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Numerical simulation of flow and contaminant migration at an extensively monitored landfill
Author(s) -
Sykes J. F.,
Pahwa S. B.,
Lantz R. B.,
Ward D. S.
Publication year - 1982
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr018i006p01687
Subject(s) - piezometer , leachate , plume , hydraulic conductivity , environmental science , soil science , hydrogeology , groundwater flow , groundwater , tracer , streamlines, streaklines, and pathlines , hydrology (agriculture) , vadose zone , aquifer , geology , geotechnical engineering , mechanics , meteorology , soil water , engineering , waste management , physics , nuclear physics
A multidimensional finite‐difference model for groundwater flow and contaminant transport is used to analyze the leachate migration from the Canadian Forces Base Borden landfill. Through the synthesis and interpretation of this contaminant system, the application of the model demonstrates the validation evidence that the model adequately simulates the leachate migration. The validation requires deriving parameters from independent measurements (laboratory and field) for use in the model. Review of previous hydrogeological studies leads to the use of three‐dimensional steady state flow regime of the saturated zone extending some 700 m downgradient of the landfill. Small differences between the measured and predicted piezometric surfaces are attributed to variations in potentiometric measurements, seasonal variations, and extrapolation of laboratory measurements of permeability to the field site. The contaminant migration from the landfill has been extensively monitored. Variation in observed chloride‐ion isopleths interpolated from three sampling periods over a 1‐year period are typical and indicative of significant temporal plume behavior. Three‐dimensional streamlines are used to develop a variable‐width two‐dimensional grid that allows sufficient discretization of the domain to permit the accurate simulation with small values of dispersivities. Sensitivity simulations are performed on the longitudinal and transverse dispersivity, imposed boundary condition potentials, hydraulic conductivity, landfill staging scheme, and sorption (potassium plume). Appropriate values for longitudinal and transverse dispersivities of the order of 5. m and 0.1 m, respectively, were found to be appropriate.