Groundwater is water below the ground surface in the cracks and spaces in soil, sand, and rock. Groundwater is contained in formations known as aquifers, which consist of materials such as sand and gravel that are permeable (having large connected spaces between the materials that allow water to flow through). The area where water fills the aquifer is known as the saturated zone, and the top of this zone is known as the water table.
What is groundwater, and why it is important to protect it.