Glossary

 

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Acre-foot

Large amounts of water are measured by the acre-foot. One acre-foot is about 326,000 gallons, or enough water to cover one acre to a depth of one foot. An acre-foot can supply the household needs of two four-person families for one year.
 

Agricultural Water

Water used mostly for irrigating groves and crops, accounting for approximately 15 to 20 percent of Water Authority demand; municipal and industrial water makes up the remaining 80 to 85 percent; water sold under MWD and Authority Interruptible Agricultural Delivery Program.
 

Aqueduct Protection Program

A Capital Improvement Program (CIP) project of the San Diego County Water Authority, which assesses the service life and corrosion protection of Authority pipelines in the field and defines projects for the Authority’s Relining Program. (link to 4.1.1.2.6 Pipeline Relining)
 

Aquifer

Any unit of rock or sediment that is capable of both storing water and transmitting water to wells and springs. In the Water Authority's service area, the principle aquifer materials are alluvium, semi-consolidated sediment, and to a lesser degree, consolidated sediment, residuum and fractured crystalline rock. An aquifer stores groundwater.
 

Average Year

A year that is modeled as having the calculated average of water volume to meet the demands in that water year.
 

Bay-Delta

The Delta (Bay-Delta) is formed by the confluence of the state’s two largest rivers: the Sacramento flowing south from its headwaters near Mt. Shasta and the San Joaquin flowing north from its origins high in the southern Sierra Nevada. Joining the Sacramento and the San Joaquin are the Mokelumne and the Cosumnes rivers that comprise the Bay-Delta’s watershed, draining nearly 50 percent of the California’s runoff. These waters of the Bay-Delta flow westward, through 57 man-made levied islands and tracks. Pumping stations move a portion of this water throughout the state: the State Water Project, the federal Central Valley Project, Contra Costa Canal, North Bay Aqueduct, City of Vallejo diversion and the Western Delta Industry diversion. The remainder of Bay-Delta water flows to farms and communities within the Bay-Delta, and then out to sea through a series of bays.
 

BMPs (Best Management Practices)

Generally, a set of standardized efficiencies. The Water Authority refers to BMPs as a set of water conservation measures agreed to by participants in the California Urban Water Conservation Council
 

Board of Directors

The Water Authority's Board of Directors consists of at least one representative from each of its 24 member agencies. The representative is appointed by the member agency, with the consent and approval of that member agency.
 

Bond

A promise to repay money borrowed, plus interest, over a specified period of time.

Bond Issue—A means of raising large amounts of money for major projects by selling bonds.
 

Brackish Water

Somewhat salty water, often found in groundwater aquifers. The water has a mineral content between freshwater and seawater.
 

California Environmental Quality Act (CEQA)

A statute that requires state and local agencies to identify the significant environmental impacts of their actions and to avoid or mitigate those impacts, if feasible. More information on CEQA can be found here: http://ceres.ca.gov/ceqa/.
 

California-Federal (CALFED) Bay-Delta Program

A state and federal joint planning organization established to develop solutions for Bay-Delta issues.
 

Carryover Storage

A volume of storage dedicated to storing water during a wet year for future use in a dry year.
 

Capital Improvement Program (CIP)

Initiated in 1989 to plan and implement projects needed to meet the region's future water demands. Projects in the Capital Improvement Program include: Constructing new facilities to increase operational flexibility and capacity to deliver water, particularly during times of peak usage; rehabilitating existing facilities by replacing or relining aging pipelines; increasing local water storage by 100,000 acre-feet; and developing water treatment.
 

Certification

A decision by the lead agency that the Final Environmental Impact Report (FEIR) has been completed in compliance with the California Environmental Quality Act and that the information contained therein reflects the lead agency's independent judgment and analyses. The lead agency must consider the information in the FEIR prior to approving the project.
 

Conjunctive Use

Storing imported water in a local aquifer, in conjunction with groundwater, for later retrieval and use.
 

Colorado River Aqueduct

The Metropolitan Water District’s aqueduct that conveys water from the Colorado River to the Southern California coastal plain.
 

Colorado River Lower Basin states

The three states that are fed from the lower basin of the Colorado River: California, Arizona, and Nevada.
 

Conservation

The preservation of a physical quantity of water, or the deferral of use of that same amount of water.
 

Conventional treatment

A method of treating water, which consists of mixing, coagulation-flocculation, sedimentation, filtration, and disinfection. Similar to direct filtration with the addition of flocculation and sedimentation.
 

