Author(s): A. Varrani; M. Nones

Linked Author(s): Arianna Varrani, Michael Nones

Keywords: Multi-scale modelling; River management; Parana River; Nested models; Morphological evolution

Abstract: Using the Parana River as case study, the paper highlights the opportunity to account for different modelling tools in managing riverine environments, depending on the phenomena under study. Given the complexity of river systems, their management requires the consideration of several spatial and temporal dimensions, spanning from the very local (few meters, hours) to the watershed (several hundreds of kilometres, decades), since drivers that can impact the fluvial environment act at many scales. In fact, local alterations of the hydrology could affect the watercourses at a shorter time scale with respect to large morphological impacts due to hydropower reservoirs. At the watershed scale, following appreciable variations of the boundary conditions due to natural (e.g., climate change, floods and droughts, earthquakes and landslides, etc.) and anthropogenic (e.g., water extraction, damming, sediment mining, deforestation, etc.) causes, alluvial rivers may experience important morphological changes of their longitudinal profile and bottom composition, depending on the size of the affected areas, the dimension of the watercourses and their celerity to react and adapt to such alterations. Therefore, when designing appropriate management strategies, water managers should account for many parameters, like the time required to reduce these perturbations to a prescribed fraction and the extension of the affected regions. The adequate management of a river basin consists in coupling different modelling tools, using the concept of nested models, i.e. the outcomes of a coarse model force a more detailed local one, downscaling the zoom to account for all the involved mechanisms at the appropriate scale. To corroborate such assertion, in the present paper the case of the Middle and Lower reaches of the Parana River is described, summarizing the outcomes of different research that simulated their morphological evolution using different approaches, spanning from the 0-D to the 2-D.

DOI: https://doi.org/10.3850/978-981-11-2731-1_038-cd

Year: 2018