Development of Rainfall Intensity-Duration-Frequency (IDF) Curve for Abuja, Nigeria

Urban flooding is a major social and economic problem of any nation. The social implication is attributed to loss of lives and property, unwanted displacement and emotional disturbance attached. While that of economic problem is the cost of mitigation of flood and the aftermath solution. Thus, storm water drainage is part of essential modern city infrastructure. The need for proper analysis and design of drainages and other road water facilities cannot be overemphasized. To achieve this, critical analysis of available rainfall data, which is a key input, is required. A 35 years daily rainfall data were obtained from NIMET, from which the analysis was carried out using frequency method. The output generated are presented in graphical forms and model. Ultimately, an IDF curve generated, depicts Abuja rainfall pattern from which a 3-parameter model equation, I = 37Tr0.2 (t + 0.1)−0.9 was formulated. This is site or location specific. The curve and/or the formulated model can be adopted to determine rainfall intensity of Abuja city if the rainfall duration and return period are predictable.