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Tammo S Steenhuis - One of the best experts on this subject based on the ideXlab platform.
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bank stability and toe Erosion Model as a decision tool for gully bank stabilization in sub humid ethiopian highlands
Ecohydrology and Hydrobiology, 2020Co-Authors: Assefa D. Zegeye, Tammo S Steenhuis, Eddy J Langendoen, Wolde Mekuria, Seifu A. TilahunAbstract:Abstract Gullies that are expanding at alarming rate are responsible for the majority of soil losses in the (sub) humid highlands of Ethiopia. Few affordable and effective methods for gully Erosion control are available in the highlands. The objective of the study was to develop cost-effective measures to halt gully expansion by determining stable-bank conditions under a variety of environmental situations using the Bank Stability and Toe Erosion Model (BSTEM). The study was carried out in the sub humid Debre Mawi watershed, located 30 km south of Lake Tana. Input data for the BSTEM Model were collected using field surveys and soil sampling. After the BSTEM was tested on actual measured soil data, soil cohesion and internal friction angle were calibrated against observed gully bank retreat. Using the calibrated parameters, the Model evaluated the stabilization of the existing gully bank under different scenarios in which groundwater table, bank angle and bank height, tension crack depth, vegetation, and toe protection were varied. Finally, the head-cut of the study gully was treated based on the Model recommendation. The simulated results showed that a 5 m deep gully was stable under fully saturated conditions when the bank toe is protected, its upper surface is vegetated, and its bank angles do not exceed 45°. If the depth of the gully is less than 5 m or if its water table is deeper than 0.5 m, only regrading the gully bank to an angle of 45° can stabilize the gully. BSTEM showed to be an effective tool that can be used to evaluate gully control measures.
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an efficient semi distributed hillslope Erosion Model for the subhumid ethiopian highlands
Hydrology and Earth System Sciences, 2013Co-Authors: Seifu A. Tilahun, T. A. Engda, Christian D. Guzman, Amy S. Collick, Assefa D. Zegeye, Alon Rimmer, Tammo S SteenhuisAbstract:Abstract. Erosion Modeling has been generally scaling up from plot scale but not based on landscape topographic position, which is a main variable in saturation excess runoff. In addition, predicting sediment loss in Africa has been hampered by using Models developed in western countries and do not perform as well in the monsoon climate prevailing in most of the continent. The objective of this paper is to develop a simple Erosion Model that can be used in the Ethiopian Highlands in Africa. We base our sediment prediction on a simple distributed saturated excess hydrology Model that predicts surface runoff from severely degraded lands and from bottom lands that become saturated during the rainy season and estimates interflow and baseflow from the remaining portions of the landscape. By developing an equation that relates surface runoff to sediment concentration generated from runoff source areas, assuming that baseflow and interflow are sediment-free, we were able to predict daily sediment concentrations from the Anjeni watershed with a Nash–Sutcliffe efficiency ranging from 0.64 to 0.78 using only two calibrated sediment parameters. Anjeni is a 113 ha watershed in the 17.4 million ha Blue Nile Basin in the Ethiopian Highlands. The discharge of the two watersheds was predicted with Nash–Sutcliffe efficiency values ranging from 0.80 to 0.93. The calibrated values in Anjeni for degraded (14%) and saturated (2%) runoff source area were in agreement with field evidence. The analysis suggests that identifying the runoff source areas and predicting the surface runoff correctly is an important step in predicting the sediment concentration.
