Engineering simulation tools for predicting the flow and deposition behavior of debris flows make use of simple rheologic flow laws describing flow resistance. In this contribution we test the possibility to parameterize simple flow models by laboratory investigations. We estimate parameters for the Bingham model from a suite of laboratory experiments in different setups. Material samples were taken from fresh deposits of a muddy debris flow and analyzed over a range of volumetric sediment concentrations and maximum grain sizes. Our results are relatively consistent between most setups. Estimated rheologic parameters show an exponential dependence on volumetric sediment concentration and a systematic variation for mixtures of different maximum grain sizes. Though a rheologic interpretation of bulk flow behavior seems feasible at the laboratory scale, extrapolation of rheologic parameters to prototype flow situation for direct use in numerical simulation tools is not recommended.