Download or read book Quantifying Erosion and Deposition Due to Stream Planform Change Using High Spatial Resolution Digital Orthophotography and Lidar Data written by Kerrie M. Garvey and published by . This book was released on 2012 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: High sediment loads in rivers and streams are one of the most widespread and important causes of impairment nationally and worldwide. Negative impacts include decreased water quality, channel stability, and habitat health, as well as the economic costs to address these issues. Locally, state and provincial governments have attempted to limit non-point sources of sediment and closely linked phosphorus loading to Lake Champlain and other waters in recent decades. Quantitative estimates of the relative importance of sediment sources, and in particular agriculture vs. streambank erosion, is needed at watershed spatial scales to support these efforts.
Download or read book Flooding and Equilibrium of Stream Channels written by Keith McBride Kantack and published by . This book was released on 2016 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: While floods have been widely studied, quantifying or predicting their impacts remains challenging for geomorphologists. Often the spatial or temporal scales of analysis prevent robust analytics: spatially, studies typically have been done on the cross section scale or temporally by comparing pre- to post-flood geospatial datasets. In this study, to capture the response and recovery process following a catastrophic flood generated by Tropical Storm Irene, we use high-resolution ({u2264}lm) lidar data from before the flood (2010), one year after the flood (2012), and four years after the flood (2015) to build a predictive model of erosion and deposition, as well as assess the changes in the variability of the channel's unit stream power curve, which we use as a proxy for reach-scale equilibrium. Findings suggest that the downstream gradient in unit stream power is a powerful predictor of erosion and deposition, but where the two-year flow exceeds 150 W/m2, erosion is the dominant response. The result of this is the reduction of variation in the unit stream power curve over the ~l km scale, which we argue to be a change in the direction of reach-scale equilibrium.
Download or read book Quantifying Gully Erosion in West Tennessee Using High Resolution LIDAR Data written by John James McNelis and published by . This book was released on 2016 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research demonstrates the use of Light Detection and Ranging (LIDAR) for detailed measurement of volume change and erosional and depositional processes within a small gully and assessing the impact of digital elevation model (DEM) resolution on these measurements. The study site is an active gully in Meeman-Shelby Forest State Park in Tennessee, USA. DEMs were derived from an airborne LIDAR survey and multiple terrestrial LIDAR scans. DEM differences were used to quantify gross volumes of erosion and deposition within the gully over a three year period and a 49 day period. Analysis of the airborne LIDAR point cloud indicated that approximately 10,000 m3 of material eroded from the bluff since the gully was formed between 1969 and 1973. A total volume of 615.8 m3 of material was discharged from the gully between January 2012 (the airborne LIDAR survey) and December 2014 (the first terrestrial LIDAR survey). The surveys using the terrestrial laser scanner generated two 2 cm DEMs representing the gully terrain change during a short period of 49 days between December 2014 and February 2015. The comparison of these two DEMs indicates an estimated 2.1 m3 of material was imported into the gully bottom with 11.5 m3 of gross erosion and 13.6 m3 of gross deposition. The same analysis performed at reduced data resolutions helped identify a turning point in the trends of erosion and deposition estimates at 0.18 m and 0.24 m resolutions, respectively, indicating that higher data densities of the LIDAR point data did not substantially improve the results. The two turning points represent the critical resolutions at which the accuracy of erosion and deposition measurements begin to deteriorate. This study demonstrates that high accuracy and density of point cloud data collected using LIDAR are capable to detect and quantify short term changes in dynamic gully systems. This study also suggests an optimum point density between 10 and 30 points per square meter to maximize efficiency of data collection and processing. The analyses described in this thesis serve as a starting point for further monitoring development of the pool gully at very fine scales.
