Major Aquifers in Ohio

Ohio's aquifers can be divided into three major types of productive aquifers:

• Sand and Gravel Aquifers
• Sandstone Aquifers
• Carbonate Aquifers

The sand and gravel valley aquifers are distributed through the state. The valleys these sands fill are cut into sandstone and shale in the eastern half of the state and into carbonate aquifers in the western half of the state. The sandstone and carbonate aquifers generally provide sufficient production for water wells except where dominated by shale, as in southwest Ohio.

Piper Diagrams

The piper diagram provides a summary of cation data (left triangle), anion data (right triangle) and a composite diamond (center) to visually distinguish waters of different chemistries and origin. The small diamond points are the individual mean concentrations for each ambient station, and the squares are the average concentrations for the aquifer type.

BLUE POINTS: The carbonate ground waters in the piper diagram trend toward a more sulfate-rich composition, reflecting the dissolution of strontium- and calcium-bearing minerals. These waters display a wide range in alkalinity concentrations.

GREEN POINTS: The overlap between the carbonate and sand and gravel aquifer water chemistries is due to the fact that much of the aquifer material in the unconsolidated (sand and gravel) units is actually carbonate in origin.

RED POINTS: The sandstone water chemistry reveals a higher mean sodium, potassium, and chloride content than the other two systems, indicating a probable natural source for these ions, apparently from dissolution of simple salts or matrix cements.