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Meander cutoffs and oxbow lakes are very common features of fluvial landscapes that add complexity and diversity to floodplain alluvial architecture and riverine habitats. Following initial cutoff, sediment accumulates within the entrance and exit of the original bend forming plugs that eventually disconnect the abandoned bend from the main channel. While studies have examined the sedimentology of these plugs once they have fully disconnected from the abandoned bend, fewer studies have detailed the sedimentological processes occurring during the early stages following cutoff initiation. Furthermore, recent studies have highlighted the importance that planform geometry plays in the evolution of neck cutoffs. This study examines the spatial depositional patterns of two neck cutoffs on the White River in central Arkansas, USA, that remain hydrologically connected to the main channel, providing a unique opportunity to research sedimentological processes before disconnection of the abandoned bend. Sediment cores were collected in key locations of each cutoff, including the entrance and exit of the abandoned bends, abandoned bend apices, and newly developed cutoff bars in the downstream channel. The cores were logged and interpreted and grain-size analyses were performed. In addition to sediment cores, repeat high-resolution multibeam echo sounding surveys were conducted roughly four hours apart to estimate bedload transport rates and patterns of bedload routing through each cutoff. Results from this research are different from previous studies. Sediment core results show a pattern of deposition typically associated with lower diversion angle chute cutoffs instead of higher diversion angle neck cutoffs. Previous research has indicated that plugging of abandoned bends drives disconnection from the active channel; however, this research shows that disconnection is more associated with the prevention of sediment from being delivered to the abandoned bends due to flow being pulled away from the abandoned bends and the evolving channel morphology.
Derek Richards; Kory Konsoer; Eddy Langendoen; Mick Ursic; José Constantine. Depositional patterns of slowly plugging neck cutoffs from core analysis and estimates of bedload transport, White River, Arkansas. Sedimentology 2021, 1 .
AMA StyleDerek Richards, Kory Konsoer, Eddy Langendoen, Mick Ursic, José Constantine. Depositional patterns of slowly plugging neck cutoffs from core analysis and estimates of bedload transport, White River, Arkansas. Sedimentology. 2021; ():1.
Chicago/Turabian StyleDerek Richards; Kory Konsoer; Eddy Langendoen; Mick Ursic; José Constantine. 2021. "Depositional patterns of slowly plugging neck cutoffs from core analysis and estimates of bedload transport, White River, Arkansas." Sedimentology , no. : 1.
It can be difficult to predict sediment transport in sand-bedded ephemeral streams because of rapidly changing conditions that may not be sustained long enough to reach equilibrium. This situation often leads to the inheritance of bed topography from previous flows, which may result in under- or overpredictions of transport rate due to bed forms and flow resistance that are not in equilibrium with the flow conditions. To address this difficulty, a series of lab experiments was used to examine changes in sediment transport rate and bed topography after rapid increases in flow depth and discharge. It was found that sand transport rates reached equilibrium conditions in as little as 1–15 min after the step-up in flow rate and depth. Transport rate equilibrium was likely reached in advance of centerline bed-form amplitude, although bed forms also responded quickly to step-up flows, and the response was much more rapid than in previous experiments that examined the effects of decreases in flow rate and depth.
Daniel G. Wren; Eddy J. Langendoen; Roger A. Kuhnle. Changes in Sediment Transport and Bed Topography in Response to Step-Up Flows in Laboratory Flume. Journal of Hydraulic Engineering 2021, 147, 06021002 .
AMA StyleDaniel G. Wren, Eddy J. Langendoen, Roger A. Kuhnle. Changes in Sediment Transport and Bed Topography in Response to Step-Up Flows in Laboratory Flume. Journal of Hydraulic Engineering. 2021; 147 (4):06021002.
Chicago/Turabian StyleDaniel G. Wren; Eddy J. Langendoen; Roger A. Kuhnle. 2021. "Changes in Sediment Transport and Bed Topography in Response to Step-Up Flows in Laboratory Flume." Journal of Hydraulic Engineering 147, no. 4: 06021002.
Mega-gullies and landslides pose significant hazards to urban development on steep terrain. Water resources infrastructure failures (WRIFs), such as leaks and breaks in water supply pipes, have been postulated as a trigger of mass movement events but data for validation has been challenging to acquire since earthwork proceeds quickly after events to repair roads and other infrastructure. Urban development in Tijuana, Mexico was monitored for a five-year period to document the occurrence of mega-gullies and landslides, including sediment volumes. A rapid assessment approach was developed based on photogrammetric observations from an unmanned aerial vehicle (UAV) and Structure from Motion (SfM) digital processing. Three hazardous mass-movement events were observed including two mega-gullies and one landslide. Furthermore, all three events were linked to WRIFs. Frequency analysis points to the annual probability of a WRIF-based erosion event in the range of 40–60 %, which is far higher than design levels typically used for urban stormwater infrastructure (5–10 %). Additionally, sediment modelling points to WRIF-based erosion as a non-negligible contributor to sediment generation. These results suggest that WRIFs are a significant contributor to erosion hazards facing urban development on steep terrain, and call for expanded monitoring to characterize the occurrence and modes of WRIF-based erosion events.
Napoleon Gudino-Elizondo; Matthew W. Brand; Trent W. Biggs; Alvaro Gomez-Gutierrez; Eddy Langendoen; Ronald Bingner; Yongping Yuan; Brett F. Sanders. Rapid assessment of urban mega-gully and landslide events with Structure-from-Motion techniques validates link to water resources infrastructure failures. 2021, 2021, 1 -22.
