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As the climate changes, ice characteristics and river-ice processes are altered, sometimes in unexpected ways. A warmer climate will obviously result in less ice globally, and in a general northward shift in the limits of seasonal river-ice occurrence. However, in several watersheds, the frequency of midwinter breakup events and the intensity of breakup ice jams may also change. In addition, climate change will alter other river-ice processes such as ice formation, freeze-up jams, and hanging dams. This is of concern during the design and construction of infrastructure as well as during the planning and implementation of flood-damage-reduction measures in and along rivers with seasonal ice covers. Changes in river-ice regimes will also alter the ecology of many lotic systems. The paper reviews the potential effects of a changing climate on river-ice properties and processes, and provides a discussion of future outcomes and their significance, as well as a suggested direction for future cold-regions river research. [ABSTRACT FROM AUTHOR]

Major ice jam floods occurred along the Saint John River at Perth-Andover, New Brunswick, in 1976, 1987, 1993, 2009, and 2012. These floods have been devastating and resulted in relocation or demolition of many buildings in affected areas of the community. The purpose of this paper is to review ice processes along the Saint John River from Grand Falls to Beechwood Dam and their relevance to the ice-related problems that have occurred in Perth-Andover. The HEC-RAS program was chosen for ice jam flood stage computations, and cross-sectional, roughness and flow information entered to create a model of the study reach. The model was calibrated using field data obtained on 31 March 2000 along an ice jam in the Perth-Andover area. Model applications resulted in stage-discharge relationships for ice jams of different lengths and locations within the study stretch (Beechwood Dam to Grand Falls). These relationships indicate that ice jams can cause flooding at Perth-Andover, even with moderate spring breakup flows. The variation of ice jamming potential along the study stretch, and its relation to reservoir bathymetry and slope, are discussed. The increase in the number and severity of ice jam floods that have affected Perth-Andover may have resulted from changes in infrastructure and climate that have occurred since the 1950s. Local ice problems are likely to be aggravated over the next few decades but tempered in the longer term if the climate continues to change according to current projections. Key words: river ice, climate, ice jams, modelling, stage frequency, Perth-Andover. Les embacles ont provoque d'importantes crues le long de la riviere Saint-Jean, a Perth-Andover au NouveauBrunswick, en 1976, 1987, 1993, 2009 et 2012. Ces crues ont ete devastatrices et ont entraine le deplacement ou la demolition de nombreux batiments dans les secteurs touches de cette localite. L'objectif du present article est d'etudier les comportements de la glace presente le long de la riviere Saint-Jean, de Grand-Sault au barrage de Beechwood, et leur lien avec les problemes causes par la glace a Perth-Andover Dam. Le logiciel HEC-RAS a ete choisi pour calculer les niveaux des crues causees par des embacles et on y a entre des donnees relatives a des sections transversales de la riviere, a la rugosite et au debit, afin de modeliser la zone etudiee. Le modele cree a ete ajuste a l'aide de donnees collectees sur le terrain le 31 mars 2000, le long d'un embacle situe dans le secteur de Perth-Andover. Les mises en application du modele ont mis en evidence des relations entre la hauteur d'eau et le debit au niveau du barrage pour des embacles de differentes longueurs et situes a differents endroits de la zone etudiee (entre le barrage de Beechwood Dam et Grand-Sault). Ces relations montrent que les embacles peuvent entrainer des crues a Perth-Andover, meme en presence de debits printaniers moderes en periode de debacle. On analyse ici la variation du risque de formation d'embacles dans la zone etudiee et sa relation avec la profondeur et la pente au niveau du reservoir. L'augmentation du nombre et de l'amplitude des crues causees par les embacles et survenues a Perth-Andover pourrait avoir ete causee par les modifications des infrastructures et du climat qui se sont produits depuis les annees 1950s. Les problemes locaux engendres par la glace risquent de s'aggraver au cours des prochaines decennies tout en etant attenues a long terme si le climat continue a changer selon les projections actuelles. [Traduit par la Redaction] Mots-cles: glace de riviere, climat, embacles, modelisation, periodicite des crues, Perth-Andover., Introduction Flooding along upper and middle stretches of the Saint John River is a common occurrence and ice jamming has been a major cause of several past floods. Ice-related floods [...]

