Search

This article provides a comprehensive overview of ice-jam flood forecasting methodologies applicable to rivers during freezing. It emphasizes the importance of understanding river ice processes and fluvial geomorphology for developing a freeze-up ice-jam flood forecasting system. The article showcases a stochastic modelling approach, which involves simulating a deterministic river ice model multiple times with varying parameters and boundary conditions. This approach has been applied to the Exploits River at Badger in Newfoundland, Canada, a river that has experienced several freeze-up ice-jam floods. The forecasting involves two approaches: predicting the extent of the ice cover during river freezing and using an ensemble method to determine backwater flood level elevations. Other examples of current ice-jam flood forecasting systems for the Kokemäenjoki River (Pori, Finland), Saint John River (Edmundston, NB, Canada), and Churchill River (Mud Lake, NL, Canada) that are operational are also presented. The text provides a detailed explanation of the processes involved in river freeze-up and ice-jam formation, as well as the methodologies used for freeze-up ice-jam flood forecasting. Ice-jam flood forecasting systems used for freeze-up were compared to those employed for spring breakup. Spring breakup and freeze-up ice-jam flood forecasting systems differ in their driving factors and methodologies. Spring breakup, driven by snowmelt runoff, typically relies on deterministic and probabilistic approaches to predict peak flows. Freeze-up, driven by cold temperatures, focuses on the complex interactions between atmospheric conditions, river flow, and ice dynamics. Both systems require air temperature forecasts, but snowpack data are more crucial for spring breakup forecasting. To account for uncertainty, both approaches may employ ensemble forecasting techniques, generating multiple forecasts using slightly different initial conditions or model parameters. The objective of this review is to provide an overview of the current state-of-the-art in ice-jam flood forecasting systems and to identify gaps and areas for improvement in existing ice-jam flood forecasting approaches, with a focus on enhancing their accuracy, reliability, and decision-making potential. In conclusion, an effective freeze-up ice-jam flood forecasting system requires real-time data collection and analysis, historical data analysis, ice jam modeling, user interface design, alert systems, and integration with other relevant systems. This combination allows operators to better understand ice jam behavior and make informed decisions about potential risks or mitigation measures to protect people and property along rivers. The key findings of this review are as follows: (i) Ice-jam flood forecasting systems are often based on simple, empirical models that rely heavily on historical data and limited real-time monitoring information. (ii) There is a need for more sophisticated modeling techniques that can better capture the complex interactions between ice cover, water levels, and channel geometry. (iii) Combining data from multiple sources such as satellite imagery, ground-based sensors, numerical models, and machine learning algorithms can significantly improve the accuracy and reliability of ice-jam flood forecasts. (iv) Effective decision-support tools are crucial for integrating ice-jam flood forecasts into emergency response and mitigation strategies. [ABSTRACT FROM AUTHOR]

Collecting data on the dynamic breakup of a river's ice cover is a notoriously difficult task. However, such data are necessary to reconstruct the events leading to the formation of ice jams and calibrate numerical ice jam models. Photogrammetry using images from remotely piloted aircraft (RPA) is a cost-effective and rapid technique to produce large-scale orthomosaics and digital elevation maps (DEMs) of an ice jam. Herein, we apply RPA photogrammetry to document an ice jam that formed on a river in southern Quebec in the winter of 2022. Composite orthomosaics of the 2-km ice jam provided evidence of overbanking flow, hinge cracks near the banks and lengthy longitudinal stress cracks in the ice jam caused by sagging as the flow abated. DEMs helped identify zones where the ice rubble was grounded to the bed, thus allowing ice jam thickness estimates to be made in these locations. The datasets were then used to calibrate a one-dimensional numerical model of the ice jam. The model will be used in subsequent work to assess the risk of ice interacting with the superstructure of a low-level bridge in the reach and assess the likelihood of ice jam flooding of nearby residences. [ABSTRACT FROM AUTHOR]

