Slave River Research Articles

Assessing Ice Break-Up Trends in Slave River Delta through Satellite Observations and Random Forest Modeling

Assessing Ice Break-Up Trends in Slave River Delta through Satellite Observations and Random Forest Modeling

Dissolved polycyclic aromatic compounds in Canada’s Athabasca River in relation to Oil Sands from 2013 through 2019

The Canada-Alberta Oil Sands Monitoring (OSM) Program began long-term surface water quality monitoring on the lower Athabasca River in 2012. Sampling of low level, bio-accumulative polycyclic aromatic compounds (PACs) targeted a suite of parent and alkylated compounds in the Athabasca River (AR) mainstem using semi-permeable membrane devices (SPMDs). Samples were collected along a gradient from upstream reference near Athabasca, Alberta, through exposure to the Athabasca oil sands deposit (AOSD), various tributary inflows, and mining activities within the OSMA, to downstream recovery near Wood Buffalo National Park (WBNP) and reference on the Slave River. The program adapted over the years, shifting in response to program review and environmental events. The AOSD chemical fingerprint was present in samples collected within the AOSD, through the oil sands mineable area (OSMA), downstream to recovery from 2013 to 2019. PACs were dominated by alkylated phenanthrenes/anthracenes (PAs) and dibenzothiophenes (Ds), with elevated levels of alkylated fluorenes (Fs), naphthalenes (Ns), fluoranthenes/pyrenes (FlPys) and benzo[a]anthracenes/chrysenes (BaACs), increasing in concentration from C1 < C2 < C3 < C4. Concentrations of these petrogenic PACs were at their highest within the OSMA and downstream of tributaries. The AOSD fingerprint was absent from sites located outside of the influence of the AOSD and downstream of the Peace-Athabasca Delta on the Slave River. PAC concentrations in the AR increased with mainstem discharge and loadings from tributaries, were moderated by the PAD, and diluted by the Peace River. This work bolsters the baseline PAC information previously reported for the Athabasca River and waters downstream, reporting 7 years of data, from all sites within the mainstem monitoring program, and exploring potential regional and hydrological drivers of these between sites and over time.

Remote sensing of large wood in high‐resolution satellite imagery: Design of an automated classification work‐flow for multiple wood deposit types

AbstractWood researchers increasingly rely on remote‐sensing products to augment field information about wood deposits in river corridors. The availability of very high‐resolution (&lt;1 m) satellite imagery makes capturing wood over greater spatial extents possible, but previous studies have found difficulty in automatically extracting wood deposits due to the challenge in distinguishing wood from spectrally similar corridor features such as sand. We also lack knowledge on the spectral properties of different wood deposit types in multiple depositional environments. In this work, we explore image classification work‐flows for four wood deposit types in three North American environments: in‐channel jams deposited in the Tatshenshini River in Alaska, USA; a wood raft on the Slave River in Northwest Territories, Canada; and wood deposited along a lakeshore and coastal embayment in the Mackenzie River Delta in Northwest Territories, Canada. We compare classification results of object‐based and pixel‐based image analysis with supervised [support vector machine (SVM)] and unsupervised (ISO clustering) classifiers. We evaluate several accuracy assessment parameters and achieve overall classification accuracies of 65–99%, showing automated image classification is a possible approach for analysing wood across larger areas. We also find that wood sensitivity in the classification ranged from 0 to 95%, indicating that some techniques are better suited to wood capture than others. We find that supervised classification produced more accurate wood maps, though there is large variation in classification outcomes across environments related to spatial arrangement of wood in the landscape. We discuss the influence of depositional environment on classification and provide recommendations for designing a wood classification work‐flow.

Genetic Assessment of Inconnu (Stenodus leucichthys) in Great Slave Lake, Northwest Territories, Canada

Inconnu (Stenodus leucichthys) is a large freshwater migratory coregonid species that is commercially fished in some parts of its range. In Great Slave Lake, NT, Inconnu are one species that is caught in a mixed species gillnet fishery that is subject to restrictive management because four of the seven known stocks are declining or have been extirpated. The seven known Inconnu stocks have been identified based on the river systems that support or once supported a spawning population. To help identify key geographic areas for harvest control and other management approaches, we estimated the genetic diversity and population genetic structure of Inconnu in this area with 17 microsatellite loci. Temporal and spatial genetic structure was examined in four river systems, lower and upper Mackenzie River, Buffalo River, Slave River and Marian River/Lake and within Great Slave Lake. Analyses suggested that genetic diversity was greater in lower/upper Mackenzie River populations compared to populations in Great Slave Lake. Genetic structure was temporally stable at all locations except one, and spatial structure was found with significant isolation by distance detected among locations. Bayesian clustering analysis suggested five genetic groups of Inconnu, one in the lower and upper Mackenzie River and four within Great Slave Lake. The substructuring within Great Slave Lake included a genetic group representing fish collected in the lake itself. In addition, three genetic groups corresponded to river systems (Buffalo River, Marian River/Lake, Slave River), indicating that each river has genetically distinct Inconnu populations. These results suggest that the sustainability of Inconnu in and around Great Slave Lake depends upon maintaining stocks associated with river systems, especially those that are geographically disparate.

