TERMS

The following are commonly used terms related to water law. Understanding the precise definition of each is an integral step in the process of law.

An abandoned well is a well that has not been used for six consecutive months.

An irrigation ditch or channel is an acequia, a term commonly used in San Antonio. These systems of water management, comprised of community irrigation ditches or canals, are rooted in ancient Spanish custom and many still operate in Texas and northern New Mexico.

An acre-foot (AF) is a unit commonly used for measuring the volume of water; equal to the quantity of water required to cover one acre (43,560 square feet or 4,047 square meters) to a depth of 1 foot (0.30 meter). This unit is equal to 43,560 cubic feet (1,234 cubic meters), or 325,851 gallons.

An affected person is any landowner within an area for which an application for a new or amended certificate of public convenience and necessity is filed; any retail public utility affected by any action of the regulatory authority; any person or corporation, whose utility service or rates are affected by any proceeding before the regulatory authority; or any person or corporation that is a competitor of a retail public utility with respect to any service performed by the retail public utility or that desires to enter into competition.

The affected public includes anyone who lives and/or works near a hazardous waste site or other source of pollutant emissions.

An affluent (stream) is a stream or river that flows into a larger one; it is also referred to as a Tributary.

Agricultural drainage is the process of directing excess water away from the root zones of plants by natural or artificial means, such as by using a system of pipes and drains placed below ground surface level. Subsurface Drainage is another name for agricultural drainage. Agricultural, or subsurface, drainage is also the name for the water that is drained away from the irrigated farmland.

The use of any tract of land for the production of animal or vegetable life is considered agricultural use; this includes, but is not limited to, the pasturing, grazing, and watering of livestock and the cropping, cultivation, and harvesting of plants.

Alkalinity refers to the extent to which water or soils contain soluble mineral salts. Waters with a pH greater than 7.4 are considered alkaline. The term is also used to quantify the capacity of water for neutralizing an acid solution. Alkalinity of natural waters is due primarily to the presence of hydroxides, bicarbonates, carbonates and occasionally borates, silicates and phosphates. It is expressed in units of milligrams per liter (mg/l) of CaCO3 (calcium carbonate). A solution having a pH below 4.5 contains no alkalinity.

Alternate concentration limits (ACLs) is one of the three types of standards that may be applied when a leak is detected at a treatment, storage, or disposal facility and groundwater compliance monitoring is required. ACLs are set by the U.S. Environmental Protection Agency (EPA) for specific hazardous waste constituents at levels that are designed to prevent a substantial hazard to human health or the environment. Groundwater compliance monitoring can use the following standards: (1) background concentrations, or the levels found in the area naturally; (2) specific values set by federal regulations in Title 40, Part 264.94, of the Code of Federal Regulations for eight metals and six pesticides and herbicides; or (3) alternative concentration limits.

The annual runoff is the total quantity of water in runoff for a drainage area for the year. Data reports may use any of the following units of measurement in presenting annual runoff data: (1) acre-feet (AC-FT, acre-ft, af)– the quantity of water required to cover 1 acre to a depth of 1 foot and is equal to 43,560 cubic feet, 325,851 gallons, or 1,234 cubic meters; (2) cubic feet per second per square mile (CFSM, (ft3/s)mi2) – the average number of cubic feet of water flowing per second from each square mile of area drained, assuming the runoff is distributed uniformly in time and area; (3) inch (In., in.) – the depth to which a drainage area would be covered with water if all the runoff for a given time period was uniformly distributed on it.

Aquifer Storage and Retrieval Project is a project with two phases that anticipates the use of a Class V aquifer storage well for injection into a geologic formation, group of formations, or part of a formation that is capable of underground storage of appropriated surface water for subsequent retrieval and beneficial use.

The process or series of operations by which an appropriative right is acquired is called appropriations. A completed appropriation thus results in an appropriative right; the water to which a completed appropriation in good standing relates is appropriated water.

Appropriated Water is a quantity of water from a well, stream, river, reservoir, or other source reserved for a specific use and place of use under state water-right laws, statutes, or regulations. It is also the name for surface water in an irrigation district that has been assigned or allocated to owners of water rights.

An aqueduct is a pipe, conduit, or channel designed to transport water from a remote source, usually by gravity. An aqueduct is also the name for a bridge-like structure supporting a conduit or canal passing over a river or low ground.

A geologic formation, a group of formations, or a part of a formation that is water bearing, stores or transmits water, or that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs is an aquifer. An underground layer of porous rock, sand, or gravel containing large amounts of water and capable of storing or conveying water below the surface of the land is also referred to as an aquifer.

Aquifer Storage and Recovery Project (ASR) consists of a project with two phases. ASR wells are used for storing water in the ground and recovering the stored water, from the same well, for a beneficial use. The aquifer essentially functions as a water bank. Deposits are made in times of surplus, typically during the rainy season, and withdrawals occur when available water falls short of demand.

An aquifer system is a body of permeable and relatively impermeable materials that functions regionally as a water yielding unit. It comprises two or more permeable units separated at least locally by confining units (Aquitards) that impede ground-water movement but do not greatly affect the regional hydraulic continuity of the system. The permeable materials can include both saturated and unsaturated sections.

The area surrounding a pumping or recharging well within which the water table or potentiometric surface has been changed due to the well’s pumping or recharge is known as the area of influence.

Artesian refers to the rising to the surface under internal hydrostatic pressure A commonly used expression, generally synonymous with Confined and referring to subsurface (ground) bodies of water which, due to underground drainage from higher elevations and confining layers of soil material above and below the water body result in underground water at pressures greater than atmospheric.

Artesian Aquifer also known as a confined aquifer. An artesian aquifer is an aquifer which is bounded above and below by formations of impermeable or relatively impermeable material containing artesian water.

A body of groundwater more or less compact, moving through soils with more or less resistance is called an artesian basin.

Artesian Pressure is ground water contained in aquifers between layers of permeable rock which is confined under pressure. If this aquifer is tapped into by a well, the water will rise above the top of the aquifer and may even flow from the well onto land. The pressure under which Artesian Water in an Artesian Aquifer is subjected to is significantly greater than atmospheric pressure.

Artesian Water is water that is collected from a drilled well into an aquifer. The water is confined by layers of clay and/or rock, once the well is drilled, the aquifer becomes pressurized and the water flows to the surface without the use of mechanical pumps.

Artesian Wells are from a confined aquifer (below the surface) containing groundwater that flows out of the well without the need of a pump. The name is derived from the French region of Artois, where the oldest well in Europe was bored in 1126. (2) A well tapping a Confined or Artesian Aquifer in which the static water level stands above the top of the aquifer. The term is sometimes used to include all wells tapping confined water. Wells with water levels above the unconfined water table are said to have positive artesian head (pressure) and those with water level below the unconfined water table, negative artesian head. If the water level in an artesian well stands above the land surface, the well is a Flowing Artesian Well. If the water level in the well stands above the water table, it indicates that the artesian water can and probably does discharge to the unconfined water body.

Artesian Zone is where water is confined within an aquifer under pressure so that the water will rise in the well casing or drilled hole above the bottom of the confining layer overlying the aquifer without pumping.

Available Water refers to the portion of water in the soil that can be absorbed by plant roots or used for growing crops.

Average Annual Recharge is the amount of water entering an aquifer on an average annual basis. In many, if not most, hydrologic conditions, “average” has little significance for planning purposes as there may exist so few “average” years in fact.

Backflow can consist of one of the following scenarios (1) the backing up of water through a conduit or channel in the direction opposite to normal flow. (2) the undesirable flow of water from a plumbing system back into the community potable water supply (3) a reverse flow condition created by a difference in water pressures that causes water to flow back into the distribution pipes of a drinking water supply from any source other than the intended one. Backflow prevention assemblies prevent contamination and are required by city and state laws. Backflow can also be referred to as Back Siphonage.

Backflow Preventer is a device which allows liquids to flow in only one direction through a pipe. Backflow preventers are used on sewer pipes to prevent a reverse flow during flooding situations. Also referred to as a Check Valve.

Base Flow is the portion of streamflow uninfluenced by recent rainfall or flood runoff and is comprised of springflow seepage and/or discharge from artesian wells or other groundwater sources, and the delayed drainage of large lakes and swamps. Base flow is characterized by loss flow regime (frequency, magnitude, and duration daily, seasonally, and yearly), by minimum low flow events and in context of the size and complexity of the stream and its channel.

Basin (1) (Hydrology) A geographic area drained by a single major stream; consists of a drainage system comprised of streams and often natural or man-made lakes. Also referred to as a Drainage Basin, Watershed, or Hydrographic Region. See Basins [Nevada]. (2) (Irrigation) A level plot or field, surrounded by dikes, which may be flood irrigated. (3) (Erosion Control) A catchment constructed to contain and slow runoff to permit the settling and collection of soil materials transported by overland and rill runoff flows. (4) (Nautical) A naturally or artificially enclosed harbor for small craft, such as a yacht basin.

Beneficial inflows require freshwater inflows which provide a salinity, nutrient, and sediment loading regime. This inflow is adequate and necessary to maintain an ecologically sound environment in the receiving bay and estuary that is necessary for the maintenance of productivity of economically important and ecologically characteristic sport or commercial fish and shellfish species and estuarine life upon which such fish and shellfish are dependent.

Beneficial Use (of Water) is the use of the amount of water which is economically necessary for a purpose authorized by law, when reasonable intelligence and reasonable diligence are used in applying the water to that purpose and shall include conserved water. Most states recognize the following uses as beneficial:

[1] domestic and municipal uses;
[2] industrial uses;
[3] irrigation;
[4] mining;
[5] hydroelectric power;
[6] navigation;
[7] recreation;
[8] stock raising;
[9] public parks;
[10] wildlife and game preserves.

Blackwater is water that contains animal, human, or food wastes; wastewater from toilet, latrine.

Blending consists of the mixing or combination of one water source with another, typically a finished source of water with raw water to reuse water while still satisfying water quality standards. For example, mixing of product water from a desalting plant with conventional water to obtain a desired dissolved solids content, or mixing brine effluents with sewage treatment plant effluents in order to reduce evaporation pond size.

