A Mini-Review of Sediment Distribution Pattern and Its Ecological Impacts in Reservoirs

Purpose of Review

Rivers serve as primary pathways for sediment transport from land to ocean, transporting large amounts of sediment annually to nearshore areas. However, in recent decades, many global rivers have been obstructed by dams for water resource management, forming unique distribution pattern and causing ecological impacts, which have been extensively studied. This review utilizes CiteSpace to investigate studies on reservoir sediment distribution and its ecological impacts, summarizing existing research progress and proposing suggestions for future studies.

Recent Findings

We found that (i) this topic has received sustained attention, with an increasing number of publications annually. Between 2005 and 2025, there is a total of 6093 publications. (ii) Longitudinally, in a cascade reservoir system, the first reservoir, or one that has long functioned as the first, usually shows the highest sediment accumulation, with grain size gradually decreasing downstream. Within an individual reservoir, both sediment volume and particle size generally decline from the reservoir tail to the dam. (iii) Vertically, sediment concentration is higher near the reservoir bottom. Coarser particles settle quickly and accumulate at the bottom, while finer particles remain suspended in the upper layers for extended periods. (iv) Sediment distribution influences biogeochemical cycling in river ecosystems, resulting in a series of ecological impacts such as changes in nutrient regime in the water, greenhouse gas emissions, and heavy metal toxicity.

Summary

This review summarizes the progress related to reservoir sediment distribution and their ecological impacts, suggesting future research should focus on the biochemical characteristics of sediment particles and three-dimensional simulation of sediment transport in reservoirs. These studies will contribute to a comprehensive understanding of sediment distribution, ecological impacts, and potential mitigation measures in dammed rivers.