Resumo

MAGNANTE, Leandro; DEGIOVANNI, Susana  e  DOFFO, Nelso. Análisis de los cambios morfológicos y morfodinámicos del arroyo El cano (Córdoba) en la última centuria: factores de control, causas e implicancias ambientales. Rev. Asoc. Geol. Argent. [online]. 2014, vol.71, n.1, pp.56-68. ISSN 0004-4822.

El Cano stream, main tributary of Tegua stream, drains the eastern slope of Sierras de Comenchingones and the adjacent pampean plain, where the pressure of human land use is growing. In this paper its morphological-geomorphological changes in the last century, control factors, causes and environmental consequences, are analyzed. The methodological approach to carry out this study included geological-geomorphological and hydrographic mapping; evolutionary historical analysis of the channel; morphological and sedimentological geoindicators monitoring; and channel zoning according its behavior. The regional climate is temperate subhumid, the mean precipitation is 830-950 mm and shows an upward trend in last decades. The area has morphology blocks, covered by Quaternary secuences and differentially diagenized aeolian and fluvial sediments (a Pleistocene paleo-drainage network). The stream has permanent regime in the mountain area and ephemeral in the plain (flow discharge = 0.08 to 200 m3/s). The channel is straight (sinuosity between 1,02 and 1,22), the gradient ranges from 0,4 to 0,72% and the width-depth ratio ranges between 1 and 30. Bed sediments are mainly poorly selected sand and gravel, and cemented sediments along some segments. Research showed that: 1) El Cano stream joined Tegua basin in the 60´s decade, because of backward erosion, overflows and channel extension. 2) The spatial distribution of these processes was controlled by the structure and Pleistocene paleo-drainage network, while rate and resulting morphologies were controlled by the lithology; 3) Climate is the main cause of integration (extraordinary floods in rainy years) enhanced by human activities; 4) the drainage network is still in adjustment and five morphodynamic segments are recognized.

Palavras-chave : Fluvial systems; Integration; Morphodynamic; Environmentals problems; Córdoba.

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