- Buffalo, New York, United States
Research Interests:
Research Interests:
Research Interests: Environmental Engineering, Civil Engineering, Geology, Water resources, Applied Economics, and 12 moreModel validation, Sediment transport, Root-Mean Square Error, Suspended Sediment, Riparian vegetation, Numerical Model, Finite Volume Method, Sediment Transport, Experimental Data, Large Woody Debris, Transport Equation, and Root mean square
Research Interests:
Research Interests:
<p>Soil erosion due to rainfall and overland flow can be detrimental to agricultural management and long-term agricultural sustainability. Although numerous conservation measures and planning strategies have greatly reduced... more
<p>Soil erosion due to rainfall and overland flow can be detrimental to agricultural management and long-term agricultural sustainability. Although numerous conservation measures and planning strategies have greatly reduced the amount of sediment moving within the landscape, there are still unresolved questions concerning initiation of particle motion, susceptibility to erosion, total soil loss, sediment transport and general measurement theory. Within agricultural fields, ephemeral erosion is particularly harmful because these sources can accelerate sediment transport, often yield more sediment than interrill sources and are more challenging to mitigate. In this study, terrain data were collected by aerial photogrammetry using an unmanned aerial system (UAS) following planting and approximately one month later, while climate variables during the period were collected using NexRad radar. Imagery was captured within seven agricultural fields (six in Iowa and one in Minnesota), ranging in size from 0.6 to 3.6 hectare (1.6 to 8.8 acre). Considering the small scale in topographic variation between two surveys, extreme efforts were applied to image processing and geospatial registration. Advanced models for camera calibration utilizing Micmac open-source photogrammetry software package were used to account for complex distortion patterns in the raw image data set. The undistorted images were then processed using Agisoft Photoscan for camera alignment, model georeferencing and dense point cloud generation (millions to billions of points per survey), from which digital elevation models (DEMs; 10 to 57 million cells) were produced. A physically-based finite element hydrodynamic and sediment transport model (CCHE2D, developed at the National Center for Computational Hydroscience and Engineering) was applied to simulate hydrological (runoff), sediment detachment (raindrop splash, sheet flow, and concentrated flow erosion) and sediment transport/deposition landscape evolution processes. Simulated geomorphological and sediment budget results over time were compared to field observations for model input parameter adjustment and consequently quantification of estimates. Integration of high-resolution spatial and temporal topographic measurements with physically-based numerical models support the development and validation of dynamic landscape evolution models needed for accurate prediction and quantification of gully initiation, evolution and impact on total soil loss and effective conservation management planning.</p>
Sedimentation issues were examined in a relatively large flood control reservoir in a highly unstable, cultivated watershed. Collected sediment cores were analyzed for 137 Cs and texture, which demarcated the as-built reservoir timeline,... more
Sedimentation issues were examined in a relatively large flood control reservoir in a highly unstable, cultivated watershed. Collected sediment cores were analyzed for 137 Cs and texture, which demarcated the as-built reservoir timeline, and the bulk chemistry of the sediments. The concentrations of select elements (As, Cu, Cr, Pb, Hg, and Zn) are positively correlated with clay composition and are not atypical for soils. Statistical analyses showed that since dam construction (1) select element concentrations normalized by clay and aluminum content do not vary vertically within each sediment core; and (2) depth-averaged concentrations of select element concentrations normalized by clay and aluminum content show no spatial variation within the sediment impoundment. These results suggest that sediment-associated chemical loadings to this reservoir have remained nearly invariant in time and evenly dispersed within the impoundment.
