US Army Corps of Engineers BUILDING STRONG ® Repairing the Mississippi River Levee with Dredged Material after the Historic 2011 Flood Dredging 2012 Shane.

US Army Corps of EngineersBUILDING STRONG®

Repairing the Mississippi River Levee with Dredged Material after the Historic 2011 Flood

Dredging 2012

Shane Callahan, P.E.

Michael Clay, P.E.Memphis DistrictOctober 24, 2012

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Birds Point – New Madrid Floodway

• 33 miles long• 10 miles wide• 205 sq. mi.

Inflow # 1

Inflow/Outflow # 1

Inflow/Outflow # 2

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Fuse Plug Levee

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Birds Point – New Madrid Floodway

Constructed in 1928 in response to the flooding experienced in 1927.

Activated only once before 2011 – 1937

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0

62.5 – Project Design Flood EL. 333.0

EL. 270.5

60.0 – 100 Yr Event

58.5 – 50 Yr Event329.0

330.5

56.0 – 25 Yr Event326.5

52.3 – 10 Yr Event322.8

49.3 – 5 Yr Event319.8

Flood of Record1937 – 59.5’

1997 – 56.2’ > 1973 (55.7)

2008 – 53.9’

Cairo Gage

2002 – 55.0’

2005 – 53.2’

2011 Flood61.72’

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Floodway Activation

Video of Detonation:► http://www.youtube.com/watch?v=RfIII1Fovqc&feature=relmfu

Video of Flow filling Floodway► http://www.youtube.com/watch?v=Xz3LIeBhkYs

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Less Powerful Blasting Agent

Lack of Broad overflow

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Concentrated Flow

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Scour Hole Formation 12.5 acre, 50’

deep scour hole

Over 450,000 CY of displaced material

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Floodway Activation

Side by side comparison of aerial photography before activation and soon/directly after activation

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Repairing the Levee

Sand and sediment surrounding the area were pushed into scour hole – too slow

A faster approach to filling the scour hole was required

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Dredging Proposed

Dredge Iowa►Hull length = 194 ft►Hull width = 32►Ladder = 76 ft►Cutter Brake H.P. =

300 HP Average Dredge

Fill Rate: 20,000 CY/day

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Environmental Complication

Protect Fill

Separate

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Environmental Complication Blue Hole contamination Original containment proposal involved

a rock/rip-rap dike►$2 million +►3 months or more►Potentially ineffective sediment

containment system

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Environmental Solution

Sediment Curtain►2 week lead time►3 day installation time►Approx. $50,000►Virtually impenetrable to sedimentBlue Hole Scour Hole

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Sediment Curtain Install

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Begin Dredged Fill

Dredge

Blue Hole

Dredged Fill

Area to be Filled

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Begin Dredged FillBlue Hole

Dredged Fill

Area to be Filled

Incoming Slurry Pumped

Drain

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Dredged Fill

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?QUESTIONS?