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Gaging station: The site on a
stream, lake or canal where hydrologic data is collected.
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Gallon: A unit that is
now almost entirely out of date. It is equivalent to 3.785 liters.
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Gallon: A unit of volume.
A U.S. gallon contains 231 cubic inches, 0.133 cubic feet, or 3.785 liters.
One U.S. gallon of water weighs 8.3 lbs.
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Geohydrology: A term which
denotes the branch of hydrology relating to subsurface or subterranean waters;
that is, to all waters below the surface.
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Geologic
erosion: Normal
or natural erosion caused by geological processes acting over long geologic
periods and resulting in the wearing away of mountains, the building up of floodplains,
coastal plains, etc.
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Geopressured
reservoir: A
geothermal reservoir consisting of porous sands containing water or brine at
high temperature or pressure.
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Geyser: A periodic thermal
spring that results from the expansive force of super heated steam.
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Giardia: A microorganism
that is commonly found in untreated surface water and can be removed by filtration.
It is resistant to disinfectants such as chlorine.
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Glacier: A huge mass of
ice, formed on land by the compaction and re-crystallization of snow, that moves
very slowly downslope or outward due to its own weight.
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Grab sample: A sample taken
at a given place and time. Compare composite sample.
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Granular
activated carbon:
Pure carbon heated to promote
"active" sites which can adsorb pollutants. Used in some home water treatment
systems to remove certain organic chemicals and radon.
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Gray water: Domestic wastewater
composed of washwater from kitchen sinks, bathroom sinks and tubs, clothes washers,
and laundry tubs.
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Greenhouse
effect: The warming
of the earth's atmosphere caused by a build-up of carbon dioxide or other trace
gases; it is believed by many scientists that this build-up allows light from
the sun's rays to heat the earth but prevents a counterbalancing loss of heat.
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Greywater: Wastewater from
clothes washing machines, showers, bathtubs, hand-washing, lavatories and sinks
that are not used for disposal of chemical or chemical-biological ingredients.
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Groundwater: Generally all
subsurface water as distinct from surface water; specifically, that part of
the subsurface water in the saturated zone (a zone in which all voids are filled
with water) where the water is under pressure greater than atmospheric.
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Groundwater
discharge: Ground
water entering coastal waters, which has been contaminated by land-fill leachates,
deep well injection of hazardous wastes and septic tanks.
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Groundwater
disposal: Wastewater
that is disposed of through the ground either by injection or seepage. This
includes the following discharge methods; absorption beds, injection wells,
drainfields, percolation ponds, rapid infiltration basins, spray fields, and
land application systems. Land application systems or reuse systems are considered
a ground-water disposal as treated wastewater used to irrigate is generally
intended to filter down through the soil.
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Groundwater
hydrology: The
branch of hydrology that deals with groundwater; its occurrence and movements,
its replenishment and depletion, the properties of rocks that control groundwater
movement and storage, and the methods of investigation and utilization of ground
water.
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Groundwater
law: The common
law doctrine of riparian rights and the doctrine of prior appropriation as applied
to ground water.
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Groundwater
recharge: The
use of reclaimed wastewater, by surface spreading or direct injection, to prevent
saltwater intrusion into freshwater aquifers, to store the reclaimed water for
future use, to control or prevent ground subsidence, and to augment non-potable
or potable ground water aquifers.
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Groundwater
reservoir: An
aquifer or aquifer system in which ground water is stored. The water may be
placed in the aquifer by artificial or natural means.
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Groundwater
runoff: The portion
of runoff which has passed into the ground, has become ground water, and has
been discharged into a stream channel as spring or seepage water.
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Groundwater
storage: The
storage of water in groundwater reservoirs.
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Gully: A deeply eroded
channel caused by the concentrated flow of water.
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Gully reclamation: Use of small
dams of manure and straw; earth, stone, or concrete to collect silt and gradually
fill in channels of eroded soil.
