Gage pressure is the usual term that refers to the pressure measured relative to the atmospheric pressure.
Gallons per Minute (GPM)
GPM is a unit of measure used to indicate the rate of water flow. It signifies how many gallons are pumped out by equipment, an outlet or a drain from a water source every minute.
The gaseous state is a state of matter wherein the material has very low density and viscosity. A gas can expand and contract in large proportions as a response to temperature and pressure changes. A gas can easily diffuse with other gases and can uniformly distribute itself throughout any vessel or container. A gas can be changed to another state of matter through the combined effect of increased pressure and lowered temperatures.
Geographic Information System (GIS)
The GIS is a system that retrieves electronic files and databases of environmental measurements taken from a specific location and merges them with electronic maps showing geographic features. This system allows scientist to show large amounts of data on a particular location on a map. Information includes lanscape features as well as wetlands and land use.
The energy that is generated by the natural heat and water resources under the surface of the Earth is called geothermal energy. This includes the energy derived from volcanoes and hot springs.
Gleying is a term used to describe the formation of black, gray, greenish or blue-gray color in soils after a flood.
Global warming refers to the gradual rise of the Earth’s average global temperature resulting in gradual changes in global weather patterns. Global warming is often used interchangeably with climate change, and researchers and scientists have attributed this to the accumulation of greenhouse gases in the atmosphere. The scientific community have focused emphasis from proving global warming exists to finding ways to minimize the potential damage it can cause the environment and the entire planet. Examples of damages are the melting of glaciers, which the US Geological Survey says to be as high as 87 percent from the 244 glaciers studied. When glaciers melt, sea levels will rise resulting in a rash of floods and storms affecting several locations worldwide.
Granite is a medium to coarse and widely occurring type of intrusive, felsic, igneous rock. Rich in quartz and potassium feldspar, granite occasionally contains individual crystals larger than the groundmass. Granites can be pink, dark gray or black and depends on the chemistry and mineralogy. This type of rock is common throughout the world, but certain areas are well known for producing commercial granite. Due to its relatively impervious and inflexible qualities, granite is widely used as a dimension stone and is used by engineers to establish a plane of reference for measurements. Granite is also commercially used as flooring tiles in homes, buildings and monuments.
Gravel is basically a natural accumulation of rounded rock fragments that are larger than two millimeters and less than 63 millimeters. These include fragments from boulders, cobbles, pebbles, granules or any combination of these rock particles. Gravel is used in many commercial and industrial applications as a mixture for concrete. Gravel is also used in rural areas as a surface for roadways where there is minimal traffic.
Gray Water / Greywater
Gray water is also known as sullage and refers to the non-industrial wastewater from households and small commercial establishments generated from domestic activities like dish washing, laundry and bathing. This is basically 50 to 80 percent of residential wastewater, but excludes water from toilets which is classified differently as blackwater. Gray water derives its name from its cloudy appearance and is neither fresh nor heavily polluted. Gray water is classified differently from blackwater, which contains fecal matter and toxic chemicals.
A grease fire refers to the type of fire resulting from cooking oil or any other flammable cooking or lubricating materials. These types of fires are classified as Class B, F or K fires.
Green algae are the most common and largest group of algae with more than 7,000 known species. Green algae have nucleated cells and chloroplasts, which give it the ability to produce food from sunlight. Algae can be found mostly in estuaries and are an intrinsic part in several ecosystems.
The greenhouse effect refers to the accumulation of greenhouse gases in the Earth’s atmosphere resulting in a rise in global temperatures. These greenhouse gases include carbon dioxide, nitrous oxide, chlorofluorocarbons (CFCs), ozone and methane. These gases trap reflected radiant energy that tries to leave the planet.
Greenhouse gases are released in large quantities into the environment as a result of human activities. This includes water vapor, carbon dioxide, nitrous oxide, ozone and methane. Greenhouse gases are believed to contribute to global warming.
Ground Fault Interrupter (GFI)
A GFI is a safety device installed in a home or a structure that aims to interrupt surges in electricity from the electrical power lines, appliances and other electrical devices and components.
Groundwater is subsurface water coming from undergound streams that can be collected through wells. Groundwater can also flow naturally towards the surface of the earth in the form of springs. Groundwater is also a potential source of drinking water. Environmental restoration and management is performed to prevent groundwater contamination from pesticides, sewage, industrial wastes and runoffs from agricultural lands.
A reservoir for groundwater is called a groundwater basin. It is defined and bounded by an overlying land surface and underlying aquifers from water is stored in the reservoir. An aquifer is a layer of water-bearing permeable rocks containing gravel, sand, silt or clay. An aquifer is where a groundwater is extracted.
A groundwater overdraft is a condition where the amount of water drawn by pumping from a groundwater basin is more than what the basin can recharge over a period of years.
Also called a downspout or eavetrough, a gutter is a channel attached to the eaves of the roof for the purpose of diverting water away from the foundation of a home. Gutters are made of various materials, but are usually made of vinyl, plastic, copper or galvanized iron sheets.
Gypsum is hydrated calcium sulphate, a pale sedimentary rock that is usually ground and mixed with plasters, cement and fertilizers. Gypsum is used to make plasterboard or drywall.