Incorporating physical characteristics of processes in hydrological analysis is one of the focuses of hydrological field. A scale model is introduced and its merits and limitations in calculating design rainfall depths

compared to traditional frequency analysis (direct method)

are analyzed in this paper. The data were collected from rainfall gauges of Hong Kong New Territory. It is found that the scale model is applicable for rainfall durations of 120

360

720 and 1 440 min. The calculated rainfall depths are smaller than those from the direct method. The differences between rainfall depths increase with return periods. It is concluded that the scale model is more reasonable than traditional frequency analysis and can be used as an alternative or complement to design rainfall depth calculation.