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Applying a two-dimensional hydrodynamic model to estimate fish stranding risk downstream from a hydropeaking hydroelectric station
No full textThis is the peer reviewed version of the following article: Sarah E. Glowa, Andrea J. Kneale, Douglas A. Watkinson, Haitham K. Ghamry, Eva C. Enders, Timothy D. Jardine, Applying a two-dimensional hydrodynamic model to estimate fish stranding risk downstream from a hydropeaking hydroelectric station, Ecohydrology, 10.1002/eco.2530, 16, 4, (2023)., which has been published in final form at 10.1002/eco.2530. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.Fisheries and Oceans Canada’s Freshwater Habitat Science Initiative (FHIN)Peer ReviewedFish stranding is of global concern with increasing hydropower operations using hydropeaking to respond to fluctuating energy demand. Determining the effects hydropeaking has on fish communities is challenging because fish stranding is dependent on riverscape features, such as topography, bathymetry and substrate. By using a combination of physical habitat assessments, hydrodynamic modelling and empirical data on fish stranding, we estimated the number of fish stranding over a 5-month period for three model years in a large Prairie river. More specifically, we modelled how many fish potentially stranded during the years 2019, 2020 and 2021 across a 16 km study reached downstream from E.B. Campbell Hydroelectric Station on the Saskatchewan River, Canada. Fish stranding densities calculated from data collected through remote photography and transect monitoring in 2021 were applied to the daily area subject to drying determined by the River2D hydrodynamic model. The cumulative area subject to change was 90.05, 53.02 and 80.74 km2 for years 2019, 2020 and 2021, respectively, from June to October. The highest number of stranded fish was estimated for the year 2021, where estimates ranged from 89,800 to 1,638,000 individuals based on remote photography and transect monitoring fish stranding densities, respectively, 157 to 2,856 fish stranded per hectare. Our approach of estimating fish stranding on a large scale allows for a greater understanding of the impact hydropeaking has on fish communities and can be applied to other riverscapes threatened by hydropeaking.Fish stranding is of global concern with increasing hydropower operations using hydropeaking to respond to fluctuating energy demand. Determining the effects hydropeaking has on fish communities is challenging because fish stranding is dependent on riverscape features, such as topography, bathymetry and substrate. By using a combination of physical habitat assessments, hydrodynamic modelling and empirical data on fish stranding, we estimated the number of fish stranding over a 5-month period for three model years in a large Prairie river. More specifically, we modelled how many fish potentially stranded during the years 2019, 2020 and 2021 across a 16 km study reached downstream from E.B. Campbell Hydroelectric Station on the Saskatchewan River, Canada. Fish stranding densities calculated from data collected through remote photography and transect monitoring in 2021 were applied to the daily area subject to drying determined by the River2D hydrodynamic model. The cumulative area subject to change was 90.05, 53.02 and 80.74 km2 for years 2019, 2020 and 2021, respectively, from June to October. The highest number of stranded fish was estimated for the year 2021, where estimates ranged from 89,800 to 1,638,000 individuals based on remote photography and transect monitoring fish stranding densities, respectively, 157 to 2,856 fish stranded per hectare. Our approach of estimating fish stranding on a large scale allows for a greater understanding of the impact hydropeaking has on fish communities and can be applied to other riverscapes threatened by hydropeaking
EVALUATING PASSIVE EARTH PRESSURE TRENDS OF LARGE-SCALE PLATE LOAD TESTING OF GEOGRIDSTABILISED AGGREGATE LAYERS OVER CLAY
Get PDFThe manuscripts presented in this thesis focus on two main topics. The first manuscript describes
the procedures and material characterisation of the large-scale plate load testing, while the
second manuscript focuses on relating the large-scale plate load tests to Meyerhof’s punching
shear bearing capacity theory. The abstracts for the two manuscripts are presented below.
Part 1: Large-Scale Plate Load Testing of Geogrid-Stabilised Aggregate Layers over Clay
Geogrid stabilised aggregate layers are used to increase the bearing capacity of weak subgrade
material. Applications of these geogrid-aggregate composite layers include, but are not limited
to, temporary working platforms, road construction, and railway ballast. The inclusion of the
geogrid in aggregate creates an interlocked structure that improves the bearing capacity of the
composite layer. In this study, what we believe to be the largest full-scale controlled plate load
testing was carried out near Clavet, Saskatchewan, to test various geogrid-aggregate composite
layers. A 1m2
plate pushed stabilised and non-stabilised aggregate pads within a pre constructed
trench above a silty clay past their ultimate bearing capacity using a hydraulic cylinder with a
capacity of 100 tonnes. Load and displacement were measured directly. The cylinder was
attached below a moveable steel platform equipped with counterweights to account for the large
loads required to fail the testing pads. Analyses, including cone penetration testing,
photogrammetry, and intensive material characterisation, were done before and after plate load
testing.
