Recent anthropogenic curtailing of Yellow River runoff and sediment load is unprecedented over the past 500 y

Abstract

The Yellow River (YR) is the fifth-longest and the most sediment-laden river in the world. Frequent historical YR flooding events, however, have resulted in tremendous loss of life and property, whereas in recent decades YR runoff and sediment load have fallen sharply. To put these recent changes in a longer-term context, we reconstructed natural runoff for the middle reach of the YR back to 1492 CE using a network of 31 moisture-sensitive tree-ring width chronologies. Prior to anthropogenic interference that started in the 1960s, the lowest natural runoff over the past 500 y occurred during 1926 to 1932 CE, a drought period that can serve as a benchmark for future planning of YR water allocation. Since the late 1980s, the low observed YR runoff has exceeded the natural range of runoff variability, a consequence of the combination of decreasing precipitation and increasing water consumption by direct and indirect human activities, particularly agricultural irrigation. This reduced runoff has resulted in an estimated 58% reduction of the sediment load in the upper reach of the YR and 29% reduction in the middle reach.

Hydrological Extremes in the Upper Yangtze River Over the Past 700 yr Inferred From a Tree Ring δ18O Record

“…• Reconstruction of hydrological extremes in the upper Yangtze River over the past 700 yr using tree ring oxygen isotope • Extreme hydrological droughts have increased significantly under the background of ongoing global warming • Recent increase in extreme hydrological droughts is related to the weakening of India's summer monsoon due to increasing greenhouse gas emissions data and other proxies (Bekker et al, 2014;Gallant & Gergis, 2011;Y. Liu et al, 2020;Meko et al, 2012;Rao et al, 2020;Woodhouse et al, 2006).…”

Spatiotemporal Variations of Sediment Discharge and In‐Reach Sediment Budget in the Yellow River From the Headwater to the Delta

“…Forth, the diversion or consumption of streamflow may have also caused the differences in sediment transport trend. For instance, the trend difference of sediment transports between Tangnaihai and Hekouzhen stations after 1990 was greater than that before 1990 (Figure 6a), probably due to the significant sediment diversion in the lower part of the upper reach as a result of sharp increase of agricultural water consumption (Liu et al., 2020).…”

“…Besides the land use/cover changes induced by human disturbances, the direct anthropogenic activities, such as artificial water diversion and sand mining, also reduced the sediment load. This is particularly true in the lower part of the upper reach and the lower YR reach (Liu et al., 2020).…”

“…The homogeneity and reliability of the annual streamflow and sediment load data were checked and firmly controlled by the YRCC before the data were released. Thereby, this data set is reliable, and it is the official hydrological data widely used in previous studies (Liu et al., 2020; Song et al., 2020; Wang, Fu, Piao, et al., 2016; Yang et al., 2020).…”

Influences of the 1855 AD Huanghe (Yellow River) Relocation on Sedimentary Organic Carbon Burial in the Southern Yellow Sea

“…Combined with previous results, we propose a schematic diagram for the connection between this relocation event and OC burial in the southern YS and the ECS (Figure 9). In the ∼100 years before and after 1855 AD, the Huanghe runoff and its sediment load was relatively stable (Liu et al, 2020;Wu et al, 2020). When Huanghe emptied into the southern YS during the period 1128-1855 AD, Huanghe sediments were directly transported to the Jiangsu coast, and consequently more fine particles (Figure 4E, median grain size from a core 35009 which lies close to core HH12) were transported to the CSYSM.…”