Hydrological cycle and its components Ι Components of hydrological cycle.
The hydrologic cycle begins with the evaporation of water from the surface of the ocean. As moist air is lifted, it cools and water vapour condenses to form clouds. Moisture is transported around the globe until it returns to the surface as precipitation.
Once the water reaches the ground, one of two processes may occur; 1) some of the water may evaporate back into the atmosphere or 2) the water may penetrate the surface and become groundwater. Groundwater either seeps its way into the oceans, rivers, and streams or is released back into the atmosphere through transpiration.
The balance of water that remains on the earth’s surface is a runoff, which empties into lakes, rivers and streams and is carried back to the oceans, where the cycle begins again.
Lake effect snowfall is a good example of the hydrologic cycle at work. Below is a vertical cross-section summarizing the processes of the hydrologic cycle that contribute to the production of lake effect snow?
Evaporation of warm surface water increases the amount of moisture in the colder, drier air flowing immediately above the lake surface. With continued evaporation, water vapour in the cold air condenses to form ice-crystal clouds, which are transported toward shore.
Six Components of the Hydrologic Cycle are:
- Evapotranspiration – is water evaporating from the ground and transpiration by plants. Evapotranspiration is also the way that water vapour re-enters the atmosphere.
- Condensation – is the process of water changing from a vapour to a liquid. Water vapour in the air rises mostly by convection. This means that warm, humid air will rise, while cooler air will flow downward. As the warmer air rises, the water vapour will lose energy, causing its temperature to drop. The water vapour then has a change of state into liquid or ice.
- Precipitation – is water being released from clouds as rain, sleet, snow or hail. Precipitation begins after water vapour, which has condensed in the atmosphere, becomes too heavy to remain in atmospheric air currents and falls.
- Infiltration – when a portion of the precipitation that reaches the Earth’s surface seeps into the ground.
- Percolation – is the downward movement of water through soil and rock. Percolation occurs beneath the root zone.
- Runoff – is precipitation that reaches the surface of the Earth but does not infiltrate the soil. Runoff can also come from melted snow and ice.
5 Steps of Hydrological Cycle
The hydrological cycle, also known as the water cycle, is a continuous and essential process that governs the movement of water on Earth. It involves five main steps and various components that work together to ensure the circulation and availability of water throughout the planet.
Step 1: Evaporation
Component: Sun’s Energy
Evaporation is the process in which the sun’s energy heats water bodies, causing water molecules to transform from a liquid state to a vapor state and rise into the atmosphere as water vapor.
Step 2: Condensation
Components: Water Vapor, Cooler Temperatures
As water vapor rises into the atmosphere, it encounters cooler temperatures. This leads to condensation, where water vapor changes back into tiny water droplets, forming clouds.
Step 3: Precipitation
Components: Clouds, Gravity
When cloud particles become heavy enough, they fall back to the Earth’s surface as precipitation.
Rain, sleet, snow or hail can all be forms of precipitation that provide water to bodies of water and support ecosystems.
Step 4: Infiltration
Components: Soil, Rocks
Precipitation that falls onto the Earth’s surface can infiltrate the ground and be absorbed by soil and rocks. This process is known as infiltration and contributes to groundwater replenishment.
Step 5: Runoff
Components: Saturated Ground, Gravity
When the ground becomes saturated and cannot absorb more water, excess water flows over the surface, creating streams, rivers, and eventually flowing into oceans. This process is called runoff and helps transport water and nutrients.
The Impact of the Hydrological Cycle
The hydrological cycle is not only a fascinating natural phenomenon but also a lifeline for all living organisms. It sustains ecosystems, supports agriculture, influences weather patterns, and shapes the landscapes we inhabit.
The delicate balance maintained by the hydrological cycle ensures the continuous availability of freshwater resources, making it a cornerstone of Earth’s dynamic and interconnected systems.
The hydrological cycle is a symphony of interconnected components that work harmoniously to ensure the movement and distribution of water across our planet.
From the mesmerizing journey of water molecules as they evaporate into the atmosphere, to their eventual return as life-giving precipitation, each component plays a vital role in maintaining Earth’s water balance.
As we marvel at the beauty of the hydrological cycle, let us also recognize its importance in sustaining life and shaping the world we call home.