Do deterministic sediment detachment and transport equations adequately represent the process-interactions in eroding rills? An experimental field study

Wirtz, Stefan; Seeger, Manuel; Remke, Alexander; Wengel, R.; Wagner, Jean-Frank; Ries, Johannes B.

doi:10.1016/j.catena.2012.10.003

Cited by 25 publications

(9 citation statements)

References 105 publications

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“…Unit stream power has also been identified as a good hydraulic parameter for describing the soil detachment rate (De Roo, Wesselling, & Ritsema, ; Govers, ). Wirtz et al () observed a nonlinear relationship between shear stress and soil detachment. However, most of these results were obtained in studies that inadequately reflected the true detachment process of concentrated flow on slope during rill development by limiting width development as noted above.…”

Section: Introductionmentioning

confidence: 99%

“…However, real rills have a rough irregular bed with headcuts, knickpoints, and sinuosity (Giménez & Govers, ; Shen, Zheng, Wen, Lu, & Jiang, ). Therefore, many subprocesses during rill development, such as headcut erosion, sidewall failure, tunneling, micropiping, slaking, piping, and sapping dynamics (Wirtz et al, ; Zhang, Li, & Ding, ), were restricted in previous studies. These subprocesses probably caused a significant amount of soil loss during rill development (Stefanovic & Bryan, ).…”

Section: Introductionmentioning

confidence: 99%

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Response of soil detachment rate to the hydraulic parameters of concentrated flow on steep loessial slopes on the Loess Plateau of China

Xiao

Liu

et al. 2017

Hydrological Processes

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Using hydraulic parameters is essential for describing soil detachment and developing physically based erosion prediction models. Many hydraulic parameters have been used, but the one that performs the best for describing soil detachment on steep slopes when the lateral expansion (widening) of rills is not limited has not been identified. An indoor concentrated flow scouring experiment was performed on steep loessial slopes to investigate soil detachment rates for different flow rates and slope gradients. The experiments were conducted on a slope‐adjustable plot (5 m length, 1 m width, 0.5 m depth). Sixteen combinations of 4 flow rates (10, 15, 20, and 25 L/min) and 4 slope gradients (17.6%, 26.8%, 36.4%, and 46.6%) were investigated. The individual and combined effects of slope gradient and flow hydraulic parameters on soil detachment rate were analysed. The results indicated that soil detachment rate increased with flow rate and slope gradient. Soil detachment rate varied linearly and exponentially with flow rate and slope gradient, respectively. Multivariate, nonlinear regression analysis indicated that flow depth exerted the greatest influence on the soil detachment rate, followed by unit discharge per unit width, slope gradient, and flow rate in this study. Shear stress and stream power could efficiently describe the soil detachment rate using a power equation. However, the unit stream power and unit energy of the water‐carrying section changed linearly with soil detachment rate. Stream power was an optimal hydraulic parameter for describing soil detachment. These findings improve our understanding of concentrated flow erosion on steep loessial slopes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Response of soil detachment rate to the hydraulic parameters of concentrated flow on steep loessial slopes on the Loess Plateau of China

Xiao

Liu

et al. 2017

Hydrological Processes

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“…Rill development is a result of the detachment of soil particles by rill flow, which transports not only rill flow‐detached particles but also those delivered from interrill areas. Therefore, it is important to explicitly distinguish rill flow from interrill flow in hill slope runoff models, particularly in models used to predict soil loss (Nearing et al , ; Elliot and Laflen, ; Huang et al , ; Wirtz et al , ). Although significant previous research efforts have focused on models of interrill erosion (Young and Onstad, ; Nearing et al , ; Huang, ,; Zhang, ), there is limited knowledge about the mechanisms of rill erosion despite the greater erosion contribution of rill erosion compared with interrill erosion where rill erosion occurs (Rejman and Brodowski, ; Bruno et al , ; Wirtz et al , ; Di Stefano et al , ), particularly on steep slopes, where rill development is rapid and unstable in channel shape.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic characteristics of rill flow on steep slopes

