ABSTRACT
The river basin of the Río de la Plata comprises approximately one-fifth of the South American continent’s surface. The total drainage area is 3,100,000 sq km, with Brazil, Bolivia, Paraguay, Uruguay and Argentina as riparians. The climate of the basin varies from tropical-humid to semi-arid, and water uses are diverse, ranging from irrigation (mainly for Bolivia, Paraguay and Uruguay), through industrial utilization (in Argentina and Brazil), to the very important navigation and hydropower generation. The sub-basins are the Tieté, Paranapanema, Paraná, Iguazú, Uruguay, Paraguay, Bermejo, Pilcomayo and Salado del Norte. The common terminus, Río de la Plata, springs from the confluence of the rivers Uruguay and Paraná, after 250 km forming a delta at its mouth that is 224 km long. The vast river basin, on account of its diverse ecological zones, is home to
many endemic species. The Pantanal wetlands, situated mainly in Brazil (with small parts in Bolivia and Paraguay), are a UNESCO world heritage site and a unique hub of biodiversity. Below ground, the basin is linked with the Guaraní aquifer (underlying
large parts of the riparians’ territories in Argentina, Brazil, Uruguay and Paraguay), providing recharge for the world’s largest non-fossil groundwater reservoir. Through the aquifer, the Río de la Plata basin is interconnected below ground with another major river basin of Brazil, the Río São Francisco. For the basin states, both the rivers of the La Plata basin and the pure groundwaters of the Guaraní are strategic resources. From a hydrological viewpoint, the sub-basins have differing character-
istics. According to the respective prevailing climatic regimes in the relatively vast sub-basins (given that the La Plata basin is the fifth largest basin in the world), periods of high flow occur either during winter or summer time, which at the river mouth creates a rather stable discharge. Floods are a main characteristic in all sub-basins, where long and wide floodplains act as a natural buffer for downstream areas. However, human settlement policies (and their absence in some cases) have neglected the threat since the 1960s. The floods have devastating economic effects, as industries are often situated along the river banks. The other main threat for much of the population is the pollution caused by urban and agricultural drainage. The basin states’ biggest cities are situated along the rivers, and water retention and wastewater treatment are often insufficient; the vital agricultural sector, producing wheat, soy and canola, remains largely unregulated in terms of agro-ecologic considerations
on account of fears that competitiveness would be harmed thereby. This pollution affects both the downstream areas and adjoining rice production zones, as well as the recharge of the Guaraní. Efforts to achieve a legal framework with the ability to combine the dif-
fering interests and priorities among the riparian states date back to the 1930s, when conflicts about navigation caused a war between Bolivia and Paraguay. This ended in 1935, when the two states signed a peace agreement that contained specifications about the establishment of a traffic and commerce regime mutually fostering the development of both countries. This treaty can be seen as a precedent for the legally binding framework currently in place, the 1969 Río de la Plata Basin Treaty. The La Plata treaty was facilitated by political developments in the region, such as the foundation of the Organization of American States, the Economic and Social Council of the United Nations for Latin America and the Inter-American Development Bank. Increased interest among the basin states in expanding infrastructure along the watercourses of the La Plata basin for more intensive development, and contestations during the 1960s-foremost between Brazil, Argentina and Paraguay-raised consciousness among the riparian states that, in order peacefully and mutually to come to integrated solutions in the basin, a river basin organization was needed. As a result of the basin framework, bi-national sub-basin authorities have been founded to intensify and improve bilateral and tripartite hydro-co-operation. The multilateral La Plata treaty made way for common development efforts
between Paraguay and Brazil on the Paraná. These joint efforts put an end to conflict over the Guaira waterfalls to which both countries claimed territorial rights; the decision to construct what is today one of the world’s biggest hydropower stations, the Itaipú dam, led to an immense increase in renewable energy resources for both riparians, and the contested region was thus submerged. Environmental degradation was planned to be limited through wildlife evacuation projects carried out by both states. During the 1970s, security concerns by the downstream riparian Argentina
about a dam failure and subsequent potential flooding of its capital Buenos Aires marked the persisting but non-violent frictions between it and Brazilthe two major players in this part of the basin. (The Itaipú construction was pushed by Brazilian authorities more than by the junior partner in the project.) A second hydropower station further downstream, initiated by Argentina and Paraguay, the Yacyreta dam, introduced a safety net for the aforementioned case. The umbrella-type La Plata treaty takes into account the different national
legal and administrative systems (two of which are federal). Under the auspices of the treaty, numerous bilateral agreements have been concluded between riparian states, enabling the identification of, and priorities for, potential co-operative projects and subsequently paving the way for the technical and legal provisions necessary to implement and manage projects according to joint interests.
