Advertisement

Environmental Earth Sciences

, Volume 62, Issue 1, pp 1–17 | Cite as

Laboratory and numerical modeling of water balance in a layered sloped soil cover with channel flow pathway over mine waste rock

  • Qing SongEmail author
  • Ernest K. Yanful
Original Article

Abstract

Macropores developed in barrier layers in soil covers overlying acid-generating waste rock may produce preferential flow through the barrier layers and compromise cover performance. However, little has been published on the effects of preferential flow on water balance in soil covers. In the current study, an inclined, layered soil cover with a 10-cm-wide sand-filled channel pathway in a silty clay barrier layer was built over reactive waste rock in the laboratory. The channel or preferential flow pathway represented the aggregate of cracks or fissures that may occur in the barrier during compaction and/or climate-induced deterioration. Precipitation, runoff, interflow, percolation, and water content were recorded during the test. A commercial software VADOSE/W was used to simulate the measured water balance and to conduct further sensitivity analysis on the effects of the location of the channel and the saturated hydraulic conductivity of the channel material on water balance. The maximum percolation, 80.1% of the total precipitation, was obtained when the distance between the mid-point of the channel pathway and the highest point on the slope accounted for 71% of the total horizontal length of the soil cover. The modeled percolation increased steadily with an increase in the hydraulic conductivity of the channel material. Percolation was found to be sensitive to the location of the channel and the saturated hydraulic conductivity of the channel material, confirming that proper cover design and construction should aim at minimizing the development of vertical preferential flow in barrier layers. The sum of percolation and interflow was relatively constant when the location of the channel changed along the slope, which may be helpful in locating preferential flow pathways and repairing the barrier.

Keywords

Acid rock drainage Channel flow Laboratory test Soil cover VADOSE/W Water balance 

Notes

Acknowledgments

Funding for this research has been provided by the Natural Sciences and Engineering Research Council of Canada in the form of an Individual Discovery Grant awarded to E.K.Yanful.

Supplementary material

12665_2010_488_MOESM1_ESM.doc (292 kb)
Online Resource Graphs (DOC 292 kb)

