6.1 Running Water

Water Cycle

• The constant movement of water among the oceans, the atmosphere, geosphere, and the biosphere.

Infiltration

• The movement of surface water into rock or soil through cracks and pore spaces

transpiration

• When plants absorb water and release it into the atmosphere

Gradient

• The slope of a stream over a certain distance

Stream channel

• The course that the water in a stream follows

Discharge

• The quantity of water in a stream that passes a given point in a period of time

tributary

• A stream that empties itself into another stream

Base level

• The lowest point to which a stream can erode its channel

Meander

• A looplike bend in the course of a stream

Key Concept

• Water constantly moves along the oceans, the atmosphere, the solid earth, and the biosphere. This unending circulation of Earth’s water supply is the water cycle.

Key Concept

• Balance in the water cycle means the average annual precipitation over Earth equals the amount of water that evaporates.

Key Concept

• The ability of a stream to erode and transport materials depends largely on its velocity.

Key Concept

• While gradient decreases between a stream’s headwaters and mouth, discharge increases.