The Water Cycle (Poster, PDF)
This 26x38-inch poster, released in 2022, depicts the global water cycle. It shows how human water use affects where water is stored, how it moves, and how clean it is. This diagram is available in English and Spanish. For each language, the diagram is available as an image (PNG), as a 26x38-inch poster (PDF), as a 8.5x11-inch handout (PDF), and as a 8.5x11-inch fill-in-the-blank worksheet (PDF). A comprehensive text description of the diagram is also available.
Visit the USGS Water Science School for definitions and more information about the water cycle.
The diagram was created by the USGS VizLab, in collaboration with the USGS Water Resources Mission Area Web Communications Branch, for the USGS Water Science School.
The water cycle describes where water is found on Earth and how it moves. Water can be stored in the atmosphere, on Earth’s surface, or below the ground. It can be in a liquid, solid, or gaseous state. Water moves between the places it is stored at large scales and at very small scales. Water moves naturally and because of human interaction, both of which affect where water is stored, how it moves, and how clean it is.
Liquid water can be fresh, saline (salty), or a mix (brackish). Ninety-six percent of all water is saline and stored in oceans. Places like the ocean, where water is stored, are called pools. On land, saline water is stored in saline lakes, whereas fresh water is stored in liquid form in freshwater lakes, artificial reservoirs, rivers, wetlands, and in soil as soil moisture. Deeper underground, liquid water is stored as groundwater in aquifers, within the cracks and pores of rock. The solid, frozen form of water is stored in ice sheets, glaciers, and snowpack at high elevations or near the Earth’s poles. Frozen water is also found in the soil as permafrost. Water vapor, the gaseous form of water, is stored as atmospheric moisture over the ocean and land.
As it moves, water can transform into a liquid, a solid, or a gas. The different ways in which water moves between pools are known as fluxes. Circulation mixes water in the oceans and transports water vapor in the atmosphere. Water moves between the atmosphere and the Earth’s surface through evaporation, evapotranspiration, and precipitation. Water moves across the land surface through snowmelt, runoff, and streamflow. Through infiltration and groundwater recharge, water moves into the ground. When underground, groundwater flows within aquifers and can return to the surface through springs or from natural groundwater discharge into rivers and oceans.
Humans alter the water cycle. We redirect rivers, build dams to store water, and drain water from wetlands for development. We use water from rivers, lakes, reservoirs, and groundwater aquifers. We use that water (1) to supply our homes and communities; (2) for agricultural irrigation and grazing livestock; and (3) in industrial activities like thermoelectric power generation, mining, and aquaculture. The amount of available water depends on how much water is in each pool (water quantity). Water availability also depends on when and how fast water moves (water timing), how much water is used (water use), and how clean the water is (water quality).
Human activities affect water quality. In agricultural and urban areas, irrigation and precipitation wash fertilizers and pesticides into rivers and groundwater. Power plants and factories return heated and contaminated water to rivers. Runoff carries chemicals, sediment, and sewage into rivers and lakes. Downstream from these types of sources, contaminated water can cause harmful algal blooms, spread diseases, and harm habitats. Climate change is also affecting the water cycle. It affects water quality, quantity, timing, and use. Climate change is also causing ocean acidification, sea level rise, and extreme weather. Understanding these impacts can allow progress toward sustainable water use.