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The goal of this thesis lies in the identification of possible significant trends in winter temperature and precipitation across Ontario. In this study the trends and variations in several indices of daily winter temperature and precipitation were explored applying least squares regressions and Mann-Kendall test for 13 stations located across Ontario for the period 1939 to 2008. Correlation analysis was also used to detect possible link between winter temperature and winter precipitation variables. Datasets were supplied by Environment Canada. The analysis of the temperature indices indicates a significant upward trend in winter temperature values. Also the analysis of the precipitation indices reveals no significant trend in the winter total precipitation series, decreasing trends in winter snowfall, and increasing trends in winter rainfall. This analysis showed that there has been a significant increase in the number of rainy days, but no significant trend has been detected in the number of snowy days. A downward trend in winter snowfall as a percentage of winter precipitation (S/P), and an upward trend in winter rainfall as a percentage of winter precipitation (R/P) have also been detected. The downward trend in winter S/P is linked to the decreasing trend in the winter snowfall, and the upward trend in R/P is linked to the rising trend in winter rainfall. The trends in inter rainfall and snowfall were found to be correlated with the trend in winter temperatures.

An x-ray computer tomography (CT) scanner technique was employed to directly and nondestructively characterize soil macroporosity in a no-tillage agricultural field, with the intent of developing a relationship for macropore and micropore flow components and transport of non-adsorbed solute through a macroporous soil using the breakthrough curve (BTC) technique. A high resolution volume CT scanner was successfully used to scan 15 undisturbed soil columns (length 200mm; diameter 90mm) from A and B horizons of a no-till plot. Total macroporosity (voids >= 0.54mm) was estimated from 12 depths of each column, and were analysed with regards to vertical and spatial variability and apparent continuity of soil macroporosity. Double-peaked BTCs (concentrations and mass-rate versus time), resulting from miscible displacement experiments were conceptualized as separate BTCs resulting from macropore and micropore flow domains. Using a bi-phasic flow assumption and the conservation of mass and solutes within the columns, a flow separation technique was developed and applied to separate the BTCs into macropore and micropore components. Total macroporosity was estimated to be in the order of 4% and 2% in A and B horizons respectively, constituting 8% and 5% of the total porosity in those horizons. The estimates of macroporosity were found to be log-normally distributed, with a significant decreasing trend with depth at the 95% probability level. The macroporosity estimates correlated very well with bulk density, organic matter content, degree of saturation and saturated hydraulic conductivity. The BTCs were poorly predicted by the transport parameters obtained from the CDE and the method of moments; however, the shapes and other parameters estimated from the BTCs confirmed the presence of relatively higher macropore flow and soil heterogeneity in the B horizon than in the A horizon. The conceptual flow separation relationship indicated that a volume separation factor a plays an important role in determining the concentration of solute reaching the outflow, the mass of chloride ions not being affected as much in the macropore-micropore flow separation. Under saturated conditions, therefore, the presence of macropores can greatly alter outflow concentrations of nonreactive chemicals applied to the surface.