I posted some amazing images last year of changing course of the Willamette River captured with LIDAR, evoking wisps of smoke leaving a palimpsest of tracings across the landscape.  A recent article from National Geographic’s site ‘All Over the Map‘ entitled ‘See the Strange, Beautiful Landscapes Revealed by Lasers‘ reminded me of the beauty of this digital technique, showcasing some additional regional imagery and including hydrology and geology, this time focused in the State of Washington.  A few of the images included:

The Quinault River on Washington’s Olympic Peninsula has meandered extensively in the past, leaving behind dry, abandoned stream channels filled with river sediment that are revealed by LIDAR.
Channels in northwestern Washington formed when melting glaciers caused major floods. The channels are highlighted near the center of this LIDAR image.

The images are beautiful and intriguing, owing to the ability of LIDAR to penetrate vegetation layers to reach surface levels often unseen with traditional methods.  The beautiful imagery in the article is from the Washington Geological Survey site ‘The Bare Earth’ which is a descriptive resource on “How lidar in Washington State exposes geology and natural hazards”.

While useful for many types of analysis, this is particularly important to identification of landscape hazards, which had devastating impacts in 2014 in Oso, a town north of Seattle, and you can see some of the images highlighting landslide activity in the region.

A landslide covered with vegetation near Deming, Washington is revealed with LIDAR.
Old landslide scars on the Cedar River near Seattle are normally obscured by forest, but are plainly visible in this LIDAR image.

The most intriguing image to me was the Mima Mound Natural Area Preserve, which I hadn’t known about before reading this, which look much like a magnification of dermis instead of earth.

The mysterious Mima Mounds near Olympia, Washington are beautifully exposed in this LIDAR image. The origin of these mounds, which are 6 feet tall and 30 feet wide on average, is unclear and has been attributed to gophers, insects, wind, earthquakes, and the shrinking and swelling of clays.

The landscape itself is subtly rolling like an earthworks art project, and the reasons for their form is up for debate, as seen in the caption above.  The landscape itself is subtle and beautiful, definitely motivated to take a trip down to Olympia.

The pages on the great context on how LIDAR works with a story map of some visuals along with descriptive illustrations.  Per the WGS site,

“Lidar (light detection and ranging) is a technology that uses light pulses to collect three-dimensional information. Lidar data is often collected from an airplane using a laser system pointed at the ground. The system measures the amount of time it takes for the laser light pulses to reach the ground and return. Billions of these rapidly-collected measurements (points) can create extremely detailed three-dimensional models of the Earth’s surface. See the diagram below to better understand how airborne lidar is collected.”

A breakdown of the different maps that be extracted from the process.

The beauty of LIDAR is the ability to give an alternative view that is impossible to capture in other ways, particularly in deeply vegetated sites, with lots of coniferous vegetation. Again, from The Bare Earth site: “In geology, lidar bare-earth models allow closer study of geomorphology, which is the study of the origin of the topography of the earth. Landslides, faults, floods, glaciers, and erosion leave their mark on the landscape, and while these marks can be hidden by dense vegetation, they can’t hide from lidar.”

Harkening back to the previous posts of the geology of Seattle, the glacial retreat was a major factor in the Seattle-area geology and current hydrology.  The image below shows an aerial image, which reveals little of this feature, but the Lidar image shows the directional scarring and drumlin deposition around Hood Canal in sharp relief.

LIDAR shows the landscape around Hood Canal, a fjord in the Puget Sound, which is filled with elongated, rounded hills known as drumlins that were left behind by glaciers.

A video as well elaborates on the technique:

Check out more of Betsy Mason and Greg Miller at All Over the Map and follow them on Twitter @mapdragons

Header image, like many of the other images in the post, is from Washington Geological Survey, via National Geographic,.  The header shows “The floodplain and dry, former channels of the Chehalis River in western Washington State are revealed by this LIDAR-based elevation map.”

Quick post to show the installation by artist Cristina Iglesias, ‘Forgotten Streams’ which is located at Bloomberg’s new European Headquarters in London.  The revelatory landscape is woven through three different plaza spaces, evoking the Lost Rivers of London, namely the Walbrook.

 

Via ArtNet News:

London’s “lost” river Walbrook, which the Victorians built over, appears to have been uncovered this week. The Spanish artist Cristina Iglesias’s Forgotten Streams (2017) now flows gently through the heart of the capital’s financial district, appearing in three places in the pavement outside financial media giant Bloomberg’s new £1 billion ($1.3 billion) headquarters. It is her first public work in London.

