Page 27 - GENERACION Y TRANSPORTE DE SEDIMENTOS

Executive Summary

he Bermejo River Basin covers an approxi- The average annual liquid flow downstream of
Tmate area of 123,000km², developing its the junction of the Bermejo River with San Francis-
headwaters in the Argentine provinces of Salta co River is 446m /s, representing 2.5% of the mod-
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and Jujuy, and in the Department of Tarija, in Bo- ule of the Parana River in Corrientes. In contrast,
livia. Of the total area, approximately 50,000km² the supply of solid flow far exceeds said number.
are hydrologically active, called High or Upper Considering the full range of suspended solids dis-
Basin, with characteristics of mountain rivers charge measurements, the solid contribution to the
watercourses. Then, the Middle and Lower Ba- Paraná by the Bermejo is about 75% of the total of
sins (also called Lower Basin as a whole), devel- such river, a figure which grows if recent decades
oped along the border between the provinces of are considered due to the execution of reservoirs
Chaco and Formosa, as a NW / SE corridor about in Brazil. The high production of sediments in the
90km wide, with characteristics of a plain up to basin is the result of the distinctive feature of the
the mouth of the Paraguay River. Bermejo River, which contributes about 100 million
From a hydrological view, the Bermejo Basin tons of sediments annually to the Paraguay-Paraná-
presents an extended period of recession and a Delta and Río de la Plata system .
limited period with high flows derived from heavy Among the rivers of the Upper Bermejo River
rains of the summer period. As for rainfall, the Basin, the Pescado River deserves special mention.
Basin presents mean annual precipitation values Its major tributary if the Iruya River, with high sedi-
above 1,200mm at the ends, decreasing toward its ment yield (10,000Tn/km /annually) and the San
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center, below 600mm. Francisco river, formed by the rivers Lavayen and