Water Resources and Hydrologic Cycle

Earth's water exists in various forms, primarily in oceans and freshwater.

A large percentage of Earth's surface is covered by water.

A small percentage of Earth's water is freshwater, usable by humans.

Water constantly moves between Earth's systems (atmosphere, hydrosphere, geosphere, biosphere).

Water is used for various purposes, including everyday human activities.

The continuous movement of water within the Earth's system, including evaporation, precipitation, infiltration, runoff, and transpiration.

The process where liquid water turns into water vapor, usually due to heat.

Water released from clouds in the form of rain, snow, sleet, or hail.

Water flowing over the land surface into streams and rivers.

Water that contains low amounts of dissolved salts, suitable for consumption.

Oceans, ice caps, groundwater, lakes, rivers, and other water sources contain different amounts of water.

Oceans hold the largest amount of water on Earth.

Ice caps and glaciers contain a significant portion of freshwater.

A small percentage (10%) of Earth's freshwater is found in the atmosphere at any given time.

In drier climates, a larger portion of precipitation returns to the atmosphere compared to wetter climates.

Only a small portion (0.25%) of total freshwater is found on the Earth's surface.

A significant portion of Earth's freshwater is frozen (not readily usable).

Lakes hold the largest amount of readily available surface freshwater.

45% of Earth's surface is covered by river basins which are important freshwater sources.

A substantial amount of freshwater is held underground.

Freshwater can be categorized as renewable (continuously replenished) or non-renewable (limited and not readily replenished).