AMA StyleNapoleon Gudino-Elizondo, Matthew W. Brand, Trent W. Biggs, Alvaro Gomez-Gutierrez, Eddy Langendoen, Ronald Bingner, Yongping Yuan, Brett F. Sanders. Rapid assessment of urban mega-gully and landslide events with Structure-from-Motion techniques validates link to water resources infrastructure failures. . 2021; 2021 ():1-22.
Chicago/Turabian StyleNapoleon Gudino-Elizondo; Matthew W. Brand; Trent W. Biggs; Alvaro Gomez-Gutierrez; Eddy Langendoen; Ronald Bingner; Yongping Yuan; Brett F. Sanders. 2021. "Rapid assessment of urban mega-gully and landslide events with Structure-from-Motion techniques validates link to water resources infrastructure failures." 2021, no. : 1-22.
The US Department of Agriculture‐Agricultural Research Service’s (ARS) Experimental Watershed Network grew from Dust Bowl era efforts of the Soil Conservation Service in the mid 1930’s with the establishment of small experimental watersheds. In the 1950’s, five watershed research centers with intensively instrumented watersheds at the scale of 100 to 700 km2 were established. Primary network research objectives were to quantify on‐site and downstream effects of conservation practices and develop rainfall‐runoff relationships for design of water conservation structures. With passage of the Clean Water Act in 1972, research objectives have evolved to add a variety of observations relevant to the water quality issues. Many of the watersheds within the network have served, and continue to serve, as core validation sites for satellite sensors. As a result of the network’s long history and intensive monitoring, coupled with mission driven research, a deep knowledge base of watershed processes has been developed. This has led to the extensive development and validation of numerous watershed models that are in widespread use today. The visionary investments in building and maintaining this network and associated scientific investigations for more than half a century have not only resulted in numerous high impact research accomplishments but also a wide array of accomplishments that directly benefit society. The ARS Experimental Watersheds formed the core of the Conservation Effects Assessment Project (CEAP) as well as the recently established Long‐Term Agroecosystem Research (LTAR) Network. LTAR will expand the mission of the ARS Watersheds Network to include agricultural intensification, maintaining or improving ecosystem services while enhancing rural prosperity.
D. C. Goodrich; P. Heilman; M. Anderson; C. Baffaut; J. Bonta; D. Bosch; R. Bryant; M. Cosh; D. Endale; T. L. Veith; S. C. Havens; A. Hedrick; P. J. Kleinman; E. J. Langendoen; G. McCarty; T. Moorman; D. Marks; F. Pierson; J. R. Rigby; H. Schomberg; P. Starks; J. Steiner; T. Strickland; Teferi Tsegaye. The USDA‐ARS Experimental Watershed Network: Evolution, Lessons Learned, Societal Benefits, and Moving Forward. Water Resources Research 2021, 57, 1 .
AMA StyleD. C. Goodrich, P. Heilman, M. Anderson, C. Baffaut, J. Bonta, D. Bosch, R. Bryant, M. Cosh, D. Endale, T. L. Veith, S. C. Havens, A. Hedrick, P. J. Kleinman, E. J. Langendoen, G. McCarty, T. Moorman, D. Marks, F. Pierson, J. R. Rigby, H. Schomberg, P. Starks, J. Steiner, T. Strickland, Teferi Tsegaye. The USDA‐ARS Experimental Watershed Network: Evolution, Lessons Learned, Societal Benefits, and Moving Forward. Water Resources Research. 2021; 57 (2):1.
Chicago/Turabian StyleD. C. Goodrich; P. Heilman; M. Anderson; C. Baffaut; J. Bonta; D. Bosch; R. Bryant; M. Cosh; D. Endale; T. L. Veith; S. C. Havens; A. Hedrick; P. J. Kleinman; E. J. Langendoen; G. McCarty; T. Moorman; D. Marks; F. Pierson; J. R. Rigby; H. Schomberg; P. Starks; J. Steiner; T. Strickland; Teferi Tsegaye. 2021. "The USDA‐ARS Experimental Watershed Network: Evolution, Lessons Learned, Societal Benefits, and Moving Forward." Water Resources Research 57, no. 2: 1.
Soil erosion by gullies in Ethiopia is causing environmental and socioeconomic problems. A sound soil and water management plan requires accurately predicted gully erosion hotspot areas. Hence, this study develops a gully erosion susceptibility map (GESM) using frequency ratio (FR) and random forest (RF) algorithms. A total of 56 gullies were surveyed, and their extents were derived by digitizing Google Earth imagery. Literature review and a multicollinearity test resulted in 14 environmental variables for the final analysis. Model prediction potential was evaluated using the area under the curve (AUC) method. Results showed that the best prediction accuracy using the FR and RF models was obtained by using the top four most important gully predictor factors: drainage density, elevation, land use, and groundwater table. The notion that the groundwater table is one of the most important gully predictor factors in Ethiopia is a novel and significant quantifiable finding and is critical to the design of effective watershed management plans. Results from separate variable importance analyses showed land cover for Nitisols and drainage density for Vertisols as leading factors determining gully locations. Factors such as texture, stream power index, convergence index, slope length, and plan and profile curvatures were found to have little significance for gully formation in the studied catchment.
