Visualizing Water – Slide 5

We can categorize our blue water use by major types of human activity. Irrigated agriculture withdraws and consumes the most blue water (both surface and groundwater), followed by electricity, domestic water supply, and industrial uses.
If we zoom in on each, we can see more detail on the relative amounts that they withdraw, return, and consume. In the case of agricultural irrigation, a total of 1,700 BCM of blue water is withdrawn from surface and groundwater sources. Of this water, nearly half is returned and more than half is consumed. That is, it evaporates from the soil or is transpired by plants.
In the case of electricity, about 1,471 BCM of blue water is withdrawn for cooling purposes in thermoelectric power plants, almost entirely from surface water. Almost all of this water is returned to rivers and lakes, though often at a higher temperature than when it was withdrawn.
In the case of domestic water supply used in our homes and businesses, a total of 563 BCM of water is withdrawn from rivers, lakes, and groundwater sources. Of this, about 20% is consumed through evaporation to the atmosphere. The rest—about 80%—is returned to rivers, lakes, and groundwater, typically with some level of increased pollution.
In the case of industrial uses, about 285 BCM of water is withdrawn from rivers, lakes, and groundwater. About 85% of this water is returned to these sources, though often with some level of pollution.