Stream temperature drivers and modelling in headwater catchments on the eastern slopes of the Canadian Rocky Mountains

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MacDonald, Ryan J.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Geography
This thesis quantified processes controlling stream temperature using a field study conducted in headwater catchments on the eastern slopes of the Canadian Rocky Mountains, Alberta. Hydrometeorological data from May-September of 2010 and 2011 were used to describe the drivers of inter-annual stream temperature variation in Star Creek. Inter-annual stream temperature variation was shown to be a function of catchment-scale moisture conditions, driven by seasonal differences in snow accumulation. This field study demonstrated that meteorological and hydrological processes must be considered simultaneously in order to understand stream temperature response to changing environmental conditions in mountain regions. A process-based modelling approach was developed to simulate stream temperature in Star Creek using hydrometeorological and geomorphological data collected during the field study. Modelling results suggest simulations of hydrometeorological variables needed for process-based stream temperature modelling are possible in data-sparse mountain regions using little input data. Model calibration was required because not all variables required for calculating the stream energy budget were measured. However, stream energy budget estimates did compare well with other estimates from field-based studies, providing confidence in the methods applied. A sensitivity analysis demonstrated that simulations were most sensitive to net radiation and parameterization/calibration of surface-subsurface interactions. Results from a climate change study presented in Chapter 4 suggest winter habitat for native salmonids may be reduced as a function of changes in the onset of spring snowmelt. Chapter 4 results suggest that bull trout (Salvelinus confluentus) populations are likely more sensitive to climate change than isolated westslope cutthroat trout (Oncorhynchus clarki lewisii) populations. The climate change study was limited due to boundary conditions remaining constant for all simulations and modelling error. However, these results are supported by an inter-catchment comparison of air temperature, stream temperature, and stream discharge between Lynx, Lyons East and Star creeks. The inter-catchment comparison and climate change results present a conceptual framework of thermal response to climate change that has not been discussed in the literature. Overall, this thesis demonstrates that catchment- and regionally-specific conditions must be considered when assessing the potential impacts of environmental change on stream temperature and native salmonids.
xi, 110 leaves: illustrations (some coloured), maps ; 29 cm
stream temperature variation , Canadian Rocky Mountains , eastern slopes , changing environmental conditions , mountain regions , native salmonids , Water temperature -- Alberta -- Star Creek Watershed -- Measurement , Water temperature -- Alberta -- Star Creek Watershed -- Mathematical models , Mountain watersheds -- Rocky Mountains, Canadian (B.C. and Alta.) , Rivers -- Alberta -- Star Creek -- Measurement , Rivers -- Alberta -- Star Creek -- Mathematical models , Climatic changes -- Environmental aspects -- Alberta -- Star Creek Watershed , Fishes -- Effect of temperature on -- Alberta -- Star Creek Watershed , Salmonidae -- Effect of temperature on -- Alberta -- Star Creek Watershed , Dissertations, Academic