Water terms starting with G

103 terms

Gabion Wire basket, filled with stones, used to stabilize banks of a water course and to enhance habitat.
Gabion dam Special name given to a crib dam when built with gabions. See dam.
Gage (1) A device for indicating the magnitude or position of a thing in specific units, when such magnitude or position undergoes change, for example: The…
Gage Datum The arbitrary zero datum elevation which all stage measurements are made from.
Gage Height The water-surface elevation referred to some arbitrary gage datum. Gage height is often used interchangeably with the more general term stage, although…
Gage height (G.H.) The water surface elevation referred to some arbitrary gage datum. Gage height is often used interchangeably with the more general term "stage," although…
Gage Zero The elevation of zero stage. (Same as gage datum.)
Gaging Station A particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are obtained.
Gaining stream Stream or reach that receives water from the zone of saturation.
Gallery A passageway within the body of a dam, its foundation, or abutments used for inspection, foundation grouting, and/or drainage.
Gallon A unit of measure equal to four quarts or 128 fluid ounces.
Galvanize To coat a metal (especially iron or steel) with zinc. Galvanization is the process of coating a metal with zinc.
Gametes Eggs or sperm.
Gantry An overhead structure that supports machines or operating parts, such as a gantry crane.
Gantry crane A fixed or traveling, bent-supported crane for handling heavy equipment.
Gaseous supersaturation Condition of higher levels of dissolved gases in water due to entrainment, pressure increases, or heating.
Gate A device that controls the flow in a conduit, pipe, or tunnel without obstructing any portion of the waterway when in the fully open position.
Gate chamber (valve chamber) A chamber in which a guard gate in a pressurized outlet works or both the guard and regulating gates in a free-flow outlet works are located.
Gate hanger A device used to maintain a set gate opening.
Gate structure Portion of spillway between inlet channel and chute, tunnel or conduit, which contains gates, such as radial gates.
Gate valve A valve with a circular-shaped closing element that fits securely over an opening through which water flows.
Gated pipe Portable pipe with small gates installed along one side for distributing irrigation water to corrugations or furrows.
Gated spillway Overflow section of dam restricted by use of gates that can be operated to control releases from the reservoir to ensure the safety of the dam.
Gauge (gage) Device for registering water level, discharge, velocity, pressure, etc. Thickness of wire or sheet metal.
Gauge height Elevation of water surface measured by a gauge. See gage height.
Gauge pressure Absolute pressure minus atmospheric pressure. The pressure within a closed container as measured with a gauge. Sometimes referred to as relative pressure.
Gauging station Specific location on a stream where systematic observations of hydrologic data are obtained through mechanical or electrical means. See gauge.
Generation The electricity generated by a system as recorded by a KWH meter, recorded in KWH or MWH.
Generation dispatch and control Aggregating and dispatching (sending off to some location) generation from various generating facilities, providing backup and reliability services.
Generator A device for converting mechanical energy to electrical energy.
Generator nameplate capacity The full-load continuous rating of a generator, prime mover, or other electric power production equipment under specific conditions as designated by the…
Geographic Information System (GIS) A set of computer tools and procedures used to collect, manage, analyze and display information associated with a specific location; a computerized…
Geohydrology Geological study of the character, source, and mode of ground water.
Geology The science that deals with the study of the materials, processes, environments, and history of the Earth, including the rocks and their formation and…
Geomorphic Pertaining to those processes that affect the form or shape of the surface of the earth.
Geomorphology Geological study of the configuration, characteristics, origin, and evolution of land forms and earth features.
Geophysics Refers to the physics of the earth, e.g., seismology, oceanography, volcanology, geomagnetism, etc.
Geostationary Orbiting Environmental Satellite (GOES) Satellite orbiting at 22,000 miles above the earth's surface that remains above the same location on the earth.
Geotextiles Any fabric or textile (natural or synthetic) used as an engineering material in conjunction with soil, foundations, or rock.
Giant salvinia (Salvinia molesta) An aquatic fern prohibited in the United States by Federal law. An invasive, rapidly growing plant that covers the surfaces of lakes and streams forming…
Gigawatt (GW) A unit of power equal to 1 billion Watts; 1 million kilowatts, or 1,000 megawatts.
Gigawatt-hour (GWh) One billion watthours of electrical energy.
Glacial moraine A mass of loose rock, soil, and earth deposited by the edge of a glacier.
Glacial striations Lines carved into rock by overriding ice, showing the direction of glacial movement.
Glacial till An unsorted, unstratified mixture of fine and coarse rock debris deposited by a glacier.
Glacier Bodies of land ice that consist of recrystallized snow accumulated on the surface of the ground, and that move slowly downslope.
Glacier (ice sheet) A large thick mass of ice formed on land by the compacting and recrystallization of old snow and move under the influence of gravity.
Glacier Dammed Lake The lake formed when a glacier flows across the mouth of an adjoining valley and forms an ice dam.
Global positioning systems (GPS) Space-based radio positioning systems that provide 24-hour, three-dimensional position, velocity, and time information to suitably equipped users anywhere…
Gneiss Metamorphic rock that displays distinct banding of light and dark mineral layers.
