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Congreso; IV Congreso Argentino de Cuaternario y Geomorfología, XII Congresso da Associação Brasileira de Estudos do Quaternário y II Reunión sobre el Cuaternario de América del Sur; 2009

Institución organizadora:

Asociación Argentina de Cuaternario y Geomorfología, Universidad nacional de La Plata y ABEQUA

Resumen:

The large river basins of South America are important freshwater reservoirs which also harbor an exceptional biodiversity. Immense floodplains develop along most of these rivers being highly productive areas of the catchments. The Paraná is the second largest fluvial hydrosystem of South America, draining 15 % of the continental surface and discharging to the sea annually about 630 km3 of freshwater. The fringing floodplain of the Middle Paraná River is ca. 20,000 km2 in area, being connected with several important tributary floodplains as well as large wetlands. The floodplain lakes of the Middle Paraná River alluvial landscape vary considerably in shape and size. These basins range in shape from circular to irregular and in area from less 0.01 km2 to greater than 15 km2, showing the 78.7 % of lakes a range between 0.01 and 0.40 km2. Lakes with elongated-channel shaped basins are generally the predominant class of lakes on the floodplain. River dynamics through lateral scouring and filling processes together with long-term channel changes at the riverscape scale, generates and changes the lentic water bodies giving rise to a diverse morphology and hydrologic behaviour. Thus, in lake-rich terrain as river floodplains, the lakes are essentially the short- and long-term residual landforms of the river dynamics. The purpose of this paper is to summarize a basin-wide survey of lake morphometries and to examine the relationships with the main channel and floodplain evolution, as well as with the hydrological connectivity.