Tributary

rivers · water systems · geography

Smaller meets bigger. A tributary is like a helper stream that joins a larger river. It never flows directly into the ocean, only into another river or lake.

Part of the system. Tributaries and the main river work together to drain water from the surrounding land, collecting rain and groundwater and moving it all toward the ocean.

Many tributaries, one river. Big rivers like the Amazon or the Mississippi have hundreds of tributaries flowing into them from all directions, like branches on a tree.

Following the slope. Water naturally flows downhill, so tributaries always flow toward the main river they join, helping transport water from high areas to lower ones.