- Gateways. An Urban space or architectural element that announces the arrival to, or departure from a place. A point of arrival.
- Greenhouse gas (GHG). Any gas that absorbs infrared radiation in the atmosphere. State law identifies seven greenhouse gases for which the California Air Resources Board is responsible to monitor and regulate in order to reduce GHG emissions: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and nitrogen trifluoride (NF3).
- Goal. A statement of desired future conditions regarding a particular topic; a goal paints a picture of how something will be in the future. A goal in and of itself is not sufficient to understand its intent, extent, or context. A goal itself is kept simple, with policies, objectives, and implementation actions providing further definition.
- Goods movement. The transport of products from their manufacturing origin to their final destination where they will be sold, stored, or used. Moving goods involves airplanes, ships, trains, and trucks.
- Grade separation. A bridge or tunnel for a highway, road, or railroad that allows pedestrians, bicyclists, or even cars to cross a major roadway without conflict or delay for a signal light. Without grade separations, vehicles, and bicycles, and pedestrians must physically cross tracks.
- Greywater/graywater. Wastewater that is generated in residential buildings, excluding sewage, such as gently used water from bathroom sinks, showers, tubs, and washing machines. The wastewater generated by toilets, kitchen sinks, and dishwashers is called blackwater due to its larger organic load (fecal or organic matter).
- Groundwater. Water under the earth’s surface, often mapped as basins and confined to aquifers capable of supplying wells and springs.
- Groundwater recharge. The natural process of infiltration and percolation of rainwater from land areas or streams through permeable soils into water-holding rocks that provide underground storage in aquifers. This process can also be conducted artificially by capturing and injecting surface water or recycled water into aquifers.
- Ground Failure. Mudslide, landslide, liquefaction, or the seismic compaction of soils.