waiver A document that permits a system not to monitor.

wall-fired boilers Coal-fired furnaces in which burners are installed and fired on opposite walls of the unit.

warm front The leading edge of an advancing warm air mass that is replacing a retreating relatively colder air mass. Generally, with the passage of a warm front, the temperature and humidity increase, the pressure rises, and although the wind shifts (usually from the southwest to the northwest in the Northern Hemisphere) it is not as pronounced as with a cold frontal passage. Precipitation, in the form of rain, snow, or drizzle, is generally found ahead of the surface front, as well as convective showers and thunderstorms. Fog is common in the cold air ahead of the front. Although clearing usually occurs after passage, some conditions may produced fog in the warm air. See occluded front and cold front.

warning An announcement that is issued when severe weather 1) has developed; 2) is already occurring and reported; or 3) is detected on radar. Warnings state a particular hazard or imminent danger, such as tornadoes, severe thunderstorms, flash and river floods, hurricanes, etc

warrant (for arrest) A writ, directed to the marshal or other proper officer, requiring him to arrest the defendant or article named and bring him before the court or a magistrate.

waste Refuse from places of human or animal habitation; a solid, liquid, or gaseous by-product derived from human activities.

waste characterization Identification of chemical and microbiological constituents of waste material.

waste exchange Arrangement in which companies exchange their wastes for the benefit of both parties.

waste feed The continuous or intermittent flow of wastes into an incinerator.

waste load allocation The maximum load of pollutants each discharger of waste is allowed to release into a particular waterway. The portion of a stream’s total assimilative capacity assigned to an individual discharge or to a combination of point and nonpoint sources expressed as the total maximum daily load (TMDL).

waste minimization 1) Measures or techniques that reduce the amount of wastes generated during industrial production processes. 2) Recycling and other efforts to reduce the amount of waste going into the waste stream.

waste reduction Using source reduction, recycling, or composting to prevent or reduce waste generation.

waste stream The total flow of solid waste from homes, businesses, institutions, and manufacturing plants that are recycled, burned, or disposed of in landfills, or segments thereof such as the residential waste stream or the recyclable waste stream.

waste treatment lagoon A lined impoundment made by the excavation, or earth fill, to provide a long detention for biological treatment of wastewater.

waste treatment stream The continuous movement of waste from generator to treater and disposer.

wastewater The used water and solids from a community (including used water from industrial processes) that flow through a collection system to a treatment facility. Storm water, surface water, and groundwater infiltration also may be included in the wastewater that enters a wastewater treatment plant. The term “sewage” usually refers to household wastes, but this term is often replaced by the term “wastewater.”

wastewater infrastructure The plan or network for the collection, treatment, and disposal of sewage in a community.

wastewater treatment works A facility that receives influent wastewaters (and sometimes runoff accumulated in the collection system) from domestic and/or industrial sources and, by a combination of physical, chemical, and biological processes. Processes treats the wastewaters toremove or convert pollutants to produce an effluent that will not violate water quality standards or endanger public health when discharged. Also known by the acronyms WWTP (wastewater treatment plant), STP (sewage treatment plant), and POTW (publicly owned treatment works).

wastewater-treatment return flow Water returned to the hydrologic system by wastewater-treatment facilities.

waterborne disease outbreak The significant occurrence of acute infectious illness, epidemiologically associated with the ingestion of water from a public water system that is deficient in treatment, as determined by the appropriate local or state agency, being either the Commissioner or the state epidemiologist.

water budget 1) A summation of inputs, outputs, and net changes to a particular water resource system over a fixed period. Also, water balance model. 2) A method of assessing the size of future water resources in an aquifer, catchment area, or geographical region that involves evaluating all the sources of supply or recharge in comparison to all known discharges or abstractions.

water equivalent of snow Amount of water that would be obtained if the snow were completely melted.