While obviously a metaphorical interpretation, the proximity to the actual route (not exact but close) to the Walbrook activates the historical ecology of place.  And I was surprised, actually shocked as I was looking at the original images trying figure out the material used, that it is cast in bronze, developing layers of matted shoreline along with differing water flows and pools.  As abstracted ecology, the integration of this type of artwork into a high-visibility project is great, and while providing minimal ecological value, the historical value is a positive.

Photograph: Guy Bell/Rex/Shutterstock

I think they are pretty beautiful, but it was funny to read the review from the Guardian on the Norman Foster designed building, and a specific reference to this work:  “In a civic-minded gesture, there are three new public spaces at the corners of the site, adorned with water features by Spanish artist Cristina Iglesias, although her green-patinated bronze layers of matted foliage resemble fetid swamps – perhaps a sly comment on the financial services industry.” 

The theme is not a new one for Iglesias, who has tackled similar water-centric themes in previous work (amidst one of the most confounding web interfaces I’ve encountered in some time) and uses the cast bronze as a medium for waterways in other projects in her native Spain, as well as Belgium. More to come on her work as I dive in a bit, but a cool project to encounter.  An image of Iglesias, working with a similar material in the swamp, if you will via CNN:

Credit: Courtesy Lopez de Zuribia

Thanks much to David Fathers for the tip on this one via Twitter.

What’s in a name?  Why does language matter?  I asked this question previously in the post “Language as the Thread“, and it continually emerges and weaves through the study of hidden hydrology.  The names of streams and places, which are shaped by geography and culture, enliven our discovery of the old and the new.  I admit to a love of language, but had not specifically focused on toponyms to the degree I have until reading and following the fantastic Robert Macfarlane, who challenges us to expand these connections by “…collecting unusual words for landscapes and natural phenomena” and celebrating them.  He calls the accumulation the word hoard. and can be best accessed in his 2016 book Landmarks.

For water, like other phenomena, there are many encyclopedias for terms and usage both regional and global to encompass the range of toponymic variations.  And people also like making maps of these as well. The map that sparked this post I saw on Twiiter that was published in 2011 by Derek Watkins –  “Mapping Generic Terms for Streams in the Contiguous United States” which “…illustrates the range of cultural and environmental factors that affect how we label and interact with the world.”   [click to expand and zoom on the map below]

Even though I moved around a bit as a kid, i’m a straight stream or creek person, with an occasional Brook or Fork.  The graphics break down multiple regional variants:

“Lime green bayous follow historical French settlement patterns along the Gulf Coast and up Louisiana streams. The distribution of the Dutch-derived term kill (dark blue) in New York echoes the colonial settlement of “New Netherland” (as well as furnishing half of a specific toponym to the Catskill Mountains). Similarly, the spanish-derived terms rio, arroyo, and cañada (orange hues) trace the early advances of conquistadors into present-day northern New Mexico, an area that still retains some unique cultural traits. Washes in the southwest reflect the intermittent rainfall of the region, while streams named swamps (desaturated green) along the Atlantic seaboard highlight where the coastal plain meets the Appalachian Piedmont at the fall line.”

The focus on non-traditional toponyms for streams is great, although myself, like many others, mentioned “Where are Creeks, or Streams, or …” due to the absence of these being visible on the map.  A bit of digging shows that and he mentions that “This map taps into the place names contained in the USGS National Hydrography Dataset to show how the generic names of streams vary across the lower 48. Creeks and rivers are symbolized in gray due to their ubiquity (although the etymology behind the American use of creek is interesting), while bright colors symbolize other popular toponyms.”  Perhaps its just gray on black, but I think showing in one more visible color (a neutral light blue) and keying these would help paint a picture of all streams and then highlight the stranger ones. Minor graphic critique aside, it’s a cool exploration.

Watkins also references a British version, by James Cheshire on his site Spatial,ly where he created a map Naming Rivers and Places and maps brook, aton, water, river, and canal.

He adds that he:  extracted the major rivers and streams in Great Britain from the Ordnance Survey’s Strategi dataset and coloured them according to whether they are a “river”, “canal” (not sure if this really counts in terms of naming), “water”, “afon” (Welsh for river) and “brook”. You can see that a clear geography exists. I was not surprised by all the “afons” being in Wales but I was surprised to see so many “waters” in Scotland.”

