流域吸附态磷时空分布模型的构建与应用  

Modeling spatial-temporal variation of particulate phosphorus at regional scales

作　　者：龙天渝[1,2] 刘佳[1,2] 王海娟[1] 刘敏[1] 

机构地区：[1]重庆大学三峡库区生态环境教育部重点实验室,重庆400045 [2]重庆大学低碳绿色建筑国际联合研究中心,重庆400045

出　　处：《农业工程学报》2015年第3期255-261,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金："十二五"国家科技支撑计划重点项目(2011BAD31B03);重庆市自然科学基金计划重点项目(CSTC;2011BA7021)

摘　　要：为了模拟吸附态磷负荷的时空分布,从被侵蚀土壤进入受纳水体的载体地表径流着手,综合考虑坡上和坡下的径流特性对被侵蚀土壤迁移的影响,引入时空分布的径流连通性指标,由此提出坡面泥沙输移比的计算方法。将改进的土壤流失方程作为流域土壤侵蚀量的计算方程,结合所提出的坡面泥沙输移比并考虑磷在土壤中的富集,构建流域吸附态磷负荷的时空分布模型。以三峡库区小江流域作为案例,对该流域2000-2010年的吸附态磷负荷的时空分布进行了模拟,模拟得到多年平均吸附态磷负荷为0.056 t/km2。模拟值与实测值吻合较好,其年平均吸附态负荷相对误差低于6%,表明所构建的模型以及所提出的坡面泥沙输移比的计算方法可行。该研究可为三峡库区的水环境保护和水污染防治提供参考。Phosphorus is the dominant nutrient causing the eutrophication in the Three Gorges Reservoir Area of China where there is abundant rainfall. The related studies report that about 85% of phosphorus exists in particulate phosphorus（PP）, and there are rapid and dramatic spatial and temporal variations in PP load particularly during the period of intensive rainfall. To estimate the spatial-temporal variation of PP load, it is important to simulate soil erosion and sediment-associated transport. For mountainous watershed, hillslope sediment delivery ratio（HSDR） coupled with empirical soil erosion model is helpful to improve the capability of simulating sediment delivery and PP pollutant load. Considering the runoff characteristics from upslope and downslope during the transportation course of eroded soil, and the time varying characteristics of runoff caused by climate conditions such as rainfall, a runoff connectivity index（RC） by modifying flux connectivity index（IC） was proposed to define the variable HSDR for the watersheds with inhomogeneous climatic conditions. And by combining the HSDR with the RUSLE and the enrichment ratio of phosphorus in soil, the spatial-temporal distribution model of PP load was developed. The model was applied in Xiaojiang watershed of the Three Gorges Reservoir Area, and the spatial-temporal variation of sediment yield was simulated and analyzed. The results showed that simulated values of sediment yield were consistent with the observed data, the range of relative error was within-10.77%-13.81%, and the Nash-Sutcliffe coefficient and the relative root mean square error were 0.93 and 0.106, respectively, while the Nash-Sutcliffe coefficient and the relative root mean square error were 0.81 and 0.124 respectively using the HSDR from IC. In addition, it could be seen that the model performed well with a determination coefficient of 0.98. For PP load, the range of annual value of relative error was within-7.77%-14.73% and the relative error was comparatively small, and henc

关 键 词：土壤 侵蚀 磷 坡面泥沙输移比 吸附态磷负荷 时空分布 

分 类 号：X501[环境科学与工程—环境工程]