The boundary surface is the water table which actually is a capillary fringe. Ground water moves slowly, except where it is trapped in basins. At great depth the lithostatic pressure closes the pores, and ends groundwater. Springs, ponds, lakes, and streams mark the surface intercepts of the water table. Permeability measure the rate of water passage through rocks, while porosity is a measure of open space in rock volume.
Springs are natural groundwater seeps or flows, formed where an aquiclude blocks water flow.
Wells are manmade. Pumping a well produces a cone of drawdown which must be considered in designing a well. Artesian springs and wells are formed in inclined strata, when water under pressure rises above the level of the confined aquifer.