Glossary G-L

G H I J K L

Geographic Information System (GIS)—a geographically referenced database that connects information about things to locations, which can be referenced by any convenient system such as latitude and longitude or three-dimensional coordinates.

Global Positioning System (GPS)—a system that establishes the precise location of a radio-based computer receiving signals from orbiting space satellites, possibly in combination with the use of a transmitter and a local base station.

Gravity—the gravitational attraction of the earth's mass for bodies at or near its surface.

greywater—untreated water after it has been used for showering, bathing, clothes washing, hand washing and faucet uses. Water contaminated by human or animal wastes or by chemicals is not considered greywater.

groundwater—the supply of fresh water found beneath the Earth's surface (usually in aquifers), often used for supplying wells and springs.

groundwater recharge recovery—the withdrawal of banked groundwater recharge for use as a part of the water supply.

G H I J K L

Hardness—that characteristic of water caused by calcium and magnesium that causes scaling, spots on glassware and other aesthetic concerns. Colorado River water in Lake Mead is considered to be very hard, having a calcium carbonate value of about 300 milligrams per liter.

hardwater—water that contains minerals, especially calcium and magnesium ions, that cause soap to precipitate producing a scum or scale in boilers.

Hydroelectric—having to do with the production of electricity by waterpower.

Hydrogeology —the science dealing with the occurrence, distribution and movement of water below the surface of the Earth with a greater emphasis on geology.

hydrologic cycle—the process of water's movement form the atmosphere to the land or ocean and back into the atmosphere using the processes of precipitation, condensation, evaporation and transpiration.

Hydrologist—a person who applies scientific knowledge and mathematical principles to solve water-related problems in society, such as problems of quantity, quality and availability.

Hydrology—the study of water, its properties, its distribution on Earth and its effects on the Earth's environment.

Infiltration—the gradual downward flow of water from the surface into soil material.

Impermeable Layer —a layer of solid material, such as rock or clay, which does not allow water to pass through.

influent—wastewater flowing into a wastewater treatment facility.

Intake—the first point of entry for water flowing into a process or system. The Southern Nevada Water System's two primary water intakes are located at Saddle Island, more than 100 feet beneath the surface of Lake Mead.

intake system—the collection of integrated components that transmit water to the Southern Nevada Water System. The intake system may consist of an intake structure, tunnel, pumping equipment, metering equipment and piping.

ion—an atom or molecule that has lost or gained one or more electrons.

irrigation—a system of pipes or canals used to bring water to places where it is needed.

G H I J K L

lake—a large standing body of water surrounded by land.

Lake Mead—one of the largest artificial lakes in the world (115 miles long), created when Hoover Dam was built on the Colorado River.

lateral—a distinct branch of the transmission facility serving a particular turnout or small group of turnouts.

Las Vegas Valley—the topographic basin containing the City of Las Vegas, the City of North Las Vegas, the City of Henderson and certain unincorporated townships of Clark County.

Las Vegas Valley Water District (LVVWD)—a water purveyor that serves approximately 800,000 people in Southern Nevada, including the City of Las Vegas and other unincorporated areas within Clark County. LVVWD is a member of the Southern Nevada Water Authority and the authorized operating agency for SNWA affairs and the Southern Nevada Water System.

Las Vegas Wash—the primary drainage channel for the Las Vegas Valley Hydrographic Basin. Originating from a series of ephemeral creeks, desert washes and runoff channels in the far northern and western parts of the hydrographic basin, the wash takes shape in the eastern and southeastern metropolitan Las Vegas Valley, tracing a 12-mile-long curve that ends at Las Vegas Bay in Lake Mead.

leaching—the removal of water action of chemical elements and compounds from rocks and soil.

leak—to pass through a small hole or crack.

liquid—fluid matter that takes the shape of its container.

liter—1,000 milliliters.

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