SUMMARY
The March 1988 flood is the best-studied flood that the Orange River has experienced, as far as both its devastating effects and its unusual character are concerned. This paper investigates the characteristics of the flood and compares the findings with those for previous floods. It is shown that the runoff for March 1988 probably has an exceedance value of the order of 1 in 100 to 200 years, although the annual runoff for the 1987/1988 hydrological year is equivalent to only about a 1 in 10 to 15-year event. An account is given of flow characteristics in the mouth of the Orange during the flood, as well as of associated bank erosion rates and scour under the Ernest Oppenheimer bridge.