Glossary of Water Well and Groundwater Terminology

Basic Concepts

• Abiotic –Non-living chemical and physical factors in the environment.
• Adsorption –The adhesion of molecules or particles to a surface.
• Aeration –The process of increasing the oxygen saturation of water.
• Alluvium –Sediment deposited by flowing water, often containing groundwater.
• Anisotropy –Variation in hydraulic conductivity in different directions within an aquifer.
• Coliform Bacteria –A group of bacteria commonly found in the environment, used as an indicator of water quality.
• Hydraulic Gradient –The slope of the water table or potentiometric surface, driving groundwater flow.
• Infiltration –The process by which water on the ground surface enters the soil.
• Isotropy –Uniformity in all orientations; opposite of anisotropy.
• Percolation –The downward movement of water through soil and rock.
• Runoff –Water that flows over the land surface and into streams and rivers.
• Seepage –Slow movement of water through soil or rock.
• Static Water Level –The static water level is the level of water in a well when the well is not being pumped.

Groundwater and Aquifers

• Aquiclude –A geological formation that does not transmit water.
• Aquitard –A less permeable layer that restricts the flow of groundwater from one aquifer to another.
• Artesian Pressure –The pressure that causes water in a confined aquifer to rise above the top of the aquifer.
• Artesian Well –An artesian well is one where water flows to the surface naturally due to pressure in the aquifer.
• Confined Aquifer –An aquifer that is bounded above and below by impermeable layers.
• Confining Layer –A layer of rock or sediment that restricts the flow of groundwater.
• Ephemeral Stream –A stream that flows only during or immediately after rainfall.
• Fissures –Cracks in rock formations that can store and transmit groundwater.
• Fractured Aquifer –An aquifer where groundwater moves through cracks and fractures in rock.
• Groundwater –Groundwater is water stored in the pores and fractures of underground rock formations.
• Groundwater Basin –A geographic area that contains a connected groundwater system.
• Groundwater Flow –The movement of groundwater through the pore spaces and fractures in rocks and sediments.
• Hydraulic Conductivity –Hydraulic conductivity is a measure of how easily water can move through porous materials and is crucial for determining well performance.
• Hydraulic Head –The total energy per unit weight of water, comprising elevation, pressure, and velocity heads.
• Hydrogeology –The study of groundwater and its interactions with geological formations.
• Impermeable Layer –A layer of material through which water cannot pass.
• Karst –A type of landscape formed from the dissolution of soluble rocks, often featuring sinkholes and underground streams.
• Lateral Flow –Groundwater movement parallel to the Earth's surface.
• Overdraft –Overdraft occurs when water is pumped from an aquifer faster than it is recharged.
• Perched Aquifer –A localized zone of saturation above the main water table, created by an impermeable layer.
• Potentiometric Surface –The level to which water in a confined aquifer would rise if unimpeded.
• Recharge –Groundwater recharge is the process where water from precipitation and other sources infiltrates the ground and replenishes aquifers.
• Recharge Area –A region where water infiltrates the ground and replenishes an aquifer.
• Unconfined Aquifer –An aquifer that is directly open to the surface and whose water table can rise and fall.
• Vadose Zone –The area between the ground surface and the water table, also known as the unsaturated zone.
• Water Table –The upper surface of the zone of saturation, where groundwater pressure is equal to atmospheric pressure.

Hydrogeological Processes

• Capillary Fringe –The subsurface layer where groundwater seeps up from a water table by capillary action.
• Catchment Area –The area from which rainfall flows into a river, lake, or reservoir.
• Geophysical Logging –The process of recording the physical properties of rocks and sediments in a borehole.
• Graben –A depressed block of land bordered by parallel faults, often filled with sediment.
• Lithology –The physical characteristics of rock or sediment.
• Macropore –A large soil pore that can transmit water rapidly.
• Piezometer –An instrument used to measure the pressure of groundwater at a specific point.
• Priming –The process of filling a pump with water to remove air and allow it to function.
• Tracer Test –The use of a dye or other substance to track the movement of groundwater.
• Transmissivity –The ability of an aquifer to transmit water, equal to the hydraulic conductivity times the saturated thickness of the aquifer.

Water Quality

• Chlorination –The process of adding chlorine to water to disinfect it.
• Dissolved Oxygen –The amount of oxygen dissolved in water, important for aquatic life.
• Effluent –Wastewater discharged into the environment from a treatment plant or industrial process.
• Leachate –Contaminated water that has percolated through a landfill or other waste material.
• Methemoglobinemia –A condition caused by high nitrate levels in water, reducing the blood's ability to carry oxygen.
• pH Level –A measure of the acidity or alkalinity of water.
• TDS (Total Dissolved Solids) –A measure of all dissolved substances in water.
• Turbidity –A measure of the cloudiness or haziness of water, often caused by suspended particles.
• UV Disinfection –A method of water purification that uses ultraviolet light to kill microorganisms.
• Water Softener –A device that removes minerals, such as calcium and magnesium, from water to prevent scaling.