Research Interests:
River restoration and bank stabilization programs often use vegetation for improving stream corridor habitat, aesthetic, and function. Yet no study has examined the use of managed vegetation plantings to transform a straight, degraded... more
River restoration and bank stabilization programs often use vegetation for improving stream corridor habitat, aesthetic, and function. Yet no study has examined the use of managed vegetation plantings to transform a straight, degraded stream corridor into a more functional, aesthetically-pleasing meandering channel. Experimental data using a distorted Froude-scaled flume analysis shows that channel expansion and widening, thalweg meandering, and riffle and pool devlopement is possible using discrete plantings of rigid, emergent vegetation. These results were verified and validated using a recently developed numerical model. A hybrid method of meander design is proposed herein where managed vegetation plantings are used to trigger the desired morphologic response, transforming a straight, degraded reach into a more functional meandering corridor.
Ephemeral gullies serve as effective links transferring sediment and associated agrichemicals from upland areas to stream channels. Current erosion prediction technologies often require the exact topographic position (the length) of an... more
Ephemeral gullies serve as effective links transferring sediment and associated agrichemicals from upland areas to stream channels. Current erosion prediction technologies often require the exact topographic position (the length) of an ephemeral gully a priori, which greatly limits the utility of such models. The Revised Ephemeral Gully Erosion Model has been developed as a rational approach to predict ephemeral gully erosion and development. REGEM incorporates analytic formulations for plunge pool erosion and headcut retreat within single or multiple storm events in unsteady, spatially-varied flow at the sub-cell scale. The model employs sediment continuity equations for five soil particle-size classes to predict gully evolution and transport capacity. Event-based simulations demonstrate the model's utility for predicting the initial development of an ephemeral gully channel, while continuous simulations allow the channel to evolve over multiple runoff events accounting for sea...
Research Interests:
As headcut erosion accelerates, the formation of ephemeral gullies can significantly increase the loss of topsoil and decrease the productivity of agricultural lands. Ephemeral gullies are erosional features, usually larger than rills,... more
As headcut erosion accelerates, the formation of ephemeral gullies can significantly increase the loss of topsoil and decrease the productivity of agricultural lands. Ephemeral gullies are erosional features, usually larger than rills, caused by concentrated flow that may be erased by normal tillage practices. Most researchers agree that a critical or threshold level of concentrated flow is required to initiate ephemeral gullies and once initiated, there is positive feedback between flow and erosion. The location and size of ephemeral gullies is controlled by the generation of concentrated surface erosion of sufficient magnitude and duration to initiate and sustain erosion for a particular soil. Once formed, ephemeral gullies tend to rejuvenate near or in the same location from year to year. Experiments were conducted to examine the effect of a non-erodible layer on growth, development, and upstream migration of headcuts typical in ephemeral gullies. During migration, the depth of t...
Experiments were conducted using a soil-mantled flume subjected to simulated rain and downstream baselevel lowering to quantify the growth, development, and evolution of rills and rill networks. Digital elevation models constructed using... more
Experiments were conducted using a soil-mantled flume subjected to simulated rain and downstream baselevel lowering to quantify the growth, development, and evolution of rills and rill networks. Digital elevation models constructed using photogrammetric techniques greatly facilitated data acquisition and analysis. Results show that: (1) headcuts formed by baselevel lowering were the primary drivers of rill incision and network development, and the communication of this wave of degradation occurred very quickly and efficiently through the landscape, (2) rill networks extended upstream by headcut erosion, where channels bifurcated and filled the available space, (3) rill incision, channel development, and peaks in sediment efflux occurred episodically, linked directly to the downstream baselevel adjustments, and (4) sediment discharge and rill drainage density approached nearly constant or asymptotic values with time following baselevel adjustments despite the continuous application o...
