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Climatic conditions in the Mediterranean area (i.e. long drought periods and rainfall concentration in a few storm events) favour soil erosion and land degradation. In this area, several studies show that more that 80% of soil losses are caused by 5 to 10% of the rainfall events. The temporal and spatial analysis of these high erosivity rainfall events is a key factor to evaluate trends in erosion and desertification risk.

We analysed spatial and temporal trends in the ten annual maximum rainfall days from 97 pluviometric stations in the Region of Valencia (E Spain) for the normal period 1961-1990.

The main results are as follows:

1) The proportion of annual rainfall falling during the day, with maximum rainfall increases in 37% of the stations, and decreases in the 15% of the stations.

2) The proportion of annual rainfall falling when considering all data except the 10 days with higher rainfall volume, increases in 13% of the stations, and decreases in 33% of the stations.

3) We discuss results in relation to the spatial distribution of the stations and to the origin of rainfall events.