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The climatic variability of southeastern Spain recently produced one of the driest periods of the 20th century, which provoked a marked decrease in river flows. A study of trends was applied to four representative rainfall stations (Granada, Almeria, Murcia and Alicante) and showed that the downward trend is generalised. Three of the stations registered abrupt changes. A study of later decades showed that precipitation fell by 9.2 and 11.7% in Granada and Almeria, respectively, between 1980 and 1989. The decline between 1990 and 1999 was generalised; at the same time the year-to-year variability increased by between 37 and 49%. This variation was most pronounced in the rivers, three of which showed a reduced mean monthly flow of the order of 34% over the period 1980-2003, in comparison to the decade 1969-1979. The decline in flow in spring was somewhat more buffered. The most noticeable impact in the southeastern part of Spain over the last 40 years has been the intensive exploitation of groundwater. This has brought about a general decline in groundwater levels, drying out of springs, abandonment of numerous wells and boreholes, and salinisation of soils and water.