The prairie waterbodies face a future of warming temperatures and growing water demands. There are increasing concerns about how water quality will be affected. Water quality models are an effective tool for examining scenarios of future conditions that cannot be measured directly. This study combined WASP and CE-QUAL-W2 to investigate the potential impacts of changing flow management and climate change in the Canadian Prairies. The two models were loosely coupled to simulate a strategically managed river-reservoir network. Climate data from the Coupled Model Intercomparison Project Phase 6 (CMIP6) model ensemble were used to create future climate scenarios. Interbasin water transfers were then simulated through the coupled models to determine if any negative impacts from climate change on water quality could be offset through flow management. Climate change impacts in the river stretch were minimised due to the rapid flow travel time along the channel. The interbasin water transfers had a greater influence on water quality concentrations in the river. This result was limited by the uncertain hydro-climatic future of the contributing watershed. Climate change impacts in the downstream reservoir were far more apparent. Evaporative losses increased approximately 150% from the base model by the 2080–2100 period. Chlorophyll-a concentrations increased an average of 53% in this same period based on monthly mean percentage change. Reservoir water quality was improved after adding the interbasin water transfers. Results indicated that flow management would have a positive impact on water quality in the reservoir in the face of future climate change. [ABSTRACT FROM AUTHOR]

The main difference between an open-water (regular) flood and an ice jam flood is that it is normally the whole river length that is overtopped whereas an ice jam flood is localized to where the jam is located. Comparatively, the regular flood analysis can use the value of the extreme discharge as the main input parameter for a long river section, an ice jam flood needs to account for the probability of jams of various lengths and intensities occurring at specific locations under significantly variable discharges while having several mechanical ice parameters to be considered. Through the case study of the Chaudière River, the methodology presented in this paper demonstrates how to statistically characterize four significant inputs (jam location, jam length, jam properties and river discharge during jam event) into the widely used numerical river water model (HEC-RAS) and how Monte-Carlo simulations are generated to estimate probable ice jam floods along a whole river reach. The purpose of this article is to propose a robust methodology through a case study and asses the sensitivity that historical and mechanical parameters have as to why specific locations along the reach have higher 1:100 AEP ice-induced water levels as to 1:100 AEP open-water levels. [ABSTRACT FROM AUTHOR]

Spring floods have become less frequent along the Slave River and Slave River Delta. As a result, prolonged dry periods have occurred leading to an influx of invasive vegetation more tolerant to dry conditions (e.g., willows). Ice cover breakup and ice jamming can be important mechanisms in river flooding. A clear understanding of spatial and temporal patterns of the spring ice cover breakup along the Slave River could identify possible causes of reduced flood magnitude and frequency in the Slave River Delta. Few attempts have been made to examine the patterns of ice cover breakup along this river. A geospatial model has been introduced in this study to pinpoint the most likely areas of breakup initiation and persistent ice and ice cover at the end of the breakup period along the river. Relatively narrow river sections are responsible for initiation of breakup and relatively wide sections of the river have a strong predisposition for persistent ice along the Slave River. Daily time series of MODIS satellite images acquired from different years were used to examine the spatial and temporal patterns of ice breakup along the Slave River. In addition to geomorphological influence, air temperature and flow conditions also have strong impacts on the spatial and temporal patterns of the ice cover breakup. Key words: Slave River, breakup, MODIS imagery, geospatial modelling. La frequence des crues printanieres de la riviere des Esclaves et de son delta a diminue. Ainsi, les periodes de secheresse se sont prolongees, ce qui a entraine l'apparition d'une vegetation envahissante et resistante a la secheresse (p. ex. des saules). La debacle et l'embacle sont des mecanismes qui peuvent jouer un role important dans les crues des rivieres. Une bonne comprehension des caracteristiques spatiales et temporelles de la debacle printaniere pourrait permettre de determiner les causes possibles de la diminution de l'amplitude et de la frequence des crues du delta de la riviere des Esclaves. On ne s'est que rarement interesse a etudier les caracteristiques de la debacle le long de cette riviere. Dans la presente etude, un modele geospatial est presente, qui permet d'identifier les zones ou la debacle est le plus susceptible de commencer et celles ou se situe la glace persistante et la couverture de glace a la fin de la periode de debacle le long de la riviere. Les sections relativement etroites du cours d'eau contribuent a amorcer la debacle et les sections relativement larges sont tres propices a la formation de glace persistante le long de la riviere. Une serie chronologique de photos prises quotidiennement par le satellite MODIS et datant de differentes annees a servi a etudier les caracteristiques spatiales et temporelles de la debacle le long de la riviere des Esclaves. En plus du facteur geomorphologique, la temperature de l'air et le debit du cours d'eau influent beaucoup sur les caracteristiques spatiales et temporelles de la debacle. [Traduit par la Redaction] Mots-cles: riviere des Esclaves, debacle, photos MODIS, modelisation geospatiale., Introduction The Slave River is a transboundary river and the Slave River Delta (SRD) is a freshwater ecosystem that is considered to be one of the most productive in the [...]

