An Empirical Model to Estimate Rainfall Intensity Duration in Asaba Metropolis, Nigeria

Abstract

Abstract

One of the most widely used tools in water resources engineering is the intensity-duration-frequency (IDF) relationship. The aim of this research was to create rainfall intensity-duration-frequency curves for the Nigerian city of Asaba. The Nigeria Hydrological Services Agency (NIHSA) in Abuja provided rainfall data that was sorted for frequency analysis. The IDF connection for Asaba was developed using two separate frequency analysis techniques, the Normal and Gumbel distributions. The Talbot IDF equation was used to get the simulated rainfall intensity for the goodness of fit test to derive the curves for each model, with storm durations of 10, 15, 30, 60, 120, and 240 minutes and return periods of 5, 10,15,20, 25, and 30 years. To choose the optimal distribution that matches the data from the goodness of fit test, Microsoft Excel software was used to run Nash Sutcliffe Efficiency (NSE) and Coefficient of Determination (R²) goodness of fit tests. The Gumbel Distribution Method best fits the set data, according to the goodness of fit results. The Normal distribution, on the other hand, produced excellent outcomes. The IDF curves developed in this study are recommended for use as tools for predicting rainfall occurrences and designing hydraulic structures in the study area. In addition, new hydrological stations should be built in the country and appropriately equipped to generate the necessary data for water resource planning and design.