Fig. 8. Measured Br^– breakthrough curve (BTC) with continuous time random walk/advection-dispersion equation (CTRW/ADE) fits for a soil column; (dimensionless) flux-averaged concentration j vs. time t. 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. Pressure head h = –15 cm (After Jardine et al.'s [1993] Fig. 2, open triangles). Column length equals 24 cm. Velocity v = 0.354 cm h^–1. Dashed line: best ADE model fit. Solid line: best CTRW fit.