Brackish is water having a somewhat salty taste, from containing a mixture of seawater and fresh water. Also see Brackish Water.

Brackish Water is water containing dissolved minerals in amounts that exceed normally acceptable standards for municipal, domestic, and irrigation uses. Considerably less saline than sea water. Also, Marine and Estuarine waters with Mixohaline salinity (0.5 to 30‰ due to ocean salts). Water containing between 1,000–4,000 parts per million (PPM) Total Dissolved Solids (TDS). The term brackish water is frequently interchangeable with Saline Water. The term should not be applied to inland waters.

Buffer Zone is (1) A protective, neutral area between distinct environments. (2) An area which acts to minimize the impact of pollutants on the environment or public parks;

Capital improvement plan is a plan which identifies capital improvements or facility expansions pursuant to which impact fees may be assessed.

Capital improvements includes water supply, treatment, and distribution facilities, wastewater collection and treatment facilities, stormwater, and drainage, and flood control facilities, including facility expansions, whether or not located within the service area, with a life expectancy of three or more years. The facility is owned and operated by or on behalf of a district with authorization to finance and construct such facilities, but such term does not include materials and devices for making connections to or measuring services provided by such facilities to district customers.

Capture is (1) Water withdrawn artificially from an aquifer is derived from a decrease in storage in the aquifer, a reduction in the previous discharge from the aquifer, an increase in the recharge, or a combination of these changes. The decrease in discharge from an aquifer plus the increase in recharge. Capture may occur in the form of decreases in the ground-water discharge into streams, lakes, and the ocean, or from decreases in that component of Evapotranspiration derived from the Zone of Saturation. (2) Diversion of the flow of water in the upper part of a stream by the headward growth of another stream.

Carrizo-Wilcox Aquifer is a major aquifer that extends across much of eastern Texas. It consists of the Wilcox Group and the overlying Carrizo Formation of the Clairborne Group. The aquifer is primarily com-posed of sand that is locally interbedded with gravel, silt, clay, and lignite deposited during the Tertiary Period. South of the Trinity River and north of the Colorado River, the Wilcox Group is divided into three distinct formations: the Hooper, Simsboro, and Calvert Bluff. Of the three, the Simsboro typically contains the most massive water-bearing sands. Carrizo Springs, located in Dimmitt County, used to flow continuously until 1929 when declining aquifer levels reduced the flow to intermittent. The groundwater, although hard, is generally fresh in the outcrop, whereas softer groundwater with higher total dissolved solids occurs in the subsurface. High iron and manganese content is characteristic of much of the aquifer, and localized saline contamination has affected portions of the aquifer in the Winter Garden area.

Casing is the steel conduit required to prevent waste and contamination of the ground water and to hold the formation open during the construction or use of the well. A tubular structure intended to be water tight installed in the excavated or drilled hole to maintain the well opening and, along with cementing, to confine the ground waters to their zones of origin and prevent the entrance of surface pollutants.

Certificate of Adjudication is an instrument evidencing a water right issued to each person adjudicated a water right in conformity with the provisions of Texas Water Code, §11.323, or the final judgment and decree in State of Texas v. Hidalgo County Water Control and Improvement District No. 18, 443 S.W.2d 728 (Texas Civil Appeals - Corpus Christi 1969, writ ref. n.r.e.).

Certificate of Convenience and Necessity (“CCN”) is a certificate issued by the Texas Commission on Environmental Quality which authorizes a utility, a utility operated by an affected county, or a water supply or sewer service corporation to render retail water or sewer utility service directly or indirectly to the public in a defined geographic area. Such CCNs are certifications from the Commission that the present or future public convenience and necessity requires or will require an installation, operation, or extension.

CFS (Cubic Foot per Second) is a unit of discharge for measurement of flowing liquid equal to a flow of one cubic foot per second past a given section. A rate of flow equivalent to 448.83 gallons per minute. Also called Second-Foot. Also written as C.F.S. and cfs.

Chloramines are compounds containing nitrogen, hydrogen, and chlorine, formed by the reaction between hypochlorous acid (HOCl) and ammonia (NH3) and/or organic amines in water. The formation of chloramines in drinking water treatment extends the disinfecting power of chlorine. Also referred to as Combined Available Chlorine.

Chlorides are negative chlorine ions, Cl–, found naturally in some surface waters and groundwaters and in high concentrations in seawater. Higher-than-normal chloride concentrations in fresh water, due to sodium chloride (table salt) that is used on foods and present in body wastes, can indicate sewage pollution. The use of highway deicing salts can also introduce chlorides to surface water or groundwater. Elevated groundwater chlorides in drinking water wells near coastlines may indicate Saltwater Intrusion.

Chlorinated refers to the water quality and describes water or wastewater that has been treated with either chlorine gas or a chlorine-containing compound.

Chlorine is one of a group of elements classified as the halogens. Chlorine, Cl2, the most common halogen, is a greenish yellow gas with an irritating odor. Chlorine is very reactive; it forms salts with metals, forms acids when dissolved in water, and combines readily with hydrocarbons. Various forms of chlorine are used to disinfect water. Chlorine is produced by the electrolysis of brine (a concentrated salt solution). Atomic number 17; atomic weight 35.45; freezing point –100.98EC; boiling point –34.6EC; specific gravity 1.56 (–33.6EC).

Clean Water Act (CWA) [Public Law 92–500] is more formally referred to as the Federal Water Pollution Control Act, the Clean Water Act constitutes the basic federal water pollution control statute for the United States. Originally based on the Water Quality Act of 1965 which began setting water quality standards. The 1966 amendments to this act increased federal government funding for sewage treatment plants. Additional 1972 amendments established a goal of zero toxic discharges and “fishable” and “swimmable” surface waters. Enforceable provisions of the CWA include technology based effluent standards for point sources of pollution, a state-run control program for nonpoint pollution sources, a construction grant program to build or upgrade municipal sewage treatment plants, a regulatory system for spills of oil and other hazardous wastes, and a Wetlands preservation program (Section 404).

Cone of Depression is the pumping from a well in a water table aquifer which lowers the water table near the well. This area is known as a cone of depression. The land area above a cone of depression is called the area of influence. Groundwater flows towards the well into the cone of depression. This can change the natural direction of groundwater flow within the area of influence around the well.

Connection is referred to as a single family residential unit or each commercial or industrial establishment to which drinking water is supplied from the system. It is a standardized measure of consumption, use, generation, or discharge attributable to an individual unit of development calculated in accordance with generally accepted engineering or planning standards. Connections shall be described in terms of single family equivalent connections, living unit equivalents, or other generally accepted unit typically attributable to a single family household. The assumed population equivalent per service unit shall be indicated. As an example, the number of service connections in an apartment complex would be equal to the number of individual apartment units. When enough data is not available to accurately determine the number of connections to be served or being served, the population served divided by three will be used as the number of connections for calculating system capacity requirements. Conversely, if only the number of connections is known, the connection total multiplied by three will be the number used for the population served.

Conservation is the practices, techniques, and technologies that will reduce the consumption of water, reduce the loss or waste of water, improve the efficiency in the use of water, or increase the recycling and reuse of water so that a water supply is made available for future or alternative uses.

Dam is any barrier, including one for flood detention, designed to impound liquid volumes and which has a dam height greater than six feet. This does not include highway, railroad, or other roadway embankments, including low water crossings that may temporarily detain floodwater, levees designed to prevent inundation by floodwater, closed dikes designed to temporarily impound liquids in the event of emergencies, or off-channel impoundments authorized by the TCEQ.

Discharge is the amount of water that leaves an aquifer by natural or artificial means.

Disinfectant is any oxidant, including but not limited to chlorine, chlorine dioxide, chloramines, and ozone added to the water in any part of the treatment or distribution process, that is intended to kill or inactivate pathogenic microorganisms.

Distribution system is a system of pipes that conveys potable water from a treatment plant to the consumers. The term includes pump stations, ground and elevated storage tanks, potable water mains, and potable water service lines and all associated valves, fittings, and meters, but excludes potable water customer service lines.

District is any district or authority created under Section 52, Article III, or Section 59, Article XVI, Texas Constitution, that has the authority to regulate the spacing of water wells, the production of water wells, or both.

Diversion is the removal of state water from a watercourse or impoundment.

Domestic use is the use of water by an individual or a household to support domestic activity. Such use may include water for drinking, washing, or culinary purposes; for irrigation of lawns, or of a family garden and/or orchard; for watering of domestic animals; and for water recreation including aquatic and wildlife enjoyment. If the water is diverted, it must be diverted solely through the efforts of the user. Domestic use does not include water used to support activities for which consideration is given or received or for which the product of the activity is sold.

Dam is any barrier, including one for flood detention, designed to impound liquid volumes and which has a height of dam greater than six feet. This does not include highway, railroad, or other roadway embankments, including low water crossings that may temporarily detain floodwater, levees designed to prevent inundation by floodwater, closed dikes designed to temporarily impound liquids in the event of emergencies, or off-channel impoundments authorized by the TCEQ.

Drawdown is the lowering of the ground water surface caused by withdrawal or pumping of water from a well. It is the difference between the static water level and the pumping water level in a well pumped at a constant flow rate.

Drinking water is all water distributed by any agency or individual, public or private, for the purpose of human consumption or which may be used in the preparation of foods or beverages or for the cleaning of any utensil or article used in the course of preparation or consumption of food or beverages for human beings. The term "Drinking Water" shall also include all water supplied for human consumption or used by any institution catering to the public.

Drought generally applies to periods of less than average or normal precipitation over a certain period of time sufficiently prolonged to cause a serious hydrological imbalance resulting in biological losses (impact flora and fauna ecosystems) and/or economic losses (affecting man). In a less precise sense, it can also signify nature’s failure to fulfill the water wants and needs of man. The following are three broad categories of drought:

[1] Meteorological Drought – Such a drought is considered to occur when annual rainfall (or precipitation) is less than the long-term average annual rainfall;
[2] Hydrological Drought – The onset of such a drought is signified by the occurrence and/or persistence of meteorological drought causing shortage of surface water in streams, lakes, reservoirs and/or groundwater supplies;
[3] Agricultural Drought – This type of drought occurs when soil moisture availability to agricultural crops is reduced to a level causing adverse effects on grain yield and consequently, the agricultural production of a region

Drought of record refers to the historic period of record for a watershed in which the lowest flows were known to have occurred based on naturalized streamflow.

