Seasonal and long-term variations in water quality of the Skeena River at Usk, British Columbia

This study analysed data collected from the Skeena River at Usk every 2 weeks between 1984 and 1992 to determine the processes affecting the water quality. In addition, this study assessed the data for the presence of trends (changes in the overall mean of the time-series), modelled the series and forecast future water quality of the river. Hysteresis diagrams were used to determine which processes affect water quality. These diagrams revealed the importance of snowmelt and rainfall peaks on water chemistry. Plots of the water quality variables against time indicated no trends during the study period. Univariate Box-Jenkins techniques were used to model the observed patterns in water quality. These models were then used to project past patterns and relationships into the future (forecasting). These anticipated forecasts may then aid in planning and decision making. The sign test was used to confirm that no trends were present during the study period.