不同管理措施对密云水库流域水量水质变化的影响

在密云水库上游控制流域建立SWAT(Soil and Water Assessment Tool)水文模型,根据实测水量-水质数据对模型的参数进行优化。识别流域土壤侵蚀和污染物关键区域,并对不同管理措施对流域水量-水质的影响进行定量研究。研究结果表明:密云水库流域土壤侵蚀强度较大的集中在流域中下游临近河道的区域;潮河流域非点源污染状况较为严重,潮河和白河总氮流失超高风险区分别占总面积的62.62%和43.09%,白河流域总磷均为低流失风险区,潮河流域总磷高流失风险区占17.81%;等高耕作和梯田种植对于产沙量和污染物都有较好的去除效果,其中等高耕作对于产沙量和总氮、总磷负荷的削减率,潮河分别为25.16%、10.79%和32.89%,白河为47.60%、34.92%和53.49%;通过对比退耕还林和退耕还草措施得知,退耕还林的效果更优。研究结果可为密云水库流域水土保持和水环境治理提供决策依据。

Effects of different management measures on water quantity and quality of the Miyun Reservoir catchment

A SWAT hydrological model was constructed on the Miyun Reservoir catchment, and the parameters of the model were adjusted according to the actual water quantity and quality data. Based on SWAT simulation results, the critical areas of soil erosion and pollution were identified, and the effects of different management measures on water quantity and quality were analyzed quantitatively. The results are as follows. The areas of intense soil erosion are concentrated near the river in the middle and lower reaches of the Miyun Reservoir catchment. The non-point source pollution in the Chao River watershed is more serious. The areas with ultra-high risk of TN loss in Chao River and Bai River watersheds respectively account for 62.62% and 43.09% of the total areas. Bai River watershed has low risk of TP loss, while in Chao River watershed, the areas with high risk of TP loss account for 17.81%; Contour farming and terraced planting are both effective in reducing the amount of runoff, sediments, and pollutant load. Contour farming has reduced 25.16% of sediments, 10.79% of TN, and 32.89% of TP in Chao River watershed, and 47.60% of sediments, 34.92% of TN, and 53.49% of TP in Bai River watershed. Returning farmland to forests is more effective in pollutant reduction than returning farmland to grasslands. The research results can provide basis for decision-making in soil and water conservation and water environment rehabilitation in the Miyun Reservoir catchment.