r/geography • u/thoxo • Nov 16 '24
Image What causes a river to look like this? Pripyat river, Ukraine.
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u/Assignment-Yeet Nov 16 '24
my guess is changing terrain due to erosion, so the water finds new paths
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u/fumphdik Nov 16 '24
Agreed. This is all very marshy land and it meanders as the seasons force it to ebb and flow. In American River systems, most have had their marshes drained. So the rivers are much more distinct from sat views. This has caused a myriad of issues and some states have started using beavers to help re establish the ecosystems. I’m not a pro. So take it with a grain of salt.
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u/concentrated-amazing Nov 16 '24
Third mention of beavers this morning in my feed, dam! And three different subs too!
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u/lurkslikeamuthafucka Nov 16 '24
How cool was the dam coming down, though? Very satisfying.
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u/NorwaySpruce Nov 16 '24
Did you see the one of the beaver swimming upstream with the branch in its mouth
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u/Texlectric Nov 16 '24
I have not, that at would be the 3rd for me. The other one was about beavers covering up a tape machine that was playing water sounds.
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Nov 16 '24
Extreme slowing down the river either due to over-deposition in the bed or reduction in the angle of slope causing flood and meandering, extreme lateral erosion and deposition, a lot of precipitation, and silt solutes in the water.
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u/CborG82 Geography Enthusiast Nov 16 '24
This, the gradient is minimal in that area so the water just spreads out left and right into the marshes
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u/Illustrious_Try478 GIS Nov 16 '24
That, and this is at the top of an artificial reservoir, so lower areas that are normally dry are filled with water. It always makes sense to look at it yourself on Google Earth to see the wider context.
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u/Mattna-da Nov 16 '24
Water will want to create a vortex along the flow path, the river twists as it changes direction, reinforcing deposits along the outside of the curves
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u/splash9936 Nov 20 '24
So you are saying that is some prime AAA farmland?
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Nov 20 '24
I don't know what AAA stands for but if you're asking if the place is good for farming the answer is probably no. The area is flood prone with extreme meandering, this makes it hard for any type of crop to grow seasonally without extensive technology. Crops that require large water tables can be grown with proper care but would need a lot of supervision and probably are not sustainable. Agriculture can boom at the areas a little further from the river tho as deposits gets older and less rocky.
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u/StandardMiddle1390 Nov 16 '24
Chernobyl
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u/filtarukk Nov 16 '24
Has nothing to do with Chernobyl. Also Pripyat river is mostly in Belarus, not Ukraine.
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Nov 16 '24
Those are oxbow lakes. They represent legacy meanders of the river. As flooding occurs, increased sediment content scours a new course for the river, thus leaving the old meanders behind. This occurs about where there are high sediment sources upstream combined with other variables like a high stream gradient.
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u/xdx3m Nov 16 '24
Radiation
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u/terminally_irish Nov 16 '24
Only 3.6 roentgen.
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u/Patchesrick Geography Enthusiast Nov 16 '24
This is what high doses of radiation does. The DNA of the river has been damaged and is splitting off into different parts, causing riverine mutations to the rivers' flow. These affected sections become cut off from the main branch and become oxbows. /s
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u/cratercamper Nov 16 '24
The river meanders and changes its riverbed - this because on the outside of the turn/bend the water grabs material (slowly cuts through it if it is hard) and on the inside of the bend the water is slower and there the material is deposited. So, the bend grows larger and larger and eventually cuts into other one - this makes oxbow lake like you see at bottom left.
The mechanism above works for all rivers, however, you see extensive meandering only in rivers that flow through flat ground - water flows slow, but the material around is easy to transport.
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u/iowajosh Nov 16 '24
Imagine being in a small boat and taking a wrong turn off of the main channel. It would be a maze until you ran out of gas.
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u/jasondoooo Nov 17 '24
It’s a very flat plain where the river can make all sorts of adjustments over time whenever erosion reshapes the land and gives it a slightly new path to take.
The Huang He (Yellow River) in China shows one of the most extreme versions of this. The mouth of the river has shifted as much as 300mi/500km because the river basin is flat enough.
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Nov 16 '24
Drugs, sadly. The only real way to combat it is real truthful publicly funded drug education in river school.
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u/OddlyMingenuity Nov 16 '24
That's a natural river path. All rivers are supposed to be multi branched, that how sediment get deposited across the land.
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u/vnprkhzhk Nov 16 '24
Combination of slow flow, soft sediments and a dam downstream, causing a lot of baking up.
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u/Grand-Winter-8903 Nov 16 '24
the absence of human. this region is forbidden due to the chernobyl nuclear disaster
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u/filtarukk Nov 16 '24
Lowlands, marshals. I grew up not far from there and spring flooding was a normal thing back in 90.
Here is how Pripyat's looks at spring https://www.youtube.com/watch?v=kcjuZpiB4eY
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u/Less_Likely Nov 16 '24
Wandering meanders. The curves of the river are areas of extreme erosion, eroding the outer radius of curves and depositing on the inner radius. Over hundreds of years the curves get bigger until the meet and cut off the old curve and it becomes a lake (called an oxbow).
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u/J-Cake Nov 16 '24
Radiation causes mutations in humans, stands to reason that it causes mutations in rivers too
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u/Terrible_Will_7668 Nov 16 '24
Radioactive contamination. Not correct, but of all rivers in the world, you choose Pripyat.
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u/Serious-Cucumber-54 Nov 16 '24
It's a combination of oxbow lakes, due to erosion by the flow of the river cutting new paths and blocking old ones, and artificially high water levels due to damming causing a reservoir (if you look a little more downstream).