基于SWAT模型的尼山水库面源污染最佳管理措施研究

为了更好地防控尼山水库的面源污染，采用已构建并通过率定的SWAT模型模拟最佳管理措施在尼山水库流域的减排效果，并分析其削减氮、磷负荷的时空变化特征。结果表明：化肥使用量减少50%、生态沟、植被缓冲带及退耕还林措施对氮、磷具有很好的削减效果，各措施分别对氮、磷的削减量为48.22%和52.41%、36.86%和52.73%、38.31%和51.00%、45.17%和38.53%；各措施对年内丰水期（6-9月）的总氮和总磷的入库削减效果最为明显，对总氮和总磷削减的空间分布影响较大。根据尼山水库流域的实际情况，对耕地多、降雨量大、坡度大的氮、磷流失高风险区应采取削减化肥使用量并布设生态沟、植被缓冲带等工程措施；在氮、磷输出负荷占比较小的区域应实行削减化肥使用量和等高种植等投入成本相对较低的管理措施，并积极开展退耕还林工作。

Best management practices for non-point source pollution in Nishan Reservoir based on SWAT model

To prevent and control the non-point source pollution in the Nishan Reservoir Basin, an established and calibrated SWAT model was utilized to simulate the results of best management practices (BMPs), and to analyze the temporal and spatial variation characteristics of total nitrogen (TN) and total phosphorus (TP) reduction. The results showed that the practices of 50% reduction of fertilizer use, ecological ditch, vegetation buffer zone and returning farmland to forest had a significant effect on the reduction of TN and TP, which reduced the TN and TP by 48.22% and 52.41%, 36.86% and 52.73%, 38.31% and 51.00%, 45.17% and 38.53%, respectively. The maximum reduction of TN and TP by BMPs was in wet period (June to September); however, different BMPs had great effects on the spatial distribution of TN and TP reduction. According to the current situation in the basin, the combined practices of 50% reduction of fertilizer use, ecological ditch and vegetation buffer zone should be applied to high-risk pollution areas with abundant farmlands, large rainfall and steep slopes; whereas the combined low cost practices of reduction of fertilizer use and contour cultivation should be arranged for low-risk pollution areas. Moreover, returning farmland to forest should be actively carried out.