Study of the natural rainstorm moving regularity method for hyetograph design

Using minute-based precipitation data for the period of 1961–2016 from the National Basic Weather Station of Shapingba, the main urban region of Chongqing, China, and by combining the concept of moving sampling with the natural rainstorm process, a novel sampling technique called natural rainstorm moving sampling was designed. A novel design hyetograph method, the natural rainstorm moving regularity (NRMR) method, was derived from this sampling technique for hyetograph design. The samples obtained through natural rainstorm moving sampling were compared with those obtained from the annual maximum method (a commonly used sampling method) and with actual waterlogging records. Fuzzy identification verified the rationality of the NRMR method in determining the peak shape. In addition, the NRMR method, the Pilgrim and Cordery (PC) method, the Chicago method, and the common-frequency method were compared; the results showed that natural rainstorm moving sampling is a reasonable sampling approach, and it is simpler and more applicable than the other methods. The results of this study provide a scientific basis and reference for urban drainage design to reduce urban waterlogging disasters in Chongqing. At present, the results have been applied in the formulation of the rainstorm intensity and the design of a rainstorm hyetograph in Chongqing.