Assessing the Potential of Artificial Groundwater Recharge: Case Study of Palla Road Wellfields, Botswana

Abstract

A feasibility study on the assessment of managed aquifer recharge in the Palla Road wellfields which are situated in the Bonwapitse and Serorome Catchment area, Botswana was conducted. Botswana is categorized with a semi-arid climate and most of the country’s anthropogenic activities are highly dependent on groundwater which can lead to over abstraction and thus depleting the aquifers. Many countries, including Botswana need to explore several water resources in order to augment the available surface water resources and thus overcome the imbalance between water supply and water demand; one of the alternatives being Managed aquifer recharge (MAR). This research is based on spatial observations using the soil water balance and QSWAT + models to identify and assess the potential areas suitable for managed aquifer recharge in Palla Road wellfields. The following datasets were used as input files for the models: land cover, flow direction, hydrologic soil group, the soil available water capacity and climate data. The models were ran using climate data for a period of eleven years (2008-2019) respectively and the groundwater recharge was found to be prominent in three (3) years viz; 2008, 2012 and 2016 respectively in the soil water balance model. The suitable groundwater recharge zones were found to be in the central and south eastern region of the Bonwapitse and Serorome catchment area for both models. High annual groundwater recharge values, high precipitation and low values of evapotranspiration were observed in the region when using the QSWAT + model. MAR has been found to increase groundwater recharge and reduces the deficit in water supply. Therefore, implementing MAR in Botswana serves as a basis to diversify and improve the current available water resources.