References

  1. Adu-Wusu C, Yanful EK (2006) Performance of engineered test covers on acid-generating waste rock at Whistle mine, Ontario. Can Geotech J 43:1–18CrossRefGoogle Scholar
  2. Adu-Wusu C, Yanful EK (2007) Post-closure investigation of engineered test covers on acid-generating waste rock at Whistle Mine, Ontario. Can Geotech J 44:496–506CrossRefGoogle Scholar
  3. Adu-Wusu C, Yanful EK, Lanteigne L, O’Kane M (2007) Prediction of the water balance of two soil cover systems. Geotech Geol Eng 25:215–237CrossRefGoogle Scholar
  4. Akindunni FF, Gillham RW, Nicholson RV (1991) Numerical simulations to investigate moisture-retention characteristics in the design of oxygen-limiting covers for reactive mine tailings. Can Geotech J 28:446–451CrossRefGoogle Scholar
  5. Aubertin M, Bussière B (2001) Discussion of “Water flow through cover soils using modeling and experimental methods”. J Geotech Geoenviron Eng 127:810–811CrossRefGoogle Scholar
  6. Beven K, Germann P (1982) Macropores and water flow in soils. Water Resour Res 18:1311–1325CrossRefGoogle Scholar
  7. Bussière B, Aubertin M, Chapuis RP (2003) The behavior of inclined covers as oxygen barriers. Can Geotech J 40:512–535CrossRefGoogle Scholar
  8. Choo L-P, Yanful EK (2000) Water flow through cover soils using modeling and experimental methods. J Geotech Geoenviron Eng 126:324–334CrossRefGoogle Scholar
  9. Corser P, Cranston M (1991) Observations on long-term performance of composite clay liners and covers. In: Proceedings on geosynthetic design and performance. 6th annual symposium. Vancouver Geotechnical Society, 24 May 1991. VGS, Vancouver, p 16Google Scholar
  10. Daniel DE, Benson CH (1990) Water content-density criteria for compacted soil liners. J Geotech Eng ASCE 116:1811–1830CrossRefGoogle Scholar
  11. Edlefsen NE, Anderson ABC (1943) Thermodynamics of soil moisture. Hilgardia 15:21–298Google Scholar
  12. Egiebor NO, Oni B (2007) Acid rock drainage formation and treatment: a review. Asia Pac J Chem Eng 2:47–62CrossRefGoogle Scholar
  13. Fala O, Molson J, Aubertin M, Bussière B (2005) Numerical modeling of flow and capillary barrier effects in unsaturated waste rock piles. Mine Water Environ 24:172–185CrossRefGoogle Scholar
  14. Fayer MJ (2000) UNSAT-H version 3.0: Unsaturated soil water and heat flow model, theory, user manual, and examples. Pacific Northwest national laboratory, RichlandGoogle Scholar
  15. Fredlund DG, Rahardjo H (1993) Soil mechanics for unsaturated soils. John Wiley & Sons Inc, New YorkGoogle Scholar
  16. Fredlund DG, Xing A (1994) Equations for the soil-water characteristic curve. Can Geotech J 31:521–532CrossRefGoogle Scholar
  17. Fredlund DG, Xing A, Huang S (1994) Predicting the permeability function for unsaturated soils using the soil-water characteristic curve. Can Geotech J 31:533–546CrossRefGoogle Scholar
  18. GEO-SLOPE (2002) SEEP/W for finite element seepage analysis, user’s guide. GEO-SLOPE International Limited, Calgary, Alberta, CanadaGoogle Scholar
  19. GEO-SLOPE (2004) VADOSE/W 2004 User’s guide. GEO-SLOPE International Limited, Calgary, Alberta, CanadaGoogle Scholar
  20. Hill DE, Parlange J-Y (1972) Wetting front instability in layered soils. Soil Sci Soc Am J 36:697–702CrossRefGoogle Scholar
  21. Khire MV, Benson CH, Bosscher PJ (1999) Field data from a capillary barrier and model predictions with UNSAT-H. J Geotech Geoenviron Eng 125:518–528CrossRefGoogle Scholar
  22. Krahn J (2004) Vadose zone modeling with VADOSE/W: An engineering methodology. GEO-SLOPE International Ltd, Calgary, Alberta, CanadaGoogle Scholar
  23. Kung K-JS (1990) Preferential flow in a sandy vadose zone, 2, Mechanisms and implications. Geoderma 46:59–71CrossRefGoogle Scholar
  24. MEND (1991) Acid rock drainage prediction manual. MEND Project 1.16.1b. Coastech Research Inc., VancouverGoogle Scholar
  25. Mitchell JK, Hooper D, Campanella R (1965) Permeability of compacted clay. J Soil Mech Found Div Proc Am Soc Civil Eng 91:41–65Google Scholar
  26. Nadler A, Gamliel A, Peretz I (1999) Practical aspects of salinity effect on TDR-measured water content: A field study. Soil Sci Soc Am J 63:1070–1076CrossRefGoogle Scholar
  27. Nichol C, Smith L, Beckie R (2003) Time domain refelectrometry measurements of water content in coarse waste rock. Can Geotech J 40:137–148CrossRefGoogle Scholar
  28. Nicholson RV, Gillham RW, Cherry JA, Reardon EJ (1989) Reduction of acid generation in mine tailings through the use of moisture-retaining cover layers as oxygen barriers. Can Geotech J 26:1–8CrossRefGoogle Scholar
