Streams move downslope under the influence of gravity, the passage of water is called stream flow. Several factors control the amount of. The eroded rock and soil materials that are transported downstream by a river are called its load. Road and building construction and removal of vegetation make it easier for rain to wash sediment into streams and rivers. Unit 4 Earth's. Jhaugh:File: X:Graphic Organizers Earth Science /Erosion- 6 – 3 ways streams carry sediments/J. Hoffman Note/J. Haugh Visuals.