River ice is an important component to maintain traditional and cultural lifestyles for the peoples along the Slave River in the Northwest Territories. During the winter a stable ice cover provides a vital transportation link to hunting, trapping, and fishing areas along the river. However, little was known about the Slave River ice cover characteristics and behaviour during the freeze-up and ice cover progression period. RADARSAT-2 satellite and time-lapse camera imagery were used in this study to document the different types of ice and understand the mechanisms of ice cover formation progression along the river during the course of winter. Time-lapse images were analyzed to observe the frazil ice generation and patterns of stable ice cover formation of the Slave River near Fort Smith during freeze-up. RADARSAT-2 images acquired from the Slave River Delta areas captured ice cover flooding due to higher river flows in mid-winter. Field surveys along the river provided insights about the ice cover growth in various sections along the river. Air pockets and layers under the ice cover were also detected during the ice surveys. The variation of water flows during the winter has a great impact on the Slave River ice regime. Increases in discharge cause the ice cover to crack or dislodge from the river banks leading to water seeping onto the ice and flooding it, which has implications for muskrat and beaver populations. Key words: Slave River, river ice freeze-up, RADARSAT-2 satellite imagery, time-lapse imagery. La glace de riviere est un element essentiel au maintien des modes de vie traditionnels et culturels des populations vivant le long de la riviere des Esclaves, dans les Territoires du Nord-Ouest. Durant l'hiver, une couverture de glace stable fournit un lien de routier vital menant aux zones de chasse, de trappe et de peche situees le long de la riviere. Cependant, on meconnaissait jusqu'ici les caracteristiques et le comportement de la couverture de glace de la riviere des Esclaves durant la periode d'englacement et de formation de cette couverture. Les images fournies par le satellite RADARSAT-2 et a l'aide d'appareils de prise de vues en accelere ont ete utilisees dans la presente etude pour repertorier les differents types de glace et comprendre les mecanismes de formation et de progression de la couverture de glace le long de la riviere durant toute la periode hivernale. Les images en accelere ont ete analysees et ont permis d'observer l'apparition du frasil et les motifs de formation de la couverture de glace stable sur la riviere des Esclaves a proximite de Fort Smith durant la periode d'englacement. Les images de la region du delta de la riviere des Esclaves provenant du satellite RADARSAT-2 ont mis en evidence un debordement de la couverture de glace au-dela du lit de la riviere en raison des crues se produisant au milieu de l'hiver. Des etudes de terrains effectuees le long de la riviere ont permis de mieux comprendre la croissance de la couverture de glace dans differentes portions du cours d'eau. Des poches et couches d'air situees sous la couverture de glace ont ete egalement reperees au cours des etudes de la glace. Les variations du debit de la riviere pendant l'hiver ont de fortes repercussions sur le regime des glaces de la riviere des Esclaves. En raison des augmentations de debit, la couverture de glace se fissure et se detache des rives, l'eau s'ecoulant alors au-dessus de la glace et recouvrant celle-ci, ce qui a des consequences sur les populations de rat musque et de castor. [Traduit par le Redaction] Mots-cles: riviere des Esclaves, englacement de la riviere, images du satellite RADARSAT-2, images en accelere., Introduction Ice constitutes an important control on the flow regime of a river in winter. Ice along northern rivers can be an important component to the traditional and cultural lifestyles [...]

