Abstract
The implementation of the Water-Sediment Regulation Scheme (WSRS) since 2002 has changed the water and sediment entering the Yellow River Estuary, which may lead to adjustment of the estuarine channel. Based on the elevation data of 41 transects from 2002 to 2017 in the estuarine channel downstream from Lijin, we established a digital elevation model (DEM) based on curved orthogonal grids to investigate the spatiotemporal characteristics of channel erosion and deposition, and further analyzed its controlling factors combining the morphological changes of river mouth and water-sediment data. The results show that the Yellow River estuarine channel has undergone significant erosion with a total sediment volume of 62.4×106 m3 since 2002. The channel evolution process can be divided into three stages according to the rates of erosion or deposition, namely: rapid erosion (2002-2005), slow erosion (2006-2014), and slow deposition (2015-2017). Approximately 80% of the total eroded sediment was depleted in the first stage. The erosion flux has shown a significant decreasing trend after 2006, and the overall characteristic of the channel transferred from erosion into deposition afterwards. On a seasonal scale, the estuarine channel was eroded in the flood seasons and deposited in the non-flood seasons; from the spatial perspective, the erosion intensity decreased in the downstream direction. The operation of the WSRS changed the distribution of water and sediment entering into the sea during a year, most of which was delivered in a short time (no more than 20 days), thus caused the continuous erosion of channel as well as the morphological adjustments of the estuarine channel. As a result of the intensive erosion in the first stage, the estuarine channel riverbed has lowered so much, and accompanied by the impact of the extension of river mouth, the erosion efficiency decreased continuously. Besides, the channel reach near the mouth has undergone significant siltation after the first stage causing the decline of riverbed longitudinal slope, which increased the instability of the estuarine channel.
| Translated title of the contribution | Spatiotemporal evolution of Yellow River estuarine channel and its influencing factors since the water-sediment regulation scheme |
|---|---|
| Original language | Chinese (Traditional) |
| Pages (from-to) | 139-152 |
| Number of pages | 14 |
| Journal | Dili Xuebao/Acta Geographica Sinica |
| Volume | 76 |
| Issue number | 1 |
| DOIs | |
| State | Published - 25 Jan 2021 |