Ground water is water that sinks beneath the soil and collects in aquifers, or holes and cracks in underground rock. Ground water does not stay underground forever. It eventually comes out in springs and drains into larger collecting basins. Ground water is a water supply for many people. Wells are built to bring water to the surface and many people rely on wells as a main source of water. Ground water is also used in farming to water large crops and livestock.
In some areas, people rely too heavily on ground water and there is not as much water available as there once was. Removing too much groundwater can cause salt water from nearby bodies of water to seep into the Earth and fill in the spaces where fresh water used to be. Salt water can’t be used in the same ways as fresh water so people are forced to find other fresh water sources.