Quantifying drivers of the sediment load reduction in the Yellow River Basin

Abstract

Human activities have significantly changed the transport and fluxes of terrestrial sediment of global rivers, trapping over 100 billion metric tons of sediment in reservoirs worldwide, reducing the sediment delivery to coastal areas, and affecting the environmental quality and economic vitality of coastal regions [1–3]. The impacts of reducing sediment loads of the global rivers include increasing coastal recession rate, threatening the safety of the coastal residents, changing the benthic environment of coastal estuaries, and productivity of coastal fisheries [1–3]. To tackle such impacts, it is essential to identify, understand, and quantify the drivers and their interactions that produce such sediment reduction. TheYellowRiverwas once theworld’s largest carrier of fluvial sediment load, withnearly 90%of it originated and transported from theLoess Plateau in themiddle reach (Fig. 1a) [2,3]. However, the sediment load has dramatically reduced, from∼1.6 billion tons/year in the 1970s to∼0.3 billion tons/year at present, a reduction of over 81% [2,3]. Such reduction not only resulted in significant improvement in ecosystem services such as ecosystem net primary productivity, soil carbon storage, and net ecosystem productivity over the Loess Plateau [2–5], but also led to decreasing water yield of both the lower reach and the delta of the Yellow River particularly in dry years [2–5]. Many studies have investigated the effects of coupled climate change and anthropogenic activities on sediment P1-P3 P1-P2 P2-P3 Periods