Assessment of Rainfall-Baseflow Relationship in Bua River Catchment, Malawi

This study mapped groundwater recharge zones and established the rainfall-baseflow relationship in the Bua River Catchment in Malawi between 1985 and 2007. The study used ArcGIS 10.3.1 using the Weighted Overlay tool for groundwater mapping. The two-parameter Recursive Digital Filter method (Eckhardt) was adopted in the baseflow separation. The non-parametric Mann-Kendall (MK) statistical test was used to identify if the Baseflow was increasing or decreasing. The baseflow component's trend was analysed using the cross-correlation coefficient between baseflow and rainfall. The results suggest that.1. Groundwater flows in the basin were in the general west-to-east direction.2. The water table elevation (rise) was found to be in the southwest of the basin.3. Other stations, including those on the Lakeshore, correlated negatively during the rainfall season (The cross-correlation was checked at a 12-time lag in the smoothed data of annual rainfall and baseflow).Therefore, these findings suggest that rainfall has little implication for the baseflow components in the Bua River Catchment. Rather, it is an interplay of different factors that influence baseflow components in the basin.

Pagina's: 44, Paperback, Eliva Press