Water Treatment and Purification

• Backwashing –The process of reversing the flow of water to clean a well screen or filter.
• Chlorination –The process of adding chlorine to water to disinfect it.
• Reverse Osmosis –A water purification process that removes contaminants by using pressure to force water through a membrane.
• UV Disinfection –A method of water purification that uses ultraviolet light to kill microorganisms.
• Water Softener –A device that removes minerals, such as calcium and magnesium, from water to prevent scaling.

Water Well Equipment

• Air Lift Pump –A pump that uses compressed air to lift water from a well.
• Bailer –A device used to remove water or sediment from a well.
• Centrifugal Pump –A pump that uses a rotating impeller to increase the pressure and flow of water.
• Check Valve –A valve that allows water to flow in one direction only, preventing backflow.
• Discharge Pipe –The pipe through which water is discharged from a well or pump.
• Drop Pipe –The pipe that extends from the wellhead to the pump in a well.
• Electric Submersible Pump –A pump that is submerged in water and uses electricity to lift water from a well.
• Foot Valve –A valve at the bottom of a well pipe that prevents backflow and keeps the pump primed.
• Gravel Pack Screen –A screen placed in a gravel pack to prevent fine sediments from entering the well.
• Liner –A pipe inserted into a well to prevent collapse and improve water flow.
• Mud Rotary Drilling –A drilling method that uses drilling mud to lubricate the bit and remove cuttings.
• Packers –Devices used to isolate sections of a well for testing or treatment.
• Perforated Casing –A well casing with holes to allow water to enter.
• Pitless Adapter –A device that allows water to flow from a well to the surface without a hole in the casing above the frost line.
• Pressure Tank –A tank that maintains water pressure in a well system.
• Pump Curve –A graph showing a pump's performance characteristics, such as flow rate and head.
• Pump Jack –A mechanical device used to lift water from a well.
• Sand Point –A shallow well driven into sand or gravel.
• Solar Pump –A pump powered by solar energy.
• Static Head –The vertical distance between the water level in a well and the point of discharge.
• Submersible Pump –A pump placed underwater in a well to push water to the surface.
• Thief Pump –A small pump used to remove water from the bottom of a well.
• Tremie Pipe –A pipe used to place materials, such as grout, at the bottom of a well.
• Turbine Pump –A pump that uses a rotating impeller to lift water from a well.
• Vent Pipe –A pipe that allows air to enter and exit a well system to prevent vacuum or pressure buildup.
• Wellhead Protection Area –A designated area around a well to protect it from contaminants.

Well Construction and Components

• Annulus –The space between the well casing and the borehole wall.
• Borehole –A narrow, deep hole drilled into the ground to access groundwater.
• Casing Seal –Material used to seal the space between the well casing and the borehole wall.
• Clay Layer –A fine-grained, impermeable layer that can act as a confining layer for groundwater.
• Cone of Depression –A lowering of the water table around a pumping well.
• Drawdown –Drawdown is the difference between the static water level and the pumping water level.
• Gravel Pack –Gravel placed around a well screen to prevent fine sediments from entering the well.
• Jet Pumps –Jet pumps are used for shallow wells and are mounted above the ground.
• Liner –A pipe inserted into a well to prevent collapse and improve water flow.
• Mud Rotary Drilling –A drilling method that uses drilling mud to lubricate the bit and remove cuttings.
• Packers –Devices used to isolate sections of a well for testing or treatment.
• Perforated Casing –A well casing with holes to allow water to enter.
• Pitless Adapter –A device that allows water to flow from a well to the surface without a hole in the casing above the frost line.
• Screen Slot Size –The size of the openings in a well screen, determining what size particles are filtered out.
• Well Cap –A cover placed on top of a well casing to prevent contamination.
• Well Depth –The total depth of a well from the surface to the bottom.
• Well Log –A detailed record of the geological formations encountered during drilling and the construction details of a well.
• Well Screen –A well screen is a filtering device at the bottom of the well that allows water to enter while keeping out sand and gravel.

Well Maintenance and Testing

• Backwashing –The process of reversing the flow of water to clean a well screen or filter.
• Bailer –A device used to remove water or sediment from a well.
• Borehole Camera –A camera used to inspect the inside of a borehole or well.
• Drawdown Cone –A cone-shaped depression in the water table around a pumping well.
• Flow Meter –A device used to measure the flow rate of water.
• Hydrofracturing –A process of injecting water at high pressure to increase the flow of groundwater to a well.
• Jetting –The process of using high-pressure water to clean or develop a well.
• Monitoring Well –A well used to observe groundwater levels and quality.
• Pump Test –A test to determine the capacity and performance of a well and pump.
• Slug Test –A method to determine the hydraulic conductivity of an aquifer by adding or removing a known volume of water in a well.
• Specific Capacity –The rate of water flow from a well per unit of drawdown.
• Specific Yield –The ratio of the volume of water that drains from a saturated material due to gravity to the total volume of the material.
• Test Hole –A small-diameter hole drilled to obtain information about subsurface conditions.
• Well Development –The process of removing fine sediments and drilling mud from a well to improve water flow.
• Well Rehabilitation –The process of restoring a well's flow and water quality, often through cleaning and repairs.
• Yield Test –A test to measure the amount of water a well can produce.