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IMAGINE 2030, climat et aménagements de la Garonne : quelles incertitudes sur la ressource en eau en 2030 ?

Abstract : This report details the main results obtained within the IMAGINE2030 project. IMAGINE2030 is a French national project that aims at assessing future water availability in the 2030s by accounting for changes in both climate and water management. Climate projections for the Garonne basin are generated from IPCC AR4 monthly precipitation and temperature scenarios. A multimodel downscaling framework is applied to derive basinscale transient daily time series from 1950 to 2050. The two rainfall-runoff models GR4J and CEQUEAU calibrated under present climate conditions, provide natural river flows. A warmer climate over the basin induces a decrease in mean annual runoff, a shift in snowmelt in mountainous areas and more severe low flows. The magnitude of changes differs from one basin to another. Two models were developed to simulate the impact of a business-as-usual water management (including reservoir operations, environmental constraint, irrigation practices)on river discharges. Results for the Ariège River at Foix show (1) a decrease in energy production, (2) an earlier filling of reservoirs and (3) an increase in water release in summer to fully respect the imposed minimum discharge downstream to reservoirs. Agricultural demand for irrigation water is assessed within the whole River basin at Lamagistère. The increase in temperature leads to an increase in the irrigation requirement for maize up to 20% in the 2030s. In this context, the supply of water beyond irrigation in this area should be managed cautiously to sustain all the types of demand.
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Submitted on : Friday, May 15, 2020 - 5:06:02 PM
Last modification on : Wednesday, March 16, 2022 - 10:48:08 AM


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  • HAL Id : hal-02593270, version 1
  • IRSTEA : PUB00028876



Eric Sauquet, A. Dupeyrat, F. Hendrickx, C. Perrin, R. Samie, et al.. IMAGINE 2030, climat et aménagements de la Garonne : quelles incertitudes sur la ressource en eau en 2030 ?. [Rapport de recherche] irstea. 2010, pp.149. ⟨hal-02593270⟩



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