Part 2: Evaluation of Meyerhof’s Semi-Empirical Bearing Capacity Solution Using Large
Scale Plate Load Testing of Geogrid Stabilised Working Platforms
Increasing the bearing capacity of aggregate layers placed over soft subgrades by stabilising the
aggregate with geogrids is a relatively novel practice with limited standardized design
procedures. This is caused by the growing number of stabilising geogrid products that are
becoming available as well as how each of these products will have a unique interaction with the
geogrid used in design. The research presented relates large-scale plate load testing results to
Meyerhof’s widely used punching shear bearing capacity theory of a strong layer overlying a
weak layer. Mobilisation trends for two different thicknesses of unstabilised aggregate layers are
compared to Meyerhof’s originally proposed trend of δ = 0.667φ. Mobilisation trends of the
aggregate stabilised with three different types of geogrid are then determined
Phytoplankton dynamics in relation to turbidity and other environmental factors in Lake Diefenbaker
No full textClimate warming (i.e., drought, flooding, rising temperature) and the increased demand for water from reservoirs promote algal blooms in reservoirs. Lake Diefenbaker (LD) is a poorly studied reservoir in the Canadian Prairies that is susceptible to episodic algal blooms, especially in summer and fall following calm periods. These booms are of concern to residents. LD has experienced variable flow from its major tributary, the South Saskatchewan River (SSR), which receives its water from the melting of snow-pack in the Rocky Mountains (Alberta). It is expected that as the Canadian Prairies continue to undergo climate change, lakes located in this region are predicted to experience more frequent extreme events. Water withdrawal from the reservoir is an additional problem and plans are underway to increase water abstraction from LD for irrigation. But our knowledge remains unclear about how climate variability (i.e., extreme hydro-meteorological events such as drought and flooding and associated turbidity) due to climate warming and human activities will influence the phytoplankton dynamics in LD. Therefore, reconstructed historic turbidity and chlorophyll-a levels from Landsat-images, and long-term, extensive field observations were used to investigate how algal biomass and composition with turbidity will respond under different hydro-meteorological and limnological conditions in LD.
The SSR is naturally turbid with clay-sized particles with inherently low settling velocity. However, long-term records of turbidity are not available to fully understand the factors associated with it in Lake Diefenbaker. Therefore, I reconstructed historic turbidity levels using Landsat-imagery on LD and examined the factors that were associated with it (Chapter 2). Estimated turbidity decreased spatially and temporally which is likely associated with the decline in the SSR flow and the settling of suspended sediments. Tributary flow and wind speed explained 64 %, 54 % and 69 % of the variability in estimated turbidity levels in the riverine zone, in the transition zone and in the entire reservoir, respectively. The relationship between estimated turbidity and wind speed (WS) may be associated with the re-suspension of bottom sediment at the upper reach of LD. I observed high turbidity in 2002 that exceeded other estimates of turbidity. Because a prolonged drought preceded 2002, the high estimated turbidity may be related to an increase in sediment loads from the SSR flow and an increase in shoreline erosion from a rise in LD’s water level, this is novel information that would have been impossible to obtain without Landsat-imagery.
Hydrological drought as characterized by low river inflow rate, and in turn, low water level (WL) and greater water residence time (WRT), may support greater algal biomass and blooms in lakes. To test the hypothesis that periods of lower inflows are related to increased algal biomass in LD, I examined the association between summer chlorophyll-a and hydrologic variables. A 31-year period of hydrologic data and estimated chlorophyll-a (i.e., derived from Landsat imagery) was examined (Chapter 3). Summer estimated chlorophyll-a increased as WL decreased in late spring/early summer (r2adj = 0.30, P = 0.00081). This inverse relationship may be a function of improved light conditions and internal nutrient loading. Summer estimated chlorophyll-a had a weak, inverse relationship with late spring/early inflow rate (r2adj = 0.12, P = 0.0315) that was likely driven by an extreme high flow event in 2011. Summer estimated chlorophyll-a was not significantly related to WRT (r2adj = 0.06, P = 0.1), which may be due to the limited variability in WRT and the size of LD.
