Yuanyuan Zhang
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Yuanyuan Zhang has a total of 20 co-authors. Here are the top co-authors by number of shared publications:
- Jianen Gao
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China
4 shared publications - Zhe Gao
College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, China
3 shared publications - Genguang Zhang
College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, China
2 shared publications - Qianqian Ji
Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Xianyang 712100, China
2 shared publications - Rafiq Ahmad
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China
2 shared publications - Anbin Li
Department of Civil and Environmental Engineering, The University of Auckland, Auckland, New Zealand
1 shared publication
Latest Publications
- Open Access
Effect of Nitrogen on the Viscosity of the Erosive Sediment-Laden Flows
Viscosity is a fundamental hydrodynamic property of erosive flow, but except for the effect of sediment on viscosity, the effect of other erosive substances such as agricultural nitrogen on the characteristics of erosive flow has rarely been studied. This in turn is likely to be an important factor affecting the erosive transport mechanism. In this study, the effect of nitrogen on the viscosity of sediment-laden flow with different levels was investigated by using a self-made dual vertical tube rheometer. It was found that: (i) the viscosity coefficient (μ) of nitrogen-bearing erosive flow is affected by the nitrogen concentration, sediment content, and the physical and chemical properties of the sediment; (ii) the calculation model of the relative viscosity coefficient with the effects of nitrogen, concentration, sediment gradation, and temperature, was constructed, and the validation showed that the model not only has a clear physical meaning but also has a simple calculation method and good calculation accuracy. The results of the study are of great significance for the in-depth understanding of the erosion transport mechanism of erosive flow.
Open AccessEffect of Nitrogen on the Viscosity of the Erosive Sediment-Laden Flows
Viscosity is a fundamental hydrodynamic property of erosive flow, but except for the effect of sediment on viscosity, the effect of other erosive substances such as agricultural nitrogen on the characteristics of erosive flow has rarely been studied. This in turn is likely to be an important factor affecting the erosive transport mechanism. In this study, the effect of nitrogen on the viscosity of sediment-laden flow with different levels was investigated by using a self-made dual vertical tube rheometer. It was found that: (i) the viscosity coefficient (μ) of nitrogen-bearing erosive flow is affected by the nitrogen concentration, sediment content, and the physical and chemical properties of the sediment; (ii) the calculation model of the relative viscosity coefficient with the effects of nitrogen, concentration, sediment gradation, and temperature, was constructed, and the validation showed that the model not only has a clear physical meaning but also has a simple calculation method and good calculation accuracy. The results of the study are of great significance for the in-depth understanding of the erosion transport mechanism of erosive flow.
- Open Access
Erosion-Transportation Processes Influenced by Spatial Distribution of Terraces in Watershed in the Loess Hilly–Gully Region (LHGR), China
How to optimize the spatial distribution of terraces in the watershed is an important scientific problem. It was researched through a watershed solid-scale physical model based on the 3D reappearance of a scene under the Cartesian coordinate system, with the lowest point of the watershed as the origin. The results showed that the change of the spatial pattern of terraced fields in the basin had an important impact on the production of runoff and sediment. There was an approximate quadratic-function relationship between the spatial location and the parameters of runoff and confluence. If Rt was terrace-erosion-reduction benefit, it could be defined as the reduction in the watershed-erosion modulus per unit of terrace area. The longitudinal distribution of Rt was upper and middle > lower parts, and the vertical distribution of Rt was high > low place. The erosion reduction was 77.67% of the terraces of the middle and upper, occupying 33% of the watershed area. The change of the Rt was logarithmically related to the relative distance (r) from the center of the terrace. When r was around 0.35, there was an inflection point in Rt growth. The results of this study have important practical significance for the planning and construction of terraces in the watershed.