River ice-jams can create severe flooding along many rivers in cold regions. While ice-jams often form during the spring breakup, the midwinter breakup can cause ice-jamming and flooding. Although many studies have already been focused on forecasting spring ice-jam flooding, studies related to forecasting mid-winter breakup jamming and flooding severity are sparse. The main purpose of this research is to develop a stochastic framework to forecast the severity of mid-winter ice-jam flooding along the transborder (New Brunswick/Maine) Saint John River of North America. A combination of hydrological (MESH) and hydraulic model (RIVICE) simulations was applied to develop the stochastic framework. A mid-winter breakup along the river that occurred in 2018 has been hindcasted as a case study. The result shows that the modelling framework can capture the real-time ice-jam severity. The results of this research will help to improve the capacity of ice-jam flood management in cold regions. [ABSTRACT FROM AUTHOR]

In the spring of 2020, the town of Fort McMurray, which lies on the banks of the Athabasca River, experienced an ice-jam flood event that was the most severe in approximately 60 years. In order to capture the severity of the event, a stochastic modelling approach, previously developed by the author for ice-jam flood forecasting, has been refined for ice-jam flood hazard and risk assessments and ice-jam mitigation feasibility studies, which is the subject of this paper. Scenarios of artificial breakage demonstrate the applicability of the revised modelling framework. [ABSTRACT FROM AUTHOR]

In 2011, Manitoba was stricken by wide-scale flooding causing high flows along the Dauphin River. The unprecedented high discharges at freeze-up created the potential for excessive ice cover thickening and backwater staging exacerbating the flood risk already threatening the communities along the river and upstream-lying Lake St. Martin. Hence, the river ice model RIVICE was implemented to determine flood protection elevations to which existing dikes needed to be raised and extended. Two reaches of the river were modelled separately representing distinct geomorphological characteristics: mildly sloping, more sinuous upper reach and steeper, more channelized lower reach. A global sensitivity analysis based on a Monte Carlo analysis was carried out to determine how differences in these morphological features influence different processes of the ice cover formation. It was found that the sinuous and braided morphology of the upper reach has a marked impact on the sensitivity of the hydraulic roughness and strength parameters. The structure of the ice (porosity) and the discharge were most sensitive to the backwater level outcomes of the steeper and straighter lower reach. Key words: Dauphin River, frazil ice, fluvial morphology, global sensitivity analysis, river ice model, RIVICE. En 2011, le Manitoba a connu des niveaux d'eau eleves dans la riviere Dauphin causant une vaste inondation. Les debits eleves sans precedents lors du gel ont cree un potentiel d'une couverture de glace excessive et une retenue d'eau, augmentant le risque d'inondation mena^ant deja les communautes riveraines et le lac St. Martin en amont. Ainsi, le modele de glaces de rivieres RIVICE a ete utilise pour determiner les elevations auxquelles il faut elever les digues actuelles pour proteger contre les inondations. Deux tron^ons de la riviere ont ete modelises separement, representant des caracteristiques geomorphologiques distinctes: un tron^on superieur a faible pente et plus sinueux et un tron^on inferieur plus abrupt et plus canalise. Une analyse generale de sensibilite basee sur une analyse de Monte Carlo a ete realisee pour determiner la maniere dont les differences dans ces caracteristiques morphologiques influencent les divers processus de formation du couvert de glace. Il a ete decouvert que la morphologie sinueuse et anastomosee du tron^on superieur presente un impact important sur la sensibilite des parametres de rugosite hydraulique et de resistance. La structure de la glace (porosite) et la decharge ont ete les plus sensibles au niveau d'eau retenue sur les tron^ons inferieurs plus abrupts et plus droits. [Traduit par la Redaction] Mots-cles: riviere Dauphin, frasil, morphologie fluviale, analyse globale de sensibilite, modele de glaces de riviere, RIVICE., Introduction Little is known about the geomorphological controls on the formation of ice covers along rivers despite novel sources of information from Geographic Information Systems (GIS) and the latest hydrodynamic [...]