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View Diary: Drought and Low Water: The Mississippi May Be Unnavigable Within Weeks (191 comments)

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  •  But the point is it's not swings (18+ / 0-)

    Drought actually causes flooding.  It's not swingy at all for droughts to be followed by floods.  When the land gets dry it also gets less "spongy" and can no longer soak up water when the rain does come.  So you don't need a wide swing of no rain followed by too much rain to get floods.  You just need no rain followed by rather moderate rain.

    •  long-term plans-what about more small reservoirs? (6+ / 0-)

      would be an upside to the floods and balance out the droughts.

      •  Absolutely (13+ / 0-)

        One of the things that is little commented on in the discussions about climate change is the loss of water catchments.  

        If we are going to transition to a warmer planet without ice caps, without glaciers, with much reduced winter snow cover, that makes for a lot less water when you want to go turn on the hose.  And as the previous post noted, when rain does come and in deluge form, it doesn't soak in and tends to run off. In the future, catchments will be needed to hold surface waters and recharge underground aquifers.  If we weren't so worried about fiscal cliffs, there could be a lot of civil engineering projects (and jobs!) being done.

        Another thing to think about is how our agriculture is dependent on shallow rooted annual plants that are not very drought tolerant.  All of the cereal grains are grasses that do best with regular watering.  The most drought tolerant one, millet, is also the one with the least research attention devoted to it.

    •  we went the other way, sir. (0+ / 0-)

      An ambulance can only go so fast - Neil Young

      by mightymouse on Mon Nov 26, 2012 at 05:47:16 AM PST

      [ Parent ]

    •  This comment makes no sense (2+ / 0-)
      Recommended by:
      nchristine, LilithGardener

      1. The Mississippi went from historic flood in 2011 to very low this year. This is indeed a wide swing!

      2. Your comment talks about going from drought to flood. But we went from flood to drought. I don't get the relevance of your argument.

      Again, in the past 18 months the Mississippi has gone through an extreme swing in flow - from historic Max in early 2011 to historic low this fall.

      This is remarkable, no?

      From wikipedia on the 2011 flood:

      The Flood of 2011 set new record stages at Vicksburg and Natchez. [30] [31] The peak streamflow at Vicksburg, 2,310,000 cubic feet per second (65,000 m3/s), exceeded the both the estimated peak streamflow of the Great Mississippi Flood of 1927, 2,278,000 cu ft/s (64,500 m3/s), and the measured peak streamflow of the 1937 flood, 2,080,000 cu ft/s (59,000 m3/s).

      An ambulance can only go so fast - Neil Young

      by mightymouse on Mon Nov 26, 2012 at 08:02:59 AM PST

      [ Parent ]

      •  Actually, it does make sense (4+ / 0-)

        The commenter's point is simply that the same rain that would cause no flood at all in a normally wet year can cause extensive flooding if it follows an extended period of drought.

        This is because the dried-out ground is less capable of absorbing water quickly than it would be if it held a normal amount of moisture. It's the same effect you get if you put a completely dry bath sponge (the old-fashioned hard kind) in a bowl of water. It can take a minute or two for the sponge to become completely saturated with water, but if you then wring it out and put it back in the bowl, it will absorb the same amount of water in a couple of seconds. Dry soil works in pretty much the same way.

        So, less absorption into the soil means more runoff, which means larger flows in rivers and streams. And there's your flood.

        "A government that robs Peter to pay Paul can always depend on the support of Paul." - George Bernard Shaw

        by Drobin on Mon Nov 26, 2012 at 09:38:09 AM PST

        [ Parent ]

        •  it's a non-sequitur (1+ / 0-)
          Recommended by:
          LilithGardener

          We are not in a situation where heavy rain followed drought. We are in the opposite situation.

          Last year the Mississippi had record high flow. This year it's record low flow.

          From one extreme to the other in 18 months. We are certainly visiting the extremes these days, yes?

          Of course I understand the point, but it's not relevant, and I wonder why the poster felt compelled to add it.

          People do that kind of thing when they want to change the subject.

          An ambulance can only go so fast - Neil Young

          by mightymouse on Mon Nov 26, 2012 at 09:44:54 AM PST

          [ Parent ]

          •  He was making a general comment (2+ / 0-)
            Recommended by:
            billlaurelMD, Aquarius40

            which may or may not have been applicable to the flood last year (someone better versed in hydrology would have to comment on that point).

            The point is that rather counterintuitively, frequent flooding is a feature of a drier climate. Since climate change deniers are likely to point to floods as evidence that the climate is not actually getting drier, I think it is important to point out that there is no contradication there.

            "A government that robs Peter to pay Paul can always depend on the support of Paul." - George Bernard Shaw

            by Drobin on Mon Nov 26, 2012 at 09:57:19 AM PST

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            •  drought and flood can both happen (0+ / 0-)

              Not sure who is expecting less flooding in the warming climate - that has a strawmannish feel.

              We get more heavy rain now. Naturally we get more flooding.

              Also, with warmer air and more blocking patterns, we can get more drought.

              The two extremes can co-exist w/o casting doubt on global warming.

              An ambulance can only go so fast - Neil Young

              by mightymouse on Mon Nov 26, 2012 at 10:24:29 AM PST

              [ Parent ]

      •  It's a strawman to cite river levels (0+ / 0-)

        since I never claimed there was no flooding and no drought.  I claimed that a big swing between low rain and high rain is needed to cause that.  Swings between low rain and normal rain are enough.

        •  garr... NOT needed. (0+ / 0-)

          that'll teach me to not proofread:
          This sentence:

          I claimed that a big swing between low rain and high rain is needed to cause that.
          Should have been this:
          I claimed that a big swing between low rain and high rain is not needed to cause that.
        •  We didn't go from dry to wet (0+ / 0-)

          We went from wet to dry.

          Your comment is a non-sequitur. Why did you put it there?

          Do you agree that we've seen what must be a record or near-record swing in Mississippi flow over the past 18 months? Do you find this notable?

          An ambulance can only go so fast - Neil Young

          by mightymouse on Mon Nov 26, 2012 at 10:59:15 AM PST

          [ Parent ]

          •  I don't disagree with your re-written claim (0+ / 0-)

            that it was a swing in the river level.  The claim I was disputing was the claim it was a massive swing in the weather.  Weather != river level.

            •  but there WAS a massive swing in the weather (1+ / 0-)
              Recommended by:
              LilithGardener

              what made the river flood in 2011?

              wikipedia:

              In April 2011, two major storm systems deposited record levels of rainfall on the Mississippi River watershed. When that additional water combined with the springtime snowmelt, the river and many of its tributaries began to swell to record levels by the beginning of May
              It rained for days in places like KY.

              In 2012 - record drought!

              I don't understand why you are so insistent that it was not wide swings in the weather that drove the extreme swing in river flow.

              Your point may be true but it does not seem relevant to this case. So still I don't know why you brought it up.

              And it's not just a "swing" in river level - it's a record swing.

              An ambulance can only go so fast - Neil Young

              by mightymouse on Mon Nov 26, 2012 at 02:03:03 PM PST

              [ Parent ]

          •  The 2011 flood (2+ / 0-)
            Recommended by:
            mightymouse, LilithGardener

            as I recall, was caused, at least in part, by very heavy snowfall and early spring rain in the upper Missouri basin. There was not enough capacity in the Missouri river dams to hold the excess water.

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