Aquifers Hydraulic Parameters Measurement and Analysis by Pumping Test

Hydrogeological properties measurements through pumping or slug test is an imperative method of determining the productivity of an aquifer for effective sustainability and development. Therefore groundwater potential evaluation using pumping test was carried out on thirty six boreholes, straddling different geologic units in Southern parts of Ondo State, Nigeria. This was done in order to estimate the transmissivity and hydraulic conductivity of the overburden aquifers. The pumping test involved a 1.0-hp submersible pump with a check valve and a 19-mm diameter discharge line. The static water levels measured range between 1.2 – 30.5 m, and an average of 11.9 m. The static water level was higher in sandstone derived aquifers than shale, granite, gneiss or migmatite, with an associated low drawdowns less than 2 m. The values of hydraulic conductivity estimated in the area vary from 0.0797 (Ile Oluji) to 65.2493 m/d (Ilaje/Ese Odo/Igbekebo), and an average of 6.25 m/d. The transmissivity values range between 1.6183 – 652.4928 m2/d. The recorded specific yield of the aquifers across the study area shows predominant range of 0 – 100 m3/d. This range of values generally indicate a non-prolific aquifers, as the mean value obtained is less than 200 m3/d required for domestic usage based on groundwater usage survey carried out in the study area. The findings of the study shows a fairly homogeneous hydraulic properties, except the southern part which is characterized by high yield capacity, transmissivity, hydraulic conductivity, and considerable aquifer thickness (greater than 25 m) with a steady/high drawdown. Consequently, favourable areas for future groundwater exploitation/development is the southern parts which embraced Erinje, Okitipupa, Ilaje/Ese Odo