Water Quality: Protecting Household Drinking Water
Module 3

Lesson 2- Glossary
Acknowledgement: Taken from "Living on the Land 2001"

Aerobic:  In the presence of or requiring oxygen.

Anaerobic (anoxic):  In the absence of oxygen.

Aquifer:  A sand, gravel, or rock formation capable of storing or conveying water below the surface of the land.

Bacteria:  Microscopic one-celled organisms which live everywhere and perform a variety of functions.  While decomposing organic matter in water, bacteria can greatly reduce the amount of oxygen in the water.

Best Management Practices (BMP):  Practices that have been determined to be the most effective, practical means of preventing or reducing water pollution from nonpoint sources

Biodegradable:  Capable of being broken down (decomposed) by microorganisms.

Coliform Bacteria:  A group of bacteria predominantly inhabiting the intestines of man or animal but also found in soil.  While harmless themselves, coliform bacteria are commonly used as indicators of the possible presence of pathogenic organisms.

Confined Aquifer:  Water-bearing formation with an upper boundary that is a layer that does not transmit water readily.

Conservation Tillage:  Any tillage and planting system that keeps at least 30 percent of the soil surface covered by residue after planting to reduce soil erosion by water.

Contaminant:  Any physical, chemical, biological, or radiological substance causing an impurity in the environment.

Decomposition:  Breaking down into component parts or basic elements.

Degradable:  Capable of being chemically reduced or broken down.

Denitrification:  Biochemical conversion of nitrate (NO₃) to N₂ gas under anaerobic conditions.

Drainage:  Downward movement of water through the soil.  When this happens quickly, the drainage is “good,” “fast,” or the soil is “well drained;” when it happens slowly, the drainage is said to be “slow,” “bad,” or soil is “poorly drained.”  Plant roots need oxygen as well as water, and soil that remains saturated deprives roots of necessary oxygen.

Drawdown:  Vertical drop of the water level in a well during pumping.

Effluent:  Discharge or emission of a liquid or gas.

EPA:  The United States Environmental Protection Agency.

Gray Water:  Wastewater other than sewage, such as sink or washing machine drainage.

Ground Water:  The subsurface water supply in the saturated zone below the water table.

Hydrologic Cycle:  The movement of water in and on the earth and atmosphere through processes such as precipitation, evaporation, runoff, and infiltration.

Infiltration:  Entry of water from precipitation, irrigation, or runoff into the soil profile.

Leaching:  The washing out or flushing of a soluble substance from an insoluble one.  In high-rainfall areas, rainwater leaches good as well as harmful substances from the soil.

Nonpoint Source (NPS):  Pollution from widespread or diffuse sources with no definite point of entry.  The source is not a readily discernible point such as a discharge pipe.

Nutrient:  That portion of any element or compound in the soil that can be readily absorbed and assimilated to nourish growing plants.

Pathogen:   Disease-causing biological agent such as a bacterium, virus, or fungus.

Percolation:  Movement of water through soil or rock.

Permeability:  Capacity of soil, sediment, or porous rock to transmit water.

Pollutant:  Any substance of such character and in such quantities that when it reaches a body of water, soil, or air, it is degrading in effect so as to impair its usefulness or render it offensive.

Recharge:  Downward movement of water through soil to ground water.

Recharge Area:  Land area over which precipitation infiltrates into soil and percolates downward to replenish an aquifer.

Runoff:  That portion of the precipitation or irrigation water which leaves property over the surface and appears in surface streams or water bodies.

Saturated zone:  Portion of the soil or rock profile in which all pores are filled with water.

Septic Tank:  Sewage disposal tank in which a continuous flow of waste material is decomposed by anaerobic (in the absence of oxygen) bacteria. 

Softening:  Process of removing hardness caused by calcium and magnesium minerals from water.

Soluble:  Capable of being dissolved easily.

Static Water Level:  Water level in a well before pumping.

Total Dissolved Solids (TDS):  Concentration of all substances dissolved in water (solids remaining after evaporation of a water sample).

Toxic:  Substances that even in small quantities may poison, cause injury, or cause death when eaten or ingested through the mouth and stomach, absorbed through the skin or inhaled into the lungs.

Unsaturated Zone:  Portion of the soil profile which contains both air and water.  Water in this zone cannot enter a well.

Watershed (Drainage Basin):   All land and water that drains runoff to a stream or other surface water body.

Water Table:  The upper level of a saturated zone in an aquifer below the soil surface.

Wellhead Protection:  The practice of preventing pollutants from seeping into wellwater at or near any active or abandoned well.

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