Many studies have focused on the amount of stemflow in different forests and for different rainfall events, but few studies have focused on how stemflow intensity varies during events or the infiltration of stemflow into the soil. Stemflow may lead to higher water delivery rates at the base of the tree compared with throughfall over the same area and fast and deeper infiltration of this water along roots and other preferential flow pathways. In this study, stemflow amounts and intensities were measured and blue dye experiments were conducted in a mature coniferous forest in coastal British Columbia to examine double funnelling of stemflow. Stemflow accounted for only 1% of precipitation and increased linearly with event total precipitation. Funnelling ratios ranged from less than 1 to almost 20; smaller trees had larger funnelling ratios. Stemflow intensity generally was highest for periods with high‐intensity rainfall later in the event. The maximum stemflow intensities were higher than the maximum precipitation intensities. Dye tracer experiments showed that stemflow infiltrated primarily along roots and was found more frequently at depth than near the soil surface. Lateral flow of stemflow was observed above a dense clay layer for both the throughfall and stemflow experiments. Stemflow appeared to infiltrate deeper (122 cm) than throughfall (85 cm), but this difference was in part a result of site‐specific differences in maximum soil depth. However, the observed high stemflow intensities combined with preferential flow of stemflow may lead to enhanced subsurface stormflow. This suggests that even though stemflow is only a very minor component of the water balance, it may still significantly affect soil moisture, recharge, and runoff generation. Copyright © 2016 John Wiley & Sons, Ltd.

Wildfire can exert considerable influence on many watershed processes, including the partitioning of precipitation by forest canopies. Despite general acknowledgement that canopy interception is reduced following wildfire, effects on net rainfall and snow accumulation have not been quantified. The objectives of this study were to document net rainfall and snow water equivalent (SWE) in burned and unburned (reference) forest stands over a 10-year period to characterise the effects of severe wildfire on net precipitation in the Canadian Rocky Mountains. Differences in summer (June–September) rainfall between burned and reference stands suggest that wildfire reduced rainfall interception by 65%, resulting in a 48% increase in net rainfall from 2006 to 2008. This represented an average annual increase in net rainfall of 122mm (36%) for 10 years after the fire. Similarly, a burned stand had 152mm (78%) higher mean annual peak SWE than a paired reference stand. Collectively, burned stands had 274mm (191–344mm; 51%) more mean annual net precipitation for the first decade after fire. These results suggest that increases in net precipitation are likely following wildfire in subalpine forests and that, owing to the slow growth of these forests, post-fire changes may alter precipitation–runoff relationships for many years.

The complex mechanisms driving runoff dynamics in mountainous watersheds with thick glacial till and fractured bedrock are not well understood. We examined long-and short-term precipitation-runoff relationships and quantified subsurface storage in watersheds on the eastern slopes of Canada's Rocky Mountains to develop a conceptual understanding of runoff generation processes in this region. Fractured permeable bedrock (bedrock storage) and glacial till deposits (soil and till storage) collectively result in large dynamic storage (hydrologically active storage). The transition from multiyear dry to multiyear wet patterns increased specific discharge due to less bedrock storage opportunity but did not influence event-scale rainfall-runoff responses. Rather, event-scale rainfall-runoff responses were governed by snowmelt and soil and till storage capacity. While winter snowfall was an important predictor of annual runoff ratios, storage at the end of the previous fall also influenced runoff ratios. These complex subsurface dynamics and large storage capacities are important for understanding how mountainous watersheds with glacial till deposits may respond to disturbance or climate change.

The Southern Rockies Watershed Project was initiated in 2003 to describe the impacts of severe natural disturbance by wildfire on a broad range of headwaters, larger river basin scale, and downstream water resources (Phase I). This watershed research is unique in that trans-disciplinary linkages between hydrology, biogeochemistry, aquatic ecology, downstream river basin processes, implications for human water use, and economic implications are providing broad insights into wildfire effects on water. A second phase of the research (Phase II) focuses on evaluating the effects of several alternative forest harvesting practices on these same water resource "values". Collectively, this research is providing comprehensive information on watershed function after forest disturbance in Rocky Mountain watersheds. RÉSUMÉLe Projet du bassin hydrographique du Sud des Rocheuses a été lancé en 2003 pour décrire les effets des grandes perturbations naturelles occasionnées par les feux de forêt sur une gamme variée d' eaux d'amont, de bassins versants à grande échelle et de ressources hydriques en aval (Phase 1). Cette étude de bassin versant est unique du fait de ses liens interdisciplinaires entre l'hydrologie, la bio-géochimie, l' écologie aquatique, les processus d' écoulement en aval, les implications relatives à l'usage par l'homme de l' eau et leurs conséquences économiques qui permettent d'avoir une perspective globale sur les effets des feux de forêt sur l' eau. Une deuxième phase du projet (Phase II) porte sur l' évaluation des effets de diverses techniques d' exploitation alternatives sur les « valeurs » de cette même ressource-eau. Dans son ensemble, cette étude apporte une vaste gamme de renseignements sur la fonction des bassins versants après une perturbation forestière dans les bassins versants des Rocheuses.