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The ice conditions in a regulated river will depend on the climatic changes as well as the changes to the hydropower operation strategies in the future. The existing literature shows that very few studies have been carried out to investigate the impact of climate change on the river ice regime, which is important for operation of hydropower in cold climates. In this study, a series of modelling tools have been used to transform the climate change signal in terms of precipitation and air temperature into cross-section based river ice assessment in a basin with a complicated hydropower system. The study is based on the EURO-CORDEX climate change data extracted from a regional climate model driven by a suite of five general circulation models with three representative concentration pathways. Hydrological model simulation results show that the winter and spring flow will be increased, which will have an impact on the river ice conditions towards the middle and end of this century. Reservoirhydropower model simulation shows that the production flows in the winter will be increased in the future. River ice model simulation shows the number of days with freezing water temperature are reduced in the future climate, and correspondingly days with frazil ice are reduced at most of the locations in the study area. The future period with ice cover will also be shortened. The paper also demonstrates a general methodology and procedure to simulate future ice conditions in a regulated river combining multiple models and data sets. [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. [ABSTRACT FROM AUTHOR]

Winter can be a critical time on many rivers, during which ice conditions and a number of environmental factors can lead to rapidly developing and damaging flood events. Also, in northern Canada, rivers are important for both summer (ferry) and winter (ice bridge) transportation; however, during periods of variable ice conditions these transportation links are temporarily interrupted. As a result, northern communities can become isolated for periods of time. With climate warming becoming an increasing concern, it is important to know how elevated temperatures might affect river ice covers so that we can assess the implications for ice jam events, hydropower dam operation, and winter transportation. The Peace River in northern British Columbia and Alberta was used as a case study in this paper to assess the validity of a newly developed, public domain, thermo-hydraulic river ice model, River1D. The Canadian second-generation coupled global climate model (CGCM2) provided an offset for the historical air temperature input, and a future climate analogue for the mid-21st century ice regime was generated. The historical and future climate simulation results indicated significant potential reductions in the duration and extent of ice cover on the Peace River and a longer period over which the river will be impassible by ferry or ice bridge. Specifically, the number of days an ice bridge could be sustained at the Shaftesbury Ferry site was shown to decrease by 60% to 78%. [ABSTRACT FROM AUTHOR]

The passage of river ice during the breakup event can have several effects on bridge structures. Design for ice passage at bridges has largely been empirical, such as the determination of superstructure clearance requirements based on historical stage data. As hydrologic and river ice processes in rivers are modified by climatic change, the use of empirical methods based on past observations and measurements could become less reliable. To advance beyond empiricism, it is necessary to develop rational design criteria based on a thorough understanding of the factors governing the interaction between bridges and ice. This concern applies especially during the breakup event when river flows, velocities, and hydrodynamic forces are usually higher and moving ice is thicker and stronger than during freeze-up. This paper provides guidance on the design of bridges to minimize ice impacts on the structure during the breakup period. [ABSTRACT FROM AUTHOR]