Using Spectral Analysis Techniques to Identify Characteristic Scales in Digital Elevation Models

Meandering river floodplains exhibit periodic structures which can be seen in features such as meander bends, point bars, and oxbow lakes. To improve our understanding and better analyze floodplain landscapes created by the dynamics of meandering rivers, characteristic scales need to be identified. Although methods that involve manual measurements of certain floodplain features are of utility, they are limited in their application and are typically very time intensive. Spectral analysis techniques represent an improved approach. For this research, two separate 2D spectral analysis techniques were used: the Fourier transform and the continuous wavelet transform. By using an appropriate theoretical red-noise background spectrum for the landscape, the spectral analysis techniques could provide a power spectrum which is then used to clearly identify the global and local characteristic scales. The results from the analysis of synthetic test images demonstrated such capability of both methodologies, and indicated that both performed similarly although the wavelet transform provides spatial information in addition to scale. The methodologies were then applied to simulated meandering river floodplain of meandering river where two ranges of characteristic scales were identified that corresponded to bend-scale and meander-train scale features. The characteristic meander-scale features also correlated with the surface metrics focal mean, the average elevation within a given area, and rugosity, the ratio between surface area of a given area and the surface area of a completely flat surface. The results show that the spectral analysis techniques can identify characteristic scale of a meander-river floodplain and that the relationship to the surface metrics indicate that it provides information to the topographic structure of the floodplain

Review on the Geophysical and UAV-Based Methods Applied to Landslides

peer reviewedLandslides (LS) represent geomorphological processes that can induce changes over time in the physical, hydrogeological, and mechanical properties of the involved materials. For geohazard assessment, the variations of these properties might be detected by a wide range of non-intrusive techniques, which can sometimes be confusing due to their significant variation in accuracy, suitability, coverage area, logistics, timescale, cost, and integration potential; this paper reviews common geophysical methods (GM) categorized as Emitted Seismic and Ambient Noise based and proposes an integrated approach between them for improving landslide studies; this level of integration (among themselves) is an important step ahead of integrating geophysical data with remote sensing data. The aforementioned GMs help to construct a framework based on physical properties that may be linked with site characterization (e.g., a landslide and its subsurface channel geometry, recharge pathways, rock fragments, mass flow rate, etc.) and dynamics (e.g., quantification of the rheology, saturation, fracture process, toe erosion, mass flow rate, deformation marks and spatiotemporally dependent geogenic pore-water pressure feedback through a joint analysis of geophysical time series, displacement and hydrometeorological measurements from the ground, air and space). A review of the use of unmanned aerial vehicles (UAV) based photogrammetry for the investigation of landslides was also conducted to highlight the latest advancement and discuss the synergy between UAV and geophysical in four possible broader areas: (i) survey planning, (ii) LS investigation, (iii) LS dynamics and (iv) presentation of results in GIS environment. Additionally, endogenous source mechanisms lead to the appearance of deformation marks on the surface and provide ground for the integrated use of UAV and geophysical monitoring for landslide early warning systems. Further development in this area requires UAVs to adopt more multispectral and other advanced sensors where their data are integrated with the geophysical one as well as the climatic data to enable Artificial Intelligent based prediction of LS

Progress Monitoring and Quality Assessment/Quality Control of Construction Projects Using Lidar and BIM

The construction industry is a key contributor to the Gross Domestic Product (GDP) of many countries around the world and is valued at more than $10 trillion globally. Schedule, cost and quality are the main performance measures of construction projects. The primary goal for project stakeholders in the construction industry is to ensure that a project is delivered on time and on budget, while meeting the project specific quality standards. However, cost and schedule overruns, and rework have become the costly standard for most construction projects. In particular, transportation construction projects are very sensitive to cost and schedule overruns due to the magnitude of risk and uncertainty involved. The inaccuracies, inconsistencies, and delays associated with manual collection of project progress data further contribute to the inefficient tracking of resources, activities, and cost, consequently causing issues to be overlooked and leaving them unresolved. Another major issue in the construction industry is related to the assessment of the quality of work in a timely fashion in order to avoid rework. Focusing on measuring the quality of concrete slabs, several concrete surface waviness assessment methods have been developed to overcome the disadvantages of one assessment method over the other. Floor surface waviness assessment over multiple one-dimensional (1D)-survey lines may not accurately reflect the actual condition or waviness of an entire floor. Thus, it can be concluded that the current practices for performing project quality control and progress tracking are prone to errors, labor-intensive, and time-consuming, and there is a need to develop novel, technology supplemented methodologies to improve current project quality control and progress tracking practices. This dissertation proposes two technology-supplemented frameworks for project progress tracking and dimensional quality control, and is comprised of three manuscripts. The first manuscript presents a framework that uses mobile lidar data and four dimensional- (4D-) design models for tracking the progress of bridge construction projects. The framework is capable of determining the completion of individual bridge elements in an accurate and efficient manner, and the progress information is reported as Percentage of Completion (POC). The second manuscript presents a framework that enables assessment of a concrete surface in two-dimensional (2D) domain using the synergy between Terrestrial Laser Scanning (TLS) and Continuous Wavelet Transform (CWT). 2D CWT analysis provides information not only about the periods of the surface undulations, but also the location of such undulations. The third manuscript presents a sensitivity analysis of the impact of various TLS point cloud scanning resolutions on surface waviness results. Furthermore, the surface waviness results obtained using TLS and Unmanned Aerial Vehicles (UAV)-based laser scanning are compared and analyzed

