In this paper, the head variance and macroscopic dispersion are developed for one- and two-dimensional flows through a semiconfined aquifer with isotropic and anisotropic fractal hydraulic conductivity distribution. It is assumed that the spatial distribution of log hydraulic conductivity can be described as a fractional Brownian motion. The resulting head variance and macrodispersivity tensor, obtained from stochastic fluctuation equations of the steady flow and solute transport, are studied in terms of the hydraulic conductivity process and the leakage in a semiconfined aquifer bounded by a leaky layer above and an impervious stratum below. The impact of the fractal dimension of this process, the leakage factor, and the characteristic length scale on the macrodispersivity is investigated. The results show that the head variance and the transverse macrodispersivity decrease, while the longitudinal macrodispersivity slightly increases with increasing leakage factor. The head variance and longitudinal macrodispersion increase significantly, and the transverse macrodispersion increases slightly as the maximum length scale increases. The increasing fractal dimension generally reduces the head variance and longitudinal macrodispersion and enhances the transverse macrodispersion. The influence of statistical anisotropy of conductivity field on both the head variance and macrodispersivities is also investigated. ¿ 2000 American Geophysical Union