There are many variations I’m sure just from perusing some I wonder about the term Beck, which comes up in a lot of literature in the UK and the studies of some of the lost rivers I’ve read.  According to the quick etymology it is used in Northern England, derived from “Old Norse bekkr, related to Dutch beek and German Bach . Used as the common term for a brook in the northern areas of England, beck often refers, in literature, to a brook with a stony bed or following a rugged course, typical of such areas.”

There’s another link to some simple toponymic maps on by Paul Fly in a set GNIS maps via flickr as well – where these are mapped with less at once so you see the comparative differences, along with some other iterations like Lake/Pond, and Branch/Run/Brook and a plethora of

Some additional links of interest from Watkins post include the book Names on the Land: A Historical Account of Place-Naming in the United States by George R. Stewart which also has a great essay on Slate here.  Additionally he mentions The Cultural Geography of the United States by Wilbur Zelinksky and the writings of Robert Cooper West.

More on toponyms and the application here in the Pacific Northwest in relation to hidden hydrology, and a wealth of additional discussions more generally on language, culture, and water to come.

Another city doing some great work around Hidden Hydrology is Toronto. Featured in the Lost Rivers documentary, the city boasts as range of resources and groups worth some exploration.  A plethora of media fuels the fascination, with numerical and witty titles, including “5 lost rivers that run under Toronto“(blogTO), “5 subtle signs of lost rivers in Toronto” (Spacing Toronto), “Toronto’s ‘lost rivers’ reflect how we’ve reshaped nature“, and “Toronto’s Hidden Rivers” (Toronto Star), “Last seen heading for the lake” (The Globe & Mail),  In particular the author Shawn Micallef a colunmist from the Toronto Star that has looked at disappeared creeks, and lost creeks.  The more general discuss “and “What the Toronto Waterfront used to look like” and connect to the online archive of Toronto Historic Maps and other resources.  The following explores some of this in more depth.

Hidden Hydrology Resources & Groups

Lost River Walks is a long-standing resource in Toronto, “The objective of Lost River Walks is to encourage understanding of the city as a part of nature rather than apart from it, and to appreciate and cherish our heritage. Lost River Walks aims to create an appreciation of the city’s intimate connection to its water systems by tracing the courses of forgotten streams, by learning about our natural and built heritage and by sharing this information with others.”  They include a number of Stream Pages, accessible through the Site Map, which provides history of individual streams, in this case, The Market Streams, which highlights a series of streams and provides some overlay mapping of the current sewer network.

Location of Lost Rivers

 

Location of current sewer system

The engagement is a key part of the group, as the name implies, through a series of guided walks, which highlight lost rivers and creeks  in the context of the urban fabric, as well as focusing on topics like water quality. There are also self-guided tours ‘Thirsty City Walks‘, provides opportunities to follow the former and current routes of waterways. A map below shows the route of the walk with key points and audio commentary as one follows the route.

A great bonus article I found on the Geohistory-Géohistoire Canada Project, authored by John Wilson entitled “The Lost Rivers Project: The Case of Holly Brook“.  This post outlines some of the process, in particular the need for ground truthing, as he mentions, “I have spent many hours travelling the city’s streets and laneways looking for signs of lost rivers and ravines. My street-level observation of Holly Brook’s course was simple – whatever the City Engineers may have drawn on 1890s maps, water doesn’t flow uphill!”  Lots of great stuff at Lost River Walks, so check out the website, and follow them on Twitter @LostRiversTO and also via founder and lost rivers force Helen Mills at her account @HMMLostRivers

Vanishing Point is the brainchild of Michael Cook, a resource of which “…emerged from a decade of underground research and photographic practice”.  The varied topics include topics of Daylighting Creeks, Parks and Stormwater Spectacles, Lost River Activism, and Celebrating Infrastructure Projects .  Cook continues, describing the work as ” a form of citizen geography, it has informed community groups, academic projects, and the official work of planners, landscape architects, engineers and archaeologists.”  This sort of comprehensive resource adds to the work of Lost River Walks with information and a wealth of interesting photography.  Lots to check out here, and also worth following Michael on Twitter @waterunder

The Don River Valley Historical Mapping Project is (was) a robust exploration of the Don River, “This project documents historical changes in the landscape of the Don River Valley. Drawing from the wide range of geographical information available for the Don River watershed (and the Lower Don in particular), including historical maps, geological maps, fire insurance plans, planning documents, and city directories, the project uses Geographic Information Systems software to place, compile, synthesize and interpret this information and make it more accessible as geospatial data and maps.”  It’s hard to tell if it’s still active or just the website hasn’t been updated, but most info stops in 2010, but still some great geospatial data, resources, maps, and other information related to the Don and larger Toronto hydrology.

