Assessment of the Quality of Shallow Groundwater for Irrigation in the Atankwidi Sub-Basin of the White Volta Basin, Ghana

Abstract

The potential use of shallow groundwater for small-scale dry season irrigation is a key issue for irrigation development in the arid zone of Ghana. Farmers within the Atankwidi sub-basin of the White Volta Basin are increasingly adopting groundwater as a source of irrigation water due to the unavailability of surface water during the dry season. However the quality of the groundwater and its suitability for irrigation is not known, hence the need to assess the quality and its suitability in order to ensure sustainability in the application and possible expansion of groundwater irrigation in the area. Two main water types (Ca-Mg-HCO₃ and Na-Mg-Ca-HCO₃) have been determined using the Piper diagram. The relative abundance of cations in the groundwater was found to be in the decreasing order of Na⁺ > Ca²⁺ > K⁺ > Mg²⁺ > Fe²⁺. Similarly, that of anions was found to have a decreasing order of HCO₃^- > SO₄^2- > Cl^- > PO₄^2- > NO₃^- > F^-. Groundwater in the area had low SAR and low to medium salinity hazard. However, magnesium hazard and alkalinity problems are likely to limit its use for irrigation.

Keywords: Shallow Groundwater, Hydrochemical facies, Irrigation Water Quality.