disappearing Water

“Day Zero” is the tag line for troubling news from Cape Town, South Africa. The term marks April 21st, which is when they expect the city to run out of drinking water. A story from January 18th, via PRI’s The World, Cape town could be the first major city in the world to run out of water‘ offers some perspective.  Listen below:

There has been water rationing efforts for some time, and the news isn’t new, but the  including.  After ‘Day Zero’, residents will have to get water from city collection points, where they are limited to 25 liters per day.

A dashboard from the City of Cape Town provides information on efforts to combat the .  It also confronts with the harsh reality – as of writing this on 01/30, the date of Day Zero had been moved up to April 16th, five days earlier that originally estimated, along with an announcement that “Level 6b water restrictions are in effect from 1 February, which requires all to drop their daily use to 50 litres pp/day or less.”  

For some context, 50 liters is a little over 13 US gallons, which in terms of daily usage is quite low, for instance a page from Water Science School of the USGS estimated that average daily usage is around 80-100 gallons per person, and that a shower can use from 2-5 gallons per minute.  How long will 13 gallons last, when you also must use that for drinking water, cooking, and other daily necessities.

A post from today via The Map Room, provides some visual to accompany this, linking the NASA Earth Observatory, which includes this animate map, with a description from the site: “The animated image at the top of the page shows how dramatically Theewaterskloof has been depleted between January 2014 and January 2018. The extent of the reservoir is shown with blue; non-water areas have been masked with gray in order to make it easier to distinguish how the reservoir has changed. Theewaterskloof was near full capacity in 2014.”

The rapid depletion is driven by what’s been termed a 1000 year drought, which is also amplified by more development.  The cycle of reservoir levels at the dams show this trend since 2013.

There are new technologies being attempted, such as increasing capacity of dams, drilling to tap new aquifers, and desalination plants, all of which won’t be online in time to avert Day Zero, and come with costs that some are balking about, but could help future issues.  PRI also mentions some strategies employed beyond conservation, such as rainwater harvesting .

An article from March 2017 explored similar topics, via The Conversation “Stormwater harvesting could help South Africa manage its water shortages.” discusses strategies “ to adapt to and mitigate water insecurity threats,” including stormwater harvesting from building roofs, stored using ponds, which “can improve water security and increase resilience to climate change in urban areas. It can also prevent frequent flooding and provide additional benefits to society – such as creating amenities and preserving biodiversity.”

An image of one of these projects above shows the holding capcity and amenity. They seem small compared to the massive Cape Town reservoirs which collectively hold over 400 million cubic meters of water, but studies show that collectively “stormwater harvesting had the potential to reduce the total current residential potable water demand of the catchment by more than 20% if the stored stormwater was used for purposes like irrigation and toilet flushing.”  There are also residual benefits including value from amenity value, property values, and flood reduction.

COULD LOST RIVERS BE THE ANSWER?

Could the buried springs and creeks provide a supplemental source for drinking water to combat the Day Zero?  As far back as 2013 is an article from Cape Times entitled ‘Cape’s spring water wasted‘, which discusses the work of Caron von Zeil, and Reclaim Camissa “a project that uncovered and documented the vast amount of fresh water that flows underneath Cape Town.”  Identifying the springs and streams that have been paved over potentially provides opportunity to capture drinking water to supplement shortages.

From the article: “Von Zeil’s archive research showed that historically there were 36 springs in the City Bowl. She has uncovered 25 springs and four underground rivers. The City of Cape Town has only 13 springs on their records. Parliament is sitting on two springs and a huge underground reservoir.”

The above photo via their Facebook page is captioned: “This is NOT a riool (sewer) – 8.8million litres of Water flows through here to the ocean on a daily basis…lost to nature and humanity. This is HYDROCIDE.” which gives a taste of the tone.  This strong advocacy they attempt to raise awareness, coupled with  pilot projects, Reclaim Camissa such as a proposal called Field of Springs, which “was to be based on vacant council land in Oranjezicht where several springs were located. It would harness the spring water and be an outdoor water museum with natural ponds where people could see the water being cleansed. It would have an outdoor laboratory, education centre, bird hide and a bottling system where offices that used large glass water coolers could tap into the spring water.”