water hammer A pressure wave within a closed pipeline that sounds like someone hammering on a pipe that occurs due to velocity changes as in the case when a valve is opened or closed very rapidly. When a valve position is changed quickly, the water pressure in a pipe will increase and decrease back and forth very quickly. This rise and fall in pressures can do serious damage to the system.

water outlet A discharge opening through which water is supplied to a fixture, into the atmosphere (except into an open tank that is part of the water supply system), to a boiler or heating system, to any device or equipment requiring water to operate but that are not part of the plumbing system.

water pollution The presence of enough harmful or objectionable material in water to damage the water’s quality.

water purveyor An agency or person that supplies water (usually potable water); an owner.

water quality criteria Levels of water quality expected to render a body of water suitable for its designated use. Criteria are based on specific levels of pollutants that would make the water harmful if used for drinking, swimming, farming, fish production, or industrial processes.

water quality-based limitations Effluent limitations applied to dischargers when mere technology-based limitations would cause violations of water quality standards. Usually applied to small discharges into streams.

water quality-based permit A permit with an effluent limit more stringent than one based on technology performance. Such limits may be necessary to protect the designated use of receiving waters.

water quality standards State-adopted and EPA-approved ambient standards for water bodies. The standards prescribe the use of the water body and establish the water quality criteria that must be met to protect designated uses.

water-resources region A USGS designated natural drainage basin or hydrologic area that contains either the drainage area of a major river or the combined drainage areas of two or more rivers; of 21 regions, 18 are in the conterminous United States, and one each are in Alaska, Hawaii, and the Caribbean.

water-resources subregion The 21 designated water-resources regions of the United States are subdivided into 222 subregions. Each subregion includes that area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin(s), or a group of streams forming a coastal drainage system. See water-resource region.

water reuse Using wastewater or reclaimed water from one application for another application. The deliberate use of reclaimed water or wastewater must be in compliance with applicable rules for a beneficial purpose (landscape irrigation, agricultural irrigation, aesthetic uses, ground water recharge, industrial uses, and fire protection).

water right A property right or legal claim to withdraw a specified amount of water in a specified time frame for a beneficial use.

watershed The land area that drains into a stream. An area of land that contributes runoff to one specific delivery point; large watersheds may be composed of several smaller “subsheds,” each of which contributes runoff to different locations that ultimately combine at a common delivery point.

water solubility The maximum concentration of a chemical compound that can result when it is dissolved in water. If a substance is water soluable, it can readily disperse through the environment.

water storage pond An impound for liquid wastes, so designed as to either accomplish some degree of biochemical treatment of the wastes or to reduce peak flow rates through equalization.

water supplier A person who owns or operates a public water system.

water supply Water taken into a waterworks from wells, streams, springs, lakes and other bodies of surface water, natural or impounded, and the tributaries thereto, and all impounded groundwater but does not include any water above the point of intake of such waterworks.

water supply forecasting Predicting the total (spring and summer) streamflow from snowmelt and rain which occurs during snowmelt.

water supply main Any water supply pipeline that is part of a waterworks distribution system.

water supply system 1) The collection, treatment, storage, and distribution of potable water from source to consumer. 2) The water service pipe, the water distributing pipes, and the necessary connecting pipes, fittings, control valves, and all appurtances in or adjacent to the building or premises. The water supply system is part of the plumbing system.

water table The level below which the soil or rock is saturated with water. Iit is also the upper boundary of the saturated zone. At this level, the hydraulic pressure is equal to atmospheric pressure. Also used to refer to an aquifer that exists in unconfined conditions (e.g., a water table aquifer).

water transfer Artificial conveyance of water from one area to another.

water treatment lagoon An impound for liquid wastes, so designed as to accomplish some degree of biochemical treatment of the wastes.

water use 1) In a restrictive sense, the term refers to water that is actually used for a specific purpose, such as for domestic use, irrigation, or industrial processing. 2) More broadly, water use pertains to human's interaction with and influence on the hydrologic cycle, and includes elements such as water withdrawal, delivery, consumptive use, wastewater release, reclaimed wastewater, return flow, and instream use. See also offstream use and instream use.

