| Résumé
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Groundwater
modelling with
deterministic model is a complicated process, especially in complex
aquifers
where the quantity and the quality of the measured data arc not
satisfying. The
unconfined alluvial aquifer is the main water resource in the lower valley of Vat
river, French Riviera,
but it faces a threat of shortage and pollution. Despite numerous
previous
studies, the dynamics of the groundwater flow in the alluvial aquifer
and the
characteristics of the rivet-aquifer exchanges are still partially
unknown.
Therefore the local water management service requires a decision
support system
PSS) based on numerical models to ensure a better groundwater
management. A
hydraulic model is set up with FEFLOW software by considering
precipitation,
evapotranspiration, groundwater extraction and river/aquifer exchanges.
The
non-documented groundwater extraction for agricultural use and the
transfer
rates in the riverbed along the river have been calibrated. The model
has been
validated with a simulation of 7266 days. The model is applied to
simulate the
scenarios of flood and drought events, the pollution events in the
unconfined
aquifer in the valley and the seawater intrusion in the estuary of Var
river.
These case studies contribute to increase the knowledge of the aquifer.
A first
conception of the DSS tool is presented as the last example of model
application. A coupling interface is developed thanks to a Java program
that
enables an automatic exchange of data between the groundwater flow
model and
the surface water flow model built with MIKE 21. More tests should be
done to
validate the coupling interface.
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