Von Zeil gave a TEDxCape Town talk in 2011 discussing Reclaim Camissa.  Via the intro it explains that “CAMISSA, meaning ‘the place of sweet waters’ is the ancient Khoi name for Cape Town. Embedded, lost and obscured within the city’s fabric this vital ecological and cultural link still exists….  The vision is one of a genuinely progressive dual water management strategy that offers opportunities for new models to transform the future wellbeing of the city into an equal society for all people; and allows for public integration and education through the recreational use of the system.”

Check out the full talk here:


On a related note, those locals can tour some of these sites via a web app “Cape Town’s Secret Tunnels and Lost Rivers“.  A summary: “Join Matt Weisse on a leisurely walk through the city, following in the path of the old underground rivers and tunnels to the Castle of Good Hope. Parts of the underground Canals and Rivers date back to 1652. They used to supply the passing ships with fresh water. Later these rivers became pleasant walkways shaded by Oaks with bridges going over them. As the years passed and the city expanded they were eventually covered up and forgotten.”

The app provides a map with audio clips of key sites, can’t vouch for the 5.99 price tag, but seems like a cool idea.

HEADER: Image of the ‘Cape Town’s main water supply from the Theewaterskloof dam outside Grabouw, Cape Town, South Africa’ (From the AP, retrieved from Spokesman.com)

 

London: Art, History, Exploration

Jason Kingaquifers, archaeology, art, city, creeks, cultural, explorations, film, general, history, infrastructure, landscape, literature, london, maps, photography, places, precedents, rivers, streamsLeave a Comment on London: Art, History, Exploration

As January is quick turning into London month, we’re wrapped up on the summaries of available books on the subject, including works by Barton, Myers, Bolton, Talling, and Fathers, running a gamut of approaches to walking, studying, and mapping Lost Rivers.  I’d also be remiss if I failed to call back a 2016 post on another take on the subject, Iain Sinclair’s 2013 book ‘Swimming to Heaven: London’s Lost Rivers‘ which rounds out my collection on the subject.  The amazing amount of hidden hydrology literature provides a solid foundation, however, it is merely the tip of a massive iceberg visible layer of a vast and sprawling underground complex of content, and a starting point for discussing many of the other resources and discussion around the subject, including art, history, exploration, and maps.

A quick search of London and Lost Rivers or something along those lines yields plenty of material, including additional resource from the sources as diverse as London Geezer, which contains an extensive amount of information, to city specific hidden hydrology projects such as the Lost Rivers Project in Camden. A lot of ink (at least digitally) has been spent on this topic, with articles from BT like “8 of London’s lost rivers you probably didn’t know about” to BBC “The lost rivers that lie beneath London?“, the Telegraph (authored by none other than Tom Bolton, “The fascinating history of London’s lost rivers“, and perhaps the most prolific, the Londonist which covers this topic often, with titles like “The Secrets of London’s Lost Rivers” and info on specific rivers like “Counter’s Creek: In Search of London’s Unknown River” (authored by David Fathers) to a multi-part “Lost Rivers from Above: The Tyburn“.

Without going into extravagant detail and barrage you with too many links (there are over 100 I have at this point), it’s safe to say that London is by far the city with the most coverage, and it continues to emerge (such as this interactive virtual reality tour on the Guardian of London Sewers), showing that it’s a topic that continues to intrigue people.  For now, we’ll focus on some projects that work directly in the realm of these lost rivers, interpreting them directly through exploration and indirectly through art.

ART/EXPLORATIONS

Much of the interpretive work around hidden hydrology comes from art, in it’s various forms, and much of the art includes exploration, so I’m combining these two ideas in one here. We’ve previously featured artist Cristina Iglesias and her new installation Forgotten Streams in London as more of a site specific example, interpreting the Walbrook in water features outside of the new Bloomberg London HQ.

A spatial approach comes from Sandra Crisp, and her video project from 2010-2012 “Mapping London’s Subterranean Rivers”.  This work was “originally made as a site-specific installation for a group exhibition 2010 held in the semi derelict basement under Shoreditch Town Hall, London”  A soundtrack was added later and you can check out the full video at the link above.

A short blurb (with my one small edit) from the site: “The film allows the viewer to fly through a 3D map of London, revealing the sites of ancient and subterranean rivers based on research using old maps and books such as Nigel Nicholas Barton’s ‘The Lost rivers of London’. Evoking existing and long disappeared waterways that bubble unseen beneath our feet. Including; The Fleet, Tyburn, Westbourne, Quaggy, Counters Creek, Neckinger and more…..”

