CAJ | 학술논문

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。
위료모의흡부태린부하적시공분포，종피침식토양진입수납수체적재체지표경류착수，종합고필파상화파하적경류특성대피침식토양천이적영향，인입시공분포적경류련통성지표，유차제출파면니사수이비적계산방법。장개진적토양류실방정작위류역토양침식량적계산방정，결합소제출적파면니사수이비병고필린재토양중적부집，구건류역흡부태린부하적시공분포모형。이삼협고구소강류역작위안례，대해류역2000－2010년적흡부태린부하적시공분포진행료모의，모의득도다년평균흡부태린부하위0.056 t/km2。모의치여실측치문합교호，기년평균흡부태부하상대오차저우6%，표명소구건적모형이급소제출적파면니사수이비적계산방법가행。해연구가위삼협고구적수배경보호화수오염방치제공삼고。
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 hence the simulation results were still satisfactory. From the distribution of PP load, it could be seen that the most serious regions of PP load caused by the accumulation of erosion sediment along rivers were Puli river, Dong river downstream, Nan river coast and Pengxi river, where the land use types were mainly dry land, paddy field and other fields. For the Taoxi river basin, upstream of the Dong river and Nan river downstream where were mainly grassland and forestland, the PP load was relatively low. According to the analysis of the proportion of different land use types, dry land was the largest, with 59.97%, the second was grassland with 19.75%, paddy field, forest land and water area were relatively small, with 8.12%, 6.31% and 5.62% respectively, and unutilized land and residential land accounted for 0.12% and 0.11% respectively. These were consistent with reported results. Thus, the calculation precision of the developed model in this paper has been greatly improved and the model is feasible. The model can be used as a major tool to assess sediment yield risks and PP load at mountainous watersheds.