Manitoba Hydro's diversion of the Churchill River at Southern Indian Lake, part of a multi-million dollar hydro-electric development in northern Manitoba, will have extensive economic, social and environmental implications. The impact that the project may have on slush-ice formation in the estuary at the Port of Churchill is one such implication. Previous studies have suggested that reduced flows on the lower Churchill River may alleviate the problem of slush-ice formation which physically terminates the navigation season at Churchill. A reduction in the formation of slush ice would make feasible an average tow week extension of the navigation season. The primary objective of this study was to assess the effect of the Churchill River diversion on the length of the navigation season at the Port of Churchill. A secondary objective was to determine the relationship between the physical variables (slush ice and sedimentation) and the economic variable (insurance coverage) that influence the length of the navigation season. A field trip to Churchill was made in late July, 1973 to collect data. Interviews with hydrologists, ice observers, and National Harbours Board personnel were conducted at this time. In the data analysis, October Churchill River discharges and meteorological data on climatic factors were correlated with dates of Churchill harbour closure due to slush ice for the period 1928-1972......

Slush-ice chilling has been applied to catfish fillets by processors for several years. However, little is known about the effect of this system on fillets’ safety and quality. Salmonella counts were reduced (P≤0.05) between 0.55 - 0.83 log CFU/g by slush ice treatments (0% - 4.5% salt), regardless of salt concentration. Salmonella counts for slush ice treated fillets were less (P≤0.05) than for untreated fillets during refrigerated storage. However, Salmonella reduction was similar (P>0.05) among all treatments after 12 days of storage. Sensory evaluation showed that a 24 h-slush-ice treatment negatively affected (P≤0.05) the texture, drip, and odor of fillets during storage at 2 ± 2°C. Lightness (61.7), hue (80.6), and chroma (10.1) values were similar (P>0.05) between slush-ice fillets and water-chilled fillets. Psychotrophs, coliforms, and E. coli counts (5.1, 1.6 and /g, respectively) were similar (P>0.05) among fillets collected before and after 24 h in slush ice.

Bering Sea storms regularly bring adverse environmental conditions, including large waves and storm surges of up to 4 m, to the west coast of Alaska. These conditions can cause flooding, erosion and other damage that affects marine subsistence activities and infrastructure in the low-lying coastal communities. Storm impacts also include interactions with sea ice in various states: large floes, shore-fast ice, the acceleration of sea-ice formation in frazil or slush state, and the formation of slush-ice berms. Slush-ice berms are accumulations of slush ice that develop under the right wind, water level, water and air temperature, and snow conditions. During a strong wind event, large amounts of slush may be formed and pushed onto the shore, where the slush can accumulate, solidify and protect communities from flooding and erosion. Slush ice berms can also be problematic, restricting access to the coast and presenting other hazards. Residents of Shishmaref and Shaktoolik, communities on the west coast of Alaska, observed the formation of slush-ice berms during storms that occurred in 2007, 2009 and 2011. These formations are important to the communities, and it would be useful to develop the capacity to predict their occurrence. However, scientific work has not been conducted on this phenomenon, with the result that a physical conceptual model describing the formation of slush-ice berms does not exist. In recognition of this need, a project thesis was designed, and had as its main objective to identify and document the environmental and synoptic weather conditions that lead to these types of events, and to develop a descriptive physical conceptual model of slush-ice berm formation. A key to this work was the engagement of traditional knowledge holders and local observers to gather data and information about slush ice and slush-ice berm formation, along with the specific dates when these events took place. This dissertation is organized around three major elements: development of a conceptual model of slush-ice berm formation; presenting the traditional knowledge gathered that led to the development of this model; and documenting the methods and tools used to engage traditional knowledge holders and local observers in this process. In this dissertation, the knowledge from traditional knowledge holders on slush ice formation is presented in the context of feeding into a physical scientific process – specifically, developing a descriptive physical conceptual model of slush-ice berm formation. It is expected that this type of research will contribute to slush-ice berm forecasting which would aid communities’ safety by improving assessment of environmental risk. / Graduate