Evidence and Causes of Spatiotemporal Changes in Runoff and Sediment Yield on the Chinese Loess Plateau

Abstract

Climate change and human activities are strongly influencing the eco‐hydrological processes of the Chinese Loess Plateau. It is challenging to investigate the spatiotemporal changes of water and sediment yields and identify their potential causes. In this study, we used the annual runoff index (WI) and specific sediment yield (SSY) derived from 58 hydrological stations to quantify the changes and attempted to explain their potential causes. The WI exhibited significant (P < 0.05) decrease ranging from −0.1 to −2.6 mm yr−1 during 1957–2012 in 44 sub‐catchments. Similarly, the SSY in 52 sub‐catchments reduced in a range between −2.86 and −636 Mg km−2 yr−1. The region of Toudaoguai–Longmen has extremely high SSY ranging from 8000 to 41 000 Mg km−2 yr−1 during 1957–1969. Budget analysis suggested that the area of Lanzhou–Toudaoguai contributed limited sediment but extracted large amount of water. The areas with negative SSY were increasing and mainly distributed along the mainstream of the Yellow River. The Loess plateau was becoming drier and warmer since the 1950s, whereas the intensive human activities including water withdrawal, soil and water conservation projects and the operation of dams and reservoirs are the dominant factors for the decline in WI and SSY on the Loess Plateau. Copyright © 2016 John Wiley & Sons, Ltd.

Spatio-temporal patterns of the effects of precipitation variability and land use/cover changes on long-term changes in sediment yield in the Loess Plateau, China

“…The historically severe soil erosion in the LP is due to sparse vegetation, intensive rainstorms, erodible loessial soil, steep topography, and a long agricultural history (Rustomji et al, 2008). To control such severe soil erosion, several SWCMs, including terrace and check-dam construction, afforestation and pasture reestablishment, have been implemented since the 1950s (Yao et al, 2011;Zhao et al, 2017). A large ecological restoration campaign, the Grainfor-Green (GFG) project converting farmland on slopes that exceed 25 • to forest and pasture lands, was launched in 1999 (Chen et al, 2015).…”

“…Consequently, the sediment yields within the LP have showed a predictable declining trend over the past 60 years (Zhao et al, 2017), resulting in approximately a 90 % decrease in sediment yield in the YR (Miao et al, 2010(Miao et al, , 2011Wang et al, 2016). Many other studies have detected the influences of LUCC and precipitation variability on sediment load changes within the LP.…”

“…Rustomji et al (2008) estimated that the contribution of catchment management practices to the decrease in annual sediment yield ranged between 64 and 89 % for 11 catchments in the LP during the 1950s to 2000. Zhao et al (2017) examined the spatio-temporal variation of sediment yield from 1957 to 2012 across the LP, and indicated that the adoption of large-scale SWCMs led to significant reduction of sediment yield between Toudaoguai and Tongguan stations, and large reservoir operation played a critical role in sediment yield reduction between Tongguan and Huayuankou stations. Zhang et al (2016) pointed out that the combined effects of climate aridity, engineering projects, and vegetation cover change-induced significant reductions of sediment yield between 1950 and 2008. found that engineering measures for soil and water conservation were the main factors for the sediment load decrease between the 1970s and 1990s, but large-scale vegetation restoration campaigns also played an important role in reducing soil erosion since the 1990s.…”

The synergistic effects of afforestation and the construction of check‐dams on sediment trapping: Four decades of evolution on the Loess Plateau, China

“…The construction of check‐dams has progressed rapidly since the 1970s as construction techniques have improved, and the government has implemented numerous projects (Zhao et al, ). Field surveys obtained by the Yellow River Conservancy Committee (YRCC) in 2009 indicated that more than 5,000 large and medium‐sized check‐dams have been constructed in this region, and a large proportion of these check‐dams are sited between Toudaoguai and Longmen stations (see Figure for the locations of these stations).…”

The impact of standard preparation practice on the runoff and soil erosion rates under laboratory conditions

“…Although the measurement of runoff and sediment using rainfall simulators can be performed in the laboratory (Gholami et al, 2014;Bochet, 2015;Rodrigo Comino et al, 2015b, 2016aSadeghi et al, 2015) and field conditions (Cerdà et al, 2009a;Lieskovský and Kenderessy, 2014;Biswas et al, 2015;Bochet, 2015;Pereira et al, 2015;Ochoa et al, 2016;Rodrigo Comino et al, 2016), field measurements are usually costly and time-consuming work. In addi- tion, different methods of measuring runoff and erosion may lead to non-identical results that are not necessarily related to specific effects on studied variables (Cerdà et al, 2009bSelkimäki et al, 2016;Zhao et al, 2016). Nowadays, the use of rainfall simulators in laboratory and field studies is considered more and more because of their ability to control the intensity and duration of rainfall, which leads to an increase in the accuracy of data (Sadeghi et al, 2015;Davudirad et al, 2016).…”