water well An excavation where the intended use is for the location, acquisition, development, or artificial recharge of groundwater (excluding sandpoint wells).

water well completion report A report form published by the State Water Control Board entitled "Water Well Completion Report" which requests specific information pertaining to the ownership, driller, location, geological formations penetrated, water quantity and quality encountered, and construction of water wells. The form is to be completed by the well driller.

waterworks A system that serves piped water for drinking or domestic use to (i) the public, (ii) at least fifteen connections, or (iii) an average of twenty-five individuals for at least sixty days out of the year. The term “waterworks” shall include all structures, equipment and appurtenances used in the storage, collection, purification, treatment and distribution of pure water except the piping and fixtures inside the building where such water is delivered.

waterworks with a single service A waterworks which supplies drinking water to consumers via a single connection service line.

water year A 12-month period from October 1 to September 30 used by the USGS to report water surface data.

water yield The runoff from the drainage basin, including groundwater outflow that appears in the stream, plus groundwater outflow that bypasses the gaging station and leaves the basin underground, and minus groundwater inflow that moves into the drainage basin underground from adjacent drainage basins. Water yield is precipitation minus evapotranspiration.

watt A unit of power equal to one joule per second. The power of a current of one ampere flowing across a potential difference of one volt.

watthour (Wh) An electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electrical circuit steadily for one hour.

waybill A record that accompanies the shipment during transit.

weather The instantaneous or short-term state of the atmosphere.

weather-adjusted See weather normalization.

Weather Forecast Office (WFO) A local office of the National Weather Service that is responsible for weather forecasts and warnings over a multicounty area. The river forecasts (from which river warnings and statements are generated) for rivers in the WFO's county warning area are provided by one or more river forecast centers

weather normalization Water demand, revenues, or other variables adjusted to a normal weather year; also known as weather adjusted.

web-based training (WBT) A form of computer-based training in which the training material resides on web pages accessible through the World Wide Web. Typical media elements used are text and graphics. Other media such as animation, audio, and video can be used, but require more bandwidth and in some cases additional software. The terms on-line courses and web-based instruction are sometimes used interchangeably with WBT.

web-casting Communicating to multiple computers at the same time over Internet by "streaming" live audio and/or live video. Through compression and decompression of the signal, audio and video are experienced in real time over Internet.

web-site Related collection of web documents. The address for a web site (see URL) takes you to the initial page, or home page. From the home page you can go to all the other pages on the web site.

weighted composite sample

weight-loss method A direct corrosion monitoring method that measures the rate of corrosion by metallic weight loss from a pipe section (or coupon) that has been contacted with a water supply over a period of time.

weir 1) A wall or plate placed in an open channel and used to measure the flow of water. The depth of the flow over the weir (or a chart or conversion table may be used) can be used to calculate the flow rate. 2) A wall or obstruction used to control flow (from settling tanks and clarifiers) to assure uniform flow rate and avoid short-circuiting.

weir box

weir diameter Many circular clarifiers have a circular weir within the outside edge of the clarifier. All the water leaving the clarifier flows over this weir. The diameter of the weir is the length of a line from one edge of a weir to the opposite edge and passing through the center of the circle formed by the weir.

weir loading A guideline used to determine the length of weir needed on settling tanks and clarifiers in treatment plants. Used by operators to determine if weirs are hydraulically (flow) overloaded.

weir loading (gpm/ft) = flow (gpm)/Length of weir (ft)

weir, proportional A specially shaped weir in which the flow through the weir is directly proportional to the head.

well A bored, drilled, or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension and whose purpose is to reach underground water supplies or oil, or to store or bury fluids below ground.

well casing Materials, such as conrete, piping, metal, and stone, that line and support a well and prevent it from collapsing.

well field Area containing one or more wells that produces usuable amounts of water.

