ABSTRACT
The Río de la Plata Basin is the second largest watershed in South America, draining an area of over 3 million km2 to the south of the Amazon basin and to the east of the Andes (Figure 30.1). The three main rivers draining this basin, the Río Paraná, the Río Paraguay and the Río Uruguay, flow through Argentina and join to form the Río de la Plata before entering the Atlantic Ocean. Large floods – that is, those with a peak discharge in excess of 38,000 m3s-1 at Corrientes – occurred on the Paraná and the Paraguay in 1812, 1858, 1878, 1905, 1912, 1923, 1929, 1966 and 1977 (Halcrow Group, 1994). In 1941 and 1959 large floods occurred on the Río Uruguay alone. More recently, large floods have occurred in 1982-83, 1986 (principally affecting the Uruguay), 1987, 1990, 1992, 1997 (principally affecting the Uruguay) and 1998. Seven out of the fifteen largest floods since 1900 have occurred between 1982 and 1998 on these rivers.
