The water cycle, also known as the hydrologic cycle, describes the continuous movement of water above, on, and below the surface of the Earth. Water goes through different phases and processes during this cycle, transitioning between liquid, vapor, and ice. There are seven major stages of the water cycle that occur in a continuous loop.
The 7 Stages of the Water Cycle
The seven stages of the water cycle in order are:
- Evaporation
- Condensation
- Precipitation
- Infiltration
- Runoff
- Storage
- Transpiration
These stages depict how water moves around Earth’s surfaces, oceans, and atmosphere. Water changes states, transitions, and transforms throughout the water cycle. Understanding each stage provides deeper insight into this important natural process.
Stage 1: Evaporation
Evaporation is the first stage of the water cycle. It occurs when heat from the sun causes water at the surface to turn from liquid to gas or vapor. Water evaporates from oceans, lakes, rivers, wetlands, soils, and any open bodies of water exposed to the air. Plants lose water to evaporation through their leaves, called transpiration (which will be explained more later). Evaporation accounts for about 90% of the water vapor in the atmosphere.
The rate of evaporation depends on several factors:
- Temperature – Heat increases the energy of water molecules, allowing them to more freely escape from the liquid state into vapor.
- Surface area – The larger the exposed surface area of water, the greater the potential for evaporation.
- Wind speed – Increased wind flow accelerates evaporation by removing water vapor from the boundary layer over water bodies.
- Humidity – High humidity slows evaporation because the air is already saturated with water vapor.
As liquid water evaporates, it takes heat energy with it. This heat loss cools the environment where evaporation is taking place. Fast rates of evaporation lead to a pronounced cooling effect.
Stage 2: Condensation
Condensation is the second stage of the water cycle. It occurs when water vapor in the air cools and changes back into liquid water. Condensation is the opposite process of evaporation.
As moist air rises into the atmosphere, it expands and cools. Cooler air cannot retain as much moisture. When the air becomes saturated or exceeds its dew point, condensation occurs. The water vapor condenses onto tiny particles floating in the air, forming clouds. Clouds are simply visible masses of condensed water droplets or ice crystals.
Other examples of condensation in the water cycle include:
- Dew forming on grass and other surfaces overnight
- Water droplets beading on the sides of a glass of ice water
- Fog appearing over bodies of water
The process of condensation releases heat energy back into the atmosphere. This heat warms the surrounding air.
Stage 3: Precipitation
Precipitation is the third stage of the water cycle. It occurs when condensed water droplets in clouds become too heavy and fall back to Earth. Precipitation includes rain, snow, hail, sleet, and other forms.
Some factors that affect precipitation rates and amounts include:
- Temperature – Warm air holds more moisture than cold air, influencing precipitation amounts.
- Wind – Strong upward winds support the formation of precipitation by lifting moisture high into the atmosphere.
- Geography – Mountains force air upwards, causing precipitation on windward slopes.
- Humidity – More humid air creates favorable conditions for condensation and precipitation.
Most precipitation falls back into the oceans or onto land. This replenishes surface waters and moisture in soils. Precipitation is a vital source of freshwater for humans, plants, and animals.
Stage 4: Infiltration
Infiltration is the fourth stage of the water cycle. It is the process by which water soaks into the ground, filling the pores in soil, sand, and rocks. On the land surface, infiltration occurs any time precipitation falls or surface water flows over permeable materials.
Water infiltrates into the ground because of gravity and capillary action. The rate of infiltration depends on the soil characteristics. Sandy or loamy soils allow faster infiltration than clay soils. Saturated soils or dense bedrock inhibit infiltration. Vegetative ground cover helps slow runoff, allowing more time for infiltration. Impervious surfaces like concrete prevent infiltration from occurring.
Infiltrated water becomes part of the zone of saturation below the water table. This groundwater later flows out in streams or springs, replenishing surface water. Plants take up some of the infiltrated moisture through their roots.
Stage 5: Runoff
Runoff is the fifth stage of the water cycle. It involves the downslope movement of water over the land surface towards stream channels, lakes, or oceans. Runoff collects from excess precipitation that cannot infiltrate into the ground or evaporate.
Surface runoff occurs when rainfall rate exceeds infiltration rate, creating overland flow. Throughflow happens when infiltrated water moves laterally through soil layers until reaching an impermeable surface and emerging as springs or seeps. Groundwater runoff results when groundwater emerges due to water table intersecting the land surface.
Factors affecting runoff rates include:
- Precipitation amount – Higher rainfall yields more excess water for runoff.
- Soil moisture – Drier soils allow more infiltration, decreasing runoff potential.
- Topography – Steeper gradients increase runoff velocity and amounts.
- Vegetation – Plants intercept precipitation and improve infiltration, reducing runoff.
Runoff collects into streams and lakes. This provides renewable freshwater vital for aquatic ecosystems. Runoff also carries sediments, nutrients, pollutants, and other substances as it flows towards bodies of water.
Stage 6: Storage
Storage is the sixth stage of the water cycle. It involves the processes that temporarily hold water for varying lengths of time as it moves between Earth’s surface and atmosphere. Oceans, lakes, rivers, glaciers, groundwater, soil moisture, and atmospheric water vapor are all stores of water.
Oceans contain about 97% of Earth’s water. This makes them the largest storage sink in the water cycle. Water remains in ocean storage for centuries or millennia. Lakes trap runoff and river outflow, with retention times of decades. Rivers and streams hold water for days or months as it flows downstream.
