An aquifer is an underground layer of soil, sand, gravel or rock saturated with water. Water is held there in natural storage. Aquifers generally hold sufficient water to be used as a water supply. There are two basic types of aquifers in the Great Miami River Watershed:
Buried valley aquifers – a glacial deposit largely consisting of sand and gravel with water contained in the spaces.
Bedrock aquifers – a solid formation of rock lying beneath the surface of the soil containing enough water in its cracks and small spaces to provide water for wells.
The Great Miami River and some of its tributaries are located along the path of the buried valley aquifer. Most cities in the watershed depend on the high volume wells that are drilled into the permeable sand and gravel material of the buried valley aquifer for their drinking water.
Bedrock aquifers are the source of many private drinking water wells in the Great Miami River Watershed and generally produce enough water for residential home use.
