Design Storm Pattern Analysis In The City Of Shenzhen

Urban rainfall drainage system is an important infrastructure for modern cities.With the development of Shenzhen,the drainage system is also constantly improving.However,there is still a situation where the drainage standards and urbanization progress are inconsistent.There will be a waterlogging when rainfall formation water can not discharge in time.coupled with the increase in extreme weather in recent years,the short duration of high-intensity rainstorms has caused serious water accumulation in some sections of the city and low-lying areas such as overpasses.Therefore,the urban drainage system is attracting more and more attention.The study of the planning,design,and management of urban stormwater drainage systems and the formulation of more stringent standards for urban development are issues that need to be addressed urgently.At present,Shenzhen City's urban and suburban design storm patterns are based on the24-hour rain pattern of the "Guangdong Province Storm Runoff Checking Chart Manual".The 1-hour 24-hour rain pattern meets the design requirements for urban and suburban water conservancy projects of Shenzhen in the last decade or so.However,the minimum time period is 1 hour,which cannot meet the requirement of a minimum time period of 5 minutes for the municipal drainage design.This study is based on the continuous rainfall data of Shenzhen in the past 51 years,using the annual maximum method to select samples,through the P-III distribution model to draw the design rainfall of different rainfall duration in different return periods.The short-duration rain type is based on the existing storm intensity formula,using the Chicago law rain model to estimate the short duration rain type in Shenzhen at a time interval of 2 hours and 1 minute,and a 5-minute interval.The long-term rain type uses the same frequency analysis method to calculate the 24-hour design rainstorm type in Shenzhen.This study summarized the actual rainfall process and established urban rainstorms in Shenzhen City.Two types of rainfall were used for the design of urban drainage pipe and waterlogging facilities design respectively in the“Shenzhen Urban Drainage and Waterlogging Prevention Comprehensive Plan”,which provides strong support for the full use of hydraulic models in planning.