Cubic foot


A frequent water industry term of measurement, as in cubic feet per second. One cubic foot (cf) equals 7.48 gallons. A cubic foot per second is 450 gallons per minute.
 

Delta

The Delta also known as the Bay-Delta is formed by the confluence of the state’s two largest rivers: the Sacramento flowing south from its headwaters near Mt. Shasta and the San Joaquin flowing north from its origins high in the southern Sierra Nevada. Joining the Sacramento and the San Joaquin are the Mokelumne and the Cosumnes rivers that comprise the Delta’s watershed, draining nearly 50 percent of the California’s runoff. These waters of the Delta flow westward, through 57 man-made levied islands and tracks. Pumping stations move a portion of this water throughout the state: the State Water Project, the federal Central Valley Project, Contra Costa Canal, North Bay Aqueduct, City of Vallejo diversion and the Western Delta Industry diversion. The remainder of Delta water flows to farms and communities within the Delta, and then out to sea through a series of bays.
 

Demand management measures

A local resource, such as water conservation, that can be utilized to supplement water demand by reducing demands on the water supply.
 

Direct filtration

A method of treating water, which consists of mixing, coagulation, and filtration. Similar to conventional treatment with the exception of omitting flocculation and sedimentation.
 

Drought

A prolonged period of below-average precipitation.
 

Dry year

A year in which rainfall is less than the long-term average.
 

Emergency storage

Additional water that is stored during a water year, for emergency use, should an emergency occur.
 

Emergency Storage Project (ESP)

A set of Authority Capital Improvement Program projects, the ESP (link to 4.1.1.2.1 Emergency Storage Project) is a system of reservoirs, interconnected pipelines and pumping stations designed to make water available to all communities in the San Diego region in the event of a disaster that interrupts imported water deliveries. ESP projects include the completed Olivenhain Dam (link to 4.1.1.2.5 Olivenhain Dam Project), as well as facilities currently in construction: Lake Hodges Projects (link to 4.1.1.2.2 Lake Hodges Projects), San Vicente Pipeline (link to 4.1.1.2.8 San V Pipeline), and San Vicente Dam Raise (link to 4.1.1.2.7 San V Dam Raise).
 

Evaporation

Water changing into vapor and rising into the air.
 

Environmental impact

The direct and indirect physical changes that are caused by the project. Impacts can be classified in four general categories: 1) beneficial impact; 2) less than significant impact; 3) less than significant impact with incorporation of mitigation measures; or 4) significant and unavoidable impact.
 

Environmental impact report

A document required by the California Environmental Quality Act that evaluates a project, along with project alternatives, for its impact to the environment and social ecosystem.
 

Environmental impact statement

A document required by the National Environmental Policy Act that evaluates a project, along with project alternatives, for its impact to the environment and social ecosystem.
 

Environmental setting

The existing physical conditions that may be affected by a proposed project, including both natural and man-made conditions.
 

Environmental Water Account

A CALFED program with an objective to acquire water for endangered species protection and recovery and to hold this water in reserve to use when endangered species need it most.
 

Facilities

As it pertains to the Water Authority, any pipelines, pump stations, flow control facilities, reservoirs, or dams that enable the transport of water throughout San Diego County. See the facilities page here.
 

Fallowing


A program to generate water by paying farmers to fallow land, i.e., not grow crops. The water not used for irrigation is then transferred to urban areas or stored for future use.
 

Findings

Written determinations made by a public agency for each significant impact identified in the certified final environmental impact report, accompanied by a brief explanation of the rational for each determination. The lead agency must make findings prior to approving the project.
 

First Aqueduct

The eastern of two pipeline aqueducts of the San Diego County Water Authority which conveys water from Metropolitan Water District’s system throughout San Diego County. Also referred to as Pipelines 1 and 2.
 

Fiscal year

For the Authority, a period of time for which budgets and schedule milestones are set. The Authority’s fiscal year runs from July through June, spanning two calendar years.
 

Graywater

Typically, household wastewater not subject to human waste (such as showers and clothes wash water) that can be reused for landscape irrigation without further treatment.
 

Groundwater

Water that is found below the Earth’s surface within aquifers and extracted for potable use either for demineralization treatment or directly through residential wells.
 

Historic water demand

The amount of water demand that has historically been purchased, by member agency, as logged in the Authority’s Prima database.
 

Hydroelectric Plant

A power plant that produces electricity from the power of rushing water turning turbine-generators.

Hydrology
The scientific study of the behavior of water in the atmosphere, on the Earth's surface and underground.
 

Irrigation

Supplying water to agriculture by artificial means, such as pumping water onto crops in an area where rainfall is insufficient.
 

