Analysis of Design Rainstorm Hydrograph Based on Asymmetrical Extreme Value Copula

In this paper,the maximum 1-hour rainfall( rain peak),the maximum 6-hour rainfall and the maximum 24-hour rainfall in the Caojiang River basin from 1967 to 2013 were taken as samples. The typical typhoon rainstorm hydrograph of joint distribution of rainfall in three periods was constructed based on the asymmetric Archimedean Gumbel-Hougaard extreme value Copula. The main conclusions were as follows:( 1) the design rainstorm value in the Caojiang River basin calculated by using the joint distribution of rainfall in three periods was larger than the design rainstorm value of the joint distribution in two periods and that of a single period. The design rainstorm process hydrograph amplified at the same frequency had the optimal overall effect,which provided a new idea and method for studying the design rainfall patterns.( 2) According to the maximum 24-hour rainfall,the risk rate of the multi-peak rainstorm process that the main peak was in the back was the highest,and the constructed typical design rainstorm process hydrograph was the most representative.( 3) " OR" joint return period of rainfall combination in three periods as the design criteria of a watershed was applicable to responding to the risk of rainfall and flood in this watershed.

Study on Design Rainstorm Profile in Liuzhou City：Chicago Method

The design rainstorm profile is the basis of scientifically and rationally planning and designing urban drainage system, which can provide scientific theoretical basis and accurate design parameters for municipal construction, water and planning departments. In this paper, the minute-minute rainfall process data at Liuzhou National Meteorological Observation Station from 1975 to 2014 were used. Chicago method was used to analyze and study design rainstorm profile in urban district of Liuzhou, and the profiles of the rainfalls lasting for 30 , 60 , 90, 120, 150, and 180 min were obtained. The results showed that the design rainstorm profile with the same duration in each reappearance period was consistent in Liuzhou, and short-time rainfall profile roughly showed single-peak shape. The peak of each short-time design rainstorm profile was almost in 1/3 part of the whole rainfall process, and the intensity of rainfall increased with the prolonging of the recurrence period. The rainfall intensity at the peak in the same reproducing period showed 11 decrease - increase -decrease＂ as the duration increased, and the peak value of rainfall lasting for 120 min was the maximum.

Urban flood inundation and damage assessment based on numerical simulations of design rainstorms with different characteristics

In the context of global climate change and urbanization,urban flooding is an important type of natural disaster that affects urban development,especially in China,which is experiencing rapid urbanization.In the past 10 years,urban flooding events have caused huge disaster losses in Chinese cities.This has resulted in significant negative effects on the urban infrastructure,socioeconomic systems,and urban residents,thus causing widespread concern.Studies have confirmed the change in extreme rainstorms is due to the changing environments in many cities globally.Conducting studies on the impact of these rainstorms with different characteristics for urban flooding is valuable for coping with unfavorable situations.In addition,numerical simulations provide an economical and viable means to perform these studies.This paper presents a numerical model of Xiamen Island in China.Simulations were conducted for 12 design rainstorm events with different return periods,rain patterns,and durations.The results indicate that,in the case of an equal rainfall amount,the rainfall intensity is the key factor that affects the inundated area,depth,and damages.However,the rainfall intensity is not the only determining factor;the rainfall pattern also affects the inundations.In regard to the rainfall pattern,a higher rainfall peak coefficient usually leads to severe urban inundation and damage.As a result,the lag time would be shorter,which may further exacerbate the impact of urban flood disasters.The results of this study provide insights into managing flood risks,developing urban flood prevention strategies,and designing flood prevention measures.