Two French rivers disappear underground in cracks and sinkholes | Hacker News Reader

Two French rivers disappear underground in cracks and sinkholes

strangesounds.org

225 pointsEarth_Change34 comments

An interesting and little-known fact is that the Danube in Germany does exactly the same for roughly 155 days per year [1], which is called "Donauversinkung" ("swallowing of the Danube"). Between the towns of Immendingen and Fridingen on the Swabian Alb the water just disappears underground [2]. This started to happen around 300 years ago, and until the 1870s nobody knew exactly where it went. They then did experiments with Uranin and ultimately proved that the water re-surfaces in the Aachtopf [3]. Now, the water from the Aachtopf flows directly into Lake Constance, therefore into the Rhine, and therefore into the North Sea. Normally, the Danube flows into the Black Sea, which essentially means that on roughly 155 days per year, the disappearing water moves the European watershed [4], which I find highly fascinating.

E: as the Danube laters flows through the once independent state of Württemberg, and the Rhine through the once independent state of Baden, there was also a nice court battle between them because of the lost water in the 1920s - the "Donauversinkungsfall" [5] ("the court case of the swallowing of the Danube")

[1] https://en.wikipedia.org/wiki/Danube_Sinkhole

[2] https://upload.wikimedia.org/wikipedia/commons/2/20/Donauver...

[3] https://en.wikipedia.org/wiki/Aachtopf#/media/File:AachTopfP...

[4] https://en.wikipedia.org/wiki/European_watershed

[5] https://de.wikipedia.org/wiki/Donauversinkungsfall

Am I understanding correctly that the Danube always seeps into the ground near Immendingen (since 300 years), but if the conditions are dry enough there is not enough water to flow past this sink hole, so all of it drains into the European watershed?

It should be noted that this only the first few hundred meters of the Danube and it's relatively flat there so the exact way the water sheds is probably always subject to changes up there (at least across large spans of time). There are relatively small masses of water that flow up there, so things are not set in stone as much (literally).

This is correct. The main sinkhole is roughly 3 km downstream from the source. Disappearing water was first noticed 300 years ago, and the first total disappearance was in the 1870s. It is expected that this process will eventually make a small creek [1] the new source river of the Danube over the next 1,000 to 10,000 years.

There is a group of hobby enthusiasts who are digging into the cave system since 1990 [2], expecting to find a cave containing an enormous underground lake, as the amount of water disappearing into the underground is much larger than the amount of water later carried by the Aach. AFAIR, they managed to finally reach the underground river ~15 years ago. arte did a documentary about them, called "Die schwarze Donau" ("The black Danube"). You find it on YouTube, but it's in German.

E: here is an image of the underground Danube found by the hobbyists mentioned above after 13 years of digging: http://www.wolfgang-bauer.info/pages/reportagen/schwarze_don...

E2: if you are interested in the subject, I highly recommend visiting the Skocjan cave in Slovenia, which was also formed in a karst region by an underground river. I found the visit to be an almost surreal experience [3][4][5].

[1] https://de.wikipedia.org/wiki/Kr%C3%A4henbach_(Donau)

[2] http://www.wolfgang-bauer.info/pages/reportagen/schwarze_don...

[3] https://cache-graphicslib.viator.com/graphicslib/thumbs674x4...

[4] https://cdn.tourismontheedge.com/wp-content/uploads/2011/02/...

[5] http://www.pension-silvia.si/images/activities/the_skocjan_c...

interesting. You can visit a similar cave system with an underground river (and go on a boat ride) in Czech Republic https://en.m.wikipedia.org/wiki/Punkva_Caves

[1] links to the main Wikipedia page on the phenomenon as well:

https://en.wikipedia.org/wiki/Stream_capture?oldformat=true

For the Doubs, this is well-known that it is losing water under its bed and that the Loue river is this water coming out at a different point.

You can see the source of the Loue[0] on the Wikipedia page. The river is basically coming out of the mountain with already a very high flow rate. This is one of the nicest river in the east part of France, it is a pleasure to walk along or navigate it.

Edit: Found videos[1] where you can see the holes sucking the water in the river bed.

[0]: https://en.wikipedia.org/wiki/Loue

[1]: https://www.estrepublicain.fr/edition-haut-doubs/2018/07/31/...

> This connection with the Doubs was only discovered in 1901 when a spillage from the Pernod factory into the Doubs was transmitted into the Loue.

Suits my definition of drinking water.

This is one reason why it's prudent to scout rapids before running them. For example, sections of the Brule River in Minnesota are runnable above and below Devil’s Kettle.[0] And by the time you saw the drop, it'd be too late to avoid the falls or sinkhole.

Even so, sinkholes can be subtle enough to miss, and still fatal.[1] Karst is some dangerous geology for boating. Although riverbeds are generally quite smooth, which is pleasant enough if you go for a swim.

0) http://www.startribune.com/scientists-think-they-ve-solved-t...

1) https://www.boston.com/news/national-news/2018/06/12/sinkhol...

No discussion on why the cracks and sinkholes appeared. I'm looking around on Google but it seems there's very little information (in English anyway).

