Levees, MRGO, Surge Barriers

URS – The Direct Impact of the Mississippi River Gulf Outlet on Hurricane Storm Surge

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This post has materials that explain why the MRGO did not increase the flooding of New Orleans during Hurricane Katrina.

Article – The Hurricane Katrina Levee Breach Litigation: Getting the First Geoengineering Liability Case Right. (alternative source)

URS. The Direct Impact of the Mississippi River Gulf Outlet on Hurricane Storm Surge. Performed under: CONTRACT NO. 2503-05-39, Hydrodynamic Modeling Effort for MRGO Study, Prepared for: State of Louisiana, Department of Natural Resources (February 2006)

The MRGO channel does not contribute significantly to peak surge during severe storms, when the conveyance of surge is dominated by flow across the entire surface of the coastal lakes and marsh. Nor does the channel contribute significantly to wave run-up. p. ES-2

Attachment: Numerical Modeling of Storm Surge Effect of MRGO Closure

All Figures (large file)

Figure 1 Project Area
Figure 2 Corps Estimate of Regional Inundation from Category 4 and Above Storm Surge
Figure 3 LWRRI  Estimate  of  Regional  Inundation  from  Hurricane  Georges  (1998) Prior to Track Turn
Figure 4 Full 2003 ACIRC Grid
Figure 5 Detail of 2003 ADCIRC Grid for MRGO and Surrounding Area
Figure 6 3D Depiction of 2003 ADCIRC Terrain for MRGO and Surrounding Area
Figure 7 Comparison of Surveyed versus 2003 ADCIRC MRGO Channel Near Shell Beach, Plan
Figure 8 Comparison of Surveyed versus 2003 ADCIRC MRGO Channel Near Shell Beach, Cross Section
Figure 9 Tracks for Hurricane Simulations
Figure 10 3D Depiction of 2003 ADCIRC Terrain with Closed MRGO
Figure 11 Maximum WSE for 124-Knot-Fast Storm, Baseline MRGO
Figure 12 Maximum WSE for 124-Knot-Fast Storm, Closed MRGO
Figure 13 Difference  in  Maximum  WSE  for  124-Knot-Fast  Storm,  Baseline  versus Closed MRGO
Figure 14 Storm  Surge  Stage  Hydrographs,  124-Knot-Fast  Storm,  Baseline  versus Closed MRGO
Figure 15 Maximum WSE for Hurricane Betsy, Baseline MRGO
Figure 16 Maximum WSE for Hurricane Betsy, Closed MRGO
Figure 17 Difference in Maximum WSE for Hurricane Betsy, Baseline versus Closed MRGO
Figure 18 Storm Surge Stage Hydrographs, Hurricane Betsy, Baseline versus Closed MRGO
Figure 19 Storm Surge Current Speed Hydrographs, Hurricane Betsy, Baseline versus Closed MRGO
Figure 20 Hurricane Katrina Simulation
Figure 21 Maximum WSE for Hurricane Katrina, Baseline MRGO
Figure 22 Maximum WSE for Hurricane Katrina, Closed MRGO
Figure 23 Difference in Maximum WSE for Hurricane Katrina, Baseline versus Closed MRGO
Figure 24 Storm Surge Hydrographs, Hurricane Katrina, Baseline versus Closed MRGO
Figure 25 Storm Surge Current Speed Hydrographs, Hurricane Katrina, Baseline versus Closed MRGO
Figure 26 Baseline 2003 ADCIRC Levees
Figure 27 Modified Levees
Figure 28 Maximum WSE for Hurricane Katrina, Modified Levees and Closed MRGO
Figure 29 Difference  in  Maximum  WSE  for  Hurricane  Katrina,  Baseline  versus Modified Levees
Figure 30 Storm  Surge  Hydrographs,  Hurricane  Katrina,  Baseline  versus  Modified Levees
Figure 31 Schematic of Wave Set-up and Run-up
Figure 32 HPL Cross Section near Bayou Dupre, Station 673
Figure 33 Lake  Borgne  to  HPL  Levee  @  Bayou  Dupre  Transect  for  Wave  Run-up Analysis
Figure 34 Schematic of Wave Generation and Attenuation for Lake  Borgne to HPL Levee @ Bayou Dupree
Figure 35 3D  Depiction  of  Higher  Resolution  ADCIRC  Terrain  for  MRGO  and Surrounding Area with Closed MRGO