Final answer:
An aquifer is a saturated, porous, and permeable layer of sediment or rock below the water table that can store and transmit water. Good examples include sandstone and limestone. Aquifers are crucial for providing fresh water and require careful management to prevent depletion. The correct answer is option 3.
Step-by-step explanation:
An aquifer is a saturated, porous, and permeable sediment or rock layer below the water table. It is capable of storing and transmitting water efficiently within its pore spaces or fractures. The ability of an aquifer to transmit water, known as permeability, depends on the size and interconnectedness of its pore spaces. Good aquifers, like sandstone and limestone, allow for significant water flow due to their high permeability.
On the other hand, impervious rock layers, such as shale or unfractured igneous rocks, act as confining layers or aquitards that restrict water flow and help define the boundaries of an aquifer.
Groundwater within aquifers plays a vital role in supplying fresh water to streams, lakes, and wells. It is a critical resource for drinking water and agricultural irrigation, especially in arid regions. Efficient groundwater management is essential to prevent depletion of aquifers, ensuring a sustainable water supply for future generations. Aquifers are recharged through precipitation, surface water infiltration, and deliberate pumping, with wetlands serving as excellent recharge areas.