This map is part of an Idea Set called MapMaker: World Water Map.

MAP SUMMARY

Each year, the water cycle delivers water to regions through precipitation, rivers, and other water sources that replenish themselves. However, in some parts of the world, the human demand for water is greater than rivers, groundwater and shallow aquifers that get replenished can sustain. This difference between demand for water and that renewable water supply is known as the “water gap.” Water gaps are filled by draining deep groundwater reserves, which do not refill and are hard to access. By highlighting these gaps on a map, learners can see where humans are using more water than the water cycle can provide.

The Water Gap map includes layers that allows learners to examine:

• The projected 30-year change in water gap
• The average annual demand for water beyond the renewable supply
• How the water that accounts for that water gap is currently being used
• Locations of freshwater stories created by participants in the Freshwater Externship, a collaboration of National Geographic Society and The Nature Conservancy.

Learners will notice that as they zoom in on the map, the map becomes more detailed and shows smaller regions.

It is important to note that this map does not show regions where people have less access to water than they would like or do not have access to clean water for their needs. Some regions that have little or no water gap on this map use very little water because there is very little available water.

Teacher Tip: First introduce these layers to your students independently, then consider conclusions you can draw from the map as a whole. (For context, one cubic kilometer (km³) of water is equivalent to one trillion liters, or 400,000 Olympic-sized swimming pools.)

As you examine these layers, consider the following questions:

• Based on what you see in the maps, where are the gaps in the world? What do they use water for in these areas? What patterns do you see?
• What are steps people can take to reduce the highest level of demand for water in different regions of the world?
• What other information might you want to see on this map to learn more?

MAP LAYER
Water Gap: Average Annual Demand Beyond Renewable Supply

This layer focuses on the present state of the world’s water gap by highlighting regions where humans are using more water than the water cycle can provide. The layer delineates regions of the world in shades of yellow – the brighter the yellow indicated on the map, the larger the average annual gap between the water demand and the renewable water supply. This layer shows the average gap annual between 1989 and 2019.

How you can use this with your learners:

• Where do people use more water than the region’s rivers, groundwater or shallow aquifers provide?
• Identify a few regions where there is not a significant gap between the demand for water and the renewable supply. What does this mean?

MAP LAYER
Projected 30-Year Change in Water Gap

Thirty years from now, how much will the gap between demand and renewable supply of the world’s water have changed? This layer shows projections calculated for percent changes in future water gap. Scientists used a variety of data to predict how the average annual water gap will increase or decrease during the 30 years from 2020 to 2050.

• Regions with an arrow pointing up are regions where the gap is projected to increase in the next 30 years.
• Regions with a downward arrow are regions where the gap is projected to decrease in the next 30 years.

How you can use this with your learners:

• Identify a few areas where you see arrows pointing up indicating a projected increase in water gap. What do areas with large increases in water gap seem to have in common?
• Unclick the check box for all layers except for the 30-Year Projections. Then click the check box on for for the “Largest Source of Water Gap" layer. What patterns do you notice?
• Why might the gap be increasing more in certain regions than in others?

MAP LAYER
Largest Source of Water Gap

This layer illustrates how the water that accounts for the water gap is currently being used, whether for irrigation, domestic purposes or industry.

• Irrigation (in green): Water used to grow crops, including those eaten by humans and livestock
• Domestic (in blue): Water used in homes, including drinking water and lawn maintenance
• Industry (in pink): Water used in production of goods or energy
• Note: Regions with very low or no water gap appear gray.

Note: This layer is not displayed when the map is first opened. To show this layer, select "Map Layers" and select the check box.

How you can use this with your learners:

• Zoom into a region of the world of interest to you and click on the region to display a pop-up that includes a pie chart. How much does each type of water use contribute to the water gap in that region?

Note: The predominant use for gap and demand may not match depending on the water sources for each use.

MAP LAYER
Freshwater Stories

Pinpoints on both maps identify the locations of the stories told by participants in the Freshwater Externship, a collaboration of National Geographic Society and The Nature Conservancy.

These stories are the work of their authors and were not created by National Geographic Society or the Nature Conservancy. Maps may not reflect National Geographic Society map policy.

How you can use this with your learners:

• Select a point in an area of interest where an extern has created a StoryMap. Then click into the StoryMap and explore the story they are telling about that community.
  • What is this community experiencing in relation to water gap?
  • How has the water gap impacted the human and natural worlds?