Selamawit Amare; Eddy Langendoen; Saskia Keesstra; Martine Ploeg; Habtamu Gelagay; Hanibal Lemma; Sjoerd Zee. Susceptibility to Gully Erosion: Applying Random Forest (RF) and Frequency Ratio (FR) Approaches to a Small Catchment in Ethiopia. Water 2021, 13, 216 .
AMA StyleSelamawit Amare, Eddy Langendoen, Saskia Keesstra, Martine Ploeg, Habtamu Gelagay, Hanibal Lemma, Sjoerd Zee. Susceptibility to Gully Erosion: Applying Random Forest (RF) and Frequency Ratio (FR) Approaches to a Small Catchment in Ethiopia. Water. 2021; 13 (2):216.
Chicago/Turabian StyleSelamawit Amare; Eddy Langendoen; Saskia Keesstra; Martine Ploeg; Habtamu Gelagay; Hanibal Lemma; Sjoerd Zee. 2021. "Susceptibility to Gully Erosion: Applying Random Forest (RF) and Frequency Ratio (FR) Approaches to a Small Catchment in Ethiopia." Water 13, no. 2: 216.
At a global scale, delta morphologies are subject to rapid change as a result of direct and indirect effects of human activity. This jeopardizes the ecosystem services of deltas, including protection against flood hazards, facilitation of navigation and biodiversity. Direct manifestations of delta morphological instability include river bank failure, which may lead to avulsion, persistent channel incision or aggregation, and a change of the sedimentary regime to hyperturbid conditions. Notwithstanding the in‐depth knowledge developed over the past decades about those topics, existing understanding is fragmented, and the predictive capacity of morphodynamic models is limited. The advancement of potential resilience analysis tools may proceed from improved models, continuous observations and the application of novel analysis techniques. Progress will benefit from synergy between approaches. Empirical and numerical models are built using field observations and, in turn, model simulations can inform observationists about where to measure. Information theory offers a systematic approach to test the realism of alternative model concepts. Once the key mechanism responsible for a morphodynamic instability phenomenon is understood, concepts from dynamic system theory can be employed to develop early warning indicators. In the development of reliable tools to design resilient deltas, one of the first challenges is to close the sediment balance at multiple scales, such that morphodynamic model predictions match with fully independent measurements. Such a high ambition level is rarely adopted, and is urgently needed to address the ongoing global changes causing sea‐level rise and reduced sediment input by reservoir building.
A. J. F. Hoitink; J. A. Nittrouer; P. Passalacqua; J. B. Shaw; E. J. Langendoen; Y. Huismans; D.S. van Maren. Resilience of River Deltas in the Anthropocene. Journal of Geophysical Research: Earth Surface 2020, 125, 1 .
AMA StyleA. J. F. Hoitink, J. A. Nittrouer, P. Passalacqua, J. B. Shaw, E. J. Langendoen, Y. Huismans, D.S. van Maren. Resilience of River Deltas in the Anthropocene. Journal of Geophysical Research: Earth Surface. 2020; 125 (3):1.
Chicago/Turabian StyleA. J. F. Hoitink; J. A. Nittrouer; P. Passalacqua; J. B. Shaw; E. J. Langendoen; Y. Huismans; D.S. van Maren. 2020. "Resilience of River Deltas in the Anthropocene." Journal of Geophysical Research: Earth Surface 125, no. 3: 1.
Computer simulation of reservoir sediment management strategies is becoming more important as worldwide water supply shrinks due to sediment deposition, while population growth continues. We identified the physical processes underlying each of the several alternatives available to transport incoming or deposited sediments downstream into receiving waters and the governing equations that describe each process. The purpose of this paper is to understand how physical characteristics of reservoir sediment management can be simulated with available computer codes. We described commonly available computer codes and their abilities to solve the appropriate equations in one, two, or three dimensions. The results revealed that one dimensional models are most appropriate for long-term simulations of the evolving reservoir bottom profile, while two or three dimensional codes are more appropriate for simulating density currents and detailed lateral movement of sediments, such as during local pressure flushing near reservoir outlets. We conclude that existing codes can successfully simulate sediment management, but because each code has limitations, they require seasoned judgment in their choice, application, and interpretation. Incorporating sediment prediction and management correctly into the planning, design, and operational phases of dam projects is essential for ensuring that the benefits of reservoir storage are sustained over the long term. The implications of our key findings are that sediment management strategies can be successfully simulated and that such simulations should be performed for our aging dams and newly proposed projects.
Razieh Anari; Rollin H. Hotchkiss; Eddy J. Langendoen. Elements for the Successful Computer Simulation of Sediment Management Strategies for Reservoirs. Water 2020, 12, 714 .
AMA StyleRazieh Anari, Rollin H. Hotchkiss, Eddy J. Langendoen. Elements for the Successful Computer Simulation of Sediment Management Strategies for Reservoirs. Water. 2020; 12 (3):714.
Chicago/Turabian StyleRazieh Anari; Rollin H. Hotchkiss; Eddy J. Langendoen. 2020. "Elements for the Successful Computer Simulation of Sediment Management Strategies for Reservoirs." Water 12, no. 3: 714.
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.
Assefa D. Zegeye; Eddy J. Langendoen; Tammo S. Steenhuis; Wolde Mekuria; Seifu A. Tilahun. Bank stability and toe erosion model as a decision tool for gully bank stabilization in sub humid Ethiopian highlands. Ecohydrology & Hydrobiology 2020, 20, 301 -311.