Open AccessErosion-Transportation Processes Influenced by Spatial Distribution of Terraces in Watershed in the Loess Hilly–Gully Region (LHGR), China
How to optimize the spatial distribution of terraces in the watershed is an important scientific problem. It was researched through a watershed solid-scale physical model based on the 3D reappearance of a scene under the Cartesian coordinate system, with the lowest point of the watershed as the origin. The results showed that the change of the spatial pattern of terraced fields in the basin had an important impact on the production of runoff and sediment. There was an approximate quadratic-function relationship between the spatial location and the parameters of runoff and confluence. If Rt was terrace-erosion-reduction benefit, it could be defined as the reduction in the watershed-erosion modulus per unit of terrace area. The longitudinal distribution of Rt was upper and middle > lower parts, and the vertical distribution of Rt was high > low place. The erosion reduction was 77.67% of the terraces of the middle and upper, occupying 33% of the watershed area. The change of the Rt was logarithmically related to the relative distance (r) from the center of the terrace. When r was around 0.35, there was an inflection point in Rt growth. The results of this study have important practical significance for the planning and construction of terraces in the watershed.
- Open Access
Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China
The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.Open AccessErosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China
The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW. - Open Access
Quantitative Analysis of Hydrological Responses to Climate Variability and Land-Use Change in the Hilly-Gully Region of the Loess Plateau, China
Climate and land-use change are the two main driving forces that affect watershed hydrological processes. Separately assessing their impacts on hydrology is important for land-use planning and water resource management. In this research, the SWAT (Soil and Water Assessment Tool) and statistical methods were applied to evaluate the effects of climate and land-use change on surface hydrology in the hilly-gully region of the Loess Plateau. The results showed that surface runoff and soil water presented a downward tendency, while evapotranspiration (ET) presented an upward tendency in the Yanhe watershed from 1982 to 2012. Climate is one the dominant factors that influence surface runoff, especially in flooding periods. The average contribution rate of surface runoff on stream flow accounted for 55%, of which the flooding period accounted for 40%. The runoff coefficient declined by 0.21 after 2002 with the land-use change of cropland transformed to grassland and forestland. The soil water exhibited great fluctuation along the Yanhe watershed. In the upstream region, the land-use was the driving force to decline soil water, which reduced the soil water by 51%. Along the spatial distribution, it converted from land-use change to climate variability from northwest to southeast. The ET was more sensitive to land-use change than climate variability in all sub-basins, and increased by 209% with vegetation restoration. To prevent the ecosystem degradation and maintain the inherent ecological functions of rivers, quantitative assessment the influence of climate variability and land-use change on hydrology is of great importance. Such evaluations can provide insight into the extent of land use/cover change on regional water balance and develop appropriate watershed management strategies on the Loess Plateau.
Open AccessQuantitative Analysis of Hydrological Responses to Climate Variability and Land-Use Change in the Hilly-Gully Region of the Loess Plateau, China
Climate and land-use change are the two main driving forces that affect watershed hydrological processes. Separately assessing their impacts on hydrology is important for land-use planning and water resource management. In this research, the SWAT (Soil and Water Assessment Tool) and statistical methods were applied to evaluate the effects of climate and land-use change on surface hydrology in the hilly-gully region of the Loess Plateau. The results showed that surface runoff and soil water presented a downward tendency, while evapotranspiration (ET) presented an upward tendency in the Yanhe watershed from 1982 to 2012. Climate is one the dominant factors that influence surface runoff, especially in flooding periods. The average contribution rate of surface runoff on stream flow accounted for 55%, of which the flooding period accounted for 40%. The runoff coefficient declined by 0.21 after 2002 with the land-use change of cropland transformed to grassland and forestland. The soil water exhibited great fluctuation along the Yanhe watershed. In the upstream region, the land-use was the driving force to decline soil water, which reduced the soil water by 51%. Along the spatial distribution, it converted from land-use change to climate variability from northwest to southeast. The ET was more sensitive to land-use change than climate variability in all sub-basins, and increased by 209% with vegetation restoration. To prevent the ecosystem degradation and maintain the inherent ecological functions of rivers, quantitative assessment the influence of climate variability and land-use change on hydrology is of great importance. Such evaluations can provide insight into the extent of land use/cover change on regional water balance and develop appropriate watershed management strategies on the Loess Plateau.