Ecological Restoration Design Of Zhoujiagang Stream Of Maoli Lake In Jinshi City

With the rapid development of society and economy,the problems facing ecological water environment are becoming increasingly grave.In the recent years,due to the combined influence of natural and many unreasonable human factors,Maolihu lake is faced with the worsening soil and water loss,and increasingly severe water resources,which have wreaked havoc to the regional ecological environment.So the urgent task of ecological restoration stares us in the face.Zhoujiagang watershed is one of the eight permanent streams in the Maolihu lake basin.So the water quality of the small watershed directly affects the overall water quality of the Maolihu lake basin.From the measured data,Zhoujiagang watershed is faced with the increasingly severe problems of soil and water loss,water pollution and vegetation degradation and others.In the long run,the ecological environment of the basin will be further damaged.As a result,designers are confronted with the urgent problem of how to repair and design,restore the ecosystem of the watershed,improve the water environment of the watershed and enhance the water quality of the estuary of the Maolihu lake.In the paper,the author takes Zhoujiagang watershed of Maolihu Lake as the research object,and selects the rear section of the process control area of Zhoujiagang watershed as the designed area with the total design area of 45.05 hectares through the preliminary survey,analysis and research of the current conditions of the watershed.According to the survey on the estuary and surrounding area of process control area of Zhoujiagang watershed,Zhoujiagang watershed basin was home to 8,505 people in 2017.The pollution sources in the basin is mainly made up of rural domestic waste,agricultural non-point source pollution and pollution from livestock breeding.The total annual pollution are COD232.66t/year,TP5.78t/year,TN59.16t/year,and NH3-N45.55t/year.The domestic sewage discharge is 177961t/year.Based on the theories of restoration ecology,river ecology,landscape ecology,wetland ecology and so on,with reference of the excellent cases and research findings at home and abroad,the author concludes from the qualitative positioning of the overall goal of carrying out ecological restoration of Zhoujiagang watershed:improve the water quality and surrounding environment of the watershed,set rural plant landscape and aquatic plants as the theme to meet the needs of handling pollution,and build a ecological restoration project rolling wetland sewage resource utilization and ecological landscape construction into one.According to the present situation and regional characteristics,the overall design structure is set as one axis,two belts and three areas.One axis is Zhoujiagang watershed.Two belts include the first belt-the eastern basin of Zhoujiagang watershed,that is,the upstream of Tongxin bridge to the estuary and the second belt-the western basin of Zhoujiagang watershed,that is,the upstream of Tongle bridge to the estuary.Three areas are composed of tidal wetland restoration area,river branch wetland restoration area,and estuary wetland restoration area.At the same time,the author makes the corresponding designs for river ecological restoration,river base restoration,wetland ecological restoration,riparian buffer zone ecological restoration,plant restoration,hydraulic structures and revetment,road engineering and so on.In terms of the proper restoration design of the river,the author focuses on the natural design,the original river shape,add natural ecological river beach and river bend,restore the natural ecological structure of the river by planting different kinds of aquatic plants to improve the self-purification capacity of the river.Through the ecological restoration design of plants,the vegetation of wetland and bank slope,river channel and lakeside buffer zone is restored,so as to improve the vegetation coverage rate and water conservation capacity.At the same time,in view of the sewage treatment capacity of the original river,the wetland ecological restoration design is carried out,and the farmland runoff,aquaculture,domestic sewage and other sewage are purified and treated.The effluent quality control refers to the Class ⅡEnvironmental Quality Standard for Surface Water(GB 3838/2002).The vegetation buffer zone in the ecological restoration design of riparian buffer zone is an effective measure to prevent and control non-point source pollution.To be specific,the plants in the buffer zone can intercept and remove pollutants from runoff,contain soil and water loss,prevent erosion,and reduce sediment which pile into the river to form a natural landscape on the riverbank line and improve the rural living environment.In terms of the design of hydraulic structures and revetment,biotechnology,engineering technology and other measures are adopted to achieve the goal of effectively intercepting the nutrients lost from farmland and reducing water pollution materials,and stabilizing the shoreline through river regulation.Planting grass and trees and other biological measures are implemented to achieve the landscape effect of ecological beauty.In view of the road engineering design,the road system structure is optimized,and the road system is formed which combines the road and landscape according to the present terrain,physiognomy and the characteristics of Zhoujiagang watershed system.