An Evaluation of Some Methods of Determining Storage Yield Relationships for Impounding Reservoirs

Twelve methods of storage yield estimation available in the hydrological literature are identified. Eight of these are then selected for use in a comparative study where the objective is to select those methods with least bias and standard error. A time-series model is used to generate a population of 3000 years of synthetic flow data for one set of Irish conditions. The true population storage volume for each level of yield and return period is obtained by counting, and the storage estimates obtained using the eight selected methods are compared with the population volume on the basis of bias and standard error. The Modified Gould and Behaviour Analysis Methods were found to have least bias and the lowest standard error. These methods are therefore recommended for use, in conjunction with simulation methods of investigating storage requirements, for Irish and similar climatic conditions.