156 / 2024-02-23 08:05:49

Long-term dynamics and limits of the Yellow River water resources: Insights from sedimentary records and water balance modeling

Yellow River,sedimentary architectures,climate change,water resources

The Yellow River is the second longest river in China and once the largest sediment delivery river in the world. The upper reaches contribute ~60% of the total runoff, however, the Hetao Basin, which locates in the lowest section of the upper reaches, is the driest area in the Yellow River catchment. From the analysis of sedimentary architectures spanning the past 500 thousand years in the Hetao Basin, we reveal that during the dry and cold period, the upper Yellow River turned to be an inland river, which could not flow out of the Hetao Basin, as a result, tail-end lakes were formed. The area of the tail-end lakes of the upper Yellow River in the Hetao Basin fluctuated from 5, 300 km² to 34, 000 km², primarily influenced by the climate conditions. Using the water balance model, we reconstructed the upper and lower limits of hundred-year averaged annual runoff for the upstream Yellow River during the past 500 thousand years, the upper limit is ~280×10⁸ m³ around 128 thousand years ago, closely resembling the present gauged data and the lower limit is only ~76×10⁸ m³ about 18 thousand year ago, less than 30% of the present value. This study provides valuable insights into the long-term water resource dynamics of the Yellow River over a million-year time scale, offering significant benefits to theoretical research and long-term river planning.