Imported water supplies

A water supply which lies outside the region of San Diego County and requires transport into San Diego County.
 

Law of the River

A complex body of laws, court decrees, contracts, agreements, regulations and an international treaty used to govern allocation and management of Colorado River water.
 

Lead agency

The public agency responsible for preparing an environmental impact report that complies with the provisions of the California Environmental Quality Act.
 

Limited imported supply

A scenario within the Authority’s Imported Supply Model, having supply from Metropolitan Water District constrained to the Authority’s preferential right.
 

Local resource

Water that we do not have to import from outside of San Diego County. Local resources for the San Diego region are recycled water, groundwater, local surface water and conservation.
 

Member agency

An agency that is a direct purchaser of water from the Authority. The Authority has 24 member agencies.

MAF

Million acre-feet
 

MGD

Millions of gallons per day
 

Microfiltration

A method of water filtration, using a pressure-driven membrane process, which includes particle filters that reject particles larger than 1.0 micron in size. Provides a less refined effluent than ultrafiltration.
 

Mitigation

A way in which an agency may offset negative environmental impacts of a project or make the impacts less serious.

Mitigation Monitoring or Mitigation Reporting Plan

A written document, adopted when the lead agency approves a project, to ensure that mitigation measures or other project revisions identified in the certified final environmental impact report to reduce or avoid impacts are implemented. Inspectors/monitors may be placed on-site during construction to record proper implementation of mitigation measures. The Plan remains active until all mitigation measures have been satisfactorily completed.
 

Mulch

Material spread on the ground to reduce soil erosion and evaporation of water; include hay, plastic sheeting and wood chips.


 

Municipal and Industrial (M&I) Water

Water for residential and commercial uses, accounting for approximately 80 to 85 percent of Water Authority demand. Does not include agricultural water, which makes up the remaining 15 to 20 percent.
 

Municipal Water District

A public water provider governed by a locally elected board of directors, which supplies water to the public directly or through subagencies.
 

Non-Peak delivery

The delivery of water during any event that is not a peak event (see “peak season”).
 

Non-Potable water

Water not treated to a level for drinking water purposes.
 

Peak Delivery

The delivery of water during a peak demand event such as a peak day (see “peak season”).
 

Peak or Maximum flow rate

The flow rate through a pipeline when a peak delivery is made. Also known as a maximum flow rate.
 

Peak Season

The months of the year that water demand is typically the highest, from June to October, inclusive. The remaining months comprise the off-peak season.
 

Point Forecast

An estimate of the most probable demand forecast for each year.
 

Potable Water

Water suitable for drinking water purposes.
 

Preferential Rights

An antiquated formula used by Metropolitan Water District of Southern California to calculate the amount of water to which each member agency is legally entitled. Under Section 135, each MWD member agency has a preferential right to a percentage of MWD’s available water supplies based on a formula established in the MWD Act
 

Project alternatives

A reasonable range of options to the proposed project whereby most of the basic project objectives can be feasibly attained and significant environmental impacts can be avoided or substantially lessened. At least two are required in every environmental impact report: 1) no project alternative; and 2) environmentally superior alternative. The range of alternatives is developed by considering the economic, social, environmental, legal and technical merits of various project options.
 

Project description

A project description is an essential element of an environmental impact report (EIR). It should minimally include the location of a project (with maps), a description of the facility to be built, construction techniques, the location of any additional work and staging areas, as well as any access roads. It should also include a description of the long-term operation and maintenance of the facility.
 

Pumping Plant

Facility that lifts water up and over the hills
 

Quantification Settlement Agreement (QSA)

An agreement between the San Diego County Water Authority, Coachella Valley Water District, Imperial Irrigation District, and the Metropolitan Water District of Southern California signed in 2003. The QSA provides California a transition period to implement water transfers and supply programs that will reduce California's over-dependence upon the Colorado River and reduce the state's draw to its 4.4 million acre-foot annual apportionment, and clears the way for the annual transfer of up to 200,000 acre-feet of water from the Imperial Irrigation District to the Water Authority. An additional 77,700 acre-feet of water will flow annually to the Water Authority for 110 years through the lining of the All-American and Coachella canals. When the deliveries of the water are fully ramped up, San Diego County will receive nearly 280,000 acre-feet of new, highly reliable water supplies. The QSA also commits the state to a restoration path for the environmentally sensitive Salton Sea as well as full mitigation for these water supply programs.
 

Reclaimed water

Municipal wastewater that has been treated and disinfected for non-potable reuse. Also known as recycled water.
 

