Aspect and soil textural controls on snowmelt runoff on forested Boreal Plain hillslopes

Abstract

Plot studies were conducted on a jack pine forest with sandy soil and aspen forests with sandy and loam soils to examine the controls of slope aspect, soil texture and fall soil moisture content on nearsurface snowmeit runoff and infiltration. It was hypothesized that near-surface runoff would be greater from north-facing slopes on ioam sous with increased faii soil moisture content. Fali sou moisture had no measurable effect on spring snowmeit runoff, infiltration of snowmelt dominated (drainage coefficients 53-100%, median 87%) over near-surface runoff (runoff coefficients 1-65%, median 7%) for most plots. Runoff was related to concrete frost at the minerai sou surface. In contrast to the processes hypothesized, south-facing hiiisiopes with sandy sous generated greater runoff than north-facing slopes or sites with finer-textured soils. These results were due to greater concrete frost development resulting from periodic spring snowmeit and re-freezing in the upper soil. South-facing hiiisiopes with sandy soils featured iower canopy cover, allowing greater solar radiation to reach the snow surface which led to the formation of concrete frost and faster melt rates resulting in near-surface runoff. Where hiiisiopes are connected to receiving surface waters by continuous concrete frost, snowmeit runoff at the watershed scaie may be enhanced.

Hydrometeorological conditions preceding wildfire, and the subsequent burning of a fen watershed in Fort McMurray, Alberta, Canada

“…5) allowed for relatively homogenous overwinter freezing of the upper saturated zone (Price, 1983), which reduced the permeability of the peat (Roulet and Woo, 1986;Quinton et al, 2009) and helped store subsurface water over the winter periods (Price and FitzGibbon, 1987). Ground ice persisted into mid-late May in 2013 and 2014, thus limiting snowmelt water infiltration (Roulet and Woo, 1986) and subsurface water loss to the underlying silty sand and outwash layers (Price and FitzGibbon, 1987). Conversely, the shallow (0-0.2 m) peat had reached above freezing temperatures by the end of snowmelt (mid-April) in 2016, suggesting that low (∼ 0.55 m b.g.s.)…”

“…recreational vehicle exhausts or unextinguished cigarettes) and are harder to predict given that widespread fires occur regardless of the presence of moisture deficits (Amiro et al, 2009). These spring fires therefore possess less obvious antecedent moisture signals, given that they occur post-snowmelt, an important rewetting period for wetlands and forested uplands in the region (Smerdon et al, 2008;Redding and Devito, 2011).…”

Effects of Agricultural Encroachment and Drought on Wetlands and Shallow Lakes in the Boreal Transition Zone of Canada

“…The effect that agriculture may have on nutrient status of shallow open waters will be a complex function of water inputs such as surface and ground water inputs, infiltration rates, drainage patterns, deposition of windblown material and wetland buffer and landscape characteristics. There are substantial differences in hydrologic processes in wetlands associated with naturally forested landscapes versus cleared agricultural systems (van der Kamp et al 2003;Devito et al 2005a;Redding and Devito 2011) and it is likely that this will be reflected in the nutrient status and productivity of wetlands across a gradient of agricultural disturbance. Water in boreal wetlands is likely supplied primarily by summer precipitation and ground water discharge (Redding and Devito 2011); although in years of high precipitation intermittent flows can connect typically isolated basins (Devito et al 2005a, b).…”

“…There are substantial differences in hydrologic processes in wetlands associated with naturally forested landscapes versus cleared agricultural systems (van der Kamp et al 2003;Devito et al 2005a;Redding and Devito 2011) and it is likely that this will be reflected in the nutrient status and productivity of wetlands across a gradient of agricultural disturbance. Water in boreal wetlands is likely supplied primarily by summer precipitation and ground water discharge (Redding and Devito 2011); although in years of high precipitation intermittent flows can connect typically isolated basins (Devito et al 2005a, b). Soil infiltration and storage of moisture appears to reduce surface runoff (Ferone and Devito 2004;Redding and Devito 2011), while forest cover inhibits windblown snow and accumulation of snow drifts which are characteristic of prairie pothole wetlands further south.…”

“…Water in boreal wetlands is likely supplied primarily by summer precipitation and ground water discharge (Redding and Devito 2011); although in years of high precipitation intermittent flows can connect typically isolated basins (Devito et al 2005a, b). Soil infiltration and storage of moisture appears to reduce surface runoff (Ferone and Devito 2004;Redding and Devito 2011), while forest cover inhibits windblown snow and accumulation of snow drifts which are characteristic of prairie pothole wetlands further south. Increasing cultivation near wetlands may lead to increased importance of surface water and nutrient runoff over frozen soils during the spring melt period, but the hydrologic impacts of agriculture are unknown.…”