The role of previously glaciated landscapes in spatiotemporal variability of streamflow in snow-dominated watersheds: British Columbia, Canada

Abstract

Study regionTwenty-six glaciated basins on the Interior Plateau (56° N, 125° W) in British Columbia, Canada. Study focusLandscape and streamflow characteristics in glaciated basins show high spatiotemporal variability, while the linkages among runoff characteristics, landscapes, and glacial history remain unclear. We compiled a 10-year dataset of daily climate and streamflow observations, and 54 landscape attributes for 26 glaciated basins to explore the relationship between landscape, streamflow and glacial history. A Hierarchical Multiple Factor Analysis was performed to analyze landscapes. The hydrological signatures were selected to describe streamflow characteristics. A correlation analysis and machine learning models were used to explore the relationships between the glacial legacy and streamflow variation. New hydrological insights for the region(1)The landscape is well-structured. The principal components of PC1 and PC2 explain 44% of the total landscape variance, PC1 representing basins with steep, high-relief terrain and alpine glaciation and PC2 representing large, elongated basins with moraine and glacial lakes; (2) The landscape heterogeneity has a key role in accurate streamflow predictions. Most hydrological signatures are controlled by landscape components PC1 and PC2 and can be well predicted by Random Forest using landscape features as inputs. (3) Alpine glaciation results in rapid runoff generation and variable flow regime in mountains, while valley glaciation leads to smooth hydrographs with large baseflows and mild and infrequent extreme flow events in plateaus.