Summary #
The water cycle is the continuous global process by which water moves between the atmosphere, land surface, and underground — evaporating, condensing, precipitating, and infiltrating in a never-ending loop. Understanding the water cycle is foundational to understanding how watersheds function and how contamination moves through them.
The Water Cycle #
The water cycle is the most important process in a watershed. It operates identically around the world — a continuous process of water movement in which the total amount of water never changes, only its form: liquid, solid, or gas.
Solar energy drives the cycle by creating heat that evaporates water from oceans, lakes, streams, and plants. (Water evaporated from plants is called transpiration.) The gaseous water vapor rises into the atmosphere and condenses around dust particles into clouds. Clouds gradually increase in size and weight until precipitation begins. Rain or snow brings the condensed water back to earth, where it soaks into the ground and refills oceans and lakes.
Water that enters the ground is said to infiltrate or percolate into the soil. This water is either stored as groundwater when it reaches the saturation zone — where all spaces between rock particles are filled with water — or flows through the ground to discharge into a stream or lake.
[A water cycle diagram would be helpful here — consider adding one from the Media library when available.]
Related Pages #
- What is a Watershed?
- Ground Water
- Drinking Water
- Watershed Assessment Hub (Watershed Tools — Watershed Assessment)
Source and Last Reviewed #
Source not explicitly cited in original text. Content consistent with standard watershed education materials.
Last reviewed: 2026-03
Tags: monitoring, education, volunteer, practitioner
