This document summarizes a large-scale modeling effort of nutrient dynamics, wetland vegetation, and morphodynamics in the Lower Mississippi Delta and surrounding basins. The goals are to gather field observations to improve understanding of estuarine processes and validate numerical models, develop an ecological and morphodynamic model, and use the model to analyze restoration activities. The modeling approach integrates hydrodynamic, water quality, vegetation, and sediment transport modules. Extensive field data is being collected on bathymetry, vegetation/soils, sediment diversions, and other parameters to develop and validate the integrated model.

1. L A R G E S C A L E N U T R I E N T , W E T L A N D
V E G E T A T I O N A N D M O R P H O D Y N A M I C
M O D E L I N G O F T H E L O W E R
M I S S I S S I P P I D E L T A A N D S U R R O U N D I N G
R E C E I V I N G B A S I N S
Ehab Meselhe1 and Johannes Smits2
1The Water Institute of the Gulf
2Deltares

2. Lower Breton
Mid-Breton
Lower Barataria
Mid-Barataria
Sediment
Diversions
CRMS sites
Source: CRMS
P OT E N T I A L S E D IME N T D I V E R S I O N S
Likely flow conditions:
• ~35-75,000 CFS (~ 1,000-2,100 CMS)

3. P R O J E C T G O A L S
Gather field observations to improve understanding of
the estuarine dynamics and to validate the numerical
model
Produce a validated Ecological and Morphodynamic
numerical model
Use the model to analyze the final array of restoration
activities

4. MO D E L I N G A P P R O A C H
Hydrodynamics
Nutrient Dynamics Morphodynamics
Integration of Nutrient and Morphodynamic Modules
to perform production runs
Vegetation

5. Delft3D-WAQ
MODELING APPROACH DIAGRAM
Delft3D-FLOW
Nutr. Light Phytop. Org. Mat. Veg.
Veg. changes
Fine sediment deposition
Soil strength/surface drag




LAVegMod
EwE / CASM
5
Data Input: Atm, GOM, MR
Data Input: Atm, GOM, MR
Chl. a
Water Column
Soil/Sediment Bed
Water depth
Temperature
Salinity
Turbidity
Flow field
Hydro. Morph. Susp. Sed.
Processes
Processes
(sand, silt and clay)

6. E S S E N T I A L D E L F T 3 D MO D E L O U T P U T
6
Hydrodynamics
(2D throughout estuary)
Water Quality Vegetation/Soils Sediment
Water-level
Velocity
Salinity
Water temperature
Nitrogen (PON, DON, NH4, NO3)
Phosphorus (POP, DOP, PO4)
Silicate (SiO2)
water column and soil layers separately
Chlorophyll a
Dissolved Oxygen
Suspended sediment – fines
Coverage of 7 species –
distribution
Above and below ground
biomass
Suspended
sediment –
change in bed
elevation due to
accumulation or
erosion
% diversion
sediment retained
(estimated in post
processing)

7. 7
D ATA C O L L E C T I O N
Bathymetry and Elevation
Continuous
Splay Evolution
Estuarine Open Water
Wetland Soils and Vegetation
Sediment Diversion Initial Conditions

8. 8
Bathymetry and Elevation

9. Continuous Deployment in Barataria and Breton:
• 10 YSIs (at Hydrological Water Quality Stations)
• 2 LISST (at Hydrodynamics/Sediment Transport/Ecological Stations
(HSTE))
• 2 Aquadops (at HSTE Stations)
• 2 Meteorological stations (1 in each basin, at HSTE Stations 1,2)
9
Continuous

10. C O N T I N U O U S + T R A N S E C T S I T E S
10

11. Caernarvon Outfall and Big Mar Case Study
Splay Evolution

12. Data collection in Barataria and Breton basins along a salinity gradient (transect):
15 sites in Barataria Bay estuary
11 sites in Breton Sound estuary
Estuarine Open Water Parameters
During June and August 2014, at each site:
Secchi disk depth
Submerged Aquatic Vegetation (SAV, +/-); % cover
Water column profile (salinity, temperature, depth, pH, dissolved oxygen,
chlorophyll a and turbidity with YSI EXO2 water quality sonde and suspended
sediment with LISST)
Dissolved inorganic nutrients (NH4, NO2+NO3, PO4, SiO4, TN, TP)
Phytoplankton community composition (major groups, HABs)
Chlorophyll a
Total Organic Carbon (TOC) and Dissolved Organic Carbon (DOC)
Total Suspended Sediments (TSS)
Sediment TOC, % water content (4 slices: 1 cm, then every 5 cm)
Sediment Total Nutrients (TN, TP, TC, TFe)
Estuarine Open Water Sampling
12

13. E S T U A R I N E O P E N WAT E R T R A N S E C T
13

14. P H OTO S - B R E TO N A N D B A R ATA R I A
14

15. Data collection in Barataria and Breton basins:
Wetland Parameters
End of growing season 2014 (1 data collection trip per basin).
Followed CRMS protocol.
Soil porewater nutrients (NH4, NO2+NO3, PO4, TN, TP)
Soil porewater salinity
Vegetation aboveground biomass (live, dead), taxa, density, height; tissue
TN/TP content; stem diameter; height
Vegetation belowground biomass (live, dead) and tissue TN/TP content
Soil organic matter (LOI) and bulk density
Soil TOC, TN, TP, TFe
Soil shear strength
Wetland Vegetation and Soil Sampling
15

16. WE T L A N D S AMP L I N G
16

17. S AMP L I N G WE T L A N D S V E G E TAT I O N
A N D S O I L
17

18. A C K N OWL E D G E M E N T S - F U N D I N G
18
State of Louisiana Coastal and Protection Restoration Authority

19. A C K N O W L E D G E M E N T S - T E A M M E M B E R S
19
The Water Institute of the Gulf
Melissa Baustian
Ehab Meselhe
Mead Allison
Hoon Jung
Ashok Khadka
Leland Moss
Cyndhia Ramatchandirane
Dallon Weathers
Ann Hijuelos
Tim Carruthers
Denise Reed
Deltares
Johannes Smits
Valesca Harezlak
Bas Van Maren
Michel Jeuken
UL Lafayette Team
Scott Duke-Sylvester
Jenneke Visser
LSU Team
Samuel Bentley
Kehui (Kevin) Xu

20. Please visit us at:
www.thewaterinstitute.org
@TheH2OInstitute
Follow us:
The Water Institute
of the Gulf
THANK YOU!