GEOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -Aquifers must be both permeable and porous and include such rock types as sandstone, conglomerate, fractured limestone and unconsolidated sand and gravel. Fractured volcanic rocks such as columnar basalts also make good aquifers.

Detailed explanation-3: -Clay is the most porous sediment but is the least permeable. Clay usually acts as an aquitard, impeding the flow of water. Gravel and sand are both porous and permeable, making them good aquifer materials. Gravel has the highest permeability.

Detailed explanation-4: -Sedimentary rocks such as sandstone and limestone are good aquifers.

Detailed explanation-5: -Permeability is a measure of the interconnectedness of pores. The connection between pore spaces allows groundwater to flow through the sediment or rock. The combination of water storage (porosity) and flow (permeability) makes a good aquifer-a rock unit or sediment that contains usable groundwater.