Changes in the hydrological response of a small Mediterranean basin a year after a wildfire
Résumé
This paper presents the results of a study ot" the hydrological consequences of a wildfire in a small
Mediterranean basin during the first 12 months after the event. The Rimbaud basin is a nested sub-basin
of the R&I Collobrier research and experimental network, which has been continuously monitored since
1967. In August 1990, 85% of its surface area was burnt providing an interesting case study to analyse the
hydrological consequences of fire. Models have been calibraicd using a 23 year period before the fire and
they have been used to simulate what the response would have been if tile wildfire had not taken place.
Differences between observed and simulated data are analysed, giving special importance to the changes
in the annual runoffyield and in the flood regimes. There is a 30% increase in the annual runoff yield related
to the reduction in evapotranspiration due to the destruction of the vegetation cover. On the other hand,
there are pronounced changes in the shape of the flood hydrographs, and the flood frequency is greatly
increased. The 10-year return period flow estimated before the fire was exceeded three times in the year
although the rainfall events did not exceed the l-year return period 12 h rainfall. The quantity and quality
of the data collected during the nre-fire period and the possibility of comparing the hydrological responses
of similar basins differently affected by fire, give a special relevance to this case study.
Domaines
Hydrologie
Origine : Fichiers produits par l'(les) auteur(s)
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