Simulation And Key Technology Research On Water Quality Of Sponge City

The rapid development of urbanization not only leads to climate change,but also makes our country face the problem of water resources shortage,rain flood events and water resources pollution.In recent years,the rain flood events have occured frequently,most area of the country fell into the embarrassing situation of the rain disaster,which not only caused the loss of national economy,but also make life less secure.In order to achieve better effect of flood and drainage control,combining the digital model,sponge city construction and city municipal pipeline engineering scientifically and reasonably,is the focus of future water research direction.This paper takes the test area in the city of Yixing as the research object,using three cavernous of permeable pavement,bioretention pool,rain garden sponge in city construction for rain and flood control measures,and based on the "infrastructure construction of low impact development scheme in Yixing" and the regulatory date,to simulate rainfall reappearing period of 1,3,5,10,15,50,100 year's rainfall intensity,using SWMM model to simulate the effect of rainfall flood control in the study area,simulated urbanization,permeable pavement,bioretention pond,rain gardens and other three kinds of combination of measures to study the water quality changes in the area.The analysis results of hydrological simulation mainly include surface mean runoff,average infiltration rate,peak flow and average runoff coefficient,main aspects of network nodes is node overflow and the number of overflow of nodes,in the aspect of water quality simulation,common pollutants like SS,COD,TN,TP in surface runoff of rainwater is control effects.And an example is given to verify the reliability of the model of hydrological and water quality simulation,using key technology to study flood control effect of different sponge rain and the calibration of model parameters.The results show that the permeability of the pavement,bioretention pool,rain gardens and three kinds of sponge combination measures could effectively reduce the average runoff,peak flow,average runoff coefficient,node overflow and overflow number and increase infiltration,and have good control effect to pollutants SS,COD,TN,the total amount of TP,its overall control effect is sorted as permeability pavement greater than three combination measures greater than rain garden approximate bioretention measures.Taking the actual rainfall data on July 4 and July 13,2016,verified that actual monitoring of water quality data and the analog data flow,SS,COD,TN monitoring data have a highdegree of authenticity in July 4,the true degree were 95.1%,85%,90.1%,86.5%,but the TP simulation deviation is 9.52%.By adjusting the model parameters and simulated again,the true degree of TP reached 81%;And using the real data on July 13 to fixed rate again,the results are as follows: the simulation of the flow,SS,COD,TN,TP data and monitoring data have a high degree of authenticity,the authenticity of the data are 88.89%,94.56%,96.24%,86.74%,80%,the actual reliability is higher.