Download or read book Geomorphological Relationships Through the Use of 2 D Seismic Reflection Data Lidar and Aerial Imagery written by Meghan Elizabeth Alesce and published by . This book was released on 2014 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barrier Islands are crucial in protecting coastal environments. This study focuses on Dauphin Island, Alabama, located within the Northern Gulf of Mexico (NGOM) Barrier Island complex. It is one of many islands serving as natural protection for NGOM ecosystems and coastal cities. The NGOM barrier islands formed at 4 kya in response to a decrease in rate of sea level rise. The morphology of these islands changes with hurricanes, anthropogenic activity, and tidal and wave action. This study focuses on ancient incised valleys and and the impact on island morphology on hurricane breaches. Using high frequency 2-D seismic reflection data four horizons, including the present seafloor, were interpreted. Subaerial portions of Dauphin Island were imaged using Lidar data and aerial imagery over a ten-year time span, as well as historical maps. Historical shorelines of Dauphin Island were extracted from aerial imagery and historical maps, and were compared to the location of incised valleys seen within the 2-D seismic reflection data. Erosion and deposition volumes of Dauphin Island from 1998 to 2010 (the time span covering hurricanes Ivan and Katrina) in the vicinity of Katrina Cut and Pelican Island were quantified using Lidar data. For the time period prior to Hurricane Ivan an erosional volume of 46,382,552 m3 and depositional volume of 16,113.6 m3 were quantified from Lidar data. The effects of Hurricane Ivan produced a total erosion volume of 4,076,041.5 m3. The erosional and depositional volumes of Katrina Cut being were 7,562,068.5 m3 and 510,936.7 m3, respectively. More volume change was found within Pelican Pass. For the period between hurricanes Ivan and Katrina the erosion volume was 595,713.8 m3. This was mostly located within Katrina Cut. Total deposition for the same period, including in Pelican Pass, was 15,353,961 m3. Hurricane breaches were compared to ancient incised valleys seen within the 2-D seismic reflection results. Breaches from hurricanes from 1849, 1916, and 2005 all correlated with incised valley. Interpretations from horizons A and P correlated well with the 1849 shoreline, while Horizon B correlated best with the 1916 and 2005 hurricane breaches. The correlation of incised valleys and breaches provides a probable causation of breach locations. With further investigations, determination of the impacts of these relict valleys can be validated and established. Preferential subsidence within the relict incised valleys would account for the lower elevations on the island surface. Very fine to fine grained sediment deposits from the Mobile Bay would contribute to preferential subsidence. The lower elevations are more likely to erode from overwash and surges during strong storm systems.
Download or read book Debris flow Erosion and Deposition Dynamics written by Peter Schürch and published by . This book was released on 2011 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Debris flows are a major natural hazard in mountains world wide, because of their destructive potential. Prediction of occurrence, magnitude and travel distance is still a scientific challenge, and thus research into the mechanics of debris flows is still needed. Poor understanding of the processes of erosion and deposition are partly responsible for the difficulties in predicting debrisflow magnitude and travel distance. Even less is known about the long-term evolution of debrisflow fans because the sequential effects of debris-flow erosion and deposition in thousands of flows are poorly documented and hence models to simulate debris-flow fans do not exist. Here I address the specific issues of the dynamics of erosion and deposition in single flows and over multiple flows on debris-flow fans by terrain analysis, channel monitoring and fan evolution modeling. I documented erosion and deposition dynamics of debris flows at fan scale using the Illgraben debris-flow fan, Switzerland, as an example. Debris flow activity over the past three millenia in the Illgraben catchment in south-western Switzerland was documented by geomorphic mapping, radiocarbon dating of wood and cosmogenic exposure dating of deposits. In this specific case I also documented the disturbance induced by two rock avalanches in the catchment resulting in distinct patterns of deposition on the fan surface. Implications of human intervention and the significance of autogenic forcing of the fan system are also discussed. Quantification and understanding of erosion and deposition dynamics in debris flows at channel scale hinges on the ability to detect surface change. But change detection is a fundamental task in geomorphology in general. Terrestrial laser scanners are increasingly used for monitoring down to centimeter scale of surface change resulting from a variety of geomorphic processes, as they allow the rapid generation of high resolution digital elevation models. In this thesis procedures were developed to measure surface change in complex topography such as a debris-flow channel. From this data high-resolution digital elevation models were generated. But data from laser scanning contains ambiguous elevation information originating from point cloud matching, surface roughness and erroneous measurments. This affects the ability to detect change, and results in spatially variable uncertainties. I hence developed techniques to visualize and quantify these uncertainties for the specific application of change detection. I demonstrated that use of data filters (e.g. minimum height filter) on laser scanner data introduces systematic bias in change detection. Measurement of debris-flow erosion and deposition in single events was performed at Illgraben, where multiple debris flows are recorded every year. I applied terrestrial laser scanning and flow hydrograph analysis to quantify erosion and deposition in a series of debris flows. Flow depth was identified as an important control on the pattern and magnitude of erosion, whereas deposition is governed more by the geometry of flow margins. The relationship between flow depth and erosion is visible both at the reach scale and at the scale of the entire fan. Maximum flow depth is a function of debris flow front discharge and pre-flow channel cross section geometry, and this dual control gives rise to complex interactions with implications for long-term channel stability, the use of fan stratigraphy for reconstruction of past debris flow regimes, and the predictability of debris flow hazards. Debris-flow fan evolution on time scales of decades up to ten thousands of years is poorly understood because the cumulative effects of erosion and deposition in subsequent events are rarely well documented and suitable numerical models are lacking. Enhancing this understanding is crucial to assess the role of autogenic (internal) and allogenic (external) forcing mechanisms on building debris-flow fans over long time scales. On short time scales understanding fan evolution is important for debris-flow hazard assessment. I propose a 2D reduced-complexity model to assess debris-flow fan evolution. The model is built on a broad range of qualitative and empirical observations on debris-flow behaviour as well as on monitoring data acquired at Illgraben as part of this thesis. I have formulated a framework of rules that govern debris-flow behaviour, and that allows efficient implementation in a numerical simulation. The model is shown to replicate the general behaviour of alluvial fans in nature and in flume experiments. In three applications it is demonstrated how fan evolution modeling may improve understanding of inundation patterns, surface age distribution and surface morphology.
