A Water Dictionary

What's an Acre Foot?

A Water Dictionary

A B C D E F G H I J K L M N O P Q R S T U V W XYZ

A
Acre-Foot: A volume of water that covers one acre to a depth of one foot. It is equivalent to 325,850 gallons or 43,560 cubic feet.
Anthracite: A very hard coal used in water filters to remove particles.
Aquifer: An underground formation of rock or sediment through which water filters slowly. Wells are often drilled into aquifers.

B
Backflow: A hydraulic condition caused by differences in pressure.
Best Management Practices: Techniques and practices that are accepted as the most effective and practical means to control pollutants or otherwise conserve water resources.
Backwash: The process of cleaning particulate matter out of the filter media by reversing the flow of water.
BMPs: Best Management Practices

C
Capital Costs: Costs of financing equipment and new construction. Capital costs are usually fixed, one-time expenses.
Carcinogen: A cancer causing organic chemical commonly found in products such gasoline, pesticides, and paint thinners.
Central Valley Project: A Federal Water Project designed to store and transport water from Northern California to Central and Southern California for both urban and agricultural purposes. Shasta Dam is often referred to as the "keystone" of the Central Valley Project (CVP).
Chorination: The process of adding chlorine to water, for the purpose of disinfection.
Cholera: An infectious disease of the small intestines whose bacteria is often found in untreated water.
Condensation: The process by which liquid is removed from a vapor mixture (such as clouds).
Conservation: The act of protecting or preserving a resource.
Contaminants: Any physical, chemical, biological, or radiological substance added to water which makes water impure.
Cryptosporidium: A protozoan parasite that infects the intestinal lining of both animals and humans; causes Cryptosporidiosis, an unpleasant but not dangerous disease to people with normal immune systems.

D
Detention Time: Average length of time a drop of water or suspended particle remains in a chamber.
Disinfectant: A chemical used to purify water from contamination.
DOHS: California Department of Health Services

E
Effluent: Water or other liquid flowing from a reservoir, body of water, or treatment plant.
EPA: The U.S. Environmental Protection Agency
Evaporation: The process of drawing moisture from a substance.

F
Filtration: The process of removing impurities from water by passing it through layers of anthracite (coal), sand and gravel.
Floc: Collection of smaller particles that have come together into larger particles.
Flocculation: Part of the water treatment process.

G
GPD: Gallons per day, a measure of flow, over time.
Grey Water: Wastewater other than sewage, such as sink, shower, or washing machine drainage.
Groundwater, Ground Water: Water which ocurrs beneath the earth's surface.
Groundwater Basin: A geologic formation capable of storing a significant groundwater supply.

H
Hydrant: A device connected to a water main that provides water for fighting fires.
Hydrologic Cycle: The natural process of evaporation, condensation, and precipitation by which water is renewed and reused. Also known as the water cycle.
Hydrology: The study of the occurrence, distribution, circulation, and characteristics of natural waters of the earth.

I
Influent: Water or other liquid flowing into a reservoir, body of water, or treatment plant.
Inorganic: Describes material that is of mineral rather than plant or animal origin. Does not contain carbon and hydrogen.

J
Jar Test: Laboratory procedure for evaluating treatment plant chemical dosages.

K
Kinetic Energy: Energy possessed by a moving body of matter, such as water, as a result of its' motion.

L
Langlier Index: Used to indicate the corrosiveness of water.
Loading Rate: The flow rate per unit area (gpm/f) of a filter unit at which the water is passed through them.

M
Maximum Contaminant Level: The highest level of a contaminant permissible in water in a public water system.
MCL: See Maximum Contaminant Level.
MG/L: See Milligrams Per Liter.
MGD: Million gallons per day, a measure of flow.
Milligrams Per Liter: The weight of a chemical dissolved in a volume of water. A concentration of 1 mg/l means that one milligram of a chemical is dissolved in each liter (approximately 1 quart) of water. Commonly referred to as parts per million, or ppm.
MTBE: See Methyl Tertiary Butyl Ether.
Methyl Tertiary Butyl Ether: A chemical which adds oxygen to gasoline and which reduces harmful emissions in a vehicles's exhaust. Under consideration for regulation by the EPA as a water contaminant.

