Study On The Analysis Of Urban Rainstorm Runoff Regulation Mode

With the development of the social economy and accelerating urbanization, the increasing impervious area cuts off water infiltration channel, causing great loss of water resources, increased storm peak, earlier peak time, which result in poor drainage and stagnant water in local region that make people's lives great inconvenient.The old city sewer drainage could not solve the city drainage problems, and the urban rainwater runoff generates far beyond the original design capacity.Therefore, aiming at urban storm runoff's mechanism and process, combined with Xi'an local weather, climate and geographical conditions, several ways of the heavy rain runoff regulation are researched and compared in this article. By applying the urban storm water management model (SWMM) to these two measures, flooding slabs and low elevation greenbelt, in a residential community in the northern suburbs of Xi'an, the author has made analysis of changes in peak flow discharge of the main section, and led optimization of the size of rainwater harvesting storage tank's and economic benefits, providing reference for the similar engineering calculation. In this article, we focused on three aspects for intensive study.First of all, the process of runoff generation and affluxion of city surface rainwater is analyzed. The deducing and calculation of three different surface runoff mechanism is conducted; According to the calculated results, runoff yield is divided into impervious area, impervious area and mixed area; And based on the appropriate method of storm breakage, try to acquire the formulation of urban surface runoff and urban surface's the net rainfall process line through computing.According to the method to solve Saint-Venant equations, the classical slope theory of the uniform rainfall intensity is applied to net rain intensity calculation of the non-uniform flow by the method of rating superposition, then analyses various factors on the River confluence and briefly presents a variety of urban runoff simulation models.Furthermore, in order to observe and study the effects of different measures on flood prevention and rainwater resources utilization, the urban storm water management model (SWMM) is used to calculate and analyze the changes in peak flow discharge of the main section in these two measures, flooding slabs and low elevation greenbelt, in a residential community in the northern suburbs of Xi'an.Finally, for the regulative utility of rainwater, a rainwater regional utilization system is built to analyse and research the application of rainwater storage tanks in the local area. Based on statistics of rainfall data for years, the rainwater storage tank size and design rainfalls is presented for representative urban, taking the healthy water cycle and run-off emission into account. It can provide a useful reference for a similar projects design and construction.