What is a freshwater lens aquifer?

• A. A freshwater layer located deep underground
• B. A layer of freshwater above saltwater, often near coasts
• C. A collection of freshwater lakes
• D. Groundwater in mountainous regions

Answer: (B)

A freshwater lens aquifer refers specifically to a layer of freshwater that is found above saltwater, which is commonly located in coastal areas. This occurs because of the hydrodynamic behavior of freshwater and saltwater, where freshwater is less dense than saltwater. When rainwater infiltrates the ground, it can create a freshwater lens that floats on top of the denser saltwater aquifer below. This lens can be crucial for supplying drinking water to coastal populations but is also susceptible to contamination, especially from seawater intrusion or over-extraction.

The context of this concept highlights its significance in environmental health, especially in areas where freshwater resources are limited or where there is pressure from development and natural resource extraction. Understanding the dynamics of a freshwater lens aquifer is essential for effective water resource management and sustainability in coastal regions.