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investigating ponding depth and soil detachability for a mechanistic Erosion Model using a simple experiment
Journal of Hydrology, 2003Co-Authors: Bin Gao, Tammo S Steenhuis, M T Walter, Jeanyves Parlange, K Nakano, C W Rose, W L HogarthAbstract:This work extends the simple experimental studies initiated by Heilig et al. [J. Hydrol. 244(2001) 9] to study Erosion processes inherent to a mechanistic soil Erosion Model (the Rose Model) that were not addressed in earlier studies. Specifically, we investigated the impacts of ponding water depth and soil detachability on Erosion. The Rose Model describes the interplay among the processes of soil detachment, transport, deposition, and redetachment, which are involved in rain-induced soil Erosion and sediment transport. The simple experiment that was used to improve our understanding of how water-ponding and soil detachability affect soil Erosion utilized a small, horizontal, uniform, soil surface exposed to uniform, simulated rainfall. Rainfall rates were systematically changed between 6 and 48 mm h 21 . Soil detachability was associated with a clay soil prepared at two different water contents. The Rose Model was applied to the experimental conditions and the predicted Erosion behavior was compared to experimental measurements. Observed data compared very well with the Model results. The experimentally observed relationship between ponding water depth and soil detachability agreed well with previously proposed theories; soil detachability was constant for ponding depths below a critical depth and dramatically decreased above the critical depth. Also, these experiments corroborated that the soil detachability as represented in the Rose Model is independent of rain intensity. These results provide support to the validity of the Rose Model with respect to the roles of surface water-ponding and its relationship to soil detachability. These mechanisms can be incorporated into Models of more complicated and realistic systems in which these individual processes may be difficult to explicitly identify. q 2003 Elsevier Science B.V. All rights reserved.
Seifu A. Tilahun - One of the best experts on this subject based on the ideXlab platform.
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bank stability and toe Erosion Model as a decision tool for gully bank stabilization in sub humid ethiopian highlands
Ecohydrology and Hydrobiology, 2020Co-Authors: Assefa D. Zegeye, Tammo S Steenhuis, Eddy J Langendoen, Wolde Mekuria, Seifu A. TilahunAbstract:Abstract Gullies that are expanding at alarming rate are responsible for the majority of soil losses in the (sub) humid highlands of Ethiopia. Few affordable and effective methods for gully Erosion control are available in the highlands. The objective of the study was to develop cost-effective measures to halt gully expansion by determining stable-bank conditions under a variety of environmental situations using the Bank Stability and Toe Erosion Model (BSTEM). The study was carried out in the sub humid Debre Mawi watershed, located 30 km south of Lake Tana. Input data for the BSTEM Model were collected using field surveys and soil sampling. After the BSTEM was tested on actual measured soil data, soil cohesion and internal friction angle were calibrated against observed gully bank retreat. Using the calibrated parameters, the Model evaluated the stabilization of the existing gully bank under different scenarios in which groundwater table, bank angle and bank height, tension crack depth, vegetation, and toe protection were varied. Finally, the head-cut of the study gully was treated based on the Model recommendation. The simulated results showed that a 5 m deep gully was stable under fully saturated conditions when the bank toe is protected, its upper surface is vegetated, and its bank angles do not exceed 45°. If the depth of the gully is less than 5 m or if its water table is deeper than 0.5 m, only regrading the gully bank to an angle of 45° can stabilize the gully. BSTEM showed to be an effective tool that can be used to evaluate gully control measures.
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an efficient semi distributed hillslope Erosion Model for the subhumid ethiopian highlands
Hydrology and Earth System Sciences, 2013Co-Authors: Seifu A. Tilahun, T. A. Engda, Christian D. Guzman, Amy S. Collick, Assefa D. Zegeye, Alon Rimmer, Tammo S SteenhuisAbstract:Abstract. Erosion Modeling has been generally scaling up from plot scale but not based on landscape topographic position, which is a main variable in saturation excess runoff. In addition, predicting sediment loss in Africa has been hampered by using Models developed in western countries and do not perform as well in the monsoon climate prevailing in most of the continent. The objective of this paper is to develop a simple Erosion Model that can be used in the Ethiopian Highlands in Africa. We base our sediment prediction on a simple distributed saturated excess hydrology Model that predicts surface runoff from severely degraded lands and from bottom lands that become saturated during the rainy season and estimates interflow and baseflow from the remaining portions of the landscape. By developing an equation that relates surface runoff to sediment concentration generated from runoff source areas, assuming that baseflow and interflow are sediment-free, we were able to predict daily sediment concentrations from the Anjeni watershed with a Nash–Sutcliffe efficiency ranging from 0.64 to 0.78 using only two calibrated sediment parameters. Anjeni is a 113 ha watershed in the 17.4 million ha Blue Nile Basin in the Ethiopian Highlands. The discharge of the two watersheds was predicted with Nash–Sutcliffe efficiency values ranging from 0.80 to 0.93. The calibrated values in Anjeni for degraded (14%) and saturated (2%) runoff source area were in agreement with field evidence. The analysis suggests that identifying the runoff source areas and predicting the surface runoff correctly is an important step in predicting the sediment concentration.
