1. US Army Corps of Engineers BUILDING STRONG ®

2. Slide 2

3. BUILDING STRONG ® Slide 3 In March of 2012 briefed CPRAB and identified need to follow up on three items: 1. Overtopping rates above the crossover point 2. Armoring MRL above the crossover point 3. LPV 149 Tie-In to MRL

4. BUILDING STRONG ® Slide 4  Along the west bank of the MRL above RM 85.5 (west bank crossover point) and the east bank above 81.5 (Caernarvon tie-in) there are isolated locations that do not meet the MR&T authorized grade or the1% HSDRRS design elevation  USACE concluded that these locations are acceptable for a positive finding for the Levee System Evaluation Report (LSER) based on:  Average overtopping rates along an entire reach  Performance capabilities of established turf  Capabilities of interior drainage

5. BUILDING STRONG ® Slide 5 RM 85.5 West bank crossover point RM 77.5 East bank crossover point

6. BUILDING STRONG ® Slide 6  Armoring is not a requirement for a positive LSER  No authority to armor above the crossover point on the MRL  At the locations that do not meet the 1% design elevation, analysis shows that the overtopping rates for the 500 year event exceed the 0.5 cfs/ft threshold for armoring  Although overtopping rates exceed the armoring threshold, studies at Colorado State show well established turf performs well up to 4 cfs/ft

7. BUILDING STRONG ® Slide 7 Overtopping rates for 500yr event in cfs/ft

8. BUILDING STRONG ® Slide 8  Higher elevation transition tie-in from HSDRRS floodwall to MRL is necessary (from El +21.5 to +24.0 feet)  T-wall and earthen levee tie-in options were investigated – earthen tie-in is recommended plan  Work will extend 100 linear feet up river and 30 linear feet down river along the MRL from the T- Wall  65% Design in Progress  Expect to advertise: August 2013 LPV 149 Typical Section HSDRRS and MRL Earthen Levee Tie-in

9. BUILDING STRONG ® Slide 9

10. BUILDING STRONG ® Slide 10

11. BUILDING STRONG ® Slide 11

12. BUILDING STRONG ® 12 March 2009 Draft “Mississippi River Levees Assessment” complete. Identified need to raise MRL for Hurricane events Januar y 2010 Design Summit - experts invited to review modeling and design of 1% HSDRRS along the river April 2010 Alternatives to raise both east and west bank levees to meet the 1% HSDRRS design grade based on initial modeling completed in March 2009. July 2010 Based on design summit revised analysis for modeling waves and how they form on the river. Completed quality control and agency technical reviews Existing east bank MRL were sufficient Work required on west bank MRL to RM 85.5 March 2011 March 2012 Commitment to complete further analysis on overtopping rates for east and west bank above the crossover points Provide SLFPA-E letter addressing several questions and concerns (April 2012) Completed analysis of overtopping rates No change to work required on MRL for 2011

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15. BUILDING STRONG ® Slide 15 85.5 95.5 77.5 79.5 81.5 70 91 89

16. BUILDING STRONG ® Slide 16 ISAAC EOC Briefing Mississippi River Update West Point a la Hache IHNC Lock Carrollton Baton Rouge 12.4 ft 11.3ft 12.4ft Still Rising….

17. BUILDING STRONG ® Slide 17 Mississippi River Surge Levels from Venice to Red River RM 302 RM 8 West BayPoint a la HacheAlliance CarroltonBonne Carre Baton Rouge Donaldsonville St. Francisville Red River Landing