The impact of reclamation cover depth on the performance of reclaimed shale overburden at an oil sands mine in Northern Alberta, Canada

Abstract

Multilayer covers are widely accepted reclamation designs in the oil sands region of northern Alberta, Canada, with an ultimate goal of revegetating to species characteristic of predisturbance native plant communities. To determine the optimal depth of reclamation material required to reclaim overburden shale from an oil sands mine, an evaluation was made of the long‐term performance of six reclamation soil cover depths all placed over overburden. The measured soil water contents from different cover thicknesses at South Bison Hills located at the Syncrude Mine site north of Fort McMurray, Alberta, were used to calibrate and validate a dual‐porosity model in HYDRUS‐1D. The calibrated and validated model was then used to evaluate the influence of cover thickness and climatic variability on plant available water for forest growth. The frequency distributions of actual transpiration (Tr) for six cover treatments with a range of leaf area index (LAI) cases were developed. These Tr frequency distributions were then modified by coupling Tr and LAI. The modified frequency distributions for annual Tr for the six simulated cover thickness highlight the strong nonlinearity between the distributions of Tr over a long‐term (60 years) climate cycle in that incremental increases in cover thickness do not produce proportional increases in Tr. The results indicated that, once the cover thickness exceeds 100 cm, there is little incremental increase in the median value of Tr over the 60‐year climate cycle. Copyright © 2014 John Wiley & Sons, Ltd.

Forest water use in the initial stages of reclamation in the Athabasca Oil Sands Region

“…Descriptions of the construction and development of SBH are described by Carey () and Huang et al . (). In summary, SBH is a saline‐sodic clay shale overburden deposit formed into a shallow sloped hill (~60 m elevation) with a broad plateau approximately 14 ha large.…”

“…Field capacity and wilting point of the overlying peat mineral mix were determined to be ~0.46 and ~0.20 m 3 m −3 , respectively, by Huang et al . (). Comparative values for the underlying glacial till soil were also reported by Huang et al .…”

“…Comparative values for the underlying glacial till soil were also reported by Huang et al . () as ~0.36 and ~0.18 m 3 m −3 .…”

Characterizing the spatial variability of the hydraulic conductivity of reclamation soils using air permeability

“…All of these processes can lead to the formation of macropores and fractures, which increase the hydraulic conductivity over time (Meiers et al, 2011). Therefore, accurate knowledge of K s and its spatial variability is important for understanding the hydrology of reclamation covers, and provides key parameters for water balance and solute transport models (Swanson et al, 2003;Huang et al, 2015a).…”

Water table dynamics in a constructed wetland, Fort McMurray, Alberta

“…Under the Government of Alberta Environmental Protection and Enhancement Act, industry is required to reclaim disturbed landscapes to a state of “equivalent land capability” (Daly et al, ; OSWWG, ). Until recently, upland areas have been the focus of reclamation efforts (Brown et al, ; Carey, ; Huang, Barbour, & Carey, ; Kelln, Barbour, & Qualizza, ; Lilles, Purdy, Chang, & Macdonald, ; Rowland et al, ; Sorenson, Quideau, MacKenzie, Landhausser, & Oh, ; Strilesky, Humphreys, & Carey, ). However, considering approximately 90% of wetlands in this region are fen peatlands (Vitt, Halsey, Thormann, & Martin, ) and oil sands extraction activities are removing large portions of these ecosystems from the landscape (Daly et al, ), research has now shifted towards constructing wetlands within reclaimed areas (Daly et al, ; Ketcheson et al, ; Ketcheson et al, ; Nicholls, Carey, Humphreys, Clark, & Drewitt, ; Price et al, ).…”