Abstract

VAZQUEZ, Pablo Mauricio; CABRIA, Fabián Néstor; ROJAS, María Del Carmen  and  CALANDRONI, Mirta Beatriz. Flooding risk in the Salado River Basin. Cienc. suelo [online]. 2009, vol.27, n.2, pp.237-246. ISSN 1850-2067.

It is well documented that the lower basin of the Salado River has been always exposed to frequent floods. Nevertheless, from 1986 to 2001 the cultivated surface of the Flooding Pampas increased by 69%, being this agricultural expansion mostly over lands that have been periodically affected by floods. A flooding risk analysis was carried out in order to assist with the planning and disposition of farming activities in the Flooding Pampas. For this purpose, the recurrence of precipitations was calculated over 20 meteorological stations, and linked to a by-pixel flooding frequency layer resultant from an analysis of a time-series of satellite images. Results denote that extreme events of accumulated precipitation have been registered in all seasons, being autumn and winter flooding events more prolonged than the spring and summer ones. Even though autumn and winter had similar flooding durabilities, autumn turned out to be the critical season as a result of a higher frequency of flooding events in April and May. Severe flooding could occur when precipitations exceed 150-200 mm, as precipitation accumulations of these magnitudes were related to flooded areas equivalent to 68.76% of the region (5,844,709 ha). Anthropic structures contributed to as much as 2.11% of the regional flooding, as shown by the flooding pattern of the region, being channels 12, 11 and 9, as well as the provincial highway No. 9 and the train rail from Metrovías the main impediments for the water flow. For the 2003-2004 period, we deter-mined through remote sensing techniques that 22.8% of the surface with crop production (173,571 ha) corresponded to areas with a flooding recurrence higher than 40%, whereas only 7.98% of the surface with sown pastures (51,504 ha) corresponded to risky areas.

Keywords : Flooding; Recurrence; Salado River Basin.

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