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A Saturation Excess Erosion Model
Transactions of the ASABE, 2013Co-Authors: Seifu A. Tilahun, Rajith Mukundan, Bezawit A. Demisse, T. A. Engda, Christian D. Guzman, Birara C. Tarakegn, Zachary M. Easton, Amy S. Collick, Assefa D. Zegeye, Elliot M. SchneidermanAbstract:Abstract. Scaling-up sediment transport has been problematic because most sediment loss Models (e.g., the Universal Soil Loss Equation) are developed using data from small plots where runoff is generated by infiltration excess. However, in most watersheds, runoff is produced by saturation excess processes. In this article, we improve an earlier saturation excess Erosion Model that was only tested on a limited basis, in which runoff and Erosion originated from periodically saturated and severely degraded areas, and apply it to five watersheds over a wider geographical area. The Erosion Model is based on a semi-distributed hydrology Model that calculates saturation excess runoff, interflow, and baseflow. In the development of the Erosion Model, a linear relationship between sediment concentration and velocity in surface runoff is assumed. Baseflow and interflow are sediment free. Initially during the rainy season in Ethiopia, when the fields are being plowed, the sediment concentration in the river is limited by the ability of the surface runoff to move sediment. Later in the season, the sediment concentration becomes limited by the availability of sediment. To show the general applicability of the Saturation Excess Erosion Model (SEEModel), the Model was tested for watersheds located 10,000 km apart, in the U.S. and in Ethiopia. In the Ethiopian highlands, we simulated the 1.1 km 2 Anjeni watershed, the 4.8 km 2 Andit Tid watershed, the 4.0 km 2 Enkulal watershed, and the 174,000 km 2 Blue Nile basin. In the Catskill Mountains in New York State, the sediment concentrations were simulated in the 493 km 2 upper Esopus Creek watershed. Discharge and sediment concentration averaged over 1 to 10 days were well simulated over the range of scales with comparable parameter sets. The Nash-Sutcliffe efficiency (NSE) values for the validation runs for the stream discharge were between 0.77 and 0.92. Sediment concentrations had NSE values ranging from 0.56 to 0.86 using only four calibrated sediment parameters together with the subsurface and surface runoff discharges calculated by the hydrology Model. The Model results suggest that correctly predicting both surface runoff and subsurface flow is an important step in simulating sediment concentrations.
Yves Le Bissonnais - One of the best experts on this subject based on the ideXlab platform.
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Local sensitivity analysis of the Landsoil Erosion Model applied to a virtual catchment
2016Co-Authors: Rossano Ciampalini, Yves Le Bissonnais, Stéphane Follain, Bruno Cheviron, A. Couturier, Roger Moussa, C. WalterAbstract:This book chapter describes the main features of the Landsoil Erosion Model then investigates the sensitivity of its key parameters by local (one-at-a-time) methods. A virtual catchment is used to represented numerous characteristic distributions of site properties with respect to water and sediment fluxes.