Concentrations of Metals in Fishes from the Athabasca and Slave Rivers of Northern Canada.

There is growing concern about possible effects of exploitation of the Alberta Oil Sands on the ambient environment, including possible effects on populations of fishes in the Athabasca River and farther downstream in Lake Athabasca and the Slave River. In the present study, concentrations of metals in dorsal muscle tissue of 5 fish species-goldeye, northern pike, walleye, whitefish, and burbot-from the Slave, Peace, and Athabasca Rivers were quantified. A suite of 25 metals including As, Hg, Se, Tl, and V was analyzed. Most metals exhibited no significant variations in concentration among locations. Concentrations of 5 metals, As, Hg, Se, Tl, and V, revealed significant variations among locations and were of sufficient magnitude to be of interest. Concentrations of Hg did not vary significantly among locations; however, because it was detected at concentrations of concern and the use of the selected fishes was a local source of food for humans and pets, it was of interest. Concentrations of As, Se, Tl, and V in dorsal muscle of certain fishes in the farthest downstream sites on the Slave River were greater than those in the same tissues and species in the farther upstream sites on the Peace and Athabasca Rivers. This phenomenon was most prevalent with Tl and to a lesser extent with As and Se. Nevertheless, concentrations were not of concern for the health of human consumers. Although metals did not appear to be increased in fish in the Alberta Oil Sands region in the present study, further research is needed to understand the potential impacts. Environ Toxicol Chem 2020;39:2180-2195. © 2020 SETAC.

Tenets of Community-Engaged Scholarship Applied to Delta Ways Remembered

This essay reviews challenges posed to community-engaged scholars regarding tenure/promotion processes in Canadian universities, with a note to characteristics of community-engaged scholarship that were developed by Catherine Jordan (2007) to address gaps in academic assessment of engaged scholarship. These characteristics are: clear goals, adequate preparation, appropriate methods: scientific rigor and community engagement, significant results/impact, effective presentation/dissemination, reflective critique, leadership and personal contribution, and consistently ethical behavior. These are then applied to a non-peer reviewed work that describes the cumulative effects of environmental change for people in the Slave River Delta Region of the North West Territories, Canada. The reader is asked to view Delta Ways Remembered, a 13-minute video employing an enhanced e-storytelling technique to share and disseminate traditional knowledge about the delta from a compendium of people as a single-voiced narrative. The purpose is to highlight the scholarship underlying non-traditional academic expositions not readily assessed under current paradigms of academic evaluation. This essay strives to illustrate how Jordan’s characteristics can be applied to evaluate non-peer reviewed scholarly work, and also to share rewards and challenges associated with the harmonious blending of Indigenous and western knowledge addressing societal/environmental issues identified by the Indigenous community.

Water Surface Temperature and Suspended Sediment Concentration (SSC) Retrieval from Landsat Imagery, Northwest Territories, Canada

This paper presents water surface temperature retrieval using Landsat thermal band and meteorological ancillary data. The algorithms were tested using Landsat-5/7/8 imagery acquired at different study sites along the Slave River and Mackenzie River of the Northwest Territories (NWT), Canada. By comparing the retrieved temperatures with in situ water temperatures, in-depth validation of one reliable retrieved technique was successfully demonstrated. The method yielded a mean absolute error (MAE) in the range of 1.00–1.38 °C, over 7 validation locations in a 2-year observation period. This paper also presents a method to estimate suspended sediment concentration (SSC) in the Slave River region using Landsat-8 imagery. The numerical relationships between in situ SSC measurements and water-leaving reflectance in visible and near-infrared (NIR) bands were investigated through regression fitting. The SSC estimation results using the retrieved models were analyzed and validated, the NIR model was found to generate the smallest estimation errors with a MAE of 7.98 mg/L using leave-one-out (LOO) uncertainty assessment. An operational web-based tool for water surface temperature and SSC mapping based on the algorithms validated during this study has been developed to address additional monitoring requirements of the NWT communities. The design and implementation of this tool is also described.

