Frequency Analysis of Annual one Day Maximum Rainfall at Kassala State, Sudan

Abstract

Rainfall is the main driving force in the hydrology of arid and semi-arid regions. The hydrological data in arid and semiarid regions is lack due to the absent of field measurement and scarcity of data. The hydraulic design and management of water systems are not based on the long-term average of rainfall records but on particular rainfall depths that can be expected for a specific probability or return period. These rainfall depths can only be obtained by a thorough analysis of long time series of historic rainfall data. The most common approach for determining design storm events is frequency analysis. The aim of this paper is to conduct frequency analysis of annual daily maximum rainfall data for five stations in Kassala State using Hyfran-Plus software. Frequency rainfall analysis showed that the Log person type 3,  Person type 3, Three-Parameter Log Normal, Three-Parameter Log Normal and Normal distributions provided the best-fit probability distribution at Aroma, Kassala, Mekali, Goz Rigab and Halfa EL Gadeeda rainfall gauging stations respectively. The analysis has shown that the maximum daily rainfall record about 118 mm in Aroma station. The maximum daily rainfall with a return period 50 year is about 103 mm in Kassala station.