A detail shows the intricacy of the layering, in this case highlighting the River Wandle – but the stills don’t do it justice – check out the video for full effect.

Crisp also breaks down the research on the piece, where she shows a hybrid version of Barton’s map that was the basis for the piece, along with some of the ‘making-of’ info that’s pretty interesting.

Amy Sharrocks, a London based artist, sculptor and film-maker, created “London is A River City” from 2009.  As she mentions in her bio “For the last four years I have been making work about Londoners and our relationship to water, inviting people to swim across the city with me, floating boats to drift on swimming pools, lake and rivers, tying people together to trace lost rivers and re-create a memory of water.” 

The project included walks of lost rivers, which involved using dowsing as a methodology for walks of the Westbourne, Tyburn, Effra, Fleet, Walbrook, and Neckinger rivers.  Each of these are beautifully documented (with PDFs as well for download), and worth exploring in more detail.  Per her statement “Why I’m Doing it?“, she mentions:

“Tracing these rivers has been a process of layering: new stories over old, our footsteps over others, roads and railways over rivers. Uncovering a past of London I knew nothing about. Connecting to things submerged beneath our streets has uncovered a currency of the city, and enabled a kind of palm reading of London. 

The idea of walking is vital to this endeavor, coupled with the dowsing gives it a pyschogeographic slant. From her site:  “These rivers lost their claim to space in this city, long ago paved over, with their inconvenient tides and smells, to make way for faster roads and railways. These river walks have championed a human speed, that stumbles, stops to look at things, slows down when it is tired. There is a connection to the speed of water, a meandering dérive to battle the rising pace of modern life. We took the measure of London by our own strides, pacing out the city at our own speed.”   Flash-enabled website headaches aside, it’s a good project worth some time to dive in.  Read some coverage from the Independent on the Walbrook walk.  You can see more about some other work as well at SWIM .

Another project, this time with a poetic bent, comes from via ADRIFT, a project by poet Tom Chivers envisioned as a “…personal interrogation of climate through poetry.”, where he “sets out to explore climate as culture, mapping out the territory of climate science within urban space.”  The site has the full list of writings, and a nice archive of some related materials are also on the site.  It’s a project of Cape Farewell, which has a great mission of “bringing creatives, scientists and informers together to stimulate a cultural narrative that will engage and inspire a sustainable and vibrant future society”, namely climate change.  An image from the ADRIFT site as part of a photoset “Walking the Neckinger: Waterloo to Bermondsey”

A graphic design work Hidden Rivers of London by Geertje Debets takes a different, more visual approach, as “A research on the letterpress technique, while developing the concept and design for the visualisation of the underground rivers of London.  London’s terrifying under half… Sometimes you can catch a glimpse of this underground life, but when you look better, you find the underground world everywhere, especially the underground rivers. The names of the underground rivers are used in street names, places, houses, companies, schools and orchestras. The locations of these places show you how the river floats.”

The work of Stephen Walter got a bunch of press a few years back, with this map of London that “…traces the lesser known streams, sewers, springs and culverts of the capital in intense, hand-drawn detail.”   Some enlargements of these maps, via the Guardian:

Another of Walter’s work that is worth seeing is the 2012  “London Subterranea“, which “…aims to shine a light on this clandestine infrastructure and it presents perhaps the first comprehensive map, open to the public, which places so many of its features alongside each other. It geographically tracks the routes of London’s Lost Rivers, its main sewers, the tube network and it’s ‘ghost’ stations including the Crossrail project. It also pinpoints archeological finds, ruins, known plague pits, secret governmental tunnels, the Mail Rail and the Water Ring Main tunnels. Epithets to the ‘underworld’ of crime, and the scenes of notable killings such as the acid-bath murders get a look in. So too does the site of the infamous Tyburn Tree and its many buried corpses that still lie in its wake undiscovered.”  

On the topic of the subterranean, photography as well plays a part, with many of the London area rivers featured in a National Geographic photo-essay, “11 Rivers Forced Underground“.  A book on the subject I’d like to pick up, Subterranean London: Cracking the Capitol (2014), is described via a blurb from Amazon:  “Bradley L. Garrett has worked with explorers of subterranean London to collect an astonishing array of images documenting forbidden infiltrations into the secret bowels of the city. This book takes readers through progressively deeper levels of historical London architecture below the streets. Beautifully designed to allow for detailed viewing and featuring bespoke map illustrations by artist Stephen Walter, this unique book takes readers to locations few dare to go, and even fewer succeed in accessing.”

