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Descripción
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| Dimension and characteristics of the riparian corridor of Guadalete river downstream Arcos reservoir have been studied by comparison of 1956, 1984 and 2004 air-photographs series, in order to infer the morphological river trends along the last decades due to flow regulation and land-use changes. Several vegetation and geomorphic units have been distinguished within the riparian corridor, and their evolution together with several morphological variables have been studied in the aforementioned periods. A significant decrease of fluvial territory and the area of bare gravel bars is observed, with an important increase of the mature riparian forest area. Previous Salix formations mixed with Tamarix and Nerium oleander existing along the former gravel-bed dynamic river, have been substituted by vegetated strips dominated by Eucaliptus camaldulensis lining both sides of the actual muddy-bed, fixed channel. The analysis of flow records has shown the hydrological alteration, with special significance on the extreme values and their seasonality. Annual and intra-annual variability have dramatically decreased, with a significant reduction of the ordinary winter floods, meanwhile summer low flows have increased due to irrigation. The application of the ?recruitment box model? within these hydrological alterations allows to understand this Eucaliptus invasion. The frequency reduction of floods with a relatively high sediment transport capacity together with the increase of sediment arrival at the channels from the erodible agricultural fields have resulted in a progressive reduction of the cross-section of the channel and its gradual stabilization, favoring the rapid growth of vegetation. These effects are largely responsible for river channel encroachment and reduction of its flood conveyance contributing to increase recent flooding damages. A watershed scale approach taking into account land use and water resources management is required for restoring the river corridor functioning, aimed to improving the interrelationships between flows, sediments and vegetation coping with actual human water demands. | |
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Internacional
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Si |
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Nombre congreso
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Symposium for European Freshwater Science |
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Tipo de participación
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960 |
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Lugar del congreso
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Girona |
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Revisores
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Si |
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ISBN o ISSN
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DOI
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Fecha inicio congreso
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27/06/2011 |
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Fecha fin congreso
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01/07/2011 |
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Desde la página
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1 |
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Hasta la página
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6 |
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Título de las actas
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