Edwards Aquifer is the portion of an arcuate belt of porous, waterbearing, predominantly carbonate rocks known as the Edwards (Balcones Fault Zone) Aquifer trending from west to east to northeast in Kinney, Uvalde, Medina, Bexar, Comal, Hays, Travis, and Williamson Counties; and composed of the Salmon Peak Limestone, McKnight Formation, West Nueces Formation, Devil's River Limestone, Person Formation, Kainer Formation, Edwards Group, and Georgetown Formation. The permeable aquifer units generally overlie the less-permeable Glen Rose Formation to the south, overlie the less-permeable Comanche Peak and Walnut formations north of the Colorado River, and underlie the less-permeable Del Rio Clay region.

Domestic use is the use of water by an individual or a household to support domestic activity. Such use may include water for drinking, washing, or culinary purposes; for irrigation of lawns, or of a family garden and/or orchard; for watering of domestic animals; and for water recreation including aquatic and wildlife enjoyment. If the water is diverted, it must be diverted solely through the efforts of the user. Domestic use does not include water used to support activities for which consideration is given or received or for which the product of the activity is sold.

Effluent is both (1) something that flows out or forth, especially a stream flowing out of a body of water (2) (water quality) discharged wastewater such as the treated wastes from municipal sewage plants, brine wastewater from desalting operations, and coolant waters from a nuclear power plant.

Effluent Limitation is the amount or concentration of a water pollutant that can be legally discharged into a water body by a Point Source (PS), expressed as the maximum daily discharge, the maximum discharge per amount of product, and/or the concentration limit in the wastewater stream, as a 24–hour or 30–day average. The applicable technology-based standard is set by the U.S. Environmental Protection Agency (EPA) by Standard Industrial Classification (SIC) Code, but differs between new and existing sources and by broad types of water pollutants: conventional pollutants, toxic pollutants, nonconventional, nontoxic pollutants; dredge and fill wastes; and heat discharges.

Endangered Species Act (ESA) is an act passed by Congress in 1973 intended to protect species and subspecies of plants and animals that are of “aesthetic, ecological, educational, historical, recreational and scientific value.” It may also protect the listed species’ “critical habitat”, the geographic area occupied by, or essential to, the protected species. The U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) share authority to list endangered species, determine critical habitat and develop recovery plans for listed species. Currently, approximately 830 animals and 270 plants are listed as endangered or threatened nationwide at Title 50, Part 17, sections 11 and 12 of the Code of Federal Regulations. Further, under a settlement with environmental groups, USFWS has agreed to propose listing another 400 species over the next few years. The 1973 Endangered Species Act superseded and strengthened the Endangered Species Preservation Act of 1966 and the Endangered Species Conservation Act of 1969. The 1973 provisions required that the act be re-authorized by Congress every five years.

Environmental Assessment (EA) is an environmental analysis prepared pursuant to the National Environmental Policy Act (NEPA) that presents the first thorough examination of alternative plans to positively demonstrate that the environmental and social consequences of an applicable project or action were considered. If it is determined that proposed actions would not have a significant impact on the environment, then a Finding of No Significant Impact (FONSI) would be issued. If it is shown that such activities do, in fact, significantly impact the environment or are otherwise deemed controversial, then an Environmental Impact Statement (EIS) will normally be required.

Environmental Impact Statement (EIS) is a report required by Section 102(2)(c) of Public Law 91–190, National Environmental Policy Act (NEPA), for all major projects which significantly impact the quality of the human environment or are environmentally controversial. The EIS is a detailed and formal evaluation of the favorable and adverse environmental and social impacts of a proposed project and its alternatives. A tool for decision making, the EIS describes the positive and negative effects of an undertaking and cites possible, less environmentally disruptive alternative actions. Also see Environmental Assessment (EA).

Environmental Flows commonly refers to the amount of water needed in rivers, streams, and coastal areas to support fish and wildlife populations. Within this broader context, “instream flows” refer to the water needs of these populations in and along our surface waterways while “freshwater inflows” help maintain healthy and productive coastal bays and estuaries.

ESA (Endangered Species Act) refers to an act passed by Congress in 1973 intended to protect species and subspecies of plants and animals that are of “aesthetic, ecological, educational, historical, recreational and scientific value.” It may also protect the listed species’ “critical habitat”, the geographic area occupied by or essential to the species. The U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) share authority to list endangered species, determine critical habitat and develop recovery plans for listed species. As of July, 1993, nationwide, some 728 plants and animals were on the federal threatened or endangered list.

Estuary is (1) an area where fresh water meets salt water; for example, bays, mouths of rivers, salt marshes, and lagoons. (2) the portion of a coastal stream influenced by the tide of the body of water into which it flows, for example, a bay or mount of a river, where the tide meets the river current; an area where fresh and marine waters mix. The Coastal Zone Management Act of 1972 defines an estuary as “that part of a river or stream or other body of water having unimpaired connection with the open sea, where the sea-water is measurably diluted with freshwater derived from land drainage.” These brackish water ecosystems shelter and feed marine life, birds, and wildlife.

Facilities refers to all the plant and equipment of a retail public utility, including all tangible and intangible real and personal property without limitation, and any and all means and instrumentalities in any manner owned, operated, leased, licensed, used, controlled, furnished, or supplied for, by, or in connection with the business of any retail public utility.

Fault is a fracture in rock along which movement can be demonstrated. A fracture in the earth’s crust forming a boundary between rock masses that have shifted. Faults may be classified as follows:

[1] Active Fault – A fault that has moved recently and which is likely to move again, usually defined as one that has shown movement within the last 11,000 years and can be expected to move again within the next 100 years;
[2] Potentially Active Fault – A fault that moved within the Quaternary Period (i.e., within the last 2 million years) or a fault which, because it is judged to be capable of ground rupture or shaking, poses an unacceptable risk for a proposed project or structure;
[3] Historically Active Fault – A fault active within the last 200 years;
[4] Inactive Fault – A fault which has shown no evidence of movement in recent geologic time and no potential for movement in the relatively near future.

Fecal Coliform Bacteria is a group of bacteria normally present in large numbers in the intestinal tracts of humans and other warm-blooded animals. Specifically, the group includes all of the rod-shaped bacteria that are nonsporeforming, Gram-Negative, lactose-fermenting in 24 hours at 44.5EC, and which can grow with or without oxygen. In the laboratory, they are defined as all organisms that produce blue colonies with specified time frames. The presence of this type of bacteria in water, beverages, or food is usually taken to indicate that the material is contaminated with solid human waste. Bacteria included in this classification represent a subgroup of the larger group termed Coliform. Their concentrations are expressed as number of colonies per 100 mL of sample.

Fire Flow is the required flow rate of a water supply, generally measured at 20 psi (137.9 kPa) residual pressure that is available for fire fighting.

Firm Yield refers to the amount of water that the reservoir could have produced annually if it had been in place during the worst drought of record. In performing this simulation, naturalized streamflows will be modified as appropriate to account for the full exercise of upstream senior water rights is assumed as well as the passage of sufficient water to satisfy all downstream senior water rights valued at their full authorized amounts and conditions as well as the passage of flows needed to meet all applicable permit conditions relating to instream and freshwater inflow requirements. The dependable annual water supply that could be available in all years, without exceeding specified shortages in agricultural deliveries during droughts. Sometimes referred to as Dependable Yield.

Flood or Flood Waters describe the temporary inundation of normally dry land areas from the overflow of inland or tidal waters, or from the unusual and rapid accumulation or runoff of surface waters from any source. The rise in water may be caused by excessive rainfall, snowmelt, natural stream blockages, wind storms over a lake or any combination of such conditions. (2) An overflow of water onto lands that are used or usable by man and not normally covered by water. Floods have two essential characteristics: The inundation of land is temporary; and the land is adjacent to and inundated by overflow from a river, stream, lake, or ocean. (3) As defined, in part, in the Standard Flood Insurance Policy (SFIP): “A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waters or from the unusual and rapid accumulation or runoff of surface waters from any source.” (4) As defined under the National Flood Insurance Program (NFIP), a partial or complete inundation of normally dry land areas from (a) the overland flow of a lake, river, stream, ditch, etc.; (b) the unusual and rapid accumulation or runoff of surface waters; and (c) mudflows or the sudden collapse of shoreline land.

Flood according to (FEMA) is a general and temporary condition of partial or complete inundation or normally dry land areas from: (1) overflow of inland or tidal waters; (2) the unusual and rapid accumulation or runoff of surface waters from any source; (3) mudslides (i.e., mudflows) which are proximately caused by flood, as defined above, and are akin to a river of liquid and flowing mud on the surface of normally dry land areas, as when earth is carried by a current of water and deposited along the path of the current; and (4) the collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding the cyclical levels which result in flood, as defined above.

Facilities refers to all the plant and equipment of a retail public utility, including all tangible and intangible real and personal property without limitation, and any and all means and instrumentalities in any manner owned, operated, leased, licensed, used, controlled, furnished, or supplied for, by, or in connection with the business of any retail public utility.

Flood Damage is the direct and indirect economic loss caused by floods including damage by inundation, erosion, or sediment deposition. Indirect damages may also include emergency costs and business or financial losses. Evaluation may be based on the cost of replacing, repairing, or rehabilitating; or the comparative change in market or sales value; or on the change in income or production caused by flooding.

Flooding is the temporary inundation of all or part of the floodplain along a well-defined channel or temporary localized inundation occurring when surface water runoff moves via surface flow, swales, channels, and sewers toward well defined channels.

