AnnAGNPS模型在丹江库区黑沟河流域的模拟应用与检验

Applying and Testing AnnAGNPS for Pollutant Loads of Heigou Watershed in Danjiang Reservoir

采用连续型-分布式参数模型AnnAGNPS,并结合GIS技术,对丹江库区黑沟河流域2003年农业面源污染负荷进行了定量模拟,并且用同步水质监测数据检验了该模型在丹江库区低山丘陵型流域的适用性。研究结果表明:(1)2003年黑沟河流域输沙量为16714.81t,粘粒(<0.002mm)占78.01%;氮素流失量达91.82t,其溶解态氮占76.96%;磷素流失量达4.49t,其颗粒态磷占87.28%。(2)面源污染物向水体迁移具有明显的季节特征,主要集中在降雨量比较多的4～10月份。(3)土地利用方式是影响面源污染物流失的重要因素,居民用地、坡耕地和荒地是该流域污染物流失的关键源区。(4)AnnAGNPS模型对泥沙侵蚀和氮磷营养盐流失的模拟精度由高到低为:氮输出>泥沙模拟>磷输出,对氮的模拟能力较强,对泥沙模拟精度一般,而对磷的模拟则表现出较大的不确定性。

In this paper, AnnAGNPS model, in which GIS being integrated, was used to quantitatively simulate pollutant loads of Heigou watershed in Danjiang reservoir during the whole periods of 2003. The feasibility to apply this model in Danjiang reservoir area, typical foothill, was further validated with storm evens. The results showed that： （1） The amounts of sediment, total nitrogen and phosphorus were 16714.81t, 91.82 t and 4.49t respectively, in which the clay particles （〈0.002mm）, dissolved nitrogen and particular phosphorus accounted for 78.01%, 76.96% and 87.28%, respectively. （2） The loads of pollutant showed obviously seasonal characteristics, with the high loading in the periods from April to October. （3） The simulated results also indicated that the loads of pollutant were influenced significantly by landuse types. In Heigou watershed, resident, slopeland and wasteland were the typical sources of the loss of agriculture NPS pollution. （4） The simulation accuracy of sediment and nutrient （nitrogen and phosphorus） was as follows： nitrogen exports 〉 sediment yield 〉 phosphorus exports. Nitrogen exports were simulated efficiently with AnnAGNPS model and moderate accuracy was achieved for prediction of sediment yield, but the prediction of phosphorus showed obvious uncertainties.