Reduced water levels in reservoirs due to drought, or water abstraction, or both are associated with high cyanobacterial abundance in reservoirs. Because Lake Diefenbaker has experienced reduced water levels associated with drought and plans are underway to increase water abstraction from LD for irrigation, I used a nine-year dataset that comprised a drought year (1984), four consecutive high flow years (2011 to 2014), and four subsequent low flow years (2015 to 2018) to investigate how these changes could affect the major phytoplankton groups and cyanobacterial community (Chapter 4). Diatoms and cryptomonads dominated the algal community under low and high flow years. Diatoms were associated with greater mixing in late spring and fall, whereas the cryptomonads were related to the high nutrients from spring flow. Cyanobacteria dominated the phytoplankton (79.3% of the total biomass) under drought, which may be associated with thermocline deepening and subsequent internal loading of nutrients as observed in other reservoirs. Microcystis, a potential bloom-forming and toxin-producing genus, was dominant during the drought and correlated with reduced WL, increased air temperature, and moderate WS. Although its biomass was low, another potential bloom-forming and toxin-producing genus, Aphanizomenon, was present in low and high flow years. Aphanizomenon was correlated with decreased inflow rate and increased particulate carbon to particulate phosphorus ratios, which may be related to improved light conditions and to their ability to cope with P limitation.
In conclusion, these results highlight that LD is vulnerable to an increase in potential toxic cyanobacteria species during lower water levels. It is expected that climate variability will lead to more frequent extreme events (i.e., drought) that will affect reservoirs around the globe, including those in the Canadian Prairies, due to climate warming. Moreover, water abstraction from reservoirs to meet the needs of the growing human population poses an additional challenge. Such reduction in water level due to drought and the associated increase in water abstraction in the SSR basin will cause further deterioration of water quality (algal blooms) in LD
Modelling Transport and Fate of Copper and Nickel across the South Saskatchewan River Using WASP—TOXI
No full text© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).University of Saskatchewan’s New Faculty Graduate Student Support Program (NFGSSP), Global Water Futures (GWF), Canada First Research Excellence Funds, Canada Foundation for Innovation (CFI)—38581Peer ReviewedThe South Saskatchewan River (SSR) is one of the most important river systems in Saskatchewan and, arguably, in Canada. Most of the Saskatchewan residents, industries, and powerplants depend on the SSR for their water requirements. An established 1D modelling approach was chosen and coupled with the Hydrologic Engineering Center’s River Analysis System (HEC-RAS). The WASP (Water Quality Analysis Simulation Program) stream transport module, TOXI, is coupled with flow routing for free-flow streams, ponded segments, and backwater reaches and is capable of calculating the flow of water, sediment, and dissolved constituents across branched and ponded segments. Copper and nickel were chosen as two metals with predominantly anthropogenic (agriculture, mining, and municipal and industrial waste management) and geogenic (natural weathering and erosion) sources, respectively. Analysis was carried out at ten different sites along the South Saskatchewan River, both upstream and downstream of the City of Saskatoon, in the years 2020 and 2021. Model performance was evaluated by comparing model predictions with concentrations of copper and nickel measured in a previously published study. The model performed well in estimating the concentrations of copper and nickel in water samples and worked reasonably well for sediment samples. The model underestimated the concentration values at certain segments in both water and sediment samples. In order to calibrate the model more accurately, extra diffusive contaminant loads were added. While several default parameter values had to be used due to the unavailability of primary historical data, our study demonstrates the predictive power of combining WASP—TOXI and HEC-RAS models for the prediction of contaminant loading. Future studies, including those on the impacts of global climate change on water quality on the Canadian prairies, will benefit from this proof-of-concept study
"It's not just for me, it's also for my community": Toward the Decommodification of Self-Care Through Racialized Activists' Care Practices
No full textTo promote change, activists must confront the suffering of their communities, but this process can weigh heavily on them and contribute to burnout. The burden is even heavier for racial minority activists who combat additional stressors associated with discrimination. While many activist organizations promote community care, their conceptualization of community wellness competes with the individual wellness promised by luxury self-care products, inaccessible to those facing financial barriers. The present study challenges this buy-in model of self-care. Using participatory qualitative methods and grounded theory, I have examined how racialized activists in Saskatoon develop their own care practices. Driven by a desire to live their values, participants developed their care practices in five stages: Developing Activist Values, Belonging, Participating in Community Care, Protective Self-Care, and Restorative Self-Care. By the end of the process, participants were sustaining long-term wellness strategies by exercising their values with the support of their communities. The results present a conceptualization of personal wellness that resists commodification by being grounded in community, personal values, and political defiance. The work discusses the implications for conceptualizations of well-being, and directions for future research
Combination Therapies to Target EphA2 and EGFR Expressing Tumors.