The publication had some acclaim, with one of the images winning an architectural photography award, along with some controversy as noted in the CityLab article “The Photography Book London Officials Never Wanted You to See” which outlines some of the sticky issues of urban exploration, access, liability, and such. Content addresses more than just hidden waters, but does include some amazing photographs as seen below.

This resource on London sewers from 2011 that looks to no longer be actively maintained, is ‘Sub-Urban: Main Drainage of the Metropolis‘ which looks at the drainage via sewer exploration and photography: “Alongside more traditional study and research practices, such as access to archival materials and the use of other historic and literary resources, we apportion equal importance to the hands on scrutiny of our subject matter. Taking time to explore, investigate and photograph London’s sewers affords us a greater understanding of the often complex architecture and gives practical insight and knowledge that cannot be gained from any amount of time spent thumbing through books and documents.”  There’s a number of links on the site to other endeavors, as well as some great imagery, both current of their explorations, and some historical work, along with the timeless phrasing of the section “Close Encounters of the Turd Kind“.

And when you’re done exploring, you can always grab a pint at Lost Rivers Brewing Company and drink the range of available beers inspired by the rivers themselves, and perhaps peruse Ben Aaronovitch’s 2011 book “Rivers of London“, where he created a story around various water deities and river spirits on the Thames and areas of London.

HISTORY

The concept of hidden hydrology is intertwined with history, so threads weave through all of these art installations and explorations.  The history of the development of London is fascinating and overwhelming, but there are some great resources like British History Online, which has resources on the topic like the six volume “Old and New London” written in the late 19th century, to sites like Connected Histories, which provide timeline based search tools, or links from the London Historians’ Blog.

On the topic of Lost Rivers, the history of the Big Stink is pretty key historical moment, which was a vital impetus behind what became the modern sewage system and led to the demise of many urban rivers.  The idea of this also led to “a piece of Victorian science fiction considered to be the first modern tale of urban apocalypse”, William Delisle Hay’s 1880 novel “The Doom of the Great City”, which is covered in depth via this article in the Public Domain Review.

You can also access primary sources, such as  following along with Sir Richard Phillips as he explored the edges of London in 1817, in “A Morning’s Walk from London to Kew“.

Some visual history comes via ArchPaper “What a difference 400 years makes: Modern and medieval London contrasted in hand-drawn cityscapes” which takes historic drawing viewpoints and redraws them showing the current urban configuration.

A fascinating thread that came from some of the books was the legacy of Spas, Springs, and Wells that have been a long part of the history of London.  There are some good sites to engage with this history, such as London’s Holy Wells, or the resource Holy and Healing Wells, highlighting around around the globe, including London.  There’s some great documentation such as the book mentioned by Barton, Foord’s “Springs, streams and spas of London: history and associations” from 1910, and one mentioned to me by David Fathers, Sunderland’s “Old London’s spas, baths, and wells” from 1915, both great resources for hidden hydrology.  An illustration from Foord, showing a 1733 engraving of one of these places, Tunbridge Wells:

The history of the Thames River Postman is a bit more random but worth a read, outlining H.L. Evans who delivered mail along the Thames. “The Thames Postmen played an important role connecting people who lived on the river with the rest of the world. They also became something of a local celebrity being a constant in the fast changing landscape of the river. Considering that the job was not without its dangers, it was remarkable that the Evans dynasty managed to continue for over a century.”

A visual resource COLLAGE, is an image database of over 250,000 images from The London Metropolitan Archives and the Guildhall Art Gallery, and also includes a picture map so you can locate them spatially in London.  A quick perusal found me in the Serpentine in Hyde Park, which showed this 1795 “View of Cheesecake House, Hyde Park.”

