ASSESSING THE ADEQUACY OF CATCHMENT STREAMFLOW YIELD ESTIMATES

Rainfall-runoff models are frequently used by hydrologists to estimate runoff from rainfall and climate data, with the model adequacy assess ed by comparing the level of agreement between flows simulated by the model and the recorded flows. This paper describes simple methods (vis ual plots, statistical parameters and dimensionless coefficients) whic h are commonly used to compare estimated and recorded streamflow time series and discusses their advantages and limitations. Results of a su rvey conducted to ascertain the required quality of flow estimates bef ore they are considered to be satisfactory, as well as to identify pre ferred methods used by hydrologists in Australia to determine the adeq uacy of streamflow estimates, are also discussed in this paper. Inform ation from the survey is also used to suggest objective criteria based on dimensionless coefficients that can be used as guides in assessing the adequacy of flows estimated by rainfall-runoff models. In particu lar, the coefficient of efficiency is a very useful indicator in asses sing model adequacy.