GOES Data Collection System (DCS) A data collection system under NESDIS which is comprised of the DCPs, and the NESDIS Command and Data Acquisition (CDA) System components.
Goggle valve. See ring follower gate.
Graben Down-dropped block of rock bounded on both sides by faults. See fault-block.
Gradation Proportion of material of each grain-size present in a given soil. The proportions by mass of a soil or fragmented rock distributed in specified…
Grade (pitch) The elevation of a surface or a surface slope. The elevation of the invert of the bottom of a pipeline, canal, culvert, or conduit.
Grade stake A stake indicating the amount of cut or fill required to bring the ground to a specified level.
Graded stream Streams that receive and carry away equal amounts of sediment.
Grader A machine with a centrally located blade that can be angled to cast to either side, with independent hoist control on each side.
Gradient General slope or rate of change in vertical elevation per unit of horizontal distance of water surface of a flowing stream.
Granite A coarse-grained felsic intrusive (or plutonic) igneous rock with at least 65% silica.
Granitic General term for all light-colored, granite-like igneous rocks.
Granodiorite Coarse-grained intrusive igneous rock with less quartz and more feldspar than true granite and typically darker.
Grapple A clamshell-type bucket having three or more jaws.
Gravel Loose rounded fragments of rock that will pass a 3-inch sieve and be retained on a No. 4 U.S. Standard sieve (3/16 inch).
Gravel blanket Thin layer of gravel spread over an area either of natural ground, excavated surface, or embankment.
Gravel surfacing Layer of gravel spread over an area intended for vehicular or personnel traffic, such as roads, parking lots and sidewalks.
Gravelfill Gravel used to fill holes or spaces.
Gravity arch dam A dam designed to combine load resisting features of both a gravity and arch type dam.
Gravity Dam A dam constructed of concrete and/or masonry which relies on its weight and internal strength for stability.
Gravity irrigation Irrigation method that applies irrigation water to fields by letting it flow from a higher level supply canal through ditches or furrows to fields at a…
Gray water Wastewater other than sewage, such as sink and bath drainage or washing machine discharge.
Grid A common term referring to an electricity transmission and distribution system.
Grid operator An entity that oversees the delivery of electricity over the grid to the customer, ensuring reliability and safety.
Grizzly (grizzlie) A coarse screen used to remove oversize pieces from earth or blasted rock. A gate or closure on a chute.
Groin The area where the thigh meets the abdomen.
Gross crop value This value is the sum of annual receipts from sale of crops produced. Production of crops, such as pasture and hay which normally are consumed on the farm…
Gross Generation The total amount of electricity produced by a power plant.
Ground motion A general term including all aspects of ground motion, namely particle acceleration, velocity, or displacement, from an earthquake or other energy source.
Ground motion parameters Numerical values representing vibratory ground motion, such as particle acceleration, velocity, and displacement, frequency content, predominant period…
Ground receive sites A satellite dish and associated computer which receives signals from the GOES satellite, decodes the information, and transmits it to a another site for…
Ground Water Water that flows or seeps downward and saturates soil or rock, supplying springs and wells.
Ground Water Divide A line on a water table where on either side of which the water table slopes downward.
Ground Water Flow Streamflow which results from precipitation that infiltrates into the soil and eventually moves through the soil to the stream channel.
Ground Water Hydrology The branch of hydrology that specializes in ground water; its occurrence and movements; its replenishment and depletion; the properties of rocks that…
Ground Water Mining Pumping ground water from a basin where the safe yield is very small, thereby extracting ground water which had accumulated over a long period of time.
Ground water mining (overdraft) Pumping of ground water for irrigation or other uses, at rates faster than the rate at which the ground water is being recharged.
Ground Water Outflow That part of the discharge from a drainage basin that occurs through the ground water.
Ground Water Overdraft Pumpage of ground water in excess of safe yield.
Ground water recharge The flow to ground water storage from precipitation, inflitration from streams, and other sources of water.
Ground Water Runoff That part of the runoff which has passed into the ground, has become ground water, and has been discharged into a stream channel as spring, or seepage…
Ground water table The upper boundary of ground water where water pressure is equal to atmospheric pressure, i.e.
Ground-fault circuit interrupter (GFCI) An electrical device designed to protect people (not equipment) from electrical shock.
Grounded ice Ice that has run aground or is contact with the ground underneath it.
Grout A fluid mixture of cement and water or sand, cement, and water used to seal joints and cracks in a rock foundation.
Grout Blanket An area of the foundation systematically grouted to a uniform shallow depth.
Grout cap A concrete pad or wall constructed to facilitate subsequent pressure grouting of the grout curtain beneath the grout cap.
Grout Curtain A barrier produced by injecting grout into a vertical zone, usually narrow (horizontally), and in the foundation to reduce seepage under a dam.
Grout Curtain (Grout Cutoff) A vertical zone, usually thin, in the foundation into which grout is injected to reduce seepage beneath a dam.
Grouting Filling cracks and crevices with a cement mixture.
Growing Season The period, often the frost-free period, during which the climate is such that crops can be produced.