Johan F. Gottgens
 
 

The Paraguay-Parana Hidrovia: Large-scale Channelization or a "Tyranny of Small Decision"
 
 

(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.)


 


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The Pantanal is a key hydrologic resource in South America. It sustains flows in the Paraguay River throughout both the wet and dry seasons, which has a major impact on both the ecology and economics of the region between the Pantanal and the Atlantic Ocean. It is also an integral part of the hydrologic cycle of South America, due to its size and the quantity of water it temporarily stores annually (Ponce 1995). 

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The seasonal flooding regime supports a productive and diverse fauna, including some of Brazil's most endangered species (The Nature Conservancy 1994). The Pantanal has one of the most diverse avian communities on the planet with more than 650 species of birds identified. In addition, more than 400 species of fish have already been listed for only a portion of the Pantanal (Marins et al. 1981). The diversity of interacting habitat types and the direct connection with neighboring South American phyto-geographic regions also produce a remarkable, albeit poorly known, plant diversity. In spite of this extraordinary productivity and diversity, the Pantanal is an unknown tropical wetland (Bucher et al. 1993) and our understanding of the forces that control the composition and functioning of its communities is meager at best.

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In this article, I briefly summarize the history surrounding a proposed 3,440 km long navigational transport artery through the Pantanal (known as the Paraguay-Paraná Hidrovia) and I make comparisons with past large-scale hydrological works in other regions to provide an understanding of its potential impact. Now that this project may have changed to a multitude of smaller-scale activities, I suggest that this Hidrovia may become yet another case of the "tyranny of small decisions" (cf. Odum 1982) and I present some ways in which such a scenario might be prevented. 

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The development of a Paraguay-Paraná Hidrovia is by no means a new idea and the river system has been navigated for many decades. More than 100 years ago, politicians and entrepreneurs already dreamed about a channelized waterway into the heart of South America. In the late-1980s, the La Plata Basin countries (Argentina, Bolivia, Brazil, Paraguay, and Uruguay) resolved to initiate this huge project as a step toward the integration of the Basin countries (Bucher et al. 1993). They created an Intergovernmental Committee on the Hidrovia (CIH) to promote and oversee the development of this commercial waterway. The waterway would link the five countries and would promote a regional integration among countries of the Mercosur (i.e., southern common market) by ensuring year-round navigational transport of minerals and agricultural products (primarily soybeans) from landlocked regions to major markets along the Atlantic coast. The goal was to transform the meandering river into a deepened channel, navigable for barges up to 2.8 m drafts during the low-water months. Presently, the river allows much smaller barge transport. An economic feasibility study (Internave 1990) actually showed a positive net return for an engineered system of major channel straightening, dredging, and removal of flow-impeding rock outcrops. The Internave report did not, however, consider the large environmental costs of the channel including changes in water quality and flood amplitude (Bucher et al. 1993), and loss of wetlands. 

Between 1995 and 1997, new engineering, economic, and environmental assessments of the proposed waterway were sponsored by the Inter-American Development Bank (IDB) and the United Nations Development Program (UNDP) and carried out by several international consortia of consultants. These studies concluded that the Hidrovia would benefit the region by reducing transportation costs, improving commerce and economic revenues, and stimulating industrial development, with little impact on the environment. 

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For example, a panel of specialists (Hidrovia Panel of Experts 1997) reviewed the results of the hydrological analyses and concluded that the engineering studies were incomplete, did not address the long-term implications of water-level changes on the floodplain, and that a thorough environmental assessment was lacking. In particular, the panel questioned whether the proposed dredging and rock blasting in the Paraguay River would lead to additional blasting requirements once the river adjusted to a new hydrologic equilibrium. In addition, the panel expressed serious considerations about the one-dimensional flow-routing models that were used and their suitability for depicting the complex interactions between surface and groundwater, their spatial and temporal variability, and the interactions between the river and the floodplain, including effects on the flora and fauna of the Pantanal. 

The panel findings were similar to the conclusions reported independently by Hamilton (1999). He used a model to predict that large losses of flooded area were possible with seemingly minor decreases in river levels, particularly during the dry season, when such areas serve as critical refuges for fauna dependent on aquatic environments. For instance, lowering the level of the Paraguay River by an average of only 25 cm, certainly a realistic estimate of potential effects of the Hidrovia, would reduce the flooded area of the Pantanal by 22% at low water. This is the equivalent of an area 2-3 times the size of the remaining Florida Everglades! Such lateral movement of water in the form of flood pulses is critical for the preservation of the floodplain. 