Flood Plain, and Floodplain according to FEMA is (1) any normally dry land area that is susceptible to being inundated by water from any natural source. This area is usually low land adjacent to a river, stream, watercourse, ocean or lake. (2) a strip of relatively smooth land bordering a stream, built of sediment carried by the stream and dropped in the slack water beyond the influence of the swiftest current. It is called a Living Flood Plain if it is overflowed in times of high water but a Fossil Flood Plain if it is beyond the reach of the highest flood. (3) the lowland that borders a stream or river, usually dry but subject to flooding. (4) the transversely level floor of the axial-stream drainageway of a semi-bolson or of a major desert stream valley that is occasionally or regularly alleviated by the stream overflowing its channel during flood. (5) the land adjacent to a channel at the elevation of the bankfull discharge, which is inundated on the average of about 2 out of 3 years. The floor of stream valleys, which can be inundated by small to very large floods. The one-in-100-year floodplain has a probability of 0.01 chance per year of being covered with water. (6) that land outside of a stream channel described by the perimeter of the Maximum Probable Flood. Also referred to as a Flood-Prone Area.

Flow is the movement of water and also refers to the rate of water discharged from a source given in volume with respect to time.

Flow Rate refers to the speed or rate at which water is taken from a water course or the speed at which it flows past a point, usually measured in gallons per hour or cubic feet per second (cfs). The rate, expressed in gallons or liters-per-hour, at which a fluid escapes from a hole or fissure in a tank. Such measurements are also made of liquid waste, effluent, and surface water movement.

Fluoridate (Fluoridation) is the process of adding a fluorine compound to a drinking water supply, for example, for the purpose of reducing tooth decay, particularly in children. Since 1962, the U.S. Public Health Service (PHS) has recommended an “optimal” fluoride concentration of 0.7 to 1.2 mg/l (milligrams per liter) to prevent dental caries and minimize mottling (fluorosis). In 1986, the U.S. Environmental Protection Agency (EPA) set the Maximum Contaminant Level (MCL) for fluoride at 4 mg/l.

Fluoride is a binary compound of Fluorine with another element; gaseous, solid, or dissolved compound containing fluorine that result from industrial processes. Fluoride combines with tooth enamel to render it less soluble in acid environments and fluoride compounds are added to public water supplies to prevent tooth decay. Excessive amounts in food can lead to Fluorosis. Fluorine is a halogen with the chemical symbol F.

Gallons per Minute is a unit expressing rate of discharge, used in measuring well capacity. Typically used for rates of flow less than a few cubic feet per second (cfs).

Gallons per Day (GPD) is a measure of the rate of flow or the rate of water withdrawal from a well. Typically used when the rate of flow in cubic feet per second (cfs) is too low to be useful.

Graywater (Gray Water or Greywater) is waste water from a household or small commercial establishment which specifically excludes water from a toilet, kitchen sink, dishwasher, or water used for washing diapers. In some cases gray water can be recycled for use in flushing toilets.

Groundwater is any water that is located beneath the surface of the ground and is not under the direct influence of surface water; specifically, the part that is in the saturated zone of a defined aquifer. The term also applies to water that flows or seeps downward and saturates soil or rock, supplying springs and wells. The upper level of the saturate zone is called the Water Table. Ground water lies under the surface in the ground’s Zone of Saturation, and is also referred to as Phreatic Water.

Groundwater Availability Model (GAM) is the process of developing and using computer programs to estimate future trends in the amount of water available in an aquifer and is based on hydrogeologic principles, actual aquifer measurements, and stakeholder guidance.

Groundwater Conservation District is any groundwater district created by the legislature or the commission subject to Texas Water Code, Chapter 36, to conserve, preserve, and protect the waters of a groundwater water reservoir.

Hazardous Material (EPA) is a substance, pollutant or contaminant listed as hazardous under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, and the regulations promulgated pursuant to that act.

Hazardous Substance refers to (1) any material that poses a threat to human health and/or the environment. Typical hazardous substances are toxic, corrosive, ignitable, explosive, or chemically reactive. (2) any substance designated by the U.S. Environmental Protection Agency (EPA) to be reported if a designated quantity of the substance is spilled in the waters of the United States or if otherwise released into the environment. Also referred to as Hazardous Waste.

Hazardous Waste is solid, liquid, or gaseous substances which because of their source or measurable characteristics, are classified under state or federal law as potentially dangerous and are subject to special handling, shipping, and disposal requirements.

Hepatitis A is a form of hepatitis caused by an RNA virus that does not persist in the blood serum and is transmitted by ingestion of infected food and water. The disease has a shorter incubation and generally milder symptoms than Hepatitis B. Also referred to as Infectious Hepatitis.

Hundred-Year Flood is the magnitude of a flood which has one chance in one hundred (i.e., one percent) of occurring in any one-year period. As the occurrence of floods is random in time, there is no guarantee that there will not be two one hundred-year floods within a given year, or that there will be one such flood within a given century (100 years). The boundary of the one hundred-year flood zone is used by the Federal Emergency Management Agency (FEMA) to designated Special Flood Hazard Areas. These areas are plotted on Flood Insurance Rate Maps (FIRMs), which are used in determining the flood risk to structures in the Flood Plain for flood insurance purposes.

Hydrilla is an exotic (nonnative) aquatic weed, hydrilla (Hydrilla verticillata) has come to represent a serious threat to lakes, reservoirs, streams and canals in the United States. A native of Asia, Africa, and Australia, hydrilla is part of a group of rooted aquatic plants well adapted to growth under water. Hydrilla was first introduced to the U.S. in Florida during the 1950s, probably for use in aquariums. Hydrilla is capable of prodigious growth, expanding from a few acres to several thousand acres in two to three years. Due to its ability to photosynthesize under very low light conditions, hydrilla becomes easily established in turbid waters and at greater depths than other aquatic plants. Most populations in the U.S. comprise dioecious female plants; reproduction is asexual, including fragmentation and the formation of hardy, long-lived propagules, called turions or tubers, which form deep in the sediment and remain viable for as long as ten years. Once hydrilla has invaded a site, the diversity of other rooted, submersed aquatic plants plummets, resulting in monospecific stands of hydrilla and loss of biodiversity. At its peak population, hydrilla has reduced water flows in canal systems by up to 80 percent and in small, standing-water impoundments, such as lakes and ponds, hydrilla can often completely cover the water surface within two to three years.

Hydrogeology is the part of geology concerned with the functions of water in modifying the earth, especially by erosion and deposition; geology of ground water, with particular emphasis on the chemistry and movement of water

Hydrologic pertaining to hydrology, is the science dealing with water, its properties, phenomena, and distribution over the earth’s surface.

Impact fee is a charge or assessment imposed by a water or wastewater utility against new development in order to generate revenue for funding or recouping the costs of capital improvements or facility expansions necessitated by and attributable to such new development. A charge or fee by a water utility for construction, installation, or inspection of a tap or connection to district water, wastewater, or drainage facilities, including all necessary service lines and meters, or for wholesale facilities that serve such water, sanitary sewer, or drainage facilities, shall not be deemed to be an impact fee if:

(A) it does not exceed three times the actual and reasonable costs to the water utility for such tap or connection;
(B) it is made to a nontaxable entity for retail or wholesale service, does not exceed the actual costs to the district for such work and for all facilities that are necessary to provide district services to such entity and that are financed or are to be financed in whole or in part by tax-supported or revenue bonds of the district; or
(C) it is made by a district for retail or wholesale service on land that at the time of platting was not being provided with water or wastewater service by the district.

Impervious Cover describes impermeable surfaces, such as pavement or rooftops, that prevent the infiltration of water into the soil. Rainwater collection systems for domestic water supplies are not considered impervious cover; Incapable of being penetrated by water; non-porous.

Impound is the accumulation and storage of water in a reservoir.

Impoundment is a body of water such as a pond, confined by a dam, dike, floodgate or other barrier. It is used to collect and store water for future use. It is, generally, an artificial collection and storage area for water or wastewater confined by a dam, dike, floodgate, or other barrier.

Industrial Use is the use of water for, or in connection with, commercial or industrial activities, including manufacturing, bottling; brewing; food processing; scientific research and technology; recycling; production of concrete, asphalt, and cement; commercial uses of water for tourism, entertainment, and hotel or motel lodging; generation of power other than hydroelectric; and other business activities.

Industrial Water Use (Withdrawals) is using water for industrial purposes such as fabricating, manufacturing, processing, washing, and cooling, and includes such industries as steel, chemical and allied products, paper and allied products, mining, and petroleum refining. The water can be obtained from a Public Water Supply System of may be self-supplied. The terms “water use” and “water withdrawals” are equivalent, but not the same as Consumptive Use as they do not account for return flows.

Inflow is the water that flows into an aquifer from another formation. Water, other than wastewater, that enters a sanitary sewer system (including sewer service connections) from sources such as roof leaders, cellar drains, yard drains, area drains, foundation drains, drains from springs and swampy areas, manhole covers, cross connections between storm sewers and sanitary sewers, catch basins, cooling towers, surface runoff, street wash waters, or drainage. Inflow does not include, and is distinguished from, Infiltration.

Injection generally refers to a system of artificially introducing surface water into the ground water system as a means of storage or recharge. Most typically, this includes the use of Recharge Wells which work directly opposite of pumping wells to inject surface water into underlying formations. Depending on the water-bearing formation, these methods may have limited usefulness and are generally better used for pumping water into deep, confined aquifers. Injection refers to a system of subsurface disposal of brine effluent into an acceptable formation. Also see Induced Recharge.

Injection Well refers to a well constructed for the purpose of injection treated wastewater directly into the ground Wastewater is generally forced (pumped) into the well for dispersal or storage into a designated aquifer. Injection wells are generally drilled into nonpotable aquifers, unused aquifers, or below freshwater levels.

Instream Flow is the amount of water remaining in a stream, without diversions, that is required to satisfy a particular aquatic environment or water use. It also describes the nonconsumptive water requirements which do not reduce the water supply; water flows for uses within a defined stream channel. Examples of instream flows include:

[1] Aesthetics — Water required for maintaining flowing steams, lakes, and bodies of water for visual enjoyment;
[2] Fish and Wildlife — Water required for fish and wildlife;
[3] Navigation — Water required to maintain minimum flow for waterborne commerce;
[4] Quality Dilution — Water required for diluting salt and pollution loading to acceptable concentrations; and
[5] Recreation — Water required for outdoor water recreation such as fishing, boating, water skiing, and swimming. Also referred to as Instream Use.

