MODELING RIVER FLOWS WITH HEAVY TAILS

Recent advances in time series analysis provide alternative models for river flows in which the innovations have heavy tails, so that some o f the moments do not exist. The probability of large fluctuations is m uch larger than for standard models. We survey some recent theoretical developments for heavy tail ti:me series models and illustrate their practical application to river flow data from the Salt River near Roos evelt, Arizona. We also include some simple diagnostics that the pract itioner can use to identify when the methods of this paper may be usef ul.