Hydrological and erosion models

Models simulating water and sediment fluxes in more or less complicated landscapes are now many. A recent paper (Merritt et al., 2003) reviews 17 models on the basis of their being physically or empirically based, on inputs and outputs, model structure, runoff, erosion/transport and nutrient modelling, predictive accuracy/limitations. This review, despite its length, barely surfs the now fairly crowded universe of model. It shows some inevitable inaccuracy (e.g. LISEM, differentely from what reported there, describes gully generation, deposition and transport in land) which is certainly due to the continuous rewriting and updating of some of the most recent models. In any case, only models that have been used and possibly examined in their inner details (i.e., their codes) can be properly discussed, criticized and their limits defined. Generally, the manuals that are distributed with the models are not sufficiently informative for such a task.