AMA StyleAssefa D. Zegeye, Eddy J. Langendoen, Tammo S. Steenhuis, Wolde Mekuria, Seifu A. Tilahun. Bank stability and toe erosion model as a decision tool for gully bank stabilization in sub humid Ethiopian highlands. Ecohydrology & Hydrobiology. 2020; 20 (2):301-311.
Chicago/Turabian StyleAssefa D. Zegeye; Eddy J. Langendoen; Tammo S. Steenhuis; Wolde Mekuria; Seifu A. Tilahun. 2020. "Bank stability and toe erosion model as a decision tool for gully bank stabilization in sub humid Ethiopian highlands." Ecohydrology & Hydrobiology 20, no. 2: 301-311.
Ephemeral streams with mobile beds represent a challenging environment for sediment transport prediction. Bed topography from relatively infrequent high flow events may persist after hydrograph recession, resulting in sediment transport over bed topography that is not in equilibrium with flow conditions. Previous research has shown that an equilibrium sand bed formed at a high flow rate followed by a near-instantaneous reduction in discharge and depth produced a gradual reduction in sediment load that could be modeled with a two-term exponential equation in which the first term described the reduction in bed-form celerity and the second term described the reworking of the bed to a new equilibrium condition. In this paper, flume experiments with a range of flow rates that produced dune bed forms were conducted to establish a more general predictive relationship for sediment load following rapid reductions in discharge and depth from equilibrium bed and flow conditions. It was found that the period of adjustment, as larger bed forms were reworked into smaller ones, depended on the final reduced rate of sediment transport. The rate constant for the term of the exponential function, which sets the gradual rate of sediment load reduction after the initial rapid drop, was shown to also describe the gradual reduction in bed-form amplitude that occurred after the discharge and depth were reduced. The results of this work may be used to estimate declining sediment transport rates in a sand-bedded channel resulting from rapid reduction of discharge and depth.
Daniel G. Wren; Roger A. Kuhnle; Eddy J. Langendoen. Sediment Transport and Bed-Form Characteristics for a Range of Step-Down Flows. Journal of Hydraulic Engineering 2020, 146, 04019060 .
AMA StyleDaniel G. Wren, Roger A. Kuhnle, Eddy J. Langendoen. Sediment Transport and Bed-Form Characteristics for a Range of Step-Down Flows. Journal of Hydraulic Engineering. 2020; 146 (2):04019060.
Chicago/Turabian StyleDaniel G. Wren; Roger A. Kuhnle; Eddy J. Langendoen. 2020. "Sediment Transport and Bed-Form Characteristics for a Range of Step-Down Flows." Journal of Hydraulic Engineering 146, no. 2: 04019060.
The structure of a mobile bed in a laboratory channel composed of sand and gravel (D50=8 mm) was characterized over a series of experiments with steady flows from a low flow, where only the finer fractions of the bed material were in motion to flows in which most bed material grain sizes were in motion. In each experiment, sediment transport rates were observed to initially be greater than the long-term mean rates, and fluctuations in transport rate decreased in period as bed shear stresses were increased. The bed surface median grain size increased with bed shear stress, while the sand fraction of the bed material organized into longitudinally extended corridors, which persisted as flow and transport rates were increased. The presence of the sand corridors was reflected by changes in the probability density function of the bed-surface elevation standard deviation evaluated at the grain-scale. The formation and organization of these corridors may have a strong influence on sand and gravel transport in channels with mixed sand and gravel bed material.
Roger A. Kuhnle; Daniel G. Wren; Eddy J. Langendoen. Structural Changes of Mobile Gravel Bed Surface for Increasing Flow Intensity. Journal of Hydraulic Engineering 2020, 146, 04019065 .
AMA StyleRoger A. Kuhnle, Daniel G. Wren, Eddy J. Langendoen. Structural Changes of Mobile Gravel Bed Surface for Increasing Flow Intensity. Journal of Hydraulic Engineering. 2020; 146 (2):04019065.
Chicago/Turabian StyleRoger A. Kuhnle; Daniel G. Wren; Eddy J. Langendoen. 2020. "Structural Changes of Mobile Gravel Bed Surface for Increasing Flow Intensity." Journal of Hydraulic Engineering 146, no. 2: 04019065.
One-dimensional (1D) models of open-channel flow are efficient for simulating in-channel hydrodynamics over long reaches and time periods, but cannot accurately simulate overbank flows that require two-dimensional (2D) models. The derivation and discussion of the behaviour of the coupling terms for horizontal and vertical coupling of the governing equations of 1D and 2D flow are presented here for the first time. Transfer terms for mass and momentum are introduced. Also, for the first time, the quantification of these transfer terms for the case of an experimental meandering channel with overbank flow is presented. For both coupling methods and relatively high overbank flow depth, the advective momentum transfer exceeded the diffusive momentum transfer. The diffusive momentum transfer has similar magnitude between both coupling approaches. The advective momentum transfer was one order of magnitude higher for the horizontal-coupling approach than for the vertical-coupling approach.
Cesar A. Simon; Eddy J. Langendoen; Jorge D. Abad; Alejandro Mendoza. On the governing equations for horizontal and vertical coupling of one- and two-dimensional open channel flow models. Journal of Hydraulic Research 2019, 58, 709 -724.
