Francisco J. FLORES-MONTOYA (1) , Luis M. GARROTE (2) , Francisco J. MARTIN- (2) (1) Confederación Hidrográfica del Tajo. Av. Portugal, 81. 28011 Madrid (Spain) (2) Universidad Politécnica de Madrid. ETS Ingenieros de Caminos. Ciudad Universitaria s/n
An analysis of the hydrologic regime of the Tagus basin in the last 60 years is presented in this paper. A detailed study was made of the hydrologic characteristics of time series of precipitation and streamflow in the basin. The study focused on drought occurrence. Fourteen hydrologic regions were analyzed, obtaining basic statistics (duration and intensity of departures below the mean and other quantiles) to identify recent tendencies in mean values and variability. The study showed an apparent increase of the frequency and magnitude of droughts in the basin during the 80's and 90's, although the length of the series is short to discriminate between natural long-term variability and man-induced climate change. To conclude, some implications for water planning under non-stationary hydrologic conditions are ...