Introduction

1. Introduction Introduction Background Solutions: Environmental and Engineering Intermission Solutions: Social and Political Conclusion

2. Background Introduction Background Solutions: Environmental and Engineering Intermission Solutions: Social and Political Conclusion Geography of New Orleans Hurricane Katrina Environmental Issues Alternative Plans 100 Year Plan

3. New Orleans Geography • Lake Pontchartrain (north) • Lake Borgne (east) • Mississippi River (through the city) • Gulf of Mexico (south) • Wetlands (southeast)

4. Environmental Concerns • Elevation– from 2 m above to 5 m below sea level • Mississippi River bed is rising • Subsidence– 5-8 mm per year • Reduction of Wetlands– 75 sq. km per year • Sea Level Rise– 11 cm to 77 cm in 100 years • Global Warming

5. Hurricane Katrina • Made landfall as a Category 3 in southeastern Louisiana • Sustained winds of 125 mph • Projected storm surge of 28 ft • On August 28th, Mayor Ray Nagin enacted the first mandatory evacuation plan • Superdome housed 26,000 people • Storm surge caused several levee breaches and flooded city • Overall death toll: 1,800

6. Government Response • Response was slow and inefficient • FEMA mobilized 1000 Homeland Security workers • Firefighters and ambulance crews not allowed in immediately • Federal government lacked sufficient devastation information • Problems with looting • Superdome became a humanitarian crisis • Search and rescue efforts were uncoordinated

7. Increasing Hurricane Intensity • Hurricane Betsy - 1965 • 81 casualties • $1.4 billion • Hurricane Camille - 1969 • 335 casualties • $11 billion • Hurricanes Katrina and Rita - 2005 • 2,000 casualties • $105 billion

8. Looking 100 Years Into The Future The Possibilities & The Final Proposal

9. The Possibilities • Rebuild and Improve • Abandon • North Shore Plan • The Final Proposal

10. Rebuild and Improve • Rebuild better than pre-Katrina • High cost • High risk • Preserves unique New Orleans culture • Maintains economy

11. Abandon • Deemed too risky to live in • Organized relocation of citizens • Low cost • Low risk

12. The North Shore • Preserve unique portions • Historical • Economic functions • Relocate residents to St. Tammany Parish • Make New Orleans a commuter city • High risk on North Shore also • Lack of available land

13. The Final Proposal • Downsize to historical sector • Move major port functions • Port of South Louisiana • Baton Rouge • New hurricane and flood protection system • Citizens’ Relocation Committee (CRC) • Use river to develop wetlands

14. The Final Proposal • Incorporates the best from the other possibilities • Preserves historical sector • Provides for relocation of port economy • CRC provides for safety of suburban residents • Smaller region to protect • Lower long-term cost • Lower risk

15. Solutions: Environmental and Engineering Introduction Background Solutions: Environmental and Engineering Intermission Solutions: Social and Political Conclusion Sea Level Rise Wetlands Rivers Flood Protection System

16. Global Warming • Increase in temperature • Caused by emission of greenhouse gases • Affect on sea level rise: • Thermal Expansion • Melting glaciers, ice caps • Changes to hydraulic cycle

17. Sea Level Rise • Range: 10 cm to 100 cm (IPCC Third Assessment Report) • Median: 48 cm • Models used: CCCma, GFDL, Hadley-CM3, MPI

18. Uncertainty of Sea Level Rise • Do not capture multiple climate effects • Uncertainty in heat uptake by deep ocean • Timescales lead to inaction in policy • Kyoto Protocol

19. Subsidence • Types of: • Endogenic – caused by human activities • Exogenic – caused by natural processes • Causes: • Groundwater withdrawal • Petroleum extraction • Tectonic motion

20. Cost of Sea Level Rise • $20 - 150 billion if sea levels rise 100 cm (Pugh, 2004) • $370 million dry land damages • $893 million for wetlands damage • $200 - 475 billion for coastal stabilization • $57 - 174 million in transient costs • 1500 damaged homes yearly (McCarthy, 2001)

21. Louisiana’s Wetlands: Functions • Commercial importance • Produces 1/4 of the nation's oil and natural gas • Produces 1/3 of the nation’s fisheries’ landings • Hosts 2nd largest wildlife habitat in the U.S. • Protective importance • Protection against storm surges • Every 3-4 linear miles of healthy wetlands reduces storm surge by 1 foot

22. Long Term • Reduce and compensate for current rate of loss of 75 square kilometers per year • Prepare for sea level rise • Maintain barrier islands • Improve knowledge of ecosystem dynamics and restoration technology

23. Wetlands Problems and Solutions • Draining and Filling • Zoning laws • Canals and Channels • Use fewer canals • Prevent further erosion from canals • Erosion • Barrier Islands • Use of dredged sediments • Revegetation • River diversions

24. Draining and Filling • Proposed Legislation: • Prohibit draining and filling of ecologically important wetlands • 100 foot buffer between wetlands and developed areas • Best management techniques for drilling and farming

25. Canals • Small Scale Canal Impact • Canal dredging • Human-altered hydrology and substrate collapse • Large Scale Canal Impact • Deep navigation canals • Pipelines • 8,000 miles of pipelines across coastal Louisiana

