Impact of precipitation data density and duration on simulated flow dynamics and implications for ecohydrological modelling of semi-arid catchments of Southern Africa

•Precipitation station sensitivity analysis to determine important stations.•Regional sensitivity analysis of distributed J2000 model.•Identify precipitation stations which impact simulated peak and low flows.•Identify sub-basins important for overall runoff generation.•Optimized precipitation station weights can account for microclimates.