Numerical Study Of Pollutants Fluxes Based On A Riverestuary Integrated 3D Model In The Pearl River Estuary

Since reform and opening up, the economy of Pearl River Delta grows rapidly, the urban domestic and industrial sewage discharge without effective treatment increases largely, the water environment in the estuary region become more worsen. So it is urgent to do some researches on the Pearl River Basin’s pollutant emissions. It seems especially important to calculate the pollutant emissions which flows into the Pearl River estuary accurately, and it is of great significance to the water resource management and implementation control of target pollutant emission.Base on the purpose, a 3-D coupled physical-biological model, which integrates the RNPRD, the PRE and its adjacent coastal sea has been developed to simulate the fluxes of four kinds of pollutants(CBOD,NO23,NH3,TP) into the Pearl river estuary, then compare the result with the flux calculated by traditional method,model method and the observational flux.. The main conclusions of this paper are summarized as follows:(1) According to the statistical result by predecessors, we recount and generalize the location of drains and the discharge of pollutant into the model in the study area, and using a dye model to calibrate them.(2)The result of the coupled model indicated that t the pollutant fluxes in the period of June 1999(wet season) are far greater than February 2001’s(dry season).The fluxes of pollutants(CBOD, NO23, NH3, TP) discharged into the Pearl river estuary in the wet season are about 5 times,6 times,3 times and 2 times of those in the dry season, respectively.(3)The ratios of pollutants fluxes flow into the estuary through eight openings are different at different season. In the wet season, over 80% of the fluxes of CBOD and over 78% of NO23 are entering the estuary by Humen, Jiaomen, Hengmen and Modaomen. The NH3 mainly through Humen flows into the estuary, over 65% of the TP via Humen, Jiaomen and Modaomen into the estuary. In the dry season, more than 72% CBOD discharges into the estuary by Humen, Hengmen and Modaomen, the NO23, NH3 and TP are about 58%, 55% and 57% of the total fluxes through the Humen and Modaomen flow into the estuary respectively.(4)Comparing the fluxes that calculated by three different methods with the observed fluxes, it can be drawn that in the wet season, using the model method calculated the pollutants fluxes has smallest error, but in the dry season, all three methods have no advantages.