Research On Measurement And Evaluation Methods Of Stormwater Runoff Pollution Load

Storm runoff pollution can not be ignored in the surface water environment research.In the process of urbanization,in some areas where there is not enough monitoring methods,monitoring equipments and monitoring data,if we want to accurately assess the level of urban surface runoff pollution and control runoff pollution,the measurement and evaluation methods of rain runoff pollutants total amount is increasingly important for us.The research object of this topic is rain runoff,mainly studying rainwater runoff flow measuring method,device and the correlation between pollution indexes,so we can study the evaluation method of total amount of rain runoff pollution and provide the quantitative data for the control and management of receiving water quality.At the same time,the research results can provide scientific theoretical basis and technical support for the urban rainwater drainage system planning design and management.It is difficult to monitor the surface runoff flow with other measuring equipments.To solve this problem,a new flowmeter equipment for water inlet runoff quantity is brought forward,which is based on the rate of change of momentum to measure flow impact.Through force sensing device and weight transmitter,falling water flow impact pressure is converted to voltage signal.According to the change of voltage value in the process of calibration experiments,eventually it is converted to storm water inlet runoff quantity.The result shows that this kind of measuring method can get high flow precision and adapt to the change of storm water inlet runoff quantity,which is an effective approach of measuring storm water inlet runoff quantity.Then considering the rainwater drainage method and process,the flow calculation methods,equipment characteristics and their scope of several commonly used weir troughs have been analyzed and compared.And this paper analyzes the problems and the main points of rainwater open channel flow measurement and discusses the equipment selection of rainwater open channel flow measurement.Rainwater open channel flow is the basic data of migration and transformation rule of urban non-point source pollution load and the rainwater runoff pollutants.This paper mainly studies parshall flume,using the simplified model bashir's to study the measurement method rainwater open channel flow.Through hydraulic characteristics experiment rating the design parameters of the model.Under the condition of free flow fitting out the formula of depth of the water-flow and relations between the upstream water level and the head loss of model,at last,the paper validates the precision of the improved groove type by 1:2 length scale to reduce the model.This study shows that the precision of the established simple parshall flume model,whose R2 is more than 0.990 and Er value is within 5%,is good.And it used to measure the rain runoff flow is very effective.Second,in the "twelfth five-year" country "water pollution control and governance" major science and technology subject(water pollution and governance)(2010ZX07320—002)project,we monitor the part areas of the bright new district in Shen Zhen city demonstration project and get the storm runoff flow of different underlying surfaces and associated pollutants concentration.Then this paper analyzes the monitoring data of pollutant indexes and Pearson correlation coefficient of the rainfall characteristics and make sure the principal component factors of the pollutant load by Using the principal component analysis(pca).Finally,based on the BP Artificial Neural Network(ANN)this paper builds the evaluation model of rain runoff pollutants total amount.It makes use of the monitoring area 20 times rainfall from 2014 to 2015 as sample data.With principal component factors as input and pollutants(SS)as output,we set up three layers BP neural network model,calculate the corresponding year rain runoff pollution load by SPSS and MATLAB tool and verify the calculation results by Schueler method.Although the BP neural network application has become more widely,we has not yet used BP neural network model to evaluate pollutant total amount.So using this method to estimate the rainwater runoff pollution total amount is novel and far-reaching.In this paper,the research methods provide some new ideas for the rainwater runoff flow measurement and the evaluation of pollutant total amount in China,at the same time it promotes the sponge city construction and provides methods and technical support for strengthening the management of rainwater.