No full textThe abstract of this item is unavailable due to an embargo
The features of MCSs in Canada and the United States using convection-permitting climate models forced by ERA5 and CMIP6
No full textGlobal climate models (GCMs) are tools that help us understand how the climate works and how it might change in the future. They are based on mathematical equations that describe the physical processes of the atmosphere, ocean, land and ice. The Coupled Model Intercomparison Project (CMIP) is a project that compares different GCMs and their results. Regional Climate Models (RCMs) are similar to GCMs, but they focus on a smaller area and have more details. However, RCMs rely on parameterization schemes to represent subgrid-scale processes that cannot be resolved by the model grid. Parameterization schemes introduce uncertainties and errors in the model results, especially for complex and nonlinear processes like convection and cloud formation. Convection-permitting climate models (CPCMs) are a type of RCMs that can capture small-scale weather features like thunderstorms and clouds without using parameterization schemes. By using a finer grid resolution, CPCMs can explicitly resolve these processes and reduce the uncertainties and biases from parameterization schemes. This makes CPCMs more accurate and reliable for simulating the climate and its changes. Mesoscale Convective Systems (MCSs) are large groups of thunderstorms that can produce heavy rain, hail and strong winds. They are important for the water cycle and the climate of the Rocky Mountains in Canada and the United States. The main goals of this study are to use CPCMs to 1) analyze how well they represent the long-term features of MCSs before they occur in the current climate and 2) project how these features may vary in the future under different greenhouse gas emission scenarios.
This study aimed to improve our knowledge of the features of MCSs in current and future climates using CPCMs. However, the study was limited by the data availability of both the input forcing datasets and observational datasets. The study had three main objectives: 1) to understand the climatological characteristics of MCSs in the central United States (2004 - 2018), 2) to examine the regional features of MCSs over the Canadian Prairies (2009 - 2018), and 3) to project the future climate in the central United States (2076 - 2100) for summer seasons.
Due to the computational resources required to run the CPCMs, the domain size and analysis period were restricted to 24 degrees in longitude and 20 degrees in latitude, respectively, as well as the summer season.
This constraint prevented the study from covering longer periods or larger domains for each objective. The study analyzed meteorological parameters that represented both dynamical and thermodynamic conditions. However, it did not consider physical factors, even though the higher resolution CPCMs showed agreement with previous studies. One of the benefits of the study was that it provided detailed information about the conditions preceding convection when identifying daytime and nighttime MCSs. The findings of the study also yielded important insights into the regional features of MCSs but were extremely restricted to statistical results, lacking a comprehensive analysis of the physical aspects. However, it is essential to interpret these findings with caution, as they may not fully capture the entire range of variability and uncertainty of MCSs in different climates and regions. Furthermore, the absence of explicitly simulated convection initiation limits their physical meaning
Exploring the Anatomy of Ethereum Based Phishing
Get PDFThe abstract of this item is unavailable due to an embargo
Effects of co-inoculation of Delftia acidovorans RAY209 on the growth of Bradyrhizobium diazoefficiens USDA110 inoculated Glycine max
Get PDFToday's global prosperity and food abundance has largely been brought about by the extensive use of chemical fertilizers, and it is predicted that even more pressure on agrifood systems will occur in the coming decades. The cumulative impacts of this increased pressure will be driven by continued population growth, an unprecedented and growing demand for high quality protein, environmental degradation caused by chemical fertilizers, and also be the need for agriculture to be more sustainable.
Inoculating crops with plant growth-promoting rhizobacteria (PGPR) has emerged to fill in the gap between the growing demand for food and sustainable agriculture as it promotes plant growth, reduces crop susceptibility to abiotic and biotic stress, and ultimately facilitates producing foods in a sustainable manner. Besides the well-established and widely-applied legume-rhizobia interaction, the co-inoculation of soybean with Bradyrhizobium and other plant PGPR has gain increasing popularity attributed to the observed synergistic effects that result in improved plant growth promotion and stress tolerance. The objective of the current investigation was to examine whether co-inoculating soybean (Glycine max L. (Merr.) with Bradyrhizobium diazoeffeciens USDA110 and PGPR Delftia acidovorans RAY209 can enhance plant growth and enhance stress tolerance, as well as to identify the underlying mechanisms.
The first study successfully cultured and tested the salt tolerance of USDA110 and RAY209 in vitro where RAY209 exhibit good tolerance in salt relative to USDA110. The effect of different inoculation methods on plant growth and stress tolerance was then examined in a gnotobiotic system. Confocal laser scanning microscopy confirmed the host specificity between inoculant strains and soybean. Although no significant differences were found in growth parameters between soybean roots inoculated with USDA110 and RAY209+USDA110, RAY209 produced considerable amounts of indole-3-acetic acid (IAA), a phytohormone that can potentially stimulate plant growth and cause modification of root architecture. Differential transcriptome analysis of 30-day inoculated seedlings revealed that stress conditions had a larger effect on gene expression in soybean roots than inoculation method. However, co-inoculation with RAY209 and USDA110 did reveal the increased expression of genes associated with xyloglucan catabolism and subsequent cell wall expansion, which could initiate plant cell growth and active proline metabolism under salt stress conditions. These findings suggest that RAY209 may play a crucial role in plant growth-promotion (PGP), particularly in soybean-Bradyrhizobia symbiosis. Further studies are necessary to fully unravel the extent of IAA production by RAY209 in vivo and its effect on plant growth and the biological processes related to root morphology