Rainfall Frequency Studies for Central Saudi Arabia

A frequency analysis of rainfall data for six stations in Central Saudi Arabia is presented. The Gumbel type-1 distribution is used to predict design storms for particular durations (10-min to 12-hr) and for particular return periods (2 to 50-yrs). Analysis of data for each individual station as well as regional analysis are carried out using annual series. The area under study is divided into two zones by considering the rainfall and topographical characteristics, and depth-duration-frequency relationships are derived for each zone. These relationships are recommended for the design of hydraulic structures (i.e. storm sewers and drainage channels) in the area.