River Networks Attenuate Climate-Induced Flow Trends

River networks are defined by their dendritic or branching architecture; a structure that hierarchically integrates topographically-filtered climate signals. Flow trends in British Columbia and throughout the world are beginning to show hydrological shifts due to climate change and lose of glacial and snowmelt inputs. We hypothesize that through integrating different local signals of climate change, river networks can integrate a diverse climate portfolio. Based on this hypothesis, we predicted that larger catchments would exhibit attenuated flow trends with less variability relative to small catchments. In this study, we identify flow trends over a 37-year period (1970-2007) for 46 sites within the Fraser River basin (~215,500 km²). We found that flow trend variability decreased among sites as catchment area increased with small catchments exhibiting twice to thirty times the range of values to that of large catchments. These findings suggest that river networks are portfolios of climate and that near the outlet flow trends are buffered by asynchrony within the network. Ultimately, watersheds may exhibit an inherent robustness to climate change; a property that stabilizes and benefits stream network inhabitants such as salmon.