Modeling of Short Duration Rainfall Intensity Duration Frequency(SDR-IDF) Equation for Basra City

Abstract

The Rainfall Intensity-Duration-Frequency (IDF) relationship is one of themost commonly used tools in water resources engineering, either for planning,designing and operating of water resource projects or for various engineeringprojects against floods. The objective of this study is to develop an empiricalformula to estimate rainfall intensity for any duration and any return period withminimum effort. Daily rainfall data for years 1980-2010 from Iraqi MetrologicalOrganization and Seismology was used in this study. Hershfeildʼs method wasused to estimate the short duration rainfall intensity from daily rainfall data.Various distribution functions were used for analysis and Chi-Square goodness tofit test were used to identify the best statistical distribution among them. Studyshowed that Log Pearson type III is the best probability distribution and the best(IDF)empirical formula was in the form [i=a/(b=td)].