D

Desalinization-removal of salt from saline water to provide freshwater.
Discharge-volume of water passing by a given location within a given time period. Usually expressed in either cubic feet per second (cfs) or gallons per minute (gpm).
Clorination Unit

Disinfectant-a chemical (commonly chlorine or ozone) or process used to kill microorganisms such as bacteria, viruses and protozoa in water treatment plants.
Distribution system-the network of pipes leading from a treatment plant to customers' plumbing systems.
Drainage basin-land area where precipitation from surrounding high points runs off into streams, rivers, lakes. Also known as a “watershed”.
Drawdown-the local lowering of the water table around a pumping well.
Drought-a sustained period of under-average precipitation.

E

Effluent-treated water flowing from a sewage treatment plant; can be used for landscape watering and artificial recharge.
Evaporation- process of liquid water becoming water vapor. (If occurring from leaf surfaces, it is called transpiration.)
Evapotranspiration-the sum of evaporation and transpiration.

Filter-porous material through which a liquid or gas is passed in order to separate out suspended particulate matter. (FILTRATION-act of filtering.)
Finished Water

Finished water-pure treated water ready to be delivered to customers.
Flocculent/floc-material added to raw water to cause suspended particles to coagulate and settle out/precipitate prior to further treatment by filtration and disinfection.
Flood plain-relatively flat and normally dry land alongside water that is covered during a flood.
Flood stage-elevation at which overflow of the natural banks of a water course begins.
Fluid-continuous, amorphous state of matter in which molecules move freely past one another; has the tendency to assume the shape of its container.