Chapter III
Numerical Modeling
35
III.3. Methodology of Study
III.3.1. Generation of the mesh
To ensure comprehensive analysis and minimize errors that can affect simulation outcomes, both
the marina and Algiers Port have been included as study areas. The regional scale chosen covers
approximately 15.27 km extends from Cap Caxine in the west to Cap Matifou in the east,
passing through Algiers Bay. Additionally, a distance of 19 km north of the marina is
considered.
This scale allows account the coastal features and various structures present in both the marina
and Algiers Port, which can potentially impact water movement. By considering the
hydrodynamic effects of waves in both areas, a more comprehensive understanding of their
impact on the marina and Algiers Port can be achieved.
Input bathymetric data for the mesh
The bathymetry utilized in this study was generated by combining data from three different
sources: field data, NAVIONICS, and GEBCO. For the marina area and Algiers Port,
comprehensive bathymetric data were available, covering both the interior of the basin and the
areas outside the protective structures.
To obtain the bathymetry of Algiers Bay, a digitalization process was employed on the
NAVIONICS SonarChart™ map, specifically the 2021 edition. This map was scaled at
1/250,000 and provided varying resolution ranging from 100 to 0.5 meters, transitioning from
offshore to the coastline (ALEM.A and SAF.B, 2021).
For depths exceeding -200 meters, the GEBCO database served as the primary data source.
However, to enhance the accuracy and detail, additional bathymetric information was
incorporated. This included digitizing marine charts specific to the central Algerian region and
incorporating previously developed bay-scale bathymetry data.
The ArcGIS 10.4 software package, developed by Esri (Environmental Systems Research
Institute), was employed for this purpose. ArcGIS encompasses several interconnected modules,
such as ArcMap, ArcScene, and ArcCatalog, enabling efficient geographic information system
(GIS) workflows.
In order to integrate the bathymetric data into the MIKE21 modeling software and minimize
errors during the simulation process, a conversion process was necessary. The ArcMap shapefile
bathymetry data were transformed into XYZ files using the conversion tool available within the
ArcToolbox. This conversion facilitated the compatibility of the bathymetric data with MIKE21
for subsequent analysis and simulations.
After generating the mesh, it is necessary to interpolate the bathymetry points onto the mesh
grid. Various interpolation methods can be employed regardless of the type of mesh used. The
Numerical Modeling
35
III.3. Methodology of Study
III.3.1. Generation of the mesh
To ensure comprehensive analysis and minimize errors that can affect simulation outcomes, both
the marina and Algiers Port have been included as study areas. The regional scale chosen covers
approximately 15.27 km extends from Cap Caxine in the west to Cap Matifou in the east,
passing through Algiers Bay. Additionally, a distance of 19 km north of the marina is
considered.
This scale allows account the coastal features and various structures present in both the marina
and Algiers Port, which can potentially impact water movement. By considering the
hydrodynamic effects of waves in both areas, a more comprehensive understanding of their
impact on the marina and Algiers Port can be achieved.
Input bathymetric data for the mesh
The bathymetry utilized in this study was generated by combining data from three different
sources: field data, NAVIONICS, and GEBCO. For the marina area and Algiers Port,
comprehensive bathymetric data were available, covering both the interior of the basin and the
areas outside the protective structures.
To obtain the bathymetry of Algiers Bay, a digitalization process was employed on the
NAVIONICS SonarChart™ map, specifically the 2021 edition. This map was scaled at
1/250,000 and provided varying resolution ranging from 100 to 0.5 meters, transitioning from
offshore to the coastline (ALEM.A and SAF.B, 2021).
For depths exceeding -200 meters, the GEBCO database served as the primary data source.
However, to enhance the accuracy and detail, additional bathymetric information was
incorporated. This included digitizing marine charts specific to the central Algerian region and
incorporating previously developed bay-scale bathymetry data.
The ArcGIS 10.4 software package, developed by Esri (Environmental Systems Research
Institute), was employed for this purpose. ArcGIS encompasses several interconnected modules,
such as ArcMap, ArcScene, and ArcCatalog, enabling efficient geographic information system
(GIS) workflows.
In order to integrate the bathymetric data into the MIKE21 modeling software and minimize
errors during the simulation process, a conversion process was necessary. The ArcMap shapefile
bathymetry data were transformed into XYZ files using the conversion tool available within the
ArcToolbox. This conversion facilitated the compatibility of the bathymetric data with MIKE21
for subsequent analysis and simulations.
After generating the mesh, it is necessary to interpolate the bathymetry points onto the mesh
grid. Various interpolation methods can be employed regardless of the type of mesh used. The