Approximation of Rainfall Intensity-Duration Frequency for Owerri Metropolis, Nigeria

One of the most often utilized methods in water resources engineering is the approximation of the Rainfall Intensity-Duration-Frequency (IDF) relationship. The aim of this research is to establish the rainfall intensity-duration-frequency model/curves for Owerri Metropolis, Nigeria. 30 years rainfall data was obtained from the Nigeria Hydrological Services Agency (NIHSA) and sorted for purpose of frequency analysis. Storm durations of 10, 30, 60, 120 and 240 minutes, and for respective return periods of were adopted for the derivation of the models. The generalized empirical technique was used to develop the IDF curves for this study. The Nash-Sutcliffe efficiency (NSE), Mean Absolute Error (MAE), Coefficient of Determination ( ), and Root Mean Square Error (RMSE) were used in the validation of the IDF formulation. The MAE, RMSE NSE and were 33.9209, 5.8241, 0.9599 and 0.9634 which explains the model to be reliable to prediction.