Pollutants Total Maximun Dalitly Load Estimation And Distribution Of Poyang Lake

Poyang Lake is the largest freshwater lake in our country, and its ecological security influences parts of provinces and municipalities in the middle and lower reaches of Yangtse River. Nowadays, Poyang Lake faces to some problems like water quality deterioration, habitat degradation and biological diversity decline etc. The study on Poyang Lake TMDL (Total Maximum Daily Loads) can help analysis existing pollution load of Poyang Lake, offer reasons for pollution into the lake gross control and point out direction for pollution control. Poyang Lake TMDL study contributes to its water resource and water environment protection, Poyang Lake area economic development faster, sustainable development protection coordination, especially to Poyang Lake watershed and the middle and lower reaches of Yangtse's sustainable.There are many factors needs to be considered in the study on the Poyang Lake TMDL. Here we need to do many investigations and calculations. There are as follows.Water balance of Poyang Lake, which is the basic information of the lake and needs to be learnt, contains water quality, water quantity and analysis pollution's distribution analysis. In Poyang Lake, NH₃-N pollution which mostly concentrated on the west of the lake was much worse, apparently due to the influence of main streams (into lake). TP pollution of the lake was extremely serious in low-flow season and TP concentration exceeds the standard in most parts of the lake, while Xin River brought out the most influence to TP gross. COD_Mn concentration were much steady, and fewer areas had a high value, no exceeding phenomenon. All kinds of pollution mainly concentrated in the inlet of stream-to-lake for the convergence streams' pollutions which enhanced the lake pollution, so the mixed area should be the key one that needed to do environmental capacity estimation.The easy polluted area's TMDL should be considered and estimated on the premise of satifying requirement of water quality of each function area. The COD TMDL of the main in-lake streams were all plus values, which means Poyang Lake's carring capacity was large enough to bear the currently pollution load. NH₃-N pollution was much obvious, especially in Gan River and Le'an River, whose NH₃-N TMDL was negative in months. The main reason of COD and NH₃-N TMDL fluctuate is the stream changing, if lake water renewal accelarates, TMDL increases. In low-flow season, TP pollution was extremly serious and most monitaring section datas show TP exceeding. Gan River, Xin River and Le'an River whose TP TMDL almost were negative were the worsest TP polluted River. When the TP concentrarion of the main rivers were exceeding, the river water would heavily impact on the lake, which can conduce to more exceeding phenomenon and then decreased TMDL. Otherwise, if the rivers' TP concentration were lower than the certain requirement, the lake's self-purification and dilution function worked effective, and then TMDL increased.A NH₃-N and TP reduction plan was proposed based on the exceeding situation, then, according to the surplus amount of TMDL, the author put forward the rational TMDL distribute plan, and pointed out the pollution treatment directions and targets. Among the basins, the largest NH₃-N reduction appeared in June of Le'an River and in Nov. of the middle and south tributary of Gan River. So the key point of Poyang Lake pollution control is NH₃-N and TP control, and the key treatment areas are Gan River and Le'an River, while TP pollution of Xin River should also be noted. The control of non-point source is much difficult than the point source control for it's reasonable that TMDL of non-point source assigned value is much larger than point souce in all streams.According to the worsely polluted area and its capacity situation, pollution control measures were raised. The TMDL's control can be done through the four pollution reduce projects and the water pollution control assessment. The four projects are like these: enhance water pollution control project, build up industrial development model project, improve the policy and rules project, and carry out total pollution amount control project. Pollution control assessment measures are as follows: enhance scientific research, perfect monitor system, implementation and carry out the TMDL plan, promote public participation, build up management files to assess TMDL implemetation result and so on.