Represa de Balbina is a large reservoir on the Uatumã River, located approximately 170 km from Manaus in the municipality of Presidente Figueiredo, Amazonas state. Created by the Balbina hydroelectric dam, which was built between 1985 and 1989, the reservoir covers roughly 2,360 square kilometers, making it an exceptionally expansive body of water set within the Amazon rainforest.

The sheer scale of the reservoir defines the paddling experience here. Access to the water typically involves traveling around 8 km by road from the town of Balbina before reaching the lake's edge, where small boats and canoes are the standard means of navigation. The low density of people on the water — a consequence of the reservoir's vast surface area — means paddlers can expect considerable solitude across much of the lake.

Wildlife interest centers heavily on fish. The reservoir supports notable populations of tucunaré (Cichla sp.), including speckled peacock bass and butterfly peacock bass, as well as silver arowana. These species proliferated after the reservoir filled and have sustained active fishing since the late 1980s. The surrounding landscape is Amazonian rainforest, and the reservoir contains numerous islands — remnants of the flooded terrain — which fishermen use as base camps and which would serve as navigational landmarks for paddlers.

The Amazon hydrological cycle, with its distinct flood and ebb seasons, influences conditions on the reservoir and affects access to various parts of the lake throughout the year. Paddlers should account for the remote character of this location, the distances involved in crossing or exploring the reservoir, and the exposure to tropical weather, including storms, that characterizes the region.