HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kelln, C. J. Articles by Qualizza, C. Search for Related Content PubMed Articles by Kelln, C. J. Articles by Qualizza, C. GeoRef GeoRef Citation Agricola Articles by Kelln, C. J. Articles by Qualizza, C. Related Collections Preferential Flow Capillary Barriers Dual Porosity/Permeability Models

ORIGINAL RESEARCH

Fracture-Dominated Subsurface Flow and Transport in a Sloping Reclamation Cover

^a Dep. of Civil and Geologic Engineering, Univ. of Saskatchewan, 57 Campus Dr., Saskatoon, SK, S7N 5A9
^b Syncrude Canada Ltd., Fort McMurray, AB
^* Corresponding author (lee.barbour{at}usask.ca).

Received 13 March 2008.

The successful performance of reclamation soil covers over saline-sodic overburden associated with oil sands mining in northern Alberta, Canada, depends on the dynamics of water and salt migration within these covers. Subsurface flow exerts a significant control on the distribution of soil moisture and salts within reclaimed landscapes. A conceptual model for fracture-dominated lateral subsurface flow and transport in a sloping clay-rich reclamation soil cover over saline-sodic shale overburden was developed based on an interpretation of field observations. This model was then verified through the use of numerical simulations. The conceptual model assumes that lateral subsurface flow is dominated by a preferential flow system and that chemical equilibration between fresh snowmelt water stored in the macropores and higher concentration pore water stored in the soil matrix is nearly instantaneous. Numerical modeling of subsurface flow indicated that the discharge rate and cumulative volume are controlled by the bulk saturated hydraulic conductivity and drainable fracture porosity, respectively. A drainable fracture porosity ranging from 3 to 4% yielded a simulated cumulative discharge similar to measured values. A pseudo-equivalent porous medium transport model was used to simulate the Na⁺ concentration of collected subsurface flow with time. General agreement between measured and simulated values demonstrates that discharge concentrations increase as the depth of perched water diminishes with time and water drains through macropores associated with a matrix of higher solute concentrations lower in the cover profile.

Abbreviations: EPM, equivalent porous medium