Correlation Between Stream Discharge and Dissolved Oxygen Concentration at Salish Creek, Vancouver Pacific Spirit Park

Abstract

Stream discharge and dissolved oxygen (DO) concentration are important abiotic factors for salmon. The existence of a linear correlation between these two abiotic factors could bear significance to the salmon ecosystem. In this study, we examined the existence of a linear correlation, or the lack thereof, between these two variables with our alternative hypothesis being that there is a linear correlation between the two variables. To do this, we measured DO concentration and stream discharge at 3 ripple water sites and 3 still water sites from upper Salish Creek. Stream discharge was calculated using the wetted depth, the wetted channel width, and the stream velocity. The correlation coefficient was found to be -0.516, suggesting a moderate negative trend. Using the Pearson’s Product Moment Correlation test, P-value was found to be 0.296, and at a significance level of 0.05, P-value > 0.05. Thus, we failed to reject the null hypothesis. This may be due to the increased amount of organic matter leading to greater biochemical oxygen demand (BOD) caused by the mixing of the water column at ripple water sites, and a greater BOD  would result in a lower DO. We conclude that there was not enough statistical evidence to indicate that there is a linear correlation between stream discharge and DO concentration.