Water Stewardship Information Sources

Resource Name Lateral flow thresholds for aspen forested hillslopes on the Western Boreal Plain, Alberta, Canada
Unique File Number 396
Information Type applied Research
Surface Water A
Aquatic Ecosystem
Groundwater
Groundwater & Surface Water
Management for Natural & Industrial Hazards
Strengths developed quantitative runoff thresholds using irrigation experiments
Limitations applicability of results through space is unclear
Challenges
Outstanding Research Questions
Outstanding Research Questions
Information Subtype boreal hydrology
Organization University of Alberta
Resource Name Redding, TE and Devito, KL. 2008. Lateral flow thresholds for aspen forested hillslopes on the Western Boreal Plain, Alberta, Canada. Hydrological Processes 22: 4287-4300
Resource Purpose To predict the long-term sustainability of water resources on the Boreal Plain region of northern Alberta, it is critical to understand when hillslopes generate runoff and connect with surface waters. The sub-humid climate (P ≤ ET) and deep glacial sediments of this region result in large available soil storage capacity relative to moisture surpluses or deficits, leading to threshold-dependent rainfall-runoff relationships. Rainfall simulation experiments were conducted using large magnitude and high intensity applications to examine the thresholds in precipitation and soil moisture that are necessary to generate lateral flow from hillslope runoff plots representative of Luvisolic soils and an aspen canopy. Two adjacent plots (areas of 2·95 and 3·4 m2) of contrasting antecedent moisture conditions were examined; one had tree root uptake excluded for two months to increase soil moisture content, while the second plot allowed tree uptake over the growing season resulting in drier soils. Vertical flow as drainage and soil moisture storage dominated the water balances of both plots. Greater lateral flow occurred from the plot with higher antecedent moisture content. Results indicate that a minimum of 15–20 mm of rainfall is required to generate lateral flow, and only after the soils have been wetted to a depth of 0·75 m (C-horizon). The depth and intensity of rainfall events that generated runoff > 1 mm have return periods of 25 years or greater and, when combined with the need for wet antecendent conditions, indicate that lateral flow generation on these hillslopes will occur infrequently.
Type of Information article
How does this help decision making?
Program Status complete
NE Coverage boreal plains
Drinking Water
Ecosystem
Fish
Groundwater
Public Safety
SW Quality
SW Quantity y
Link http://onlinelibrary.wiley.com/doi/10.1002/hyp.7038/abstract
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