Glaciers and polar ice caps are long-term stores of frozen water. Groundwater reserves far exceed surface freshwater. Water can remain stored underground for thousands of years. The atmosphere also acts as storage, holding water vapor for an average of just 9 to 10 days.
Water continually cycles between these storage sinks through various processes like precipitation, runoff, infiltration, and evaporation. The volumes and times water spends in each state of storage are constantly in flux.
Stage 7: Transpiration
Transpiration is the seventh and final stage of the water cycle. It is the process through which moisture in plants moves upwards from the roots, through vascular tissue in stems and leaves, and exits into the air as water vapor through leaf pores or stomata.
Plants absorb water from the soil through their root system. Photosynthesis drives water up through the xylem tissues. Excess water vapor diffuses out the plant stomata. Wind carries the moisture away as transpiration. On hot or windy days, plants transpire water at faster rates.
Some key facts about transpiration include:
- Around 10% of the total water in the atmosphere comes from transpiration.
- Plants release an average of 10% of their weight in water per day.
- Just 1 acre of corn gives off 3,000-4,000 gallons of water each day through transpiration.
Transpiration generates suction pressure in plant stems that pulls more water from the roots. This facilitates the upward transport of moisture and nutrients needed for growth.
The Water Cycle Continues
The water cycle is a closed continuous loop. Water stored in oceans, ice, groundwater, lakes, soil, and plants keeps cycling through various processes, phases, and pathways. There is no real start or end point. The seven major stages interconnect to transport moisture around Earth’s surface and atmosphere through evaporation, condensation, precipitation, infiltration, runoff, storage, and transpiration.
The sun provides the energy source driving the water cycle through heat powering evaporation. Gravity acts to pull water back down to the surface as precipitation. The laws of physics and chemistry govern the behavior and changes of state of water molecules through the cycle. Plants play a vital role in transferring groundwater into the atmosphere through transpiration.
The cycling of Earth’s water is an ancient process that has been operating for over 4 billion years. The water cycle continuously purifies and redistributes the planet’s fixed supply of water. It provides freshwater to support life on land. The stages and flow rates can vary over different time scales from days to millennia. But the cyclic momentum of the hydrosphere remains steady, ensuring water’s next phase of transition in an elegant, enclosed loop.
Frequently Asked Questions About the Water Cycle Stages
What are the 4 main stages of the water cycle?
The four main stages of the water cycle are:
- Evaporation – Liquid water converting into water vapor
- Condensation – Water vapor changing back into liquid water
- Precipitation – Condensed water falling from clouds
- Collection – Water collecting in oceans, lakes, rivers, and groundwater
Evaporation and condensation drive the lifting of water into the air and formation of clouds. Precipitation brings it back down to Earth’s surface where collection stores water for future cycling.
What are the 5 main stages of the water cycle?
The five main stages of the water cycle are:
- Evaporation
- Condensation
- Precipitation
- Infiltration
- Runoff
Compared to the four stages, this separates out infiltration of water into groundwater from general collection and also includes runoff as a distinct process. All five help transition water between the Earth’s surface and atmosphere.
What are the 6 main stages of the water cycle?
The six main stages of the water cycle are:
- Evaporation
- Condensation
- Precipitation
- Infiltration
- Storage
- Transpiration
This expands the stages further by isolating storage and transpiration. Storage allows water to reside in oceans, ice, groundwater, lakes, soil, and the atmosphere for various amounts of time. Transpiration accounts for how plants return water vapor to the air through leaves.
What are the 9 stages of the water cycle?
Some models of the water cycle describe up to 9 different stages:
- Evaporation
- Evapotranspiration
- Condensation
- Precipitation
- Infiltration
- Percolation
- Storage
- Surface Runoff
- Ocean Storage
This very detailed version splits evapotranspiration and ocean storage out from the main stages. It also includes percolation, or downward seepage through soil and rock as part of infiltration. The key processes describing water’s movement through air, land, and sea are captured in these comprehensive nine stages.
What are the 7 main processes of the water cycle?
The seven main processes of the water cycle are:
- Evaporation
- Condensation
- Precipitation
- Transpiration
- Surface Runoff
- Infiltration
- Groundwater Discharge
This characterizes the main actions or mechanisms moving water. Surface and groundwater flows are distinguished rather than lumped together as storage. Transpiration accounts for plants releasing vapor. Overall, these key processes connect to generate continuous hydrologic cycling.
How can the water cycle be explained?
The water cycle can be explained as the continuous circulation and conservation of Earth’s water. It involves processes that change, transport, and store water as it moves between the ground and atmosphere. Evaporation and transpiration turn liquid water into vapor. This vapor then condenses into clouds before falling back as rain, snow, or other precipitation. Water flows over or into the ground, where it’s held in glaciers, oceans, waterways, and groundwater. Water returns to the air through evaporation and plant transpiration to repeat the cycle again and again.
Why is the water cycle important?
The water cycle is extremely important because it provides renewable freshwater to support life on land. The cycling of water from air to earth and back again purifies water and regulates global temperatures. The movement of water and changes of phase require energy from the sun, making the water cycle vital to climate and weather. All life depends on the availability of potable water made possible by Earth’s elegantly closed and balanced hydrologic cycle.
How does the water cycle work?
The water cycle works through the continuous circulation of water between the ground and sky. The sun’s energy powers evaporation of liquid surface water into water vapor gas. This moisture condenses into clouds before falling back down in the form of precipitation. Rainwater and meltwater collect into rivers, lakes, oceans, glaciers, and groundwater. A portion evaporates again and plants release transpired water. These processes work in a loop to keep Earth’s water moving in a balanced cycle.
