On the planet earth, most of the freshwater exists as ice caps and gla...
Out of all the water on Earth, salt water in oceans, seas and saline groundwater make up about 97% of it. Only 2.5– 2.75% is fresh water, including 1.75–2% frozen in glaciers, ice and snow, 0.7–0.8% as fresh groundwater and soil moisture, and less than 0.01% of it as surface water in lakes, swamps and rivers
On the planet earth, most of the freshwater exists as ice caps and gla...
The correct answer is option 'C', which states that the largest proportion of freshwater on Earth exists as groundwater. Let us understand why this is the case and explore some key points related to the distribution of freshwater on our planet.
Groundwater as the Largest Proportion of Freshwater:
Groundwater refers to the water present beneath the Earth's surface in the saturated zone of soil and rock. It is a significant source of freshwater and plays a crucial role in supporting various ecosystems and human activities. Here's why groundwater is the largest proportion of freshwater:
1. Vast Reservoir:
- Groundwater makes up a significant portion of the Earth's freshwater supply, estimated to be around 30.1% of the total freshwater volume.
- It exists in large underground aquifers, which can store vast amounts of water.
- These aquifers are formed over thousands of years as rainwater infiltrates through the soil and permeable rock layers.
2. Accessibility and Reliability:
- Groundwater is relatively more accessible and reliable compared to other freshwater sources.
- It can be accessed through wells and boreholes, providing a consistent water supply for drinking, irrigation, and industrial purposes.
- Even during droughts or dry seasons, groundwater can sustain rivers and wetlands, ensuring the survival of ecosystems.
3. Slow Replenishment:
- Unlike surface water sources such as lakes and rivers that depend on precipitation, groundwater is replenished through a slower process called recharge.
- Recharge occurs when precipitation seeps into the ground and reaches the water table, replenishing the aquifers.
- This slow replenishment rate makes groundwater a non-renewable resource in some regions, as it cannot be replenished at the same rate it is being extracted.
4. Global Distribution:
- Groundwater is found worldwide, and its distribution is influenced by various factors such as geology, climate, and topography.
- It can be found in varying quantities beneath different types of landscapes, including deserts, plains, and mountains.
- However, the availability and quality of groundwater differ across regions, highlighting the importance of sustainable management practices.
Other Freshwater Sources:
While groundwater constitutes the largest proportion of freshwater, it is important to understand the distribution of freshwater in other forms as well:
- Ice caps and glaciers: These are the largest reservoirs of freshwater on Earth, accounting for approximately 68.7% of the total freshwater volume. However, they are not directly accessible for human use.
- Freshwater lakes and rivers: This source accounts for about 0.3% of the total freshwater volume. While lakes and rivers provide important surface water resources, their volume is relatively smaller compared to groundwater.
- Atmosphere as moisture and clouds: The proportion of freshwater in the atmosphere is relatively minor, with estimates ranging from 0.001% to 0.04%. However, this moisture plays a crucial role in the water cycle and precipitation.
In conclusion, groundwater is the largest proportion of freshwater on Earth due to its vast reservoirs, accessibility, and global distribution. While ice caps and glaciers hold the majority of freshwater, they are not directly accessible. Understanding the distribution of freshwater sources is essential for sustainable water management and ensuring the availability of this vital resource for various needs.