AMA StyleCesar A. Simon, Eddy J. Langendoen, Jorge D. Abad, Alejandro Mendoza. On the governing equations for horizontal and vertical coupling of one- and two-dimensional open channel flow models. Journal of Hydraulic Research. 2019; 58 (5):709-724.
Chicago/Turabian StyleCesar A. Simon; Eddy J. Langendoen; Jorge D. Abad; Alejandro Mendoza. 2019. "On the governing equations for horizontal and vertical coupling of one- and two-dimensional open channel flow models." Journal of Hydraulic Research 58, no. 5: 709-724.
Valley bottomland provides diverse agricultural and ecosystem benefits. Due to concentrated flow paths, they are more vulnerable to gully erosion than hillslope areas. The objective of this review was to show what caused valley bottoms gullies and to present deficiencies in existing rehabilitation measures. From the literature review, we found the following general trends: watershed characteristics determine location of valley bottom gullies; an increase in water transported from the watershed initiates the formation of gullies; the rate of change of the valley bottom gullies, once initiated, depends on the amount of rainfall and the soil and bedrock properties. Especially in humid climates, the presence of subsurface flow greatly enhances bank slippage and advancement of gully heads. Valley bottom gully reclamation measures are generally effective in arid and semi-arid areas with the limited subsurface flow and deep groundwater tables, whereas, for (sub) humid regions, similar remedial actions are not successful as they do not account for the effects of subsurface flows. To ensure effective implementation of rehabilitation measures, especially for humid regions, an integrated landscape approach that accounts for the combined subsurface and surface drainage is needed.
Selamawit Amare; Saskia Keesstra; Martine Van Der Ploeg; Eddy Langendoen; Tammo Steenhuis; Seifu Tilahun. Causes and Controlling Factors of Valley Bottom Gullies. Land 2019, 8, 141 .
AMA StyleSelamawit Amare, Saskia Keesstra, Martine Van Der Ploeg, Eddy Langendoen, Tammo Steenhuis, Seifu Tilahun. Causes and Controlling Factors of Valley Bottom Gullies. Land. 2019; 8 (9):141.
Chicago/Turabian StyleSelamawit Amare; Saskia Keesstra; Martine Van Der Ploeg; Eddy Langendoen; Tammo Steenhuis; Seifu Tilahun. 2019. "Causes and Controlling Factors of Valley Bottom Gullies." Land 8, no. 9: 141.
Urbanization can increase sheet, rill, gully, and channel erosion. We quantified the sediment budget of the Los Laureles Canyon watershed (LLCW), which is a mixed rural-urbanizing catchment in Northwestern Mexico, using the AnnAGNPS model and field measurements of channel geometry. The model was calibrated with five years of observed runoff and sediment loads and used to evaluate sediment reduction under a mitigation scenario involving paving roads in hotspots of erosion. Calibrated runoff and sediment load had a mean-percent-bias of 28.4 and − 8.1, and root-mean-square errors of 85% and 41% of the mean, respectively. Suspended sediment concentration (SSC) collected at different locations during one storm-event correlated with modeled SSC at those locations, which suggests that the model represented spatial variation in sediment production. Simulated gully erosion represents 16%–37% of hillslope sediment production, and 50% of the hillslope sediment load is produced by only 23% of the watershed area. The model identifies priority locations for sediment control measures, and can be used to identify tradeoffs between sediment control and runoff production. Paving roads in priority areas would reduce total sediment yield by 30%, but may increase peak discharge moderately (1.6%–21%) at the outlet.
Napoleon Gudino-Elizondo; Trent W. Biggs; Ronald L. Bingner; Eddy J. Langendoen; Thomas Kretzschmar; Encarnación V. Taguas; Kristine T. Taniguchi-Quan; Douglas Liden; Yongping Yuan. Modelling Runoff and Sediment Loads in a Developing Coastal Watershed of the US-Mexico Border. Water 2019, 11, 1024 .
AMA StyleNapoleon Gudino-Elizondo, Trent W. Biggs, Ronald L. Bingner, Eddy J. Langendoen, Thomas Kretzschmar, Encarnación V. Taguas, Kristine T. Taniguchi-Quan, Douglas Liden, Yongping Yuan. Modelling Runoff and Sediment Loads in a Developing Coastal Watershed of the US-Mexico Border. Water. 2019; 11 (5):1024.
Chicago/Turabian StyleNapoleon Gudino-Elizondo; Trent W. Biggs; Ronald L. Bingner; Eddy J. Langendoen; Thomas Kretzschmar; Encarnación V. Taguas; Kristine T. Taniguchi-Quan; Douglas Liden; Yongping Yuan. 2019. "Modelling Runoff and Sediment Loads in a Developing Coastal Watershed of the US-Mexico Border." Water 11, no. 5: 1024.
In river hydraulics, there is a continuing need for characterizing bed elevations to arrive at quantitative roughness measures that can be used in flow depth calculations and for improved prediction of fine-sediment transport over and through coarse beds. Recently published prediction methods require a method for estimating the cumulative distribution function (CDF) of bed elevations. Representing the distribution of elevations for rough beds requires a correct choice for the number and spacing of measurement locations. Laboratory experiments over a screeded flat gravel bed with sand having median diameter D50=35 mm were used to determine the number and spatial coverage of measurements needed to define the elevation field for a range of uncertainty levels. Approximately 1,000–5,000 randomly collected single elevation measurements were needed to quantify the distribution of elevations for the gravel bed. Relative error in estimating the standard deviation of elevations was insensitive to the number and spacing of elevation measurements when the spacing exceeded D50 (35 mm). The standard deviation of bed elevations was found to be proportional to the median bed material size for several different gravel beds. A method is presented for generating a CDF for bed elevations using the elevation-distribution standard deviation with a randomly sampled distribution function.
