Mechanisms and pathways of lateral flow on aspen‐forested, Luvisolic soils, Western Boreal Plains, Alberta, Canada

Abstract

Abstract:Rainfall simulation experiments by Redding and Devito (2008, Hydrological Processes 23: 4287-4300) on two adjacent plots of contrasting antecedent soil moisture storage on an aspen-forested hillslope on the Boreal Plain showed that lateral flow generation occurred only once large soil storage capacity was saturated combined with a minimum event precipitation of 15-20 mm. This paper extends the results of Redding and Devito (2008, Hydrological Processes 23: 4287-4300) with detailed analysis of pore pressure, soil moisture and tracer data from the rainfall simulation experiments, which is used to identify lateral flow generation mechanisms and flow pathways. Lateral flow was not generated until soils were wet into the fine textured C horizon. Lateral flow occurred dominantly through the clay-rich Bt horizon by way of root channels. Lateral flow during the largest event was dominated by event water, and precipitation intensity was critical in lateral flow generation. Lateral flow was initiated as preferential flow near the soil surface into root channels, followed by development of a perched water table at depth, which also interacted with preferential flow pathways to move water laterally by the transmissivity feedback mechanism. The results indicate that lateral flow generated by rainfall on these hillslopes is uncommon because of the generally high available soil moisture storage capacity and the low probability of rainfall events of sufficient magnitude and intensity.

Controls of streamflow generation in small catchments across the snow–rain transition in the Southern Sierra Nevada, California

“…Thus, subsurface flow was most likely generated from the shallow soil–bedrock interface through preferential pathways, consistent with the mechanism reported by others for the Mediterranean and humid climates (e.g. Tromp‐van Meerveld and McDonnell, ; Fiori et al ., ; Redding and Devito, ; Graham and Lin, ). On the other hand, soil‐pit excavations indicate that soil thickness can vary from less than 50 cm to greater than 150 cm across short distances (Bales et al ., ).…”

Greater abundance of Fagus sylvatica in coniferous flood protection forests due to climate change: impact of modified root densities on infiltration

“…These processes include the varying characteristics of organic layers (Greiffenhagen 2005) and the trees' interception efficiency (Schume et al 2003). The porosity generated by roots may also increase lateral water flow (Redding and Devito 2010) and therefore promote run-off generation (Uchida et al 2005).…”

Where does streamwater come from in low-relief forested watersheds? A dual-isotope approach

“…Lowland areas often exhibit a complex groundwater-surfacewater interaction. Water fluxes between slopes and wetlands are generally small (Devito et al, 2005a;Branfireun and Roulet, 1998), and hillslope-stream connectivity is rare (Redding and Devito, 2010;Ali et al, 2011). These features in lowland forested watersheds appear to be controlled by the complex, and poorly understood, interplay of climate, soils, and geology (Devito et al, 1996(Devito et al, , 2005bSlattery et al, 2006;Sun et al, 2002).…”