Nancy Barber (nlbarber) wrote,
Nancy Barber

Cool hurricane hydrology

From my dry vantage point 4 states away, I stop to point out a very interesting consequence of Hurricane Ike's move onshore in southeast Texas:,00060
On this stream gage in Beaumont, the storm surge is strong enough to reverse the flow in the river. The gage height graph at the top shows the typical water-level rise of a flood, but the bottom graph shows streamflow (discharge) that went negative when the storm hit. Positive values are flow downstream, negative means the river is flowing upstream. (The negative values will show up on the default graph for 7 days, then you can adjust the plotting period to see them for 60 days before they age off.)

Cool. I didn't know our gages could even record that. (OK, I'm a ground-water hydrologist, not a surface-water one, so I never thought about the problem before). Must be the relatively new equipment that measures velocity as well as gage height. The old-fashioned method of stream gaging was/is that you install a continuous monitor for the gage height, and then you go measure the streamflow over the range of gage heights and construct a stage-discharge curve so you can translate any gage height to a streamflow. Well, any height that's in the range of your curve...thus the desire to go measure the stream anytime the river gets higher or lower than you've measured before, and the reason that field technicians go out to try to measure streams at the peak of a flood. But a gage height monitor wouldn't let you know that the river was running backwards.

I note that this is a gage right at the coast, and it shows flows that are just barely negative regularly (tides). Under Ike's influence, it's flowing at quantities well above the daily maximum recorded there, and upstream. However, it looks like the flow has already reversed and that water will all now go the other way--and the daily average may well come out close to zero. I'll be interested to see...
Tags: nwisweb, work

  • Apple Cinnamon Flatbread (KA)

    Breakfast this morning was this Cinnamon-Apple Flatbread, which is both on the King Arthur Flour blog and recipe collection. It was very good…

  • Pi Day!

    Younger niece called to make sure that I was aware that it was Pi Day (I'd let it slip my mind, actually) and to ask what I was doing about it. I…

  • Last night's supper

    Supper last night: smoked turkey chowder and bacon cornbread muffins (baked in a popover pan) Southern style, which started out from this Peter…

  • Post a new comment


    default userpic

    Your reply will be screened

    Your IP address will be recorded 

    When you submit the form an invisible reCAPTCHA check will be performed.
    You must follow the Privacy Policy and Google Terms of use.