OPTIMAL AQUIFER WITHDRAWAL MODEL FOR IRRIGATION SCHEDULE IN BIDA BASIN, NIGER STATE, NIGERIA

Abstract

This research work stemed from the challenges of crop water need within Bida basin. It is focused on three identified problems of irrigation farming. These are the quantity of groundwater available for irrigation; optimum quantity of water to be drawn from well during the dry season as well as crop water need. The mass balance equation was solved and use to determine the groundwater level. The Lagrange multiplier method was used in estimating the optimum quantity of water to be drawn from the well during the dry season while computational method was used to solve energy balance equation and Pen – Monteith equation to determine estimated crop water needs using rice and soya beans as samples. The results obtained for the estimation of the quantity of the groundwater show that there is considerable amount of water (6 3 27.19 10 ft  , 6 3 21.81 10 ft and 6 3 5.94 10 ft  ) available for irrigation. For groundwater withdrawal the results show that moderate amount of water is drawn from the wells in each of the study area while the results obtained for estimated crop water needs conformed to crop water requirement estimated under standard conditions these are 5960.5mm in Mokwa; 2326mm in Bida and 5584.22mm in Lapai. This research project provides useful information to farmers on how to make proper planning for irrigation farming in order to achieve optimal crop yield.