Modelling river discharge at sub-daily time-step: comparison of the performances of the conceptual SWAT model and the process-oriented MARINE model
Résumé
Due to global change, the frequency of intense rainfall events and consequent flash floods are expected to increase in the next decades across the Mediterranean coastal basins. To date, few distributed models are able to simulate hydrological processes at basin-scale at a reasonable time scale to describe these flash events with accurate details. The MARINE model is one of them: it is a process-oriented fully distributed model operating dynamically at the rainfall event time-scale. Both infiltration and saturation excess are represented along with subsurface, overland and channel flows. It does not describe ground-water processes since the model's purpose is to simulate individual flood events during which ground-water processes are considered negligible. The SWAT model is a conceptual semi-distributed model assuming several simplifications in equations that dynamically simulates above- and below-ground processes. It has been recently upgraded to sub-daily time-step calculations. Considering the 1400 km² Têt Mediterranean river basin (southwestern France) as a case-study, the objective of this study was to assess and compare the performances of these two models when simulating the discharge at sub-daily time-step. We first calibrated the two models based on the same input dataset (topography, land-use, soil classes, and meteorological stations’ grid). We then compared the performances of the two models on a number of selected flood events. This ongoing work will contribute to assess the ability of the SWAT model to simulate discharge at sub-daily time-step.
Domaines
Hydrologie
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