The Hydrological Cycle Overview

The Hydrological Cycle

• The hydrological cycle is a continuous process that involves the movement of water on, above and below the surface of the Earth.
• The cycle is also known as the water cycle.

Processes in the Hydrological Cycle

• Evaporation: The process of liquid water turning into water vapor, driven by heat from the sun.
• Transpiration: The release of water vapor from plants.
• Condensation: Water vapor in the atmosphere cools and changes back into tiny water droplets, forming clouds.
• Precipitation: When the water droplets in clouds become heavy enough, they fall back to Earth as rain, snow, sleet, or hail.
• Interception: Water that is caught by vegetation before it reaches the ground.
• Infiltration: The process of water soaking into the ground.
• Percolation: Water moving vertically downwards through the soil and rocks.
• Surface Run-off: Water flowing over the land surface.
• Groundwater Flow: Water flowing sideways through the soil.

Drainage Basins

• Drainage basin: The area of land where all the water drains into a particular river or lake.
• Watershed: The boundary of a drainage basin, marked by higher ground.
• Confluence: The point where two rivers meet.
• Mouth: The place where a river enters a lake, sea or ocean.