Vanadium and thallium exhibit biodilution in a northern river food web

Trophic transfer of contaminants dictates concentrations and potential toxic effects in top predators, yet biomagnification behaviour of many trace elements is poorly understood. We examined concentrations of vanadium and thallium, two globally-distributed and anthropogenically-enriched elements, in a food web of the Slave River, Northwest Territories, Canada. We found that tissue concentrations of both elements declined with increasing trophic position as measured by δ15N. Slopes of log [element] versus δ15N regressions were both negative, with a steeper slope for V (−0.369) compared with Tl (−0.099). These slopes correspond to declines of 94% with each step in the food chain for V and 54% with each step in the food chain for Tl. This biodilution behaviour for both elements meant that concentrations in fish were well below values considered to be of concern for the health of fish-eating consumers. Further study of these elements in food webs is needed to allow a fuller understanding of biomagnification patterns across a range of species and systems.

Effects of River Geomorphology on River Ice Freeze-up and Break-up Rates Using MODIS Imagery

Evaluating driving factors of river ice freeze-up and break-up is critical for the understanding associated with river ice processes, as well as for providing a means to predict potential natural hazards of river ice formation or deformation. Spatiotemporal changes from fifteen years (2000–2015) of MODIS reflectance band 2 images were analyzed in pixel-wise linear regressions to be used as an indicator of the rates of ice freeze-up and break-up along the Slave River (Canada). The random forest algorithm was used to model the rates using river corridor slope, effective width, shape, and sinuosity as a set of predictor variables. The results reveal that the selected predictor variables can explain about 80% and 70% of the variations in ice freeze-up and break-up rates along the Slave River respectively. The slope was the most important factor in determining both freeze-up and break-up rates, followed by shape, effective width, and sinuosity. The spatiotemporal patterns of river freeze-up and ice-cover break-up obtained from the analysis of MODIS data and geomorphological variables show strong agreement with ground observations and hydrometeorological conditions along the Slave River.

Potential of RADARSAT-2 to Improve Ice Thickness Calculations in Remote, Poorly Accessible Areas: A Case Study on the Slave River, Canada

River ice plays an important role in high latitude regions, and ice thickness is an important consideration to local residents as well as hydrologists. Two approaches, measurement (both remotely sensed and direct) and numerical calculations, are common methods used for ice thickness quantification. Measurement of ice thickness using SAR remote sensing approaches is still very challenging due to the low signals in thermal ice and limited penetration capability of C-band on consolidated ice covers. The numerical calculation can provide reasonable ice thickness estimation at a specific location but not the spatial variation. To carry out ice thickness estimations, numerous equations were proposed for numerical calculation. The Ashton equation, incorporating properties of ice and snow cover, was selected to determine the ice thicknesses along the Slave River in Canada. A framework (IceThick-RS) is proposed in this study, which incorporates polarimetric parameters of RADARSAT-2 images (quad-pol mode and C-band) into the ice thickness model. This framework was applied to estimate ice thicknesses along the Slave River. Direct measurements, gathered during the winter of 2014–2015, were used to calibrate the model. The results show that the IceThick-RS framework can be used to carry out river ice thickness estimation, especially in poorly accessible regions.

The Big Book of Canada: Exploring the Provinces and Territories by C. Moore

The Big Book of Canada: Exploring the Provinces and Territories by C. Moore

Monitoring river ice cover development using the Freeman–Durden decomposition of quad-pol Radarsat-2 images

The monitoring of river ice development is a crucial guidance indicator to establish safe crossings along river ice covers. This is the first study, based on our knowledge, to understand the interactions between river ice cover structures and radar signals and to further monitor ice development using C-band synthetic aperture radar images. The study was applied to the Slave River, Canada, using the Freeman–Durden decomposition of quad-pol C-band Radarsat-2 FQ14W images and ice core crystallography analysis. Results demonstrate that the combination of volume and surface scattering can be used to monitor ice cover development that cannot be interpreted from single polarization images, such as Radarsat-2 spotlight images used in this study. These results indicate that the decomposed quad-pol Radarsat-2 images can provide a more effective guide than the single-pol Radarsat-2 SLA images to select safe ice transportation routes. This decomposition approach can be extended to other snow and ice covered rivers.

