Agricultural Drainage Water Assessment for Possible Reuse: A Case Study from Pandamatenga Commercial Arable Farms in Botswana

Abstract

This study set out to assess the quality of water in the drainage channel located in the northern plain of the Pandamatenga Commercial Arable farms in Botswana for possible agricultural reuse. This was achieved by analysing the physical, microbiological and chemical parameters of sampled Agricultural Drainage Water along the drainage channel. The results obtained from the Agricultural Drainage Water quality analysis were used in an Irrigation Water Quality Index model to assess the possibility of reusing the water. The Irrigation Water Quality Index results from the study revealed that the values computed from the five parameters of Sodium Adsorption Ratio, Electrical Conductivity, Sodium, Chloride and Hydrogen carbonate, ninety five percent of the samples fell within the “severe restriction” category, five percent of the samples fell under the “moderate restriction” and no samples belonged to the “no restriction” category. The low levels of Electrical Conductivity and Sodium Adsorption Ratio detected in the water samples during the study period indicated a mineral imbalance, hence making the Agricultural Drainage Water unsuitable for direct reuse. Therefore, using this Agricultural Drainage Water will require mixing it in proper ratios with groundwater to improve its quality for reusability during irrigation. If the Drainage Water is reused, this will have potential to increase the water for irrigation in semi-arid Botswana.