What is the meaning of storage factor Q?

The storage factor ( Q ) is a dimensionless quantity used in hydrogeology to describe the amount of water that can be stored or released from an aquifer per unit change in hydraulic head. It is defined as the product of the specific yield (for unconfined aquifers) or specific storage (for confined aquifers) and the thickness of the aquifer. A higher storage factor indicates a greater capacity for the aquifer to store water, influencing groundwater management and resource assessments.