systems are all around us. By learning how these
systems work, we gain the understanding and tools needed to protect them.
The Hydrological Cycle
Water does not stay still, it is always moving. Its endless cycle involves lakes, rivers, oceans, the atmosphere, clouds, trees, plants, animals and humans. All living beings are connected and need water to survive. The endless circulation of water between the atmosphere and the earth is called the hydrological cycle. The hydrological cycle is made up of six steps:
- Evaporation
Water from oceans, lakes, streams and rivers is heated by the sun and rises as an invisible vapour into the atmosphere
- Transpiration
Water is released from the leaves of plants as an invisible vapour that goes into the atmosphere
- Condensation
The invisible vapour found in the atmosphere cools off, turns into liquids or solids, and then gathers together to form clouds
- Precipitation
Rain, snow, ice and hail come from clouds and fall from the sky, back down to earth
- Runoff
Precipitation that has fallen to the ground, stays on top of the soil and eventually flows back into a water source
- Percolation
Precipitation that penetrates the soil's surface sinks into the earth until it reaches the watertable (the level at which water stands in a shallow well)
To learn more about the hydrological cycle, visit www.ec.gc.ca/water/en/nature/prop/e_cycle.htm