Download or read book Sediment Dynamics and Channel Connectivity on Hillslopes written by Xiaoyu Lu and published by . This book was released on 2018 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pattern, magnitude, and frequency of hillslope erosion and deposition are spatially varied under the influence of micro-topography and channel geometry. This research investigates the interrelationships between erosion/deposition, micro-topography, and channel connectivity on a hillslope in Loudon, Tennessee using the centimeter (cm) level temporal Digital Elevation Models collected using laser scanning. This research addressed (1) the effect of spatial resolution on the erosion/deposition quantification, and rill delineation; (2) the influences of micro-topographic factors (e.g. slope, roughness, aspect) on erosion and deposition; (3) the relationship between the structural connectivity -- depressions and confluence of rills -- and the sedimentological connectivity. I conducted (1) visual and quantitative assessments for the erosion and deposition, and the revised automated proximity and conformity analysis for the rill network; (2) quantile regression for micro-topographic factors using segmented rill basins; and (3) cross-correlation analysis using erosion and deposition series along the channels. Overall, rills are sedimentologically more dynamic than the interrill areas. A larger grid size reduces the detectable changes in both areal and volumetric quantities, and also decreases the total length and number of rills. The offset between delineated rills and the reference increases with larger grid sizes. A larger rill basin has higher erosion and deposition with the magnitude of erosion greater than deposition. The slope has a positive influence on erosion and a negative one on deposition; roughness has a positive influence on deposition and a negative one on erosion. Areas that are more north-facing experience higher erosion and lower deposition. Rill length explains 46% of the variability for erosion and 24% for deposition. The depressions are associated with higher erosion in the downslope direction. The correlations between the erosion and the confluence are positive; the correlation between the deposition and the sink is positive. Overall, the influence of structural connectivity on the sedimentological connectivity is within 25 cm in both upstream and downstream directions. This research contributes to the understanding in how the sediment movement on hillslopes is governed by topographic variations and channel connectivity, and future work may explore hillslope channels at broader geographical and temporal scales.
Download or read book Quantifying Impervious Surface Area with Moderate Resolution Hyperspectral Imagery and Lidar Data written by Shawn Richard Callihan and published by . This book was released on 2006 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Partitioned by Process written by Nicholas Ellett and published by . This book was released on 2019 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In mountainous regions burned by wildfires, profound changes in soil characteristics and combustion of vegetation increase hillslope and channel erosion during storm events. Reduced infiltration and abundant loose sediment produce large post-fire erosional events which endanger human lives and infrastructure and contribute significantly to long-term erosion rates. While the influence of fire in increasing erosion has long been recognized, quantifying volumes and sources of eroded material from burned landscapes is difficult. Pre-erosion high-resolution topographic data (e.g. lidar) are often not available in burned areas and determining specific contributions from post-fire hillslope and channel erosion is challenging. Multiple erosional processes mobilize sediment from hillslopes, but the connectivity of hillslopes to channels controls the basin-wide erosional response. We quantify an important spatial threshold separating hillslope and channel erosion processes in a catchment burned in the 2016 Pioneer Fire. Further, we confirm the impact of post-fire erosion on landscape evolution, demonstrate the applicability of Structure from Motion photogrammetry (SfM) to quantify post-fire erosion without detailed pre-erosion topography, and improve estimates of rill erosion at adequate spatial scales. In this rugged 0.95 km2 watershed in the weathered Idaho Batholith, widespread rilling and channel erosion produced a runoff-generated debris flow following modest precipitation in October 2016. We implemented unmanned aerial vehicle (UAV)-based SfM to derive 5 cm resolution topography of the channel scoured by debris flow. Lacking cm-resolution pre-erosion topography, we created a synthetic surface defined by the debris flow scour's geomorphic signature and used a DEM of difference (DoD) to map and quantify channel erosion, finding 3467 ± 422 m3 was eroded by debris flow scour. Rill dimensions along hillslope transects and Monte Carlo simulation show rilling eroded ~1100 m3 of sediment and define a volume uncertainty of 29%. Next, we delineated sub-basins within the larger study catchment to investigate the evolution of hillslope and channel erosion with varying contributing areas. We document that a drainage area of 20 ha (0.2 km2) represents the threshold from dominantly hillslope to dominantly channel erosion in this setting. Hillslopes contribute less to total erosion as drainage area increases, reflecting increased connectivity and efficiency of channel networks. Our experimental sub-basin results show a positive relationship between sediment yield (mass/area/time) and drainage area; contrary to most literature. The modern deposit volume was 5700 ± 1140 m3, indicating ~60% contribution from post-fire channel erosion. Our measured total eroded volume (4600 ± 740 m3) aligns closely with the preliminary assessment from the US Geological Survey (USGS) post-fire hazard model for similar, modest precipitation intensities."--Boise State University ScholarWorks.
