Electronic Journal of Differential Equations, Vol. 2007(2007), No. 147, pp. 1-30. Title: Multiscale elliptic-parabolic systems for flow and transport Authors: Malgorzata Peszynska (Oregon State Univ., Corvallis, OR, USA) Ralph E. Showalter (Oregon State Univ., Corvallis, OR, USA) Abstract: An upscaled elliptic-parabolic system of partial differential equations describing the multiscale flow of a single-phase incompressible fluid and transport of a dissolved chemical by advection and diffusion through a heterogeneous porous medium is developed without the usual assumptions of scale separation. After a review of homogenization results for the traditional low contrast and the $\epsilon^2$-scaled high contrast cases, the new discrete upscaled model based on local affine approximations is constructed. The resulting model is mass conserving and contains the effects of local advective transport as well as diffusion, it includes non-Fickian models of dispersion and works over a broad range of contrast cases. Submitted October 05, 2007. Published November 05, 2007. Math Subject Classifications: 76S05, 35B27, 74Q15, 35R10. Key Words: Upscaled porous media; double porosity models; multiscale flow and transport; nonlocal dispersion