Porosity: The amount of open space within a rock or sediment. Porous materials, like sandstone or gravel, have high porosity and can hold more water.
Permeability: The ability of a material to transmit fluids. Materials with high permeability allow water to flow through them easily, while those with low permeability hinder the flow of water.
Water Table: The upper surface of the zone of saturation, where the water fills all the spaces in the rock and sediment.