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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

2-D modeling of freeze-up processes on the Athabasca River downstream of Fort McMurray, Alberta

Wojtowicz, Agata 06 1900 (has links)
This study is part of a three year project aimed to assess the effects of industrial water withdrawals on the ice regime of the Athabasca River. A 2-D numerical model was used to provide quantitative data for this effort. Freeze-up monitoring was carried out over two years along 80-km of the river from Fort McMurray to Bitumount. Summer bathymetric and winter ice surveys were conducted along with discharge measurements on a 5-km long detailed study reach that exhibited the full range of ice cover initiation processes. The data collected was used to build a CRISSP2D river ice process model for the simulation of freeze-up processes. An extensive parametric assessment was carried out to evaluate the capabilities of the model. Although it was not possible to simulate bridging, the simulated border ice agreed very well with field observations. Limitations of the model are addressed and future research recommendations are included. / Water Resources Engineering
22

Air Injection for River Water Quality Improvement

Zhang, Wenming Unknown Date
No description available.
23

Ensemble of models shows coherent response of a reservoir’s stratification and ice cover to climate warming

Feldbauer, Johannes, Ladwig, Robert, Mesman, Jorrit P., Moore, Tadhg N., Zündorf, Hilke, Berendonk, Thomas U., Petzoldt, Thomas 22 March 2024 (has links)
Water temperature, ice cover, and lake stratification are important physical properties of lakes and reservoirs that control mixing as well as bio-geo-chemical processes and thus influence the water quality. We used an ensemble of vertical onedimensional hydrodynamic lake models driven with regional climate projections to calculate water temperature, stratification, and ice cover under the A1B emission scenario for the German drinking water reservoir Lichtenberg. We used an analysis of variance method to estimate the contributions of the considered sources of uncertainty on the ensemble output. For all simulated variables, epistemic uncertainty, which is related to the model structure, is the dominant source throughout the simulation period. Nonetheless, the calculated trends are coherent among the five models and in line with historical observations. The ensemble predicts an increase in surface water temperature of 0.34 K per decade, a lengthening of the summer stratification of 3.2 days per decade, as well as decreased probabilities of the occurrence of ice cover and winter inverse stratification by 2100. These expected changes are likely to influence the water quality of the reservoir. Similar trends are to be expected in other reservoirs and lakes in comparable regions.
24

<b>Machine Learning And remote sensing applications for lake Michigan coastal processes</b>

Hazem Usama Abdelhady (18309886) 04 April 2024 (has links)
<p dir="ltr">The recent surge in water levels within the Great Lakes has laid bare the vulnerability of the surrounding coastal areas. Over the past few years, communities along the Great Lakes coast have struggled with widespread coastal transformations, witnessing phenomena such as shoreline retreat, alterations in habitat, significant recession of bluffs and dunes, infrastructure and property damage, coastal flooding, and the failure of coastal protection structures. Unlike the ocean coasts, the Great Lakes coastal regions experience a unique confluence of large interannual water level fluctuations, coastal storms, and ice cover dynamics, which complicates the ongoing coastal management endeavors. To address this multifaceted challenge, the interplay between all these factors and their impact on coastal changes should be understood and applied to improve the resilience of Great Lakes coastal areas.</p><p><br></p><p dir="ltr">In this dissertation, several steps were taken to improve knowledge of coastal processes in the Great Lakes, spanning from the initial use of remote sensing for quantifying coastal changes to the subsequent stages of modeling and predicting shoreline changes as well as leveraging machine learning techniques to simulate and forecast influential factors like waves and ice cover. First, a fully automated shoreline detection algorithm was developed to quantify the shoreline changes in Lake Michigan, detecting the most vulnerable areas, and determining the main factors responsible for the spatial variability in the shoreline changes. Additionally, a reduced complexity model was designed to simulate the shoreline changes in Lake Michigan by considering both waves and water level fluctuations, which significantly improved the shoreline changes modeling and forecasting for Lake Michigan. Furthermore, new deep learning-based frameworks based on the Convolution Long Short-Term Memory (ConvLSTM) and Convolution Neural Network (CNN) were introduced to model and extend the current records of wave heights and ice cover datasets, adding 70% and 50% data to the existing waves and ice time series respectively. Finally, the extended waves and ice time series were used to study the long-term trends and the correlation between the interannual water level and waves changes, revealing a statically significant decreasing trend in the ice cover over Lake Michigan of 0.6 days/year, and an increasing trend in the waves interannual variability at Chicago area.</p>

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