Study On The Effect Of Green Space In Changsha City On Storm-water Relief

The progress of society in the developing era has produced more convenient city life. However, at the same time, many problems existing in cities becomes more and more obvious as the time goes, among which the rainstorm waterlogging poses the greatest threat to inland cities. Based on the collection of the results of the past researches on rainstorm waterlogging in cities, investigations on the current condition of rainstorm waterlogging in Changsha city have been conducted by using methods of literature research, field survey, spatial analogy and the comprehensive study. On this basis, a research on city waterlogging relief has been conducted to provide a reference for the construction of cities in the same type.This paper studies from the following aspects. The investigations of the current condition of the rainstorm waterlogging in Changsha expose thirty-four places susceptible to this problem. And then an analyzation shows the four reasons causing waterlogging:the extreme weather, the excessive hardening of the city ground, the converting of lowlands into construction lands in the city, and the backward underground drainage system. Further more, after a comparison with the case that Fushou ditch in Ganzhou, Jiangxi province has not been waterlogged for several hundred years, a pro-harmony thinking way is established to explore the methods to alleviate the waterlogging by the aid of the ecological, social and landscape means.The concept of utilizing rainwater as resource is put forward to change the traditional thought that the rainwater must be drained as soon as possible for it is a disaster rather than a resource. The green fields in city increases the permeability of rainwater and the ones in lowlands storing rainwater can be a source container for the irrigation afterwards, forming a model to eliminate waterlogging and transform the disaster into resource for the city. On this basis, the rainwater relief measures have been discussed and the measure taking advantage of the green fields is deemed as the best way in this respect. What’s more, the principles for the layout of green space are proposed, namely, making overall arrangements with a reasonable and balanced layout, bearing diversity in function with priority, guaranteeing the security in plant selection, and being beautiful and practical.In the last part of the paper, taking the center district of Changsha as an example, it focuses on the green space planning, the layout of traditional ponds, and the relationship between the distribution of green fields and waterlogging places. The designing of layout for the green space is put forward to deal with rainstorm waterlogging in center district of Changsha, namely, to use different forms of green fields to relief the problems brought by waterlogging.