A new? interactive map of the project provides spatial information to complement the work to date, and offers a way to interact with the data in new ways.

Another interesting take on how to use different methods for displaying the subject matter comes from Alex Meyers project “Uncovering the Creek“, a timeline that provides a “…study of the city’s changing landscape through a close examination of Trinity-Bellwoods Park and the Crawford Street bridges. This project is a virtual excavation of a hidden Toronto landmark that has been almost erased by the process of city building.”  A nice method of using a linear timeline with links to graphic resources and maps.

 

Additional Resources 

The group Human River was featured in the Lost Rivers documentary, and was featured doing an interactive walk, “during the annual story telling parade, participants wear blue becoming a human river and bringing the Garrison Creek back to life”.  It’s a cool way to use event to raise awareness plus looks like a lot of fun. It also looks like their website is both abandoned and hacked with lots of spamming links – so i grabbed this image quickly and then ran.  Not sure the current status.

Also mentioned in the Lost Rivers documentary, the Garrison Creek Demonstration Project by Brown & Storey Architects (from 1996!) envisions the use of the Garrison Creek zones for green infrastructure, positing that “… the existing natural watersheds, like the Garrison, can be used as sites for stormwater management pond systems. Not only can these connected pond systems serve to collect, treat and re-use stormwater locally, they can also act as a catalyst in the creation of a series of connected open spaces knitting both an urban and green infrastructure back to the waterfront to Lake Ontario.  The study documents several aspects of the Garrison watershed: the considerable amount of open spaces, their area and type, geological formations, existing storm water infrastructure underground, the areas of fill along the ravine path, and an abstracted locational plan for water retention ponds.”

A walking map of Garrison Creek evokes the story of the plans above, and multiple posts about Garrison Creek and a Discovery Walk also focus on Garrison Creek,

The Garrison Creek route is also referenced with some cool markers, as seen below:

Some additonal links include the Taylor Massey Project and Lost Creeks of South Etobicoke both smaller scale projects highlighting areas of Toronto lost creeks.  Also, more recently, Trevor Heywood posted a long series of walks on Twitter, with his explorations around the Yellow Creek, showing that the passion for exploration of Toronto hidden creeks is alive and well.  On that note, few more interesting images in the form of murals, first posted by @SheilaBoudreau of a Lost Rivers mural I’ve seen a bit; the second a map, posted by @tashmilijasevic both locations unknown to me but i’m sure folks in the area know where they’re at.

 

A Photographic Abundance

Photographers become drainers seems to be a theme in many cities.  In addition to Michael Cook from The Vanishing Point mentioned above, another photographer focusing on underground Toronto is Jeremy Kai, (Twitter @RiversForgotten   From his site: “His underground photography explores the concepts of urban watersheds and the methods in which cities interact with water and waste water. These processes go mostly unobserved by the general public. Kai hopes that by documenting the city’s lost rivers and overlooked spaces beneath the streets, he can awaken a new sense of mystery and mythology in the minds of urban dwellers everywhere.  His first book, Rivers Forgotten, is published by Koyama Press. It was released December 2011 and features his underground photography”

In a different bent is a recent exhibit entitled ‘Nine Rivers City’, From the site: “From west to east, nine rivers feed into Lake Ontario. View a map of the rivers here.  Harbourfront Centre has commissioned six contemporary visual artists to capture the complexities of each of these waterways that run throughout our urban landscape. Situated against the shoreline of Lake Ontario, NINE RIVERS CITY showcases how these extraordinary waterways connect us, attract us and mystify us.”  A clickable map showcases photographs spatially, such as Aaron Vincent Elkaim’s HWY 401 below:

The Don River East branch flows below the King’s Highway 401, also known by its official name as the Macdonald–Cartier Freeway, near Leslie Street by Havenbrook Park. The Don is formed from two rivers, the East and West Branches, that meet about 7 kilometres north of Lake Ontario.This section of Highway 401 passing through Toronto is a near constant river of cars, and is considered the busiest highway in North America.

Another take on this is Kathy Toth, who formerly had a page on her website ‘Watercourse (Buried Creeks)’ which seems to have been taken down, but does delve into the subject matter with her Hidden Toronto work, which aims to be reprinted soon.  Per her page: “The first edition of Hidden Toronto featured a selection of hidden infrastructure locations in Toronto, including bridges, drains and rooftops where graffiti has sprung up. Many of the locations are off the map and can be found with some searching or luck. Some of them are right downtown under foot, others are on the edge of greater Toronto area. I decided to showcase these spaces, and the artwork painted on them because they exist in an extremely narrow circle of composed of graffiti artists, a few photographers, and the odd individuals who either live in the surrounding areas. These environments have a unique character and the artists who work here take advantage of the serenity and isolation afforded by these surreal landscapes sometimes just 100m away from busy roadways.”