  29. O’Kane M, Wilson GW, Barbour SL (1998) Instrumentation and monitoring of an engineered soil cover system for mine waste rock. Can Geotech J 35:828–846CrossRefGoogle Scholar
  30. Pham HQ, Fredlund DG, Barbour SL (2005) A study of hysteresis models for soil-water characteristic curves. Can Geotech J 42:1548–1568CrossRefGoogle Scholar
  31. Scanlon BR, Christman M, Reedy RC, Porro I, Simunek J, Flerchinger GN (2002) Intercode comparisons for simulating water balance of surficial sediments in semiarid regions. Water Resour Res 38:591–5916CrossRefGoogle Scholar
  32. Schroeder PR, Aziz NM, Lloyd CM, Zappi PA (1994) The hydrologic evaluation of landfill performance (HELP) model: user’s guide for version 3. EPA/600/R-94/168a, September 1994. U.S. Environmental Protection Agency Office of Research and Development, WashingtonGoogle Scholar
  33. Selker JS, Steenhuis TS, Parlange J-Y (1992) Wetting front instability in homogeneous sandy soils under continuous infiltration. Soil Sci Soc Am J 56:1346–1350CrossRefGoogle Scholar
  34. Simunek J, Sejna M, van Genuchten MTh (1999) The HYDRUS-2D software package for simulating two-dimensional movement of water, heat, and multiple solutes in variably-saturated media, version 2.0. U.S. Salinity Laboratory, USDA, ARS, RiversideGoogle Scholar
  35. Simunek J, van Genuchten MTh, Sejna M (2005) The HYDRUS-1D software package for simulating the movement of water, heat, and multiple solutes in variably saturated media, version 3.0, HYDRUS software series 1. Department of Environmental Sciences, University of California Riverside, RiversideGoogle Scholar
  36. Song Q, Yanful EK (2008) Monitoring and modeling of sand-bentonite cover for ARD mitigation. Water Air Soil Pollut 190:65–85CrossRefGoogle Scholar
  37. Song Q, Yanful EK (2009a) Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer soil cover. J Contam Hydrol (in final review)Google Scholar
  38. Song Q, Yanful EK (2009b) Effect of water addition frequency on oxygen consumption in acid generating waste rock. Accepted for publication in ASCE J Environ Eng (in press)Google Scholar
  39. Suter GW, Luxmoore RJ, Smith ED (1993) Compacted soil barriers at abandoned landfill sites are likely to fail in the long term. J Environ Qual 22:217–226CrossRefGoogle Scholar
  40. Swanson DA, Barbour SL, Wilson GW, O’Kane M (2003) Soil-atmosphere modelling of an engineered soil cover for acid generating mine waste in a humid, alpine climate. Can Geotech J 40:276–292CrossRefGoogle Scholar
  41. Taha MR, Kabir MH (2005) Tropical residual soil as compacted soil liners. Environ Geol 47:375–381CrossRefGoogle Scholar
  42. Taylor G, Spain A, Nefiodovas A, Timms G, Kuznetsov V, Benntt J (2003) Determination of the reasons for deterioration of the Rum Jungle waste rock cover. Australian Center for Mining Environmental Research, BrisbaneGoogle Scholar
  43. Topp GC, Davis JL, Annan AP (1980) Electromagnetic determination of soil water content: Measurements in coaxial transmission lines. Water Resour Res 16:574–582CrossRefGoogle Scholar
  44. van Genuchten MTh (1980) A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 44:892–898CrossRefGoogle Scholar
  45. Walter MT, Kim J-S, Steenhuis TS, Parlange J-Y, Heilig A, Braddock RD, Selker JS, Boll J (2000) Funneled flow mechanisms in a sloping layered soil: laboratory investigation. Water Resour Res 36:841–849CrossRefGoogle Scholar
  46. Wilson GW (1990) Soil evaporative fluxes for geotechnical engineering problems. Ph.D. Thesis, University of Saskatchewan, Saskatoon, CanadaGoogle Scholar
  47. Wilson GW, Fredlund DG, Barbour SL (1994) Coupled soil atmosphere modeling for soil evaporation. Can Geotech J 31:151–161CrossRefGoogle Scholar
  48. Woyshner MR, Yanful EK (1995) Modeling and field measurements of water percolation through an experimental soil cover on mine tailings. Can Geotech J 32:601–609CrossRefGoogle Scholar
  49. Yanful EK, Mousavi SM, Yang M (2003) Modeling and measurement of evaporation in moisture-retaining soil covers. Adv Environ Res 7:783–801CrossRefGoogle Scholar
  50. Yang H, Rahardjo H, Leong EC, Fredlund DG (2004) A study of infiltration on three sand capillary barriers. Can Geotech J 41:629–643CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Geotechnical Research Center, Department of Civil and Environmental EngineeringUniversity of Western OntarioLondonCanada

Personalised recommendations