MODELING OF LAND BUILDING IN THE MISSISSIPPI DELTA:

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MODELING OF LAND BUILDING IN THE MISSISSIPPI
DELTA A TEMPLATE FOR RECONSTRUCTION
Wonsuck Kim Gary Parker, University of
Illinois As part of a much larger team led by C.
Paola (NCED) and R. Twilley (CLEAR)
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THE ORIGINS OF OUR LAND-BUILDING TECHNOLOGY CAN
HUMANS JUMP-START THE NATURAL DELTA-BUILDING
PROCESSES OF RIVERS?
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THE NATURAL PROCESS OF DELTA LOBE CONSTRUCTION
AND SWITCHING
Lobe gif from M. Wolinsky
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DELTA MADE BY HUMANS TAILINGS BASIN OF AN IRON
MINE, LABRADOR, CANADA
2.4 km
Sediment disposal rate 24 Mt/yr
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DELTA MADE BY HUMANS TAILINGS BASIN OF AN IRON
MINE, MINNESOTA
3 km
Sediment disposal rate 21 Mt/yr
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WE HAVE DEVELOPED AND VERIFIED NUMERICAL MODELS
THAT DESCRIBE THE OVERALL EVOLUTION OF THESE
DELTAS DECADES INTO THE FUTURE
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HOW MUCH SEDIMENT IS CURRENTLY AVAILABLE FOR
DELTA BUILDING IN THE MISSISSIPPI DELTA?
Input 208 Mt/yr
Atchafalaya River 84 Mt/yr
Lower Mississippi River 124 Mt/yr
Wax Lake Delta 34 Mt/yr
Suspended sediment loads
Atchafalaya Delta 50 Mt/yr
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TEST OF CONCEPT NUMERICAL MODEL OF EVOLUTION OF
THE WAX LAKE DELTA
Atchafalaya River
Mississippi River
Wax Lake Delta
The delta started to formed in 1973, when it
received increased flow from the Atchafalaya
River. Its growth has been monitored ever since.
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OUR MODEL CAN REPRODUCE THE WAX LAKE DELTAS PAST
Before start of delta growth
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THE MODEL CAN REPRODUCE THE WAX LAKE DELTAS PAST
Yellow 38 Mt/yr White 25 Mt/yr (suspended load)
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THE MODEL CAN REPRODUCE THE WAX LAKE DELTAS PAST
Yellow 38 Mt/yr White 25 Mt/yr (suspended load)
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THE MODEL CAN REPRODUCE THE WAX LAKE DELTAS PAST
Yellow 38 Mt/yr White 25 Mt/yr (suspended load)
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THE MODEL CAN REPRODUCE THE WAX LAKE DELTAS PAST
Yellow 38 Mt/yr White 25 Mt/yr (suspended load)
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PREDICTIONS INTO THE FUTURE OF THE WAX LAKE DELTA
HIGH
HIGH
LOW
LOW
HIGH Solid line, 38 Mt/yr LOW dotted line 25
Mt/yr (suspended load)
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MIGRATION OF THE MODEL FROM WAX LAKE TO THE
MISSISSIPPI RIVER BELOW NEW ORLEANS Two
diversions Barataria Bay and Breton Sound (CLEAR
plan)
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POTENTIAL SEDIMENT FOR DELTA BUILDING 45 OF 124
Mt/yr, OR 56 Mt/yr ( 3 iron mines)
45 of floodwater and sediment diverted.
Breton Sound 28 Mt/yr delivered 11 Mt/yr captured
Barataria Bay 28 Mt/yr delivered 11 Mt/yr
captured
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SCENARIOS MODELED
100 year simulations from 2010 Base
case Subsidence 5 mm/yr sea level rise 2 mm/yr
Variant parameters Subsidence 1 mm/yr, 10
mm/yr Sea level rise 0 mm/yr, 4 mm/yr
Image from M. Wolinsky
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
Takes only about 0.1 years to build these initial
deltas
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
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PRELIMINARY RESULTS FOR LAND-BUILDING BASE CASE
Base case 918 km2 of new land
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VARIATION SEA-LEVEL RISE RATE 0 mm/yr,
SUBSIDENCE 5 mm/yr
Solid line variant case Dotted line base case
1002 km2 of new land
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VARIATION SEA-LEVEL RISE RATE 4 mm/yr,
SUBSIDENCE 5 mm/yr
Solid line variant case Dotted line base case
845 km2 of new land
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VARIATION SEA-LEVEL RISE 0 mm/yr, SUBSIDENCE
1 mm/yr
Solid line variant case Dotted line base case
1217 km2 of new land
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VARIATION SEA LEVEL RISE 2 mm/yr, SUBSIDENCE
1 mm/yr
Solid line variant case Dotted line base case
1101 km2 of new land
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VARIATION SEA LEVEL RISE 2 mm/yr, SUBSIDENCE
10 mm/yr
Solid line variant case Dotted line base case
753 km2 of new land
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VARIATION SEA-LEVEL RISE 4 mm/yr, SUBSIDENCE
10 mm/yr
Solid line variant case Dotted line base case
And extra land-building due to organics is not
yet included
Worst case still 701 km2 of new land
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IN ORDER FOR THE DIVERSIONS TO BE
SUCCESSFUL, CONTROL STRUCTURES AND SHORT GUIDE
CHANNELS, NOT OVERFLOW POINTS, ARE NEEDED

