Use of the model framework

The current model framework can be used to answer different types of questions. It is important to clearly distinguish different ways of using the modeling framework, so that the most appropriate level of detail and accuracy is used/respected for these inherently different applications. Below we outline a number of possible uses of the modeling framework and briefly describe how this can be applied in those cases.

Analysis of suitability and trends across Flanders¶

The impact of groundwater levels on yield is a complex interaction of climate, soil, groundwater dynamics and crop. It is therefore interesting to look at the scale of Flanders to see whether certain trends or spatial patterns can be found. Such a regional analysis for the whole of Flanders then broadly reflects the suitability of certain regions/areas for certain crops, enables us to identify and quantify types of stress and to highlight major trends in space and/or time.

The basic data layers as shown in the Model framework to evaluate the suitability of groundwater regime for crop growth are suitable for this. These data layers, which cover Flanders, can of course always be improved, but the level of detail is sufficient for a regional analysis.

Attention!: Since the timing of drought in the growing season can be decisive for crops, we applied a sine function based on the average highest (GHG) and average lowest (GLG) groundwater levels at locations where groundwater dynamics are correlated with rainfall. Where this was not the case, we worked with an average groundwater level that remains constant throughout the year.

Exploratory analysis of contrasting groundwater levels at a given location¶

In recent years, there have also been more and more small-scale actions in Flanders that can have an impact on the groundwater levels: level-controlled drainage, dams, wetting of a part of the stream valley, etc. Also there, people would like to be able to estimate how these interventions will affect one or more agricultural plots. One then looks for a rough, exploratory simulation of harvesting at a certain location where no additional information is yet available (i.e. local groundwater measurements/models, local weather data, accurate soil data).

The basic data layers described in the Model framework to evaluate the suitability of groundwater regime for crop growth are also suitable for this. Users should be aware that this is a rough approximation of reality, but it can be used to compare contrasting situations. If it is possible to install a monitoring well to check the current groundwater level and its dynamics or if monitoring well measurements are already available on https://www.dov.vlaanderen.be/, it is advisable to use this information or at least check whether the measured groundwater levels correspond on average with the general groundwater map layer.

Detailed impact analysis in large-scale rewetting projects¶

Finally, large-scale rewetting projects are planned in some areas that will bring about substantial changes in groundwater levels for a larger area. Ecohydrological studies are usually also carried out in these types of projects. Here too, it is important to estimate the impact of the rewetting on agricultural activities in order to evaluate whether the plans are feasible and what accompanying policy can be developed for the affected farmers if a negative impact is indeed expected.

For this type of customization, the model can be used to calculate the impact of current and future groundwater levels for all plots in the affected area. In this case, the input data for the model must be more detailed than the general Flemish data layers, especially with regard to groundwater levels. This can come from local groundwater measurements or from real groundwater models for that area that are calibrated with local data. Such models are then often available, precisely because an ecohydrological study is also being set up.