Sediment and Nutrient Trapping by River Dams: A Critical Review Based on 15-Year Big Data

Purpose of Review Free-flowing rivers act as conduits for sediment and nutrient transport from the land to coastal oceans. In the past decades, many of global rivers have been dammed for water resource management. The associated ecological impacts have become a wide concern, and have been intensively studied. In this work, we aim to review the research progress of the topic on sediment and nutrient trapping by river dams using CiteSpace, summarize the findings of previous literatures, and propose perspectives for future studies. Recent Findings We found that (i) this topic has been continuously concerned and the publication number has been increasing annually. In 2006–2021, there are 1385 publications in total, including 1318 articles and 23 reviews; (ii) dams can interrupt river connectivity and trap sediment and nutrients in reservoirs, greatly deceasing sediment and nutrient loads to coastal oceans; (iii) sediment and nutrient trapping by dams has caused a series of ecological impacts, including reservoir capacity loss, river channel erosion, river delta land loss, reservoir eutrophication, and massive greenhouse gas emissions. Summary This review summarized the changes of riverine sediment and nutrient loads caused by dams, and their impacts on river ecosystems. The following aspects should be concerned in future studies: the impacts of biogeochemical cycling within reservoirs on the stoichiometry and bioavailability of nutrients in dam discharge, the net greenhouse gas emissions caused by dams, and the cumulative impacts of cascade dams. It adds our comprehensive understanding of sediment and nutrient trapping by river dams and will be beneficial to future studies in this field.