Temporal Water Balance Analysis in Different Climatic Scenarios in Oyo State, Nigeria

The study was conducted to examine water availability in different climatic scenarios in Oyo State. The data used comprised of rainfall and temperature records. The spans of the data used vary from one station to the other: 38-year data for Ibadan and 37-year for Ogbomoso stations, both collected from NIMET Office, Ilorin while 11-year also collected from the Office of Oyo State Agricultural Development Programme (OYSADEP) Headquarters at Shaki were available for Shaki Station. Evapotranspiration data for the three stations were empirically generated while water balance model was computed using MATLAB R2007a version in order to determine the respective water availability and the regression analysis was used to determine rainfall trends. The results showed that rainfall amounts vary from year to year and also increasing trends in the three stations over the period examined. It was also discovered that in all the periods investigated across the stations, Ibadan has 81.58%, Shaki, 81.81% and Ogbomoso, 56.80% as wet years indicating that there is abundant water resources in Oyo State. It is recommended that strategies be put in place to exploit excess rainwater for various purposes especially by increasing the capacity of water reservoirs and dams across the State for development of pipe borne water network and also, for irrigation farming during dry spells. Further investigation is recommended on water balance and its implications for agricultural practice in the study area.