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MHYDAS-Erosion: a distributed single-storm water Erosion Model for agricultural catchments
Hydrological Processes, 2011Co-Authors: Silvio José Gumière, Damien Raclot, Bruno Cheviron, Roger Moussa, Grégory Davy, Xavier Louchart, Jean-christophe Fabre, Yves Le BissonnaisAbstract:In this paper, we present MHYDAS-Erosion, a dynamic and distributed single-storm water Erosion Model developed as a module of the existing hydrological MHYDAS Model. As with many catchment Erosion Models, MHYDAS-Erosion is able to simulate sediment transport, Erosion and deposition by rill and interrill processes. Its originality stems from its capacity to integrate the impact of land management practices (LMP) as key elements controlling the sedimentological connectivity in agricultural catchments. To this end, the water-sediment pathways are first determined by a specific process-oriented procedure defined and controlled by the user, which makes the integration of LMP easier. The LMP dynamic behaviours are then integrated into the Model as a time-dependent function of hydrological variables and LMP characteristics. The first version of the Model was implemented for vegetative filters and tested using water and sediment discharge measurements at three nested scales of a densely instrumented catchment (Roujan, OMERE Observatory, southern France). The results of discharge and soil loss for simulated rainfall events have been found to acceptably compare with available data. The average R(2) values for water and sediment discharge are 0.82 and 0.83, respectively. The sensitivity of the Model to changes in the proportion of LMP was assessed for a single rain event by considering three scenarios of the Roujan catchment management with vegetative filters: 0% (Scenario 1), 18% (Scenario 2, real case) and 100% (Scenario 3). Compared to Scenario 2 (real case), soil losses decreased for Scenario 3 by 65% on the agricultural plot scale, 62% on the sub-catchment scale and 45% at the outlet of the catchment and increased for Scenario 1 by 0% on the plot scale, 26% on the sub-catchment scale and 18% at the outlet of the catchment.
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Soil resistance to interrill Erosion: Model parameterization and sensitivity
CATENA, 2009Co-Authors: Silvio José Gumière, Yves Le Bissonnais, Damien RaclotAbstract:Abstract Interrill Erosion, which is less visible in the landscape than rill and gully Erosion, may cause major sediment deposits in the lower part of cultivated fields. It is often associated with runoff resulting from sealing and crusting, and soil properties such as soil detachability or soil aggregate stability have been used to express soil resistance to interrill Erosion processes, i.e., interrill erodibility. From a literature review including more than fifteen Erosion Models, we have identified three main methods used to measure these properties: aggregate stability and splash cup detachability, methods performed in the laboratory using only a few grams of soil, and standard plot methods that are based on field plot measurements. This difference makes the parameters involved in assessing interrill erodibility dependent upon the scale and the hydrological processes involved and difficult to compare. According to the literature, the sensitivity of actual Erosion Models to interrill erodibility is lower than the sensitivity to hydrological properties and rill erodibility parameters. This numerical study shows that erodibility measurements from the three major assessment methods give different results regarding the contribution of interrill Erosion and show that the sensitivity of Erosion Modeling to interrill erodibility may in fact be greater than shown in the literature on global sensitivity analysis.
Anish Khanal - One of the best experts on this subject based on the ideXlab platform.
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evaluating a process based Model for use in streambank stabilization insights on the bank stability and toe Erosion Model bstem
Earth Surface Processes and Landforms, 2017Co-Authors: Kate Klavon, Eddy J Langendoen, Garey A Fox, Lucie Guertault, Holly K Enlow, Ronald B Miller, Anish KhanalAbstract:Streambank retreat is a complex cyclical process involving subaerial processes, fluvial Erosion, seepage Erosion, and geotechnical failures and is driven by several soil properties that themselves are temporally and spatially variable. Therefore, it can be extremely challenging to predict and Model the Erosion and consequent retreat of streambanks. However, Modeling streambank retreat has many important applications, including the design and assessment of mitigation strategies for stream revitalization and stabilization. In order to highlight the current complexities of Modeling streambank retreat and to suggest future research areas, this paper reviewed one of the most comprehensive streambank retreat Models available, the Bank Stability and Toe Erosion Model (BSTEM), which has recently been integrated with several popular hydrodynamic and sediment transport Models including HEC-RAS. The objectives of this paper were to: (i) comprehensively review studies that have utilized BSTEM and report their findings, (ii) address the limitations of the Model so that it can be applied appropriately in its current form, and (iii) suggest directions of research that will help make the Model a more useful tool in future applications. The paper includes an extensive overview of peer reviewed studies to guide future users of BSTEM. The review demonstrated that the Model needs further testing and evaluation outside of the central United States. Also, further development is needed in terms of accounting for spatial and temporal variability in geotechnical and fluvial erodibility parameters, incorporating subaerial processes, and accounting for the influence of riparian vegetation on streambank pore-water pressure dynamics, applied shear stress, and erodibility parameters. This article is protected by copyright. All rights reserved.
Garey A Fox - One of the best experts on this subject based on the ideXlab platform.