Similarly, longitudinal flood pulses along the course of the river are important. Navigational works would accelerate the velocity of the water, rather than maintaining its natural flow. Potential flood hazards downstream, resulting from such works, were also insufficiently represented in the CIH-authorized assessments. The majority of the water that enters the Pantanal leaves through evaporation after remaining for months in flooded areas of the basin. This storage and gradual release of flood water produces a delay of about three months in flood peaks between the head waters in Cáceres and Ladario, some 700 km downstream (Figure 1). . . . By storing flood waters, the Pantanal contributes to the separation of the flood peaks of the Paraná and Paraguay rivers downstream. Historically, the Paraguay River adds its flood stage to the Paraná River south of Resistencia (Argentina) about two to three months after its own flooding. With the present increase in agricultural development of the flood plain and dredging of the river, the peaks of the Paraguay and Paraná already have become less separated and have started to produce unusually high river stages. 

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Storage of water in the floodplain and reduced water velocity in the rivers may also have water quality benefits. This is particularly important for people depending on the rivers as a source of drinking water. Mineral uptake by plants in the productive wetlands, settling of sediments (and the chemicals sorbed to sediments) from stagnant water in the floodplain, and active microbial processing influence the chemical composition of water that flows through the Pantanal. Reduced storage, increased river flow, combined with dredging, rock blasting and river transport of hazardous materials (such as mining products and fuel) may threaten the drinking water supply of millions of people downstream. 

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Navigational improvements to enhance transportation can have great benefits in terms of economic integration of the region, lowering transportation costs for agricultural and mining products, and access to ports for land-locked countries such as Bolivia and Paraguay. As a matter of fact, such considerations generally have driven commercial waterway construction in the past, including massive works along the Mississippi, Rhine, and many other rivers. Such trade routes promote urban and industrial development and open new areas for agricultural expansion. The construction sector will greatly benefit with essentially a never-ending workload scenario of infrastructure and flood control projects. The navigation industry will also prosper with continued dredging and channel maintenance contracts, and large agribusiness will benefit, at least theoretically, from reduced transportation costs. For Argentina, in particular, the waterway is vital since 75% of its population lives in the La Plata Basin, the region most affected by the project (Gomes 1997). Paraguay and Bolivia are both still dependent on road transport of agricultural and industrial products through Brazil. 

The CIH-directed assessment, however, fell short of a comprehensive analysis of the costs involved in this project. Alternative transportation routes for Brazilian products including railroads and other existing hidrovias were not adequately considered. Even the present-day Paraguay River is navigable during at least half of the year (Filho and Coelho 1997). Soybean harvesting and shipping in the Pantanal occur in April, May and June, when the river is full and presents little problems for navigation. Consultants also overestimated the project benefits, such as the value of iron ore and soybean exports, and underestimated its significant costs, such as the loss of fisheries. Environmental costs were not fully assessed. 

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Finally, channelization of the river would negatively affect the livelihoods of thousands of indigenous people in this vast region. These vulnerable populations were never really included in the planning of this waterway. Under modern-day conventions, they cannot exert rights to remain in their traditional territories. They will likely lose these lands, vital grounds for their survival, to entrepreneurs and land speculators (IUCN 1997). This, in turn, will eliminate their traditional economies and result in despair and forced displacement. Disregard for indigenous populations has been a common feature of large-scale waterway projects throughout the world. The Hidrovia waterway seems to repeat this delinquency. 

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As the plans to develop the Hidrovia progressed, other countries were trying to undo the damage that dikes and artificial waterways have done to many of the world’s large rivers such as the Florida Everglades/Kissimmee River complex, the Missouri-Mississippi river system, the Rhine, Danube, Nile, and many others. This irony certainly did not go unnoticed with proponents of the waterway project. They emphasized that these engineered hydrological systems have been developed in many parts of the world and have produced significant industrial and agricultural benefits for those regions. The United States uses its rivers for commercial navigation and has a network of some 47,000 km of hidrovias, transporting about 670 million tons of products annually, nearly 17% of its total production. In the early 1990s, the 170 km-long connection between the Rhine and the Danube rivers in Europe was completed, connecting the North Sea with the Black Sea along a continuous hidrovia of 3,500 km (Padilha 1997). Opponents of the Paraguay-Paraná Hidrovia, on the other hand, point to the enormous long-term costs that have resulted from these same projects, particularly in terms of what economists call “externalities.” These costs (monetary or otherwise), borne by someone other than the individuals using a resource, include damages due to flooding, deteriorating drinking water quality, displaced populations, pollution, loss of wetlands and wildlife, and damage to fisheries (cf. Bucher and Huszar 1996). 

