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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...




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