Effect of vadose zone on the steady-state leakage rates from landfill barrier systems
- Middle East Technical University, Department of Environmental Engineering, Inonu, Bulvari 06531, Ankara (Turkey), E-mail: btarhan@metu.edu.tr
- Queen's University, Geoengineering Centre at Queen's-RMC, Ellis Hall, Kingston, Ontario, K7L 3N6 (Canada), E-mail: kerry@civil.queensu.ca
- Middle East Technical University, Department of Environmental Engineering, Inonu, Bulvari 06531, Ankara (Turkey), E-mail: kunlu@metu.edu.tr
Leakage rates are evaluated for a landfill barrier system having a compacted clay liner (CCL) underlain by a vadose zone of variable thickness. A numerical unsaturated flow model SEEP/W is used to simulate the moisture flow regime and steady-state leakage rates for the cases of unsaturated zones with different soil types and thicknesses. The results of the simulations demonstrate that harmonic mean hydraulic conductivity of coarse textured vadose zones is 3-4 orders of magnitude less than saturated hydraulic conductivity; whereas, the difference is only one order of magnitude for fine textured vadose zones. For both coarse and fine textured vadose zones, the effective hydraulic conductivity of the barrier system and the leakage rate to an underlying aquifer increases with increasing thickness of the vadose zone and ultimately reaches an asymptotic value for a coarse textured vadose zone thickness of about 10 m and a fine textured vadose zone thickness of about 5 m. Therefore, the fine and coarse textured vadose zones thicker than about 5 m and 10 m, respectively, act as an effective part of the barrier systems examined. Although the thickness of vadose zone affects the effective hydraulic conductivity of the overall barrier system, the results demonstrated that the hydraulic conductivity of the CCL is the dominant factor controlling the steady-state leakage rates through barrier systems having single low permeability clay layers.
- OSTI ID:
- 21215955
- Journal Information:
- Waste Management, Vol. 29, Issue 1; Other Information: DOI: 10.1016/j.wasman.2008.02.012; PII: S0956-053X(08)00069-X; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0956-053X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of Clastic Dikes on Vertical Migration of Contaminants in the Vadose Zone at Hanford
Application of a Darcian Approach to Estimate Liquid Flux in a Deep Vadose Zone