Gate, slide gate Device used to control the flow of water to, from, or in a pipeline or open channel.

Gated pipe Portable pipe with small gates installed along one side for distributing irrigation water to corrugations or furrows.

Gear drive sprinkler Sprinkler containing gears as part of its rotational drive mechanism.

GPM Acronym for gallons per minute..

Gravitational water Soil water that moves into, through, or out of the soil under the influence of gravity.

Gravity (acceleration due to) Acceleration caused by the attraction of the mass of earth to bodies at or near its surface.

Gray water Domestic wastewater other than that containing human excreta such as sink drainage, washing machine discharge, or bath water.

Gross irrigation Total irrigation requirement including net crop requirement plus any losses  incurred in distributing and applying and in operating the system.

Ground water   Water occurring in the zone of saturation in an aquifer or soil.

Growing season {days} Period, often the frost-free period, during which the climate is such that crops can be produced.

Gypsum block   Electrical resistance block in which the material used to absorb water is gypsum.  It is used to measure soil water content in non-saline soils.