For an explanation, see the main splats page
The principles of groundwater
- Water that falls as rain soaks into the ground, and fills the spaces between the particles in soil and rock. This groundwater flows slowly to the sea or lakes.
- Groundwater occurs wherever the geology allows it to exist, provided there are surface supplies available to top it up as it seeps to the sea, or is taken out.
- The ground below a certain point is saturated with groundwater. The surface of this zone is called the water table. Wells fill to the level of the water table.
- Groundwater moves through an aquifer with a rate of flow that depends on the aquifer's permeability and the gravitational gradient that it is flowing down.
- Groundwater supplies are a strictly limited resource, but they can be recharged in some areas by disposing sensibly of stormwater into the aquifer.
- Around the world, many areas are taking groundwater out faster than the aquifer is being recharged by rainwater. Much of this water is being wasted.
- A cone of depression forms in the surface of the water table when water is drawn from a well faster than it is replaced by inflow or local recharging.
- Wars in the first half of the 21st century will mostly be about supplies of agricultural and potable water, both from dams and rivers, and also groundwater.
- At a spring, the water table reaches the surface, at a river or a lake, the water table also reaches the surface, instead of being somewhere below it.
- Around the world, many wells deliver dangerous amounts of arsenic and other dissolved minerals which are capable of causing serious health problems.
- When too many trees are cut down, rainwater can reach the water table faster than it flows away, so that the water table rises, sometimes to the surface.
- When a water table reaches the surface, it brings dissolved salt with it. Sometimes the salt is concentrated enough to kill plants, a process called salination.
This file is http://members.ozemail.com.au/~macinnis/scifun/, first created on February 20, 2009. Last recorded revision (well I get lazy and forget sometimes!) was on February 20, 2009.
©The author of this work is Peter Macinnis, who asserts his sole right to the product as it is packaged here, recognising that many of the ideas are common. You are free to use this as a model to do your own version. Copies of this whole file or site may be made and stored or printed for personal or educational use. You can contact me at firstname.lastname@example.org, but only if you add my first name to the front of that email address -- this is a low-tech way of making it harder to harvest the e-mail address I actually read.
This site had 219,000 hits on the index page from 1999 to January 2007 and an unknown number on other pages. In January 2007, a combined counter was placed on all of the pages, counting page hits which now total