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Nov 13 2012

A Riverman Reads the River

Steve Gough left an enlightening comment on “Learning the Language of Rivers II,” which I don’t want folks to miss. It goes some way towards answering some of those questions the river raised:

From a guy who’s analyzed hundreds of miles of stream channels (I’m getting so old), many of them in human-impacted places like this, here goes: The line of rocks is definitely human-placed; and the angular rocks may have some from nearby rock that hasn’t been water-worked. Also in actively-incising/migrating channels in urban areas we see angular bank stuff eroded into streams. The fines/gravel mix is from either a damming episode (either logjam or anthropogenic), or was mixed and placed by a big yellow machine. Probably the cut-off was machine-made, too, and may be related. The historic aerials will tell you an interesting story I’ll bet. And at one/both ends of that dry channel you will find telltale berms/levees built to keep the channel out of it. Hope I get to look at one of these with you some day!

Me, too! I have to say, that’s like the possibility of jamming with Roger Clyne, or writing with C.S. Friedman. I’d go for some of that!

Mini-waterfall on the Marys River.

Mini-waterfall on the Marys River. Humans did it!

So we’ve an answer from an expert – that’s definitely a human-caused feature. Sweet!

I’m pretty excited by Steve popping by here – I’ve had my eye on one of his stream tables for ages. First thing I’m buying when I finally manage to afford a place with a garage or nice little outbuilding. Can you imagine how much fun it would be to throw neighborhood stream parties? My astronomer neighbor used to have herds of kids over to gaze at the stars through his backyard telescope, and that experience certainly got me enthusiastic about science. A stream table could be just an excellent an introduction. And I have a sneaking suspicion it would captivate a few adults, too. And in an area where stars are all too often blockaded by clouds, but you can see running water almost everywhere you go, it would have the potential to change the way we relate to the rivers around us.

Anyway. That’s one of my dreams. The other is to get out there on the banks with Steve and start speaking River more fluently. Thanks to him, all of us just learned a few more words!

10 comments

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  1. 1
    Lyle

    I remember play stream table with snow while growing up in the midwest. During the time it melts often there are water streams and one can see how the water erodes the snow. (Since the water is at the same temp, it takes a lot of water to thaw snow at 80 cal/gm. Often you had ice in addition to play with.

    1. 1.1
      Trebuchet

      And I’ve enjoyed watching the rivulets on the beach as the tide goes out. It can be fun to just move a little sand around with your shoe to see how the stream adjusts. It can take surprisingly little to cause it to abandon a pretty good channel and make another.

  2. 2
    F [i'm not here, i'm gone]

    You might like a series of posts at Research at a snail’s pace with titles beginning Hacking the Em2.

  3. 3
    rq

    We did a lot of stream exploration and discovery (and also contributed quite a bit to riverbank erosion) on the Rouge, when I was much younger. The one swimming spot publicly available was on a fairly steep yet sandy embankment, and it was so awesome to make all kinds of pathways for the water, starting from the very top. We’d usually start with a little trickle, just to see where to begin digging, and then the fluvial works began: twists, turns, dams, dikes, tunnels… Every now and then, due to occasional flooding (someone always managed to drop the entire bucket at once instead of pouring a nice steady stream), these things would shift and change and we would develop them into even more, greater, more elaborate features.

  4. 4
    rq

    This is kind of a propos of nothing, except you doing a series on rivers. It’s a short video about a paper festival in a historic papermill town, but the really cool bits in the video are where you can see some of the Latvian river geology (sandstone cliffs with caves, the lower plateaus). All part of the post-glacial landscape here.
    Also, I came across a Latvian term ‘zvoncs’ to refer to a glacially deposited hill with a lake in the top, in cross-section it looks like this. What’s the English word for the feature? The internet dictionaries I use don’t have the term and I don’t own any good Latvian-English geology dictionaries (I doubt there are any). Mm the terms at the bottom are (from top down):
    - glacial lake clay
    - glacial lake sand
    - incline deposits
    - glacial deposits – rocky sandclay

    **Please note my technical terms are crap, these are direct translations. If I should ask these questions better by email, let me know.

  5. 5
    F [i'm not here, i'm gone]

    Zvon is a bell, so I would imagine it is a kame with its own kettle in it*. BTW, English words for lots of geological features aren’t English at all, but frequently taken from whatever language with which a feature was first geologically described, or a language which had a name for a local feature. (Drumlin, for instance, is from Irish, thalweg from German, moraine from French, kame from Scots (or maybe Scottish)…)

    *This is almost certainly an incorrect usage of kettle, but it amuses me. Kames tend to be a bit irregular, and a depression in the top would not be unusual.

    1. 5.1
      rq

      Ah, thanks, I’ll look into those words today and see if they match up. Someone should write a linguist’s dictionary for geology.
      ‘Zvoncs’ in Latvian actually doesn’t mean much except this geological feature, but the root is from the word for ‘bell’, yes. Using google for zvoncs turned up other languages where it also means bell, but no geological features; would not have guessed that ‘kame’ is the equivalent. :)
      (And yes, I’d noticed that a lot of words in geology – at least in the glacial geology that I’m looking at – don’t come from the more-accustomed Latin or Greek roots, but from the local European languages, and quite a few of these features are Scots or Irish. Which makes sense, considering their topography.)

      1. Dana Hunter

        Remind me of this thread when I get round to all the glacial geology I’ve been meaning to do! I might be able to find out more – and write up a nice linguistic thingy.

        For now, it’s off to another MSH post for moi… You lot will love it, things are blowing up. ;-)

    2. 5.2
      rq

      For F:
      The caption of this photo, I believe, is using both ‘kame’ and ‘kettle’ and all other terms properly. ;) Perhaps you will be amused.

      And yes, Dana, I’ll try to remember. Due to a somewhat oblique request from someone to have a geological overview of the territory of Latvia, I’ve been looking into this stuff, and I think I’m running into your problem… Lots of stuff, lots to know that I don’t, and just so little time. I admit, I have gone from someone who used to think Latvia geography somewhat boring (come on, it’s flat), to thinking it’s vaguely interesting (hey look, we have cool river valleys!), to being quite quite impressed with the features we do have and how they developed (those sheets of ice were how thick???). :)
      But that language thing, yes, that could be a very interesting research topic, probably something about the development of geology as a field.

  6. 6
    Steve Gough

    Thanks for the props Dana! And we’ll do our best to get you a model.

    Another possibility is that a utility line, usually sanitary sewer, crosses under that pile of rocks– see any black iron in there? And that would explain the weird soil/rock mix; a trench would have been dug to lay the pipe in, and then backfilled with mixed material. Very common thing in urban/suburban areas. Kids or even public works people sometimes pile stuff on the exposed pipe.

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