Greater opportunity now exists compared to 35 years ago for civil engineers to apply river ice knowledge to practical problems of planning, designing, and operating hydro-power facilities, water intakes, bridges, and other infrastructure along ice-covered rivers. This is due to major advancements made during this period in understanding the physical processes of river ice formation, growth and breakup, in developing instrumentation for acquisition of information on winter environments, and in developing numerical modelling tools. An increasing number of journal articles, as well as papers presented at the river ice workshops of the CGU Committee on River Ice Processes and the Environment (CRIPE) and the ice symposia of the International Association for Hydro-Environment Engineering and Research (IAHR) attest to the advancement in river ice science and engineering knowledge that has occurred during the past 35 years. This paper reviews the developments in river ice science and engineering from a Canadian perspective and briefly discusses future directions. Key words: river ice, river ice processes, instrumentation, modelling, mitigation, civil engineering. Les ingenieurs civils ont plus souvent l'occasion aujourd'hui qu'il y a 35 ans d'appliquer les connaissances disponibles sur la glace de riviere a la resolution des problemes pratiques de planification, de conception et de fonctionnement lies aux installations hydroelectriques, ouvrages de prise d'eau, ponts et autres infrastructures installees le long des rivieres couvertes de glace. Cela est du aux avancees majeures realisees au cours des 35 dernieres annees dans la comprehension des phenomenes physiques de la formation, du developpement et de la rupture de la glace de riviere, dans la conception d'instruments d'acquisition de donnees sur les conditions hivernales et dans le developpement d'outils de modelisation numerique. De plus en plus d'articles de revues scientifiques et de publications, presentes dans le cadre des ateliers du CRIPE (Committee on River Ice Processes and the Environment) organises par l'Union Geophysique Canadienne (UGC) et lors des symposiums sur la glace de l'IAHR (International Association for Hydro-Environment Engineering and Research), attestent les progres des connaissances, accomplis ces 35 dernieres annees, en science et en ingenierie specialisees dans la glace de riviere. Le present article decrit ces avancees du point de vue canadien et traite brievement des perspectives d'avenir dans ce domaine. [Traduit par la Redaction] Mots-cles: glace de riviere, processus lies a la glace de riviere, instruments, modelisation, mesures d'attenuation, ingenierie civile., Introduction During the past 35 years, great strides have been made in river ice hydraulics. Canadian engineers and scientists have been forefront in developing a greater understanding of river ice [...]

Presents a study that developed a two-dimensional axisymmetric finite element model for creep deformation in floating ice. Review of literature on the behavior of ice under short- and long-term loading conditions; Details of the application and validation of the model; Results and implications.

River ice is present in nearly all Canadian rivers, for periods ranging from days to many months. Whether moving or stationary, it interacts with the river flow in various ways, resulting in multiple impacts on the economy and ecosystem, and posing a major flood threat to riverside communities. In the past 4 years, Canadian research and development efforts have been directed at a variety of problems. A strong focus on ice breakup and ice jam processes resulted in improved understanding of the salient geomorphological and hydroclimatic factors, enhanced modelling and prediction capabilities, and development of techniques for in situ measurement of ice jam properties. Key contributions in the area of ecological impacts of river ice and ice jams have led not only to solid advances in knowledge, but also to an appreciation of the vast scope of this subject and its numerous links to environmental science. A closely related topic, the flux of suspended sediment in ice-laden rivers was studied for the first time, in order to delineate the effects of the ice on sediment and associated contaminant loads. In response to growing concern about climate change and variability, several studies addressed implications to ice regime, and thence, to ecology and economy. Although not fully explored, the potential impacts appear to be numerous and significant, owing to the highsensitivity of river ice processes to climatic factors. In the foreseeable future, research is likely to continue along the above noted lines, although an increased emphasis on climatic and ecological aspects is probable. Insights gained on the mechanisms of breakup and jamming may lead to increased modelling applications and testing of theoretical concepts. [ABSTRACT FROM AUTHOR]