REGIONALIZATION OF DAILY FLOW CHARACTERISTICS IN PART OF THE EASTERN CAPE, SOUTH-AFRICA

A method is described that allows long-term 1-day annual and seasonal flow duration curves at any ungauged location in one of the drainage r egions of South Africa to be established. The method is based on norma lization of observed flow duration curves by a long-term mean daily fl ow and subsequent averaging of normalized ordinates of the curves. The estimate of mean daily discharge for an ungauged site is obtained usi ng the information from the existing national data base of flow charac teristics. The established set of flow duration curves at a site is fu rther translated into actual daily streamflow time series using a simp le nonlinear spatial interpolation technique.