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| Analysis of temporal and spatial characteristics of nitrogen pollution in Qingshan Lake basin based on SWAT model |
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Abstract A nitrogen load model has been constructed for Qingshan Lake Basin based on SWAT model. The model was calibrated and verified using the runoff measurements during 2005to 2011and water quality measurements during July 15to August 4, 2011. Main nitrogen sources include fertilizer use, domestic sewage, livestock, urban point source and wet deposition, among which fertilizer use is the biggest contributor to TN concentration at the outlet of the basin, amounting to 34.3% of the total. Temporal and spatial characteristics of the nitrogen load distribution have been analyzed using the model. The results show that seasonal characteristics of NO3--N loss are distinct, with 62.5% of the yearly total loss concentrated on the period of June to September; highest in the middle region and lowest in the northern west region (covered mostly by natural forest); overland flow is the main loss route for NO3--N; the highest loss of organic nitrogen is found in the middle region of the basin where farmland is the dominant land-use type. The results of the present study can contribute to the management and study of nitrogen pollution in basins.
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Received: 20 September 2014
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