Water levels generally will recover to normal when pumping ceases. Drawdown is the difference between the level of water standing in a well under non-pumping and pumping conditions. It is the difference between the static water level and the pumping water level. Groundwater recharge is water that enters the soil and eventually reaches the saturated zone. The rate groundwater travels is controlled by the type of material comprising an aquifer, the porosity of the material, the slope of the water table, and the degree to which existing pores are interconnected.
Hydraulic gradient is the slope of the water surface.
The hydraulic gradient indicates which direction groundwater will flow, and how rapidly. Perched water tables occur when a low permeability material, located above the water table, blocks or intercepts the downward flow of water from the land surface. Permeability is a property of porous soils indicating how rapidly water will be transmitted through soils toward the groundwater. Sand and gravel have high permeabilities while clay has low permeability. Porosity refers to the percentage of the formation that consists of open spaces or voids that could contain air or water.