What is perhaps most striking is that these damages were hardly ever the result of a single adverse decision. Rather, they generally resulted from a series of small-scale, seemingly independent decisions on resource use that accumulated over time and produced a large-scale undesired outcome. This “tyranny of small decisions,” first used in economics by Kahn (1966) and later adapted to environmental degradation (Odum 1982), may very well guide the fate of the Pantanal in the next decades. No one may deliberately plan to destroy this enormous floodplain, but small-scale decisions to bring additional farmland into production, to construct yet another port, to carry out additional dredging for navigation in shallow river stretches, to dig another drainage canal to prevent flooding, and to build one more road to improve access may produce a cumulative and irreversible consequence. Recent history shows many examples. 

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The Florida Everglades were not ruined by a one large-scale and detrimental choice. Instead, many smaller, ostensibly independent choices contributed to what is now one of the largest ecological restoration efforts ever undertaken. 

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Similarly, the impacts from the gradual development and use of the Missouri-Mississippi river system may be used as a comparison, although there are several apparent differences between this navigable waterway and the Paraguay River within and downstream of the Pantanal (e.g., climate, soils, and precipitation patterns). There are, however, enough similarities in scale, flow, channel geomorphology, and connectivity with riparian habitats between these river systems, so that impacts of water-related developments on the lower Missouri-Mississippi rivers during the past 175 years may help illustrate some likely impacts of the Hidrovia on the upper-Paraguay River and the wetlands of the Pantanal in the next 100 years. 

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Changes to the structure and flow pattern of the Paraguay River could lead, based on the Mississippi-Missouri model, to a similar disruption of the link between that river and the Pantanal. Even though the focus of the Hidrovia was on navigational improvements, this waterway would inevitably evolve into a multi-faceted, economic development enterprise, where a multitude of seemingly independent decisions and projects compete for the same resource. Again, the Hidrovia may become another lesson of Alfred Kahn’s (1966) and Bill Odum’s (1982) “tyranny of small decisions.” No one may be making the deliberate choice to destroy the Pantanal floodplain system. Yet, because of the cumulative effect of many small actions, the Pantanal of the 21st century may well be as different from its present state as the Everglades and the Mississippi-Missouri rivers differ from their pre-1900 condition. 

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 In early 1998, Brazil’s Federal Environmental Agency (IBAMA) announced a halt to all plans for construction activities along the Brazilian portion of the waterway. The Brazilian court system actually ordered a suspension of all studies and engineering works by the federal government for the implementation of the Paraguay-Paraná Hidrovia. Instead, Brazil chose to emphasize smaller, non-structural improvements. Does that mean that the project is history? The will to construct the Hidrovia may very well persist and, as long as there is an economic interest in increasing barge traffic on the river, the channelization could be implemented in pieces, and without environmental controls.

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Such activities include port construction in Cáceres and dredging of the Paraguay River well-beyond the historical survey depths. Other countries in the region still seem determined to carry out extensive dredging and channel straightening along the course of the rivers. Dredging of the Tamengo channel, Bolivia’s link to the waterway near the Brazilian river city of Corumbá, has been on-going. The Argentinian government continues to dredge the stretch of the Paraná River between Buenos Aires and Santa Fé. Rock blasting by Paraguay has occurred in spite of pledges to protect the Pantanal. Transportation interests, agribusiness, mining sectors and construction companies still push for a commercial waterway, which may now be implemented in a piecemeal fashion.

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Dredging and river straightening downstream will still impact the hydrology and ecology of the upstream Pantanal. The whole system is interdependent and separate smaller projects, that are less subject to comprehensive planning and environmental oversight than a single large project, may actually produce a worse outcome than a comprehensively planned project. As Odum (1982) pointed out, such cumulative effects of smaller projects can be avoided only if planners, politicians, scientists, and engineers adopt a large-scale, holistic perspective that is similar to the ecosystem approach recently outlined for large river systems by Sparks (1995) and for South America’s Gran Chaco by Bucher and Huszar (1999). Perhaps a master plan for the Pantanal is needed. Certainly, such a plan should embrace a perspective that includes consideration of the cumulative impact of all the little decisions and bypasses the pressures of short-term rewards obtained with short-sighted solutions. Only then will we not repeat the same mistakes made in so many other large river and wetland systems. 

 

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