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Descripción
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| Mediterranean countries are known by their pleasant and healthy climate and therefore humans have habited them since the early beginnings of their civilization. Mediterranean landscapes have been traditionally densely populated, overgrazed and intensively farmed. More recently, industrial developments have taken place in certain regions, and touristic developments have transformed sea shores into continuous urbanized area These historical land-uses have created high pressures on river ecosystems and fluvial resources, specially by means of a high water demand aggravated by irregularity and uncertainity of precipitation regime, natural water scarcity and high evapotranspiration rates, all of them characterizing Mediterranean climatic conditions. Although the Mediterranean rivers have a long history of man's interaction with the natural environment, it is clear that the major alterations of rivers have taken place in the last fifty years. In Spain, the intense use of water resources and river modifications starts in the 50´s, with a policy of large dams construction for irrigation. Together with flow regulation, many agricultural land reclamation and channelization works were implemented during the following decades, causing severe hydromorphological impacts on rivers, together with non-point source pollution. In addition to these alterations of rivers linked to agriculture, industrial impacts started to be significant during the 70´s, with severe pollution examples along many fluvial reaches in parallel with the growth of cities. At the end of the 80´s a new river pressure arised from construction of many high roads and transport services, occupying fluvial areas in many valleys. Finally, during the 90´s and until now, an intensive urbanization strategy has deteriorated the majority of river landscapes, with some urban river reaches dramatically transformed or piped. 2 The most important pressures that affect Mediterranean rivers come from agriculture and urban development, including in this latter industrial, commercial and transport facilities. These pressures produce many different impacts whose effects are cumulative in time and space, affecting a wide variety of environmental attributes of river systems. Meanwhile agriculture requires a high water consumption and river flow regulation, and creates severe problems with agricultural pollutants, its land use is more reversible than that of urbanization. Urban developments often occupy floodplain areas and imply not only river pollution but lost of river dynamics and natural functioning, being much more permanent and difficult to remove than agricultural activities. In this paper, the use of fluvial resources and its impact on river ecosystems are analysed according to these pressures, reviewing previous works (González del Tánago & García de Jalón, 2007). Water, sediments, fish, riparian wood and power are probably the fluvial resources more valuable for economic activities, all of them affected by these pressures. | |
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Internacional
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Si |
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Nombre congreso
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Jornada Técnica “WATER SCARCITY & MANAGEMENT UNDER MEDITERRANEAN CLIMATE” |
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Entidad organizadora
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”. ICRA (Instituto Catalá Recerca delÀigua) |
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Nacionalidad Entidad
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ESPAÑA |
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Lugar/Ciudad de impartición
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Girona |
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Fecha inicio
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24/11/2008 |
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Fecha fin
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25/11/2008 |