| The water quality of artificial lake and creek in city seriously affect people’s daily lifeand aesthetic, but in some cities that point source has been basic controled, non-point sourcehas become a major pollution sources of the pollution of the lake and creek,so the non-pointsource pollution control has become the key of whether the urban water environment is goodor bad.This paper, take Xinhepu creek as an example to carry out a systematic studies, includethe contents of the following three parts:(1)Non-point source pollution load calculation method research。There are three maincategories quantitative accounting methods of non-point source pollution load of urban area atpresent.One is the machenical method based on the process of pollutants generation andemission;the second is the mean concentration method according to the synchoronousobservation of water quality and quantity;the last one is the statistical method based on waterquality and quantity monitoring to indirectly get annual rainfall runoff pollution load byestablishing relationship beteween inpact factors and pollution load or correlation beteweenvarious pollutants load.(2) Selected three typical drainage area,residential areas, roads and grass, as a monitoringobject,and monitored more than one rainfall runoff. Through data analysis of monitoringresults we found that there is an obvious first flush effect in the residential area and the road,the unobvious correlation of TSS and COD may be due to many factors affecting theunderlying surface and complex mechanism; the reason why TSS has an obvious correlationwith BOD,ammonium nitrogen and COD but not obviously with TN or TP in grass rainfallrunoff may be the effect of applying fertilizer.(3)Establishment of non-point source pollution load model of Xinhepu drainage area andparameter calibration.Based on the analysis of terrain elevation and drainage network,theXinhepu drainage area is generalized as a non-point source pollution load model containing91sub basins,609nodes and762section of pipeline,the drainage area are consist of threekinds of underlying surface types inclunding residential area,road and grass and eachunderlying surface can release all six kinds of pollutants that is TSS,COD,BOD,TN,TP andammonium nitrogen. The peak error is less than20%in parameter calibration of this model.(4)Pollution load simulation and calculaiton of study area.Do quantitative study ofnon-point source pollution load of Xinhepu drainage area by building a drainage areanon-point source pollution load model. The results show that the greater the intensity ofrainfall is,the greater the total quantity of pollutants into river and the frontier the concentration peak appear in the concentration process.Under the same intensity rainfallcondition,the order of the size of the emissions of pollutants are as follows: Peak appears inthe back of the rainfall process>Peak appears in the middle of the rainfall process> Peakappears in the front of the rainfall process. With the rain peak pushed back, the output ofpollutants presents the phenomenon of planation,but the amount of pollutants generated byrunoff erosion is basically the same. Pollution load of the green area was significantly lowerthan the commercial and residential,commercial and residential areas are the main elementsproducing non-point source pollution; Appropriatly increase the frequency of cleaning caneffectively reduce the non-point source pollutants generated by runoff, the higher Cleaningfrequency is, the more pollutants reduce.(5)Develop Guangzhou non-point source pollution load accounting system based onArcGIS。This system use SWMM to compute and ArcGIS to require,modify parameters andshowing the simulation results,that giving a richer and intuitive expression. |
PDF Full Text Request