Water Cycle Processes

There are many different processes which connect the water stores of the water cycle. Read more about each of these processes below.
Water Cycle Processes combined in 8 separate images. Condensation is shown as water vapor condensing into clouds. Precipitation shows dark clouds along with rain, sleet, snow, and mist. For evaporation, there are red arrows from the ocean to the atmosphere. Transpiration shows red arrows from the leaves to the atmosphere. For surface runoff water is flowing down a hill. Groundwater is demonstrated as water flowing in narrow channels underground. For infiltration, surface water is being absorbed into the soil. Interception shows rain landing on a tree canopy.
Figure 1: Water cycles through the environment via these processes.

Evaporation occurs when the sun’s radiation heats up the Earth’s surface, causing liquid water to become water vapor (gas). Most water is evaporated from the oceans, but some of this water precipitates over land and contributes to freshwater stores.

Transpiration is the movement of water through plants. Plants uptake water from the soil via their roots. It travels up the xylem and through the veins to be dispersed throughout the plant. Water exits via stomata (small pores in the leaves) and evaporates from the leaf surface.

As water vapor in the atmosphere rises it begins to cool. This causes the water vapor to condense into water droplets and forms clouds.

Water droplets in the atmosphere fall to the Earth’s surface in a process known as precipitation. Precipitation includes rain, hail, snow, sleet and mist.

Some of the water which precipitates over land is absorbed into, or infiltrates, the soil. This is known as infiltration.

During precipitation some water does not directly reach the soil, and is instead intercepted by things such as trees, leaves and rocks. This intercepted water either evaporates or slowly falls to the soil.

Surface Runoff
Precipitation which is not intercepted or able to infiltrate the soil flows over the surface, from high to low areas, usually into streams or rivers. This is known as surface runoff.

Groundwater Flow
Groundwater flow describes the slow movement of groundwater underground. The direction of flow depends on elevation and pressure. Groundwater flow can travel from high to low elevation, or from areas of high to low pressure.