Chloride Retention and Infiltration in Upland Root Zone Soil Layer in the Urban Black Creek Watershed, Toronto, Ontario

<p>Winter road salt application has become necessary for road safety and our daily winter commute, however, the environmental damage caused by salting practices continues to be an area of concern. The overarching goal of the research was to see if the chloride retention soil root zone is a possible mechanism for delayed salt release, by assessing the watershed scale retention of chloride over the summer rain season using measured SC. Conducted in Black Creek, Toronto, this research utilized both field and lab sampling to gather SC data for statistical analysis about chloride retention, throughput, spatial, and temporal variability in Black Creek watershed urban upland soil root zones. Using linear regression and ANCOVA modelling, final statistical analysis results suggest a lack of chloride retention on a year-by-year basis, with chloride concentration taking 4 months to reach near baseline levels. Research identified land use type and distance to impervious surface were primary spatial variables contributing to chloride retention in urban root zone soil layer with combined model performance of R²= 0.583. However, high individual site variability made the model not applicable to sites with varying land use and topography. Concluding individual site variability as the greatest factor in chloride concentration of root zone soil layer, with recommendations for future research include increased spatial, site-based resolution.</p>