Channel scour on temperate alluvial fans in British Columbia

This thesis examined the morphometric controls on channel scour depth on temperate fans in British Columbia, Canada. Scour measurements and morphometric variables were catalogued for 116 fans and used to develop a predictive multivariate equation. Stepwise regression and multimodel inference were used to rank the importance of each morphometric variable and to develop the final predictive models. Watershed area, fan gradient, and fan relief were identified as the most important variables that contributed to channel scour. The predicted scour values explained approximately half of the variance in the observed scour measurements, with the largest deviations observed at higher values. A case study of a debris flow event at Neff Creek demonstrated that intense fan scour can amplify the final deposit volume and cause significant damage on the distal fan. The results of this study can be used to prioritize scour hazard assessments for infrastructure development on fans.