Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States of America; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States of America.
Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States of America; Korea Ocean Satellite Center, Institute of Ocean Science and Technology, Busan, South Korea.
Sci Total Environ. 2020 Jul 15;726:138343. doi: 10.1016/j.scitotenv.2020.138343. Epub 2020 Apr 1.
River impoundments strongly modify the global water cycle and terrestrial water storage (TWS) variability. Given the susceptibility of global water cycle to climate change and anthropogenic influence, the synthesis of science with sustainable reservoir operation strategy is required as part of an integrated approach to water management. Here, we take advantage of new approaches combining state-of-the-art computational models and a novel satellite-based reservoir operation scheme to spatially and temporally decompose Lake Victoria's TWS, which has been dam-controlled since 1954. A ground-based lake bathymetry is merged with a global satellite-based topography to accurately represent absolute water storage, and radar altimetry data is integrated in the hydrodynamic model as a proxy of reservoir operation practices. Compared against an idealized naturalized system (i.e., no anthropogenic impacts) over 2003-2019, reservoir operation shows a significant impact on water elevation, extent, storage and outflow, controlling lake dynamics and TWS. For example, compared to Gravity Recovery and Climate Experiment (GRACE) data, reservoir operation improved correlation and root mean square error of basin-wide TWS simulations by 80% and 54%, respectively. Results also show that lake water storage is 20% higher under dam control and basin-wide surface water storage contributes 64% of TWS variability. As opposed to existing reservoir operation schemes for large-scale models, the proposed model simulates spatially distributed surface water processes and does not require human water demand estimates. Our proposed approaches and findings contribute to the understanding of Lake Victoria's water dynamics and can be further applied to quantify anthropogenic impacts on the global water cycle.
河坝强烈改变了全球水循环和陆地水储量（TWS）的变化。鉴于全球水循环对气候变化和人为影响的敏感性，需要将科学与可持续水库运行策略相结合，作为综合水资源管理方法的一部分。在这里，我们利用结合最先进的计算模型和新的卫星水库运行方案的新方法，对自 1954 年以来就受到大坝控制的维多利亚湖的 TWS 进行时空分解。地面湖泊测深图与全球卫星地形图相结合，以准确表示绝对水储量，并将雷达测高数据整合到水动力模型中，作为水库运行实践的代理。与 2003 年至 2019 年期间的理想化自然系统（即没有人为影响）相比，水库运行对水位、面积、储水量和流出量有显著影响，控制着湖泊动态和 TWS。例如，与重力恢复和气候实验（GRACE）数据相比，水库运行分别将流域范围内 TWS 模拟的相关性和均方根误差提高了 80%和 54%。结果还表明，在大坝控制下，湖泊储水量增加了 20%，流域范围内地表水储量对 TWS 变化的贡献为 64%。与大型模型现有的水库运行方案不同，所提出的模型模拟了空间分布的地表水过程，并且不需要人类水需求估计。我们提出的方法和研究结果有助于了解维多利亚湖的水动力，并可进一步应用于量化人为因素对全球水循环的影响。
