Towards operational guidelines for over-threshold modeling

Annual maximum flood (AMF) sampling remains the most popular approach to flood frequency analysis. An alternative, the "peaks over threshold" (POT) approach, deals with the selection of over-threshold values. However, the POT approach remains under-employed mainly because of the complexities associated with its use. Among the difficulties are the choice of threshold and the selection of criteria for retaining flood peaks. The literature remains sparse and incoherent concerning the various elements and complexities of the POT model. The purpose of the present paper is to shed some light on some of the recurrent and most important questions with regard to the practice of POT modeling, and to make a first step in establishing a set of coherent practice-oriented guidelines for the use of the POT model. This paper reviews tests and methods useful for modeling the process of over-threshold values, the choice of the threshold level, the verification of the independence of the values and the stationarity of the process, and also presents an application. (C) 1994 Elsevier Science B.V. All rights reserved.