The concept of the larger regional picture is the website Vision of Britain over time, which is full of great information, and specific to the landscape is the book ‘Hidden Histories: A Spotter’s Guide to the British Landscape‘ by Mary-Ann Ochota which helps decipher the immensity of history through interpreting landforms and other traces.  From a review in Geographical:

“There is so much history to the British landscape. What with its stone circles, hill forts, mines and umpteenth century cottages, the land is marked with centuries of use. This can make it hard to read, like a blackboard written on hundreds of times and never erased”

As you can see, plenty of great work has happened and is still happening in London.  This is not an attempt to be comprehensive, and there’s tons more out there on specific rivers and locations, so consider this a teaser of sorts and google away for more.  I’m trying to find a simple way to share the mass of my resources and links online for further reading and reference, so stay tuned there, and future posts will likely expand on this rich history around hidden hydrology.  As a last reference to London, the last post in the series for now, following the lead of New York City, will be on maps.

 

HEADER:  Hand drawn map of the Rivers of London by Stephen Walter.

London: Walking on Water with Myers

Jason Kingaquifers, city, creeks, geology, history, infrastructure, lakes, london, maps, places, rivers, streamsLeave a Comment on London: Walking on Water with Myers

The final installment of books looking at London hidden hydrology is Walking on Water: London’s Hidden Rivers Revealed, by Stephen Myers.  As part of the parade of books on the topic published in 2011, this takes a very different approach than the tour/photo guides of Talling and Bolton, reflecting Myers’ background as an engineer.  If you’ve checked out the previous post on the Barton book, you’ll recognize some of this similar analysis, as the 2016 3rd Edition of ‘The Lost Rivers of London’ includes Myers as a co-author, and seems a hybrid of this book and Barton’s earlier versions.

On that note, Myers approaches the project from that engineering perspective, and its loaded with info.  A blurb from Amazon:  “London’s hidden – or lost – rivers are a source of fascination. This book concentrates on seven North London rivers – the Fleet, the Walbrook, the Tyburn, the Westbourne, Counter’s Creek, Stamford Brook and the Black Ditch. The author, a professional water engineer, describes their sources and traces their individual histories, setting out their influence on the development of London and their use and abuse by society, eventually leading to their disappearance. The original watercourses of each of the seven rivers are shown on London street maps to a detail never previously attempted. Research to enable this included extensive on-site analysis of their river catchment topographies and desk-top studies of numerous old maps and literary references. Walking on Water ends on an optimistic note. Drawing on his professional experience, the author proposes a practical, affordable and exciting approach to recreating riverside parks and walks in the London boroughs through which the hidden rivers passed, which uses their source waters to refresh the lakes of the Royal Parks.”

Myers breaks down the history of hidden rivers, discusses a good amount on geology and the form of the rivers, and discusses their ‘uses and abuses’, all info covered in other places, but again with a unique focus here.  The second half of the book includes specific rivers, an overall map shows some of the North Bank Rivers (click to enlarge) covered, including all the usual suspects from other books.

Also of interest is a comparative profile, showing the central London Rivers.  The relationship of the rivers in terms of altitude from headwaters to outfall is a complement to plan relationships, and particularly in the context of London where all the rivers flow into the same source, the Thames, it allow for some good comparison.

The development of the City of London is of great interest, named the chapter ‘A City Grows, Its Rivers Beggared’ and how this rapid urbanization impacted the rivers both in demand for fresh water and degradation due to pollution.  The diagram below (which would have aided with some color and texture) shows the expansion of the city, notably the sprawling growth between 1800 and 1900 (marked by the gray inner zone and outer black line).

And while the chapter on ‘Mapping London’s Hidden Rivers’ is helpful in outlining the methodology, the results that come from this work are less than stellar.  All the diagrams and maps here are black and white, using a base map derived from the Geographers A-Z Map Co (similar to Barton & Myers) which again offers legibility and usability issues that leave a lot to be desired.  While the maps in the 2016 book were in color, they seemed overly detailed and took away from the routes of the rivers. In this case, black and white flattens it all out and their small size makes the cramped and difficult to use.  A good hybrid would be a black and white base with the paths drawn in color, perhaps?

As Myers makes a point multiple times, “it was a considerable surprise to learn that there were no large-scale maps, readily accessible to the general public, which showed their routes through the metropolis.” (14)  Perhaps Barton’s original 1962 book insert doesn’t totally qualify as ‘accessible’, but it does, and much more successfully, provide a large scale map of the routes that Myers was missing. He does mention obviously using Barton, and also references a book I had not heard about previously, London Under London by a very appropriately named duo for the task, Trench & Hillman.  Another reference was to a future volume, “Walking on Water – the Hidden Water Walks” to follow this one, but I’ve not found any mention that that project came to fruition.  So perhaps that was going to be the vehicle for better, user friendly maps, that never materialized.

