Constrained scaling approach for design rainfall estimation

Abstract

Applications of scale-invariant ideas have been one of the most exciting areas of research in hydrology. The past studies showed positive evidences regarding the scale-invariant behavior in hydrological processes. In this paper, the scale-invariant approach found its way in frequency analysis for design rainfall depth estimation. In practice, intersections among design rainfalls for different durations under a same return period often occurs, which may provide wrong information in engineering planning and design. Furthermore, frequency analysis is currently regarded as inappropriate due to its lack of physical principles. In this paper, the scale-invariant approach is proposed, coupled with a constrained regression analysis, to make corrections on the possible intersections. The aim of this paper is to investigate the feasibility of applying such approach to deal with the intersection problem. A Hong Kong case study is used to demonstrate the application. The results are interpreted as more reasonable than those based on frequency analysis and are capable of providing substantial support for engineering planning, design, and management purpose when only a small sample of data are available.