Recycled water

Municipal wastewater that has been treated and disinfected for non-potable reuse. Also known as reclaimed water.
 

Relining Program

A San Diego County Water Authority program, which designates the pipeline projects for rehabilitation and relining, defined from the Authority’s Aqueduct Protection Program.
 

Regional Water Facilities Master Plan

A long-term plan that serves as a roadmap for implementing the major capital improvements needed to ensure a safe and reliable water supply for San Diego County through 2030. The Regional Water Facilities Master Plan focuses on diversifying San Diego County's water supply to reduce the region's over-reliance on a single source of imported water. The master plan examines several alternative new water supplies and identifies seawater desalination as the most reliable and preferred of the alternatives. The master plan also identifies individual projects needed to expand the capacity of the Water Authority's existing aqueduct system and to increase water treatment and storage. Increased water conservation and increased use of groundwater and recycled water will also play important roles in meeting future water demands.
 

Reservoir

A pond or lake where water is collected and stored until it is needed.
 

Reverse osmosis

The mechanical treatment process by which seawater desalination is accomplished. Seawater desalination is the overall treatment process by which a highly pressurized membrane system removes metal and salt ions to produce a potable water supply.
 

Runoff

Liquid water that travels over the surface of the Earth, moving downward due to the law of gravity; runoff is one way in which water that falls as precipitation returns to the ocean
 

Salinity

The scaling or white deposits that accumulate on coffee pots, water heaters and plumbing fixtures resulting from dissolved mineral salts in the water. Also known as total dissolved solids or TDS.
 

Seasonal storage

Additional water that is stored during a wet season, to be utilized in the following dry season.
 

Seawater desalination

The overall treatment process by which highly pressurized seawater is taken through a series of membrane filters to remove salts and produce a potable water supply. Reverse osmosis is the mechanical treatment process by which seawater desalination is accomplished. The Water Authority is planning for seawater desalination to provide 10% of the region’s water in 2020.
 

Second Aqueduct

The western of two pipeline aqueducts of the San Diego County Water Authority which conveys water from Metropolitan Water District’s system throughout San Diego County. The Second Aqueduct contains Pipelines 3, 4, and 5.
 

State Water Project (SWP)

A water storage and delivery system of reservoirs, aqueducts, power plants, and pumping plants which extends over two-thirds of California.
 

Statement of overriding considerations

A written statement by the lead agency to support a decision to take an action even though it results in significant and unavoidable impacts to the environment. The statement contains the specific reasons why the benefits of the action outweigh the environmental detriments.
 

Surface runoff

The amount of rainfall water that does not percolate into the ground prior to flowing by gravity to surface storage.
 

Surface Water

All water, fresh and salty, on the Earth's surface.
 

Treated/filtered water

Water that meets the Department of Health Services standards for potable drinking water use.
 

Ultrafiltration

A method of membrane water filtration which includes particle filters that reject particles larger than 0.1 microns in size; provides a more refined effluent than microfiltration.
 

Untreated/raw water

Water that has not yet been treated to meet the Department of Health Services standards for potable drinking water use.
 

Urban Water Use

Same as Municipal and Industrial Water - Water for residential and commercial uses, accounting for approximately 80 to 85 percent of Water Authority demand. Does not include agricultural water, which makes up the remaining 15 to 20 percent.
 

Useful Life

The period of time in which a facility operates without need for replacement.
 

Wastewater

Water that has waste material in it.
 

Water Demands

The amount of water, at present, that is required to meet the needs of a specified group.
 

Water Facilities

As it pertains to the Water Authority, any pipelines, pump stations, flow control facilities, reservoirs, or dams that enable the transport of water throughout San Diego County. See the facilities page here.
 

Water Reclamation

The treatment and disinfection of municipal wastewater to provide a water supply suitable for non-potable reuse.
 

Water Recycling

The treatment and disinfection of municipal wastewater to provide a water supply suitable for non-potable reuse.
 

Watershed

A region or area of land bounded peripherally by a water parting and draining ultimately to a specific watercourse or body of water.
 

Water Supplies

The amount of water, at present, that is available to meet the needs of a specified group.
 

Water Use

The amount of water that is used.
 

Water Year

The months from October to September, spanning two calendar years, beginning with first month of the wet season.
 

Wet season

A period of eight months, spanning two calendar years from October to May, in which rainfall is typically prevalent in the Southern California. The remaining months comprise the dry season.
 

Wet Year

A year in which rainfall is significantly greater than the long-term average.