  We consider the late-time tailing in a tracer test performed with a
push-drift methodology (i.e., quasi-radial injection followed by drift under
natural gradient). Numerical simulations of such tests are performed on 1000
multi-Gaussian 2D log-hydraulic conductivity field realizations of varying
heterogeneity, each under eight distinct mean flow directions. The ensemble
pdfs of solute return times are found to exhibit power law tails for each
considered variance of the log-hydraulic conductivity field, $\sigma^2_{\ln
K}$. The tail exponent is found to relate straightforwardly to $\sigma^2_{\ln
K}$ and, within the parameter space we explored, to be independent of
push-phase pumping rate and pumping duration. We conjecture that individual
push-drift tracer tests in wells with screened intervals much greater than the
vertical correlation length of the aquifer will exhibit quasi-ergodicity and
that their tail exponent may be used to infer $\sigma^2_{\ln K}$. We calibrate
a predictive relationship of this sort from our Monte Carlo study, and apply it
to data from a push-drift test performed at a site of approximately known
heterogeneity---closely matching the existing best estimate of heterogeneity.
