What does the convex shape of a sand lens represent in aquifers?

The convex shape of a sand lens in aquifers signifies the flow of water within that aquifer. In hydrogeology, the water typically flows from areas of higher pressure to areas of lower pressure, which is influenced by the configuration of the geological materials. Sand lenses, being more permeable than the surrounding materials such as clay or silt, allow water to move freely through them and can create a distinct shape that reflects the paths that groundwater takes as it accumulates and flows through the aquifer system.

This shape can give insights into the hydraulic gradients and how groundwater is distributed, often indicating areas of recharge and discharge. In this context, the convex shape does not merely represent the presence of water or the geological structure but rather highlights the dynamic nature of groundwater movement and the interaction between different layers within the aquifer system.