N
Non-Potable: Describes water that may contain contaminants and is considered unsafe for drinking.
NTU: Nephelometric turbidity unit - amount of turbidity (cloudiness) in a water sample.

O
Operations and Maintenance Costs: Ongoing expenses (e.g. repair costs, salaries) necessary to operate and maintain water facilities or components of the water supply system.
Organic: Describes material that originates from plant or animal sources and which contains carbon and hydrogen.

P
Parts Per Billion: A measure of concentration of a dissolved substance. Also known as ppb.
Parts Per Million: A measure of concentration of a dissolved substance. Also known as ppm.
Pathogen: A microorganism capable of causing disease; scientific name for GERM.
Percolation: The slow seepage of water into the ground.
Permeable: A property of material or soil that allows the movement of water through it.
Pollutant: Any substance that contaminates water.
Potable: Water which is considered safe for drinking.
PPB: See Parts Per Million
PPM: See Parts Per Billion
Precipitation: Atmospheric water vapor, such as rain or snow, that falls to earth.

Q
Quicklime: A substance used in water softening.

R
Recharge: Process by which water seeps or percolates into the groundwater basin either adding to or replacing that which has been removed.
Reservoir: A natural or man-made holding area used to store, regulate, or control water.
Runoff: That part of precipitation, snow melt, or irrigation water that is not absorbed by soil and which drains or flows off the land into streams or other surface waters.

S
Safe Drinking Water Act: An Act passed by Congress in 1976 which required the EPA to establish drinking water standards (including maximum contaminant levels) for public water suppliers and which requires public notification when those standards are not met.
Sedimentation: The process by which particles in water settle at the bottom of a basin or container.
Surface Water: All water naturally open to the atmosphere, including rivers, streams, lakes, and reservoirs.

T
TDS: See Total Dissolved Solids.
THM's: See Trihalomethanes.
Title 22: That portion of the California Administrative Code which requires that producers of drinking water regularly monitor their wells and other sources of supply for various chemical constituents.
Total Dissolved Solids: All of the dissolved solids in a sample of water, measured by evaporating the sample and weighing the residue.
Trihalomethanes: Collectively referred to as disinfection by-products; formed when chlorine reacts with decomposing plant material. The allowable amounts found in drinking water are regulated by the EPA.
Turbidity: A physical characteristic of water making the water appear cloudy.

U
Underdrain: The bottom part of a filter that collects the filtered water and uniformly distributes the backwash water.

V
Vacuum Breaker: A device that prevents backflow due to a siphoning action created by a partial vacuum that allows air into the piping system.
VOC: See Volatile Organic Compound.
Volatile Organic Compound: An organic chemical compound that has the ability to evaporate readily at normal temperatures. Includes various industrial solvents and degreasers such as TCE, PCE, and carbon tetrachloride.

W
Wastewater: The used water and solids that are the result of domestic or industrial uses of water. Includes municipal waste or sewage.
Water Meter: An instrument for measuring the amount of water used.
Water Purveyor: An agency or person that supplies water.
Water Supply System: A network of storage tanks and pipes designed for the distribution of potable water.
Water Table: The elevation or level of ground water. The upper surface of the saturated zone in an unconfined aquifer.
Watershed: The land area that drains into a stream or body of water.
Water Treatment: A process of cleaning water to make it suitable for drinking.
Well: A bored, drilled, or driven shaft, or a dug hole, whose purpose is to reach underground water supplies.

XYZ
Zeta Potential: A measurement of a particle charge strength surrounding suspended particulate matter (colloidal solids).