Coherence of Radarsat-2, Sentinel-1, and ALOS-1 PALSAR for monitoring spatiotemporal variations of river ice covers

ABSTRACTMonitoring spatiotemporal variations of river ice covers is critical for selecting safe ice transportation routes. The coherence of synthetic aperture radar (SAR) interferometry (InSAR) conveys important information on variations of river ice characteristics. However, limited research has been conducted to determine the coherence of multi-frequency L-band ALOS-1 PALSAR, C-band Sentinel-1, and Radarsat-2 images, for such applications. This study was piloted using imagery acquired from the Slave River Delta, Canada, to fill this knowledge gap. The findings were validated using ice core data extracted near Fort Smith. The results indicate that the revisit interval of the satellite is a governing factor of InSAR coherence loss. The ALOS-1 PALSAR images have the smallest coherence mainly due to the 46-day revisit interval and are the least promising for monitoring spatiotemporal variations of river ice covers. Coherence of both Sentinel-1A with a 12-day revisit interval and Radarsat-2 images with a 24-day revisit interval is an important aid for determining safe ice crossings.

RADARSAT-2-based digital elevation models derived from InSAR for high latitudes of northern Canada

The accuracy of digital elevation models (DEMs) plays an important role in many terrain-related applications, particular in high northern latitudes where there is uncertainty in DEMs. Using the interferometric synthetic aperture radar techniques, this study examined how different RADARSAT-2 beam modes can be used to generate DEMs with high accuracy. Using a conventional interferometry method, the Spotlight DEM shows the highest accuracy among all studied DEM products, with the root-mean-square error (RMSE) ranging from 13.9 to 17.4 m, followed by the F0W3 DEM and U26W2 DEM. The error sources in DEM generation due to uncertainty in perpendicular baseline and atmospheric delay are likely more important than the random phase noise caused by volume scattering and environmental changes during synthetic aperture radar (SAR) acquisitions. The small baselines subset (SBAS) method did not significantly improve DEM quality due to the limitation of the number of SAR images in this study. The integration of both Spotlight conventional DEMs and SBAS DEM considerably improved results yielding high-quality DEMs for the study area, with an RMSE of 9.7 m. Further studies are necessary to quantitatively evaluate the effects of surface motion as well as the orbital and atmospheric errors on the DEM accuracy. The Slave River Delta in the Northwest Territories of Canada was used as a test case.

Open-water and under-ice seasonal variations in trace element content and physicochemical associations in fluvial bed sediment.

Across the circumpolar world, intensive anthropogenic activities in the southern reaches of many large, northward-flowing rivers can cause sediment contamination in the downstream depositional environment. The influence of ice cover on concentrations of inorganic contaminants in bed sediment (i.e., sediment quality) is unknown in these rivers, where winter is the dominant season. A geomorphic response unit approach was used to select hydraulically diverse sampling sites across a northern test-case system, the Slave River and delta (Northwest Territories, Canada). Surface sediment samples (top 1 cm) were collected from 6 predefined geomorphic response units (12 sites) to assess the relationships between bed sediment physicochemistry (particle size distribution and total organic carbon content) and trace element content (mercury and 18 other trace elements) during open-water conditions. A subset of sites was resampled under-ice to assess the influence of season on these relationships and on total trace element content. Concentrations of the majority of trace elements were strongly correlated with percent fines and proxies for grain size (aluminum and iron), with similar trace element grain size/grain size proxy relationships between seasons. However, finer materials were deposited under ice with associated increases in sediment total organic carbon content and the concentrations of most trace elements investigated. The geomorphic response unit approach was effective at identifying diverse hydrological environments for sampling prior to field operations. Our data demonstrate the need for under-ice sampling to confirm year-round consistency in trace element-geochemical relationships in fluvial systems and to define the upper extremes of these relationships. Whether contaminated or not, under-ice bed sediment can represent a "worst-case" scenario in terms of trace element concentrations and exposure for sediment-associated organisms in northern fluvial systems. Environ Toxicol Chem 2017;36:2916-2924. © 2017 SETAC.

Using Remote Sensing Data to Parameterize Ice Jam Modeling for a Northern Inland Delta

The Slave River is a northern river in Canada, with ice being an important component of its flow regime for at least half of the year. During the spring breakup period, ice jams and ice-jam flooding can occur in the Slave River Delta, which is of benefit for the replenishment of moisture and sediment required to maintain the ecological integrity of the delta. To better understand the ice jam processes that lead to flooding, as well as the replenishment of the delta, the one-dimensional hydraulic river ice model RIVICE was implemented to simulate and explore ice jam formation in the Slave River Delta. Incoming ice volume, a crucial input parameter for RIVICE, was determined by the novel approach of using MODIS space-born remote sensing imagery. Space-borne and air-borne remote sensing data were used to parameterize the upstream ice volume available for ice jamming. Gauged data was used to complement modeling calibration and validation. HEC-RAS, another one-dimensional hydrodynamic model, was used to determine ice volumes required for equilibrium jams and the upper limit of ice volume that a jam can sustain, as well as being used as a threshold for the volumes estimated by the dynamic ice jam simulations using RIVICE. Parameter sensitivity analysis shows that morphological and hydraulic properties have great impacts on the ice jam length and water depth in the Slave River Delta.

