Prediction of Hydraulic Characteristics of Aquifer and Availability of Water Supply for Irrigation Farming in Basement Complex Terrain, in Part of Ilorin Sheet North-Central Nigeria

Abstract

An investigation to predict ground water supply for irrigation farming around Amodu-Irapa was carried out based on data from pre-drilling, aquifer testing for six (6) exploratory wells. Cooper_Jacob non-equilibrium graphical methods were used to interpret the constant rate and recovery data to determine the hydraulic properties. The discharge values range from 1.9 l/sec to 2.5 l/s while hydraulic conductivities and transmissivities range from 0.2m/day to 2m/day and 12m2/day to 36 l2m2/day respectively, with average specific capacity of 2m3/sec/m. the average yield per hour is 100l/hr and draw down of 15m. The six wells will provide a total daily abstraction of 1600.8m3 based on 16hour daily pumping schedule. The hydraulic characterization indicated an average of 16hrs of pumping per day with mean drawdown of 31.8m, indicating 63.6% of the mean aquifer thickness but, the quartzo-pegmatite exhibited highest transmissivity and aquifer thickness value of 316.8m3 daily pumping at maximum drawdown of 31.6% of the aquifer thickness and can supply water for 5 ha paddy field, should be targeted during geophysical survey. Pumping in excess of 16 hours a day should be avoided without monitoring the pumping water levels to assess the groundwater resources more fully.