This project will use the techniques of stereolithography and PIV directly to measure the fluid velocity field in complex, 2D, geologically realistic media with multi-scaled heterogeneities. The resulting velocity fields will be published widely and will provide an invaluable resource for the validation of models of fluid flow in complex geometries for which validation ID presently impossible. Three specific studies will also be undertaken; a) a detailed investigation of the non-linear interaction between matrix and fracture flow, b) a study of the scaling laws in the region of the percolation threshold in the presence of fractal fracture populations and significant matrix permeability and c) an examination of the scaling of the velocity flow field and how this reflects material scaling with a view to identifying potential rules for upscaling of fluid simulations.