ABSTRACT A new metaheuristic approach is presented to discover transition rules for a cellular automaton (CA) model using a novel bat movement algorithm (BA). CA is capable of simulating the evolution of complex geographical phenomena,... more
ABSTRACT A new metaheuristic approach is presented to discover transition rules for a cellular automaton (CA) model using a novel bat movement algorithm (BA). CA is capable of simulating the evolution of complex geographical phenomena, and transition rules lie at the core of these models. An intelligence algorithm based on the echolocation behavior of bats is used to discover explicit transition rules for use in simulating urban expansion. CA transition rules are formed by links between attribute constraint items and classification items. The transition rules are derived using the BA to optimize the lower and upper threshold values for each attribute. The BA-CA model is then constructed for the simulation of urban expansion observed for Nanjing City, China. The total accuracy of newly formulated BA-CA model for this application is 86.9%, and the kappa coefficient is 0.736, which strongly suggest that the interactions of bats are effective in capturing the relationships between spatial variables and urban dynamics. It is further demonstrated that this bat-inspired BA-CA model performs better than the null model, the particle swarm optimization-based CA model (PSO-CA), and the ant colony optimization-based CA model (ACO-CA) using the same dataset. The model validation and comparison illustrate the novel capability of BA for discovering transition rules of CA during the simulation of urban expansion and potentially for other geographic phenomena.
Research Interests:
Research Interests:
Research Interests:
In this study, we applied a stepped-combustion approach to dating post-bomb lake sediment from north-central Mississippi. Samples were combusted at a low temperature (400 °) and then at 900 °. The CO2was collected separately for both... more
In this study, we applied a stepped-combustion approach to dating post-bomb lake sediment from north-central Mississippi. Samples were combusted at a low temperature (400 °) and then at 900 °. The CO2was collected separately for both combustions and analyzed. The goal of this work was to develop a methodology to improve the accuracy of14C dating of sediment by combusting at a lower temperature and reducing the amount of reworked carbon bound to clay minerals in the sample material. The14C fraction modern results for the low and high temperature fractions of these sediments were compared with well-defined137Cs determinations made on sediment taken from the same cores. Comparison of “bomb curves” for14C and137Cs indicate that low temperature combustion of sediment improved the accuracy of14C dating of the sediment. However, fraction modern results for the low temperature fractions were depressed compared to atmospheric values for the same time frame, possibly the result of carbon mixi...
Research Interests:
ABSTRACT Due to fragmentized terrain and physiognomy of typical loess landform, long-term anthropogenic influences, and inherent vulnerability, soil erosion is a serious problem in the Loess Plateau of China. There is a critical need to... more
ABSTRACT Due to fragmentized terrain and physiognomy of typical loess landform, long-term anthropogenic influences, and inherent vulnerability, soil erosion is a serious problem in the Loess Plateau of China. There is a critical need to assess soil erosion and spatial distribution for achieving sustainable land use and comprehensive soil conservation management. Taking the Yangou watershed as a case and using the Landsat Thematic Mapper image (land use map), Digital Elevation Model (DEM), soil maps, and precipitation data, this study integrated the revised universal soil loss equation (RUSLE) with GIS technology to estimate soil loss and its spatial distribution. The benefits of soil conservation of land use types were analyzed and the measures for future soil conservation planning were discussed. The results show that silt-covered land and terrace have high benefits of soil conservation, indicating that building check dam, producing silt-covered land for farming, and converting sloped farmland to terrace are effective ways to control soil erosion in the Yangou watershed. Furthermore, increasing vegetation coverage on lower coverage grassland, especially on the slopes with gradients >25°, and eliminating human disturbance in barren areas are feasible and effective measures for soil conservation planning. This study reveals that the integrated RUSLE-GIS model can evaluate and map soil erosion quantitatively and spatially at watershed scale in the Loess Plateau of China. The findings suggest strategies for coping with future soil conservation planning and provide valuable references for future assessments both in the Loess Plateau of China and elsewhere.
Research Interests:
Page 37. Effects of Emergent Riparian Vegetation on Spatially Averaged and Turbulent Flow Within an Experimental Channel Sean J. Bennett US Department of Agriculture-Agricultural Research Service, National Sedimentation ...
