SIMULATION OF THE WATER BUDGET AND THE RIVER
FLOWS OF THE RHONE BASIN FROM 1981-1994
by P. Etchevers, C. Golaz, and
F. Habets
As a first step toward the simulation of the continental water cycle at a regional
scale, simulations using a Soil-Vegetation-Atmosphere Transfer (SVAT) model
coupled with a hydrological model was done on the Rhone basin for one year
(1987-1988). Because of the strong snow component of the basin, a detailed multi-layer
snow model has been added to the original modeling system. The present
analysis covers a longer time period in order to examine the inter-annual variability
of climatic conditions and streamflows. The Rhone basin simulation has been
extended to 14 years (from 1981-1994). The observed atmospheric forcing has
been interpolated in time and space with a system especially adapted to the Alps
mountains. Although only a limited calibration using observed discharges was
done, the model results compare fairly well with the daily observed discharges at
145 gauging stations located on the largest rivers of the catchment. Poor results
are obtained for some of the smaller catchments (smaller than 1000 km squared), possibly
because of inaccuracies in the interpolated atmospheric forcing at small spatial
scales. The evolution of the simulated snow pack is in good agreement with the
daily observed snow depths at 24 high altitude stations located between 1500
and 3000 m in the Alps. The surface water budget shows large spatial variations
due both to vegetation and climatic conditions. The inter-annual variability of
the water table is strongly related to the variability of precipitation with positive
storage of water for wet years.
Reference