The Rio Guaporé is a major river forming a 920-kilometer border between Brazil and Bolivia, flowing through the state of Rio Grande do Sul in Brazil. It is a clearwater tributary of the Mamoré River, which feeds into the Madeira and ultimately the Amazon River system. The river basin is ecologically rich, featuring extensive seasonally flooded forests and savannas that provide abundant food sources for aquatic life. The Guaporé is known for its remarkable biodiversity, with literature suggesting over 600 different fish species inhabit its drainage, making it one of the most species-rich rivers for aquatic plants and fish in the region. The river's average discharge near its mouth is substantial, with historical averages around 2,430 cubic meters per second, though it can fluctuate seasonally from a minimum of 370 to a maximum of 5,200 cubic meters per second. The river forms the border of the expansive Guaporé Biological Reserve, a protected area of over 615,000 hectares.