The distant fourth and final part of the Waterlines class featured the work of Eric Wagner and Tom Reese for their book Once and Future River: Reclaiming the Duwamish.  I unfortunately was out of town for work during this session, so don’t have the specifics on their actual presentation but wanted to close the loop on the class and explore this last resource through looking at the book itself (although they may have talked about something totally different).

The Duwamish is a fitting addition to the discussions of Geology, Archaeology, and the Ship Canal previously discussed, as it is the one and only river in the City of Seattle.  It, much like the Duwamish people, also best signifies the history of manipulation, exploitation and degradation, and the current challenges to restore both culture and ecology along this urban waterway.  It’s also in sharp juxtaposition to the current boom, as summaried by Duamish Tribal member and director of the Duwamish River Cleanup Coalition, James Rasmussen: “We need to always remember that the wealth of Seattle was created on the backs of the Duwamish River and the Duwamish People.”

Wagner discusses this evolution of the Duwamish River and people along with the greater City of Seattle through multiple essays.  They cover the inevitable growth leading the dispossession of the lands, the straightening and polluting of the river, the erasure of ecology and culture. It uncovers the long truth for Seattle about conquering nature, as has been discussed in the previous Waterlines lectures, here with Wagner mentioning it in the context of the Duwamish, “…to conquer something at least implies a respect for it… The Duwamish River cannot claim such dignity.” 

Now not even a river (classified a “waterway”) and a toxic Superfund site, the idea of restoration is difficult to imagine.  There is lots of hope and much work outlined in the book on the potential, in the words of William Jordan, to “heal the scars or erase the signs of disturbance.” 

There are a few maps early in the text, showing the 1856 Map of the region prior to the mass of European settlement, next to the 1958 Map, which shows development and channelization and virtual obfuscation of the natural systems.  As Wagner mentions, in the concept of restoration “In seeking such a reversal restoration becomes a question of time, and therefore a historical exercise as much as it is a moral or a spiritual one.  What point in a river’s past should we aim for?  When was it the best version of itself?  What processes from that period can we bring back now?”

A theme of the book then is put at the beginning of the introduction:

“We strive for a past we have never known, having only read about it, or seen in in faded pictures, or heard of it in stories about an old, shadowed river that once ran so full of life and magic that it filled the people who lived on it with awe, terror, and love.  When we arrived at that place — if we are capable of reaching it, if we can recognize it should we get there — we will have found a way of seeing something that has until now been ignored, dismissed, and very nearly lost: a river from end to beginning.”

Subsequent chapters cover the history of the River through a Salish parable called the “Epic of the Winds”, and the importance of this place in the life cycle for Chinook Salmon; land erasure and land making, the industrial heritage, large scale camouflage to win World War II (seen below, the ‘streetscape of a village draped on top of Boeing Plant 2 along the Duwamish, the facility constructing B-17 Bombers, to throw off potential attacks.

image via Boeing

This patriotic and economic value of the altered Duwamish in Plant 2, Terminal  and hundreds of other comes with a legacy of toxicity the persists and will continue for millenia.  In further essays we learn about poet Richard Hugo‘s regionalist riffs on the Duwmaish, and learn about John Beal‘s tireless work to save Hamm Creek, and modern day restoration efforts including hatcheries.  Will the River rebound?  How long will it take? Who knows, but as Wagner mentions:

“…the Duwamish River has always been a place to test the surprising range of the possible.  Settlers looked at acres of mud flats and forest and saw a city. City engineers looked at a floodplain and saw a waterway. Businessepeople looked at a waterway and saw a waste management system. Now, we look at a Superfund site and see a healthy river filled with fish that are safe to seat.  All those earlier versions came to pass.  Why should this latest not as well.”

While the first half is well illustrated with Tom Reese’s photos, the second part of the book is exclusively devoted to the photographs, capturing the range of themes, including the river itself, as well as the degradation and activities around its restoration.  Bolstering the text, this beautiful, damaged place offers sorrow as well as hope.  As Reese mentions in the Coda, “The Duwamish also informs our subconscious desire for connection and our intensifying undercurrent of worry.  it can transport us to places within and beyond our own lives, reminding us what is precious, asking for our devotion.”

