1000 Year Flood Event

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SUPERFLOOD!

• 1000 Year Flood Event
• Terry D. Leatherwood, P.E.

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May 1-2, 2010

• On the above dates, a massive rainstorm swept
  through West and Middle Tennessee.
• The storm crossed the Mississippi River, North of
  Memphis, and swept Northeast toward Nashville.
• Many areas received from 15 to 20 inches of rain
  during a 48 hour period.

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Affected Area
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Heavy Flooding Occurred
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Statistics

• 21 Deaths occurred in Tennessee due to the flood.
• 52 of Tennessees 95 Counties were declared as
  Federal Disaster Areas.
• Although a final tally has yet to be made,
  damages in Tennessee are expected to be over 2
  billion dollars.

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Singing the Blues!
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Unusual Damage
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Unusual Damage
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Unusual Damage
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What about the Highway Bridges?

• 44 of the 52 Counties had bridges that suffered
  maintenance issues because of the flood. The
  total currently stands at 1,167 structures with
  damage.
• These 44 Counties have a total of 10,216 highway
  bridges over waterways.
• Therefore, only 11.4 of bridges over waterways
  needed maintenance. 88.6 of the highway bridges
  survived the flood with NO SIGNIFICANT DAMAGE.

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BridgeWatch System
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Tracking the Damage

• In order to track the damage, a database table
  for flood damaged bridges was created.
• Five categories of damage were tracked.
• Bridges could have multiple types of damage.
• If the bridge required closure, that was also
  noted.

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Debris Accumulation
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Debris Accumulation
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Debris Accumulation
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Approach Roadway Damage
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Approach Roadway Damage
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Approach Roadway Damage
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Approach Roadway Damage
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Approach Roadway Damage
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Embankment Erosion
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Embankment Erosion
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Embankment Erosion
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Embankment Erosion
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Bridge Scour
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Bridge Scour
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Bridge Scour
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Structural Damage
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Structural Damage
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Structural Damage
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Structural Damage
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Structural Damage
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Summary of Flood Damage

• Our Database shows damage to 1,167 Highway
  Bridges
• 773 Bridges had a single type of damage
• 317 Bridges had two types of damage
• 65 Bridges had three types of damage
• 4 Bridges had four types of damage
• 1 Bridge has all five types of damage

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Summary (Continued)

• 504 Bridges showed debris accumulation
• 415 Bridges had damage to the roadway approaches
• At 362 Bridge Sites, there was channel embankment
  erosion
• 225 Bridges showed scour damage
• 115 Bridges suffered some type of structural
  damage
• 54 Bridges required closure

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Questions?