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Denise Reed Pontchartrain Institute University of New Orleans.

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Presentation on theme: "Denise Reed Pontchartrain Institute University of New Orleans."— Presentation transcript:

1 Denise Reed Pontchartrain Institute University of New Orleans

2 Projected Coastal Louisiana Trends: Land Water Land Loss Projected Land Loss Land Gain Projected Land Gain – sq. mi. of coastal landscape lost average rate 35 sq.mi./yr. for 44 years 2000 – 2050 Projected loss - another 513 square miles

3 The Past

4 Land Area Time Natural cycles Rapid land loss Limited land building 20 th century Delta building - River deposition Delta loss - subsidence, storms

5 Existing marshes must build up to survive Natural Subsidence Sea-Level Rise + = Higher relative water levels

6 Can marshes keep pace with subsidence and sea-level rise?

7 Marsh Building Processes DeLaune et al. 1990

8 How do marshes build without sediments from the river? Storms! Increase water levels and mobilize sediment

9 Cahoon et al., 1995

10 Fourchon Date 5/7/96 5/21/96 6/4/96 6/18/96 7/2/96 7/16/96 7/30/968/13/968/27/ Sediment Deposition (g/cm 2 /day) Tide (m above local datum) Hurricane Dolly 22 August 1996

11 Reed et al., 2006 Hurricane Lilli 2002

12 How Much Sediment for Maintenance? Katrina and Rita estimated to have delivered 130 million tonnes (Turner et al., 2006)

13 River levees stop restrict delta building to a few areas Regular sediment supply from the river to existing marshes is eliminated. Storm reworking is their only source of sediment.

14 Houma Navigation Channel MRGO Navigation Channels

15 Pipeline Canals

16 Solutions? Maintain what we have Rebuild what weve lost

17 Continuing Current Management

18 Achieving Sustainability

19 Prevent loss of sediments into the deep Gulf

20 Coast 2050

21 ..large-scale concepts that could provide significant long-term ecosystem restoration benefits

22 Photo taken by NASA April 29, 2008 Average annual loss to Gulf ~120 million tons of sediment

23 21 st Century Sea level rise accelerates…. Storm impacts increase…. Using the River gives Coastal Louisiana a fighting chance


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