Daniel G. Wren; James R. Rigby; Eddy J. Langendoen; Roger A. Kuhnle. Sampling Interval Analysis and CDF Generation for Grain-Scale Gravel Bed Topography. Journal of Hydraulic Engineering 2018, 144, 04018065 .
AMA StyleDaniel G. Wren, James R. Rigby, Eddy J. Langendoen, Roger A. Kuhnle. Sampling Interval Analysis and CDF Generation for Grain-Scale Gravel Bed Topography. Journal of Hydraulic Engineering. 2018; 144 (10):04018065.
Chicago/Turabian StyleDaniel G. Wren; James R. Rigby; Eddy J. Langendoen; Roger A. Kuhnle. 2018. "Sampling Interval Analysis and CDF Generation for Grain-Scale Gravel Bed Topography." Journal of Hydraulic Engineering 144, no. 10: 04018065.
Arundo donax (giant reed) is a large, perennial grass that invades semi-arid riparian systems where it competes with native vegetation and modifies channel geomorphology. For the Santa Clara River, CA, changes in channel width and intensity of braiding over several decades are linked in part to high flow events that remove A. donax. Nevertheless, the area of A. donax at the two study sites increased fivefold over a period of 28 years at one site and fourfold over 15 years at the second site. Effects of A. donax on bank stability are compared to those of a common native riparian tree—Salix laevigata (red willow)—at two sites on the banks and floodplain of the Santa Clara River. There is a significant difference of root density of A. donax compared to S. laevigata and the latter has a higher number of roots per unit area at nearly all depths of the soil profile. Tensile root strength for S. laevigata (for roots of 1–6 mm in diameter) is about five times stronger than for A. donax and adds twice the apparent cohesion to weakly cohesive bank materials than does A. donax (8.6 kPa compared to 3.3 kPa, respectively). Modeling of bank stability for banks of variable height suggests that S. laevigata, as compared to A. donax, increases the factor of safety (FS) by ~60% for banks 1 m high, ~55% for banks 2 m high and ~40% for banks 3 m high. For 3 m high banks, the FS for banks with A. donax is
Jiana E. Stover; Edward A. Keller; Tom L. Dudley; Eddy J. Langendoen. Fluvial Geomorphology, Root Distribution, and Tensile Strength of the Invasive Giant Reed, Arundo Donax and Its Role on Stream Bank Stability in the Santa Clara River, Southern California. Geosciences 2018, 8, 304 .
AMA StyleJiana E. Stover, Edward A. Keller, Tom L. Dudley, Eddy J. Langendoen. Fluvial Geomorphology, Root Distribution, and Tensile Strength of the Invasive Giant Reed, Arundo Donax and Its Role on Stream Bank Stability in the Santa Clara River, Southern California. Geosciences. 2018; 8 (8):304.
Chicago/Turabian StyleJiana E. Stover; Edward A. Keller; Tom L. Dudley; Eddy J. Langendoen. 2018. "Fluvial Geomorphology, Root Distribution, and Tensile Strength of the Invasive Giant Reed, Arundo Donax and Its Role on Stream Bank Stability in the Santa Clara River, Southern California." Geosciences 8, no. 8: 304.
Soil erosion, with significant contributions from gullies, is a serious problem in the Ethiopian highlands. The objective of this paper is to examine patterns of discharge and sediment transport in the Ethiopian highlands, and to provide an initial assessment of whether soil and water conservation practices (SWCP) can reduce sediment loads in watersheds with actively eroding gullies. The study was conducted in the 414‐ha Ene‐Chilala watershed with a unimodal sub‐humid monsoon climate and actively eroding gullies in the valley bottoms. In 2013 and 2014, the local community was mandated to install upland infiltration furrows and farmers voluntarily rehabilitated six gully heads and protected 16 m of eroding stream banks. Discharge and sediment concentration were measured in two upslope watersheds and at the outlet. Since median infiltration capacity in the uplands was always greater than the rainfall intensity, saturation excess and interflow were main runoff pathways. After 175 mm cumulative rainfall, the groundwater table reached the surface in the valley bottoms, restricting infiltration, and runoff was generated as saturation excess overland flow and flowed through active gullies out of the watershed. Upland rill erosion on ploughed land early in the rain phase, and gully erosion in saturated valley bottoms thereafter, were sources of sediment in the rivers. The mandated infiltration furrows installed on the contour overtopped and damaged cropland. The off‐contour furrows increased streamflow. Gully rehabilitation of an upland gully effectively reduced stream sediment concentration in the upland weir. However, there was little benefit at the watershed outlet since the stream picked up the unconsolidated sediment from the failing banks in the downstream porting of the watershed. Therefore, soil conservation programs that in addition to installing upland practices, rehabilitate the main sediment source (gullies) appear to be the most effective approach to reducing in‐stream suspended sediment concentrations.
