Point Source

Quaquaversal musings on the geosciences and public information.

Category: groundwater Page 2 of 3

Explore the Principal Aquifers Map for #GroundwaterAwarenessWeek

It’s National Groundwater Awareness Week! I’m taking the opportunity to share some groundwater online information resources that I like.

Ever wish you could easily and quickly find the major regional aquifers at a location? Do you know what principal aquifers are in your area? Explore the The National Atlas Principal Aquifers Map. This interactive online map displays the outcrops of the principal aquifers of the lower 48 states plus Hawaii, the U.S. Virgin Islands, and Puerto Rico.

Principal Aquifers of the lower 48 States

If you’ve never used the map, here are some features to try:

  • Zoom out to the 50 states
  • Zoom in to a particular state
  • Search for a location name.
  • Click on the “map key” tab to display an explanation of the color and the name of the associated aquifer system.
  • Click on the “identify” button and then on a location within one of the aquifers to bring up a description of the principal aquifer at that location and links to additional information.
  • Email or save a map.
  • Select the “print” option to bring up a map image that is perfect to save for web use.
  • Explore the other layers in the map. Select multiple layers to display them at the same time. (Don’t forget to click on “redraw map” to have your changes display on the map.)

What is an aquifer?

An aquifer is a geologic formation, group of formations, or part of a formation that contains sufficient saturated, permeable material to yield significant quantities of water to wells and springs.

Does the map show all aquifers?

This map only displays the shallowest of the the major regional aquifers (principal aquifers) present at a location in the United States. The map does not display all aquifers present at a location or all the aquifers in the country. If you want to use the map for scientific purposes, you should take a look at the metadata for the details about what is and is not included.


Want to do more than explore online? You can buy a paper copy of the map, which is perfect for office and classroom displays. You can download the GIS files to use locally. If you would like more detail about the map, the metadata explains the data sources and how the map was compiled.

References and Resources

Basic ground-water hydrology (USGS Water-Supply Paper 2220)

Ground Water Atlas of the United States (USGS Hydrologic Atlas 730)

Principal Aquifers of the 48 Conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands (USGS)

National Groundwater Awareness Week

Photo: well pump

(Image courtesy CDC)

When I was a child growing up in rural upstate New York, I passed the old green well pump in our yard multiple times a day.  Even though we didn’t use the hand pump, I knew that it stood over a groundwater well that provided all our water for drinking, preparing food, washing, irrigating the garden, and feeding the barn animals.

Most summers, the water took on a nasty odor, like rotten eggs. It stained fixtures. It made all the clothes washed in it smell bad. It tasted terrible. A few times a week we would drive to the nearby small town and fill up gallon jugs at a free municipal tap. We used this water for cooking and drinking. We hauled our laundry to a laundromat in town to avoid stains and smells.

For me, as a child, it was a minor nuisance. For my mother (responsible for the cooking, cleaning, and laundry), it meant that all the normal household tasks for our family were significantly more complicated and time consuming.

Groundwater Awareness

NGWA event logoBecause of these experiences, I learned about the importance of groundwater in my life at an early age. But these days, for many of us in the United States, groundwater is out of sight and out of mind. March 6 to 12, 2011, is National Ground Water Awareness Week, promoted by the National Ground Water Association and its many co-sponsors. It’s a good time to remind ourselves of the importance of groundwater for human health and the environment, and why we need to protect and conserve it.

Some Groundwater Facts

  • About 15% of people in the United States rely on their own private water supplies, which are not regulated under national water quality and health standards [Source: USEPA]
  • More than 1.5 billion people worldwide rely on groundwater for their drinking water [Source: USGS Circular 1308]
  • Nearly two-thirds of fresh groundwater withdrawals in the United States in 2005 were for irrigation. [Source: USGS Circular 1344]
  • Over 15.9 million water wells (of all types/purposes) serve the United States. [Source: NGWA]
  • In 2000, the High Plains aquifer provided 23% of the total U.S. withdrawals from all aquifers for irrigation, public-supply, and self-supplied industrial water uses combined [Source: USGS Circular 1279]

National Ground Water Awareness Week Links:

Page 2 of 3

All text and images copyright CBDawson unless otherwise specified.