Statistical Behavior of Rainfall in Egypt

Abstract

The extreme rainfall events have critical impacts on hydrologic systems and the society, especially in arid countries. Recently, Egypt has been subject to some flash floods, due to extreme rainfall events, in particular regions (e.g., Sinai, North Coast, and Upper Egypt) that caused severe damages in lives and vital infrastructure and buildings. This chapter investigates, therefore, the statistical characteristics of rainfall over Egypt based on historical daily rainfall records at 30 stations throughout the country. Six types of rainfall data were extracted from daily records: monthly rainfall, annual rainfall, the monthly number of rainy days, the annual number of rainy days, monthly maximum daily rainfall, and annual maximum daily rainfall. Rainfall frequency analysis, based on the generalized extreme value (GEV) distribution along with the L-moments parameter estimation method, was applied to analyze annual maximum rainfall series. Results of the numerical application indicate a great variation over the whole country in all different aspects of rainfall. The rainfall indices have higher values in the north of the country than those in the middle and the south. Also, the annual maximum daily rainfall data in the case study has been well described by the GEV distribution with negative values of the shape parameter for all stations except only one station (Ras Sedr).