Large-scale modelling of channel flow and floodplain inundation dynamics and its application to the Pantanal (Brazil)

摘要

For large-scale sites, difficulties for applying coupled one-dimensional (1D)/2D models for simulating floodplain inundationnmay be encountered related to data scarcity, complexity for establishing channel–floodplain connections, computationalncost, long duration of floods and the need to represent precipitation and evapotranspiration processes. This paper presentsna hydrologic simulation system, named SIRIPLAN, developed to accomplish this aim. This system is composed by a 1Dnhydrodynamic model coupled to a 2D raster-based model, and by two modules to compute the vertical water balance overnfloodplain and the water exchanges between channel and floodplain. Results are presented for the Upper Paraguay River Basinn(UPRB), including the Pantanal, one of the world’s largest wetlands. A total of 3965 km of river channels and 140 000 km2nofnfloodplains are simulated for a period of 11 years. Comparison of observed and calculated hydrographs at 15 gauging stationsnshowed that the model was capable to simulate distinct, complex flow regimes along main channels, including channel-nfloodplain interactions. The proposed system was also able to reproduce the Pantanal seasonal flood pulse, with estimatedninundated areas ranging from 35 000 km2n(dry period) to more than 120 000 km2n(wet period). Floodplain inundation mapsnobtained with SIRIPLAN were consistent with previous knowledge of Pantanal dynamics, but comparison with inundationnextent provided by a previous satellite-based study indicates that permanently flooded areas may have been underestimated.nThe results obtained are promising, and further work will focus on improving vertical processes representation over floodplainsnand analysing model sensitivity to floodplain parameters, time step and precipitation estimates uncertainty. Copyright  2010nJohn Wiley & Sons, Ltd.