Groundwater is water located beneath the earth's surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology.

Typically, groundwater is thought of as liquid water flowing through shallow aquifers, but technically it can also include soil moisture, permafrost (frozen soil), immobile water in very low permeability bedrock, and deep geothermal or oil formation water. Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of the Earth's subsurface contains some water, which may be mixed with other fluids in some instances. Groundwater may not be confined only to the Earth. The formation of some of the landforms observed on Mars may have been influenced by groundwater. There is also evidence that liquid water may also exist in the subsurface of Jupiter's moon Europa.

Dahr Jamail (born 1968) is an American journalist who is best known as one of the few unembedded journalists to report extensively from Iraq during the 2003 Iraq invasion. He spent eight months in Iraq, between 2003 to 2005, and presented his stories on his website, entitled Dahr Jamail's MidEast Dispatches. Jamail writes for the Inter Press Service news agency, among other outlets. He has been a frequent guest on Democracy Now!. Jamail is the recipient of the 2008 The Martha Gellhorn Prize for Journalism.

Jamail is a fourth generation Lebanese American, the son of Gerald Jamail, and grew up in Houston, Texas. He graduated from Texas A&M University and later moved to Alaska.

In October 2007, his first book, Beyond the Green Zone: Dispatches from an Unembedded Journalist in Occupied Iraq, was published by Haymarket Books. Jamail began his national speaking tour in October 2007 in New York City, where many turned out to hear him and independent journalist Jeremy Scahill discuss the Afghan and Iraq wars.