基于SWAT模型的植草河道对非点源污染控制效果的模拟研究

Effectiveness of Vegetated Waterway in Controlling Non-Point Source Pollution Based on SWAT Model

以三峡库区香溪河流域为研究区,基于SWAT模型,通过收集整理香溪河流域2011年DEM、土壤、土地利用数据和1970—2011年的气象数据,在模型得到满意的率定和验证的基础上,模拟分析了流域内农业非点源污染的空间分布特征,评价了植草河道措施对于农业非点源污染的削减效果。模拟结果表明,SWAT模型能够较好地模拟研究区非点源污染,研究区TN和TP污染负荷集中分布在南阳水系,以及古夫、高岚水系的下游区域。全流域TN和TP污染总负荷分别高达1388t和239t。实施植草河道措施之后,TN和TP污染负荷分别降到1120t和157t,共削减了16.7%的TN负荷和34%的TP负荷。因此,从控制效果来看,植草河道能够很好地控制三峡库区香溪河流域的农业非点源污染,尤其是对TP污染控制效果更加明显。

Non-point source（NPS）pollution is considered to be a major contributor to local water degradation in the Three Gorges Reservoir Area of China. Xiangxi River, which is a large watershed near the Three Gorges Reservoir, was selected to investigate the effectiveness of vegetated waterway in alleviating agricultural NPS pollution using SWAT（Soil and Water Assessment Tool）model. DEM, soil data, land use data in 2011 and the meteorological data from 1970 to 2011 were input to the SWAT model to simulate total N（TN）and total P（TP）pollu-tion loads before and after applying vegetated waterway management in 2011. The pollution loads were divided into five classes with Jenk optimal methods. The SWAT model generated satisfying results. Total N and TP pollution loads were 1388 t and 239 t, respectively, which were both concentrated in Nanyang River and the downstream of Gufu and Gaolan River. Applying vegetated waterway reduced TN and TP pollution loads to 1120 t and 157 t, respectively. The reduction rates of TN and TP were 16.7%and 34%, respectively. These results could help local managers design effective management practices to improve water quality in similar watersheds.