A saturated geological unit which can yield water to the wells at a sufficient rate to support a well is called ______.

The correct answer is an aquifer.

• A saturated geological unit that can yield water to the wells at a sufficient rate to support a well is called an aquifer.

Key Points

• An aquifer is a body of porous rock or sediment saturated with groundwater. Groundwater enters an aquifer as precipitation seeps through the soil. It can move through the aquifer and resurface through springs and wells.
• There are two general types of aquifers: confined and unconfined.
  • Confined aquifers have a layer of impenetrable rock or clay above them, while unconfined aquifers lie below a permeable layer of soil.
• Many different types of sediments and rocks can form aquifers, including gravel, sandstone, conglomerates, and fractured limestone.
• A common misconception about aquifers is that they are underground rivers or lakes. While groundwater can seep into or out of aquifers due to their porous nature, it cannot move fast enough to flow like a river.

Important Points

• Karst:
  • ​Karst is a type of landscape where the dissolving of the bedrock has created sinkholes, sinking streams, caves, springs, and other characteristic features.
  • Karst is associated with soluble rock types such as limestone, marble, and gypsum.
• Estuary:
  • ​An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea.
• Reservoir:
  • ​A reservoir is most commonly an enlarged natural or artificial lake created using a dam to store freshwater.