Integration Of Ecological Restoration Technology About Rural Middle And Small Rivers In Plain Area

The rural rivers in the plain area,especially the middle and small rivers,are influenced by the human production and the life,resulting in natural ecology has been destroyed and a lot of negative effects,The main performance in the serious water pollution and water attenuation,even dry riverbed structure and stability decrease and shore river with ecological function degradation,river habitat diversity and biodiversity significantly,serious flood hazards etc.Rural river ecological environment is not optimistic,and the improvement of people’s living standards,residents of the river remediation requirements are increasingly high,the urgent need to strengthen the comprehensive improvement of rural river dynamics,so as to improve the living environment.This paper selects the typical town as the study area,using AHP-comprehensive evaluation index method was built based on the natural structure of health,ecosystem health and social service status as the criterion layer in the plain area of rural small river and ecological diagnosis system,on the rural small and medium-sized rivers in Suzhou were diagnosed according to the diagnostic results,puts forward the ecological revetment,ecological floating bed,ecological wetland,sediment dredging,ecological water,communication water ecological restoration technology,and through the indoor experiment,the degradation coefficient of physicochemical index,the pollutants from the water and plankton were studied on the three aspects of ecological restoration techniques,intended as the basis for the ecological restoration scheme,such as technology,communication and the river ecological water ecological restoration of joint programs,and to predict and evaluate the effect after repair.The paper main conclusions are as follows:(1)In the construction of diagnosis system about the small and medium river in plain area,the standard level of ecosystem health,the index layer in the river ecological water demand guarantee rate of the weight of the largest;the channel level,rare aquatic survival status,water resources development and water utilization,comfortable landscape the degree of morbidity level;comprehensive evaluation of health status of rural small river in Suzhou area index was between sub health-health,the natural structure of health,ecosystem health,social service condition evaluation index were ill health and sub-health-sub-health,sub-health-health are.(2)From the physical and chemical indicators of water quality,the representative river water COD and BOD5 respectively in 25~40mg/L and 4.0~9.0mg/L,and without governance > block revetment > ecological revetment management > the ecological floating bed > sediment dredging > ecological wetland;DO is between 2.0~6.0mg/L,and the ecological wetland ≈ the ecological floating bed > sediment dredging > ecological revetment ≈block revetment> without governance;NH3-N,TP,0.6~2.4mg/L,0.10~0.35mg/L and TU respectively in 5.0~56.0NTU,and without governance > block revetment > ecological revetment > ecological floating bed > wetland > sediment dredging.(3)The degradation coefficient of each representative river water KCOD: ecological wetland > ecological floating bed > an ecological revetment governance > without governance > block revetment > sediment dredging;KBOD5: ecological wetland> ecological floating the bed > an ecological revetment governance > without governance > block revetment > sediment dredging;KNH3-N:ecological wetland > ecological protection > ecological floating bed > block revetment > sediment dredging > without governance;KTP:ecological wetland > ecological floating bed > sediment dredging > ecological revetment > block revetment > without governance.(4)From the plankton biomass,number of plankton populations categories represent river water: ecological floating bed > stakes+ natural revetment > ecological revetment > block revetment > sediment dredging;plankton density: stakes+ natural revetment > ecological floating bed > ecological revetment > block revetment > dredging;Margalef diversity index: ecological floating bed > stakes+ natural revetment > ecological revetment > block revetment> sediment dredging.(5)Ecological water solution,the river section from the water make up distance,replenishment time,water flow direction,water flow,water inlet and the water inlet position number of water metabolism rate has certain influence.Among them,the Yao River Gate is too m3/s for the 5 water inlet,water scale(scheme 1-3)and the stone gate,Yao Bang too River Gate for the replenishment port,2 m3/s and 3 m3/s water scale(scheme 3-7),in 20 h water replenishment average metabolic rate were 46.3% and 51.3%,in water 80 h the average water metabolic rate were 96.9% and 97.7%;(6)Before and after the water communication section of water metabolism is different,the overall metabolic rate of river water system planning was higher than before planning,water planning and the backwaters of more before decapitation bang,high concentrations of pollutants more areas.Such as Yao Tai River Gate for the replenishment mouth,5 m3/s water scale,water system planning before and after water planning 20 h replenishment water average metabolic rate were 46.3% and 38.1%(7)The study area of river ecological water demand and the minimum flow rate between 1.41~4.05 m3/s and 0.40~0.54 m/s;in stone gate,Yao Bang too Ma Zhuang Gangzha river sluice and water inlet,water flow rate is 3 m3/s,the average value of river water flow and flow rate were 1.76m3/s,0.47 m/s,meet the ecological demand of the river,has a good effect on the hydrodynamic and ecological water requirement of river improvement.