Unchain the River and Allow it to Build a Delta

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1 Unchain the River and Allow it to Build a Delta Harley S. Winer Atkins Harley.Winer@atkinsglobal.com

2 Mississippi River Drainage Basin Basin Facts Drains 41% of continental U.S. Includes 31 states & 2 Canadian provinces Total area drained around 1.7 million square miles

4 Objectives Land Loss in Coastal Louisiana. Historical Rates and Projected Future Losses Causes Natural and Induced A Viable Solution.

5 Coastal Loss Loss rate in 70 s and 80 s estimated to be 25 to 35 square miles per year Accounts for 80% of U.S. coastal wetland losses Over 1 million acres lost in past century

8 The Causes are Both Natural and Induced

9 Natural Causes Subsidence due to Consolidation of the Alluvial Deposits Down Warping of the Continental Plate due to the Weight of the Delta Deposits

10 Induced Causes Alteration of the Natural River System And a reduction of sediment Construction of Canals for Transportation and Access for Oil and Gas -Canal Banks Create Impoundments -Salinity Intrusion -Boat Wake Erosion Removal of Subsurface Fluids

11 The Principal cause is the alteration of the natural river system The River is no longer building land to compensate for the natural loss of land

C. - 1600 B.C. Teche 1900 B.C. - 700 B.C. St. Bernard 800 B.C. - 300 B.

12 Alexandria Ancient & Modern Courses of the Mississippi River Baton Rouge Lake Charles Lafayette New Orleans Cocodrie 2600 B.C B.C. Teche 1900 B.C B.C. St. Bernard 800 B.C B.C. Lafourche 65 A.D A.D. Modern 900 A.D. - PRESENT

13 Deltas of the Mississippi

14 The Eroding Marsh is actually more Productive than a solid marsh because of a greater shore water interface

15 Until it Entirely Erodes Away and becomes open water

16 Prior to recent times, there was always a new Delta Lobe to provide new marsh to compensate for marsh loss in abandoned delta lobes.

17 That is not happening now - the delta building process has been altered

18 Some History

19 1831 Shreve s Cut Captain Henry M. Shreve, dug a cut across the narrow neck of Turnbull's Bend. The origin of the term "Old River" 1839, the State of Louisiana began to dislodge a 30-mile-long log jam in the Atchafalaya and open up the river to navigation.

22 The Atchafalaya is a shorter outlet to the Gulf of Mexico miles compared to 315. The removal of the log jam allowed the Atchafalaya to capture more and more of the Mississippi's flow.

23 The Mississippi River Commission engaged Harold N. Fisk and a team of geographers and geologists to investigate Fisk, H. N., 1944, Geological Investigation of the Alluvial Valley of the Lower Mississippi Valley, Vicksburg, Mississippi, Mississippi River Commission

24 The Paradigm: We Need To Prevent the River from Changing Course

25 Because of the Consequences for: Navigation Flood Control Water Supply

26 The solution was the construction of the Old River Control Structures

27 With the Congressional Mandate to maintain the 1950 distribution of flows -70% down the Mississippi and 30% down the Atchafalaya

28 The Unintended Consequence is that a significant portion of the sediment in the system goes off the edge of the continental shelf.

30 It will take an act of Congress to make any change.

31 I Propose a New Paradigm: How do we allow the River to Change its Course, while providing for the Flood Control, Navigation and Water Supply needs of the Lower Mississippi River

32 The River Needs to be Re- Engineered as a Sediment Delivery System

33 The River Needs to be Re- Engineered as a Sediment Delivery System With the Constraint of Maintaining Navigation, Flood Control and Freshwater Delivery

34 The Engineering is Relatively Simple

35 The Engineering is Relatively Simple It is the Economics and Politics that Will Make or Break your Project

36 But It can be Done

37 And (IMHO) It is the Only Viable Solution

38 Because Navigation Trumps Everything

39 What is the problem? You divert 10% of the flow and 10% of the sediment and you have 90 percent of the flow and 90% of the sediment remaining in the river channel.

40 The problem is that you still have 100% of the channel.

41 And Navigation Trumps Everything

42 Winer, H. (2006), A New Paradigm for Managing the Lower Mississippi River, 30th International Conference on Coastal Engineering, pp , San Diego, CA Winer, H. (2007), Re-Engineering the Mississippi River as a Sediment Delivery System, Proceedings of Coastal Sediments 07 Conference, pp , ASCE Winer, H (2011), Re-Engineering the Mississippi River as a Sediment Delivery System, Proceedings, Symposium to Honor Dr. Nicholas C. Kraus, Journal of Coastal Research, Special Issue, No. 59, pp

MISSISSIPPI RIVER DELTA OVERVIEW

MISSISSIPPI RIVER DELTA OVERVIEW Science and Engineering Special Team Conference Louisiana State University October 9, 2012 Introduction Basics of the Mississippi Delta Natural and Human-Induced Land Loss