Download or read book High resolution Lidar Mapping and Analysis to Quantify Surface Movement of Swift Creek Landslide Whatcom County WA written by Benjamin R. Ferreira and published by . This book was released on 2014 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On Landsurface Change Detection Using Lidar Datasets of Different Spatial Resolutions written by Michael James Madsen and published by . This book was released on 2017 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light detection and ranging (LiDAR) data were collected over the Colorado Springs, Colorado Waldo Canyon fire burn scar the year before and the year after the 2012 Waldo Canyon fire. The post-fire LiDAR data were collected after a multi-day major flood event that occurred September of 2013. The 2011 and 2013 datasets were collected at different spatial resolutions. This research tests whether, and to what degree, these two datasets can be compared to detect topographic change resulting from the 2013 and other flood events that mobilized and redeposited sediment across the burn scar. This thesis establishes a best-practice geographic information system (GIS) workflow that is designed to detect geomorphic change, despite limitations imposed when comparing datasets of different spatial resolutions. Results indicate that an error associated with the 2011 dataset created an offset that blurred all landscape scale changes following the Waldo Canyon fire. Organizations seeking to perform change detection from LiDAR datasets of varying spatial resolution could benefit by following the methods presented here.
Download or read book A Geoinformatics Approach to Water Erosion written by Tal Svoray and published by Springer. This book was released on 2022-02-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Degradation of agricultural catchments due to water erosion is a major environmental threat at the global scale, with long-lasting destructive consequences valued at tens of billions of dollars per annum. Eroded soils lead to reduced crop yields and deprived agroecosystem’s functioning through, for example, decreased water holding capacity, poor aeration, scarce microbial activity, and loose soil structure. This can result in reduced carbon sequestration, limited nutrient cycling, contamination of water bodies due to eutrophication, low protection from floods and poor attention restoration—consequences that go far beyond the commonly modelled soil loss and deposition budgets. This book demonstrates, using data from the Harod catchment in northern Israel, how cutting-edge geoinformatics, data science methodologies and soil health indicators can be used to measure, predict, and regulate these major environmental hazards. It shows how these approaches are used to quantify—in time and space—the effect of water erosion not only on the soil layer, soil minerals, and soil loss, but also on the wide-range of services that agricultural ecosystems might supply for the benefit and well-being of humans. The algorithms described in this book play a major role in this paradigm shift and they include, for example, extraction of photogrammetric DEMs from drone's data, advanced drainage structure calculations, fuzzy process-based modelling and spatial topographic threshold computations, multicriteria analyses and expert-based systems development using analytic hierarchal processes, innovative data-mining and machine learning tools, autocorrelation and interpolation of soil health, physically-based soil evolution models, spatial decision support systems and many more.
