A Study On The Influencing Factors Of Apparent Pollution For Landscape Water Based On Multivariate Statistical Analysis

At present the urban rivers in our country, which are mostly static or slow-flow, havesmall water environmental capacity, poor self-purifying ability and vulnerable to bepolluted by the outside world, so the apparent pollution are pretty serious in the riverswhich appear to be under a state of high turbidity, low transparency, even be malodorousblack or having a water bloom. This paper took the river in Suzhou University of Scienceand Technology as an example to study the evolution law and the influencing factors of theapparent pollution in scenic rivers. The results could provide the theory basis for exlainingthe apparent pollution and provide the role of guiding predicting and preventing theapparent pollution.Four typical landscape river sections which has different exogenous characteristics,sediment characteristics, runoff characteristics and hydrodynamic conditions were chosento be the research objects and monitored from April2010to December2011, themonitoring indexes included sensuous quality, water quality indexes (COD_Cr, NH₃-N, TP,turbidity, smell and taste, pH, water temperature, DO, Chla concentration) andMeteorological factors （rainfall, temperature and light）. The main results of this researchpaper are:（1）During monitoring period, the whole sensuous quality of2011was apparentlyworse than2010. Among the four selected typical sections, the apparent pollution of theone which has been discharged into a large amount of waste water and endogenesis bottomsediment was the worst one and fluctuated very frequently; the apparent pollution of theone whose catchment zone were mostly constitute of concrete pavement and roof is seriouswas the next one; the apparent pollution of the ones which has no or less discharged wastewater and whose main catchment zone were grassland were relatively light; the apparentpollution of the one which has good hydraulic conditions was more stable. The apparentpollution of all sections were lightest and most stable in winter, the following seasosn werespring and autumn, the apparent pollution of summer was the worst and most unstable.（2） The results could be obtained with utilizing both single factor analysis andprincipal component analysis and stepwise regression analysis: the apparent pollution ofthe section whose main catchment zone was concrete pavement and roof was more likelyto be worse because of rainfall runoff; The temperature and light had more impact on theapparent pollution of the section which was more likely to have a water bloom.（3） The sensory quality of the sections which have different characteristics is more likely to be affected by different factors. When without good hydraulic conditions, theapparent pollution of the one which has been discharged into a large amount of waste waterand endogenesis bottom sediment was pretty serious; Water quality exchange was the mostimportant factor which could affect the section with large amount of water qualityexchange; The sections which have good hydraulic conditions had better affordability thanthe sections which have poor hydraulic conditions.（4） The factors which would make water malodorous black are endogenous sludge,input waste water and hydraulic conditions. The water bodies which have seriousendogenesis bottom sediment and large amount of input waste water are most likely to bethe source of the phenomenon of malodorous blacky; The water bodies whose depth areshallow are most likely to be influenced by hydraulic disturbance; Input waste water andwater quality exchange would be the reason of causing water bodies which have lessendogenous sludge malodorous blacky. All researched sections were possible to have awater blom under the weather which has high or jumping temperature, strong light and norainfall, the water bodies which were slow-flow and lighter polluted were more likely tohave water blooms than the water bodies which had frequently water quality exchangesand heavy organic pollution.