Design and Construction of Clear Wash Bores and Tubewells for Irrigation Purposes in thwe Fadama Area of Gakpan, Kwara State, Nigeria

Abstract

Gakpan fadama is an extensive flood plan of over 18,000 hectares of land occasioned by alluvium deposits with a potential for both small and large scale irrigation development on the bank of River Niger in Patigi Local Government Area of Kwara State. Alternative well designs and construction methods for ground water abstraction from fadama aquifers were investigated. Test and analysis of results for Soil particle Size distribution, infiltration; yield (pumping and recovery) tests as well as recharge rates ware conducted. Results showed that effect of well diameter of 750 mm (75cm) on recharge was very minimal (11.15cm/hr). Permeability measurements of 9.74cm/hr indicated that surface water contributes immensely in the recharge of the aquifer. Transmissivity of 1265.09m 3 /day and storativity of 7.91x10-3 was calculated. The results of the aquifer and the textural class of the Soil (silty-clay-loam) shows yield potentials of the wash bore .However, high variability in Soil Size Fractions were, revealed in the Practical Size Distribution Analysis, this is an indication of likely variation in permeability and consequently, well recharge ratee within the fadama. Therefore, a clear water wash bore is feasible in Gapkan fadama area.