Instream Flow Requirement is the flow required in a stream to maintain desired instream benefits such as navigation, water quality, fish propagation, and recreation.

Instream Use refers to the beneficial use of instream flows for such purposes including, but not limited to, navigation, recreation, hydropower, fisheries, game preserves, stock raising, park purposes, aesthetics, water quality protection, aquatic and riparian wildlife habitat, freshwater inflows for bays and estuaries, and any other instream use recognized by law. An instream use is a beneficial use of water. Water necessary to protect instream uses for water quality, aquatic and riparian wildlife habitat, recreation, navigation, bays and estuaries, and other public purposes may be reserved from appropriation by the commission. Typically, non-consumptive uses of water that do not require diversion from its natural watercourse (e.g., fish and other aquatic life, recreation, navigation, esthetics, and scenic enjoyment). Also referred to as In-Channel Use, Nonwithdrawal Use, or Instream Flow.

Irrigation is the controlled application of water for agricultural purposes through man-made systems to supply water requirements not satisfied by rainfall; applying water to soil when rainfall is insufficient to maintain desirable soil moisture for plant growth.

Irrigation use is use of water for the irrigation of pastures and commercial crops, including orchards.

Interruptible, when referring to a groundwater withdrawal permit, is the conditioning of the right to withdraw groundwater from the Aquifer that makes the right subject to complete cessation, temporary curtailment, or reduction of the amount of groundwater that may be withdrawn from the Aquifer based upon the measurement of a water level at an index well.

Junior (Water) Rights is one who holds rights that are temporarily more recent than senior rights holders. All water rights are defined in relation to other users, and a water rights holder only acquires the right to use a specific quantity of water under specified conditions. Therefore, when limited water is available, junior rights are not met until all senior rights have been satisfied. See Prior Appropriation Doctrine.

Landfill is a disposal site which disposes of solid wastes on land. Wastes are deposited and compacted. At specific intervals, a layer of soil covers the waste and the process of deposit and compaction is repeated. The purpose is to confine the wastes to the smallest practical area and volume without creating nuisances or hazards to public health and safety, for example through leaching into the groundwater below the waste site.

Littoral Water Rights are the equivalent of Riparian Water Rights for a lake, reservoir, or other non-flowing body of water. As with riparian water rights, littoral water rights allow persons who own land adjacent to a body of water to make reasonable use of those waters on lands within the watershed. Littoral users share the waters among themselves and the concept of priority use (Prior Appropriation Doctrine) is not applicable. Under drought conditions, the lake or waterfront users also share shortages. Littoral rights cannot be sold or transferred to use on other (nonriparian) lands. Also see Riparian Doctrine.

A main is a relatively large pipe operated by a utility service provider that is used for transmission or distribution of water or to collect or transport sewage.

Maximum Contaminant Level (MCL) is the legally enforceable standard regulating the maximum allowed amount of certain chemicals in drinking water. MDLs must be met by the time water reaches an individual’s property. It is the designation given by the U.S. Environmental Protection Agency (EPA) to water quality standards promulgated under the Safe Drinking Water Act (SDWA) (Public Law 93–523). As prescribed by the EPA after research of a contaminant, the MCL is the greatest amount of a contaminant that can be present in drinking water without causing a risk to human health. MCLs are set for certain inorganic and organic chemicals, turbidity, coliform bacteria, and certain radioactive materials.

In the absence of verified historical data or in cases where a public water system has imposed mandatory water use restrictions within the past 36 months, Maximum Daily Demand means 2.4 times the average daily demand of the system.

MGD is an acronym that stands for million gallons per day. A unit of water usage used in many applications of water and wastewater treatment processes.

Microbe is short for Microorganism which is a small organism that can be seen only with the aid of a microscope. The term encompasses viruses, bacteria, yeast, molds, protozoa, and small algae; however, microbe is used most frequently to refer to bacteria. Microbes are important in the degradation and decomposition of organic materials added to the environment by natural and artificial mechanisms. Also referred to as Germs.

Million Gallons per Day (MGD) is a rate of flow of water equal to 133,680.56 cubic feet (cf) per day, or 1.5472 cubic feet per second (cfs), or 3.0689 acre-feet per day. A flow of one million gallons per day (mgd) for one year equals 1,120 acre-feet (365 million gallons).

Minimum Flow Appropriation is a term that refers to an appropriation designed to preserve a specified minimum flow in a stream. When the flow in the stream drops to that which is specified in the appropriation, junior appropriations will be required to stop diverting water in order to maintain the minimum flow. See (Prior) Appropriation Doctrine.

Minimum Instream Flow (Streamflow) is the specific amount of water required to support aquatic life, to minimize pollution, or for recreation. It is subject to the priority system and does not affect water rights established prior to its institution.

Mitigation describes actions designed to lessen or reduce adverse impacts; frequently used in the context of environmental assessment. Mitigation can include one or more of the following:

[1] avoiding impacts;
[2] minimizing impacts by limiting the degree or magnitude of an action;
[3] rectifying impacts by restoring, rehabilitating, or repairing the affected environment;
[4] reducing or eliminating impacts over time; and
[5] compensating for the impact by replacing or providing substitute resources or environments to offset the loss.

Municipal Discharge is the discharge of effluent from waste water treatment plants which receive waste water from households, commercial establishment, and industries. Combined sewer/separate storm overflows are included in this category.

Municipally owned utility is any retail public utility owned, operated, and controlled by a municipality or by a nonprofit corporation whose directors are appointed by one or more municipalities.

National Environmental Policy Act (NEPA) is a 1970 Act of Congress that requires all federal agencies to incorporate environmental considerations into their decision-making processes. The act requires an Environmental Impact Statement (EIS) for any “major federal action significantly affecting the quality of the human environment.”

Natural Flow is the rate of water movement past a specified point on a natural stream from a drainage area which has not been affected by stream diversion, storage, import, export, return flow or change in consumptive use resulting from man’s modification of land use. Natural flow rarely occurs in a developed country.

Navigable refers to a body of water that is capable of being navigated; deep enough and wide enough to afford passage to vessels. In the United States, for the purpose of defining the rights of ownership, some states have adopted the common-law test of flow of the tide, others that of actual navigability. For determining the right of the public to the use of a body of water as a public highway, however, the test in the U.S. is as to whether the water is navigable in fact or not. Waters are navigable in fact when they are used, or are susceptible of being used, in their ordinary condition as highways for commerce, over which trade and travel are or may be conducted in the customary modes of trade and travel on water.

Navigable Waters are those waters capable of supporting commerce. The waters of the United States, including the territorial seas, and intrastate waters, which is any body of water with any connection to interstate waters or commerce and this includes virtually all surface water and wetlands are considered navigable waters. Despite its name, there is no requirement for vessels to be able to navigate these waters. Provisions of the Clean Water Act (CWA) apply to all such waters, including wetlands.

NEPA — See National Environmental Policy Act (NEPA).

Nitrates represent a class of chemical compounds having the formula NO3 –. Nitrate salts are used as fertilizers to supply a nitrogen source for plant growth. Nitrate additions to surface waters can lead to excessive growth of aquatic plants. The presence of nitrates in groundwater occurs from the conversion of nitrogenous matter into nitrates by bacteria and represents the process whereby ammonia in wastewater, for example effluent discharges from septic tank systems, is oxidized to nitrite and then to nitrate by bacterial or chemical reactions. High groundwater nitrate levels can cause methemoglobinemia in infants.

Non-Aqueous-Phase Liquids (NAPLs) are organic chemicals (contaminants) that are immiscible with water. NAPLs are frequently toxic to many microorganisms used in Bioremediation. Such organic contaminants may be lighter than water (LNAPLs) or denser than water (DNAPLs). DNAPLs have proven to be one of the most difficult remediation problems to surmount and frequently constitute the more common pollutants found in water.

Non-Consumptive Water Use includes water withdrawn for use that is not consumed, for example, water withdrawn for purposes such as hydropower generation. This also includes uses such as boating or fishing where the water is still available for other uses at the same site. The terms Consumptive Use and Nonconsumptive Use are traditionally associated with water rights and water use studies, but they are not completely definitive. No typical consumptive use is 100 percent efficient; there is always some return flow associated with such use either in the form of a return to surface flows or as a ground water recharge. Nor are typically nonconsumptive uses of water entirely nonconsumptive. There are evaporation losses, for instance, associated with maintaining a reservoir at a specified elevation to support fish, recreation, or hydro-power, and there are conveyance losses associated with maintaining a minimum streamflow in a river, canal, or ditch.

Non-Point Source (NPS) Pollution refers to pollution discharged over a wide land area, not from one specific location. Water pollution caused by diffuse sources with no discernible distinct point of source, often referred to as runoff or polluted runoff from agriculture, urban areas, mining, construction sites and other sites. These are forms of diffuse pollution caused by sediment, nutrients, organic and toxic substances originating from land use activities, which are carried to lakes and streams by surface runoff. Technically, non-point source pollution, also referred to as Non-Point Water Pollution, means any water contamination that does not originate from a “point source,” which is designated in the Clean Water Act (CWA) as pollution that can be clearly identified as a discharge from a pipe, ditch, or other well-defined source. Non-point source pollution, by contrast, is contamination that occurs when rainwater, snowmelt, or irrigation washes off plowed fields, city streets, or suburban backyards. As this runoff moves across the land surface, it picks up soil particles and pollutants such as nutrients and pesticides. Some of the polluted runoff infiltrates into the soil to contaminate (and recharge) the groundwater below. The rest of the runoff deposits the soil and pollutants in rivers, lakes, wetlands, and coastal waters. Originating from numerous small sources, nonpoint source pollution is widespread, dispersed, and hard to pinpoint. Compared with point source pollution, it is diffuse and difficult to control or prevent. It has been estimated that non-point source pollution accounts for more than one-half of the water pollution in the United States today.

Non-Potable is a term used to describe water that is not suitable for drinking because it contains pollutants, contaminants, minerals, or infective agents.

NPDES Permit is a permit issued under the National Pollutant Discharge Elimination System (NPDES) for companies discharging pollutants directly into the waters of the United States.

