Review on urban design rainstorm

Abstract

Design rainstorm is the basis of calculating design floods for the design of urban hydraulic infrastructures and many other fundamental facilities. It has significant influence on the planning scale and investment of urban drainage engineering. Without a wise selection of the design rainstorm pattern, it is impossible to guarantee the safety and economic effectiveness of designed urban drainage infrastructures regardless of simulation accuracy or any remarkable techniques. In recent years, cities in China have suffered from severe urban floods, so urban drainage system construction and comprehensive underground corridor building are two enormous and vital task in the near future. In addition, urban construction in China (especially water-related projects aiming at urban areas, such as sponge city project that China is currently implementing nationwide, drainage pipe systems construction and underground reservoir installation) has put forward new challenges to and raised higher requirements for urban hydrological theory and mechanism research, including urban design rainstorm research. In this context, it is highly necessary to systematically summarize the theory and research methods of domestic and foreign urban design rainstorms, to summarize the existing key problems, to clarify the main aspects of the nodus, to discuss and propose the development direction of urban design rainstorm researches. Researches on urban design rainstorms have been conducted both in China and abroad. In the past 30 years, urban design rainstorm research in China has made great progress and important changes, and the theory and research methods of urban design rainstorms in the world become more consummate. Through methods of literature research and analysis, researches all around the world on urban design rainstorm have been sorted and classified, and the theories of urban design rainstorm are systematically reviewed after screening and comparison. The main content of this paper contains summary on sampling methods, frequency analysis, storm formulas and spatial-temporal disaggregation methods of urban design rainstorm. The mainstream methods are summarized and compared; their advantages and disadvantages are analyzed, and the main problems existing are discussed. Finally, combined with the results of literature review, the future research direction of urban design rainstorm researches is proposed. The study of urban design rainstorm in the future may pay more attention to the following aspects: (1) illustrating principles and control methods of error generation in each step of forming an urban design rainstorm, and searching for the link between various aspects during urban design rainstorm forming, to find the optimal matching method between those aspects; (2) conducting urban design rainstorm studies that cover the whole ″rainstorm sampling-frequency analysis-intensity formula-spatio/temporal disaggregation″ process, searching for regional analysis methods based on linear moment (L-moment), and developing tentative national IDF curves as well as popularizing their usage; (3) enhancing the study on evolution laws and characteristics of short-duration urban storms under changing environments, evaluating the impacts of urbanization and climate change on urban rainfall characteristics, and analyzing how urban design rainstorms should reform in response. This paper provides a wide range of perspectives on the study of rainstorms in China and even in the world, and provides important guidance for future research on urban design rainstorm.