For each river chapter, he does include the sections of the routes, again in very small size, which I think are very helpful for visualizing the routes of streams.

The final chapter does offer a strategy for a project entitled the Hamstead Water Conduit, where he speculates on a proposal that could “recreate short, clean stretches of the Central London rivers – more particularly the Fleet, the Tyburn, the Westbourne, and possibly, the Walbrook, the City of London’s own river.” (200).  He goes on to mention that “the source waters for the Fleet, the Tyburn and the Westbourne rivers are the springs and surface water which drain naturally from Hampstead Health.  These are the only source water of the hidden rivers that have been protected from pollution and which remain eminently accessible today.” (201)

A diagram shows a proposed route, which connects existing daylit portions with new or reconfigured surface channels in places, fed by the springs mentioned above.  While not a continuous river, the result is a linear water course that works with the boundaries of the existing city fabric while taking advantage of opportunities to create surface waters.  A “…‘feel-good’ project” but one with environmental benefits, flood mitigation, recreation, tourism, and infrastructure reduction. As noted by Myers, the social benefits as well, allowing us to “lift spirits in depressing times, but also contribute a small stimulus towards better economic times.” (208)

A more technical diagram shows some of the interconnections between the old and new systems, as well as the make-up water using existing groundwater stores (a metaphorical routing) and creating a water balance that kept water uses constant while using excess flows to ‘restore’ river segments.

 

The strength of this book, as indicated in the above analysis, is a solid, technical background in both the formation of rivers, the geological and hydrological framework in which these waterways emerged, the development implications that drove them underground, and some realistic considerations on why it would be difficult to daylight them, as they have been so fully consumed into the existing sewer systems. But also, some defensible and plausible daylighting strategies that take these multitude of factors into play.

The glossary ‘Watery Definitions’ on page 20 is a good touch, and discussion of what is a creek, stream, river, etc. is one that few tend to delve into in any detail.  As he mentions, due to size and typology, “it might seem more approrpriate to make reference to London’s ‘Hidden Streams’ rather than to London’s hidden rivers, as the flows in them could not really be described as ‘copious’ and their water surface widths generally lay in the narrow band of between 2 and 6 metres.  However, these watercourses have been referred to historically and collectively as ‘rivers’, and so this book will perpetuate that possibly inaccurate usage.” (22)

The Disclaimer at the beginning was interesting as well, as it seemed appropriate for anyone with a background in design and engineering to include the cover-your-ass language about accuracy, liability and not using the information for specific purposes.  This shows up also in the later Barton & Myers version of Lost Rivers, but does bring up a point about representation and what it could mean.  The accuracy of old maps .  He also warns about sewer exploration, I guess as well a necessary caveat for disseminating this type of information.

Each book I’ve covered offers something unique to the conversation, and this provides a great resource for those interested in London, but also a wider context of the emergence of urban creeks and rivers which seem applicable to all places.  A level of technical rigor also makes this a valuable companion to other resources that focus on places, history, landmarks and culture.

 

 

Montreal’s Underground Cavern

Jason Kingaquifers, city, geology, history, montrealLeave a Comment on Montreal’s Underground Cavern

While the focus of investigations in Hidden Hydrology are often around the lost, buried and disappeared, the true nature of the hidden comes up in some interesting ways.  A recent article via the CBC discusses a new find “‘This is a major discovery’: Explorers find massive ice-age cavern beneath Montreal” and discusses a hidden “Cathedral-like chamber, formed more than 15,000 years ago, [which also] features underground lake”.

The spot was found by cavers who busted through a wall in the popular the Saint-Leonard Cavern,  The cavers, “Le Blanc and Caron said they were able to pinpoint the location of the passageway using a dowsing rod, similar to the wooden divination tools sometimes used to find groundwater.  The two men, who first got into caving as a hobby, said they’ve been searching for an unknown branch of the Saint-Léonard cavern for years.”

A video of the exploration:

While groundwater and aquifers are well known to exist in cities, the relationship of surface and subsurface geology and hydrology makes for some interesting interactions with hidden hydrological regimes – in this case subterranean interface with the aquifer. Perhaps few examples as extreme as this in modern cities, but interesting to see something hidden for years emerging after so long.

Source of the header image:  Massive Underground Cavern Formed During Ice Age Discovered By Amateur Explorers (IBT)