Post on 14-Apr-2017
Canal del Dique
Coastal impact assessment using Delft3D
Johan Henrotte, Marcela
Busnelli, Mathijs van Ledden
4 November 2015
Canal Del Dique | 4 November 2015
Canal Del Dique - Introduction
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Colombia, Caribbean Sea
120 km canal, 400 years old
Connection Rio Magdalena at
Calamar and Cartagena
Canal Del Dique | 4 November 2015
Canal Del Dique - Introduction
Canal Del Dique system is
part of the old delta of the Rio
Magdalena
Area of 5500 km2 with large
lakes, wetlands of approx. 870
km2
Two national parks in coastal
zone (Rosario and San
Bernado Corals)
Canal Del Dique | 4 November 2015
Key problems with Canal Del Dique
Widening has resulted in strong
increase in discharge and sediment
flux through Canal Del Dique
Sedimentation in Canal itself
requires substantial dredging near
entrance
Degradation of the swamps/marshes
with decreasing productivity and
quality of fishing resources
Fresh water and fine sediments
negatively affect marine
ecosystems in coastal zone
Canal Del Dique | 4 November 2015
Key problems with Canal Del Dique – coastal zone
Canal Del Dique | 4 November 2015
Key problems with Canal Del Dique – coastal zone
Canal Del Dique | 4 November 2015
Canal del Dique project
The December 2010 flood triggered the start of an integrated approach to solve these
issues in the Canal del Dique system.
Environmental restoration of Canal del Dique
Studies, design and implementation of measures to restore the environmental
conditions and improve navigation on the Canal
Part of these studies:
A comprehensive coastal system study to assess the potential impacts of the
measures in the coastal zone
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Canal Del Dique | 4 November 2015
System description
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Canal del Dique
Rio Magdalena
Bahia de Barbacoas
Bahia de Cartagena
Islas de Rosario
Canal Del Dique | 4 November 2015
Characteristics of the system
Micro-tidal system
No significant phase difference between the Bay of Barbacoas and the Bay of
Cartagena observed
Wind speed very low (average wind speed less than 5 m/s)
Moderate wave climate, both bays well protected
Strong stratification observed in the bays
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Canal Del Dique | 4 November 2015
Stratification in Bay of Cartagena (measurements)
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Canal Del Dique | 4 November 2015
Stratification in Bay of Cartagena (measurements)
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Canal Del Dique | 4 November 2015
Model setup
Regional Model (3D)
Open Boundaries: Riemann
Boundary and initial conditions obtained from
HYCOM y de TOPEX 7.2
Turbulence model: k-epsilon
σ layer used in the vertical
20 vertical layers
Detailed Model (3D)
Open boundaries: Riemann
Boundary conditions obtained from regional model
(nesting)
The outlets are shematized as discharge points.
Information obtained from CDD SOBEK model
Turbulence model: k-epsilon
σ layer used in the vertical
10 vertical layers
Canal Del Dique | 4 November 2015
Suspended Sediment Transport
DELFT3D-SED online
3 sediment fractions used
Coarse (6.9 mm/s)
Medium (0.35 mm/s)
Fine (0.011 mm/s)
Sediment concentrations at 5 outlet locations obtained from CDD SOBEK model
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Canal Del Dique | 4 November 2015
Bathymetry
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2013/2014Survey data
Nautical charts
Canal Del Dique | 4 November 2015
Verification HYCOM-Delft3D
HYCOM Delft3D
23 November 2013
Canal Del Dique | 4 November 2015
Verification HYCOM- Delft3D
HYCOM Delft3D
1 March 2014
Canal Del Dique | 4 November 2015
Calibration - Tide
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Canal Del Dique | 4 November 2015
Calibration - Hydrodynamics
Measured & modelled discharges through Boca Chica and Boca
Grande at Bahia de Cartagena
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-4000
-3000
-2000
-1000
0
1000
2000
3000
27/05/2014 15:36 27/05/2014 16:48 27/05/2014 18:00 27/05/2014 19:12 27/05/2014 20:24 27/05/2014 21:36 27/05/2014 22:48 28/05/2014 00:00
Q[m
^3/s
]
BOCA GRANDE - Modelo
BOCA CHICA - Modelo
Canal del Dique
TOTAL - Modelo
BOCA CHICA - Mediciones
BOCA GRANDE - Mediciones
TOTAL Mediciones
Balance basado en los niveles de agua medidos
Boca Grande
Boca Chica
Bahia de Cartagena:
8378ha
Canal Del Dique | 4 November 2015
Calibration – Salinity profiles
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Canal Del Dique | 4 November 2015
Calibration - profiles
Comparison measured and modelled sediment concentration, salinity and temperature
for entire survey campaign November
Only upper 0.5 m of water column
Model results are reasonable (temperature, suspended sediment) to well (salinity) in
line with the measurements
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Canal Del Dique | 4 November 2015
Impact assessment
Sediment Concentration Salinity Temperature
Based on model simulations the sediment concentration, salinity and temperature
determined at the top 2m of the water column
- Maximum sediment concentration and temperature
- Minimum salinity
Canal Del Dique | 4 November 2015
Results Impact Assessment
Minimum salinity concentration in top 2 m of water column for different alternatives
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Reference Alternative 1 Alternative 2 Alternative 3
Canal Del Dique | 4 November 2015
Conclusions
A 3D model has been constructed to simulate the flow, salinity and suspended
sediment concentration profiles in the bays and Mar Caribe
σ layer used in the vertical, (z-layers was not yet fully operational for sediment
modelling)
DELFT3D-SED was used for sediment modelling
The model matches quite well the measurements at the Islas del Rosario but also in
the Bay of Cartagena and the Bay of Barbacoas in November 2014 regarding
discharges, salinity and suspended sediment concentrations profiles
The two validation periods (March and May 2014) show that the model performance
performs reasonable for the salinity profiles
Impact assessment shows significant reduction of fresh water in coastal area for
alternative 2 and alternative 3.
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Canal Del Dique | 4 November 2015 24
> Thank you for your attention
johan.henrotte@rhdhv.com
Canal Del Dique | 4 November 2015
DELFT3D-SED settings
Parameter DELFT3D-SED ONLINE Unit
Critical bed shear stress for erosion (or
resuspension) 0.5 N/m2
Critical bed shear stress for deposition 1000 N/m2 (dummy value)
Settling velocity (coarse fraction) 6.9 mm/s
Settling velocity (medium fraction) 0.35 mm/s
Settling velocity (fine fraction) 0.011 mm/s
Specific density of sediment 2650 kg/m3
Dry bed density kg/m3
Erosion parameter 2x10-4 kg/m²/s
Initial sediment layer thickness 0 m
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