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论文类型：期刊论文

发表时间：2021-03-05

发表刊物：JOURNAL OF HYDROLOGY

卷号：590

ISSN号：0022-1694

关键字：Lancang-Mekong River; Phosphorus; Influence of dam construction; Nutrient retention; SWAT model

摘要：Nutrients are critical to the development of plant and animal life in the river ecological system. In recent years, more attentions have arisen on the impact of building hydropower dams to transborder nutrient flux in the Lancang-Mekong River Basin (LMRB). In this paper, phosphorus was taken as an example, which is considered as one of the most significant factors to limit biological activities in the river. The Soil and Water Assessment Tool (SWAT) was used to access the multisource loading pattern of Total Phosphorus (TP) under no-dam scenario, and various types of dam construction scenarios analyses were performed to investigate potential changes in the transborder TP flux from Lancang River Basin (LRB, Chinese part of LMRB) to lower LMRB (other parts of LMRB). The results showed that the Total Phosphorus load in the LRB is about 27,079 tons/year, of which 85% TP is collected from July to October. The annual TP export at the outlet of the LRB is 14,112 tons/year under nodam scenario, which accounts for about 4.2% of the total TP loads in the lower LMRB. With seven to twenty-one dams included in experiments, TP flux at the outlet of the LRB decreased 50-59%, while the delivered ratio for the lower LMRB decreased 2.1-2.5%. As a summary, building dams has a significant impact on the TP transport pattern in the Chinese part of LMRB, but very limited effect in lower LMRB according to the modeling results, especially for the Mekong delta. Moreover, the existing dams (seven dams) seem to intercept much more phosphorus than those dams that are under construction.