The Key Laboratory of River and Coastal Engineering, Viet Nam.
Faculty of Hydrology and Water Resources, Thuy loi University, Viet Nam; Hydrologic Research Laboratory, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, CA, United States of America.
Sci Total Environ. 2019 Jun 10;668:768-779. doi: 10.1016/j.scitotenv.2019.02.368. Epub 2019 Feb 25.
The differences among countries in terms of physical features, governmental policies, priorities in short- and long-term water resources management may lead to conflicts in managing and sharing of water resources over the transboundary regions. Due to no formal data sharing agreement between countries, there has been usually no data availability at transboundary regions. In this study, a methodology, in which a physically-based hydrology model was coupled with a regional climate model, is proposed to reconstruct and evaluate hydrologic conditions over transboundary regions. For the case study, Thao river watershed (TRW), within Vietnam and China, was selected. The Watershed Environmental Hydrology (WEHY) model was implemented based on topography, soil, and land use/cover information which was retrieved from global satellite data resources. The watershed model-WEHY was first validated over the TRW, and then was used to reconstruct historical hydrologic conditions during 1950-2007. The results of this study suggest no significant trend in the annual streamflow over the target watershed. In addition, there is a time shift in the wet season between the upstream sector in China and the downstream sector in Vietnam over the TRW. The annual flow contribution from the upstream sector in China to the outlet of TRW is estimated to be around 66%, and the remaining 34% contribution comes from the downstream sector in Vietnam territory. Last but not the least, the annual flow as a function of return period varies not only with the return period but also as a function of the time window, reflecting the effect of the changing regime on the streamflows at the TRW. The evolution of the flow frequency through time is an evidence of the ongoing non-stationarity in the hydrologic conditions over TRW.
由于各国在自然特征、政府政策、短期和长期水资源管理重点等方面存在差异，可能导致跨界地区水资源管理和共享方面的冲突。由于各国之间没有正式的数据共享协议，通常在跨界地区没有数据可用。在本研究中，提出了一种将基于物理的水文学模型与区域气候模型耦合的方法，以重建和评估跨界地区的水文状况。选择越南和中国境内的洮河流域（TRW）作为案例研究。该流域环境水文学（WEHY）模型是基于地形、土壤和土地利用/覆盖信息构建的，这些信息是从全球卫星数据资源中检索到的。首先在 TRW 上验证流域模型-WEHY，然后用于重建 1950-2007 年期间的历史水文条件。研究结果表明，目标流域的年径流量没有明显趋势。此外，TRW 上中上游的雨季与下游的雨季之间存在时间上的错位。中国上游流域对 TRW 出口的年流量贡献估计约为 66%，其余 34%的流量贡献来自越南境内的下游流域。最后但并非最不重要的是，年流量作为重现期的函数不仅随重现期而变化，而且还随时间窗口而变化，反映了变化的水文条件对 TRW 流量的影响。随着时间的推移，流量频率的演变是 TRW 水文条件非平稳性的证据。