Proceedings Of The 18th Annual Meeting Of The Asia Oceania Geosciences Society (Aogs 2021)

The 18th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2021) was held from 1st to 6th August 2021. This proceedings volume includes selected extended abstracts from a challenging array of presentations at this conference. The AOGS Annual Meeting is a leading venue for professional interaction among researchers and practitioners, covering diverse disciplines of geosciences

River Hydrology, Morphology, and Dynamics in an Intensively Managed, Transient Landscape

Rivers create beautiful patterns and provide drinking water to millions. However an alarming number of rivers in the US and globally are threatened by excess sediment and nutrients. Agricultural rivers draining erodible soils are particularly vulnerable. Rivers of southern Minnesota provide a unique opportunity to study water and sediment dynamics in a naturally vulnerable system. Sediment reduction strategies are needed to ensure biological integrity and adequate water quality. Here, I address the questions: 1) have climate, land use practices, or both affected streamflows in Midwest agricultural rivers?, 2) which streamflows set the rate of river bluff erosion?, and 3) how do sediment supply and transport influence the form and behavior of the lower Minnesota River? Chapter 2 demonstrates, in three agricultural basins, that artificial drainage practices have decreased soil moisture, contributing to increases in streamflow. Chapter 3 quantifies river bluff erosion and identifies erosion by streamflows as the dominant erosion process. Erosion by common floods accomplishes the most cumulative bluff erosion. Bluff erosion contributes sediment to the Minnesota River. Chapter 4 shows how this coarse sediment influences the form and behavior of the Minnesota River. Therefore if flows were reduced, bluff erosion would slow, and the supply sediment to the Minnesota would slow, leading to less streambank erosion. Since streamflows have been increased by agricultural drainage practices, water retention solutions are needed to reduce high flows

Modeling of Soil Erosion and Sediment Transport

The Special Issue entitled “Modeling of Soil Erosion and Sediment Transport” focuses on the mathematical modeling of soil erosion caused by rainfall and runoff at a basin scale, as well as on the sediment transport in the streams of the basin. In concrete terms, the quantification of these phenomena by means of mathematical modeling and field measurements has been studied. The following mathematical models (software) were used, amongst others: AnnAGNPS, SWAT, SWAT-Twn, TUSLE, WRF-Hydro-Sed, CORINE, LCM-MUSLE, EROSION-3D, HEC-RAS, SRC, WA-ANN. The Special Issue contains 14 articles that can be classified into the following five categories: Category A: “Soil erosion and sediment transport modeling in basins”; Category B: “Inclusion of soil erosion control measures in soil erosion models”; Category C: “Soil erosion and sediment transport modeling in view of reservoir sedimentation”; Category D: “Field measurements of gully erosion”; Category E: “Stream sediment transport modeling”. Most studies presented in the Special Issue were applied to different basins in Europe, America, and Asia, and are the result of the cooperation between universities and/or research centers in different countries and continents, which constitutes an optimistic fact for the international scientific communication

Seismic Waves

The importance of seismic wave research lies not only in our ability to understand and predict earthquakes and tsunamis, it also reveals information on the Earth's composition and features in much the same way as it led to the discovery of Mohorovicic's discontinuity. As our theoretical understanding of the physics behind seismic waves has grown, physical and numerical modeling have greatly advanced and now augment applied seismology for better prediction and engineering practices. This has led to some novel applications such as using artificially-induced shocks for exploration of the Earth's subsurface and seismic stimulation for increasing the productivity of oil wells. This book demonstrates the latest techniques and advances in seismic wave analysis from theoretical approach, data acquisition and interpretation, to analyses and numerical simulations, as well as research applications. A review process was conducted in cooperation with sincere support by Drs. Hiroshi Takenaka, Yoshio Murai, Jun Matsushima, and Genti Toyokuni