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Flemming H. Andersen, University of Copenhagen (Denmark)
Simon Stisen, Geological Survey of Denmark and Greenland (Denmark)
Inge Sandholt, University of Copenhagen (Denmark)
Sara Jorreto, University of Almeria (Spain)
Antonio Pulido, University of Almeria (Spain)
Karsten H. Jensen, University of Copenhagen (Denmark)
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A distributed hydrological model, MIKE SHE, has been applied to the semi-arid Andarax River basin, SE Spain, to examine the hydrological behavior and to assess the water resources. The Andarax River basin is characterized by a large spatial variability of landscape characteristics. These characteristics combined with the fact that the availability of geological and hydrological data is rather sparse complicate the hydrological modeling.
The model was calibrated and validated against observed discharge from one station and piezometric heads from six selected boreholes located in the delta region at the outlet to the Mediterranean for the period August 2000 to January 2007. Larger discrepancies are present between observations and simulations than usually seen for more temperate hydrological regimes. Overall the hydrological behavior is characterized by little difference between precipitation and evapotranspiration (ET) and thus little excess precipitation for generation of runoff and recharge. Accurate estimation of recharge over the catchment is crucial for the simulation of the available groundwater resources in the delta region. In the first simulation scenario we only use traditional meteorological data and standard values for the vegetation characteristics. The traditional meteorological data are rather sparse for the Andarax river basin and to improve the estimation of evapotranspiration we use an energy-based two-layer SVAT model and apply remote sensing derived variables as input data. Surface temperature, global radiation, albedo and leaf area index (LAI) are derived from remote sensing images.
We compare the two model simulations and focus in particular on the temporal and spatial distribution of evapotranspiration and recharge, and river discharge.
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