Getaneh K. Ayele; Meseret B. Addisie; Eddy J. Langendoen; Nigus H. Tegegne; Seifu A. Tilahun; Mamaru A. Moges; Charles F. Nicholson; Tammo S. Steenhuis. Evaluating erosion control practices in an actively gullying watershed in the highlands of Ethiopia. Earth Surface Processes and Landforms 2018, 43, 2835 -2843.
AMA StyleGetaneh K. Ayele, Meseret B. Addisie, Eddy J. Langendoen, Nigus H. Tegegne, Seifu A. Tilahun, Mamaru A. Moges, Charles F. Nicholson, Tammo S. Steenhuis. Evaluating erosion control practices in an actively gullying watershed in the highlands of Ethiopia. Earth Surface Processes and Landforms. 2018; 43 (13):2835-2843.
Chicago/Turabian StyleGetaneh K. Ayele; Meseret B. Addisie; Eddy J. Langendoen; Nigus H. Tegegne; Seifu A. Tilahun; Mamaru A. Moges; Charles F. Nicholson; Tammo S. Steenhuis. 2018. "Evaluating erosion control practices in an actively gullying watershed in the highlands of Ethiopia." Earth Surface Processes and Landforms 43, no. 13: 2835-2843.
The meandering Ribb River flows in northwest Ethiopia to Lake Tana, the source of the Blue Nile River. The river has already undergone changes due to several human interventions, such as embanking, sand mining, water extraction and lake level regulation for hydropower. At present, a dam and a weir are under construction to store and divert water for irrigation. This will strongly alter both water and sediment discharges to the downstream river reaches, causing adjustments to the morphology. Assessing the current morphodynamic trends is the first necessary step to study the future effects and find ways to mitigate them. This paper presents an analysis of the current and past river based on newly collected data, aerial photographs, SPOT and Google Earth images. The riverbed changes are derived from historical staff gauge height analysis. The effects of sediment mining and water extraction are assessed using the theory of morphodynamic equilibrium. The findings of the analysis show a reduction of sediment transport capacity in the downstream direction, which has resulted in intense sediment deposition, resulting in blockage of the Lower River reach and subsequent channel avulsion. The effects of Lake Tana level regulation on the observed processes appear to be minor.
Chalachew A. Mulatu; Alessandra Crosato; Michael M. Moges; Eddy J. Langendoen; Michael McClain. Morphodynamic Trends of the Ribb River, Ethiopia, Prior to Dam Construction. Geosciences 2018, 8, 255 .
AMA StyleChalachew A. Mulatu, Alessandra Crosato, Michael M. Moges, Eddy J. Langendoen, Michael McClain. Morphodynamic Trends of the Ribb River, Ethiopia, Prior to Dam Construction. Geosciences. 2018; 8 (7):255.
Chicago/Turabian StyleChalachew A. Mulatu; Alessandra Crosato; Michael M. Moges; Eddy J. Langendoen; Michael McClain. 2018. "Morphodynamic Trends of the Ribb River, Ethiopia, Prior to Dam Construction." Geosciences 8, no. 7: 255.
Both rural and urban development can lead to accelerated gully erosion. Quantify gully erosion is challenging in environments where gullies are rapidly repaired, and in urban areas where microtopographic complexity complicates the delineation of contributing areas. This study used Unmanned Aerial Systems (UASs) and Structure‐from‐Motion (SfM) photogrammetric techniques to quantify gully erosion in the Los Laureles Canyon watershed, a rapidly urbanizing watershed in Tijuana, Mexico. Following a storm event, the gully network extent was mapped using an orthomosaic (0.038 m pixel size); the local slope and watershed area contributing to each gully head were mapped with a Digital Surface Model (0.3 m pixel size). Gullies formed almost exclusively on unpaved roads which had erodible soils and concentrated flow. Management practices (e.g. road maintenance that fill gullies after large storms) contributed to total sediment production at the watershed scale. Sediment production from gully erosion was higher and threshold values of slope and drainage area for gully incision were lower than ephemeral gullies reported for agricultural settings. This indicate high vulnerability to gully erosion which is consistent with high soil erodibility and low critical shear stress measured in the laboratory with a mini jet‐erosion‐ test device. Future studies that evaluate effects of different soil types on gully erosion rates on unpaved roads, as well as model effects of management practices such as road paving and their impact on runoff, soil erosion, and sediment loads are crucial for proper sediment management and planning in urban watersheds.
Napoleon Gudino-Elizondo; Trent W. Biggs; Carlos Castillo; Ronald L. Bingner; Eddy J. Langendoen; Kristine T. Taniguchi; Thomas Kretzschmar; Yongping Yuan; Douglas Liden. Measuring ephemeral gully erosion rates and topographical thresholds in an urban watershed using unmanned aerial systems and structure from motion photogrammetric techniques. Land Degradation & Development 2018, 29, 1896 -1905.
AMA StyleNapoleon Gudino-Elizondo, Trent W. Biggs, Carlos Castillo, Ronald L. Bingner, Eddy J. Langendoen, Kristine T. Taniguchi, Thomas Kretzschmar, Yongping Yuan, Douglas Liden. Measuring ephemeral gully erosion rates and topographical thresholds in an urban watershed using unmanned aerial systems and structure from motion photogrammetric techniques. Land Degradation & Development. 2018; 29 (6):1896-1905.
