Meandering Streams for Dummy Geography Students

Meander cutoff and oxbow lake

One of our staffers at the Antisocial Network had a Christmas present for all her coworkers: a new content farm website to mine for freelanced crapola. While checking on an old article about oxbow lakes, she ran across similar dumbassery someplace no one at ANHQ had ever pinged before: ThoughtCo.com. Let's take a look at the travesty "award-winning freelancer" and self-described geographer Matt Rosenberg visited on the same topic in "Oxbow Lakes." The post was originally at About.com before the site changed its name to Dotdash and created niches...

Oxbow lakes, for those of you who don't know the term, are a feature of mature meandering streams. The more mature a meandering stream and the lower its overall gradient, the more sinuous its channel becomes. As meanders become ever larger, it's possible for one meander to join an adjacent loop of the channel by eroding across the narrow neck of land between them. Since water will follow the shortest route between two points on a slope, the river abandons the section of old channel. The old loop is still a water-filled depression, however: a lake shaped like a giant U. That's what an oxbow lake is.
Rosenberg's explanation, however, doesn't quite say that: instead, Matt tries to tell us that,

"Rivers flow across wide, [sic] river valleys and snake across flat plains, creating curves called meanders. When a river carves itself a new channel, some of these meanders get cut off, thus creating oxbow lakes that remain unconnected but adjacent to their parent river."

Rosenberg's intro there is deficient in several ways. First, not all rivers "flow across wide, river valleys and snake across flat plains"; only those that are classified as mature streams meander. Second, forming the cutoff between two meanders does not mean that a "carves itself a new channel"; only that it modifies the existing channel.

We'll buy into his explanation of how meanders widen, although we would think that a section entitled "How Does a River Make a Loop?" should at least mention why rivers start to bend instead of, "Interestingly, once a river begins to curve..." Shouldn't he mention something about sediment load, equilibrium, stream gradient, or water velocity? Apparently, the Wikipedia article from which he harvested much of his factoids doesn't mention any of those factors; he should have looked down deep in the Wikipedia article on meanders...

Matt also had some rather confusing things to say, including, "Eventually, the loop of the meander reaches a diameter of approximately five times the width of the stream and the river begins to cut the loop off by eroding the neck of the loop. Eventually, the river breaks through at a cutoff and forms a new, more efficient path." We have no idea where he came up with that "five times" stuff. Even though he plucked most of his terminology (and his examples) from the Wikipedia article on oxbows, that's not in there anywhere. That's OK, though: the sentence doesn't make much sense, anyway.

So once again we have a freelancer pretending to know all about a topic even though he just plucked most of his information from Wikipedia. If that's not a Dumbass of the Day, we don't know what is!

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