“Rainfall Harvesting, a Sustainable Water ManagementAlternative for Food Security in Nigeria

Nigeria with her expanse of land is greatly endowed with potentials of first class food producing nation. Weather information of thirty six states including the Federal Capital Territory: Altitude (AT), population density (PD), average annual rainfall (AR), land mass (LM), latitudes (LT), longitudes (LG), relative humidity (RH), maximum and minimum temperatures (MX, MN) and average daily wind run (WR) were collated, processed and analyzed. Isotherm, isobaths, isohyetal, isotach and isohume maps were constructed. Weighed rainfall of the states was evaluated. Frequency of exceedence based on frequency analysis model was determined. Empirical model generated by NIHORT using 28m2 roof surface area obtained through daily rainfall was used to evaluate the rainfall harvesting potentials of thirty six states of Nigeria including federal capital territory (FCT). Exceedance frequency was highest for Katsina with average annual rainfall of 552mm , altitude 464m, latitude 12o12’N, longitude 7o30’E and population density, 160.3/km2, while Minna recorded the highest weighted rainfall of 116.2mm with average annual rainfall of 1400mm, altitude 299m, latitude 10o00’N, longitude 6o0’E, showing the highest potentials for rainfall harvesting at 129.3km3, though 18th in ranking respect to the actual amount expected based on the average annual rainfall and 28m2 roof surface area.