Assessing Hydrological and Sedimentation Effects from Bottom Topography Change in a Complex River–Lake System of Poyang Lake, China

Abstract

In recent years, a dramatic decline in Poyang Lake water levels and a shrinking water surface have raised concerns about water security and the wetland ecosystem. Changes in bottom topography due to sand mining activities in the lake was supposed to be one of the influencing factors of these changes. In response to this issue, the current study analyzed the change of lake bottom topography from observed digital elevation model (DEM) data, and quantitatively assessed the spatial and temporal responses of lake hydrology based on the framework of the neural network and the sediment effect was examined afterward. Results showed a total volume of 11.54 × 108 m3/year (about 0.96 × 108 m3/year or 1.58 × 108 t/year sediment) in net change of lake bottom topography in recent years, among which 97% was directly exported by commercial sand mining. During the study period, 2000–2011, intensive sand mining extended the central part of Poyang Lake and widened and deepened the outflow channel of the northern lake. This great change of lake bottom topography caused an average annual increase of 182.74 m3/s of lake outflow and a decline of 0.23 m–0.61 m in water levels across the lake. However, lake water levels are not consistent and show remarkable spatial and seasonal differences. The effects of changes in lake bottom topography on lake hydrological processes continue to grow as sand mining activities in the lake continue. More research on the environmental impacts is required for sustainable management of the lake ecosystem.

Closure to “Impacts of Streamflow and Topographic Changes on Water Level during the Dry Season of Poyang Lake, China” by Feng Huang, Xunzhou Chunyu, Yuankun Wang, Xiao Zhang, Bao Qian, Dayong Zhao, and Ziqiang Xia

“…Previous studies have corroborated the effectiveness and robustness of back-propagation neural networks for modeling the water level of Poyang Lake (Li et al 2015;Ye et al 2019). In the original paper, Figs.…”

Seasonal Amplitude of Water Storage Variations of the Yangtze–Huai Plain Lake Group: Implicaion for Floodwater Storage Capacity

“…Therefore, the sediment deposition in these two lakes is probably more obvious compared to other lakes. Ye et al (2019) indicated a total volume of 0.096 Gt/yr sediment in a net change of lake bottom topography during 2000-2011, which did not suffer radical changes for Poyang Lake. Previous studies have also shown that Poyang Lake bathymetry in most areas is relatively stable, and the storage estimation bias caused by deposition processes is significantly less than 1% except for the dry season (Li Y. et al, 2020;Yuan et al, 2021).…”

Anthropogenic Modifications and River Ecosystem Services: A Landscape Perspective

“…River-bed stability and bank erosion Loss of productive cultivation areas [92,128] Food production Sediment deposition Loss of deep pools [129,130] Species diversity Impact on food webs [131,132] Species diversity Changes in sediment composition Impact on benthic communities [133] Species diversity Bathymetric changes Changes in water levels [134,135] Water availability…”