Scaling laws for the macrodispersivity of ow through porous media are derived from the assumed scaling properties of geological heterogeneity. If is the exponent characterizing uid scaling and is the exponent which characterizes geological heterogeneity, then a simple scaling relation is = maxfa2 ; 1 a2 g. Typically, 0 < < 1, and 12 < < 1, leading to an anomalous, or scale dependent, di usion p...