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| Spatial distribution of water quality and its impacting factor in the wet season of Poyang Lake using the hydro-geomorphological partitions |
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Abstract Based on the in situ measurements from the field survey in July, 2011, the objective of this paper was to investigate the spatial distribution of the total suspended sediment (TSS), total nitrogen (TN), total phosphorus (TP), and chlorophyll a (Chl a), where their impacting factors were also studied by dividing the lake into 8 hydro- geomorphological partitions considering the hydrodynamic conditions. Results show that the TSS concentration was 33.65mg/L, which was three times higher than that of the average conditions before 2003. The N, P concentrations were 1.61mg/L and 0.075mg/L respectively, which appears much higher than the requirements of eutrophication. The average Chl a concentration was 5.99 μg/L, which was smaller than the threshold of being a eutrophic lake. Correlation analysis showed that TP and TSS were significantly correlated with each other in high sediment concentration regions, while no significant correlation was observed between the Chl a and other water quality parameters. In different hydro-geomorphological sections, due to pollution inputs from the watershed and sand mining activities within the lake, the TSS concentration of the northern high velocity water regions was three times higher than the river estuary area. TN and TP concentrations of the Ganjiang and Raohe river estuary area was larger than the northern high velocity water regions, where Xiuhe River estuary area andsome central lake area showed minimum TN and TP concentration. The hydrodynamics also played an important role in regulating the spatial distribution of TSS, TN, TP and Chl a in the lakes, Chl a concentration of the river estuary area was larger than the northern high velocity regions, while the Rao-Xin-Tong Jin River estuary area even reached 12.53μg/L, exceeding the low bound value of being a eutrophic lake.
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Received: 25 December 2013
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