Aquifer: An underground layer of rock, sand or gravel that contains water in sufficient quantities to supply a well.

Artesian Well: A well that penetrates a confined aquifer. The water level in these wells rises above the upper surface of the aquifer due to pressure in the confined aquifer. If the water pressure is great enough, the well will overflow.

Condensation: The process whereby water is changed from a gas (water vapor) into a liquid.

Cone of Depression: The cone-shaped area around a well where the groundwater level is lowered by pumping. The shape of the cone is influenced by the underground porosity and water yield of the well.

Confined Aquifer: Aquifers that are wedged between layers of relatively impermeable materials and are consequently under pressure. Also known as an artesian aquifer.

Contaminant: Any physical, chemical, biological, or radiological substance or matter in the water.

Discharge Area: The area or zone where groundwater emerges from the aquifer. The outflow may be a stream, lake, spring, wetland, etc.

Evaporation: The process whereby water is changed from a liquid to a gas (water vapor).

TIP: DO NOT wash your car near your lawn where the soaps & other chemicals can percolate into the ground.

Groundwater: Water beneath the surface of the earth which saturates the pores and fractures of sand, gravel and rock formations.

Hardness: A characteristic of water caused by the presence of various salts, calcium, magnesium, and iron. Water is “soft” if the content of these materials is low. Water is “hard” if the content is high.

Hydrologic cycle: The continuous circulation of water between the earth and the atmosphere, involving condensation, precipitation, runoff, percolation, evaporation, and transpiration.

Non-point source pollution: Contaminates found in water from a source that cannot be specifically defined. For example contamination resulting from municipal runoff or agricultural infiltration.

Percolate: The downward flow of water through the pores or spaces of unsaturated rock or soil.

Permeability: The capacity of rock or salt to transmit water.

Plume: A flowing body of contaminated groundwater that extends from the source of contamination to another point in the direction of the groundwater flow.

Point source of pollution: Contaminants found in water that can be readily identified from a specific source such as a leaking underground storage tank.

Pollution: Any substance, natural or synthetic, that degrades water quality to such a degree that water is not suitable for a particular use.

Porosity: The degree to which the total volume of soil or rock is permeated with spaces or cavities through which water or air can move.

Potable Water: Water which is free from impurities that may cause disease or harmful physiological effects, such that the water is safe for human consumption.

Recharge Area: Areas of land that allow groundwater to be replenished through infiltration or seepage from precipitation or surface runoff.

Saturated Zone: The portion of subsurface soil and rock where every available space is filled with water. Aquifers are located in this zone.

Surface Water: Bodies of water, snow, or ice on the surface of the earth (such as lakes, streams, ponds, wetlands, etc.)

Transpiration: The process by which plants give off water vapor into the atmosphere.

Turbidity: A measure of water cloudiness caused by the amount of suspended matter in the water.

Unconfined Aquifer: An aquifer with the water table as its upper boundary. Because the aquifer is not under pressure the water level in a well is the same as the water table outside the well. An unconfined aquifer is near the earth’s surface causing it to be easily recharged as well as contaminated.

Watershed: All land and water within a drainage area, defined by topographic high points.

Water Table: The top of an unconfined aquifer where water pressure is equal to atmospheric pressure. The water table depth fluctuates with climate conditions on the land surface above and is usually gently curved and follows a subdued version of the land surface topography.

Well: An opening in the surface of the earth for the purpose of removing fresh water.