Nutrient Pollution refers to the contamination of water resources by excessive inputs of nutrients. In surface waters, excess algal production is a major concern. Although natural sources of nutrients exist, major sources are typically Anthropogenic (caused by man’s activities) and include point sources such as municipal sewage-treatment plants and industrial outflows, and non-point sources such as commercial fertilizers, animal waste, and combustion emissions. Most of the recent legislation to curb nutrient pollution has been targeted towards such goals as updating sewage-treatment plants to reduce phosphorus and nitrogen in effluents, bans on phosphorous in laundry detergents, and controlling agriculture operations to control the flow of nitrogen and phosphorous from fertilizers entering natural waters.

Observation Well is a well used to monitor changes in water levels of an aquifer and to obtain samples for water quality analyses.

Outcrop describes subsurface formations which become exposed at the surface.

In water pollution, particulate matter describes solid material in either the solid or dissolved states. Insoluble particulate matter includes particulate substances that either settle from water that is allowed to stand or are removed by passing the water through a filter. Sand, clay, and some organic matter constitute insoluble particulate matter. Dissolved substances that will neither settle if water is allowed to stand nor be removed by passage through a filter, but which will be recovered if the water is allowed to evaporate, are called dissolved particulate matter. Salt is an example of this type of particulate matter. In air pollution, particulate matter is used to describe either solid particles or liquid droplets that are carried by a stream of air or other gases.

Parts Per Billion (PPB) is the number of “parts” by weight of a substance per billion parts of water. It is used to measure extremely small concentrations.

Parts Per Million (PPM) is the number of “parts” by weight of a substance per million parts of water. This unit is commonly used to represent pollutant concentrations. Large concentrations are expressed in percentages.

Parts Per Thousands (PPT) is an expression of concentration which indicates one unit is contained in a total of a thousands units. It is normally used to specify the salinity of water and commonly indicated by the symbol “‰”.

Peak hourly demand, in the absence of verified historical data, means 1.25 times the maximum daily demand (prorated to an hourly rate) if a public water supply meets the commission's minimum requirements for elevated storage capacity and 1.85 times the maximum daily demand (prorated to an hourly rate) if the system uses pressure tanks or fails to meet the commission's minimum elevated storage capacity requirement.

Perchloroethylene (PCE) (Tetrachloroethylene) is a solvent often used for degreasing and in dry cleaning which sometimes makes its way into water wells and other ground water supplies. Studies have shown that high concentrations of the chemical can cause liver and kidney damage, including cancer, in animals. In humans, however, not enough information is available to say it is a definite carcinogen. The U.S. Environmental Protection Agency’s (EPA) safe drinking water standard for tetrachloroethylene is 0.005 parts per million (ppm). Also referred to as Tetrachloroethylene and Perclene.

Percolating waters are underground waters whose course and boundaries are incapable of determination. They pass through the ground beneath the earth’s surface without a definite channel. May be rainwater slowly infiltrating through the soil or water seeping through the banks or the bed of a stream, but these waters have left the flow of the stream so that they no longer may be characterized as a part of the stream flow. It is presumed that ground waters percolate.

Percolation is the movement, under hydrostatic pressure, of water through the interstices of a rock or soil. This includes the movement of water within a porous medium such as soil toward the water table without a definite channel. It is also used to describe slow seepage of water through a filter.

A Permit is a written document which grants authority to take unused water and put it to Beneficial Use. If all requirements of the permit are satisfied, then the permit for water appropriation can mature into a license or Perfected Water Right. (2) (Discharge) A legally binding document issued by a state or federal permit agency to the owner or manager of a point source discharge. The permit document contains a schedule of compliance requiring the permit holder to achieve a specified standard or limitation (by constructing treatment facilities or modifying plant processes) by a specified date. Permit documents typically specify monitoring and reporting requirements to be conducted by the applicant as well as the maximum time period over which the permit is valid.

Permitted Well is a well from which water is used for other than a domestic use and which has received a permit for a Beneficial Use from the water regulatory body or other appropriate official.

Place of Use describes the specific location, typically documented in a water right permit, where water is applied or used. A water user cannot use water at another location without transferring the right or obtaining a new right.

Point of Diversion is the point from which water is diverted from a source.

Point(s) of Diversion is the point(s) specified in a water right permit from which water is diverted from a source. Also refers to a river, stream, canal, or reservoir where irrigation water is diverted into an irrigation project.

Pollutant is something that pollutes, especially a waste material that contaminates air, soil, or water. It is 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 their usefulness or render them offensive.

Pollution is the alteration of the physical, thermal, chemical, or biological quality of, or the contamination of, any water in the state that renders the water harmful, detrimental, or injurious to humans, animal life, vegetation, or property, or to public health, safety, or welfare, or impairs the usefulness of the public enjoyment of the waters for any lawful or reasonable purpose; Any alteration in the character or quality of the environment which renders it unfit or less suited for certain uses.

Potable Water is water that is used for or intended to be used for human consumption or household use. Specifically, freshwater that generally meets the standards in quality as established in the U.S. Environmental Protection Agency (EPA) Drinking Water Standards for drinking water throughout the United States. Potable water is considered safe for human consumption and is often referred to as Drinking Water. Freshwater that exceeds established chloride and dissolved solids limits is often referred to as slightly saline, brackish, or nonpotable water and is either diluted with fresher water or treated through a desalination process to meet potable-water standards for public supply.

Priority is the term used to determine who has seniority rights; the first in time is the first in right.

Prior Appropriation is the system for allocating water to private individuals used in the western United States under which (1) the right to water was acquired by diverting water and applying it to a beneficial use and (2) a right to water acquired earlier in time is superior to a similar right acquired later in time. In most states water rights are not now acquired by diverting water and applying it to a beneficial use. Such a system is referred to as the constitutional method of appropriation. Water rights are acquired by application, permit, and license, which may not require diversion and application to a beneficial use. Superiority of right is based on earliest in time and has no reference to whether two rights are for a similar use. The doctrine of Prior Appropriation was in common use throughout the arid west as early settlers and miners began to develop the land. The prior appropriation doctrine is based on the concept of “First in Time, First in Right.” The first person to take a quantity of water and put it to Beneficial Use has a higher priority of right than a subsequent user. Under drought conditions, higher priority users are satisfied before junior users receive water. Appropriative rights can be lost through nonuse; they can also be sold or transferred apart from the land. Contrast with Riparian Water Rights.

Prior Appropriation Doctrine is a concept in water law under which a right to a given quantity of water is determined by such a procedure as having the earliest Priority Date. It is a system for allocating water to private individuals used in most of the western United States. The doctrine of Prior Appropriation was in common use throughout the arid west as early settlers and miners began to develop the land. The prior appropriation doctrine is based on the concept of “First in Time, First in Right”. The first person to take a quantity of water and put it to Beneficial Use has a higher priority of right than a subsequent user. Under drought conditions, higher priority users are satisfied before junior users receive water. Appropriative rights can be lost through nonuse; they can also be sold or transferred apart from the land. Also see Littoral Water Rights and Prescribed Water Rights.

Priority is the concept that the person first using water has a better right to it than those commencing their use later. An appropriator is usually assigned a “priority date”. However, the date is not significant in and of itself, but only in relation to the dates assigned other water users from the same source of water. Priority is only important when the quantity of available water is insufficient to meet the needs of all those having a right to use water. See (Prior) Appropriation Doctrine and Appropriative Water Rights.

Priority Date is the name for the date of establishment of a water right; the officially recognized date associated with a water right. The rights established by application have the application date as the date of priority. Relative to other water rights, the priority date may make a water right senior (predating other rights) or junior (subordinate to other rights).

Public water supply well is a well that produces the majority of its water for use by a public water system.

A Public Water System (PWS) is a system for the provision to the public of water for human consumption through pipes or other constructed conveyances, which includes all uses described under the definition for drinking water. Such a system must have at least 15 service connections or serve at least 25 individuals at least 60 days out of the year. This term includes; any collection, treatment, storage, and distribution facilities under the control of the operator of such system and used primarily in connection with such system, and any collection or pretreatment A system for provision to the public of piped water for human consumption, if such system has at least 15 service connections (such as households, businesses, or schools) or regularly serves at least 25 individuals daily for at least 60 days out of the year.

Rate includes every compensation, tariff, charge, fare, toll, rental, and classification or any of them demanded, observed, charged, or collected, whether directly or indirectly, by any retail public utility, or water or sewer service supplier, for any service, product, or commodity.

Each person receiving a separate bill for retail water service is considered a ratepayer, but no person shall be considered as being more than one ratepayer notwithstanding the number of bills received. A complaint or a petition for review of a rate change shall be considered properly signed if signed by any person, or spouse of any such person, in whose name utility service is carried.

Reasonable Use is a term that describes a rule with regard to percolating or riparian water restricting the landowner to a reasonable use of his own rights and property in view of and qualified by the similar rights of others, and the condition that such use not injure others in the enjoyment of their rights.

Recharge is a name used for water that infiltrates the water table of an aquifer.

Recharge zone is that area where the stratigraphic units constituting the Edwards Aquifer crop out, including the outcrops of other geologic formations in proximity to the Edwards Aquifer, where caves, sinkholes, faults, fractures, or other permeable features would create a potential for recharge of surface waters into the Edwards Aquifer. The recharge zone is identified as that area designated as such on official maps located in the agency's central office and in the appropriate regional office.

Reclaimed water is the term used to describe municipal or industrial wastewater or process water that is under the direct control of the treatment plant owner/operator, or agricultural tailwater that has been collected for reuse, and which has been treated to a quality suitable for the authorized beneficial use.

A reservoir is a pond, lake, or basin, either natural or artificial, for the storage, regulation, and control of water. Another definition of reservoir is an artificially created lake in which water is collected and stored for future use.

Retail public utility is a term used to describe any person, corporation, public utility, water supply or sewer service corporation, municipality, political subdivision or agency operating, maintaining, or controlling in this state facilities for providing potable water service or sewer service, or both, for compensation.

Retention is that part of the precipitation falling on a drainage area that does not escape as a surface streamflow, during a given period.

