Research On The Effect Of Atmospheric Nitrogen Deposition On The Drinking Water’s Quality Of Baixi Reservoir

Firstly, this paper qualitatively analyzes the relationship among basin rainfall and surfacerunoff concentration of Baixi reservoir, as well as the water quality of the reservoir, comes to theresult that atmospheric nitrogen deposition contributes to the total nitrogen of reservoir. Secondly,computes the nitrogen deposition critical load model of the basin, to get the deposition rate ofbasin ecosystem to atmospheric nitrogen. Thirdly, uses Black-box model, the linear relationshipbetween runoff and total amount of nitrogen deposition, to verify the reliability of the results; thenadopts Kichner-Dillon model to calculate environmental capacity of the reservoir and othernitrogen source, to get the pollution effect and contribution of atmospheric source towardsreservoir. This paper finally comes to the following conclusions:(1) The amount of atmospheric nitrogen deposition directly inflow into the reservoir is about5t/a, the output of atmospheric nitrogen deposition of other non-forest basins is49t/a, these twoadd up to54t/a. The critical load value of nitrogen deposition of Baixi reservoir basin is0.84g m~2a~1, and the critical load value of basin nitrogen is179t/a. The amount of overallnitrogen pollution source from the reservoir upstream is about350.16t/a, which is accord to theresult comes from the Black-box model that the overall nitrogen of upstream is about366.5t/a. Bycalculating the maximum nitrogen loading of water with Kichner-Dillon model, comes to that thestandard environmental capacity of water quality of typeⅠis63.4t/a, typeⅡ’s is158.5t/a.(2) The atmospheric nitrogen deposition accounts for the largest proportion of all kinds ofnitrogen pollution sources that inflow into Baixi reservoir. The proportion of absolute valuecontribution of each pollution source to reservoir nitrogen pollution in order from large to small is:atmospheric nitrogen deposition, human and animal’s life source, pollutants that inflow into therainwater collection area of Tiantai, pollutants carried by the forest surface runoff surroundingreservoir area, chemical fertilizer pollution of agricultural pollution sources, pollution from reservoir service and staff pollution of hydropower station along the reservoir, and tourismpollution.(3) According to the comparison between nitrogen concentration of rainfall in each month of2007and the standard nitrogen concentration (0.3mg/L) of eutrophication pollution, themonthly nitrogen concentration of rainfall exceeded the standard, which led to obvious pollutionto Baixi reservoir. While the average nitrogen concentration in2008was0.91mg/Lwhich hadalready exceed0.5mg/L, the standard water quality of type Ⅱ. Thus it had reached thewarning point of eutrophication pollution of the reservoir.