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(warm tone playing)

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- [Narrator] For too long,
researchers have had to rely

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on old data when determining
flood estimation across Texas.

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This project, headed up by

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the Texas Tech Center for
Multidisciplinary Research

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in Transportation was
designed to update the Texas

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generalized skew map
for the Texas Department

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of Transportation Hydraulic Design Manual.

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- The map that we have
in the HDM right now

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was produced in 1996, right?

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And so it was based on older record and

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a smaller record.

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So the greater the record you have,

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the more accuracy you have.

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- [Narrator] Researchers
utilized 30 years of unused data,

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which will likely open the door

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for future statistical research into

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Texas, Oklahoma and Eastern
New Mexico flood hydrology.

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- New technologies have become available

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in the last 15 years.

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And quite a bit of recent
data has become available

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in the flood frequency arena.

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And that's important

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for transportation infrastructure design

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in particular bridges, culverts, roadways

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and associated drainage infrastructure.

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- Those skew values are used
in developing a gauge analysis.

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And so what a gauge analysis is,

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is really just taking a distribution

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and a population of flow rates,

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annual flow rates, peak flow rates,

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and fitting a curve to it.

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And that curve shape is changed

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based on what region you're
in Texas with the skew.

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And so it can trend up.

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It can trend down.

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- The information we used
are stream flow records

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that are stored by the United
States geological survey

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for Texas specific stations

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and included Oklahoma, parts
of New Mexico, Louisiana.

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Also, those skew values
should not abruptly change

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just because you crossed the state line.

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So we need to have the adjacent states

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to help inform our analysis.

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And from that, we create
a probability model

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of the behavior of the flood recurrence

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at particular locations.

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And we found that the
skew values for the state,

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incorporating new data,

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have changed somewhat from
the last time this was done.

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And the impacts of those
modified skew values

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are fairly important
along the coastal bend

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and the coastal plains of Texas,

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somewhat in the hill country

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and less so out here in West Texas.

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- And so if you look at the two maps

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and put them side by side,
there's better resolution too.

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There's less gaps between the contours.

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So there's less averaging
or interpolation.

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So now you're getting better
accuracy with your flow rates.

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So if you're overestimating your flows,

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your bridges will be bigger, right?

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So we're spending more
money on our bridges.

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If you underestimate, that
translates into a safety issue

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or a reliability issue.

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So we want to be as accurate as we can.

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We don't want to overestimate.

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And we don't want to underestimate

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- [Narrator] For more information

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and to find the publications
for this project,

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please visit the text dot research library

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at the link shown below.