Best Fit and Selection of Probability Distribution Models for Frequency Analysis of Extreme Mean Annual Rainfall Events

Abstract

<p>Frequency analysis of extreme low mean annual rainfall events is important to water resource planners at catchment level because mean annual rainfall is an important parameter in determining mean annual runoff. Mean annual runoff is an important input in determining surface water available for water resource infrastructure development. In order to carry out frequency analysis of extreme low mean annual rainfall events, it is necessary to identify the best fit probability distribution models (PDMs) for the frequency analysis. The primary objective of the study was to develop two model identification criteria. The first criterion was developed to identify candidate probability distribution models from which the best fit probability distribution models were identified. The second criterion was applied to select the best fit probability distribution models from the candidate models. The secondary objectives were:</p