Chicago/Turabian StyleNapoleon Gudino-Elizondo; Trent W. Biggs; Carlos Castillo; Ronald L. Bingner; Eddy J. Langendoen; Kristine T. Taniguchi; Thomas Kretzschmar; Yongping Yuan; Douglas Liden. 2018. "Measuring ephemeral gully erosion rates and topographical thresholds in an urban watershed using unmanned aerial systems and structure from motion photogrammetric techniques." Land Degradation & Development 29, no. 6: 1896-1905.
Modelling gully erosion in urban areas is challenging due to difficulties with equifinality and parameter identification, which complicates quantification 0of management impacts on runoff and sediment production. We calibrated a model (AnnAGNPS) of an ephemeral gully network that formed on unpaved roads following a storm event in an urban watershed (0.2 km2) in Tijuana, Mexico. Latin hypercube sampling was used to create 500 parameter ensembles. Modelled sediment load was most sensitive to the Soil Conservation Service (SCS) curve number, tillage depth (TD), and critical shear stress (τc). Twenty-one parameter ensembles gave acceptable error (behavioural models), though changes in parameters governing runoff generation (SCS curve number, Manning’s n) were compensated by changes in parameters describing soil properties (TD, τc), resulting in uncertainty in the optimal parameter values. The most suitable parameter combinations or “behavioural models” were used to evaluate uncertainty under management scenarios. Paving the roads increased runoff by 146–227%, increased peak discharge by 178–575%, and decreased sediment load by 90–94% depending on the ensemble. The method can be used in other watersheds to simulate runoff and gully erosion, to quantify the uncertainty of model-estimated impacts of management activities on runoff and erosion, and to suggest critical field measurements to reduce uncertainties in complex urban environments.
Napoleon Gudino-Elizondo; Trent W. Biggs; Ronald L. Bingner; Yongping Yuan; Eddy J. Langendoen; Kristine T. Taniguchi; Thomas Kretzschmar; Encarnacion V. Taguas; Douglas Liden. Modelling Ephemeral Gully Erosion from Unpaved Urban Roads: Equifinality and Implications for Scenario Analysis. Geosciences 2018, 8, 137 .
AMA StyleNapoleon Gudino-Elizondo, Trent W. Biggs, Ronald L. Bingner, Yongping Yuan, Eddy J. Langendoen, Kristine T. Taniguchi, Thomas Kretzschmar, Encarnacion V. Taguas, Douglas Liden. Modelling Ephemeral Gully Erosion from Unpaved Urban Roads: Equifinality and Implications for Scenario Analysis. Geosciences. 2018; 8 (4):137.
Chicago/Turabian StyleNapoleon Gudino-Elizondo; Trent W. Biggs; Ronald L. Bingner; Yongping Yuan; Eddy J. Langendoen; Kristine T. Taniguchi; Thomas Kretzschmar; Encarnacion V. Taguas; Douglas Liden. 2018. "Modelling Ephemeral Gully Erosion from Unpaved Urban Roads: Equifinality and Implications for Scenario Analysis." Geosciences 8, no. 4: 137.
Rehabilitation of large valley bottom gullies in developing countries is hampered by high cost. Stopping head cuts at the time of initiation will prevent large gullies from forming and is affordable. However, research on practices to control shallow gully heads with local materials is limited. The objective of this research was therefore to identify cost-effective shallow gully head stabilization practices. The four-year study was conducted on 14 shallow gullies (<3 m deep) in the central Ethiopian highlands. Six gullies were used as a control. Heads in the remaining eight gullies were regraded to a 1:1 slope. Additional practices implemented were adding either riprap or vegetation or both on the regraded heads and stabilizing the gully bed downstream. Gully heads were enclosed by fencing to prohibit cattle access to the planted vegetation. The median yearly head retreat of the control gullies was 3.6 m a−1 with a maximum of 23 m a−1. Vegetative treatments without riprap prevented gully incision by trapping sediments but did not stop the upslope retreat. The gully heads protected by riprap did not erode. Regrading the slope and adding riprap was most effective in controlling gully head retreat, and with hay grown on the fenced-in areas around the practice, it was profitable for farmers.
Meseret B. Addisie; Eddy J. Langendoen; Dessalew W. Aynalem; Getaneh K. Ayele; Seifu A. Tilahun; Petra Schmitter; Wolde Mekuria; Mikael M. Moges; Tammo S. Steenhuis. Assessment of Practices for Controlling Shallow Valley-Bottom Gullies in the Sub-Humid Ethiopian Highlands. Water 2018, 10, 389 .
AMA StyleMeseret B. Addisie, Eddy J. Langendoen, Dessalew W. Aynalem, Getaneh K. Ayele, Seifu A. Tilahun, Petra Schmitter, Wolde Mekuria, Mikael M. Moges, Tammo S. Steenhuis. Assessment of Practices for Controlling Shallow Valley-Bottom Gullies in the Sub-Humid Ethiopian Highlands. Water. 2018; 10 (4):389.
Chicago/Turabian StyleMeseret B. Addisie; Eddy J. Langendoen; Dessalew W. Aynalem; Getaneh K. Ayele; Seifu A. Tilahun; Petra Schmitter; Wolde Mekuria; Mikael M. Moges; Tammo S. Steenhuis. 2018. "Assessment of Practices for Controlling Shallow Valley-Bottom Gullies in the Sub-Humid Ethiopian Highlands." Water 10, no. 4: 389.