Volume Unit Conversion Chart


Abstraction: withdrawal from a source

Aggregate: combined total from multiple collections of data; aggregate supply is the total quantity of goods produced in a specified market.

Allowance: permit conferring the right to a fixed quantity of a good or a service; an abstraction allowance permits the bearer to withdraw a specified quantity of water.

Alternative energy: any form of usable energy which replaces fossil fuels and other traditional sources of energy.

Anaerobic: without air. In wastewater treatment it simply indicates an absence of an electron acceptor such as nitrate, sulfate or oxygen.

Aqueducts: a type of canal built to channel water. It is often elevated.

Aquifer: A geological formation that is permeable to water, and can store and transmit water to a well or spring. It can be composed of sand, gravel, rock, soil.

Brine: High-salinity concentrate that is removed from water during desalination.

Cogeneration: generating both electricity and useful heat from a power station.

Combined cycle technologies: These technologies follow one thermodynamic cycle with another of a different kind. This results in more efficient systems since individual cycles generally use only a fraction of the energy generated from their fuel and lose the rest of the heat.

Derivative: financial instrument based on the value of an underlying asset or commodity

Desalination: The process of removing salts from seawater. Desalinated water can be a source of water.

Discount rate: rate of return on an investment, usually expressed as a percentage; used to translate the value of an investment at its time of occurrence to its value at present (analogous to the interest rate, which is used to translate the present value of an investment into a value for that investment at a different time)

Effluent: Water that is treated after use mainly from sewage, and can be recycled to be used as a source of water.

Evapotranspiration: The net water loss from evaporation of water from surfaces of plants and transpiration.

Fallow: When a field is left fallow no crops are planted in it. This is generally only a temporary state, for a season or a year.

Fallow fields: Parts of the farmland that is left unplowed and unproductive during the growing season.

Flood irrigation: An irrigation method, where the furrows between crops are filled with water. This results in a large surface area of water.

Forwards: derivative based on expected future prices of a certain commodity good; traded over-the-counter between specified buyers and sellers

Futures: derivative based on expected future prices of a certain commodity good; traded at an exchange or clearinghouse without specification of buyers

Gray Water: see Effluent

Groundwater: Water that is naturally found beneath the ground, stored in aquifers. This water is an accumulation of gradual recharge from the run-off and surface water over centuries.

Gypsum: a soft mineral composed of calcium sulphate dehydrate.

Halite: otherwise known as sodium chloride or rock salt.

High Plains: A semi-arid region in central United States, that consists of parts of Colorado, Kansas, Nebraska, Montana, New Mexico, Oklahoma, Texas, Wyoming. The High Plains region relies heavily on Ogallala Aquifer and sustains a significant portion of agriculture.

Hydroelectric power: Power generated usually by damming rivers and channeling the water through turbines, harvesting the mechanical energy.

Levelized cost: total discounted cost of a capital asset over its lifetime divided by the discounted quantity of the good or service to be produced by the asset over its lifetime.

Micro-hydropower systems: generation of hydroelectric power on a very small scale, generally for a single company or village. It does not require powerful rivers.

Non-point source pollution: The source is not a single easily identifiable place. For example it may be runoff from agriculture.

Ogallala Aquifer: one of the largest aquifers in the southwest of the United States. It spans from South Dakota to Texas, and sustains a significant portion of the agriculture in the United States.

Options: derivative conferring the right to purchase a specified quantity of a certain commodity good in the future; traded over-the-counter between specified buyers and sellers

Overdraft: groundwater mining, usually expressed as the gross decrease in saturated thickness of an aquifer

Point source pollution: pollution from a single identifiable source such as a waste water outlet.

