Monitoring Program Design - Coastal Lagoons: Ecosystem Processes and Modeling for Sustainable Use and Development - page 309

7.2.1 M ONITORING FOR M ETEOROLOGICAL

AND H YDRODYNAMIC P ARAMETERS

Hydrodynamic models are the basis for ecosystem modeling. They include the
background chemical and biological processes in the lagoon ecosystem: transport
processes, internal water mixing and water exchange with adjacent open areas,
vertical mixing, and interaction with the bottom.
Hydrodynamic modeling is the furthest developed type of modeling, but in the
case of lagoons the implementation of models is rather difficult due to the technical
difficulties in obtaining enough field data to calibrate the model for any type of
application. The high variability of current patterns, its local peculiarities because
of bathymetry variations, the complicated nature of water exchange between lagoons,
and the adjacent open water body—all of these factors cause a dramatic increase in
monitoring data needed for implementation of 2D and especially 3D hydrodynamic
models as described in Chapter 6. An optimal monitoring strategy aimed at both
future model applications and type of modeled processes is the key issue for reaching
reasonable model precision at a reasonable price.
In lagoons, the major driving forces are usually wind stress, water level changes
related to tides and wind action, density gradient of different origins, and direct
atmospheric pressure ( see Chapter 3 for details). Therefore, for hydrodynamic mod-
els, the following meteorological measurements are crucial:

• Wind speed
• Wind direction
• Barotropic pressure
• Precipitation and evaporation
• Solar radiation
• Cloudiness
• Air temperature
• Humidity

The list of monitored hydrodynamic parameters usually depends on the moni-
toring goals, but generally includes:

• Flows, salinity, and temperature through the lagoon entrance
• Discharges and water temperature from all rivers and artificial outlets
• Level variation at the open lagoon entrance
• Level variation at some points remote from lagoon entrances
• Current, salinity, and temperature vertical profiles at monitoring points
inside the lagoon
• Spatial variation of salinity and temperature in the lagoon
• Wind wave height and spreading direction
• Parameters related to turbulent mixing
•

Tidal characteristics of the adjacent marine area

The most critical hydrodynamic parameter is water exchange at entrances from
the open sea. There are different types of water flows, including steady flows, pulsing