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Fig. 5. Measured breakthrough curve (BTC) with continuous time random walk/advection-dispersion equation (CTRW/ADE) fits for an unsaturated Oakley sand at a volumetric water content 
= 0.27; (dimensionless) flux-averaged concentration j vs. pore volumes. Upper figure shows the complete BTC; lower figure focuses on the region identified by the bold-framed rectangle in the upper figure. Note the difference in scale units between the figures. Column length equals 30 cm. Velocity v = 1.03 cm h–1 (After Nielsen and Biggar's [1962], Fig. 10, filled circles). Dashed line: best ADE model fit. Solid line: best CTRW fit.