• We need to get as much sand as possible into the
  new deltas.
• The present Caernarvon diversion, while helpful,
  delivers mostly mud.
• We know how to build the control structures that
  divert sand as well as mud, because we built
  the Old River Control Structure to regulate flow
  into the Atchafalaya River.

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SLURRY PIPELINES CAN BE HELPFUL TO START
LAND-BUILDING
http//www.lacpra.org/index.cfm?catid0elid0fmi
d0mdpagebuildernid31pid20pnid24tmphome
IF SUSTAINED FOR MORE THAN A FEW YEARS, HOWEVER,
THEY CAN BUILD DELTA SLOPES THAT ARE TOO STEEP.
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NEXT STEP BUILD IN THE FINE STRUCTURE

• The land-building model predicts overall
  topography.
• We are using field measurements to build in the
  statistical structure of
• bars/channels/edge effects/ etc. necessary for
  ecosystem modeling.

Our field effort on the Wax Lake Delta is our
main template.
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NEXT STEP
BUILD IN THE ECOLOGICAL COMPONENTS OF THE NEW
DELTA
Most of these components are already in place at
Louisiana State University and within the CLEAR
group in Louisiana.
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• NEXT STEPS
• CONSIDERATIONS OF SUCH FACTORS AS
• Effect of diversions on Mississippi River
  upstream
• Coastal sediment supply
• Storm surge
• Navigation
• Socioeconomic implications e.g. oyster farms,
  shrimp
• POLITICAL WILL

Levee strengthening will be needed in the short
term
AMBITIOUS PROJECTS ARE POSSIBLE! Parkers
great-grandfather and great uncle were
construction workers on this first bridge to span
the Mississippi River in New Orleans
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Most of the Mississippi Delta, some 10,000 square
miles, lies less than three feet above sea level.
Beset by land subsidence and rising sea levels,
much of this vast area will inexorably sink
beneath the waters by the end of this
century. BRUCE BABBITT
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Most of the Mississippi Delta, some 10,000 square
miles, lies less than three feet above sea level.
Beset by land subsidence and rising sea levels,
much of this vast area will inexorably sink
beneath the waters by the end of this
century. BRUCE BABBITT
OUR REPLY
Before major human intervention, the Mississippi
Delta historically maintained itself with river
slopes on the order of 3 ft of drop per 30 miles
without sinking beneath the waters!
How? The surface is NOT a static board that
will sink because of its low slope it is a
DYNAMIC, self-maintaining surface that keeps
itself from drowning by adding sediment to
balance subsidence.
Think about your bank account.
If you withdraw 1,000 a month every month, you
will go broke before long.
How can you fix the problem?
42
Most of the Mississippi Delta, some 10,000 square
miles, lies less than three feet above sea level.
Beset by land subsidence and rising sea levels,
much of this vast area will inexorably sink
beneath the waters by the end of this
century. BRUCE BABBITT
OUR REPLY
START DEPOSITING 1000 A MONTH!
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WE THINK THAT THE SCIENCE AND TECHNOLOGY EXISTS
TODAY TO REBUILD A NEW, LIVING MISSISSIPPI DELTA
Wax Lake gif from M. Wolinsky