Characterisation and water resource assessment of Shashani sand river, Matabeleland South, Zimbabwe

Abstract

Sand rivers are a common water source throughout the dry regions of the world. However, there is limited literature with regards to their storage capacity and potential water supply. The objective of this study was to characterise the Shashani sand river and assess its potential for water supply, by. estimating aquifer volume and recharge. Sand depth was determined by mechanical probing, and surface area of the river by remote sensing, enabling calculation of aquifer volume. Storage capacity was estimated by multiplying the volume by the porosity, and climatic data used to determine potential recharge into the Shashani sand river, for typical dry, wet and normal years. The Soil Conservation Service (SCS) curve number method was used to determine runoff into Shashani River. The volume of the aquifer was estimated at 23 900 000 m³. The potential recharge from Shashani sand river before abstraction and water losses was 843 831 880 m³ for a wet year, 227 662 070 m³ for a dry year and 550 450 900 m³ for a normal year. The study showed that Shashani sand river has a very high water storage capacity and has the potential to supply water to farmers for domestic use and irrigation of community gardens throughout the year. Findings from this study are useful to water authorities for water budgeting and agricultural planning. Further studies are required to investigate the sustainable abstraction rate. This study will inform the procedures used in the characterisation of sand rivers for agricultural usage; the approach used is lower in cost than others used in the characterisation of resources in the region. The chosen methodology can be applied in the quantification of other sand rivers globally.