Some of the photos from the book are peppered through this post are also on his website, so peruse on over there to catch more imagery, or just buy the book because it’s a great addition and has even more images that you’ll come back to more than once.

An extended video probably will help fill in some of the blanks also – from about a year ago at Town Hall  “…featuring Tom Reese and Eric Wagner, co-authors of “Once and Future River: Reclaiming the Duwamish”; James Rasmussen, Director of the Duwamish River Cleanup Coalition; and Lynda Mapes, Seattle Times Environmental Reporter”

 

Header image  Copyright Tom Reese – “Last natural bend in lower Duwamish at Kellogg Island” – all other images, unless noted, are by Reese as well.

River Piracy sounds like an exotic form of stream based pillage and plunder, but rather refers to the reorientation of stream flow from one channel to another.  Also known as stream capture, the causes vary, and include tectonics shifts which changes slope, natural dams (landslide or ice), headward and lateral erosion, karst topography, and glacial retreat.   Notable ice dams have diverted rivers, of note is the River Thames, which was shifted 450,000 years ago cause it to

A recent set of stories about the Slims River in the Yukon territory illustrates the last of these points, where the retreat of the Kaskawulsh glacier and it’s shift from the Slims River to the northwest and into the adjacent Kaskawulsh River to the southeast.  The phenomenon isn’t uncommon, but the pace in which this ‘theft’ occurred is notable: “Such a transformation has occurred numerous times throughout the planet’s geological history – often due to gradual erosion or the movement of a fault – but has never been observed to occur as suddenly, happening over just a few days in May 2016. ‘Geologists have seen [evidence of] river piracy before, but nobody to our knowledge has documented it actually happening [within] our lifetimes,’ explains Shugar, Assistant Professor of Geoscience at the University of Washington, Tacoma.” The image below shows the “aerial view of the ice canyon that now carries meltwater from the Kaskawulsh Glacier, seen here on the right, away from the Slims River and toward the Kaskawulsh River.”  

A map of the area shows the relationship of the river and the shift, which short-circuited a longer path through the Kluane River into the Yukon River and eventually the Bering Sea, now connecting to the Alksek River and flowing into the Pacific Ocean.  From a global perspective the flow doesn’t mean much, but on a local scale the impact is more acute.

From the article in the Globe and Mail, “Climate change stole a Yukon river almost overnight, scientists say. Here’s how“, which mentions the process at work:

“That water now flows into the Kaskawulsh River, a tributary of the Alsek, which runs southward to the Pacific. Following this route, it reaches the ocean some 1,330 kilometres away from where it would otherwise have ended up. Signs of the rerouting have been observed on both sides of the mountainous divide. Gauges on the Alsek River reveal that it experienced a record discharge last year. Because the river mostly flows through parks and protected lands, the increase has had no immediate human impact. On the Slims side, the effect of water loss is more obvious. Last summer, Kluane Lake dropped a full metre below its lowest recorded level for that time of year. The reduced inflow from the Slims spells a huge change for the 65-kilometre-long lake, with implications for nearby communities and visitors who access its waters for fishing and other activities.”

The quality of the Lake ecosystem is one issue also, as mentioned in the Guardian article “The river stolen by climate change”, quoting scientist Jim Best:  “The dramatic switch was caused by the rapid retreat of the Kaskawulsh glacier – thanks to climate change – which caused the flow of the meltwater to be redirected, and prompts questions about the impact it could have on the surrounding Yukon territory. Best points out that while much of the southern part of the territory is ‘sparsely populated’, and therefore potential flooding caused by the extra water is unlikely to cause any ‘real human impacts’, the opposite issue could be a cause for concern further north.  ‘If Kluane Lake levels go down,’ he predicts, ‘the lake could thus have no inflow and no exit flow, which would radically alter lake water nutrients and circulation, and this may impact on the lacustrine ecology. In addition, if the lake outlet were to dry up as a consequence, this river would be dry or far lower and thus the few habitations along it would be affected.’”

The dry valley left over, in this case the Slims River, is referred to as a wind gap, and scientists have discussed the potential issues erosion and dust storms.  As noted in the CBC story, “Retreating Yukon glacier makes river disappear“, the river is: “…prone to dust storms.  “It’s certainly not unusual to see rapid drainage changes in and around these glaciers. It’s a common situation,” Bond said.  “Until vegetation really starts to stabilize that floodplain, it’s going to be a dusty place, I’d imagine … It will be a really interesting study to see how that floodplain evolves in the next ten years or so.”