Research Interests:
Research Interests:
The establishment of Total Maximum Daily Loads (TMDL) for contaminants entering water bodies requires the development of suitable methods for contaminant measurement. In an effort to assess quantities of suspended-sediment transport, an... more
The establishment of Total Maximum Daily Loads (TMDL) for contaminants entering water bodies requires the development of suitable methods for contaminant measurement. In an effort to assess quantities of suspended-sediment transport, an acoustic device is being developed in a ...
Research Interests:
Research Interests: Geology and Geomorphology
Research Interests:
Since 1948, the USDA-NRCS has constructed nearly 11,000 flood control dams across the United States, and many of the reservoirs are rapidly filling with sediment. To rehabilitate these structures, the impounded sediment must be assessed... more
Since 1948, the USDA-NRCS has constructed nearly 11,000 flood control dams across the United States, and many of the reservoirs are rapidly filling with sediment. To rehabilitate these structures, the impounded sediment must be assessed to determine the volume of accumulated sediment and the potential hazard this sediment may pose if reintroduced to the environment. An assessment of sedimentation issues
Research Interests:
Research Interests:
Research Interests:
Research Interests:
River restoration that can be accomplished by structural and nonstructural means is one of the most important and popular recent advances in river engineering. Stream restoration techniques generally focus on protecting or restoring... more
River restoration that can be accomplished by structural and nonstructural means is one of the most important and popular recent advances in river engineering. Stream restoration techniques generally focus on protecting or restoring aquatic, riparian, and floodplain ...
Research Interests:
WR_description.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
WR_description.
Research Interests:
Research Interests:
WR_description.
Research Interests:
Research Interests:
Research Interests:
Skip to Main Content. ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Visual-based rapid assessment techniques provide an efficient method for characterizing the restoration potential of streams, with many focusing on channel stability and instream habitat features. Few studies, however, have compared these... more
Visual-based rapid assessment techniques provide an efficient method for characterizing the restoration potential of streams, with many focusing on channel stability and instream habitat features. Few studies, however, have compared these techniques to see if they result in differing restoration priorities. Three rapid assessment techniques were contrasted at three wild trout streams in western New York with different amounts of channel disturbance. Two methods focused only on geomorphic stability, whereas the third addressed physical habitat condition. Habitat assessment scores were not correlated with scores for either geomorphic assessment method and they varied more between channels with different degrees of disturbance. A model based on dynamic equilibrium concepts best explains the variation among the streams and techniques because it accounts for a stream's capacity to maintain ecological integrity despite some inherent instability. Geomorphic indices can serve as effective proxies for biological indices in highly disturbed systems. Yet, this may not be the case in less disturbed systems, where geomorphic indices cannot differentiate channel adjustments that impact biota from those that do not. Dynamically stable streams can include both stable and unstable reaches locally as characterized by geomorphic methods and translating these results into restoration priorities may not be appropriate if interpretations are limited to the reach scale.
Research Interests:
... the test section. ~ : l-In(S/ (2a) \Yo/ ~-~ = U.2p (2b) where U. is shear velocity, K is the yon furman coefficient, yis the distance from the bed corresponding to velocity U, andYo is the zero-velocity roughness height. Because all... more
... the test section. ~ : l-In(S/ (2a) \Yo/ ~-~ = U.2p (2b) where U. is shear velocity, K is the yon furman coefficient, yis the distance from the bed corresponding to velocity U, andYo is the zero-velocity roughness height. Because all flows ...
Research Interests: Geology and Sedimentary
Page 1. Journal of Hydraulic Research Vol. 44, No. 4 (2006), pp. 510521 © 2006 International Association of Hydraulic Engineering and Research Turbulent flow and bed pressure within headcut scour holes due to plane reattached jets ...
Research Interests:
ABSTRACT
Research Interests:
Surface Wave Forces Acting on Submerged Logs. [Journal of Hydraulic Engineering 128, 349 (2002)]. Nicholas P. Wallerstein, Carlos V. Alonso, Sean J. Bennett, Colin R. Thorne. Abstract. Drag forces exerted on cylindrical simulated ...