Ecological patterns of fish distribution in the Slave River Delta region, Northwest Territories, Canada, as relayed by traditional knowledge and Western science

Indigenous community members along the Slave River in Canada have voiced their concerns for the health of ecosystems under pressure from resource extraction, hydroelectric development and global climate change. We present a test case of traditional knowledge and scientific results about the spawning and migration patterns of fish in the Slave River and Delta. This dual knowledge system approach elucidates the broader connectivity of local study regions and can improve monitoring programmes by extending beyond the usual context/confines of the present or recent past, increasing the spatial and temporal range of system information.

The pulse of driftwood export from a very large forested river basin over multiple time scales, Slave River, Canada

AbstractThis study presents a case study of large wood transport on the great Slave River in northern Canada with the objective to better understand the processes of and variability in pulsed wood fluxes from large forested catchments. We use a varied approach, integrating field characterization of wood, historical anecdotes, repeat aerial imagery of stored wood, and time‐lapse imagery of moving wood, for a robust analysis and synthesis of processes behind pulsed wood flux, from yearly uncongested export to rare congested wood floods. Repeat monitoring of known sites of temporary storage with new or historic imagery proved to be a very useful tool for constraining wood flux histories. Pulsed wood export on the Slave River is not an artifact of episodic recruitment from major up‐basin disturbances, but rather reflects decadal‐ to half‐century‐scale discharge patterns that redistribute wood recruited from channel migration and bank slumping. We suggest that the multiyear flow history is of paramount importance for estimating wood flux magnitude, followed in declining importance by the yearly sequence of peaks and the magnitude and characteristics of the rising limb of individual floods.

Bridging science and traditional knowledge to assess cumulative impacts of stressors on ecosystem health

Cumulative environmental impacts driven by anthropogenic stressors lead to disproportionate effects on indigenous communities that are reliant on land and water resources. Understanding and counteracting these effects requires knowledge from multiple sources. Yet the combined use of Traditional Knowledge (TK) and Scientific Knowledge (SK) has both technical and philosophical hurdles to overcome, and suffers from inherently imbalanced power dynamics that can disfavour the very communities it intends to benefit. In this article, we present a ‘two-eyed seeing’ approach for co-producing and blending knowledge about ecosystem health by using an adapted Bayesian Belief Network for the Slave River and Delta region in Canada's Northwest Territories. We highlight how bridging TK and SK with a combination of field data, interview transcripts, existing models, and expert judgement can address key questions about ecosystem health when considerable uncertainty exists. SK indicators (e.g., bird counts, mercury in fish, water depth) were graded as moderate, whereas TK indicators (e.g., bird usage, fish aesthetics, changes to water flow) were graded as being poor in comparison to the past. SK indicators were predominantly spatial (i.e., comparing to other locations) while the TK indicators were predominantly temporal (i.e., comparing across time). After being populated by 16 experts (local harvesters, Elders, governmental representatives, and scientists) using both TK and SK, the model output reported low probabilities that the social-ecological system is healthy as it used to be. We argue that it is novel and important to bridge TK and SK to address the challenges of environmental change such as the cumulative impacts of multiple stressors on ecosystems and the services they provide. This study presents a critical social-ecological tool for widening the evidence-base to a more holistic understanding of the system dynamics of multiple environmental stressors in ecosystems and for developing more effective knowledge-inclusive partnerships between indigenous communities, researchers and policy decision-makers. This represents new transformational empirical insights into how wider knowledge discourses can contribute to more effective adaptive co-management governance practices and solutions for the resilience and sustainability of ecosystems in Northern Canada and other parts of the world with strong indigenous land tenure.

Air pockets and water lenses in the ice cover of the Slave River

Communities along the Slave River are concerned about changes in the river ice cover, such as the formation of air pockets and double layers of ice in the ice cover. These anomalies make it challenging to find suitable locations for river ice crossings in winter, necessary for the transportation of goods to and from remote regions and to access hunting, trapping and fishing areas. This study utilized satellite imagery and field observations to document these anomalies of the river ice during the winters from November 2013 to March 2016. Backscatter analysis of the satellite imagery identified low and high density areas of air pockets along the river. Satellite images also revealed cracks and flooding of the river ice, particularly along the downstream reach of the river.