Emmanuel Salifu^1,, Shedrach Onum Enokela¹

Rising water tables is one of the major problems affecting irrigation and agriculture in general, hence, regular investigation of the trend of groundwater fluctuation especially within 'fadama' lands is necessary to forestall incidences of flooding and salinization which are harmful to arable soils. Groundwater fluctuation was monitored between February and September, using chalk-dusted graduated steel tapes at five (5) piezometric locations in a small-scale fadama irrigation farm, in the Niger-Benue Confluence, Lokoja-Nigeria. It was observed that the mean monthly depth of water table fluctuates between 2.03m bgl and 0.022m agl in the period under review. Statistical analysis of data collected show that the trend of fluctuation obeys a third order hyperbolic function (with R²= 0.98). Findings imply that the land is critically waterlogged between February and September, with rainfall depth significantly affecting groundwater fluctuation, and will be prone to salinity hazard overtime. There may be need to carry out further investigations on the hydrological characteristics such as hydraulic conductivity, infiltration and evapotranspiration for the area; these may inform the need to design appropriate measures for the water resources management in this area; such as installation of drainage structures/facilities to check the flooding and/or drilling of more shallow tubewells for irrigation purposes in months of less rainfall.

groundwater fluctuation, fadama, Niger-Benue confluence, salinization