Irrigation, damming, and streamflow fluctuations of the Yellow River

Abstract

The streamflow of the Yellow River is strongly affected by human activities of irrigation and dam regulation. Many attribution studies focused on the long-term trend of discharge, yet the contributions of these anthropogenic factors to streamflow fluctuations have not been well quantified. This study aims to quantify the roles of irrigation and artificial reservoirs in monthly streamflow fluctuations of the Yellow River from 1982 to 2014 by using the global land surface model ORCHIDEE with a new developed irrigation module, and a separate offline dam operation model. Validation with obsevations demonstrates 5 the ability of our model in simulating the main hydrological processes under human disturbances in the Yellow River basin.Irrigation is found to be the dominant factor leading to 63.7% reduction of the annual discharges. It might lead to discharge increase in the summer if irrigation is widely applied during a dry spring. After illustrating dam regulation as the primary driver affecting streamflow seasonality, we simulated the changes of water storages in several large artificial reservoirs by a new developed dam model, which does not require any prior knowledge from observations but only implements two simple 10 operation rules based on their inherent regulation capacities: reducing peak flows for flood control and securing base flows during the dry season. Inclusion of dams with this simplified model substantially improved the simulated discharge by at least 42%. Moreover, simulated water storage changes of the LongYangXia and LiuJiaXia dams coincide well with observations with a high correlation value of about 0.9. We also found that the artificial reservoirs can affect the inter-annual fluctuations of the streamflows, which however was not reproduced faithfully by our dam model due to lack of annual operation rules. From 15 1 https://doi.org/10.5194/hess-2020-7 Preprint. Discussion started: 16 April 2020 c Author(s) 2020. CC BY 4.0 License. the mismatches between simulations and observations, we inferred the potential impacts of multiple medium reservoirs and five large irrigation districts (e.g., the Hetao Plateau), which were ignored in most previous hydrological studies.More than 60% of rivers all of the world are disturbed by human activities (Grill et al., 2019) contributing to approximately 63% of surface water withdrawal (Hanasaki et al., 2018). River water is used for agriculture, industry, drinking water supply, and electricity generation (Hanasaki et al., 2018;Wada et al., 2014), these usages being influenced by direct anthropogenic drivers and by climate change (Haddeland et al., 2014; Piao et al., 2007Piao et al., , 2010 Yin et al., 2020;Zhou et al., 2019). In order 5 to meet the fast-growing water demand in populated areas and to control floods (Wada et al., 2014), reservoirs have been built up for regulating the temporal distribution of river water (Biemans et al., 2011; Hanasaki et al., 2006) leading to a massive perturbation of the variability of river discharges. In the mid-northern lat...

Characterization of SWOT Water Level Errors on Seine Reservoirs and La Bassée Gravel Pits: Impacts on Water Surface Energy Budget Modeling

“…As an example, it was demonstrated how the large increase of reservoirs in China during the last 20 years have impacted regional water budgets, especially evapotranspiration and its long-term trends [7]. In the same part of the world, a simple dam operation model was developed to explain the time variability of the discharges of the Yellow river and to separate the effects of climate change from human infrastructures [8].…”