Assessment of Uncertainty Associated with the Extent of Simulation Processes from Point to Catchment: Application to 1D Pesticide Leaching Models

Mathematical models have been used to assess the fate and transport of pesticides at different scales over the past 25 years and now are increasingly used to investigate and assess virtually every type of pesticide problem (Cheng, 1990; van der Werf, 1996; Klepper et al., 1999; Bobba et al., 2000; Brawley et al., 2000; Vanclooster et al., 2000). These models are useful tools for determining pesticide concentrations in the environment and for helping in environment management. Given future input scenarios, it is claimed that the model can predict pesticide behavior. Obviously, such model prediction is uncertain because it is uncertain whether the model structure is valid, mathematical equations describing each process are correct, the model parameters are correctly chosen, and the input data are error free (Lei and Schilling, 1996).