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Coursing through Brazil, Bolivia, Paraguay, Uruguay and Argentina, the Paraguay and Paraná rivers provide water and energy for South America's largest city, São Paulo; flood the world's largest wetland, the Pantanal; and thunder over the world's second-largest waterfall, Iguaçu Falls.
One hundred million people depend on the waters of these hardworking rivers for food, water, energy and transportation. The life cycles of plants and animals in the Pantanal and other wild South American landscapes have evolved to match the rivers' flow rates and sedimentation patterns. Even local businesses and the national incomes of five countries rely on these rivers to irrigate crops, generate energy and attract tourists.
The Threats
The Paraguay-Paraná river system covers nearly one million square miles — an area larger than all of Greenland. With the abundance of water flowing through South America's second-largest river system (only the Amazon is greater), it's easy to think the Paraguay-Paraná will never run short of fresh, clean water.
However, major alterations to the rivers' flow, such as dams and sedimentation, as well as pollution, silting and deforestation, pose serious threats to these waters that nourish so much human, plant and animal life.
Farming Water
South America's largest city, São Paulo, is faced with the difficult task of supporting a growing population with dwindling water resources. The Piracicaba-Capivari-Jundiaí watershed within the Paraná River basin supplies half of the São Paulo metropolitan area's 18 million residents with drinking water, but deforestation, sedimentation and pollution upstream are threatening the supply.
In fact, the need to chemically treat water for São Paulo's residents has risen 51 percent in the past five years — a significant expenditure that could be avoided if upstream waters were protected and clean.
That's why the Conservancy helped set up Brazil's first Water Producer Program, which uses fees collected by watershed committees to provide landowners with financial incentives for protecting and reforesting critical riparian areas on their properties.
The Conservancy is replicating the Water Producer Program in other major Brazilian watersheds and hopes to initiate a similar project in the unique dry shrublands of the Paraguayan Chaco.
Seeing the Future
Development around the Paraguay-Paraná river system is accelerating, with major agriculture and infrastructure projects planned for coming years. More than half of Brazil's extensive Cerrado grasslands have already been converted for ranching and agriculture — industries responsible for most of the soil erosion and pollution running directly into the river system.
The Conservancy has teamed up with IBM and other partners to create a computer modeling tool that acts like a technological crystal ball, enabling government and private-industry leaders to make more conservation-friendly decisions about the potential freshwater impacts of large infrastructure and land-use projects before they're even built.
It will also enable assessments of how landscape planning and water and soil conservation activities are improving water quality and sustaining biodiversity in places downstream, like the Pantanal.
Photo credits (top to bottom, left to right): Cuiabá join the Paraguay River inside the Pantanal National Park, Pantanal, Brazil © 2005 Scott Warren; Small wooden fishing boats moored on a lake below the hills east of Curitiba, in the state of Parana, Brazil © 2005 Scott Warren; Paraguay-Paraná River system map © TNC; © TNC
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