Retention Basin is a permanent lake or pond used to slow stormwater runoff. Also see Detention Basin.

A retention facility is a stormwater storage facility that normally holds water at a controlled level to serve functions such as recreation, aesthetic, and water supply. Stormwater runoff is temporarily stored above the controlled stage. Examples of types of retention storage reservoirs are permanent ponds in residential and commercial areas and in open spaces.

Return flow is that portion of state water diverted from a water supply and beneficially used which is not consumed as a consequence of that use and returns to a watercourse. Return flow includes sewage effluent.

The amount of water that reaches a ground or surface water source after release from the point of use and thus becomes available for further use is called return water. In irrigation return water is the drainage water from irrigated farmlands that re-enters the water system to be used further downstream.

Reuse is a term used to describe the authorized use for one or more beneficial purposes of use of water that remains unconsumed after the water is used for the original purpose of use and before that water is either disposed of or discharged or otherwise allowed to flow into a watercourse, lake, or other body of state-owned water.

Reuse Water is water that is discharged by one user and is used by other users. Sometimes, it also means water discharged by one unit and used by other units in the same plant.

Riparian pertains to the banks of a river, stream, waterway, or other, typically, flowing body of water as well as to plant and animal communities along such bodies of water. This term is also commonly used for other bodies of water, e.g., ponds, lakes, etc., although Littoral is the more precise term for such stationary bodies of water. Also refers to the legal doctrine (Riparian Doctrine and Riparian Water Rights) that says a property owner along the banks of a surface water body has the primary right to withdraw water for reasonable use.

Riparian Doctrine is the system for allocating water typically used in England and the Eastern United States, in which owners of lands along the banks of a stream or water body have the right to Reasonable Use of the waters and a Correlative Right protecting against unreasonable use by others that substantially diminishes the quantity or quality of water.  The right is appurtenant to the land and does not depend on prior use. Under this doctrine, ownership of land along a stream or river, such as riparian lands, is an absolute prerequisite to a right to use water from that body of water and each such landowner has an equal right to withdraw “reasonable” amounts of water so long as downstream landowners are not unreasonably damaged. In most cases, riparian water right disputes are resolved through the courts.

Riparian Rights are the rights of an owner whose land abuts water. They differ from state to state and often depend on whether the water is a river, lake, or ocean. The doctrine of riparian rights is an old one, having its origins in English common law. Specifically, persons who own land adjacent to a stream have the right to make reasonable use of the stream’s natural flow on those lands within the watershed. (The emphasis on natural flow means that riparian rights cannot be claimed for long-term storage of water in a reservoir.) Riparian users of a stream share the streamflow among themselves, and the concept of priority of use (Prior Appropriation Doctrine) is not applicable. Under drought conditions, the users share shortages. Riparian rights cannot be sold or transferred for use on nonriparian land. Riparian rights to the waters of a lake, as opposed to a flowing stream, are often referred to as Littoral Water Rights.

Rule of Capture is Texas' guiding principle for groundwater management is the rule of capture. Adopted in 1904, this rule gives the landowner the right to capture an unlimited amount of groundwater by tapping into the underlying aquifer. The general rule is that a landowner who extracts or “captures” groundwater from a well that bottoms within the subsurface of his land acquires absolute ownership of the substance, even if it is drained from the subsurface of another’s land. This is why the rule of capture is often referred to as the “law of the biggest pump.” With this legal right, Texas landowners face no liability to neighbors who might claim the pumping has depleted their wells -- as long as the water is retrieved without malice or willful waste. By relying on the rule of capture, Texas’ historical approach has been to limit all public control of groundwater. In this regard, Texas remains the only western state to continue to adhere to the rule of capture, which stems from English common law. However, the Rule has been limited by enactment of Chapter 36 of the Texas Water Code, and through formation of Groundwater Conservation Districts.

Runoff is the portion of precipitation that moves from the land to surface water bodies which is not intercepted by vegetation, absorbed by the land surface or evaporated, and thus flows overland into a depression, stream lake or ocean (runoff called “immediate subsurface runoff” also takes place in the upper layers of the soil). It is the same as streamflow unaffected by artificial diversions, imports, storage, or other works of man in or on the stream channels. Runoff may be classified according to speed of appearance after rainfall or melting snow as direct runoff or base runoff, and according to source as surface runoff, storm interflow, or ground-water runoff. Runoff is also defined as the depth to which a drainage area would be covered if all of the runoff for a given period of time were uniformly distributed over it.

Safe Drinking Water Act [SDWA] (Public Law 93–523) is an amendment to the Public Health Service Act which established primary and secondary quality standards for drinking water. The SDWA was passed in 1976 to protect public health by establishing uniform drinking water standards for the nation. In 1986 SDWA Amendments were passed that mandated the U.S. Environmental Protection Agency (EPA) to establish standards for 83 drinking water contaminants by 1992 and identify an additional 25 contaminants for regulation every 3 years thereafter.

Sanitary control easement is a legally binding document securing all land, within 150 feet of a public water supply well location, from pollution hazards. This document must fully describe the location of the well and surrounding lands and must be filed in the county records to be legally binding.

Streamflow is the water flowing within a watercourse.

A Shaft is any vertically oriented excavation, whether constructed by drilling or mining techniques, where the depth of the excavation is greater than its diameter, the excavation penetrates into or through the base of the uppermost water-bearing strata, and the primary purpose of the excavation is the transport of workers and materials to and from a destination, at depth, for purposes of geological studies, access to existing and planned subsurface mine workings, or for ventilation of those workings.

Sodium Hypochlorite is a water solution of sodium hydroxide and chlorine, NaOCl, used as a primary disinfectant in water treatment.

A Spring is a concentrated discharge of ground water coming out at the surface as flowing water; a place where the water table crops out at the surface of the ground and where water flows out more or less continuously. Its occurrence depends on the nature and relationship of rocks, especially permeable and impermeable strata, on the position of the water table, and on the topography.

Standby fee is a charge, other than a tax, imposed on undeveloped property for the availability of water, wastewater, or drainage facilities and services. Standby fee does not mean an impact fee, tap fee, or a connection fee.

State water is the water of the ordinary flow, underflow, and tides of every flowing river, natural stream, and lake, and of every bay or arm of the Gulf of Mexico, and the storm water, floodwater, and rainwater of every river, natural stream, and watercourse in the state. State water also includes water which is imported from any source outside the boundaries of the state for use in the state and which is transported through the beds and banks of any navigable stream within the state or by utilizing any facilities owned or operated by the state. Additionally, state water injected into the ground for aquifer storage and recovery project remains state water. State water does not include percolating groundwater; nor does it include diffuse surface rainfall runoff, groundwater seepage, or spring water before it reaches a watercourse.

Streamflow is the flow of water in streams, rivers, and other channels.

Submetered utility service is a water utility service that is master metered for the owner by the retail public utility and individually metered by the owner at each dwelling unit; it is measured by point-of-use submeters.

Subsidence means the lowering in elevation of the land surface caused by withdrawal of groundwater. Typically this may result from the over-pumping of a basin’s water table and the inability of the soils to re-absorb water from natural or artificial injection. Also frequently results from overdrafts of the aquifer and its inability to fully recharge, a process termed Aquifer Compaction.

Tail Water, when used in Hydraulics, is water in a river or channel immediately downstream from a structure. In Irrigation, tail water is the water that reaches the lower end of a field. Tail water is not necessarily lost; it can be collected and reused on the same or adjacent fields.

A tap fee is the charge to new customers for initiation of service where no service previously existed. The fee for water service may include the cost of physically tapping the water main and installing meters, meter boxes, fittings, and other materials and labor. A tap fee for sewer service may include the cost of physically tapping the main and installing the utility's service line to the customer's property line, fittings, and other material and labor. Water or sewer taps may include setting up the new customer's account, and allowances for equipment and tools used. Extraordinary expenses such as road bores and street crossings and grinder pumps may be added if noted on the utility's approved tariff. Other charges, such as extension fees, buy-in fees, impact fees, or contributions in aid of construction (CIAC) are not to be included in a tap fee.

Tariff is the schedule of a retail public utility containing all rates, tolls, and charges stated separately by type or kind of service and the customer class, and the rules and regulations of the retail public utility stated separately by type or kind of service and the customer class.

TDS (Total Dissolved Solids) are all the solids (usually mineral salts) that are dissolved in water. TDS is a standard used to evaluate water quality. The inorganic salts are measured by filtering a water sample to remove any suspended particulate material, evaporating the water, and weighing the solids that remain. An important use of the measure involves the examination of the quality of drinking water. Water that has a high content of inorganic material frequently has taste problems and/or water hardness problems. High TDS concentrations exert varying degrees of osmotic pressures and often become lethal to the biological inhabitants of an aquatic environment. The common and synonymously used term for TDS is “salt”. TDS is usually expressed in milligrams per liter.

Tetrachloroethylene (Perchloroethylene, PCE) is a solvent often used for degreasing and in dry cleaning which sometimes makes its way into water wells and other ground water supplies. Studies have shown that high concentrations of the chemical can cause liver and kidney damage, including cancer, in animals. In humans, however, not enough information is available to say it is a definite carcinogen. The U.S. Environmental Protection Agency’s (EPA) safe drinking water standard for tetrachloroethylene is 0.005 parts per million (ppm). Also referred to as Perchloroethylene (PCE) and Perclene.

Total Maximum Daily Load (TMDL) is a term relating to water quality that describes the maximum quantity of a particular water pollutant that can be discharged into a body of water without violating a water quality standard. The amount of pollutant is set by the U.S. Environmental Protection Agency (EPA) when it determines that existing, Technology-Based effluent standards on the water pollution sources in the area will not achieve one or more Ambient Water Quality Standards. The process results in the allocation of the TMDL to the various Point Sources (PS) of pollutants in the area.

Transfer (Water Right) is a term used to describe the passing or conveyance of title to a water right; a permanent assignment as opposed to a temporary lease or disposal of water.

