Study On Restoration Of River Wetland In North District Of Fuzhou Under Urban Redevelopment

Channelization is a common pattern of river regulation in cities.Although it has many advantages,it seriously damages the ecological properties of urban rivers,and is the main factor leading to the deterioration of urban river water environment.In recent years,the Northern District of Fuzhou has faced a serious problem of Water quality problems.Over the past 20 years,Fuzhou has carried out a series of comprehensive river regulation measures,such as revetment repair,pollution interception,desilting,landscape construction and so on.However,artificial regulation has not fundamentally improved the self-purification ability of inland river water.Once the manual control is stopped,the water quality will deteriorate rapidly.Artificial methods of regulation are not sustainable in the long run.Only by eliminating the channelization as a whole can the river water quality be fundamentally improved.Channelization is not only the model of Urban River section,but also the model of urban construction land.The mode of urban land use must be adjusted so as to fundamentally change the way of river regulation in channelized river.Therefore,the urban redevelopment is a good opportunity.In the urban redevelopment,through adjusting the land function,the Green Space and the river union,forms the functional wetland superiority pattern.After that,the Natural River leading into the city boundary will no longer be channelized,and the channelized river will be restored by technical means to the wetland.The urban redevelopment was carried out step by step in different areas.Urban River wetland restoration can not be accomplished overnight.The adjustment of urban land use should be uniformly planned and carried out in stages.For River Rehabilitation,priority should be given to the upper reaches and key river sections,and the proportion of Ecological River sections should be gradually expanded through urban renewal.Finally,it not only improves the water environment of the city,but also promotes the development of the city landscape and realizes the dual restoration of the city.The main processes of the study were:(1)investigate the present situation of river wetland and urban redevelopment in North District of Fuzhou,analyze the cause of water quality deterioration,and find out the relationship between the old city reconstruction and river wetland restoration;(2)Yangxia River Catchment is a typical example.Based on ArcGIS software,runoff and catchment analysis was carried out and wetland network was constructed.(3)According to the development intensity,the water gathering units are divided into three categories: high development intensity,medium development intensity and low development intensity.On this basis,taking the water gathering units as the urban redevelopment planning area,three types of old city reconstruction areas are obtained.The restoration targets of river wetlands in different types of regions are also established.(4)on the basis of the wetland network in the catchment area,the planning and design of three types of old city reconstruction areas are carried out respectively.The restoration models of river wetlands with different development intensity were summarized.(5)integrating various types of regional planning,the planning scheme of Yangxia River catchment based on the theory of functional wetland was obtained.Through the comparison,the indirect verification function wetland idea intervenes the city river water quality control to be effective.The new plan can not only guarantee the original development intensity,but also improve the regional ecological structure,and provide conditions for the restoration of channelized river wetlands.Finally,the paper summarizes the restoration methods of river wetland under the background of Old City reconstruction from macro,Meso and micro aspects.