The groundwater is shown as a giant underground pool.
Now, I don’t expect my baked goods to be geologically correct. I’m also a huge sci-fi fan and happily suspend disbelief in the face of all manner of geological fallacies.
The Groundwater Myth
The problem is that most people think these misrepresentations of groundwater are accurate:
It is common for people to believe the myth that all groundwater exists in underground pools and rivers.
This makes for exciting movies, like Journey to the Center of the Earth (original or remake), where people understand that there are no dinosaurs in the middle of the earth but think the underground rivers and lakes could be real.
This misunderstanding about how groundwater occurs has real repercussions:
- It affects how people think about water rights
- It affects how people think about water use and availability
- It supports the use of unscientific practices like water dowsing
How and where does groundwater really occur?
The reality of groundwater is much less exciting and dramatic: most groundwater occurs in the spaces or cracks in the soil, sand, or rocks in the ground below us.
This is a good groundwater diagram:
The bottom half of this image shows how groundwater can fill the spaces (pores) between sand, gravel, and other materials, and how it can flow through small cracks (fractures) in the bedrock.
The best basic groundwater video I’ve seen comes out of the King County (Washington) Groundwater Protection Program. It’s a great combination of cute animation, catchy tunes, and accurate science, not to mention a great example of effective science communication. Just try to watch the whole thing without singing along or tapping your toes!
Just to be clear, though: I’d still eat the cake.
Update 1/29/2011: Dan points out below that sometimes groundwater does occur in large open spaces or voids in the subsurface. This is true, but the issue is that many people mistakenly think this is true for all groundwater, which is not correct. Check out Dan’s good comment and visit the USGS karst aquifer web site for more information and photos.
Learn more about groundwater:
- What is ground water? — a basic introduction from the U.S. Geological Survey (USGS)
- Ground water and the rural homeowner — a good introductory pamphlet for well owners and for understanding groundwater supply wells from the USGS
- Basic ground-water hydrology — a more technical introduction to groundwater science from the USGS
- Introduction to the water cycle – flash animation by the U.S. Environmental Protection Agency
Thanks to the following for allowing their copyrighted media to be used for non-commercial purposes:
- Natural Resources Canada for use of its groundwater diagram.
- King County (Washington) Groundwater Protection Program and Leapingmedia for use of the Story of Groundwater.