26. Barrier Islands • Katrina’s destruction of Chandeleur barrier islands (approximately 50% loss) • Present-day: slow rate of recovery • Immediately: dredging • Sand deposits of previous delta lobes (i.e. Ship Shoal)

27. Dredged Sediments-Marsh • Sediment pumped into or placed on shallow water areas • Increases elevation of marshes or creates new marsh • Mixed success • May become more important in the context of increased sea level

28. Revegetation • Major plant death • Salt water intrusion • Lack of nutrients • Stabilization of soil • Species must be well-adapted to predicted conditions • Spartina can tolerate moderate salinity

29. River Distributaries • Dredged sediments and revegetation are inefficient to continue long term • Sediment and nutrient delivery system • Raise elevation • Counteract subsidence • Revive ecosystems to reduce erosion

30. Distributaries • Two distributaries • Each divert up to 1/5 of normal river discharge • Floodgate at entry point to control water level • Open wider during floods • Open less during low water • Armored banks

31. Distributaries • EAST: Breton Sound • Fill in MRGO until Violet Canal • Violet Canal and MRGO form distributary • WEST: Barataria Bay • Wilkinson Canal forms distributary • Establish Barataria Waterway as main canal for Lafayette oil and gas field

32. Cutoff • Southern cutoff • 2 crevasses between cutoff and Buras – maintain navigation, not flood control • No levees below Buras – navigation channel will not be maintained

33. Entry Point: Buras • Buras to replace Head of Passes as main entry point to deep draft channel • Two navigation canals will allow entry from east and west • Bird-foot delta abandoned; nothing south of Buras unless built on a deepwater platform

34. Problem: Riverbed Rise • Riverbed rise • Sediment builds up on riverbed because it cannot be distributed on floodplain • Increasing stress on Old River Control Structure • Maintains 70% discharge through current Mississippi River channel

35. Dredging • River currently being dredged to maintain navigation channel • Very costly but feasible because of economic importance of river

36. Wing Dams • Wing dams: dikes that extend from a river’s banks while allowing water to flow unhindered through the middle of the channel • Water behind dams will slow and drop sediment, building up sediment behind the dam • River channel will narrow and deepen

37. Wing Dams, cont. • Increased current velocity and pressure on bed will increase erosion, promote self-scouring process to bring bed level closer to sea level • River banks must be armored, so that increased erosion occurs on the bottom and not the sides • New river entry point at Buras shortens horizontal distance, allowing erosion to steepen profile

38. New River Specifications • Below Baton Rouge maintain 500 ft wide main channel, wide enough to accommodate riverboat traffic • Between Port of South Louisiana and Wilkinson Canal maintain 650 ft wide main channel, to accommodate the traffic at Port of New Orleans, especially boats turning around

39. Old River • Erosion of bed closer to sea level will decrease height difference between Atchafalaya and Mississippi beds at Old River, currently 12-14 ft • Material will be dredged from behind Old River to match changing elevation of Mississippi River bed • Increases capacity and use of existing structure for flood control

40. Flood Protection System Plans • Filling in the Mississippi River Gulf Outlet • Floodgates and double pumps on the 17th Street, Orleans Avenue, and London Avenue Canal Levees • Levee Reconstruction • Monitoring and Maintenance

41. Filling-In the Mississippi River Gulf Outlet • Storm surge coming up outlet was intensified, causing levees to be breached • Filling-in protects against funnel effect • Commercial/industrial impact

42. Floodgates and Double Pumps • Floodgates stop water from coming into the city through the canals • Gates close when storm surge threatens • Governance by NOAA • Increase and redesign pump system throughout city

43. Levee and Floodwall Reconstruction • Patchwork system • Levees poorly monitored • Subsidence • I-walls protecting Lower Ninth Ward • New Orleans East levees overtopped and eroded • I-walls were not able to handle pressure from storm surges • Scouring and seepage caused some I-walls to fail • Foundations were poor

44. Solutions • Rebuild to withstand Category 5 hurricane: • Replace I-walls with T-walls • Selective levee armoring • Rolled clay levees • Replace poor foundations with compacted soil • New levees from Intracoastal Waterway to Jefferson West Levee System

45. Monitoring and Maintenance • Levee Governance Board • Yearly levee inventory • Differential Global Positioning System to monitor subsidence • Role of Army Corps

46. Timeline Floodwalls and levees raised to approved heights and engineering errors fixed. Nov 2006 2010 Sept 2007 Temporary floodgates on canals. 220 miles of levee repaired. Flood Protection System complete.

47. Intermission Introduction Background Solutions: Environmental and Engineering Intermission Solutions: Social and Political Conclusion

48. Absorbing the Information • The 100 Year Plan • Environmental and Engineering Issues • Sea level rise and subsidence • Wetlands • Mississippi River • Flood Protection System

49. Solutions: Social and Political Introduction Background Solutions: Environmental and Engineering Intermission Solutions: Social and Political Conclusion Downsizing/Zoning Ports/Jobs/Relocation Social/Cultural Insurance/Building Codes Evacuation Costs Committee for Continued Monitoring

50. Downsizing By District What Do We Do Now? • Risk of subsidence, sea level rise, increased storm surge • Returned population- 190,000; 43% of the 2004 population of 440,000 • Residents rebuilding • Repair Hurricane Protection Systems- $300 million spent by Army Corps of Engineers