Freshwater

While Earth has a lot of water, the vast majority of its freshwater is trapped in glaciers and ice caps. Only a small fraction is available as liquid water in rivers, lakes, or groundwater.

A watershed is the land area that channels rainfall and snowmelt to creeks, streams, and rivers. An aquifer is an underground layer of water-bearing rock.

Evaporation is the process where liquid water turns into water vapor (gas) due to heat. Condensation is the opposite, where gas turns into liquid.

Yellowstone sits atop a volcanic hotspot. The heat from the underlying molten rock (magma) warms the groundwater, creating the park's famous geysers and hot springs.

Development, agriculture, and invasive species all negatively impact the Everglades ecosystem. Preservation is a positive action intended to protect and restore the environment.

A divide is a high point or ridge of land that determines which direction water will flow into different watersheds. It acts as a boundary between drainage basins.

Clay and granite are both impermeable materials. Clay particles are packed too tightly for water to pass through, and solid granite lacks the interconnected pores needed for permeability.

The saturated zone is the area underground where all pores and fractures are completely filled with water. This water-bearing formation is known as an aquifer.

Groundwater is defined as water located beneath the Earth's surface in the spaces between soil particles and rock fractures.

Non-point source pollution comes from many diffuse sources, such as runoff from farms or city streets, making it difficult to trace to a single pipe or location.

A reservoir is a large natural or artificial lake used as a source of water supply. Humans build dams to create these for storage.

The water table is the upper boundary of the saturated zone, where the soil or rock below is completely filled with water.

The sun provides the thermal energy necessary to drive the water cycle by heating surface water, which causes evaporation.

Point source pollution is pollution that can be traced to a single, identifiable source, such as a pipe discharging waste from a factory.

Permeable materials have interconnected pores or cracks that allow water to flow through them easily. Impermeable materials block the flow of water.

A water shortage occurs when the demand for water resources exceeds the available supply in a specific area.

To extract groundwater, a well must be drilled deep enough to reach the saturated zone, which is the aquifer.

Wetlands act as natural filters by trapping sediments and absorbing pollutants from water as it flows through them, improving water quality.

Transpiration is the process by which plants release water vapor into the atmosphere through their leaves.

Precipitation is any form of water, liquid or solid, that falls from the atmosphere to the Earth's surface, including rain, snow, sleet, and hail.

The primary stages of the water cycle are evaporation, condensation, precipitation, and collection (or runoff/accumulation).

Condensation is the process where water vapor cools and turns back into liquid water droplets, which form clouds.

The total amount of water on Earth remains fairly constant because the water cycle continuously recycles the same water through different states and locations.

Wetlands act as natural sponges that soak up excess water during heavy rainfall. This process slows down water movement and reduces the peak flow of runoff, which helps prevent downstream flooding.

Approximately 97 percent of Earth's water is salt water found in oceans. Only about 3 percent is fresh water, and much of that is locked in glaciers or ice caps.