The quantitative water management of the Charente River in France is a major policy concern because of freshwater scarcity in summer. In the context of the SPICOSA project (Science and Policy Integration for Coastal System Assessment) as mentioned below, this policy issue was chosen to apply the System Approach Framework (SAF) methodology. This led to modeling irrigation management strategies to quantify its impacts on various uses.
They built an external hydrological model in HEC-HMS (Hydrologic Engineering Center's Hydrologic Modeling System) and interfaced with ExtendSim to work as a source of forcing. This strategy proved to be more efficient to model water shortages without renouncing the benefits of system-modeling inside the ExtendSim platform and with the advantage of a software dedicated to hydrological modeling. Using this experiment, the paper discusses the case of “in-line”, “on-line”, or “off-line” coupling modes to serve the objectives of policy orientated complex socio-ecosystems modeling.