Wen-ying

Zhang

2015

Hydrological Processes

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Abstract:Rill erosion is a dominant sediment source on sloping lands. However, the amount of soil loss from rills on steep slopes is vastly more than that on gentle slopes because of differences in rill shape and hydraulic patterns. The aims of this paper are to determine the hydrodynamic characteristics of rills and the friction coefficients in steep slope conditions and to propose modifications of some hydraulic parameters used in soil loss prediction models. A series of inflow experiments was conducted on loess slopes. The results show that the geometric and hydraulic properties of rill on the steep loess slopes, which are characterized by the mean width of cross sections, mean velocity and mean depth of flow, are related to discharge and slope gradient in power functions. However, the related exponents to discharge are 0.26, 0.48 and 0.26, respectively, which are different from the exponents derived in previous studies, which were conducted on gentle slopes. The Manning roughness coefficient ranged from 0.035 to 0.071, with an average of 0.0536, and the Darcy-Weisbach friction coefficients varied from 0.4 to 1.9. The roughness coefficients are closely related to the Reynolds numbers and flow volumes; however, the correlations vary with slope gradient. The roughness coefficients are directly proportional to the Reynolds number and the flow volume on steep slopes, in contrast with the roughness coefficients found on gentle slopes, which decrease as the Reynolds number and flow volume increase. This difference is caused by the interactions among the hydraulics of the flow, the shape of the rills and the sediment concentrations on steep slopes. The results indicate that parameters used in models to predict rill erosion have to be modified according to slope gradient.

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“…Some unanswered questions regarding splash erosion are how it interacts with other processes such as infiltration, soil water repellency or how soil structure and composition change in relation with raindrop impacts (Wirtz et al, 2013). This lack of understanding contributes to the limited knowledge we have about the full cascade of erosion processes and how they interact with one another.…”

Section: Main Gaps In Splash Erosion Researchmentioning

confidence: 99%

Splash erosion: A review with unanswered questions

Fernández‐Raga

Palencia

Keesstra

et al. 2017

Earth-Science Reviews

182

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Soil erosion is a serious ecological and environmental problem, and the main cause of land degradation in many ecosystems at global scale. Detachment of soil particles by raindrop splash is the first stage in the soil erosion process. A review of the scientific literature published in peer-reviewed international journals (ISI) over the last decades on splash erosion research sheds light on the current scientific knowledge on this topic. In addition, it highlights the research gaps and unanswered questions in our understanding of soil erosion processes due to splash. In this literature review, a bibliographic search in Web of Science by the Institute for Scientific Information (ISI) database was carried out on August the 9th, 2016, that returned 669 papers containing the words "splash erosion". The research found was categorised according to a number of criteria: i) devices used to measure splash erosion, ii) advantages and disadvantages of these devices, iii) splash erosion studies by country, iv) date of publication of the first article, v) evolution of the number of articles published in each ten-year period, vi) concepts studied, vii) keywords, viii) authors, ix) number of citations, and x) most cited articles. After this review a synthesis of the information that the science has published about splash erosion was made in order to improve our understanding about splash erosion, by identifying the research questions that still remain unanswered today about the first detachment mechanism. From this review several issues were found important for the advancement of this research topic: a) further study of the known basic factors influencing splash erosion; b) description and quantification of sources of uncertainty about the measurement of different variables; c) to understand the influences that the chosen research approach by individual researchers will have in the final result; and, d) to study the impact of drivers or mitigation techniques that may affect splash erosion.

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Do deterministic sediment detachment and transport equations adequately represent the process-interactions in eroding rills? An experimental field study

Cited by 25 publications

References 105 publications

Response of soil detachment rate to the hydraulic parameters of concentrated flow on steep loessial slopes on the Loess Plateau of China

Response of soil detachment rate to the hydraulic parameters of concentrated flow on steep loessial slopes on the Loess Plateau of China

Hydrodynamic characteristics of rill flow on steep slopes

Splash erosion: A review with unanswered questions

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