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I recently rafted the San Juan river in Southern Utah, which flows into the Lake Powell reservoir. When the water levels in Lake Powell were very high, it extended far upstream into the San Juan River. This caused the river to stagnate and deposit enormous amounts of silt in the canyon.

When Lake Powell water level subsequently dropped, the river carved new meanders through the resulting silt beds, but within the much larger meanders that form the canyon. (Satellite Imagery from Google Maps)

enter image description here

The San Juan doesn't flash flood anymore due to the flow regulation of the upstream Navajo Dam, so it hasn't been able to wash out the silt.

Apparently "meanders in meanders" is not a unique phenomenon as Anders Sandberg has also captured it here, but I don't know where he took this picture.

enter image description here

Question: Can "meanders in meanders" also form naturally? How does this happen? Also, if there is a more scientific name for this phenomenon, it would be helpful.

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    $\begingroup$ @AndersSandberg Perhaps you could shed some light on this question? $\endgroup$
    – Connor Garcia
    Commented May 4, 2022 at 15:50
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    $\begingroup$ FWIW, the image by Sandberg is of the White River, UT, at about 39.96 N, -109.21 E. This is about 30 km downriver of the Kenney Reservoir, CO. $\endgroup$
    – Matt Hall
    Commented May 11, 2022 at 15:03

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Yes.

Here's an example of a river in Siberia (at about 62°08'N 83°06'E) that appears to be unimpinged by human activity. It's a bit hard to see both scales at once, but the river meanders all over the place.

A meandering river in Siberia I'll refer you to Peter Jansson's answer for more of an explanation, but the first order idea is that the meandering valley (the large-scale landform) forms under one set of conditions and the meandering channel (the small scale channel) under another. Those conditions might change seasonally (as in Utah) or historically (as I suspect is the case in the Siberia example).

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    $\begingroup$ Wow, this is a great example! It looks like there are lots of older oxbows and other post-meander features under the current channel. Also, I couldn't find a specific name for "meanders in meanders," but the large-scale channel is often referred to as a "meander-belt." If a historic change happened here, I wonder if it was a gradual reduction in flow down the channel. $\endgroup$
    – Connor Garcia
    Commented May 11, 2022 at 16:09
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    $\begingroup$ Wondering how much random searching on Google Maps/Earth you had to do before you found it! Randomly scrolling maps is a great pasttime :) $\endgroup$
    – JeopardyTempest
    Commented May 11, 2022 at 16:40
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    $\begingroup$ @JeopardyTempest Not too much (if there is such a thing). Siberia, Alaska and the Amazon basin are my go-to's for meanders, and I suspected there would be too many dams in a lot of other likely places. [Thanks for the image edit!] $\endgroup$
    – Matt Hall
    Commented May 11, 2022 at 17:07
  • $\begingroup$ @ConnorGarcia My old geomorph textbook called them "compound meanders" but didn't give any examples. $\endgroup$
    – Spencer
    Commented May 16, 2022 at 20:19
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In the case that you show there are so-called incised meanders cut into the bedrock in which material has been deposited when lake levels have been high. When lake levels have dropped the sediments and the slope of the valley is favourable for meandering.

Meandering rivers form at low slopes and in fine partially cohesive sediments. Thus the meandering patterns says much about the slope of the former lake bed and the type of sediment laid down on the lake bottom. With steeper slopes or with diffreent grain sizes, the meandering may not be the resultring river pattern.

The observation that a meandering river has developed in an old incised meandering river valley is mainly fortuitous since the present river does not require a wide valley to develop meandering. If the river would have larger discharges it likely would require a wider valley to develop such intricate meander patterns. At the same time the bedrock valley floor is likely at some depth below the current valley surface so the large scale valley meander pattern may become more complicated at depth.

A good and recent (at the time of providing the response) summary of meandering is:

Hooke JM, 2022. River meandering. In: Shroeder, JF (ed) Treatise on Geomorphology (Second Edition). Oxford, Academic press. 480-516.

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    $\begingroup$ +1, This is excellent information with a nice reference, but I am not sure it actually answers my question. For the lower San Juan, the meanders in meanders appear to be anthropogenic: the result of human behavior. Does this phenomena also occur naturally? $\endgroup$
    – Connor Garcia
    Commented May 5, 2022 at 16:22
  • $\begingroup$ @ConnorGarcia Ok, the meandering is a natural phenomena, the lowering of the water level is a human effect so the natural processes work as usual it is just that they are forced by human interaction. The meandering process as such cannot be produced by humans except momentarily if one, for example digs a meandering channel for the water to flow in. The water flow will inevitably return the river channel to wehatever is natural regarding slope, soil material etc. $\endgroup$
    – Peter Jansson
    Commented May 5, 2022 at 16:33
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    $\begingroup$ I understand and agree about the San Juan. My question is not about the San Juan, though. My question is if "meanders in meanders" can occur without human intervention. So an answer to this question could be a satellite image of "meanders in meanders" on an undammed river. $\endgroup$
    – Connor Garcia
    Commented May 5, 2022 at 17:17
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    $\begingroup$ @ConnorGarcia, I fully understand but the answer still stands because the process works regardless of location and only depends on local conditions. It is thus necessary to look at the local conditions and see how they fit into the scheme of, in this case, fluvial conditions. The bottom line is that the processes as far as we understand them work everywhere and only local conditions can determine what actually happens. $\endgroup$
    – Peter Jansson
    Commented May 5, 2022 at 18:06

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