In this master thesis were characterized two highly porous media and a conduit in sandstone with special focus in the transition region between the laminar and turbulent states. As porous media were used glass beads and coarse sand of similar size, 2 and 1.9 mm respectively; for the laboratory work was used a setup where was possible to control the discharge and was measured the hydraulic head. Laminar flow ceases at Reynolds number of 0.25 in glass beads and 0.21 in coarse sand. The flow follows the same pathway between laminar and transitional, without regard if the velocity was increasing or decreasing. A conduit of 5 mm diameter was drilled in a fragment of sandstone for the experiments. The discharge and head losses through the conduit were measured. It was possible to establish two critical Reynolds values, 365 and 3060, for the state change between laminar to transitional and transitional to turbulent. A hysteretic behavior was observed when the flow switches between laminar and transitional. All the results were modeled using the Conduit Flow Process Mode 2 and compared with the experimental data. For porous media there is not a good agreement between the outputs of the model and the measured data.