Trihalomethanes (THMs) is the name for any of several synthetic organic compounds formed when chlorine combines with organic materials in water during the disinfection process. The most common THM is chloroform. THM is also used to describe a group of low-molecular-weight, halogenated hydrocarbons, derivatives of methane, CH4, in which three halogen atoms (chlorine, bromine, or iodine) are substituted for three of the hydrogen atoms. The subsequent substances typically include the compounds of chloroform (CHCl3), dichlorobromomethane (CHCl2Br), dibromochloromethane (CHClBr2), and bromoform (CHBr3). The sum of these four compounds is referred to as Total Triholomethanes (TTHMs). The group includes suspect human Carcinogens. Small amounts of THMs have been detected in raw water collected from surface sources used as a public water supply, and concentrations have been shown to be increased during the chlorination phase of the water purification process.

The Trinity Aquifer is actually a group of several geologic deposits divided up into several distinct formations, and each formation is in turn comprised of several layers called members.  This group, which is collectively referred to as the Trinity, extends in a band through the central part of the State from the Red River to the eastern edge of Bandera and Medina counties.  It is the primary water source for much of the Hill Country.  Most users in northern Bexar, Bandera, Kendall, Comal, and Kerr counties get their water from the Trinity.  At the same time, all of Bandera, most of Kerr and Kendall, and large parts of Comal and Bexar counties serve as drainage or catchment area for the Edwards Aquifer.

Turbidity is the measure of the reduced transparency of water due to suspended material which carries water quality implications. The term “turbid” is applied to waters containing suspended matter that interferes with the passage of light through the water or in which visual depth is restricted. The turbidity may be caused by a wide variety of suspended materials, such as clay, silt, finely divided organic and inorganic matter, soluble colored organic compounds, plankton and other microscopic organisms and similar substances. Turbidity in water has public health implications due to the possibilities of pathogenic bacteria encased in the particles and thus escaping disinfection processes. Turbidity interferes with water treatment (filtration), and affects aquatic life; excessive amounts of turbidity also make water aesthetically objectionable. The degree of the turbidity of water is measured by a Turbidimeter. The higher the intensity of scattered light, the higher the turbidity. Turbidity is expressed in nephelometric turbidity units (NTU) or Formazin turbidity units (FTU) depending on the method and equipment used.

The amount of state water remaining in a watercourse or other source of supply after taking into account complete satisfaction of all existing water rights valued at their full authorized amounts and conditions is called unappropriated water.

An unconfined aquifer is an aquifer containing water that is not under pressure; the water level in a well is the same as the water table outside the well. An unconfined aquifer is made up of loose material such as sand or gravel that has not undergone lithification (settling). In an unconfined aquifer the upper boundary is the top of the Zone of Saturation (water table).

Underground Storage Tank refers to any one or combination of underground tanks and any connecting underground pipes used to contain an accumulation of regulated substances. Underground storage tanks are located at least partially underground and designed to hold gasoline or other petroleum products or chemicals.

Underground Water is water that is below the surface of the ground, which is often referred to as groundwater, subsurface water or subterranean water. It is important that this water is kept clean, and in many cases it needs to be protected and conserved within a district in order to maintain the different ecosystems.

Vested Water Right is the right to use either surface or ground water acquired through more or less continual beneficial use prior to the enactment of water law pertaining to the source of the water. These claims become final through Adjudication. (2) A fully executed or finalized appropriative right to use the waters of a state for a beneficial purpose.

Volatile Organic Chemicals (VOCs) are chemicals of an organic nature (containing hydrogen, oxygen, and carbon) which readily volatilize, or travel from the water into the air. Most of these substances are industrial chemicals and solvents. They include light alcohols, acetone, trichloroethylene, perchloroethylene, dichloroethylene, benzene, vinyl chloride, toluene, and methylene chloride. These potentially toxic chemicals are used as solvents, degreasers, paints, thinners, and fuels. Because of their volatile nature, they readily evaporate into the air, increasing the potential exposure to humans. Due to their low water solubility, environmental persistence, and widespread industrial use, they are commonly found in soil and water. The U.S. Environmental Protection Agency (EPA) maintains a listing of VOCs that are regulated with respect to Maximum Contaminant Levels (MCLs) as part of the Safe Drinking Water Act (SDWA). Also referred to as Volatile Organic Compounds (VOCs).

Volatile Organic Compounds (VOCs) are organic compounds that can be isolated from the water phase of a sample by purging the water sample with inert gas, such as helium, and subsequently analyzed by gas chromatography. Many VOCs are manmade chemicals that are used and produced in the manufacture of paints, adhesives, petroleum products, pharmaceuticals, and refrigerants. They are often components of fuels, solvents, hydraulic fluids, paint thinners, and dry cleaning agents commonly used in urban settings. VOC contamination of drinking-water supplies is a human health concern because many are toxic and are known or suspected human carcinogens. Also referred to as Volatile Organic Chemicals (VOCs).

The diversion of water if the water is not used for a beneficial purpose or the use of that amount of water in excess of that which is economically reasonable for an authorized purpose when reasonable intelligence and reasonable diligence are used in applying the water to that purpose is considered Waste. Waste may include, but is not limited to, the unreasonable loss of water through faulty design or negligent operation of a water delivery, distribution or application system, or the diversion or use of water in any manner that causes or threatens to cause pollution of water. Waste does not include the beneficial use of water where the water may become polluted because of the nature of its use, such as domestic or residential use, but is subsequently treated in accordance with all applicable rules and standards prior to its discharge into or adjacent to water in the state so that it may be subsequently beneficially used.

Wastewater is a combination of liquid and water-carried pollutants from homes, businesses, industries, or farms; a mixture of water and dissolved or suspended solids. Because of quality, quantity, or time of occurrence, disposal is more economical than use at the time and point of its occurrence. Waste water to one user may be a desirable supply to the same or another user at a different location. Also referred to as Domestic Wastewater.

A wastewater treatment plant, sometimes referred to as a water treatment plant, is a water effluent treatment facility containing a series of tanks, screens, filters and other mechanical, biological, and chemical processes by which pollutants are removed from water.

Water and sewer utility refers to any person, corporation, cooperative corporation, affected county, or any combination of those persons or entities, other than a municipal corporation, water supply or sewer service corporation, or a political subdivision of the state, except an affected county, or their lessees, trustees, and receivers, owning or operating for compensation in this state equipment or facilities for the production, transmission, storage, distribution, sale, or provision of potable water to the public or for the resale of potable water to the public for any use or for the collection, transportation, treatment, or disposal of sewage or other operation of a sewage disposal service for the public, other than equipment or facilities owned and operated for either purpose by a municipality or other political subdivision of this state or a water supply or sewer service corporation, but does not include any person or corporation not otherwise a public utility that furnishes the services or commodity only to itself or its employees or tenants as an incident of that employee service or tenancy when that service or commodity is not resold to or used by others.

Water Banking is a water conservation and use optimization system whereby water is reallocated for current use or stored for later use. Water banking may be a means of handling surplus water resources and may involve aquifer recharge or similar means of storage. Typically, under such arrangements, an agency is created with the authority to purchase, sell, hold, and transfer water and water rights in addition to serving as a negotiator between buyers and sellers. In its broadest sense, all water rights would be covered under such water banking arrangements to include surface water, groundwater, treated wastewater effluent, and irrigation tailwater. Generally, participants in water banking arrangements will have their water rights protected from cancellation (non beneficial use) for a specific period so long as their water is “deposited” in the water bank.

Water Marketing involves transactions between willing buyers and willing sellers: a temporary or permanent transfer of water or water rights at an agreed price. Marketing is a concept of water transfer and use borne out of increased demand by urban populations for water whereby a holder of water rights is allowed to sell or lease those rights in an open market to the highest bidder. Water marketing arrangements, however, can only succeed where necessary water transport and delivery systems exist between supply points and demand points.

The person appointed by the executive director of the TCEQ to administer water rights in a given water division, segment of a water division, or group of water divisions is the water master.

Water Quality is used to describe the laws of water, usually in respect to its suitability for a particular purpose.

Water Rights are rights acquired under the laws of this state to impound, divert, or use state water. They involve the legal right to use a specific quantity of water, on a specific time schedule, at a specific place, and for a specific purpose. Water rights are legally-protected rights, granted by law, to take possession of water occurring in a water supply and to put it to Beneficial Use.

Watershed is a term used to designate the area drained by a stream and its tributaries, or the drainage area upstream from a specified point on a stream.

Any nonprofit corporation organized and operating under Texas Water Code, Chapter 67, that provides potable water or sewer service for compensation and that has adopted and is operating in accordance with by-laws or articles of incorporation which ensure that it is member-owned and member-controlled is a water supply or sewer service corporation. The term does not include a corporation that provides retail water or sewer service to a person who is not a member, except that the corporation may provide retail water or sewer service to a person who is not a member if the person only builds on or develops property to sell to another and the service is provided on an interim basis before the property is sold.

A water well is an excavation (pit, hole, tunnel), generally cylindrical in form and often walled in, drilled, dug, driven, bored, or jetted into the ground to such a depth as to penetrate water-yielding geologic material and allow the water to flow or to be pumped to the surface. An artificial excavation put down by any method for the purposes of withdrawing water from the underground aquifers is considered a water 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.

A well is a bored, drilled, or driven shaft, or an artificial opening in the cones of depression for two or some other method, where the depth of the well is greater than its largest surface dimension. It is not a surface pit, surface excavation, or natural depression.

One or more wells producing water from a subsurface source or a tract of land which contains a number of wells for supplying a large municipality or irrigation district is a well field.

If the cones of depression for two or more wells overlap, there is said to be well interference. This interference reduces the water available to each of the wells.

The potable water or sewer service, or both, provided to a person, political subdivision, or municipality who is not the ultimate consumer of the service is called wholesale water or sewer service

Yield is the quantity of water expressed either as a continuous rate of flow (e.g., cubic feet per second – cfs) or as a volume per unit of time (e.g., acre-feet per year – AFY) which can be collected for a given use or uses from surface- or ground-water sources on a watershed. The yield may vary with the use proposed, with the plan of development, and also with economic considerations. Yield is also used to describe the total runoff and the streamflow in a given interval of time derived from a unit area of watershed. It is determined by dividing the observed streamflow at a given location by the drainage area above that location and is usually expressed in cubic feet per second per square mile.