US Army Corps of Engineers BUILDING STRONG ® Louisiana Coastal Area Modification of Davis Pond Study Overview Governor’s Advisory Commission on Coastal Protection, Restoration and Conservation Mark R. Wingate, PE Chief – Projects and Restorations Branch April 4, 2012

BUILDING STRONG ® Purpose  To update the Governor’s Advisory Commission on progress of the LCA Modification of Davis Pond feasibility study: ► Planning Objectives and Constraints ► Alternatives under consideration ► Other factors to be considered ► Timeline to completion 2

BUILDING STRONG ® Background One of 15 critical projects authorized in WRDA 2007 “to sustain a larger coastal ecosystem that supports and protects the environment, economy, and culture of southern Louisiana” WRDA language provided sequencing insight Modification of Davis Pond (MDP) - Title VII, Sect 7006(e) – LCA “4” LCA “4” FCSA Signed 5 June 2009 (includes MDP) Next Step – TSP selection (13 April 2012) Chief’s Report to be signed - 1 Nov

BUILDING STRONG ® Planning Goals and Objectives Goal: Identify operational change that maximizes restoration outputs in the Barataria Basin Objectives: Over the 50 yr period of analysis: Objective 1: Decrease the rate of land loss, and where possible, increase wetland acreage Objective 2: Increase the geographic extent and distribution of Davis Pond freshwater, sediment, and nutrients throughout the study area 4

BUILDING STRONG ® Planning Constraints Avoid or minimize negative impacts to T&E (Pallid Sturgeon) Avoid or minimize adverse impacts to habitat Maintain level of flood protection/no induced flooding Avoid or minimize impacts to navigation Avoid or minimize low dissolved oxygen and/or algal blooms Assess only operational changes Other factors to be considered 5

BUILDING STRONG ® Analytical Tools 1)H&H Modeling (TABS) – detailed history and forecast of hydrology 2)SAND Model - estimates sediment deposition rates 3)WVA - estimates restoration outputs 4)IWR - economic analysis on cost effectiveness 5)Trade-off Analysis - Socioeconomic Impacts, EFH 6

BUILDING STRONG ® Modeled Area GRAND ISLE DIVERSION STRUCTURE MYRTLE GROVE 7

BUILDING STRONG ® Alternatives Under Consideration 8

BUILDING STRONG ® Plan Formulation Developed an initial array of 42 alternatives Screened based on criteria Final Array ► 8 alternatives ranging from “no-action” to operating at maximum capacity throughout year 9

BUILDING STRONG ® Future Without Project: No Action -Maintain current operation of structure X X MYRTLE GROVE 10

BUILDING STRONG ® River Stage Dependent/Open Continuous: Alternative 18 -Maximum possible flow throughout year -No Salinity target -No Time constraints X X X X MYRTLE GROVE 11

BUILDING STRONG ® Maximize Sediment Load and Maximize Footprint: Alternative 41 -Maximum capacity operation during sediment peaks -Establish new salinity target during non-sediment peaks X X MYRTLE GROVE 12

BUILDING STRONG ® Major Flow Event (3 Year Cycle): Alternative 17 -Capture maximum sediment for year 1 during sediment peaks -For years 2 and 3, focus on establishing new salinity target -Repeat 3 year cycle X X MYRTLE GROVE 13

BUILDING STRONG ® Major Flow Event (5 Year Cycle): Alternative 40 -Capture maximum sediment from the river for year 1 during sediment peaks -For years 2, 3, 4, and 5, focus on establishing new salinity target -Repeat 5 year cycle X X MYRTLE GROVE 14

BUILDING STRONG ® Maximize Sediment Load With Time Constraint (Jan – Apr): Alternative 42a -Maximize flow during high river conditions -Establish new salinity target for remainder of year X X MYRTLE GROVE 15

BUILDING STRONG ® Maximize Sediment Load With Time Constraint (Jan-Apr): Alternative 42b -Maximize flow during high river conditions -Maintain existing salinity target for remainder of year X X MYRTLE GROVE 16

BUILDING STRONG ® Maintain New 5ppt Isohaline: Alternative 39 -Establish new annual salinity target X X MYRTLE GROVE 17

BUILDING STRONG ® Projected Wetlands in Acres No Action: 45% reduction in landmass over 50 years Alt 18: 43% reduction in landmass over 50 years Approximately 10 square miles difference between Alt 18 and No Action Only assesses operational changes of DP structure *Values Assume Intermediate Sea-Level Rise 18 Project Year No ActionAlt 18Alt 41Alt 17Alt 40Alt 42aAlt 39Alt 42b 0394, ,575360,576360, , ,967324,916325,008324,876324, ,855323, ,268286,562286,563286,336286,302286,277286,246284, ,871255,742255,626255,298255,229255,162255,102252, ,735225,074224,855224,424224,329224,239224,153220,873 Approximate Acres Lost 175,800169,600169,900170,100170,200170,300170,400173,700

BUILDING STRONG ® Wetland Value Assessment Results (Year 50) - AAHU (Average Annual Habitat Unit) – Increased Habitat Quality Alt Habitat (AAHUs) Total Acres Remaining in Basin (50 years) SwampFreshIntermediateBrackishSaline TOTAL INCREASE (AAHU) 1803,4182, ,016225, ,4082, ,658224, ,3002, ,912224, ,2891, ,342224,329 42a03,2161, ,745224, , ,295224,153 42b02, ,106220,873 No Action 218,735 19

BUILDING STRONG ® Other Factors to be Considered  Planning Aid Letter  Environmental effects (adverse and beneficial)  Social effects (adverse and beneficial)  Risks and uncertainties 20

BUILDING STRONG ® Milestone Schedule ActivityFinish Tentatively Selected Plan13 Apr 12 Agency Technical Review (ATR)14 Jun 12 Respond to ATR Comments28 Jun 12 Vertical Team Review12 Sep 12 Alternative Formulation Briefing (AFB)17 Sep 12 Public & Independent External Peer Review15 Feb 13 Mississippi River Commission Prep/Briefing6 Mar 13 Civil Works Review Board3 Jun 13 Final S&A/NEPA Review/Comment Response18 Sep 13 Sign Chief’s Report1 Nov 13 21

BUILDING STRONG ® Questions? 22

BUILDING STRONG ® Backup Slides 23

BUILDING STRONG ® Alt 42b Alt 39 Alt 42a Alt 40 Alt 17 Alt 41 Alt 18 IWR Analysis In thousands

BUILDING STRONG ® Final Array of 8 Alternatives a3942bNo Action Existing 5ppt xx x x New 5 ppt x x x Time Constraint xx xx Sediment Constraint x x x 25