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

Abstract

Climate change has led to drought and flood recurrence and erratic changes in the meteorological parameters in this fragment of the globe, leading to damage of assets, deaths, food shortages, and more. A crucial tool in water resources engineering is predicting the Rainfall Intensity-Duration-Frequency (IDF) relationship. The goal of this study is to establish the rainfall intensity-duration-frequency model and curves for Benin City, Edo State, Nigeria. The Nigeria Meteorological Agency (NIMET) provided 30 years of rainfall data, which was sorted for frequency analysis. This work aims to establish a mathematical IDF model for the prediction of rainfall intensity for variable rainfall durations and return periods and to validate the model using statistical test statistic for its justification. The IDF model was developed using storm durations of 5, 10, 30, 60, 120, 240, 360, and 720 minutes, as well as the corresponding frequency of recurrence. The IDF curves for this investigation were created using the generalized empirical technique. 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 25.9975, 40.80850736, 0.988154265, and 0.980978124 which explains the model to be trustworthy for approximation.