1 EXTREME RAINFALL RATES AND PROBABLE MAXIMUM PRECIPITATION

One of the most important climatic features that characterize a territory is its pluviometric regime and, in particular, the extreme rainfall rates produced in the area. Their knowledge is essential for planning hydraulic works and for designing rainwater drainage systems and flood prevention. In addition, the behavior of this variable can be very useful for the evaluation of possible effects of the climatic change. In this chapter we summarize the methodology used in the calculation of the frequencies associated to maximum precipitations expected in an area according to rainfall duration. Results about the probable maximum precipitation in 24 hours for the 145 pluviometric stations of Catalonia are also shown. The obtained spatial distribution shows rainfall amounts in the range 200-550 mm, in a good concordance with the annual average distribution but with some exceptions caused probably by the different meteorological scales involved in each case