The hydrological relationship between Roraima and the rivers that it feeds is worth tracing in more detail, because it illuminates the functional connection between the isolated geological feature on the summit and the vast ecological systems of the lowlands below.

Water falling on the Venezuelan portion of the Roraima summit eventually reaches the Orinoco drainage.

The Orinoco is one of South America’s great rivers — roughly 2,140 kilometers long, draining a basin of approximately 880,000 square kilometers that encompasses much of Venezuela and extends into Colombia.

The Orinoco’s flow is substantial and variable with the wet and dry seasons, and the tepui highlands of southeastern Bolívar state are a significant part of its headwater system.

Water falling on the Guyanese portion of the summit drains toward the Essequibo.