Download or read book Monitoring of Soil Erosion Processes Using High Spatial Resolution Remote Sensing Data written by S. Oppitz and published by . This book was released on 1997 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Active Faulting Controls on the Geometry of Alluvial Landforms Quantified Using High Resolution Topography written by Alexander Edward Morelan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alluvial landforms deposited adjacent to active faults may reflect fault slip in their morphology. Traditional neotectonic methods measure displacement along active faults using the linear and planar markers produced by incision into alluvial fans. In this thesis I explore how the landform-scale morphology of alluvial fans, reflecting the balance between tectonic subsidence and sediment deposition in basins, may be quantitatively related to fault slip. I develop novel techniques using high resolution topography to quantify both fault slip and slip rates. In chapter one I use high resolution topographic data to evaluate the activity of the Mill Creek and Mission Creek strands of the San Andreas fault in the San Bernardino Mountains north of San Gorgonio Pass. Airborne lidar data is used to conduct a reconnaissance survey along the length of the two fault strands and to identify a site on each fault to quantify its activity. One site, on the Mill Creek fault, is shown to not record fault slip in latest Pleistocene surficial deposits. Slip along the Mission Creek fault offsets both an alluvial fan deposit and adjacent canyon walls. I develop a kinematic model to estimate the amount of oblique fault slip required to produce the observed displacements, and use the cosmogenic isotope Beryllium-10 (10Be) to constrain the age of the displaced alluvial fan surface and measure a slip rate for the Mission Creek fault at this site. Chapter two contains the development and test of a conceptual model of the interplay between oblique strike-slip fault movement and the deposition of alluvial fans. This chapter represents the failure to reject a null hypothesis and motivates the two subsequent chapters that focus on dynamics and timescales of alluvial fan deposition. In chapter three, I develop a method to estimate the deposition rate and resurfacing timescale of alluvial fans in active, extensional tectonic environments. Using lidar point-cloud data to quantify landform-scale roughness, I find that alluvial fans with larger average maximum grain sizes tend to be rougher on the landform scale, suggesting a link between grain size distribution and the geometry of debris-flow deposits. By relating volumetric sediment flux, quantified from the concentration of 10Be in sediment, to fan area and roughness, I estimate the timescale for resurfacing alluvial fans. I find that faulted range fronts with higher vertical fault slip rates tend to host fans with more rapid vertical deposition rates, which supports models of tectonic extension where more than half of fault displacement at the range front is accommodated by basin subsidence. In chapter four, I use high-resolution topographic data to relate the steepness of alluvial fans to the rate of slip of basin-bounding normal faults. I confirm previous empirical studies that associate rapid tectonic subsidence with smaller map-view alluvial fans. I further show that the slope of alluvial fans, after normalizing for source-catchment area, is even more sensitive to the fault slip rate. Controlling for climate and lithology, fan slopes may be used to quantify fault slip rates at tectonically controlled mountain-range fronts.
Download or read book Structure from Motion in the Geosciences written by Jonathan L. Carrivick and published by John Wiley & Sons. This book was released on 2016-07-15 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structure from Motion with Multi View Stereo provides hyperscale landform models using images acquired from standard compact cameras and a network of ground control points. The technique is not limited in temporal frequency and can provide point cloud data comparable in density and accuracy to those generated by terrestrial and airborne laser scanning at a fraction of the cost. It therefore offers exciting opportunities to characterise surface topography in unprecedented detail and, with multi-temporal data, to detect elevation, position and volumetric changes that are symptomatic of earth surface processes. This book firstly places Structure from Motion in the context of other digital surveying methods and details the Structure from Motion workflow including available software packages and assessments of uncertainty and accuracy. It then critically reviews current usage of Structure from Motion in the geosciences, provides a synthesis of recent validation studies and looks to the future by highlighting opportunities arising from developments in allied disciplines. This book will appeal to academics, students and industry professionals because it balances technical knowledge of the Structure from Motion workflow with practical guidelines for image acquisition, image processing and data quality assessment and includes case studies that have been contributed by experts from around the world.
Download or read book Monitoring of Soil Erosion Processes Using High Spatial Resolution Remote Sensing Data written by S. Oppitz and published by . This book was released on 1997 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gravel Bed Rivers written by Michael Church and published by John Wiley & Sons. This book was released on 2012-02-10 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravel-Bed Rivers: Processes, Tools, Environments presents a definitive review of current knowledge of gravel-bed rivers, derived from the 7th International Gravel-bed Rivers Workshop, the 5-yearly meeting of the world’s leading authorities in the field. Each chapter in the book has been specifically commissioned to represent areas in which recent progress has been made in the field. The topics covered also represent a coherent progression through the principal areas of the subject (hydraulics; sediment transport; river morphology; tools and methods; applications of science). Definitive review of the current knowledge of gravel-bed rivers Coverage of both fundamental and applied topics Edited by leading academics with contributions from key researchers Thoroughly edited for quality and consistency to provide coherent and logical progression through the principal areas of the subject.
Download or read book Use of High Spatial Resolution Remote Sensing and GHS for Soil Erosion Modelling written by Nadeem Hashem and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
