Watershed sediment cannot offset sea level rise in most US tidal wetlands

• 成果类型: Article
• 署名作者: Ensign, Scott H.; Halls, Joanne N.; Peck, Erin K.
• 署名单位: University of North Carolina; University of North Carolina Wilmington; University of Massachusetts System; University of Massachusetts Amherst
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11028
• DOI: 10.1126/science.adj0513
• 发表日期: 2023-12-08
• 关键词: suspended sediment; fluvial sediment; riverine sediment; recent trends; human impact; coastal; flux; discharge; nutrient; drainage

摘要

Watershed sediment can increase elevation of tidal wetlands struggling against rising seas, but where and how much watershed sediment helps is unknown. By combining contiguous US datasets on sediment loads and tidal wetland areas for 4972 rivers and their estuaries, we calculated that river sediment accretion will be insufficient to match sea level rise in 72% of cases because most watersheds are too small (median 21 square kilometers) to generate adequate sediment. Nearly half the tidal wetlands would require 10 times more river sediment to match sea level, a magnitude not generally achievable by dam removal in some regions. The realization that watershed sediment has little effect on most tidal wetland elevations shifts research priorities toward biological processes and coastal sediment dynamics that most influence elevation change.