wellhead protection area A protected surface and subsurface zone surrounding a well or well field supplying a public water system to keep contaminants from reaching the well water.

well injection The subsurface emplacement of fluids into a well.

well monitoring The measurement, by on-site instrumentation or laboratory methods, of the quality of water in a well.

well plug A watertight and gas-tight seal installed in a bore hole or well to prevent movement of fluids.

wet chemistry Laboratory procedures used to analyze a sample of water using liquid chemical solutions (wet) instead of, or in addition to, laboratory instruments.

wetlands Any number of tidal and nontidal areas characterized by saturated or nearly saturated soils most of the year that form an interface between terrestrial (land-based) and aquatic environments; include freshwater marshes around ponds and channels (rivers and streams), brackish and salt marshes; other common names include swamps and bogs.

wet oxidation Any process in which substances are converted to a higher oxidation state in a water media, such as activated sludge, trickling filters, ponds, or digesters.

wet pond Pond for urban runoff management that is designed to detain urban runoff and always contains water.

wet well A subsurface chamber used to collect and store water or wastewater prior to pumping or transferring to additional treatment.

wholesale water Water purchased or sold for resale purposes.

wilderness A tract or region of land uncultivated and uninhabited by humans or unoccupied by human settlements.

wildlife Undomesticated animals.

wildlife enhancement Manipulation of wildlife regions to promote increases in the amount or quality of living animals.

wildlife habitat Suitable upland or wetland areas promoting survival or wildlife.

wildlife refuge An area designated for the protection of wild animals, within which hunting and fishing are either prohibited or strictly controlled.

wilting point The minimum quantity of water in a given soil necessary to maintain plant growth. When the quantity of moisture falls below this, the leaves begin to drop and shrivel up.

wind Wind is the motion of air relative to the surface of the earth.

wind roses A type of analysis that describes wind measurements graphically and tabularly as a combination of the cardinal direction that the wind was coming from and the average speed from that direction for a particular time interval.

windrow A type of composting process in which the compost mixture piles are mixed by turning on regular intervals.

windward The direction from which the wind is blowing. Also known as the upwind side of an object. It is the opposite of the downwind or leeward side.

winter kill Wildlife or vegetation dying from exposure to cold winter weather or fishes dying from suffocation under snow-covered ice.

wire-to-water efficiency The efficiency of a pump and motor together. Also called the overall efficiency.

withdrawal The process of taking water from a source and conveying it to a place for a particular type of use. See also offstream use and self-supplied water.

witness A person who will appear to present evidence as testimony in any proceeding in a lawsuit. An expert witness is one who is skilled in some art, science, trade, profession, or other human activity, and may give opinions while under oath. A fact witness may not express opinions while testifying.

wood-burning-stove pollution Air pollution caused by from wood-burning stoves.

woodland Areas dominated by small, scattered trees with little overlap of canopy branches; loosely, a small tract of closed forest.

wood treatment facility An industrial facility that preserves lumber and other wood products for outdoor use. The process employs chromated copper arsenate, a regulated hazardous material.

working cell bank (wcb) A quantity of cells derived from one or more ampules of the master cell bank and used to initiate the production batch.

working level (WL) A unit of measure for documenting exposure to radon decay products, the so-called daughters. One working level is equal to approximately 200 picocuries per liter.

working level month (WLM) A unit of measure used to determine cumulative exposure to radon.

worksheet A document on which an analyst records his analytical work and findings.

World Wide Web (WWW) A hypertext-based, distributed information system originally created by researchers at CERN, the European Laboratory for Particle Physics, to facilitate sharing research information. The Web presents the user with documents, called web pages, full of links to other documents or information systems. Selecting one of these links, the user can access more information about a particular topic. Web pages include text as well as multimedia (images, video, animation, sound). Servers are connected to the Internet to allow users to traverse (or "surf") the Web using a Web browser. In addition, many other resource formats such as Gopher are accessible by Web browsers.

writ An order of the court.