Soil reinforcement by a root system and its effects on sediment yield in response to concentrated flow in the loess plateau

Obtaining practical thresholds for erosive rainfall plays a crucial role in calculating rainfall erosivity and predicting water erosion. Nevertheless, the study of thresholds on subwatershed and watershed scales remains scarce. Given this, we presented the critical rainfall that generated the outflows of subwatersheds and watersheds as the threshold of sediment-generating rainfall. On the basis of the observation of twelve nested topographical units at the Peijiamaogou watershed in the Loess Plateau of China, we fitted regression relationships between rainfall indexes (rainfall amount, maximum 30-min intensity, maximum 60-min intensity, rainfall amount multiply maximum 30-min intensity, and rainfall amount multiply maximum 60-min intensity) and the proportion of cumulative sediment yield to the total sediment yield. We determined the thresholds of sediment-generating rainfall and explored the variabilities of thresholds across different spatial scales. Moreover, the covering area proportion (CAP) with rainfall indexes higher than the thresholds was also employed as thresholds at the subwatershed and watershed scales. The thresholds of CAP for P and I30 were 50.5% and 47.6% at the subwatershed scale, while 31.0% and 30.3% at the watershed scale. The thresholds of P and I30 at the subwatershed scale were higher than those of hillslope scale, while the threshold of I30 at the watershed scale was smaller compared to the other scales. In general, I30 was viewed as the best threshold among single rainfall indexes across different spatial scales, while P was not recommended as a practical threshold. This study can improve the prediction accuracy of water erosion across different spatial scales and develop the spatial scale effect of sediment yield in the loess hilly areas.

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Sediment Yield in Dam-Controlled Watersheds in the Pisha Sandstone Region on the Northern Loess Plateau, China

Land ◽

10.3390/land10111264 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1264

Author(s):

Fabing Xie ◽

Guangju Zhao ◽

Xingmin Mu ◽

Peng Tian ◽

Peng Gao ◽

...

Keyword(s):

Soil Erosion ◽

Loess Plateau ◽

Sediment Yield ◽

Water Conservation ◽

The Loess Plateau ◽

Sediment Yields ◽

Erosion Rates ◽

Soil Erosion Rate ◽

Check Dams ◽

Loss Control

Soil erosion has become the dominant environmental issue endangering sustainable development in agriculture and the ecosystem on the Loess Plateau. Determination of watershed soil erosion rates and sediment yields is essential for reasonable utilization of water resources and soil loss control. In this study, we employed unmanned aerial vehicles (UAVs) and structure-from-motion (SfM) photogrammetry to determine the sediment yields in 24 dam-controlled watersheds in the Pisha sandstone region of the northern Loess Plateau. High differences in total sediment were trapped before the check dams due to their running periods and sediment yields. The estimated specific sediment yield ranged from 34.32 t/(ha∙a) to 123.80 t/(ha∙a) with an average of 63.55 t/(ha∙a), which indicated that the Pisha sandstone region had an intense soil erosion rate. Furthermore, the modified Sediment Distributed Delivery (SEDD) model was applied to identify the erosion-prone areas in the watersheds, and the sediment retained in the check dams were used for model calibration. The performance of the model was acceptable, and the modeling results indicated that the steep Pisha sandstone was the major sediment source for the watersheds, accounting for approximately 87.37% of the sediment yield. Catchment area, erosive precipitation, and badland proportion were the key factors for sediment yield in the dam-controlled watersheds of the Pisha sandstone region, according to multiple regression analyses. These findings indicated that the modified SEDD model is very efficient in identifying spatial heterogeneities of sediment yield in the watershed but requires comprehensive calibration and validation with long-term observations. The Pisha sandstone region is still the key area of soil erosion control in the Loess Plateau, which needs more attention for soil and water conservation due to high sediment yield.

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A New Method for Computing the Sediment Delivery Ratio for the Hyper-Concentrated Flow Areas of the Loess Plateau, China

Journal of Environmental Informatics ◽

10.3808/jei.202100456 ◽

2021 ◽

Author(s):

T. H. Li ◽

◽

W. C. Xie ◽

◽

...

Keyword(s):

Loess Plateau ◽

New Method ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

The Loess Plateau ◽

Sediment Delivery ◽

Concentrated Flow

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Interactive Discussion Comments "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"

10.5194/hess-2016-654-rc2 ◽

2017 ◽

Author(s):

Anonymous

Keyword(s):

Land Use ◽

Loess Plateau ◽

Sediment Yield ◽

Temporal Patterns ◽

Precipitation Variability ◽

The Loess Plateau ◽

Long Term Changes ◽

Spatio Temporal

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Effect of vegetation on runoff-sediment yield relationship at different spatial scales in hilly areas of the Loess Plateau, North China

Acta Ecologica Sinica ◽

10.1016/s1872-2032(07)60075-4 ◽

2007 ◽

Vol 27 (9) ◽

pp. 3572-3581 ◽

Cited By ~ 34

Author(s):

Zheng Mingguo ◽

Cai Qiangguo ◽

Chen Hao

Keyword(s):

Loess Plateau ◽

Sediment Yield ◽

North China ◽

Spatial Scales ◽

The Loess Plateau ◽

Runoff Sediment

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Prediction of Sediment Yield in the Middle Reaches of the Yellow River Basin Under Extreme Precipitation

Frontiers in Earth Science ◽

10.3389/feart.2020.542686 ◽

2020 ◽

Vol 8 ◽

Author(s):

Suzhen Dang ◽

Xiaoyan Liu ◽

Huijuan Yin ◽

Xinwei Guo

Keyword(s):

River Basin ◽

Loess Plateau ◽

Sediment Yield ◽

Extreme Precipitation ◽

Land Surface ◽

Yellow River ◽

Yellow River Basin ◽

The Yellow River ◽

The Loess Plateau ◽

The Yellow River Basin

The Yellow River is one of the rivers with the largest amount of sediment in the world. The amount of incoming sediment has an important impact on water resources management, sediment regulation schemes, and the construction of water conservancy projects. The Loess Plateau is the main source of sediment in the Yellow River Basin. Floods caused by extreme precipitation are the primary driving forces of soil erosion in the Loess Plateau. In this study, we constructed the extreme precipitation scenarios based on historical extreme precipitation records in the main sediment-yielding area in the middle reaches of the Yellow River. The amount of sediment yield under current land surface conditions was estimated according to the relationship between extreme precipitation and sediment yield observations in the historical period. The results showed that the extreme rainfall scenario of the study area reaches to 159.9 mm, corresponding to a recurrence period of 460 years. The corresponding annual sediment yield under the current land surface condition was range from 0.821 billion tons to 1.899 billion tons, and the median annual sediment yield is 1.355 billion tons, of which more than 91.9% of sediment yields come from the Hekouzhen to Longmen sectionand the Jinghe River basin. Therefore, even though the vegetation of the Loess Plateau has been greatly improved, and a large number of terraces and check dams have been built, the flood control and key project operation of the Yellow River still need to be prepared to deal with the large amount of sediment transport.

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