Juan Maria Carron

The Pantanal and the Paraguay River Basin: From the Technical Focus to the Political Option

(Excerpts from the full paper presented in the uncorrected, advance proof of The Pantanal of Brazil, Bolivia and Paraguay, Hudson MacArthur Publishers, copyright 2000 by Waterland Research Institute)


The confluence of the Paraguay-Paraná aquatic system with three surrounding ecosystems, the “Selva Amazónica,” the “Cerrado” and the “Gran Chaco,” facilitates an extraordinary biotic interchange, creating an impressive biodiversity which endures at present but which runs a serious risk of diminishing. Today, experts and political leaders throughout the world are focusing their attention on this ecosystem — or, more correctly, on this collection of ecosystems — with the intention of it becoming an object of sustainable development that is compatible with the preservation of its ecological character. 


However, it is too rarely emphasized that the Pantanal should not be considered in isolation but rather as forming part of the Paraguay River Basin and, even moreso, the larger La Plata Basin. The “El Gran Pantanal” should be studied, preserved and managed in relation to this larger region --- an expanse which encompasses more than 2 million square kilometers and a population of more than 100 million inhabitants, and extends through Brazil, Bolivia, Paraguay, Argentina and Uruguay. This is a natural unity that transcends the borders between nations. This is the only focus technically correct; it should be politically expressed in an agreement of a super-national or intergovernmental nature, among nations of the macro region. 


The Pantanal is located in the extreme north of a type of fluvial vertebral column, more than 3,800 kilometers long, which consists of: 

– the Upper Paraguay, from the Paraguay River’s origin until its confluence with the Apa River (1,670 km);

– the Middle Paraguay, from the Apa River to Itapirú, 47 kilometers to the south of Asunción, Paraguay (584 km); 

– the Lower Paraguay, between Itapirú and the Paraguay River’s confluence with the Paraná River (350 km); 

– the Middle Paraná, from the Paraná River’s confluence with the Paraguay River to Santa Fé, Argentina (650 km); 

– the Lower Paraná, from Santa Fé to the Río de la Plata estuary (600 km). 

Each of these sections delineate regions with distinct ecological attributes. Despite the differences, however, a marked interdependence exists among the regions, such that environmental impacts that originate in the extreme north can influence even the Río de la Plata estuary, and incidents in the lower sections can influence the biogeographical characteristics of the Pantanal. This interdependence is not irrelevant for either the regulation of the river flow or the preservation of biodiversity. For example, if the Pantanal were to lose or diminish in its capacity to be a “sponge,” in that it serves to reduce the flow of the water that enters the upper part of the basin, the consequences could be grave. Currently, the crest or river swelling that issues forth from the headwaters of the Paraguay River arrives in the lower Paraguay after some six months delay. The river crest that impacts upstream in the Pantanal in February impacts the lower Pantanal in July. If the annual cycle of flood and drought, increase and decease is altered, what would happen to the fauna and flora in the lower Paraguay? 


The Paraguay-Paraná Hidrovia Project has contributed to our knowledge of the area by showing the interdependence of the distinct regions that form parts of the basin. These environmental impact studies have confirmed in dramatic fashion some of the dangers that lie in wait for the basin (Taylor et al. 1997). Developing a system for navigation that is 3,440 km long (from Cáceres, Brazil to Nueva Palmira, Uruguay) will include deep dredging, the establishment of canals, excavation of rocky beds, realignment of channels and, moreover, the improvement of port and roadway infrastructures. Various alternatives exist with respect to the intense alterations entailed in the Hidrovia Project. The most comprehensive alternative, presented in 1996 by the firm Hidroservice Louis Berger in Asunción, anticipates the formation of: 

• Canals 100 m wide, 3 m deep for the Santa Fe-Asunción section. 
• Canals 90 m wide, 2.6 m deep for the Asunción-Corumbá section. 
• In the Corumbá-Cáceres section, within the Pantanal, segment A, from Corumbá to Lake Gaiba (Laguna Gaiba in Bolivia; Lagoa Guaiba in Brazil), would not be the object of major intervention. In segment B, from Lake Gaiba to Bacia de Bracinho, strong interventions would be necessary to widen and straighten out the curves and meandering. In segment C, from Bracinho until Cáceres, there would have to be dredging to deepen the river beds. In broad outlines, in segment B there would be 78 strong interventions, and in segment C dredging would be necessary to deepen the waterway in 64 critical straits. Also, the works required in the Santa Fe-Corumbá section would be considerable: 92 dredging operations to deepen the channel, 12 dredging operations to correct critical curves, and 23 straits of rocky bottom, in which eight would require the removal of rocks. 

Various evaluations have noted that such alterations would have diverse types of environmental impacts, as much a result of the construction of the Hidrovia as during its operation. 


Modifications in the Pantanal would negatively impact wetlands of significant biological importance that are situated in the lower sections of the Paraguay River. For this reason, Paraguay is very interested in avoiding damage to the Pantanal, not only for the sake of the Pantanal proper, but because what originates in the Pantanal will affect the wetlands of the lower Paraguay that constitute a 2.5 million hectare (25,000 km2) sanctuary, consisting of great riches in animal and plant species. Although there continues to be an interest in developing a regular navigable passageway from the Atlantic to Asunción, Paraguay desires that such be realized only while reducing to a minimum any negative environmental impact. All of the previous is situated in a macro regional context, where there is strong attention to the environment because of deforestation, erosion, overhunting and overfishing. This all points to the necessity of achieving an integrated basin management of the Paraguay and Paraná Rivers. 


 In the manner of an example, listed below are critical areas that should be the subject of integrated basin management, since these areas relate closely to the objectives of both development and ecological preservation of the Pantanal.