Learning by Doing: Flood Training in Tunisia
A Training on Flood Risk Management, Flood Hazard and Flood Risk Maps took place in Gammarth, Tunisia on October 19-20, 2016.The training’s objectives included: assisting water practitioners in flood risk mapping and the preparation of flood hazard and flood risk maps through the use of a hydrodynamic model; implementing area-specific approaches for the demonstration site; and outlining flood action programmes and flood risk management objectives.
During the first day, the participants were given a theoretical background of water modelling through different approaches (i.e. 1D, 2D, 3D modelling) — with a more in-depth focus on 2D-based approaches, as they are the most widely used for flood modelling. The participants then paired up to form working teams to develop model inputs from data that had been collected previously from the records of the Ministry of Agriculture, Water Resources and Fisheries General Directorate of Water Resources and General Directorate of Dam and Large Hydraulic Structures.
During day two of the event, the participants worked on a flow model – designed from input files related to the Medjerda River Basin area – which was then used to execute and run pre-defined simulations (allowing for sufficient computation time). The participants then discussed the necessity of model calibration and validation, as well as a general method of how to determine which model showed results in closest correlation with real measured water levels and discharges.
The last session of the training consisted in a group exercise. The participants were separated into two groups, with each group asked to analyse the tools and information collected over the two-day-long training and to assess how it could be used to strengthen flood risk mapping in the Tunisian context.
Conclusions of the Training on Flood Risk Management, Flood Hazard and Flood Risk Maps:
- communication with other institutions regarding data collection and data exchange;
- selection of the “most important river reaches” in the Mejerda River basin — i.e. finishing preliminary flood risk assessments;
- collecting relevant topological data (DEM and river channel topology) for selected river reaches, and updating this data regularly;
- preparing hydrodynamic models (both 2D and 1D) for selected river reaches, and using these models for selected hydrological scenarios; and
- preparation of flood hazard and flood risk maps in order to improve flood risk management capacity.