Research On The Evaluation Index System Of Urban Inland River Water Health

Urban rivers provide various ecological services such as flood storage and landscape for the city.It promotes urban development in all aspects of natural,social,economic and environmental values.The impact of human activities on urban rivers has led to increasingly serious water pollution.The urban rivers have gradually become malodorous.The malodorous urban rivers have a direct impact on the production and life of the masses.This thesis summarizes the indicators involved in the index system of river health assessment at home and abroad,and combines the actual situation in jianye district.Thirteen indicators including physical,water environment,biological,and artificial intervention of river habitats were selected as indicators of urban river health.Adopting expert consultation method and analytic hierarchy process to construct urban river water health evaluation system.This evaluation system was applied to the evaluation of the water health of inland rivers in jianye district.In this study,35 rivers in jianye district and Nanhu Lake and Mochou Lake,were taken as research objects.We set up 41 sampling points to collect water quality monitoring data for each month of 2017-2018.We also conduct research and take photos.The main research contents and conclusions of this thesis are as follows:(1)Established an urban river water health evaluation system based on 13 indicators in four aspects.The expert consultation method and analytic hierarchy process are used to determine the index weight.(2)This thesis uses the index system to evaluate 35 rivers and two lakes in jianye district,and divides urban rivers into five levels of excellent,good,general,poor and worse.The study found that the water quality in the south of jianye district is obviously better than that in the central and northern regions.In the south of jianye district,many rivers have retained their natural conditions.The river bank type is mainly natural soil bank,the vegetation coverage around the river is high,and the ecological environment is good.However,the middle and northern rivers in jianye district are located in the built-up areas of the city,and the channelization of the rivers is serious.The river banks are mainly vertical reinforced concrete,and the river bank vegetation coverage is low.(4)In order to establish the goal of urban inland water governance,marginalrevenue(MR)and marginal cost(MC)curves are used to study the economy of urban inland river management.Under the current water environment treatment technology and economic level,the optimal cleanliness of water environment economy is level IV water body,and the corresponding river health condition is general.With the development of science and technology,the water treatment technology will be gradually improved.It is expected that the water body restoration target in jianye district will reach the level III in the future,and the corresponding river health condition shall be good.(5)In the future,the target of urban inland river water body restoration will reach the level III water body.It is far from enough to simply use the current mechanical means of artificial flushing,aeration and desilting.Instead,we should fundamentally open up the broken river and increase its connectivity.The goal of river regulation in the future should be to increase the ecological management,rebuild the aquatic ecosystem,restore the self-purification ability of the river,and finally restore the river to the natural channel.The ultimate goal of future urban river management should be to restore rivers to natural channels.