Failure of Levees Due to Hurricane Katrina and Future of Hurricane Protection Systems in New Orleans

1
Failure of Levees Due to Hurricane Katrina and
Future of Hurricane Protection Systems in New
Orleans

• Andrew J. Whittle
• Massachusetts Institute of Technology
• September 2006

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Outline

• Background
• History of flood protection in New Orleans
• Was there ever a Hurricane Protection System?
• Hurricane Katrina
• Observations
• Premature failures of levees - some causes
• Future
• Designing a Hurricane Protection System

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Mississippi River Drainage Basin

• Drains 41 of continental U.S. 1.2M sq. miles
• Includes 31 states 2 provinces

Importance of Port of New Orleans Historic
concerns River flood control navigation
Source USGS
4
Dynamic Geological EnvironmentMigratory Nature
of Delta Lobes
1954-1963Old River Control Structure Restricts
flow into Atchafalaya River
5
Elevation Map of New Orleans
Lake Pontchartrain
Lake Borgne
Shows very clearly the natural levee around the
Mississippi River Elevations of Lake
Pontchartrain controlled by tides in Gulf of
Mexico
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History of Flood Protection Drainage
Mississippi Flood 1927 Rising Tide J.M. Barry,
1998
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New Orleans Parishes Drainage Basins
8
Lower Mississippi Industrial Facilities
9
Offshore Louisiana
25 of US natural gas production 17 of US oil
production 30 of US coastal fisheries
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Previous Hurricane Inundation
Two major hurricanes affecting New Orleans
(pre-Katrina) Betsy, 1965 Camille, 1969
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Authorized HPS 1965 - 1978
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1970s Proposed Closure of Lake Pontchartrain
Lake Pontchartrain
Lake Borgne
MRGO (1960s)
USACE appropriated funds (no Environmental Impact
considerations) Scheme abandoned when
environmental law suits were filed
13
Historical Observations of Land Loss
Source USGS, National Wetlands Research Center
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The Challenge of Flood Protection
0 40 miles
Loss of coastal land direct erosion, chanelling
of river-born sediment, subsidence
Source Dartmouth Flood Control Center
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Path of Hurricane Katrina
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Performance of Hurricane Protection System

• Assessment Teams
• Collect perishable data, characterize damage
• Three Teams NSF, ASCE, LSU
• NSF Assessment Report
• IPET - US Army Corps of Engineers
• Provide credible objective scientific and
  engineering answers to fundamental questions
  regarding performance of hurricane protection
  system
• 10 Teams (USACE outside specialists)
• Draft Final Report - June 2006
• https//ipet.wes.army.mil
• Review Teams
• ASCE
• NRC/NAE (includes Whittle Bras)
• Independent Research (ILET)
• NSF Geotechnical Team (UC Berkeley)

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Simulation of Katrina Storm Surge(IPET, 2006)
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Existing New Orleans Area Hurricane Protection
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Hurricane Protection System - As Authorized 1992
System built to these elevations Settlement
subsidence caused 2-3ft reduction in crest
elevations
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Flood Protection Levees New Orelans
Levee elevations - designed for Standard Project
Hurricane (SPH) storm surge
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The Hurricane Protection SystemPrimary Components
I-Wall
T-Wall
Levee
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Flood Walls for IHNC Drainage Canals
Walls added after 1990
Source Rogers
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The System Was Incomplete
45 completed in 2005 Completion not anticipated
until 2018
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Breaching of Levee System Hurricane Katrina
Breaches in 17th Street, London Ave. Canals and
Inner Harbor Navigation Canal account for almost
70 of flooding (IPET, June 2006)
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Overtopping During StormRoute 47 bridge
(MRGO/GICW)
Source Assessment Report, Nov. 2005
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Levee After Storm Route 47 bridge (MRGO/GICW)
Source Assessment Report, Nov. 2005
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Scour of Levees MRGO - Bayou Bienvenue to Bayou
Dupree
Source Assessment Report, Nov. 2005
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Scour I-wall Failure MRGO at Bayou Dupree
Source Assessment Report, Nov. 2005
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Breach at IHNC
Photo AP Press
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Breach at IHNC
31
INHC Breach - Temporary Repair
Source Assessment Report
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Breach at IHNC - Detail
Source IPET
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Breach at 17th Street Canal
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17th St. Canal - Temporary Closure
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London Ave. Breach NorthFilmore West wall near
Robert E. Lee Bridge
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London Ave. Breach NorthWest and East Walls
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London Ave. North - Temporary Repair
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New Orleans Maximum Flood Depth Map
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Flooding within New Orleans Metro Area
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De-watering New Orleans53 days 250 Billion
Gallons
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Levee Damage Map - Final169 of 284 miles of
levees damaged (41 miles severe damage)34 of 71
pump stations - damaged
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Damage Assessment - Orleans Parish
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London Ave (North) - Before After
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London Avenue South Breach Site
Source IPET, May 2006
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Location of Pine Island Beach Ridge
Source IPET, March 2006
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Geological Cross-Section (West-East)
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Initial Section London Ave. South Breach
Source IPET, May 2006
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London Ave. South Steady Seepage
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London Ave (South) - Stability
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Stage Hydrograph - 17th Street Canal
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Site Investigation 17th St. Breach
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17th Street Slide Block
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17th St. Canal Levee Centerline Section
54
CPT and Soil Borings
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IHNC Undrained Strength Profiles
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Failure of 17th St. Canal (from ILET)
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Failure of 17th St. Canal (from ILET)
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Physical Model Tests

• Geotechnical centrifuge
• RPI US Army Corps, Vicksburg
• Used peat from site
• First results released - March 2006

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RPI Test on 17th St. Canal Model
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Re-Construction Work

• USACE Task Force Guardian
• Repair hurricane damaged components by June 1,
  2006
• Restore undamaged levees / floodwalls to
  originally authorized heights by September 1,
  2007
• Complete constructed portions of authorized
  projects by September 2007
• Higher Levels of Protection
• South Louisiana Hurricane Protection and
  Restoration Report preliminary report due June
  2006, final December 2007

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Southeast Louisiana HPS Improvements
Selective Armoring

• Levees and floodwalls will be armored at
  critical points to resist damage from overtopping
• Transitions points between levees, floodwalls,
  and other structures will also be armored

Source Link, April 2006
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Erosion at Soil-Water Interface
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Erodability of Soils
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Floodgates - Temporary Closure
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Southeast Louisiana HPS Improvements
Outfall Canal Closures

• Three locations on Lake Ponchartrain
• Provide New Orleans with rainwater and
  overtopping drainage
• Prevent storm surge into canals
• Removes 14 miles of floodwalls from primary HPS

Source Link, April 2006
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Category 5 Protection System?
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Southeast Louisiana HPS Improvements
Navigable Flood Gates

• Two Locations
• Seabrook
• GICW/MRGO
• Prevents storm surge from Industrial Harbor area
• Removes 20 miles of levees and floodwalls from
  primary HPS

Source Link, April 2006
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Lines of Defense
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Southeast Louisiana HPS ImprovementsEcosystem
Restoration
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Subsidence Satellite Data 2002-2005 mm/yr
Source Dixon et al., Nature, 2006