Price elasticity of demand: percent change in quantity of a good demanded divided by percent change in price of the good; ranges from zero (when quantity demanded remains constant regardless of price) to negative infinity. Price elasticity of demand can be classified by the following definitions under the assumption that price and quantity demanded are inversely correlated:

  • Elastic- having an elasticity of absolute value greater than one; if price of a good with elastic demand increases, the producer's total revenue from (and the consumer's total spending on) that good decreases.
  • Inelastic- having an elasticity of absolute value less than one; if price of a good with inelastic demand increases, the producer's total revenue from (and the consumer's total spending on) that good increases.
  • Unit-elastic- having an elasticity of absolute value equal to one; if price of a good with unit-elastic demand increases, the producer's total revenue from (and the consumer's total spending on) that good remains unchanged.
  • *Note: price elasticity of demand needs not be fixed for a particular good, as different combinations of prices and quantities demanded may result in different values for elasticity depending on the relationship between price and quantity demanded.

Primary treatment: removing contaminants in wastewater through physical mechanism; for example: using screens to filter solids

Progressive: affecting individuals based on ability to pay; higher-income individuals pay greater amounts of money as tax under a progressive taxation structure.

Recharge: the replenishing of water in aquifers. The increase in the amount of water stored in the aquifer.

Recharge zones: The area in which water enters an aquifer

Reclaimed water: see Effluent

Regressive: disproportionately affecting lower-income individuals; each individual pays the same amount of money as tax under a regressive taxation structure.

Runoff: The portion of precipitation that runs into streams and other bodies of surface water.

Secondary treatment: a biological process that removes organic waste from wastewater; this is typically done through aeration tanks in which bacteria feeds on nutrients in the wastewater

Tertiary treatment: advanced wastewater treatment that may include fitration, ammonia removal, and/or disinfection

Thermoelectric power: electricity is produced by converting heat to some form of mechanical motion which is then converted to electricity. Common fuel sources include coal, oil, natural gas, and nuclear energy.v

Turbidity: A measure of water opacity caused by suspended solids in the water

Water competency: Power of flowing water

Watershed: In North American usage this refers to a drainage basin. The area drained by a river and its tributaries.

Winters Doctrine: Established in the Winters v. United States case. The U.S. Supreme Court ruled that an Indian Reservation has the right to reserve water necessary for the purpose of the Reservation, with priority given to the date of the establishment of the Reservation.


AFY: acre-fee per year

ASCE: American Society of Civil Engineers

BTU: British Thermal Unit. The amount of heat required to raise the temperature of one pound of liquid water by one degree from 60o to 61o Fahrenheit at a constant pressure of one atmosphere. Approximately 1054-1060J.

CBO: Congressional Budget Office

CF: Conventional furrow, a type of irrigation method

CIMIS: California Irrigation Management Information System

EPA: Environmental Protection Agency

FEMA: Federal Emergency Management Agency

GDP: Gross Domestic Product

GM crops: Genetically Modified crops

GMDs: Groundwater Management Districts, A system used in Kansas, that is used manage groundwater resources

HETs: High Efficiency Toilets

LEPA: Low Energy Precision Application, a type of irrigation method

LESA: Low Elevation Spray Application, a type of irrigation method

MESA: Mid-Elevation Spray Application, a type of irrigation method

MGD: million gallons per day

MWRSA: Monterey Wastewater Reclamation Study for agriculture

NAFTA: North American Free Trade Agreement

NAWTA: North American Water Trading Authority

NETL: the National Energy Technology Laboratory

NRDs: Natural resource districts, a system used in Nebraska to manage groundwater resources

NWC: Australian National Water Commission.

PIA: Practicably Irrigable Acreage, this is based on the Native American population on a reservation

POTWs: Publicly Owned Treatment Works

SDI: Subsurface drip irrigation, a type of irrigation method

SF: Surge flow, a type of irrigation method

TDS: Total Dissolved Solids

TSS: Total Suspended Solids

USDA: United States Department of Agriculture

USDIRB: United States Department of the Interior Reclamation Bureau

USDOI: United States Department of the Interior

USEPA: United States Environmental Agency, also known as EPA

USGS: United States Geological Survey

WRPs: Water Reclamation Plants