The Power Function for Representing the Reservoir Rating Curve: Morphological Meaning and Suitability for Dam Breach Modelling

In this paper the authors demonstrate that the simple power function gives a good description of the reservoir morphology. This function proved to be suitable for application on 97 reservoirs taken from three different geographical regions in the world. The power function is suitable to obtain an accurate fitting of the reservoir rating curve using a very limited number of surveyed elevations and volumes or areas. In particular it is shown that two points are enough for a good fitting of the curve, or even only one if volume and surface for an elevation close to normal or maximum pool are both available. The results obtained for dam breach calculations using this equation, have the same quality of those achieved using the elevation-volume table. The paper stresses that the exponent of power equation can be expressed by a formula which has a precise morphological meaning, as it represents the ratio between the volume which the reservoir would have if it were a cylinder with its base area and height equal to the respective maximum values of the actual reservoir, and the real volume of the reservoir.