It's due to the karst topography.

There is very likely a sizable cave that exists beneath the river bed, the entrance to which had heretofore been clogged by sediment, which has been washed away by recent rains. Could also be that a choke deep in the cave itself has been washed out, joining it to another cave, which provided enough throughput to drain the river entirely underground.

A Karst[1] geology usually consists of water-soluble rocks and sediment. Over time, water dissolves the rock and creates new passage ways, both above and under-ground.

Sometimes this can be affected by human activities(such as mining, as has happened with aquifer withdrawals and phosphate mining in Central Florida and Clear Springs[2]

[1] https://en.wikipedia.org/wiki/Karst

[2] https://en.wikipedia.org/wiki/Kissingen_Springs

Eurasia has lost enough groundwater to affect the movement of the North Pole. That's my theory: groundwater is being consumed by people faster than it's being replenished.

https://www.jpl.nasa.gov/news/news.php?release=2016-100

So that sounds nuts (and suspectedly alarmist/political) but it's a nasa.gov link, so...

After reading, it is true but indeed needlessly alarming. Changing underground water levels are influencing the rotation of the Earth, but it's mainly happening in India and East Europe, way far from the east of France.

Key quote: "The researchers found the answer in Eurasia. "The bulk of the answer is a deficit of water in Eurasia: the Indian subcontinent and the Caspian Sea area," Adhikari said.

The finding was a surprise. This region has lost water mass due to depletion of aquifers and drought, but the loss is nowhere near as great as the change in the ice sheets.

So why did the smaller loss have such a strong effect? The researchers say it's because the spin axis is very sensitive to changes occurring around 45 degrees latitude, both north and south. "This is well explained in the theory of rotating objects," Adhikari explained. "That's why changes in the Indian subcontinent, for example, are so important.""

"groundwater is being consumed by people faster than it's being replenished."

Well, allmost all the water that gets consumed by people still end up in the rivers afterwards ...

My neighborhood lake disappeared in a similar manner. We have Karst geology in Missouri. Might be similar.

https://en.wikipedia.org/wiki/Karst

I grew up in the Risle Valley, that is pictured in the video. I can confirm that we have the same geology. For only a few years, the river is disappearing every summer, which sounds surprising in a global warming context. But no big deal here, just geology.

The article says it's karst.

(Sinkholes occur when an already-significant underground cavity, typically formed by water dissolving the rock, gets close to the surface and the roof falls in.) https://en.wikipedia.org/wiki/Sinkhole

Lake Chesterfield?

Yep! We've since moved, but they have the lake drained right now to try to figure out how to make it stop leaking.

I feel sorry for the "lakefront" houses that have a big empty pit in their back yard. They've tried several times to fix this, and I'm pretty certain that there was a special assessment associated with each attempt.

From the article:

> geologists say the river disappearance is due to large cracks in the karstic riverbed, which empty the river underground like a siphon. It is perhaps the important spring floods that washed away the sediment patches that blocked the holes and fissures.

Quite a good discussion on the sinkholes, caves, lakes, earthquakes and fault lines.

https://www.quora.com/What-is-a-sinkhole-when-it-is-in-water...

It says 13 days ago, but the linked video is from 2012?!

My local newspaper is the same way.

Talks about a very visual thing .... doesn't have any photos.

It's crazy because all those media companies fired their photographers and in the age of the internet ... PHOTOS AND VIDEOS ARE IMPORTANT!

Similar situation for the Popo Agie River near Lander, Wyoming. Only it resurfaces soon after going underground.

[1] https://en.wikipedia.org/wiki/Sinks_Canyon_State_Park

This pattern is fairly common when there is karstic geology, but also happens in other cases: https://en.wikipedia.org/wiki/Subterranean_river

I don't know how common seasonal variation is (per the other comment about the Danube doing a similar thing to the French river).

In Florida, one of the branches of the Suwannee disappears into the Santa Fe River sink at O'Leano [0], supposedly travels 5 more miles underground, then comes back up three miles away at River Rise [1].

[0] https://www.floridastateparks.org/park/Oleno https://www.youtube.com/watch?v=0JiXOk1pXus

[1] https://www.floridastateparks.org/park/River-Rise

Cached: http://webcache.googleusercontent.com/search?q=cache:PpWRy3i...

In Detroit the buried rivers are called the ghost waters. There has been talk on and off about resurfacing some of them where practical. Can you imagine a gondola ride in the Motor City? Something that I'd sure like to see in my lifetime.

http://www.modeldmedia.com/features/ghostwater413.aspx

Sensationalism all the way. At least one of the rivers has seen it already in 1 976 (quite recently as far as Geology and Topography go) and several other rivers in several parts of the world do the same or similar things.

Worst case scenario, the water permanently goes elsewhere, either to an aquifer or to another river or lake. People adapt. End of history.

>End of history.

So, you are saying this is an Armageddon level event?

This sounds related to Eurasia losing enough groundwater to affect the movement of the North Pole.

https://www.jpl.nasa.gov/news/news.php?release=2016-100

Read the article. It's from the area's Karst topography.

Same with the Lost rivers in Idaho

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