The Regional STICS model was implemented on the CRAU area to address the following questions which were identified as key issues by stakeholders:

      - will the aquifer balance be maintained under climatic change at medium term horizon (~2050)?
      - What will be the water amount from the Durance River to preserve to sustain the grass production and the aquifer?

A specific simulation case generator to prepare the STICS crop model multi-simulation was developed and alternatives models were proposed to address land use class that are not simulated by STICS. The quality of the whole chain was evaluated over the 2001-2010 period considering the aquifer level (by combining the regional STICS model to MODFLOW), the irrigation channel discharge and grass yield. Results have shown that the computed recharge led to consistent variations of the aquifer level at the annual and inter annual time scale during a period presenting variable rainfall patterns. The estimation of the amounts of water required by irrigated grass are well reproduced by the irrigation module developed in the simulation case generator. Finally the STICS model offer very good results with yield estimation, the main source of error being the soil characterization.
Climate change impacts on the aquifer recharge and irrigation needs were analysed considering the RCP8.5 scenario and climate date simulated using Aladdin model of meteoFrance. The impacts were evaluated by comparing the 1973-2005 and 2037-2065 periods. Results have shown that rainfall were overestimated by the climatic model whereas the climatic demand is underestimated and therefore water supply issues are attenuated when using such data. The comparison between the periods has shown little change in water demand and recharge. Comparison between the different models has stressed out the interest of using crop model to address the future behavior of crops.