Flashy River!

You know you’re not from a “normal” part of the world when you glance over the side of the bridge and exclaim, “Wow! There’s water in the river.” And boy was there ever! A week ago Saturday, a line of thunderstorms dropped lots and lots of hail and rain on the headwaters of several branches of the Red River. When I crossed the river down near Esteline around noon on the next day, so much water had flowed downstream that the river filled the banks and had large waves on it. Those people passing through from out of state to the east probably wondered if someone was reenacting the Plagues of Egypt. The river really did run red, as if with blood. (Thus the name.) High, wide, muddy, and dangerous, the water raced downhill, headed for the Gulf of Mexico.

Two days later, when I crossed it again, more sand and mud than water met my eyes. The Red is a wide, braided stream because of all the sediment it carries (and the relatively flat land it flows over). The main channel had some water in it as it snaked and swept back and forth across the valley floor. But far more bare mud and sand met my eye. Now, I wouldn’t go walking through the valley, because of quicksand, but I nodded to myself. It looked like a normal local river. Very flashy.

The hydrograph of a flash flood looks like this:

This is from a pretty good paper at ResearchGate.net, “Flash Flood Hazards” a chapter from a water management book, by Denes Loczy, Szabolcs Czigany, and Ervan Pirkhoffer  The X-axis is time duration of event, and the Y-axis is flow volume. You notice that instead of a nice slow rise, smooth peak, and gradual fall (a stream with snow-melt as a source, for example), you see a vertical increase, rough curve, and then only slightly slower flow drop. That’s a flashy stream. In the US, most Great Plains, High Plains, and western streams are flashy, prone to flash floods. Fast come, fast go.

Flashy streams are useless for, oh, hydropower, irrigation, running mills, sailing boats up, you know, economically useful things. They come, they go, they go away. Not helpful, unless you can trap that water. In some cases, they are lethal, as the poor folks discovered last year when the far upstream rainstorm caught people in a slot canyon in Utah. In the case of the Red, Canadian, Picketwire, Platte, Green, Colorado (both of them) and others, so much sediment travels with the river that it will fill dams, making the dams into lovely, tall waterfalls eventually. That’s not useful for irrigation or supplying urban drinking water.

If you look at a small stream under a large bridge and wonder if the state/county construction people lost their minds, you might be close. They probably pulled a lot of hair out, trying to design a bridge that would stand up to that two-times-a-year flood event, but not cost so much that the state/county screamed. “Why’d they put such a big bridge over that?” is an oft-heard complaint. Come back four or six or fewer hours after a big ‘ol thunderstorm, or a enormous wet low-pressure system dumps rain for a week straight, and you’ll understand why.

I love logging onto the USGS stream gauges for the Canadian and other local rivers and watching floods in real time. the curve goes “flat-flat-bump-liftoff!-crash!”

*shrug* What can I say? I’m a hydrology nerd. I like reading rivers.

10 thoughts on “Flashy River!

  1. I admit that I “ain’t exactly normal” but DAY-YAMN! I shock people with “It;’s NOT COLD, water is *LIQUID*!”

    $HOUSEMATE drove a U-HAUL from SOUTHERN TX and the vehicle ran out of washer fluid – In DECEMBER. That was mentioned. I Picked up a ‘handful’ (hoof-ful) of snow and cleaned the windshield (windscreen to the UK types…) “DAMN! WATER ALL AROUND me and I didn’t realize!”

    A few days later, “WTH is that sound?!?” “Snow. You are driving on snow and it *crunches* under the tires.”

    A couple YEARS later we visit my folks around Christmas in NORTHERN (45 N is SOUTH of us) WI. $HOUSEMATE taps the *DIGITAL* thermometer for it CANNOT be -17 F… it stubbornly refuses to alter indication. $HOUSE drives us all (save Pa?) into town… and INSISTS that I drive back because things are Not Right… Dude… it -17F… grease, oil,m etc. get… *VISCOUS* when it gets Truly Cold.

    And, mind, this was MERELY central WI.

    I had a (ham radio) conversation with a fellow *somewhere* in Alasaka…

    At -20 F.. you just Deal With It,.
    At -40 F you.l. think it over, and if it;s THAT important, you Deal With It.
    At -60 F …. is somebody about to die? NO? IT. CAN. WAIT.

  2. Trying to think of something funny or clever but I need more coffee. 😉

  3. Re: “not from a ‘normal’ part of the world when…” — who gets to say what is normal?

    “I’m a hydrology nerd. I like reading rivers.”

    [shrug] I’m an amateur geologist, so I like reading rocks. There’s worse ways to spend your excess brain cycles…

  4. How about this for a definition of ‘normal’: What’s normal to you plus/minus a certain tolerance.

    And yes, that definition means that different people have different concepts of normality. As long as things (rivers in this case) stick within the expected bounds of ‘normal’ everything is fine. But if things behave ‘abnormally’ then problems might arise. And issues might arise when people move somewhere where ‘normal’ (for where they now are) is ‘abnormal’ (for where their understanding was developed).

  5. Laughing, because I read patterns the same way, including landscape features. Then again, if I’m ever in that part of IL I may place an impromptu sign reading “Standard Deviate” at the correct distance from the town of Normal.

  6. A client of ours who was raised in Laredo repeated to us some of the jokes about the Rio Grande, especially in drought years. After one half-decade long dry spell, the younger catfish had to be taught how to swim. And there were times when it was so dry (how dry was it?) that the catfish had to be sprayed for ticks.
    They used to say pretty much the same thing about the Los Angeles River – that it only had water in it when it rained. Also – fifty feet of bank and five of river…

  7. Ah yes, the ‘joys’ of living in Texas. “You call ‘that’ a river? Ha!” Three months later after a major storm, “OMG, teh floodz! It’s gonna drown us all!” Lather, rinse, repeat…

  8. I live in Arizona, where most of the rivers are dry sandy beds most of the year. Only in certain seasons and after a rain do they have any water in them. Given the urban population of the large cities and the daily traffic that crosses the “rivers” going through them, once or twice a century you NEED those big bridges.

    It was said of my grandfather that he was so stubborn that if he ever got caught in a flash flood, you should start looking for his body upstream.

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