The quantity of water a formation yields depends on the thickness and what property of the formation?

The correct answer is permeability, which is a crucial property of a geological formation when considering how much water it can yield. Permeability refers to the ability of a material, such as soil or rock, to transmit fluids through its pores or fractures. High permeability allows water to flow more freely, enhancing the yield from a formation, while low permeability restricts water movement and reduces yield.

In contexts like aquifers or water supply formations, understanding permeability is essential because it directly affects the rate at which water can be extracted. Even if a formation is thick and has a significant volume of water, if it possesses low permeability, the flow rate to a well may be insufficient for practical use. This makes permeability a critical factor in assessing the water yield from any formation.

While porosity, density, and hydraulic conductivity are related concepts, they do not directly define the ease with which water can flow through a formation in the same way that permeability does. Porosity measures the volume of void space in a material but does not account for whether those voids are connected. Density provides information about the material's mass per unit volume but is not directly linked to hydraulic flow rates. Hydraulic conductivity, while related to permeability, encompasses both permeability and the fluid's viscosity and density