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evaluating a process based Model for use in streambank stabilization insights on the bank stability and toe Erosion Model bstem
Earth Surface Processes and Landforms, 2017Co-Authors: Kate Klavon, Eddy J Langendoen, Garey A Fox, Lucie Guertault, Holly K Enlow, Ronald B Miller, Anish KhanalAbstract:Streambank retreat is a complex cyclical process involving subaerial processes, fluvial Erosion, seepage Erosion, and geotechnical failures and is driven by several soil properties that themselves are temporally and spatially variable. Therefore, it can be extremely challenging to predict and Model the Erosion and consequent retreat of streambanks. However, Modeling streambank retreat has many important applications, including the design and assessment of mitigation strategies for stream revitalization and stabilization. In order to highlight the current complexities of Modeling streambank retreat and to suggest future research areas, this paper reviewed one of the most comprehensive streambank retreat Models available, the Bank Stability and Toe Erosion Model (BSTEM), which has recently been integrated with several popular hydrodynamic and sediment transport Models including HEC-RAS. The objectives of this paper were to: (i) comprehensively review studies that have utilized BSTEM and report their findings, (ii) address the limitations of the Model so that it can be applied appropriately in its current form, and (iii) suggest directions of research that will help make the Model a more useful tool in future applications. The paper includes an extensive overview of peer reviewed studies to guide future users of BSTEM. The review demonstrated that the Model needs further testing and evaluation outside of the central United States. Also, further development is needed in terms of accounting for spatial and temporal variability in geotechnical and fluvial erodibility parameters, incorporating subaerial processes, and accounting for the influence of riparian vegetation on streambank pore-water pressure dynamics, applied shear stress, and erodibility parameters. This article is protected by copyright. All rights reserved.
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evaluation of the bank stability and toe Erosion Model bstem for predicting lateral retreat on composite streambanks
Geomorphology, 2012Co-Authors: Taber L Midgley, Garey A Fox, Derek M HeerenAbstract:Abstract Streambank Erosion is known to be a major source of sediment in streams and rivers. The Bank Stability and Toe Erosion Model (BSTEM) was developed in order to predict streambank retreat due to both fluvial Erosion and geotechnical failure. However, few, if any, Model evaluations using long-term streambank retreat data have been performed. The objectives of this research were to (1) monitor long-term composite streambank retreat during a hydraulically active period on a rapidly migrating stream, (2) evaluate BSTEM's ability to predict the measured streambank retreat, and (3) assess the importance of accurate geotechnical, fluvial Erosion, and near-bank pore-water pressure properties. The Barren Fork Creek in northeastern Oklahoma laterally eroded 7.8 to 20.9 m along a 100-m length of stream between April and October 2009 based on regular bank location surveys. The most significant lateral retreat occurred in mid- to late-May and September due to a series of storm events, and not necessarily the most extreme events observed during the monitoring period. BSTEM (version 5.2) was not originally programmed to run multiple hydrographs iteratively, so a subroutine was written that automatically input the temporal sequence of stream stage and to lag the water table in the near-bank ground water depending on user settings. Eight BSTEM simulations of the Barren Fork Creek streambank were performed using combinations of the following input data: with and without a water table lag; default BSTEM geotechnical parameters (moderate silt loam) versus laboratory measured geotechnical parameters based on direct shear tests on saturated soil samples; and default BSTEM fluvial Erosion parameters versus field measured fluvial Erosion parameters from submerged jet tests. Using default BSTEM input values underestimated the actual Erosion that occurred. Lagging the water table predicted more geotechnical failures resulting in greater streambank retreat. Using measured fluvial and geotechnical parameters and a water table lag also under predicted retreat (approximately 3.3 m), but did predict the appropriate timing of streambank collapses. The under prediction of retreat was hypothesized to be due to over predicting the critical shear stress of the non-cohesive gravel, under predicting the erodibility of the non-cohesive gravel, and/or under predicting the imposed shear stress acting on the streambank. Current research improving our understanding of shear stress distributions, streambank pore-water pressure dynamics, and methods for estimating excess shear stress parameters for noncohesive soils will be critical for improving BSTEM and other streambank stability Models.